RU2381609C1 - Method to control static stabilised dc voltage sources operating in parallel into common load - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to electrical engineering and can be used in organising electric power generation systems or uninterrupted power supply systems with sources connected in parallel into common load. Proposed method comprises measuring instantaneous voltages at common load and source instantaneous currents, obtained magnitudes being transformed from three-phase abc-system of coordinates into two-phase dq-system of coordinates, and generating reference voltage signals for d- and q-components of total voltage. Extra voltage signals are generated in proportion to d- and q-components of total voltage. Difference voltage signals are generating by subtracting appropriate extra voltage signals from reference voltage signals. Voltage comparison signals are generated by integrating voltage signals and voltage control signals are generated by summing voltage comparison signals with those proportional to voltage difference signals. Reference signals are generated for every source operated in parallel, proportional to appropriate voltage control signals. Extra signals are generated in proportion to d- and q-components of source current, as well as difference signals, comparison signals, signal of control over summation of comparison signals. Also generated are signals proportional to difference signals and signals proportional to d- and q-components of source current. Now modulating signals in abc-coordinate system are generated.

EFFECT: expanded performances in standard and post-fault operating conditions.

1 dwg

Description

The invention relates to the field of electrical engineering and can be used in the construction of electrical energy generation systems or guaranteed power supply systems, in which to increase the output power and achieve reliable power supply, static stabilized sources of electrical energy are connected in parallel to the total load. The primary sources with varying parameters in such systems can be a synchronous generator with a variable speed of rotation of the shaft, industrial network, battery. The function of stabilizing the parameters of the output energy in such systems is assigned to static converters of electrical energy.

A known method of controlling static stabilized voltage sources of direct or alternating current, operating in parallel to the total load [A.S. USSR 1310974, Н02М 7/48. A method for controlling static frequency converters operating in parallel for a common load // E.A. Podyakov, N.I. Borodin, V.V. Ivantsov, S.A. Kharitonov, Yu.E. Semenov. - publ. 05/15/87, bull. No. 18], which consists in generating a signal for setting the output voltage of the converters, measuring the voltage at the total load and generating a negative voltage feedback signal by subtracting the signal proportional to the voltage at the total load from the voltage setting signal, measuring the output current of each converter, forming the reference signal of the load current of the converters operating in parallel by summing the signals proportional to the currents of the converters form a signal for setting the current fraction of each converter in the load current is proportional to the reference signal of the load current, with a proportionality coefficient equal to the ratio of the rated current of the given converter to the rated load current, a negative current feedback signal is generated by subtracting the signal proportional to the current of this converter from the signal for setting the current fraction of this converter and form a control signal for each converter by summing the negative feedback signals for current, voltage, and a signal for setting a fraction a.

This control method implements proportional control both by the instantaneous values of the currents and by the instantaneous value of the output voltage in each of the parallel sources, and therefore it has static errors in stabilizing the total voltage and the distribution of the load current between the sources when the load changes.

In addition, there is a known method of controlling static stabilized AC voltage sources operating in parallel to a common load [RF Patent No. 2256274, Н02Р 13/16. A method of controlling static stabilized AC voltage sources operating in parallel for a common load / N.I. Borodin, S.A.Kharitonov. - publ. 07/10/2005, bull. No. 19.], Which is a prototype of the present invention and consists in measuring the instantaneous voltage values at the total load and currents of the sources, generating the first voltage reference signal for the first stabilized total voltage parameter — the amplitude amplitude reference signal, and generating the second voltage reference signal for the second stabilized parameter of the total voltage - the reference phase signal, generate signals proportional to the active and reactive components of the power sources, the first and second standard voltage signals - the amplitudes and phases of one of the parallel sources, which is responsible for stabilizing the parameters of the total voltage, form constant and corresponding to the nominal values of the voltage parameters, form the first and second additional voltage signals in proportion to the values of the amplitude and phase of the general voltage, form the first and second difference voltage signals by subtracting the corresponding additional voltage signals from the voltage reference signals, form the first and second voltage comparison signals by integration of the first and second voltage differential signals, form the first and second voltage control signals, for each of the other parallel sources, the first and second reference signals are proportional to the active and reactive components of the power of the source, which is responsible for stabilizing the parameters of the total voltage , with a proportionality coefficient equal to the ratio of the nominal, full powers of each source and source, stub lysing voltage parameters, the first and second additional signals of the remaining sources are formed equal to the active and reactive components of their power, respectively, for each source the first and second difference signals are generated by subtracting the corresponding additional signals from the corresponding reference signals, the first and second comparison signals are generated by integrating the difference signals, in proportion to the corresponding comparison signals form the amplitude and phase of the control signal.

