CN118934448A

CN118934448A - A method and device for controlling synchronous speed operation of a wind turbine generator set

Info

Publication number: CN118934448A
Application number: CN202411242087.3A
Authority: CN
Inventors: 张硕望; 胡书武; 袁黎龙; 童剑雄; 杨先有; 曹俊伟; 黄凌翔; 徐可; 周武喜; 高贤慧
Original assignee: Hunan Xinglan Wind Power Co ltd
Current assignee: Hunan Xinglan Wind Power Co ltd
Priority date: 2024-09-05
Filing date: 2024-09-05
Publication date: 2024-11-12

Abstract

A synchronous rotating speed section operation control method and device of a wind generating set relate to the field of wind power generation control, and the method comprises the following steps: determining a synchronous rotating speed interval according to the synchronous rotating speed of the asynchronous generator in the wind generating set and the corresponding rotating speed tolerance percentage; when the wind generating set generates wind energy, acquiring the real-time rotating speed of an asynchronous generator in the wind generating set; detecting the junction temperature of a power device of a converter in the wind generating set when the real-time rotating speed is in the synchronous rotating speed interval; when the junction temperature of the power device is higher than a first protection threshold value, storing the actual limiting power of the current wind generating set as the initial limiting power; the actual limiting power is regulated down to junction temperature protection power so as to reduce the junction temperature of the power device; and when the junction temperature of the power device is lower than a second protection threshold value, the actual limiting power of the wind generating set is returned to the initial limiting power. By implementing the method, the power generation loss of the unit can be reduced while the damage of the power device of the converter is avoided.

Description

Synchronous rotating speed section operation control method and device for wind generating set

Technical Field

The application relates to the field of wind power generation control, in particular to a method and a device for controlling synchronous rotation speed section operation of a wind generating set.

Background

The doubly fed wind generator set (DFIG) is one of the speed-increasing wind generator sets, and the proportion of the doubly fed wind generator set (DFIG) is higher in the in-service wind generator set. With market cost pressure, the problems related to the electric type of doubly fed wind power generator sets are also exposed in a large amount in recent years. Because of the cost control of the converter, when the wind generating set works in the synchronous rotating speed interval for a long time, the PWM switching frequency of the power device of the converter will become low, the junction temperature of the low-cost power device of the converter will obviously rise when the switching frequency becomes low, and the power device will be damaged due to the overhigh junction temperature for a long time, so that the normal operation of the wind generating set is affected.

In the related art, in order to prolong the service life of the power device of the converter, the wind generating set is prevented from working in a synchronous rotation speed interval as long as possible. The related technology can directly lead the rotating speed of the wind generating set to span the synchronous rotating speed interval by pressing the rotating speed of the wind generating set to enable the rotating speed to be lower than the synchronous rotating speed interval and then releasing the rotating speed to be higher than the high rotating speed of the synchronous rotating speed interval after accumulation for a period of time, so as to ensure that the wind generating set cannot work in the synchronous rotating speed interval.

However, the related art may have a part of wind energy wasted due to the process of suppressing the rotational speed, resulting in a decrease in the generation yield of the wind generating set.

Disclosure of Invention

The application provides a synchronous rotating speed section operation control method and device for a wind generating set, which are used for reducing the generating loss of the set while avoiding the damage of a power device of a converter.

In a first aspect, the present application provides a method for controlling synchronous speed segment operation of a wind generating set, applied to a generator control device, the method comprising: determining a synchronous rotating speed interval according to the synchronous rotating speed of the asynchronous generator in the wind generating set and the corresponding rotating speed tolerance percentage; when the wind generating set generates wind energy, acquiring the real-time rotating speed of an asynchronous generator in the wind generating set; detecting the junction temperature of a power device of a converter in the wind generating set when the real-time rotating speed is in the synchronous rotating speed interval; when the junction temperature of the power device is higher than a first protection threshold value, storing the actual limiting power of the current wind generating set as the initial limiting power; the actual limiting power is the maximum output power set in the current running process of the wind generating set, and the default value of the actual limiting power is the rated power of the set; the actual limiting power is regulated down to junction temperature protection power so as to reduce the junction temperature of the power device; and when the junction temperature of the power device is lower than a second protection threshold value, the actual limiting power of the wind generating set is returned to the initial limiting power.

In the above embodiment, the generator control device determines whether the wind turbine generator is in the synchronous rotation speed interval according to the real-time rotation speed, and monitors the junction temperature of the power device of the converter in real time when the wind turbine generator is in the synchronous rotation speed interval, and actively reduces the actual limited power to the junction temperature protection power when the junction temperature exceeds the first protection threshold value, so as to reduce the junction temperature of the power device. The mode avoids the damage caused by long-term high-temperature operation of the power device. Meanwhile, the actual limiting power of the current wind generating set is stored as the initial limiting power, and when the junction temperature is lower than the second protection threshold value, the actual limiting power is returned to the initial limiting power, so that the power generation loss of the wind generating set is reduced to the greatest extent.

In combination with some embodiments of the first aspect, in some embodiments, when the junction temperature of the power device is lower than the second protection threshold, the step of adjusting the actual limiting power of the wind generating set to the initial limiting power specifically includes: when the junction temperature of the power device is lower than a second protection threshold value, acquiring a power difference value between junction temperature protection power and initial limiting power; dividing the power difference value into a plurality of ordered power callback segments according to a preset power step length; adding a power callback segment for the actual limited power according to the arrangement sequence of the plurality of ordered power callback segments; if the junction temperature increment of the junction temperature of the power device is not higher than the preset abnormal threshold value in the preset test time, the next power callback section is added for the actual limiting power until the actual limiting power reaches the initial limiting power.

In the above embodiment, when the junction temperature of the power device is lower than the second protection threshold, the generator control device calculates a power difference between the junction temperature protection power and the initial limiting power, and then divides the difference into a plurality of ordered power callback segments according to a preset power step. And then, gradually increasing the actual limiting power according to the arrangement sequence of the power callback segments, monitoring whether the junction temperature increment exceeds an abnormal threshold value in the preset test time after each increase, and if not, continuing to increase the next segment until the initial limiting power is callback. The gradual power callback mode can avoid junction temperature sudden rise caused by sudden power increase, and more stably and safely callback the power to the initial level, so that the power device safety is ensured, and meanwhile, the power generation loss is reduced as much as possible.

With reference to some embodiments of the first aspect, in some embodiments, after the step of adding one power callback segment to the actual limited power in the order of the plurality of ordered power callback segments, the method further includes: if the junction temperature increment of the junction temperature of the power device is higher than a preset abnormal threshold value in the preset test time, the last power callback section is reduced for the actual limiting power until the actual limiting power reaches the junction temperature protection power.

In the above embodiment, in the process of gradually adjusting back the actual limiting power, if it is detected that the junction temperature increment exceeds the abnormal threshold, the generator control device actively reduces the last power adjustment segment until the junction temperature protection power is fallen back. The method is equivalent to setting a junction temperature abnormality detection mechanism in the callback process, and once junction temperature is found to rise too fast, power is timely reduced, and the situation that a power device enters a high-temperature dangerous zone again due to blind callback is avoided. Through the mechanism, the safety of the power device is further improved, and meanwhile, the power callback process is more stable and controllable.

With reference to some embodiments of the first aspect, in some embodiments, after the step of determining the synchronous speed interval from the synchronous speed of the asynchronous generator in the wind power generation set and the corresponding speed tolerance percentage, the method further comprises: determining a power scheduling dead zone corresponding to the wind generating set according to the synchronous rotating speed interval; acquiring scheduling limiting power issued by a power grid, and determining operation limiting power based on the scheduling limiting power and a power scheduling dead zone; and taking the operation limiting power as the actual limiting power, and controlling the wind generating set to generate wind energy.

