KR20200134766A - Method and apparatus for driving motor and compressor including the same - Google Patents

Abstract

The present invention relates to a compressor, and more particularly, to a motor driving apparatus and a driving method thereof, and a compressor including the same. The present invention provides a method for controlling a motor using an inverter, comprising: applying a current to forcibly align and start the motor at a first magnetic flux angle; Estimating the speed and magnetic flux angle of the motor; Comparing the estimated magnetic flux angle with the first magnetic flux angle; Compensating for an error between the estimated magnetic flux angle and the first magnetic flux angle; And driving the motor according to the magnetic flux angle for which the error is compensated.

Description

TECHNICAL FIELD [Method and apparatus for driving motor and compressor including the same}

The present invention relates to a compressor, and more particularly, to a motor driving apparatus capable of preventing an initial starting failure of the motor, a driving method thereof, and a compressor including the same.

A scroll type compressor is a type of compressor capable of compressing a fluid such as a refrigerant while a fixed scroll is fixed in an inner space of a sealed casing, and a orbiting scroll is engaged with the fixed scroll to perform orbital motion.

These scroll type compressors can obtain a relatively high compression ratio compared to other types of compressors, and also have the advantage of obtaining stable torque by smoothly continuing the suction, compression and discharge processes of fluids, so they are widely used for refrigerant compression in air conditioners, etc. Is being used.

A compressor including such a scroll type compressor can be operated by driving a motor by an inverter.

Since such a motor does not have a sensor, it is impossible to know the initial position of the rotor. In order to drive a permanent magnet synchronous motor without a sensor, the motor is forcibly aligned and the actual speed of the rotor cannot be known without the position information of the rotor. Therefore, a current controller can be used without using a speed controller for initial driving.

At this time, when the current controller is converted to a sensorless speed controller, an overshoot of the rotor speed and current may occur due to an error between the rotor position used in the current controller and the rotor position used in the speed controller.

In addition, in a compressor using a gaseous refrigerant, the actual applied load cannot be accurately known, so the command current of the initial current controller must be set large. If the rotor position is not compensated after switching, the overshoot of the speed and current occurs largely. As a result, the position information (magnetic flux angle) of the rotor may not be accurately estimated.

In addition, due to the overshoot of the current and failure to accurately estimate the position information (magnetic flux angle) of the rotor, the probability of the motor starting failure may increase.

The technical problem to be achieved by the present invention is to solve the above problems, a driving device for a motor capable of preventing overshoot of current when switching to a sensorless algorithm when the motor is initially started, and a driving method thereof, and the same It is intended to provide a compressor including.

In addition, it is an object to provide a motor driving apparatus and a driving method and a compressor including the same capable of minimizing starting failure when the motor is initially started.

In order to solve the above problems, the present invention is a motor that controls a constant speed through current control in a low speed and low torque region, and then switches to sensorless speed control, and compensates for the error in the magnetic flux angle at this time. It is intended to provide a driving device and a driving method thereof.

Through this, the present invention proposes an improved switching technique that can reduce current over shoot that occurs when switching from current control to sensorless speed control and minimize motor startup failure.

As a specific example, the present invention provides a method for controlling a motor using an inverter, comprising: forcibly aligning and starting the motor at a first magnetic flux angle by applying a current; Estimating the speed and magnetic flux angle of the motor; Comparing the estimated magnetic flux angle with the first magnetic flux angle; Compensating for an error between the estimated magnetic flux angle and the first magnetic flux angle; And driving the motor according to the magnetic flux angle for which the error is compensated.

In addition, the forcibly aligning and starting may include applying a dc current and an ac current to the motor.

In addition, in the step of applying the dc current, a dc current corresponding to an electric angle of 0 degrees may be applied to the d-axis of the dq synchronous coordinate system.

In addition, the step of estimating the speed and the magnetic flux angle of the motor may be performed using the back electromotive force generated in the forced alignment step.

In addition, in the step of forcibly aligning and starting, a positive current may be applied to the d-axis of the dq synchronous coordinate system and a current of zero magnitude may be applied to the q-axis.

In addition, in the driving of the motor, when an error between the estimated magnetic flux angle and the first magnetic flux angle is less than or equal to a set value, the motor may be driven according to the magnetic flux angle for which the error is compensated.