This control method ensures the stability of the parameters of the total voltage within the permissible limits for the load, corresponding to changes in the reference voltage signals of the source responsible for the voltage parameters, and implements the distribution of the load power components between the sources in proportion to their rated powers. However, if the formation of the output currents of the source, which is responsible for the stabilization of the voltage parameters and sets the reference signals of the power components for the remaining sources, violates the formation of voltage at the common load and the distribution of the load current components between the sources stops.

The objective of the invention is the provision of the formation of voltage at the total load and the distribution of the components of the load current between the sources while maintaining the stability of the parameters of the total voltage and the accuracy of the load distribution between the sources in the emergency mode.

This is achieved by the fact that in the known method of controlling static stabilized AC voltage sources operating in parallel for a common load, which consists in measuring the instantaneous voltage values of the total load and currents of the sources, the first and second voltage reference signals are formed with constant and corresponding nominal amplitude values and phases of the total voltage, form the first and second additional voltage signals, form the first and second differential voltage signals of the subtraction By using the corresponding additional voltage signals from the voltage reference signals, the first and second voltage comparison signals are generated by integrating the first and second voltage differential signals, the first and second voltage control signals are generated, the first and second reference signals are generated for each of the parallel sources, the first and second additional signals, the first and second difference signals by subtracting the corresponding additional signals from the reference signals, the first and second signals For comparison, by integrating the corresponding difference signals, the first and second control signals, the measured instantaneous values of the total voltage and current of each source are converted from a three-phase abc coordinate system to a two-phase dq coordinate system rotating at a constant frequency, using the first and second voltage reference signals accordingly, reference signals for the d- and q-components of the total voltage of the sources, use the signal as the first and second additional voltage signals s, proportional to the d- and q-components of the total voltage of the sources, the first and second voltage control signals are formed by summing the first and second voltage comparison signals with the signals proportional to the first and second voltage difference signals, respectively, the first and second reference signals of each source form in proportion to the first and second voltage control signals, respectively, with proportionality coefficients equal to the nominal When the current of this source is converted to the rated value of the load current, the first and second additional source signals are generated proportionally to the d- and q-components of the source current, the first and second control signals are formed by summing the corresponding comparison signals, signals proportional to the first and second difference signals, and signals proportional to the d - and q-components of the source currents, form modulating signals for each source by converting the first and second controls yayuschih signals from the two-phase dq-coordinate system in the three-phase abc-system coordinates.

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(блоки 5 и 6) соединены с вычитающими входами схем вычитания

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(блоки 7 и 8). Уменьшаемые входы схем вычитания

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(блоки 7 и 8) соединены с выходами схем формирования эталонных сигналов напряжения для d- и q-составляющих общего напряжения источников

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(блоки 9 и 10). Выходы схем вычитания

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(блоки 7 и 8) через интеграторы

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(блоки 11 и 12) и пропорциональные звенья

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(блоки 13 и 14) и через пропорциональные звенья

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(блоки 15 и 16) соединены с входами сумматоров

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(блоки 17 и 18). Выходы сумматоров соединены с входами пропорциональных звеньев I_iном/I_нном (блоки 19 и 20) в каждом из параллельно работающих источников. Выходы пропорциональных звеньев I_iном/I_нном (блоки 19 и 20) соединены с вычитаемыми входами схем вычитания

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(блоки 21 и 22), выходы которых через пропорциональные звенья

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(блоки 23 и 24) и через интеграторы

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(блоки 25 и 26) соединены с входами сумматоров

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(блоки 27 и 28). Выходы сумматоров