In the above embodiment, after determining the synchronous rotation speed interval, the generator control device further determines the power scheduling dead zone corresponding to the wind generating set according to the interval. When the power network issues the scheduling limiting power, if the power is in the scheduling dead zone, the lower limit of the power dead zone is taken as the actual operation limiting power. The scheduling dead zone is utilized, so that the rotating speed can be controlled to be separated from the synchronous interval to a certain extent, the adjusting times are reduced, and the wind generating set can be operated as stably as possible, thereby being beneficial to the safety and the power generation efficiency of the set.

With reference to some embodiments of the first aspect, in some embodiments, determining a power scheduling dead zone corresponding to the wind generating set according to the synchronous rotation speed interval specifically includes: determining the output power of the wind generating set at the synchronous rotating speed, and taking the output power as a power dead zone center; determining a power dead zone upper bound and a power dead zone lower bound according to the power tolerance percentage and the power dead zone center to obtain a power scheduling dead zone; the power tolerance percentage is lower than the rotational speed tolerance percentage.

In the above embodiment, the generator control device directly uses the output power of the wind generating set at the synchronous rotation speed as the center of the power dead zone, and then determines the upper and lower bounds according to a given power tolerance percentage. The power tolerance percentage is set lower than the rotational speed tolerance percentage. The power is more sensitive to the change of the rotating speed, the dead zone of the power control is further compressed, the power limitation of the power grid is met for the purpose of energy management of the wind power plant, and the power grid friendliness is improved.

With reference to some embodiments of the first aspect, in some embodiments, obtaining a scheduling limit power issued by the power grid, determining an operation limit power based on the scheduling limit power and a power scheduling dead zone specifically includes: acquiring scheduling limiting power issued by a power grid, and determining whether the scheduling limiting power is within a power scheduling dead zone range; if the scheduling limit power is not in the power scheduling dead zone range, taking the scheduling limit power as the operation limit power; and if the scheduling limit power is within the power scheduling dead zone range, taking the lower limit of the power dead zone as the operation limit power.

In the above embodiment, when the scheduled power is within the power schedule dead zone, the generator control apparatus directly takes the power dead zone lower bound as the operation limiting power, without adopting the scheduled value. The method fully utilizes the margin of dead zone, and reduces the power adjustment times of the synchronous rotating speed section as much as possible. On the other hand, when the scheduling power is lower than the dead zone lower bound, the scheduling value is directly adopted as the running power. The synchronous rotating speed section keeps stable running as much as possible, and meanwhile, the requirement of power grid dispatching is also met.

With reference to some embodiments of the first aspect, in some embodiments, when the junction temperature of the power device is lower than the second protection threshold, after the step of turning back the actual limited power of the wind generating set to the initial limited power, the method further includes: recording the time when the actual limiting power is returned to the initial limiting power as the first time; obtaining the time when the junction temperature of the power device is higher than the first protection threshold again, wherein the time is the second time; and when the time difference between the second time and the first time is lower than the preset time difference, adjusting the junction temperature protection power based on the preset protection rule.

In the above embodiment, after the actual limiting power is successfully returned to the initial limiting power, the generator control device records the time of the return, and monitors the time when the subsequent junction temperature exceeds the first protection threshold again. If the time interval between the two times is lower than the preset time difference, the junction temperature rises too quickly, and the current junction temperature protection power needs to be adjusted, usually the protection power is further reduced to match the heat dissipation state of the current wind generating set.

In a second aspect, an embodiment of the present application provides a generator control apparatus including: one or more processors and memory; the memory is coupled to the one or more processors, the memory for storing computer program code comprising computer instructions that are invoked by the one or more processors to cause the generator control device to perform a method as described in the first aspect and any one of the possible implementations of the first aspect.

In a third aspect, embodiments of the present application provide a computer program product comprising instructions which, when run on a generator control apparatus, cause the generator control apparatus to perform a method as described in the first aspect and any possible implementation manner of the first aspect.

In a fourth aspect, embodiments of the present application provide a computer readable storage medium comprising instructions which, when run on a generator control apparatus, cause the generator control apparatus to perform a method as described in the first aspect and any possible implementation manner of the first aspect.

It will be appreciated that the generator control apparatus provided in the second aspect, the computer program product provided in the third aspect and the computer storage medium provided in the fourth aspect are each configured to perform the method provided by the embodiment of the present application. Therefore, the advantages achieved by the method can be referred to as the advantages of the corresponding method, and will not be described herein.

One or more technical solutions provided in the embodiments of the present application at least have the following technical effects or advantages:

1. The method for detecting the junction temperature and controlling the limiting power based on the converter power device is adopted when the real-time rotating speed of the asynchronous generator is located in the synchronous rotating speed interval, so that the limiting power can be timely reduced when the junction temperature exceeds the first protection threshold value to protect the converter, and the limiting power can be timely returned to avoid generating loss when the junction temperature is restored below the second protection threshold value, the problem that the converter junction temperature is damaged or the generating efficiency is reduced due to the fact that the junction temperature of the converter is ignored or the limiting rotating speed is limited in the prior art is effectively solved, and further the operation optimization control of the synchronous rotating speed section which takes the safety and the generating performance of the converter into consideration is realized.

2. The method for gradually adjusting the actual limiting power to the initial limiting power in a sectionalized manner, detecting junction temperature change in real time in the adjustment process, and continuously adjusting or reducing the adjustment power again according to whether the junction temperature is abnormal or not is adopted, so that the limiting power can be restored to the initial level required by the operation of the synchronous rotating speed interval in the most stable manner in the shortest time, the generation loss is reduced to the maximum extent, meanwhile, the junction temperature rebound is prevented, the problem that junction temperature fluctuation is easily caused by adopting single-step adjustment in the prior art, the generation loss time is easily prolonged by adopting slow linear adjustment is effectively solved, and the unified optimization of the efficiency and safety of the adjustment process is further realized.

3. The method for adaptively adjusting the junction temperature protection power of the converter according to the actual operation condition of the wind turbine generator, namely, the triggering time interval of junction temperature protection is recorded, so that the rationality of the current protection power can be objectively evaluated, the damage of the converter caused by insufficient protection is avoided, the reduction of the power generation efficiency caused by excessive protection is avoided, the problems that the junction temperature protection power in the prior art depends on experience setting and the safety and the power generation performance of the converter are difficult to be considered are effectively solved, and the self-optimization control of the junction temperature protection of the converter is realized.

Drawings

FIG. 1 is a schematic flow chart of a method for controlling synchronous speed segment operation of a wind turbine generator system in accordance with an embodiment of the present application;

FIG. 2 is a schematic flow chart of another method for controlling synchronous speed segment operation of a wind turbine generator system according to an embodiment of the present application;

Fig. 3 is a schematic structural diagram of a physical device of the generator control device according to an embodiment of the present application.

Detailed Description

The terminology used in the following embodiments of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the specification of the present application, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates to the contrary. It should also be understood that the term "and/or" as used in this disclosure is intended to encompass any or all possible combinations of one or more of the listed items.

The terms "first," "second," and the like, are used below for descriptive purposes only and are not to be construed as implying or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature, and in the description of embodiments of the application, unless otherwise indicated, the meaning of "a plurality" is two or more.

It should be noted that, the generator control device described herein, i.e. the control device, refers to a main controller PLC (Programmable Logic Controller ) of a wind turbine generator system in practical application, wherein the PLC is a digital operation electronic system designed specifically for application in an industrial environment, and it uses a type of programmable memory for storing programs therein, executing instructions facing users such as logic operation, sequential control, timing, counting, arithmetic operation, etc., and controlling various types of mechanical devices or production processes through digital or analog input/output.

In a control system architecture of the wind turbine generator, a PLC is located at a core dominant position, and is connected with control units of all subsystems such as a converter, a pitch system and a pitch system through buses or communication cables to be responsible for summarizing and coordinating an overall control strategy of the wind turbine generator. The PLC collects various signals such as wind speed, rotating speed, power, voltage, current and the like from the subsystem control unit, runs a preprogrammed control program, gives a series of control instructions, and respectively sends the control instructions to each subsystem for execution, so that the control of the whole processes such as start-stop, grid connection, power limiting, power control, fault protection and the like of the wind turbine generator is realized. Taking the current transformer as an example, the current transformer is usually provided with a separate current transformer controller, and specific functions such as PWM (Pulse Width Modulation ), current loop control and the like are performed, and the current transformer controller receives unified scheduling and power instructions of the PLC.