As another specific example, the present invention, the motor; An inverter for driving the motor; A current sensing unit sensing the output current of the inverter; And an inverter control unit for controlling the inverter, wherein the inverter control unit includes: a current controller for forcibly aligning and starting the motor at a first magnetic flux angle by applying a current; A speed and position estimation unit that estimates the speed and magnetic flux angle of the motor; An error compensator for compensating for an error between the estimated magnetic flux angle and the first magnetic flux angle by comparing the estimated magnetic flux angle with the first magnetic flux angle.

In addition, the current controller may apply a dc current and an ac current to the motor.

In addition, the current controller may apply a dc current corresponding to an electric angle of 0 degrees to the d-axis of the dq synchronous coordinate system.

In addition, the speed and position estimating unit may estimate the speed and magnetic flux angle of the motor using the back electromotive force generated during the process of forcibly aligning and starting the current controller.

Further, the current controller may apply a positive current to the d-axis of the dq synchronous coordinate system and apply a current of zero magnitude to the q-axis.

In addition, when an error between the estimated magnetic flux angle and the first magnetic flux angle is less than or equal to a set value, the inverter controller may drive the motor according to the magnetic flux angle for which the error is compensated by the error compensation unit.

As another specific example, the present invention may provide a compressor including a driving device having the characteristics as described above.

The present invention has the following effects.

First, according to the present invention, it is possible to reduce a current over shoot that may occur when switching from current control of a motor to sensorless speed control, thereby minimizing a failure to start the motor.

Further scope of applicability of the present invention will become apparent from the detailed description below. However, since various changes and modifications within the spirit and scope of the present invention can be clearly understood by those skilled in the art, specific embodiments such as the detailed description and preferred embodiments of the present invention should be understood as being given by way of example only.

1 is a block diagram of a drive device for driving a motor according to an embodiment of the present invention.
2 is a flow chart showing a method of driving a motor according to an embodiment of the present invention.
3 is a graph showing a d-axis current command value according to a motor driving apparatus and a driving method thereof according to an embodiment of the present invention.
4 is a graph showing a q-axis current command value according to a motor driving apparatus and a driving method thereof according to an embodiment of the present invention.
5 is a graph showing an error compensation process according to a motor driving apparatus and a driving method thereof according to an embodiment of the present invention.
6 is a graph showing an applied current according to a motor driving apparatus and a driving method thereof according to an embodiment of the present invention.
7 is a waveform diagram showing a current waveform when magnetic flux angle compensation is not performed.
8 is a waveform diagram showing a current waveform according to a motor driving apparatus and a driving method thereof according to the present invention.
9 is a cross-sectional view showing a compressor to which the present invention can be applied.

Hereinafter, exemplary embodiments disclosed in the present specification will be described in detail with reference to the accompanying drawings, but identical or similar elements are denoted by the same reference numerals regardless of reference numerals, and redundant descriptions thereof will be omitted. The suffixes "module" and "unit" for components used in the following description are given or used interchangeably in consideration of only the ease of preparation of the specification, and do not have meanings or roles that are distinguished from each other by themselves. In addition, in describing the embodiments disclosed in the present specification, when it is determined that a detailed description of related known technologies may obscure the subject matter of the embodiments disclosed in the present specification, the detailed description thereof will be omitted. In addition, the accompanying drawings are for easy understanding of the embodiments disclosed in the present specification, and the technical idea disclosed in the present specification is not limited by the accompanying drawings, and all modifications included in the spirit and scope of the present invention It should be understood to include equivalents or substitutes.

Terms including ordinal numbers, such as first and second, may be used to describe various elements, but the elements are not limited by the terms. These terms are used only for the purpose of distinguishing one component from another component.

When a component is referred to as being "connected" or "connected" to another component, it is understood that it may be directly connected or connected to the other component, but other components may exist in the middle. Should be. On the other hand, when a component is referred to as being "directly connected" or "directly connected" to another component, it should be understood that there is no other component in the middle.

Singular expressions include plural expressions unless the context clearly indicates otherwise.

In the present application, terms such as "comprises" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance.

1 is a block diagram of a drive device for driving a motor according to an embodiment of the present invention.

Referring to FIG. 1, a driving device for driving the motor 200 is, largely, an inverter 210 that drives the motor 200 by outputting a driving signal to the motor 200, and controls the inverter 210 It may include an inverter control unit 100.

When the speed and position of the motor 200 are estimated, the driving device includes a sensorless driving unit 300 and 310 that can control the rotational speed of the motor 200 according to the estimated speed and position. It may contain more. These sensorless driving units 300 and 310 may be a component included in the inverter control unit 100.