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(блоки 27 и 28) соединены с входами схемы обратного преобразования координат ПК^-1 (блок 29), выходы которой соединены с входами системы импульсно-фазового управления СИФУ1 (блок 30). Выходы системы импульсно-фазового управления СИФУ1 (блок 30) соединены с управляющими входами силовой схемы преобразователя СС1 (блок 31), силовой вход которой соединен с выходом первичного источника электрической энергии U_C1 (блок 32). Выходы силовой схемы преобразователя СС1 (блок 31) через силовой фильтр СФ1 (блок 33) и датчики мгновенных значений выходных токов источников ДТа, ДТв, ДТс (блоки 34, 35, 36) соединены с нагрузкой Н (блок 3). Выходы датчиков тока ДТа, ДТв, ДТс (блоки 34, 35, 36) соединены с входами схемы прямого преобразователя координат ПК (блок 37), выходы которой через пропорциональные звенья

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(блоки 38 и 39) соединены с входами сумматоров

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(блоки 27 и 28), а также через пропорциональные звенья

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(блоки 40 и 41) с вычитающими входами схем вычитания

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(блоки 21 и 22).The drawing shows one of the possible flowcharts that implements the proposed control method. This circuit implements the parallel operation of N three-phase static stabilized AC voltage sources IST ₁ , ..., HCT _N (blocks 1, 2) operating at a total load N (block 3). The load is connected to the inputs of the PC direct coordinate conversion circuit (block 4), the outputs of which are through proportional links

and

(blocks 5 and 6) are connected to the subtracting inputs of the subtraction schemes

and

(blocks 7 and 8). Reduced inputs of subtraction schemes

and

(blocks 7 and 8) are connected to the outputs of the voltage reference signal generating circuits for the d- and q-components of the total voltage of the sources

and

(blocks 9 and 10). Subtraction circuit outputs

and

(blocks 7 and 8) through integrators

and

(blocks 11 and 12) and proportional links

and

(blocks 13 and 14) and through proportional links

and

(blocks 15 and 16) are connected to the inputs of the adders

and

(blocks 17 and 18). The outputs of the adders are connected to the inputs of the proportional links I _in / I _nnom (blocks 19 and 20) in each of the parallel sources. Outputs proportional _Inom units I / I _nnom (blocks 19 and 20) are connected to the subtracting input of subtractor

and

(blocks 21 and 22), the outputs of which are through proportional links

and

(blocks 23 and 24) and through integrators

and

(blocks 25 and 26) are connected to the inputs of the adders

and

(blocks 27 and 28). Adder outputs

and

(blocks 27 and 28) are connected to the inputs of the inverse coordinate transformation circuit PC ^-1 (block 29), the outputs of which are connected to the inputs of the pulse-phase control system SIFU1 (block 30). The outputs of the pulse-phase control system SIFU1 (block 30) are connected to the control inputs of the power circuit of the converter CC1 (block 31), the power input of which is connected to the output of the primary source of electrical energy U _C1 (block 32). The outputs of the power circuit of the converter CC1 (block 31) through the power filter SF1 (block 33) and the sensors of the instantaneous values of the output currents of the sources DTa, DTv, DTs (blocks 34, 35, 36) are connected to the load H (block 3). The outputs of the current sensors DTa, DTv, DTs (blocks 34, 35, 36) are connected to the inputs of the direct coordinate converter PC (block 37), the outputs of which are through proportional links

and

(blocks 38 and 39) are connected to the inputs of the adders

and

(blocks 27 and 28), as well as through proportional links

and

(blocks 40 and 41) with subtracting inputs of subtraction schemes

and

(blocks 21 and 22).