And real-time data exchange is carried out between the PLC and the converter controller through standard communication protocols such as industrial Ethernet, CAN bus and the like. And the PLC transmits the calculated key parameters such as the operation limiting power, the junction temperature protection power and the like to the converter controller through a communication cable. The converter controller adjusts PWM modulation proportion and on time of the switching tube according to the PWM modulation proportion, so that output voltage and active/reactive current of the converter are changed, and finally output power of the converter is accurately controlled and kept consistent with a PLC instruction. Meanwhile, the converter controller can report the junction temperature, capacitance voltage and other state quantities of the IGBT (Insulated Gate Bipolar Transistor ) to the PLC in time so as to facilitate the PLC to optimize the control scheme.

In the application scenario of the implementation, due to the cost control of the converter, when the wind generating set works in the synchronous rotation speed interval for a long time, the PWM switching frequency of the power device (such as IGBT) of the converter will become low, and the junction temperature of the low-cost converter power device will obviously rise when the switching frequency becomes low, and the power device will be damaged due to the overhigh junction temperature for a long time, so that the normal operation of the wind generating set is affected.

In the related art, in order to prolong the service life of the power device of the converter, the wind generating set is prevented from working in a synchronous rotation speed interval as long as possible. The related technology can directly lead the rotating speed of the wind generating set to span the synchronous rotating speed interval by pressing the rotating speed of the wind generating set to enable the rotating speed to be lower than the synchronous rotating speed interval and then releasing the rotating speed to be higher than the high rotating speed of the synchronous rotating speed interval after accumulation for a period of time, so as to ensure that the wind generating set cannot work in the synchronous rotating speed interval. However, the related art may have a part of wind energy wasted due to the process of suppressing the rotational speed, resulting in a decrease in the generation yield of the wind generating set.

By adopting the synchronous rotating speed section operation control method of the wind generating set, when the wind generating set generates electricity, whether the asynchronous generator is positioned in the synchronous rotating speed section or not can be judged according to the real-time rotating speed of the asynchronous generator, when the asynchronous generator is positioned in the synchronous rotating speed section, the junction temperature of a power device of the converter is monitored in real time, and when the junction temperature is too high, the junction temperature is reduced by reducing the actual limiting power, so that the damage of the power device is avoided; and meanwhile, the actual limited power is timely regulated after the junction temperature is recovered to be normal, so that the power generation loss is reduced.

Fig. 1 is a schematic flow chart of a synchronous speed segment operation control method of a wind turbine generator system according to an embodiment of the application.

S101, determining a synchronous rotating speed interval according to synchronous rotating speeds of asynchronous generators in the wind generating set and corresponding rotating speed tolerance percentages.

Wherein the synchronous speed n _s refers to the speed value of the asynchronous generator when the rotor speed is synchronous with the grid frequency, and is generally determined by the pole pair number of the asynchronous generator and the grid frequency, namelyWhere f is the frequency of the grid current and P is the pole pair number. The speed tolerance percentage n _tolp represents the value deviation range of the actual running speed of the asynchronous generator relative to the synchronous speed n _s, and is used for representing the width of the synchronous speed interval. The synchronous rotation speed interval refers to a rotation speed interval of the asynchronous generator in a certain range near the synchronous rotation speed, and when the real-time rotation speed n _c is positioned in the interval, namely n _s*(1-n_tolp)<n_c<n_s*(1+n_tolp), the wind turbine is considered to be in a quasi-synchronous operation state. For example, if the synchronous speed n _s is 1500rpm and the speed tolerance percentage n _tolp is 5%, the synchronous speed interval is 1425rpm to 1575rpm.

Specifically, the control device firstly obtains the rated synchronous rotating speed of the asynchronous generator of the wind turbine generator, and the rotating speed is determined by design parameters of the asynchronous generator and can be found in equipment initialization data such as factory data. The control device then sets a rotational speed tolerance percentage according to the actual application requirements, which is typically determined based on unit operation experience and efficiency optimization requirements. Finally, the control device calculates the upper and lower limit values of the synchronous rotation speed interval, namely the upper limit value n _s-up＝n_s*(1+n_tolp) and the lower limit value n _s-low＝n_s*(1-n_tolp by taking the synchronous rotation speed n _s as the center and combining the rotation speed tolerance percentage n _tolp. In the subsequent step, the interval is taken as a basis for judging whether the wind turbine generator is in a quasi-synchronous running state or not, and corresponds to different control strategies.

In some embodiments, the determination of the synchronous speed interval may be accomplished in a number of ways: optionally, the control device can directly call the factory parameters of the asynchronous generator to obtain the numerical value of the synchronous rotating speed n _s, then the operator manually inputs the tolerance percentage of the rotating speed according to experience, and the control device substitutes a formula to calculate the synchronous rotating speed interval; optionally, the control device can also access the equipment management system of the wind power plant to automatically acquire the synchronous rotation speed n _s and the rotation speed tolerance percentage parameter n _tolp of each wind turbine, and directly load the synchronous rotation speed n _s and the rotation speed tolerance percentage parameter n _tolp into the control logic. It will be appreciated that the setting of the synchronous rotation speed interval may be implemented in other manners, for example, by analyzing historical operation data of the wind turbine generator through big data, autonomously optimizing parameters of the synchronous rotation speed interval, etc., which are not limited herein.

S102, when the wind generating set generates wind energy, acquiring the real-time rotating speed of an asynchronous generator in the wind generating set.

The wind power generation is an operation process that wind energy is converted into electric energy and is transmitted to a power grid when the wind turbine generator is in a grid-connected state. The real-time rotating speed represents the current actual rotating speed of the rotor of the asynchronous generator, is usually measured in real time by a rotating speed sensor such as an encoder and the like and is used for representing the current running state of the wind turbine.

Specifically, the control device monitors the grid-connected state of the wind turbine at any time and judges whether the wind turbine is in the normal power generation process or not. When the wind turbine generator is in grid connection and power generation, the control device acquires the rotating speed feedback value of the rotor of the asynchronous generator in real time and takes the rotating speed feedback value as the real-time running rotating speed n _c of the wind turbine generator. The rotation speed signal is usually collected in real time by an encoder, a rotation speed sensor and other devices and transmitted to a control device, and the data sampling frequency can be set according to actual requirements, and is usually 10 times per second or higher. The obtained real-time rotating speed n _c can be used as a basic basis for judging whether the wind turbine enters the synchronous rotating speed interval in the subsequent step.

And S103, detecting the junction temperature of a power device of a converter in the wind generating set when the real-time rotating speed is in the synchronous rotating speed interval.

The junction temperature T _j of the power device refers to the actual working temperature of the power devices such as IGBTs in the current transformer, and is usually obtained by real-time measurement of a temperature sensor of the current transformer, and is used for indicating the heating state and the health level of the current transformer, and the maximum temperature value in each component is generally taken. The temperature sensor is generally tightly attached to the power device, and can accurately reflect the junction temperature change.

Specifically, the control device compares the asynchronous generator rotation speed n _c with the synchronous rotation speed interval (n _s-low,n_s-up) in real time, and judges whether the current rotation speed is positioned in the interval (n _s-low,n_s-up). Once the wind turbine enters the synchronous speed interval, the control device immediately triggers the temperature detection of the power device of the converter. The temperature sensor arranged in the converter is used for collecting the actual working temperature of the power devices such as the IGBT in real time and transmitting junction temperature data T _j to the control device. The junction temperature information obtained by the control device is used as a basis for judging whether the converter temperature rise protection needs to be started in the subsequent control step. The temperature detection process runs through the whole process of quasi-synchronous operation of the wind turbine generator so as to discover and treat the temperature rise risk of the converter in time.

