RU2502172C1 - Device for balanced stabilised power supply to high-duty consumers - Google Patents

Abstract

FIELD: electricity.SUBSTANCE: electric power consumers are in-series connected to a direct current source. Individual general-purpose reversible controlled PWM-converter is parallel connected to each consumer and implements controlled current take-off or current addition to the required level of the chosen power consumption stabilisation parameter. Individual feedback sensors with a control assembly are included together with reversible PWM-converter to an automatic control system of the chosen power consumption stabilisation parameter. An individual general-purpose digital conversion board (IGDCB) is connected to a computer digital exchange line. The board is built into the reversible converter assembly, and in addition to the digital conversion function of measured signals, it is intended to generate a general list of unit control functions. All IGDCB boards are parallel connected through a communication line to the computer that establishes and supports the chosen system mode by subsequent interrogation of sensors of units, storage battery and consumers.EFFECT: obtaining maximum efficiency at observance of the requirement of accurate control of the chosen parameter of electric power in an automatic control mode of high-duty units, thus providing up-to-date quality of power supplied to each consumer.1 dwg

Description

Technical field

The invention relates to the field of energy, and is intended for power supply of direct current consumers of high power, and allows high-precision with maximum efficiency (at the level of modern converters) to carry out precision controlled power supply of direct current consumers.

This development can be implemented in complex technological complexes of high power associated with the simultaneous operation of a large number of powerful DC and AC motors, amplitude-frequency controllers for various purposes, heaters, electric arc evaporators, high-frequency induction furnaces and heaters, ventilation and blowing devices, control units temperatures of various objects, devices for the formation of magnetic and electric fields operating in such energy-intensive industries, etc. duction, such as metallurgy, power generation, metal rolling production, accelerating technics and others.

Currently, power supply to industrial enterprises is carried out on alternating three-phase current. Often, in order to achieve uninterrupted power supply (PSU), a diesel installation and a rechargeable battery are included in the power system, which also provides operational power to DC consumers, and the capacities of consumers, converters, motor generators, and mechanical rectifiers can vary by tens of times. For example, rectifiers - according to the power consumed by the load - are divided into low-power - units of kW, medium power - tens of kW and high power - more than 100 kW [5]. With regard to uninterruptible power supplies (UPS), it is customary to classify devices from 250 to 3000 W as low-power, medium power from 3 to 30 kW, high power from 10 to several hundred kW. In the present invention we are talking about the precision power supply of dozens of consumers with a total power above the upper reduced range using one adjustable rectifier.

State of the art

Energy complexes of comparable, often lower power, are known with similar purpose and parameter requirements.

In the analogs below, a storage battery (AB) is used as the main element of energy exchange or an energy source, although other drives can be used with varying degrees of efficiency - superconducting, cryogenic, mechanical, warm inductive, exotic, capacitive, etc. The last of of the listed methods of energy storage - a capacitor bank - in terms of power (megawatt level) and economic parameters is as close as possible to the problems solved in the proposed application.

So, for example, the invention [1] contains one source of direct current, which supplies several consumers with different currents. In this case, the difference in the currents of individual consumers occurs when connecting a different number of batteries, or sections within a separate battery. One - the main source, it is also a charging unit (rectifier) - serves only to pre-charge the battery. The result is achieved by switching a different number of batteries and sections in relation to each consumer individually. Switching is carried out by mechanical switches - by commands from the control device. The number of such source assemblies corresponds to the number of consumers. In the invention [1], the loads with respect to the power source are connected in parallel, although the main sources are the same, but the number of battery assemblies corresponds to the number of loads; Moreover, each battery assembly, in fact, is, as in a conventional system, an autonomous power source for its consumer.

The disadvantages of the invention are:

- there is no possibility of smooth regulation of the power supplied to the consumer, regulation is carried out discretely with a step of a section, with a step of an AB element;

- the “control device” operating in manual mode does not provide a variety of requirements for modern converters, related to the accuracy of regulation of the selected power parameter, maintenance of the optimal operating mode, current reversal at each consumer, etc.

- an additional factor of instability caused by the voltage drop at the consumer, due to the voltage drop on the battery cells during the discharge, which can reach ten percent;

- a stationary cable network of connections with consumers consists of cables with excessive cross-section (each cable can, in a certain combination of switches, be in maximum current mode, while others are de-energized), in such a device the cost of a cable network is maximum.

In the device [2], an inverter is supposed to be included in the power supply system, which is powered by a DC battery and connected by its output in parallel with the main power supply of the consumer, with a measuring device included in the consumer’s connection circuit and a control device. In the case of a predicted excess of power consumption, the operator can initiate a recharge of electricity from a pre-charged battery through an inverter. A large number of the system operating modes claimed by the invention, various properties of consumers and energy sources are considered, the drawback of the device is that the operator manually controls and controls the parameters.