и

(блоки 5 и 6),

и

(блоки 13 и 14),

и

(блоки 15 и 16), I_iном/I_нном (блоки 19 и 20),

и

(блоки 23 и 24),

и

(блоки 38 и 39),

и

(блоки 40 и 41), схемы вычитания

и

(блоки 7 и 8),

и

(блоки 21 и 22), сумматоры

и

(блоки 17 и 18),

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(блоки 27 и 28), интеграторы

и

(блоки 11 и 12),

и

(блоки 25 и 26) - элементарные, типовые звенья, известные из теории автоматического регулирования (см. Теория автоматического управления. Ч.1. Теория линейных систем автоматического управления. Под ред. А.А.Воронова. Учеб. пособие для вузов. - М.: Высшая школа, 1977). Схемы формирования эталонных сигналов напряжения для d- и q-составляющих общего напряжения источников

и

(блоки 9 и 10), например, параметрические стабилизаторы (см. Источники электропитания радиоэлектронной аппаратуры: Справочник / Под ред. Г.С.Найвельта. - М.: Радио и связь, 1986). Схема обратного преобразования координат ПК^-1 (блок 29) реализует известное из электромеханики и теории автоматизированного электропривода преобразование двух dq-координат системы координат, вращающейся с постоянной частотой Ω, в трехфазную, симметричную с постоянной частотой Ω abc-систему координат (см. Важнов А.И. Переходные процессы в машинах переменного тока. - Л.: Энергия, Ленингр. отд-ние, 1980) и представляет собой умножитель аналоговых сигналов (см. Тимонеев В.Н., Величко Л.М., Ткаченко В.А. Аналоговые перемножители сигналов в радиоэлектронной аппаратуре. - М.: Радио и связь. - 1982. - 112 с.). Система импульсно-фазового управления СИФУ1 (блок 30) - стандартная система импульсно-фазового управления, реализующая вертикальный принцип управления (см. B.C.Руденко, В.И.Сенько, И.М.Чиженко. Основы преобразовательной техники. - М.: Высшая школа, 1980). Силовая схема преобразователя СС1 (блок 31) может представлять собой непосредственный преобразователь частоты или последовательное включение выпрямителя и инвертора напряжения или инвертор напряжения (см. B.C.Руденко, В.И.Сенько, И.М.Чиженко. Основы преобразовательной техники. - М.: Высшая школа, 1980). Первичный источник электрической энергии U_C1 (блок 32) - промышленная сеть или синхронный генератор с переменной скоростью вращения ротора или аккумуляторная батарея. Силовой фильтр СФ1 (блок 33) может представлять собой, например, однозвенный LC-фильтр в каждой выходной фазе или С-фильтр в каждой выходной фазе. Датчики мгновенных значений выходных токов источников ДТа, ДТв, ДТс (блоки 34, 35, 36) - трансформаторы тока.The load H (block 3) may be a resistor or series or parallel connection of a resistor and inductor. Schemes of direct transformation of PC coordinates (blocks 4 and 37) implement the conversion of three-phase quantities (currents and voltages) of their three-phase abc coordinate system to the d-and q-components of the dq-coordinate system rotating with a constant frequency, known from electromechanics and the theory of an automated electric drive (see Vazhnov AI Transient processes in alternating current machines. - L .: Energy, Leningrad branch, 1980) and are multipliers of analog signals (see Timoneev VN, Velichko LM, Tkachenko V .A. Analogue signal multipliers in radio ics apparatus -. M .: Radio and communication -. 1982. - 112 s).. Proportional Links:

and

(blocks 5 and 6),

and

(blocks 13 and 14),

and

(blocks 15 and 16), I _Ir / I _nnom (blocks 19 and 20)

and

(blocks 23 and 24),

and

(blocks 38 and 39),

and

(blocks 40 and 41), subtraction schemes

and

(blocks 7 and 8),

and

(blocks 21 and 22), adders

and

(blocks 17 and 18),

and

(blocks 27 and 28), integrators

and

(blocks 11 and 12),

and

(blocks 25 and 26) - elementary, typical links, known from the theory of automatic control (see. Theory of automatic control. Part 1. The theory of linear systems of automatic control. Edited by A.A. Voronov. Textbook for universities. - M .: Higher school, 1977). Schemes for the formation of voltage reference signals for d- and q-components of the total voltage of sources