In some embodiments, detection of the junction temperature of the converter power device may be achieved in a variety of ways: optionally, the control device can directly access the temperature sensor of the converter, and read junction temperature data in real time through a communication protocol; optionally, the control device can also establish a data link with the self-protection unit of the converter, and periodically acquire junction temperature information uploaded by the converter. It will be appreciated that other ways of detecting the temperature of the power device of the current transformer may be used, such as, but not limited to, installing an infrared thermometer outside the current transformer, remotely monitoring the surface temperature of the power device, etc.

And S104, storing the actual limiting power of the current wind generating set as the initial limiting power when the junction temperature of the power device is higher than the first protection threshold.

The first protection threshold T _j-up is a temperature threshold for triggering temperature rise protection of the power device of the converter, and is generally determined according to factors such as device material characteristics and design margin, and is used for indicating a temperature critical point at which protection measures are required for the converter to start to occur at the temperature rise risk. The initial limiting power P _lim1 refers to the actual limiting power P _c of the wind turbine generator set when the temperature rise protection of the converter is started, and reflects the maximum output capacity of the wind turbine generator set before the protection.

Specifically, the control device continuously monitors the junction temperature T _j of the power device of the current transformer, and compares the junction temperature with a preset first protection threshold T _j-up. When the junction temperature T _j exceeds the first protection threshold T _j-up, it indicates that the converter has a temperature rise risk, and protection control needs to be adopted. At this time, the control device will immediately record the actual limiting power of the current wind turbine and store it as the initial limiting power. The initial limiting power data is used as a power basis for recovering the normal operation of the wind turbine generator in the subsequent control step. It should be noted that the actual limiting power may be obtained through various approaches, for example, directly collecting the current active power given value of the wind turbine, or reading the corresponding parameters from the control system database, etc.

In some embodiments, the initial limit power for a wind turbine may be stored in a number of ways: optionally, the control device may create an initial limiting power table in the local database, write the current actual limiting power value into the table each time the temperature rise protection is triggered, and mark a corresponding time stamp; optionally, the control device may also use a cloud server to upload the initial limited power to a remote data center for unified storage and management. It will be appreciated that the storage of the initial limited power may also be accomplished in other ways, such as writing data to a non-volatile memory of the controller, such as EEPROM, flash, etc., without limitation.

S105, the actual limiting power is adjusted down to junction temperature protection power so as to reduce the junction temperature of the power device.

The junction temperature protection power P _j-safe is the maximum allowable output power of the wind turbine set for inhibiting the temperature rise of the converter, is generally lower than the rated power of the wind turbine set, is determined according to factors such as the heat dissipation condition and the temperature rise characteristic of the converter, and is used for representing the upper power limit of the wind turbine set in a protection state. And the actual limiting power P _c is regulated downwards, namely the maximum output power of the wind turbine generator is reduced, so that the heating value of the converter is reduced, and the purpose of inhibiting the temperature rise is achieved.

Specifically, when the junction temperature T _j of the power device of the current transformer exceeds the first protection threshold T _j-up, the control device immediately executes the power limiting protection. The control device firstly retrieves a preset junction temperature protection power value P _j-safe from the protection strategy library, and then sends the value to the control system of the wind turbine generator as new actual limiting power P _lim2. The wind turbine generator sets correspondingly reduce the output power according to the updated actual limiting power P _j-safe(P_lim2), and the active power set value of the converter is usually limited below junction temperature protection power P _j-safe(P_lim2). As the output power of the wind turbine generator decreases, the heating value of the power device of the converter also decreases, and the junction temperature T _j gradually falls back into the safety range until the temperature rise protection is released.

And S106, when the junction temperature of the power device is lower than a second protection threshold value, the actual limiting power of the wind generating set is returned to the initial limiting power.

The second protection threshold T _j-low is a temperature threshold for releasing the temperature rise protection of the power device of the converter, and the second protection threshold T _j-low is lower than the first protection threshold T _j-up and is determined according to factors such as the device temperature characteristic and the operation margin, and is used for indicating a temperature critical point at which the temperature rise risk of the converter is eliminated and normal operation can be restored. And (3) the actual limited power is regulated, namely the limited power protection is canceled, and the maximum output power of the wind turbine generator is recovered to the pre-protection level, so that the normal power generation capacity is recovered.

Specifically, after the converter enters the power limiting protection, the control device continuously monitors the change of the junction temperature T _j of the power device and compares the change with the second protection threshold T _j-low. When the junction temperature T _j is reduced to be below the second protection threshold T _j-low, the temperature rise risk of the converter is relieved, and the wind turbine generator can be restored to normal operation. At this time, the control device will terminate the power limiting protection, and read the initial limiting power P _lim1 of the wind turbine from the storage location, and forward the value to the wind turbine again to replace the junction temperature protecting power P _j-safe(P_lim2), so that the actual limiting power P _c of the wind turbine is returned to the pre-protecting level P _lim1.

In some embodiments, the callback of the actual limit power of the wind turbine may be implemented in a variety of ways: optionally, the control device may issue the difference between the initial limiting power P _lim1 and the junction temperature protecting power P _j-safe(P_lim2) as a power increasing instruction to the wind turbine generator, so as to gradually increase the output power to the initial level; optionally, the control device may also directly modify the power limiting parameter in the wind turbine generator system control system back to the initial value of the limiting power P _lim1 after the junction temperature T _j falls to the second protection threshold T _j-low. It will be appreciated that other manners of implementing the release of the power limit protection may be adopted, for example, the power limit may be gradually increased according to the real-time operation condition of the wind turbine, until the power is restored to the initial level, and the method is not limited herein.

In the above embodiment, the embodiment of the present application provides a method for controlling operation of a synchronous rotation speed segment of a wind turbine, where the method first determines a synchronous rotation speed segment, and monitors in real time whether the rotation speed of an asynchronous generator is located in the segment during the power generation process of the wind turbine; when the power device is positioned in the interval, the junction temperature T _j of the power device of the converter is further monitored and protected, the damage of the power device caused by overhigh junction temperature T _j is avoided, meanwhile, the actual limit power is timely adjusted back after the junction temperature T _j is recovered to be normal, and the power generation loss is reduced; and when the rotating speed of the asynchronous generator is not located in the synchronous rotating speed interval, the operation of the wind generating set can be controlled according to a normal power scheduling strategy.

In the actual implementation process, the callback of the power may involve various factors, if the callback method is improper, junction temperature early warning may be triggered quickly, so that the efficiency of the generator is low; especially when a wind generating set is limited in a certain power range due to grid instructions, how to reasonably control the power becomes a big problem. The method provided in this embodiment will be described in more detail. Fig. 2 is a schematic flow chart of a synchronous speed segment operation control method of a wind turbine generator system according to an embodiment of the application.

S201, determining a synchronous rotating speed interval according to synchronous rotating speeds of asynchronous generators in the wind generating set and corresponding rotating speed tolerance percentages.

Referring to step S101, the generator control apparatus determines a synchronous rotation speed interval.

S202, determining a power scheduling dead zone corresponding to the wind generating set according to the synchronous rotating speed interval.

The power scheduling dead zone refers to a power adjustment forbidden zone set for avoiding temperature rise and burnout of a power device of the converter when the wind turbine generator runs in quasi-synchronization, and generally corresponds to a synchronous rotating speed zone; when the output power is above the interval, the rotating speed of the generator is in the super-synchronous working area, so that the generator can work normally; when the output power is below the interval, the temperature rise of the power device of the converter is not obvious or is in an bearable range because of the smaller power.

Specifically, the control device calculates a power scheduling dead zone after determining the synchronous rotating speed interval of the wind turbine. Through the pre-established mapping relation between the synchronous rotating speed interval and the power scheduling dead zone, the control device can be quickly matched with the power scheduling dead zone range corresponding to the current wind turbine. The mapping relation is generally constructed based on rated parameters of the wind turbine generator, and a table lookup method is adopted to realize quick matching.