Here, the motor 200 may be a synchronous motor. Synchronous motor refers to a motor that rotates by following the rotor according to the magnetic field created by the stator. In other words, it refers to a motor that rotates in synchronization with the directions of the magnetic flux of the stator and the rotor. Hereinafter, the motor 200 means a synchronous motor. However, the present invention is not limited thereto.

The inverter controller 100 may include a control switching unit 110 having a predetermined frequency and size or outputting a target current according to a speed command.

When the motor 200 is initially driven, the control switching unit 110 outputs a current having a predetermined frequency and size by open loop control (I/F control) or a sensorless driving unit 300, The target current according to the speed command can be output from 310).

That is, the control conversion unit 110 switches whether to drive the motor 200 by initial open loop control of the motor 200 or to drive the motor 200 by sensorless control after the motor 200 is synchronized. can do.

The inverter controller 100 may include a current controller 120 that generates a target voltage based on the target current output from the control conversion unit 110.

A voltage command is output from the current controller 120, and the voltage command is transmitted to the inverter 210, and the inverter 210 may generate a driving signal according to the voltage command.

In this case, the driving signal may be a pulse width modulation (PWM) signal.

That is, the inverter (PWM inverter) 210 includes a plurality of switching elements, and the switching elements may be operated by a PWM signal to generate an AC waveform.

A current sensing unit 220 may be provided between the inverter 210 and the motor 200. The current sensing unit 220 may detect the output current of the inverter 210.

The inverter control unit 100 applies a current to the current controller 120 forcibly aligning and starting the motor 200 at a first magnetic flux angle, and a speed and position estimation unit 310 that estimates the speed and magnetic flux angle of the motor 200. ), and comparing the magnetic flux angle estimated by the speed and position estimation unit 310 with the first magnetic flux angle, and compensating for an error between the estimated magnetic flux angle and the first magnetic flux angle.

In this case, the speed and position estimating unit 310 may be used even after sensorless conversion is made, and may be regarded as a part of a sensorless driving unit.

The current controller 120 of the inverter controller 100 may apply a dc current and an ac current to the motor 200.

At this time, the current controller 120 may apply a dc current corresponding to an electric angle of 0 degrees to the d-axis of the dq synchronous coordinate system.

In addition, the speed and position estimating unit 310 may estimate the speed and magnetic flux angle of the motor 200 using the back electromotive force generated in the process of forcibly aligning and starting the current controller 120.

That is, the speed and position estimating unit 310 may estimate the speed and magnetic flux angle of the motor 200 by using the output of the current sensing unit 220 that senses the output current of the inverter 210.

The current controller 120 may apply a positive current to the d-axis of the dq synchronous coordinate system, and may also apply a current of zero magnitude to the q-axis.

At this time, specifically, the current controller 120 may apply a dc current to the motor 200, and then, may apply an ac current having the same magnitude as the dc current.

As mentioned above, the error compensating unit 130 may compensate for an error between the estimated magnetic flux angle and the first magnetic flux angle by comparing the magnetic flux angle estimated by the speed and position estimation unit 310 with the first magnetic flux angle. .

At this time, the error compensating unit 130 may compensate for the error by reducing the d-axis current to negative and increasing the q-axis current to positive.

That is, the error compensating unit 130 may compensate for the error by moving the current vector on the d-axis to the current vectors on the -d axis and the +q axis.

Through this process, the inverter control unit 100 drives the motor 200 according to the magnetic flux angle for which the error is compensated by the error compensation unit 130 when the error between the estimated magnetic flux angle and the first magnetic flux angle becomes less than a set value. can do.

For example, when an error between the estimated magnetic flux angle and the first magnetic flux angle is within ±5 degrees, the error compensator 130 may drive the motor 200 according to the magnetic flux angle for which the error is compensated. The error determination unit 140 may determine such an error.

Thereafter, the control conversion unit 110 may output a target current according to the speed command transmitted from the sensorless driving units 300 and 310.

These sensorless (sensorless) driving units (300, 310) are a speed and position estimation unit 310 that estimates the speed and position of the motor using the output current and the target according to the speed command according to the estimated speed and position of the motor. It may include a speed controller 300 to output the current.

That is, when the initial start of the motor 200 is successful, the control conversion unit 110 may output a target current according to the speed command using the output of the speed controller 300.