and

(blocks 9 and 10), for example, parametric stabilizers (see Sources of power supply of electronic equipment: Reference / Edited by G.S. Naivelt. - M .: Radio and communications, 1986). The inverse coordinate transformation scheme PC ^-1 (block 29) implements the transformation of two dq-coordinates of a coordinate system rotating with a constant frequency Ω into a three-phase symmetric with a constant frequency Ω abc-coordinate system known from electromechanics and the theory of an automated electric drive (see Vazhnov A .I. Transients in AC machines. - L .: Energy, Leningrad., 1980) and is a multiplier of analog signals (see Timoneev V.N., Velichko L.M., Tkachenko V.A. Analog multipliers of signals in a radioelectron equipment. - M .: Radio and communications. - 1982. - 112 p.). The pulse-phase control system SIFU1 (block 30) is a standard pulse-phase control system that implements the vertical control principle (see BCRudenko, V.I.Senko, I.M. Chizhenko. Fundamentals of converter technology. - M.: Higher school, 1980). The power circuit of the CC1 converter (block 31) can be a direct frequency converter or a series connection of a rectifier and a voltage inverter or a voltage inverter (see BCRudenko, V.I.Senko, I.M. Chizhenko. Fundamentals of converter technology. - M .: Higher School, 1980). The primary source of electrical energy U _C1 (block 32) is an industrial network or a synchronous generator with a variable rotor speed or a battery. The power filter SF1 (block 33) can be, for example, a single-link LC filter in each output phase or a C filter in each output phase. Sensors of instantaneous values of the output currents of sources DTa, DTv, DTs (blocks 34, 35, 36) are current transformers.

и

представляющие собой сигналы постоянного напряжения. Через пропорциональные звенья

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(блоки 5 и 6), согласующие уровни d- и q-составляющих общего напряжения с эталонными сигналами напряжения

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(блоки 9 и 10), d- и q-составляющие общего напряжения поступают на вычитающие входы схем вычитания

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(блоки 7 и 8), на выходах которых формируется разность эталонных сигналов напряжения и согласованных по уровням d- и q-составляющих общего напряжения. Под действием этих разностей интеграторы

и

(блоки 11 и 12) изменяют свои выходные сигналы, что приводит к изменению сигналов на выходах сумматоров

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(блоки 17 и 18), пропорциональных звеньев I_iном/I_нном (блоки 19 и 20), d- и q-составляющих управляющих сигналов на выходах сумматоров

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(блоки 27 и 28), модулирующих сигналов на выходах схемы обратного преобразования координат ПК^-1 (блок 29) и амплитуды и фазы напряжений на общей нагрузке Н (блок 3). Эти изменения сигналов будут происходить до тех пор, пока не выполнятся соотношения:The method is as follows. The three-phase voltage of the total load N is supplied to the direct coordinate conversion circuit of the PC (block 4), which is converted into d- and q-components of the total voltage

and

representing signals of constant voltage. Through proportional links

and

(blocks 5 and 6), matching the levels of the d- and q-components of the total voltage with the reference voltage signals

and

(blocks 9 and 10), the d- and q-components of the total voltage are fed to the subtracting inputs of the subtraction schemes

and

(blocks 7 and 8), at the outputs of which the difference between the reference voltage signals and the d-and q-components of the common voltage matched by the levels is formed. Under the influence of these differences, integrators

and

(blocks 11 and 12) change their output signals, which leads to a change in the signals at the outputs of the adders

and

(blocks 17 and 18), proportional links I _in / I _nn (blocks 19 and 20), d- and q-components of the control signals at the outputs of the adders

and

(blocks 27 and 28), the modulating signals at the outputs of the inverse coordinate transformation circuit PC ^-1 (block 29) and the amplitude and phase of the voltage at the total load N (block 3). These signal changes will occur until the following ratios are fulfilled:

Then the d- and q-components of the total voltage and the amplitudes and phases of the stresses associated with them through the dq-transformation of the total load are determined by the relations:

Expressions (2) show that the d- and q-components of the total voltage in the steady state do not depend on the magnitude of the load, the distribution of the load current between the sources, and with the appropriate choice of the parameter values included in expression (2), they provide nominal values of the amplitude and phase of the voltages total load.