The invention [3] presents a number of methods for placing capacitors with respect to one or more energy sources, consumers and consumer groups of medium and high power and with different quality and uninterrupted power. The circuits are based on a capacitor (or group) having a relatively high energy storage capacity, connected to the specified source and to the consumer (s) through the power distribution system, the transmission path of a part of the electric power from the specified source to the specified capacitor for energy storage during its low consumption , a device for converting AC electricity from a specified source into DC electricity for storage in a capacitor, a conversion inverter and transmitting the amount of energy stored by the capacitor in the power distribution system during a period of high energy consumption, instrumentation to ensure that the capacitor is automatically connected to the power source and to the power distribution system. At the same time, the storage capacitor and energy exchange equipment can:

a) be located at or near a source of electricity,

b) be performed on a mobile vehicle with the ability to charge in one place and discharge here or in other places,

c) connect at the time of drawdowns of the main supply network,

d) connect at the time the cost of energy increases.

The disadvantage of using a capacitor energy storage device, unlike AB, should be considered a relatively sharp voltage drop across the capacitors during long-term power take-off, which reduces the stability of the converters and complicates their design. On the battery, the voltage changes in a much smaller range for the entire time the power returns (critical discharge mode is excluded). In addition, drives on capacitors, ionistors, having an energy intensity of tens of megajoules, are voluminous, technically complex, expensive structures.

Closest to the proposed invention is a device [4], which includes an adjustable constant current source, a battery, sensors controlling the parameters of electricity, electricity consumers equipped with pulse-width modulators (PWM) converters, each of which includes a high-frequency transformer, PWM controller , high-speed protection node, power switches and drivers. The inventors [4] propose increasing efficiency and reducing the overall dimensions of the system by creating several stabilized, galvanically isolated DC power channels for consumers, without double conversion. In each channel - according to the number of consumers - powered from one common rectifier, there is a PWM converter (inverter), a control device, a pulse switch, a high-frequency power transformer and a rectifier. The transformer is wound with two primary windings, through which high-frequency power can be transmitted independently and then rectified to the consumer of this channel. At the same time, the charging buffer device (ZBU) of the battery, also designed according to the PWM converter principle, is low-power, providing battery charge only when the system consumers are disconnected. In normal mode, the ACU provides only a recharge of batteries, and consumers are powered by one common rectifier through an individual converter. The authors of [4] ruled out a double conversion, further increasing the efficiency.

The power system [4] is arranged on the principle of parallel power supply to consumers from a common source on an individual cable route for each consumer, and the power of the converter corresponds to the power of the consumer. The disadvantage [4] is the limitation of consumer power at the average level, that is, today it is limited to tens of kilowatts, and the price for each kW during PWM conversion is about 2-3 times higher compared to thyristor of the same power. In addition, [4] does not provide for the possibility of adjusting the selected energy consumption parameter.

Disclosure of invention

The invention solves the problem of obtaining the maximum efficiency of the device while observing the precise regulation of the transmission of electricity to consumers in the automatic control mode of large power units, ensuring modern quality of energy consumption.

The technical problem is solved by the fact that the proposed device includes an adjustable DC source, battery, sensors control the parameters of electricity, electricity consumers. Electricity consumers are equipped with pulse-width modulators (PWM) converters, each of which includes a high-frequency transformer, a PWM controller, a high-speed protection unit, power switches and drivers. Electricity consumers are connected to a direct current source in series, and in parallel with each consumer, an individual universal reversible controlled PWM converter is connected with the ability to stabilize the selected electricity parameter of each individual consumer. The PWM converter additionally includes individual feedback sensors, a controller assembly, an individual digital conversion board connected to the computer’s digital communication line.

Distinctive features of the invention are:

- electricity consumers are connected in series with a direct current source, which allows passing an average current from a common unstabilized rectifier (for example, thyristor) of high power common to all consumers;

- in parallel with each consumer, an individual universal reversible controllable PWM converter is connected, which provides controlled current sampling, or current addition to the required level of the selected parameter for stabilizing energy consumption;

- individual feedback sensors with the regulator node are included, together with a reversible PWM converter, in the automatic control system of the selected energy stabilization parameter;

- an individual universal digital conversion board (ICCP) is connected to the computer’s digital exchange line, which is built into the reverse converter assembly and, in addition to the function of digital conversion of the measured signals, is designed to develop a general list of functions - turning on, turning off, responses, setting reference levels of the unit control signals. All ICCP boards are connected in parallel through a communication line with a computer that installs and supports the selected system mode, sequentially polling the sensors of the units, system consumers, and the battery.