Through this, it is possible to reduce a current over shoot that occurs when switching from current control for driving the motor 200 to sensorless speed control, and minimize failure of starting the motor.

2 is a flow chart showing a method of driving a motor according to an embodiment of the present invention.

According to the method of driving a motor according to an embodiment of the present invention, the step of forcibly aligning and starting the motor at a first magnetic flux angle by applying a current (S10), estimating the speed and magnetic flux angle of the motor (S20), Comparing the estimated magnetic flux angle with the first magnetic flux angle (S30), compensating for an error between the estimated magnetic flux angle and the first magnetic flux angle (S40), and the error compensated for by these steps. It may include a step (S50) of driving the motor.

Hereinafter, a method of driving a motor according to an embodiment of the present invention will be described in detail.

First, a step (S10) of forcibly aligning and starting the motor 200 at a first magnetic flux angle by applying a current may be performed.

The forced alignment and activation step (S10) may include applying a dc current and an ac current to the motor. That is, the step of forcibly aligning and starting (S10) may include a step of forcibly aligning the motor by applying a dc current to the motor (S11) and a step of forcibly starting the motor by applying an ac current to the motor (S12). have.

As an example, in the step of forcibly starting the motor by applying an ac current to the motor (S12), an ac current having the same magnitude as the dc current applied to the motor in the step of forcibly aligning the motor (S11) may be applied.

In addition, in the step of applying a dc current (S11; forcibly aligning), a dc current corresponding to an electric angle of 0 degrees may be applied to the d-axis of the dq synchronous coordinate system.

That is, in the forcibly aligning and starting step (S10), a positive current may be applied to the d-axis of the dq synchronous coordinate system, and a zero-magnitude current may be applied to the q-axis.

Thereafter, the step S20 of estimating the speed and magnetic flux angle of the motor may be performed.

In this case, the speed and magnetic flux angle of the motor may be estimated using the back electromotive force generated in the process of performing the forced alignment and starting step (S10).

That is, it is possible to estimate the speed and magnetic flux angle of the motor by sensing the output current of the inverter 210 output in the forced alignment and starting step (S10).

In this way, a step (S30) of comparing the magnetic flux angle estimated in the step (S20) of estimating the speed and the magnetic flux angle of the motor with the first magnetic flux angle that is forcibly aligned in the step (S10) of forcibly aligning and starting may be performed. .

Thereafter, a step (S40) of compensating for an error between the estimated magnetic flux angle and the first magnetic flux angle may be performed.

At this time, the error can be compensated by reducing the d-axis current negatively and increasing the q-axis current positively. That is, the error can be compensated by moving the current vector on the d-axis to the current vectors on the -d and +q axes (S41).

Through this process, it is determined whether an error between the estimated magnetic flux angle and the first magnetic flux angle is less than or equal to a set value (S42), and when the error is less than or equal to the set value, the motor may be driven according to the magnetic flux angle for which the error is compensated.

3 is a graph showing a d-axis current command value according to a motor driving apparatus and a driving method thereof according to an embodiment of the present invention, and FIG. 4 is a graph showing a motor driving apparatus according to an embodiment of the present invention and a driving method thereof. This is a graph showing the q-axis current command value.

Hereinafter, a method of driving a motor according to an embodiment of the present invention will be mainly described in detail with reference to FIGS. 1 to 4 together.

Vector control is used to perform the high-precision control required in the compressor field. Position information of the rotor of the motor 200 is required for independent torque and magnetic flux control through vector control.

It is necessary to add a position sensor such as an encoder to the system to obtain the rotor position information. However, these sensors may have problems of accuracy and reliability due to a rise in temperature due to long-term use and mechanical vibrations that occur while driving the motor.

In addition, equipment for obtaining location information requires additional cost of the system and additional hardware for operating it. Therefore, research on various sensorless control methods that do not use a sensor for measuring the position of the rotor is in progress.

Among them, the extended electromotive force (EEMF) sensorless algorithm based on the electromotive force (EMF) of the synchronous motor 200 is very simple and thus has the advantage of easy algorithm design.

According to the EEMF algorithm, it can be estimated by the current and voltage of the motor 200, and the position information of the rotor is embedded. Therefore, by estimating the EEMF, information about the position (magnetic flux angle) and speed of the rotor can be obtained. However, since the electromotive force of the motor 200 is small in the low speed and low torque regions, it is difficult to accurately estimate the position angle and speed of the rotor.