и

(блоки 17 и 18),

и

сигналы управления напряжением, сформированные в результате выполнения соотношений (1), через пропорциональные звенья I_iном/I_нном (блоки 19 и 20) поступают в каждый из параллельно работающих источников на уменьшаемые входы схем вычитания

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(блоки 21 и 22) и являются сигналами задания для d- и q-составляющих токов источников. Измеренные датчиками ДТа, ДТв, ДТс (блоки 34, 35, 36) мгновенные значения токов источников преобразуются схемой прямого преобразования координат ПК (блок 37) в dq-систему координат. Сформированные d- и q-составляющие токов источников через пропорциональные звенья

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(блоки 40 и 41) поступают на вычитаемые входы схем вычитания

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(блоки 21 и 22). На выходах этих схем вычитания вырабатываются разностные сигналы, которые интегрируются интеграторами

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(блоки 25 и 26). Выходные сигналы этих интеграторов будут изменяться, что приведет к изменению выходных сигналов сумматоров

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(блоки 27 и 28), выходных сигналов схемы обратного преобразования координат схемой ПК^-1 (блок 29), которые являются модулирующими сигналами системы импульсно-фазового управления СИФУ1 (блок 30). В результате изменения модулирующих сигналов изменяются модулированные последовательности импульсов на выходах системы импульсно-фазового управления СИФУ1 (блок 30), включающие управляемые ключи силовой схемы источника СС1 (блок 31), которая преобразует энергию первичного источника U_C1 (блок 32) в выходную энергию с заданными параметрами, определяемыми модулирующими сигналами. Силовой фильтр СФ1 (блок 33) снижает в спектре выходного напряжения источника содержание высокочастотных составляющих, приближая напряжения и токи источника к синусоидальному виду. В результате ток источника будет изменяться до тех пор, пока в установившемся режиме выходные сигналы интеграторов

и

(блоки 25 и 26) не достигнут таких значений, при которых выполнятся соотношения:Output voltages of adders

and

(blocks 17 and 18),

and

voltage control signals generated as a result of equations (1) through proportional _Inom units I / I _nnom (blocks 19 and 20) received in each of the parallel sources is reduced at the inputs of subtraction circuits

and

(blocks 21 and 22) are the reference signals for the d- and q-component currents of the sources. Measured by the sensors DTa, DTv, DTs (blocks 34, 35, 36), the instantaneous values of the currents of the sources are converted by a direct conversion circuit of the PC coordinates (block 37) into a dq-coordinate system. Formed d- and q-components of the currents of sources through proportional links

and

(blocks 40 and 41) are fed to the subtracted inputs of the subtraction schemes

and

(blocks 21 and 22). At the outputs of these subtraction schemes, difference signals are generated that are integrated by integrators

and

(blocks 25 and 26). The output signals of these integrators will change, which will lead to a change in the output signals of the adders

and

(blocks 27 and 28), the output signals of the inverse coordinate transformation circuit by PC ^-1 (block 29), which are modulating signals of the SIPU1 pulse-phase control system (block 30). As a result of the change in the modulating signals, the modulated sequences of pulses at the outputs of the SIFU1 pulse-phase control system (block 30), including the controlled keys of the power circuit of the source CC1 (block 31), which converts the energy of the primary source U _C1 (block 32) to the output energy with the specified parameters determined by modulating signals. The power filter SF1 (block 33) reduces the content of high-frequency components in the spectrum of the output voltage of the source, bringing the voltage and currents of the source closer to a sinusoidal shape. As a result, the current of the source will change until, in the steady state, the output signals of the integrators

and

(blocks 25 and 26) the values are not reached at which the relations:

Then the d- and q-components of the currents of the sources in the steady state according to (3) are determined by the expressions:

и

), но будут всегда пропорциональны отношению номинального значения тока данного источника (I_iHОM) и номинального значения тока нагрузки (I_нном).Expressions (4) show that in the steady state, the d- and q-components of the source currents depend on the d-and q-components of the voltage control signals common to all sources (

and

), but will always be proportional to the ratio of the nominal current value of a given source (I _iHOM ) and the nominal value of the load current (I _nnom ).