In some embodiments, the generator control means may determine the output power of the wind park at synchronous speed as a power dead zone centre; determining a power dead zone upper boundary P _up and a power dead zone lower boundary P _low according to the power tolerance percentage P _dp and the power dead zone center P _s to obtain a power scheduling dead zone; the power tolerance percentage is lower than the rotational speed tolerance percentage, i.e., P _dp<n_tolp.

The synchronous rotating speed refers to the rotating speed of a generator rotor when the wind generating set is in grid-connected operation, is usually determined by the frequency of a power grid and the pole pair number of the generator, and is used for representing the nominal operating rotating speed of the wind generating set in a grid-connected state. The power dead zone center refers to the output active power of the generator at the synchronous rotating speed, and represents the set output power of the wind turbine generator set at the standard synchronous rotating speed. The power tolerance percentage refers to the maximum percentage that allows the actual output power of the generator to deviate from the center of the power deadband for determining the width of the power scheduling deadband. The upper limit and the lower limit of the power dead zone respectively represent the upper limit value and the lower limit value of the power scheduling dead zone and are used for defining the effective range of scheduling limiting power issued by the power grid. For example, if the power dead zone center P _s is 1000kW and the power tolerance percentage P _dp is 3%, the power dead zone upper boundary P _up is 1030kW and the power dead zone lower boundary P _low is 970kW, and the interval between the two is the power scheduling dead zone.

Specifically, the generator control device determines the output power of the generator at the synchronous rotation speed and records the output power as the power dead zone center. Meanwhile, the control device reads a preset power tolerance percentage parameter from the local configuration file, and obtains two power values with the power dead zone center as a reference and the upper and lower offset tolerance percentages through multiplication and addition and subtraction calculation, wherein the two power values are respectively used as an upper power dead zone boundary and a lower power dead zone boundary. And the closed interval range defined by the upper and lower boundaries is the power scheduling dead zone autonomously determined by the generator control device. The dead zone represents an acceptable range of scheduled power for the wind turbine at nominal operating conditions. Notably, because the wind generating set adopts the power scheduling dead zone control, the tolerance percentage of the power dead zone interval is smaller than that of the synchronous rotating speed interval of the converter, the power scheduling dead zone range can be reduced to the maximum extent, and the wind generating set is favorable for being compatible with an upper energy management platform.

In some embodiments, the power scheduling dead zone may be determined in a number of ways: optionally, the generator control device can directly write fixed power dead zone center and tolerance percentage parameters by adopting a fixed value setting method before leaving a factory, and directly call the parameters to calculate the upper and lower boundaries of the dead zone during grid-connected operation; optionally, the generator control device can also adopt a self-learning method, in a grid-connected debugging stage, output power under the working condition of multiple synchronous rotating speeds is recorded, a power dead zone center is obtained through statistics, and then proper tolerance percentages are automatically matched, so that the upper and lower boundaries of the dead zone are finally obtained. It will be appreciated that other manners may be used to determine the power scheduling dead zone, such as an online optimization method, i.e. by establishing a static power-rotation speed model of the wind turbine, to solve the best dead zone parameter under the current working condition, which is not limited herein.

S203, acquiring scheduling limiting power issued by the power grid, and determining operation limiting power based on the scheduling limiting power and a power scheduling dead zone.

The scheduling limiting power P _g-lim refers to a maximum allowable output power instruction issued by a power grid scheduling mechanism to the wind turbine generator, and is generally determined according to factors such as real-time load level of the power grid and new energy consumption capacity and the like, and is used for representing the upper limit of the wind turbine generator for transmitting active power to the power grid. The operation limiting power P _lim refers to the maximum output power which can be actually executed by the wind turbine after the power scheduling dead zone constraint is considered, and is the comprehensive analysis result of the scheduling limiting power and the running state of the wind turbine, and is used for representing the real-time output power upper limit of the wind turbine.

Specifically, the control device periodically obtains the issued dispatching limit power value P _g-lim through a communication interface with the power grid dispatching mechanism, and the dispatching limit power value P _g-lim is used as the upper power limit of the wind turbine generator set. Meanwhile, the control device detects a power scheduling dead zone (P _low,P_up) of a single wind turbine in real time, and judges whether the power scheduling dead zone is in a power limiting regulation state or not. If the current operation power limit P _g-lim of the unit does not fall into the scheduling dead zone (P _low,P_up), taking the scheduling limit power P _g-lim as an operation limit power P _lim; if the current operating power limit P _g-lim of the unit is within the scheduling deadband (P _low,P_up), the limiting power P _lim is reduced to the power deadband lower bound P _low in order to avoid converter damage.

In some embodiments, the operational limiting power of a wind turbine may be determined in a number of ways: optionally, the control device can judge whether the scheduling limit power falls into a power scheduling dead zone through simple logic comparison, if so, the scheduling limit power is selected as the operation limit power, otherwise, the current power is locked; alternatively, the control device may also use a dynamic optimizing algorithm to search for the optimal operation limiting power on line with the power generation efficiency and the frequency modulation performance as objective functions. It will be appreciated that other manners of generating the operation limiting power may be adopted, for example, offline calculation of the optimal limiting power under various working conditions in advance, online direct table look-up acquisition, etc., which are not limited herein.

In some embodiments, the generator control device may acquire the scheduling limit power issued by the power grid, and determine whether the scheduling limit power is within a power scheduling dead zone range; if the scheduling limit power is not in the power scheduling dead zone range, taking the scheduling limit power as the operation limit power; and if the scheduling limit power is within the power scheduling dead zone range, taking the lower limit of the power dead zone as the operation limit power.

The scheduling limiting power P _g-lim refers to a maximum allowable output power instruction issued by a power grid scheduling mechanism for the wind turbine generator, is generally determined based on factors such as real-time load balance and new energy consumption capability of the power grid, and is used for controlling active output of the wind turbine generator to the power grid. The operation limiting power P _lim refers to a final limiting power set value adopted when the generator actually executes power control, not only considers the dispatching limiting power issued by the power grid, but also considers the safe and stable operation requirement of the wind turbine generator, and is used for guiding the control system to adjust the stable output power of wind wheel power, generator excitation and the like.

Specifically, the control command and the state information are transmitted in real time between the generator control device and the power grid dispatching master station through a communication line. When the power network issues new scheduling limit power, the generator control device immediately acquires the value and compares the value with an autonomously determined power scheduling dead zone. If the schedule limiting power is above the upper dead band limit or below the lower dead band limit, it indicates that the generator is outside the output power of the synchronous speed, i.e., in the safe output power range. At this time, the control device directly adopts the scheduling limiting power as the new operation limiting power and issues the new operation limiting power to the unit control system. The control system adjusts the pitch angle of the wind wheel, the exciting current of the generator and the like according to the wind angle, so that the output power of the wind turbine generator is tracked to the dispatching limit power quickly, and the dispatching requirement of the power grid is met. If the scheduling limit power falls within the dead zone range, the control device selects the dead zone lower limit as the new operation limit power, and the fault that the converter is excessively high in temperature caused by the excessively high power is avoided. After the control device issues the lower limit of the dead zone, the unit control system immediately starts power limiting control, and stable output power is not higher than the lower limit of the dead zone through adjusting the wind wheel and the generator, so that stable operation of the unit is ensured.

In some embodiments, the operation limiting power may be determined in a number of ways: optionally, the generator control device may adopt a static interval judgment method, that is, only comparing the magnitude relation between the scheduling limit power and the upper and lower boundaries of the dead zone, and accordingly selecting the scheduling limit power or the lower boundary of the dead zone as the final operation limit power; alternatively, the generator control device may also use a dynamic trend prediction method, i.e. continuously track the trend of the change of the scheduling limit power in a plurality of scheduling periods, and if it is predicted that the scheduling limit power will continuously exceed the dead zone for a period of time in the future, it is selected as the running limit power, otherwise, the dead zone lower limit value is still used. It will be appreciated that other ways of determining the operation limiting power may be used, such as introducing a machine learning algorithm, by analyzing historical operation data, autonomously deciding how to balance the relationship of scheduling limiting power and unit safety under different conditions, and is not limited herein.