The device diagram is presented in figure 1, where

1-1, 1-2, 1-n - consumers of electricity,

2 - channel series-connected consumers,

3 - common cable,

4 - adjustable, unstable source of high power,

5 - reversible converters,

6 - battery

7 - electric power sensor,

8 - individual digital exchange cards,

9 - digital communication line,

10 - computer

11 - regulator stabilization parameter

12 - high-frequency transformer.

Consumers 1-1, 1-2, ... 1-n DC energy are connected in series and form a channel - 2 consumers connected in series. Channel one for all consumers with a common cable - 3 is connected to an adjustable, unstable source of high power - 4. In parallel with each consumer of the main source current, reverse converters are included - 5-1, 5-2, ... 5-n (according to the number of consumers), capable of carry out a reverse exchange of energy with the battery - 6. Electricity sensor - 7-1 is connected via an individual digital exchange board - 8 via a digital communication line - 9 to a computer - 10. The reversing converter includes a parameter stabilization regulator 11, A driver, power switches, high frequency transformer - 12.

The device operates as follows.

Instead of the traditional way of supplying direct current consumers with regulated power, which most often consists in independent and separate supply of each individual consumer with an individual regulated source and communication cables, consumers 1-1, 1-2, ..., 1-n of direct current energy are connected in series and form a channel - 2 consumers connected in series. One channel for all consumers with a common cable - 3 is connected to an adjustable, unstable source of high power - 4 (low requirements for the source also determine its low cost).

In parallel with each consumer of the main source current, reversible converters are included - 5-1, 5-2, ... 5-n (by the number of consumers), capable of reversing energy exchange with the battery - 6. Reversing converter automatically, using the signal from the electric power sensor - 7-1, connected through an individual digital exchange board - 8 via a digital communication line - 9 with a computer - 10, stabilizes the voltage of the battery in parallel with the stabilization of the selected parameter of the consumer’s electricity. There are two possible modes of operation of the reversing converter - power take-off mode, or power addition mode from (to) the consumer. The reversing converter includes a parameter stabilization regulator 11, which generates voltage controlling the pulse-width modulator, drivers, power switches, and a high-frequency transformer - 12. Stabilization of the selected consumer parameter is carried out, as in the case of AB, by a computer through feedback along a circuit that includes sensors energy, individual digital exchange cards, digital communication lines, controller assembly, pulse-width modulator, drivers, switches, high-frequency transformer, mutators.

In the submitted application, the main power for the consumer is generated by a common source of high power, and stability is achieved by a precision reversible converter (PWM) with power plus or minus with respect to the common source. In this case, the control range is equal to twice the power of the reversing converter. A new quality of the system arises, associated with the ability to control a large power system, when the main part of the consumer’s power comes from the main - a single source, and the power providing the range and accuracy of control comes from a reversing converter. At the same time, the only battery performs the original function of energy exchange - a damper - an energy storage device with subsequent recovery of its surplus with the help of converters either to the network or to consumers with insufficient energy, which allows to achieve maximum energy savings, improve system control parameters. A computer control device automatically implements additional goals related to the accumulation of energy taken away and excessive for loads. The device uses only modern energy converters, which leads to maximum efficiency.

The claimed invention provides for the expansion of functionality and new quality of a computer-based device. There was an opportunity to supply consumers with much greater power with stabilization of any selected parameter of energy consumption (current, voltage, power, temperature, etc.).

Literature

1. Shvedyuk I.P., Shumakov N.A. RF patent No. 2028706 "Multichannel power system" - from 09/02/1995

2. Schwaigert Harald (AT), APPEL Wilhelm (AT) RF patent No. 2340992 "Device for covering peak load" - from 10.02.2005

3. PROVENZANA John M. (US) and others. Patent of the Russian Federation No. 2298867 "The system of balancing power load and batch energy storage" - from 10.10.2001

4. Nikitin Igor Evgenievich, Bushuev Vladimir Mikhailovich RF patent №2221320 “Uninterruptible power supply device multi-channel stabilizing” - from 18.12.2001

5. Material from the Internet: http://electricalschool.info/

Claims (1)

Balanced stabilized power supply device for high-power consumers, including an adjustable DC source, battery, power control sensors, power consumers equipped with pulse-width modulators (PWM) converters, each of which includes a high-frequency transformer, PWM controller, high-speed protection unit , power switches and drivers, characterized in that the consumers of electricity are connected to a DC source Consequently, in parallel with each consumer, an individual universal reversible controlled PWM converter is connected with the possibility of stabilizing the selected electric power parameter of each individual consumer, additionally including individual feedback sensors, a regulator assembly, an individual digital conversion board connected to the computer’s digital exchange line.