Since the permanent magnet synchronous motor 200 does not have a sensor, the initial position of the rotor cannot be known, so a forced starting method is used. In order to drive a permanent magnet synchronous motor without a sensor, the motor is forcedly aligned by applying a dc current to the d-axis at an electric angle of 0 degrees, and the actual speed of the rotor cannot be known without the position information of the rotor. It is possible to use the current controller 120 without using 300.

At the moment of switching the current controller 120 to the sensorless speed controller 300, overshoot of the rotor speed and current due to an error in the rotor position used by the current controller 120 and the rotor position used by the speed controller 300 (over shoot) may occur.

In addition, in a compressor using a gaseous refrigerant, since the actual applied load cannot be accurately known, the command current of the initial current controller 120 must be set large, and if the rotor position is not compensated after switching, the overshoot of the speed and current is large. As a result, there may be a case in which it is not possible to accurately estimate the position information of the rotor instantly. Compensating the rotor position in this way can reduce the size of the overshoot that occurs during switching.

The present invention proposes an algorithm that is robust against parameter errors while performing rotor position compensation.

Hereinafter, the present invention will be described in detail based on the control method.

First, according to the present invention, in the step (S10) of forcibly aligning and starting the motor at a first magnetic flux angle by applying a current, a dc current is applied to the d-axis at an electric angle of 0 to force the motor to be aligned. In order to forcibly align the d-axis, as shown in FIGS. 3 and 4, a positive current may be applied to the d-axis and a current of 0 to the q-axis.

Thereafter, in the step (S20) of estimating the speed and magnetic flux angle of the motor, a current is applied with the same magnitude as the dq-axis current applied during forced alignment, and in this case, an ac current rather than a dc current is applied. At this time, the frequency of the ac current uses an arbitrary frequency, and then the motor 200 initially starts around this frequency.

In the step (S20) of estimating the speed and magnetic flux angle of the motor, since only the dq-axis current is controlled and the speed is not controlled, it may be difficult to control the motor at an accurate speed. The step (S20) of estimating the speed and magnetic flux angle of the motor may be used for extracting the back electromotive force used for sensorless control while starting the motor 200 at an arbitrary speed.

Next, in the step (S30) of comparing the estimated magnetic flux angle with the first magnetic flux angle, a sensorless algorithm based on the back electromotive force generated during operation at an arbitrary speed in the step (S20) of estimating the speed and the magnetic flux angle of the motor is used. The speed and magnetic flux angle of the motor 200 are estimated by using. At this time, the speed and magnetic flux angle of the motor 200 may be estimated, but may not be used for actual speed control.

5 is a graph showing an error compensation process according to a motor driving apparatus and a driving method thereof according to an embodiment of the present invention.

In the step (S30) of comparing the estimated magnetic flux angle with the first magnetic flux angle, the magnetic flux angle estimated through the sensorless algorithm is compared with the magnetic flux angle (first magnetic flux angle) used during forced start.

Referring to FIG. 5, the first magnetic flux angle used at initial start-up is located on the d-axis, and the magnetic flux angle estimated through the sensorless algorithm is located on the -d axis and the q axis.

In this case, if the motor 200 is immediately forcibly started without compensation of the magnetic flux angle and is switched to sensorless control, a current overshoot may occur due to an error in the magnetic flux angle, thereby increasing the possibility of starting failure (see FIG. 7 ).

Accordingly, a process of reducing an error between the first magnetic flux angle used for forced start and the magnetic flux angle estimated by the sensorless algorithm may be preceded.

In the starting step (S11), a current of positive magnitude was applied to the d-axis and a current of zero magnitude was applied to the q-axis. At this time, according to the step (S40) of compensating for an error between the estimated magnetic flux angle and the first magnetic flux angle, the d-axis current is negative in order to move the magnetic flux angle at this position to the sensorless flux angle (sensorless current vector). And the q-axis current increases positively to reduce the error of the magnetic flux angle.

Thereafter, when an error between the estimated magnetic flux angle and the first magnetic flux angle falls within a set value, for example, ±5 degrees, the sensorless mode may be switched. That is, the motor can be driven according to the magnetic flux angle for which the error is compensated (S50).

If the magnetic flux angle algorithm is applied in this way, the motor can be started without current overshoot.

6 is a graph showing an applied current according to a motor driving apparatus and a driving method thereof according to an embodiment of the present invention.