S204, taking the operation limiting power as the actual limiting power, and controlling the wind generating set to generate wind energy.

The actual limiting power P _c refers to an upper limit of active power adopted by the wind turbine generator in actual control execution, and is generally determined by the operation limiting power P _lim, and is used for representing the real-time maximum power generation capacity of the wind turbine generator. The wind power generation is controlled by the wind power generation set, namely, the control system is required to adjust the operation parameters such as the pitch angle of the wind power generation set, the excitation of the generator, the reactive power of the converter and the like in real time according to the actual limiting power, and the output power of the wind power generation set is controlled within the actual limiting power, so that the wind energy is efficiently converted into electric energy and is transmitted to a power grid.

Specifically, the control device assigns the operation limiting power P _lim to an active power upper limit set value of the wind turbine control system, and the active power upper limit set value is used as the current actual limiting power P _c. And after the unit control system detects the actual limited power change, the corresponding tracking control strategy is started immediately. And the control system continuously monitors the real-time output power of the wind turbine generator set and compares the real-time output power with the actual limiting power by issuing a real-time control instruction to the variable pitch system and the converter. Once the real-time output power exceeds the limit power, the control system can quickly respond, adjust the pitch angle to reduce the wind wheel power, or adjust the running parameter of the converter to limit the output power of the generator, so as to ensure that the unit always runs stably within the actual limit power. Meanwhile, the control system feeds the measured power data of the wind turbine generator back to the control device in real time for subsequent control flow and state monitoring.

S205, acquiring the real-time rotating speed of an asynchronous generator in the wind generating set when the wind generating set generates wind energy.

Referring to step S102, the generator control device monitors the real-time rotational speed n _c of the wind turbine.

S206, detecting junction temperature of a power device of a converter in the wind generating set when the real-time rotating speed is in the synchronous rotating speed interval.

Referring to step S103, the generator control device monitors the junction temperature T _j of the power device of the converter.

And S207, storing the actual limiting power of the current wind generating set as the initial limiting power when the junction temperature of the power device is higher than a first protection threshold value.

Referring to step S104, the generator control device stores the initial limiting power P _lim1 when the junction temperature T _j of the power device is higher than the first protection threshold T _j-up.

S208, the actual limiting power is adjusted down to junction temperature protection power so as to reduce the junction temperature of the power device.

Referring to step S105, the generator control apparatus down-regulates the actual limiting power P _lim.

And S209, when the junction temperature of the power device is lower than a second protection threshold value, acquiring a power difference value between junction temperature protection power P _j-safe and initial limiting power.

The power difference Δp represents the difference between the junction temperature protection power P _j-safe(P_lim2) and the initial limiting power P _lim1, and reflects the reduced power generation capacity of the wind turbine during the converter temperature rise protection.

Specifically, after the wind turbine generator system executes junction temperature protection power P _j-safe(P_lim2), the control device continuously monitors the junction temperature change of the power device of the converter. When the junction temperature T _j is reduced below the second protection threshold T _j-low, the risk of temperature rise of the converter is basically eliminated, and the wind turbine generator can gradually recover normal running power. The control device subtracts the current junction temperature protection power P _j-safe(P_lim2) from the previously stored initial limiting power P _lim1 to obtain a power difference lost during protection. The power difference data are used in the subsequent control step to generate callback instructions for gradually recovering the power generation capacity of the wind turbine generator. Meanwhile, the control device also restores the junction temperature T _j of the converter to the state information of the safety level and feeds the state information back to the wind power plant monitoring system so that operation and maintenance personnel can know the latest running state of the unit.

S210, dividing the power difference value into a plurality of ordered power callback segments according to a preset power step length.

The power step length Δp _i refers to the power amplitude added each time in the process of gradually recovering the power generation capacity of the wind turbine generator, and is generally set according to factors such as the regulation capacity of the wind turbine generator and the grid connection requirement of the power grid, and is used for controlling the rate and granularity of gradually releasing the power of the wind turbine generator. The power callback segment P _i refers to dividing the power difference into a plurality of continuous power intervals, and each interval corresponds to a power callback operation and is used for representing an execution step of gradually recovering the power generation capacity of the wind turbine generator.

Specifically, the control device immediately starts calculation of the power callback segment after obtaining the power difference value caused by junction temperature protection. According to the preset power step length, the control device divides the power difference value into a plurality of equal or regular power intervals, and the width of each interval is the size of the power step length.

For example, if the power difference Δp is 100kW and the power step Δp _i is 0.2, then it may be divided into 5 sequential power callback segments P _i, 20kW. The sequence of segments is arranged in such a way that starting from the junction temperature protection power P _j-safe(P_lim2), one power step at a time is increased by 20kW until the initial limit power P _lim1 is reached. For another example, a regular power interval can be set, if the power difference Δp is 100kW, and the preset power step Δp _i is 0.2, 0.6 or 0.2, then 100kW can be divided into 3 ordered power callback segments P _i, namely 20kW, 60kW and 20kW, through the rule, 60kW can be directly callback after 20kW callback is detected to be effective, callback efficiency is ensured, and the regular division of the preset power step can be set and adjusted by staff or background developers; in some embodiments, the preset power step size may also be set to 0.6, 0.2 or 0.2, 0.6, etc.

S211, adding a power callback segment for the actual limited power according to the arrangement sequence of the plurality of ordered power callback segments.

Wherein the actual limiting power P _lim has been down-regulated to the junction temperature protection power P _j-safe(P_lim2 at the junction temperature protection time). Sequentially increasing a power callback segment P _i, that is, starting from junction temperature protection power P _j-safe(P_lim2), each time, the actual limiting power P _lim is gradually increased according to the sequence of the power callback segments until the initial limiting power P _lim1 is finally recovered.

Specifically, the control device immediately starts a control flow for gradually recovering the power generation capacity of the wind turbine after generating the ordered power callback segments. First, the control device reads the first segment value of the power callback segment sequence, and adds it to the current actual limiting power (i.e. junction temperature protection power P _j-safe(P_lim2)) to obtain a new actual limiting power value. The control device transmits the new actual limiting power to the wind turbine generator control system, and synchronously updates the locally recorded actual limiting power parameters. After the set control system receives the new power limiting set value, a power limiting control strategy is started, wind wheel power input is gradually increased or generator excitation is regulated, so that the upper power output limit of the wind turbine can be stably increased, and finally, the actual limit power value after a callback section is newly increased is stabilized.

In some embodiments, the piecewise callback of the actual limited power may be implemented in a number of ways: alternatively, the control device may use a timing trigger manner, and increase a callback segment for the actual limiting power every fixed time period until the initial limiting power P _lim1 is reached.

And S212, if the junction temperature increment of the junction temperature of the power device is not higher than a preset abnormal threshold value in the preset test time, adding a next power callback section for the actual limiting power until the actual limiting power reaches the initial limiting power.

The preset test time is an observation time period set for evaluating the change of the junction temperature T _j of the power device of the converter after the actual limiting power is increased each time, and is generally determined based on the dynamic characteristics of the heat dissipation system of the converter, and is used for judging whether the current callback segment can cause the junction temperature T _j to exceed the standard again. The preset abnormal threshold value refers to a temperature change amplitude value triggering abnormal junction temperature, and is generally set based on factors such as a second protection threshold value T _j-low and a temperature control margin of the converter, and is used for representing a critical temperature rise rate of the current callback section, wherein the critical temperature rise rate possibly causes temperature rise risk of the converter again, of the power level corresponding to the current callback section. The junction temperature increment is the maximum increment value of the temperature of the power device of the converter in the preset test time.

Specifically, the control device initiates the junction temperature impact assessment immediately after each increase of one callback segment P _i to the actual limit power. And continuously collecting junction temperature data of the power device of the converter in a preset test time by the control device, calculating the maximum added value of the junction temperature T _j during the test, and comparing the maximum added value with a preset abnormal threshold value. If the junction temperature increment is not higher than the abnormal threshold value, the current practical limit power level is not challenging to heat dissipation of the converter, and the output of the wind turbine generator can be continuously improved. The control device will read the next segment value of the power callback segment sequence, repeat the control action of S211, and increase the actual limiting power again. According to the rule, the control device continuously increases a plurality of callback segments to realize the stepwise increase of the actual limiting power until the initial limiting power P _lim1 is restored.

In some embodiments, the junction temperature impact of the power callback procedure may be monitored in a number of ways: optionally, the control device can judge whether the junction temperature increment exceeds an abnormal threshold value through simple threshold value comparison, so as to determine whether to continuously increase the actual limiting power; optionally, the control device may deploy a junction temperature prediction model, and after adding a callback segment, predict the future change trend of the junction temperature T _j in real time, and take control measures in advance.

In some embodiments, the generator control device records the time when the actual limiting power is returned to the initial limiting power P _lim1 as the first time t ₁; obtaining time when the junction temperature T _j of the power device is higher than the first protection threshold T _j-up again, wherein the time is second time T ₂; when the time difference Δt between the second time t ₂ and the first time t ₁ is lower than the preset time difference Δt ₀, the junction temperature protection power P _j-safe is adjusted based on the preset protection rule.

The first time t ₁ represents a time when the actual limiting power of the wind generating set is restored to the initial limiting power P _lim1 before protection for the first time after the junction temperature protection of the converter is finished, and is used for identifying a starting point of the complete return of the output power of the wind generating set to the normal level. The second time T ₂ is the time when the junction temperature of the power device of the converter exceeds the first protection threshold T _j-up again after the recovery, and indicates the time point when the unit enters the temperature rise risk state of the converter again. The preset time difference Δt ₀ refers to the minimum interval between two key time points for triggering adjustment of the junction temperature protection power P _j-safe, and is generally determined based on the thermal characteristic time constant of the heat dissipation system of the converter. When the interval between the second time T ₂ and the first time T ₁ is smaller than the preset threshold, which means that the wind turbine generator system just resumes the normal operation power for a short time, the converter junction temperature T _j enters the high risk area again, and the original junction temperature protection power P _j-safe parameter may be higher, and needs to be further reduced to inhibit the junction temperature rebound. The preset protection rule refers to a series of decision logic and control strategies for adjusting the junction temperature protection power P _j-safe when the junction temperature T _j repeatedly exceeds the standard, and generally includes reducing the amplitude coefficient of the protection power, shortening the execution time of the protection power, increasing the duration time of the protection power, and the like, for example, reducing the junction temperature protection power by 10kW, shortening the junction temperature protection response to within 5s, increasing the junction temperature protection time by 10min, and the like, which can be used for enhancing the over-temperature protection effect of the converter.

Specifically, the generator control device records the current time stamp immediately after successfully recovering the power level of the wind turbine generator set, and the current time stamp is used as the first time t ₁. This time stamp marks the end of the thermal protection state of the unit and returns to normal operation under the control of the initial limiting power P _lim1. However, the control device still continuously monitors junction temperature data of the power device of the converter, and once the junction temperature value T _j is found to exceed the first protection threshold T _j-up again, immediately triggers a new junction temperature protection process, and records the current time stamp as the second time T ₂. The control device subtracts the second time t ₂ from the first time t ₁ to obtain an actual time interval Δt between two junction temperature exceeding events, and compares the actual time interval Δt with a preset time difference threshold Δt ₀. If the actual interval is smaller than the preset threshold, the effect of the scheme of the junction temperature protection power P _j-safe executed before is poor, and the method is insufficient for inhibiting the rebound of the junction temperature of the converter for a long time. At this time, the control device will call a preset protection rule to adjust the current junction temperature protection power P _j-safe. For example, the calculation coefficient of the junction temperature protection power P _j-safe can be further reduced from 90% to 80% to obtain a lower new protection power value; and the duration of the new protection power is prolonged from 5 minutes to 10 minutes to delay the process of recovering the normal power. The adjusted new protection power schemes are issued to the unit control system again for restarting the power limiting protection, so that the output level of the wind turbine unit and the heating power of the converter are further reduced, and the hidden danger that the junction temperature T _j exceeds the standard repeatedly is thoroughly eliminated.

In some embodiments, the adjustment of junction temperature protection power P _j-safe may be triggered in a variety of ways: optionally, the generator control device may adopt a fixed interval triggering method, that is, after junction temperature protection, if junction temperature T _j is detected to exceed the standard again within a fixed time interval, a preset protection rule is started to adjust protection power, otherwise, the original protection scheme is maintained unchanged; optionally, the generator control device can also adopt a self-adaptive interval triggering method, namely, the triggering interval of the twice junction temperature exceeding is dynamically shortened according to the frequency and the amplitude of the junction temperature exceeding, and meanwhile, the adjustment strategy of the protection power is optimized in real time. It can be appreciated that other manners may be used to trigger adjustment of the junction temperature protection power P _j-safe, for example, in combination with external environmental factors such as weather forecast, and actively adjust the junction temperature protection power P _j-safe under special conditions such as high temperature or fixed wind speed to prevent temperature rise risk, which is not limited herein.

And S213, if the junction temperature increment of the junction temperature of the power device is higher than a preset abnormal threshold value in the preset test time, reducing the last power callback section for the actual limiting power until the actual limiting power reaches the junction temperature protection power.

The junction temperature increment is higher than an abnormal threshold value, which indicates that the current practical limiting power of the wind turbine generator set obviously aggravates the heat dissipation pressure of the power device of the converter, the junction temperature T _j begins to rise in an accelerating way, the risk of new temperature rise can be caused, and power back-down measures need to be taken in time. The last power callback segment is reduced, namely the actual limiting power is gradually reduced according to the reverse order of the callback segments, and one callback segment is reduced each time until the junction temperature protection power P _j-safe falls back.

Specifically, when the control device monitors that the junction temperature increment exceeds the abnormal threshold value in the test period of a certain callback section, the power callback flow is immediately interrupted. The control device subtracts the callback segmentation value added in the last step from the latest actual limiting power to retrieve the reduced actual limiting power. The new actual limiting power is issued to the wind turbine control system while the local record of the control device is updated. The set control system obtains the reduced power limit set value, the power limit control is started again, the wind wheel power input is reduced or the generator excitation is regulated down, the active output of the wind turbine is enabled to be steadily reduced, and finally the actual limit power value after a callback section is reduced is stabilized. If the new actual limiting power is still higher than the junction temperature protection power P _j-safe, the control will continue to monitor the junction temperature change, and again reduce the callback segment if necessary, until the actual limiting power falls back to the original junction temperature protection power P _j-safe level.

In the embodiment of the application, the synchronous rotating speed interval is determined according to the synchronous rotating speed of the asynchronous generator in the wind generating set and the corresponding rotating speed tolerance percentage, when the real-time rotating speed is positioned in the synchronous rotating speed interval, the junction temperature T _j of the power device of the converter in the wind generating set is detected, when the junction temperature T _j of the power device is higher than the first protection threshold T _j-up, the actual limiting power of the current unit is stored as the initial limiting power P _lim1, and the actual limiting power is downwards regulated to the junction temperature protection power P _j-safe, so that the junction temperature T _j of the power device is reduced, when the junction temperature T _j of the power device is too high, the junction temperature T _j of the power device is reduced by reducing the actual limiting power of the wind generating set, the problem that the power device is damaged due to the fact that the junction temperature T _j is too high is effectively solved, and the power loss of the converter power device is avoided, and the generating loss of the unit is reduced. Meanwhile, when the junction temperature T _j of the power device is lower than the second protection threshold T _j-low, the actual limiting power of the wind generating set is gradually adjusted back to the initial limiting power P _lim1 in a sectionalized mode, so that after the junction temperature T _j of the power device is recovered to be normal, the actual limiting power of the wind generating set can be stably and safely recovered, the problem that the output power of the wind generating set suddenly changes due to the fact that the rotating speed is directly released in the related art is effectively solved, and further the wind generating set is regulated more stably and controllably.