This current flow coincides with the graphs shown in FIGS. 3 and 4. For example, it can be seen that the motor is forcibly driven at 1500 rpm in the initial forced driving state, and at this time, an electromotive force of 4 Nm is generated.

7 is a waveform diagram illustrating a current waveform when magnetic flux angle compensation is not performed, and FIG. 8 is a waveform diagram illustrating a current waveform according to a motor driving apparatus and a driving method thereof according to the present invention.

That is, the waveform of FIG. 7 represents a waveform that is immediately switched from forced start to sensorless control without performing the process of compensating the magnetic flux angle (S40) as described above.

In addition, the waveform of FIG. 8 represents a waveform converted from forced start to sensorless control when the process of compensating the magnetic flux angle as described above (S40) is performed.

Comparing the waveforms of FIGS. 7 and 8, when the process of compensating the magnetic flux angle (S40) is not performed, an overshoot (A) of the current occurs due to the magnetic flux angle that is suddenly changed in the process of switching to sensorless control. You can confirm that.

However, when the process of compensating the magnetic flux angle according to the present invention (S40) is performed, it can be seen that the overshoot of the current has not occurred in the process of switching to the sensorless control.

As described above, the conversion technique proposed in the present invention has its validity verified through experimental results of an actual compressor.

According to the present invention described above, it is possible to reduce a current over shoot that may occur when switching from current control of a motor to sensorless speed control, thereby minimizing a failure to start the motor. .

9 is a cross-sectional view showing a compressor to which the present invention can be applied. 9 shows a horizontal scroll type compressor.

The motor driving apparatus and method described above may be applied to a motor of a compressor, and in some cases, may exert a greater effect when applied to a motor of such a compressor. Hereinafter, such a compressor will be briefly described.

The horizontal scroll type compressor 400 includes a casing 410 having a sealed inner space, and components for compressing fluid may be installed in the casing 410. That is, in the casing 410, a motor 420, a rotation shaft 430, a fixed scroll 450 and a revolving scroll 460 that mesh with each other, and a frame 440 in which the rotation shaft 430 is installed may be included. .

The casing 410 for forming the sealed space may be formed in a horizontal cylinder shape. The casing 410 may be provided with a suction port 411 and a discharge port 412 for entering and exiting the refrigerant.

A motor 420 for generating a rotational force may be installed in the inner space of the casing 410. In addition, a rotation shaft 430 coupled to the rotor 421 of the motor 420 may be installed.

This rotation shaft 430 may be eccentrically coupled to the orbiting scroll 460. That is, the motor 420 may provide a rotational force through which the orbiting scroll 460 may orbit through the rotation shaft 430.

A frame 440 may be installed on one side of the motor 420. The frame 440 may be formed of a material having high hardness such as cast iron as a main frame. Here, the motor 420 may have the same configuration as the motor 200 described above.

The frame 440 may provide a supporting structure in which the fixed scroll 450 and the orbiting scroll 460 may be installed. That is, the fixed scroll 450 may be coupled to the frame 440 to form the compressed space 470.

At this time, the casing 410 includes a discharge chamber through which the refrigerant gas is discharged from the compression space 470, and the discharge port 412 is provided in the discharge chamber, and the refrigerant in the discharge chamber is discharged through the discharge port 412. I can.

In this discharge chamber, the oil may be separated from the refrigerant by the oil separator 414, and in this case, the oil separated on the lower side may be sucked through the oil pickup and supplied to each rotating part.

A separate inverter space 417 may be provided on the side of the suction port 411 of the casing 410, and the inverter unit 490 may be located in the inverter space 417. The inverter space 417 may be formed by an inverter casing 416 that seals the inverter unit 490 from the space in which the motor 200 is installed.

The motor 420 may include a stator 422 installed in the inner space of the casing 410 to generate rotational force, and a winding installed thereon, and a rotor 421 coupled to the stator 422.

The inverter unit 490 installed in the inverter space 417 may be electrically connected to the motor 420 to drive the motor 420. Here, the inverter unit 490 may have the same configuration as the inverter 210 described above.

Meanwhile, a bearing 431 may be installed on one side of the frame 440 to fix the rotation shaft 430 so as to be rotatable. On the other hand, in some cases, the bearing 432 is also installed on the inner end side of the casing 410 so that the rotating shaft 430 can smoothly rotate.

Between the fixed scroll 450 and the frame 440, an orbiting scroll 460 that is coupled to the fixed scroll 450 and performs orbiting motion with respect to the fixed scroll 450 may be installed.

The orbiting scroll 460 is connected to the rotation shaft 430 and is eccentrically coupled to the center of the rotation shaft 430 to implement a orbiting motion.

As described above, in the scroll type compressor 400, the compression chamber 451 may be formed between the orbiting scroll 460 and the fixed scroll 450.

Referring to part A of FIG. 9, an elastic plate 480 is positioned between the frame 440 and the fixed scroll 450, and the orbiting scroll 460 located inside the frame 440 and the fixed scroll 450 In the figure, the pressure sealing part 481 and the pressure O-ring 482 are located.

Features, structures, effects, and the like described in the above embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Further, the features, structures, effects, and the like illustrated in each embodiment may be combined or modified for other embodiments by a person having ordinary knowledge in the field to which the embodiments belong. Accordingly, contents related to such combinations and modifications should be construed as being included in the scope of the present invention.

In addition, although the embodiments have been described above, these are only examples and do not limit the present invention, and those of ordinary skill in the field to which the present invention belongs are illustrated above within the scope not departing from the essential characteristics of the present embodiment. It will be seen that various modifications and applications that are not available are possible. For example, each component specifically shown in the embodiment can be modified and implemented. And differences related to these modifications and applications should be construed as being included in the scope of the present invention defined in the appended claims.

100: inverter control unit 110: control switching unit
120: current controller 130: error compensation unit
140: error determination unit
200: motor 210: inverter
220: current sensing unit
300, 310: sensorless driving unit
300: speed controller 310: speed/position estimation unit
400: compressor

Claims (13)

In the method of controlling a motor using an inverter,
Applying a current to forcibly align and start the motor at a first magnetic flux angle;
Estimating the speed and magnetic flux angle of the motor;
Comparing the estimated magnetic flux angle with the first magnetic flux angle;
Compensating for an error between the estimated magnetic flux angle and the first magnetic flux angle; And
And driving the motor according to the magnetic flux angle for which the error is compensated. The method of claim 1, wherein the forced alignment and activation step,
And applying a dc current and an ac current to the motor. The method of claim 2, wherein the applying of the dc current comprises applying a dc current corresponding to an electric angle of 0 degrees to the d-axis of the dq synchronous coordinate system. The method of claim 1, wherein estimating the speed and magnetic flux angle of the motor comprises:
A method of driving a motor, characterized in that it is performed by using the back electromotive force generated in the forced alignment step. The method of claim 1, wherein the forced alignment and activation step,
A method of driving a motor, comprising applying a positive current to a d-axis of a dq synchronous coordinate system and applying a current of zero magnitude to the q-axis. The method of claim 1, wherein driving the motor comprises:
When an error between the estimated magnetic flux angle and the first magnetic flux angle becomes less than or equal to a set value, the motor is driven according to a magnetic flux angle for which the error is compensated. motor;
An inverter for driving the motor;
A current sensing unit sensing the output current of the inverter; And
Including an inverter control unit for controlling the inverter,
The inverter control unit,
A current controller for forcibly aligning and starting the motor at a first magnetic flux angle by applying a current;
A speed and position estimation unit that estimates the speed and magnetic flux angle of the motor;
And an error compensating unit for compensating for an error between the estimated magnetic flux angle and the first magnetic flux angle by comparing the estimated magnetic flux angle with the first magnetic flux angle. The method of claim 7, wherein the current controller,
A driving apparatus for a motor, characterized in that applying a dc current and an ac current to the motor. The method of claim 8, wherein the current controller,
A driving apparatus for a motor, characterized in that applying a dc current corresponding to an electric angle of 0 degrees to the d-axis of the dq synchronous coordinate system. The apparatus of claim 7, wherein the speed and position estimating unit estimates the speed and magnetic flux angle of the motor by using the back electromotive force generated in the process of forcibly aligning and starting the current controller. The motor driving apparatus of claim 7, wherein the current controller applies a positive current to the d-axis of the dq synchronous coordinate system and applies a current of zero magnitude to the q-axis. The method of claim 7, wherein the inverter control unit,
When an error between the estimated magnetic flux angle and the first magnetic flux angle becomes less than or equal to a set value, the error compensating unit drives the motor according to a magnetic flux angle for which the error is compensated. A compressor comprising the drive device according to any one of claims 7 to 12.

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