Next, a description will be given of a generator control device in an embodiment of the present application from the perspective of hardware processing, and please refer to fig. 3, which is a schematic structural diagram of a physical device of the generator control device in an embodiment of the present application.

It should be noted that the structure of the generator control device shown in fig. 3 is only an example, and should not impose any limitation on the functions and the application scope of the embodiment of the present invention.

As shown in fig. 3, the generator control apparatus includes a central processing unit (Central Processing Unit, CPU) 301 that can perform various appropriate actions and processes, such as performing the methods described in the above embodiments, according to a program stored in a Read-Only Memory (ROM) 302 or a program loaded from a storage section 308 into a random access Memory (Random Access Memory, RAM) 303. In the RAM 303, various programs and data required for the system operation are also stored. The CPU 301, ROM 302, and RAM 303 are connected to each other through a bus 304. An Input/Output (I/O) interface 305 is also connected to bus 304.

The following components are connected to the I/O interface 305: an input section 306 including an audio input device, a push button switch, and the like; an output portion 307 including a Liquid crystal display (Liquid CRYSTAL DISPLAY, LCD), an audio output device, an indicator lamp, and the like; a storage section 308 including a hard disk or the like; and a communication section 309 including a network interface card such as a LAN (Local Area Network ) card, a modem, or the like. The communication section 309 performs communication processing via a network such as the internet. The drive 310 is also connected to the I/O interface 305 as needed. A removable medium 311 such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, or the like is installed on the drive 310 as needed, so that a computer program read therefrom is installed into the storage section 308 as needed.

In particular, according to embodiments of the present invention, the processes described above with reference to flowcharts may be implemented as computer software programs. For example, embodiments of the present invention include a computer program product comprising a computer program embodied on a computer readable medium, the computer program comprising a computer program for performing the method shown in the flowchart. In such an embodiment, the computer program may be downloaded and installed from a network via the communication portion 309, and/or installed from the removable medium 311. When the computer program is executed by a Central Processing Unit (CPU) 301, various functions defined in the present invention are performed.

Specific examples of the computer-readable storage medium include, but are not limited to: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-Only Memory (ROM), an erasable programmable read-Only Memory (Erasable Programmable Read Only Memory, EPROM), a flash Memory, an optical fiber, a portable compact disc read-Only Memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present invention. Where each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures.

Specifically, the generator control device of the embodiment includes a processor and a memory, where the memory stores a computer program, and when the computer program is executed by the processor, the synchronous speed segment operation control method of the wind turbine generator set provided in the embodiment is implemented.

As another aspect, the present invention also provides a computer-readable storage medium that may be included in the generator control apparatus described in the above embodiment; or may be present alone without being incorporated into the generator control device. The storage medium carries one or more computer programs which, when executed by a processor of the generator control device, cause the generator control device to implement the synchronous speed segment operation control method of the wind turbine generator set provided in the above embodiment.

The above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the application.

As used in the above embodiments, the term "when …" may be interpreted to mean "if …" or "after …" or "in response to determination …" or "in response to detection …" depending on the context. Similarly, the phrase "at the time of determination …" or "if detected (a stated condition or event)" may be interpreted to mean "if determined …" or "in response to determination …" or "at the time of detection (a stated condition or event)" or "in response to detection (a stated condition or event)" depending on the context.

Those of ordinary skill in the art will appreciate that implementing all or part of the above-described method embodiments may be accomplished by a computer program to instruct related hardware, the program may be stored in a computer readable storage medium, and the program may include the above-described method embodiments when executed. And the aforementioned storage medium includes: ROM or random access memory RAM, magnetic or optical disk, etc.

Claims

1. A method for controlling operation of synchronous rotating speed segments of a wind generating set, which is applied to a generator control device, the method comprising:

Determining a synchronous rotating speed interval according to the synchronous rotating speed of the asynchronous generator in the wind generating set and the corresponding rotating speed tolerance percentage;

when the wind generating set generates wind energy, acquiring the real-time rotating speed of the asynchronous generator in the wind generating set;

Detecting the junction temperature of a power device of a converter in the wind generating set when the real-time rotating speed is in the synchronous rotating speed interval;

When the junction temperature of the power device is higher than a first protection threshold value, storing the actual limiting power of the wind generating set as the initial limiting power; the actual limiting power is the maximum output power set in the current running process of the wind generating set, and the default value of the actual limiting power is the rated power of the set;

The actual limiting power is adjusted down to junction temperature protection power so as to reduce the junction temperature of the power device;

And when the junction temperature of the power device is lower than a second protection threshold value, the actual limiting power of the wind generating set is returned to the initial limiting power.

2. The method according to claim 1, wherein said step of bringing back said actual limiting power of said wind power plant to said initial limiting power when said power device junction temperature is below a second protection threshold, comprises in particular:

when the junction temperature of the power device is lower than a second protection threshold value, acquiring a power difference value between the junction temperature protection power and the initial limiting power;

dividing the power difference value into a plurality of ordered power callback segments according to a preset power step length;

adding a power callback segment to the actual limited power according to the arrangement sequence of the plurality of ordered power callback segments;

If the junction temperature increment of the junction temperature of the power device is not higher than a preset abnormal threshold value in the preset test time, the next power callback section is added for the actual limiting power until the actual limiting power reaches the initial limiting power.

3. The method of claim 2, wherein after the step of adding one power callback segment to the actual limited power in the order of the plurality of ordered power callback segments, the method further comprises:

If the junction temperature increment of the junction temperature of the power device is higher than a preset abnormal threshold value in the preset test time, the last power callback section is reduced for the actual limiting power until the actual limiting power reaches the junction temperature protection power.

4. The method according to claim 1, wherein after the step of determining a synchronous speed interval from the synchronous speed of the asynchronous generator in the wind power plant and the corresponding speed tolerance percentage, the method further comprises:

determining a power scheduling dead zone corresponding to the wind generating set according to the synchronous rotating speed interval;

acquiring scheduling limiting power issued by a power grid, and determining operation limiting power based on the scheduling limiting power and the power scheduling dead zone;

and taking the operation limiting power as the actual limiting power, and controlling the wind generating set to generate wind energy.

5. The method according to claim 4, wherein the determining the power scheduling dead zone corresponding to the wind generating set according to the synchronous rotation speed interval specifically includes:

Determining the output power of the wind generating set at the synchronous rotating speed as a power dead zone center;

Determining a power dead zone upper bound and a power dead zone lower bound according to the power tolerance percentage and the power dead zone center to obtain a power scheduling dead zone; the power tolerance percentage is lower than the rotational speed tolerance percentage.

6. The method according to claim 5, wherein the obtaining the scheduling constraint power issued by the power grid, and determining the operation constraint power based on the scheduling constraint power and the power scheduling dead zone, specifically comprises:

acquiring scheduling limiting power issued by a power grid, and determining whether the scheduling limiting power is within the power scheduling dead zone range;

If the scheduling limit power is not in the power scheduling dead zone range, taking the scheduling limit power as an operation limit power;

and if the scheduling limit power is within the power scheduling dead zone range, taking the power dead zone lower bound as the operation limit power.

7. The method according to claim 1, wherein after the step of recalling the actual limiting power of the wind power plant to the initial limiting power when the power device junction temperature is below a second protection threshold, the method further comprises:

recording the time when the actual limiting power is returned to the initial limiting power as the first time;

Obtaining the time when the junction temperature of the power device is higher than the first protection threshold again, wherein the time is the second time;

And when the time difference between the second time and the first time is lower than a preset time difference, adjusting the junction temperature protection power based on a preset protection rule.

8. A generator control apparatus, characterized by comprising: one or more processors and memory; the memory is coupled with the one or more processors, the memory for storing computer program code comprising computer instructions that the one or more processors invoke to cause the generator control device to perform the method of any of claims 1-7.

9. A computer readable storage medium comprising instructions which, when run on a generator control device, cause the generator control device to perform the method of any of claims 1-7.

10. A computer program product, characterized in that the computer program product, when run on a generator control device, causes the generator control device to perform the method according to any one of claims 1-7.