и

(блоки 7 и 8). На выходах этих схем вычитания сигналы уменьшаются (увеличиваются), что передается через пропорциональные звенья

и

(блоки 15 и 16) и приводит к уменьшению (увеличению) сигналов на выходах сумматоров

и

(блоки 17 и 18) и схем вычитания

и

(блоки 21 и 22). Уменьшение (увеличение) выходных сигналов схем вычитания

и

(блоки 21 и 22) через пропорциональные звенья

и

(блоки 23 и 24) приведет к уменьшению (увеличению) выходных сигналов сумматоров

и

(блоки 27 и 28) и, соответственно, к уменьшению (увеличению) модулирующих напряжений систем импульсно-фазового управления СИФУ1 (блок 30). Это приводит к снижению изменения напряжения на общей нагрузке. Затем в результате изменения выходных сигналов интеграторов

и

(блоки 11 и 12),

и

(блоки 25 и 26) под воздействием возникших изменений выходных сигналов схем вычитания

и

(блоки 7 и 8),

и

(блоки 21 и 22) в установившемся режиме сформируются такие сигналы интеграторов, при которых выполнятся соотношения (2) и (4).When a jump-like increase (decrease) in the voltage of the primary sources of electrical energy U _C1 (block 32) increases (decreases) the voltage at the total load. This leads to an increase (decrease) in the signals at the subtracted inputs of the subtraction schemes.

and

(blocks 7 and 8). At the outputs of these subtraction schemes, the signals decrease (increase), which is transmitted through proportional links

and

(blocks 15 and 16) and leads to a decrease (increase) in the signals at the outputs of the adders

and

(blocks 17 and 18) and subtraction schemes

and

(blocks 21 and 22). Decrease (increase) in the output signals of subtraction schemes

and

(blocks 21 and 22) through proportional links

and

(blocks 23 and 24) will lead to a decrease (increase) in the output signals of the adders

and

(blocks 27 and 28) and, accordingly, to decrease (increase) the modulating voltages of the pulse-phase control systems SIFU1 (block 30). This leads to a decrease in voltage changes at the total load. Then, as a result of changes in the output signals of the integrators

and

(blocks 11 and 12),

and

(blocks 25 and 26) under the influence of the resulting changes in the output signals of the subtraction schemes

and

(blocks 7 and 8),

and

(blocks 21 and 22) in the steady state, such integrator signals are generated at which relations (2) and (4) are satisfied.

и

(блоки 38 и 39) вызывает уменьшение (увеличение) выходных сигналов сумматоров

и

(блоки 27 и 28) и после обратного преобразования координат схемой ПК^-1 (блок 29) уменьшает (увеличивает) модулирующие сигналы системы импульсно-фазового управления СИФУ1 (блок 30). Тем самым уменьшается (увеличивается) внутренняя ЭДС силовой схемы источника СС1 (блок 31), что приводит к уменьшению скачкообразного изменения напряжения на общей нагрузке.With a jump-like increase (decrease), the load resistance values decrease (increase) the load current and the currents of parallel sources. This leads to a decrease (increase) in the voltage drop at the internal resistance of the sources, and the voltage value at the total load should increase (decrease) stepwise. However, in the proposed control method, an abrupt decrease (increase) in the source currents is measured by current sensors DTa, DTv, DTs (blocks 34, 35, 36) and leads to an abrupt decrease (increase) in the d- and q-components of the currents of the sources, which through proportional links

and

(blocks 38 and 39) causes a decrease (increase) in the output signals of the adders

and

(blocks 27 and 28) and after the inverse coordinate transformation by the PC ^-1 scheme (block 29) reduces (increases) the modulating signals of the SIFU1 pulse-phase control system (block 30). Thereby, the internal EMF of the power circuit of the CC1 source is reduced (increased) (block 31), which leads to a decrease in the step-like voltage variation at the total load.

и

(блоки 9 и 10) к увеличению выходных сигналов схем вычитания

и

(блоки 7 и 8), что через пропорциональные звенья

и

(блоки 15 и 16) и в результате интегрирования блоками

и

вызовет увеличение выходных сигналов сумматоров

и

(блоки 17 и 18). Последние сигналы

и

поступают во все источники и увеличивают их эталонные сигналы для d- и q-составляющих токов источников пропорционально отношению номинального значения тока данного источника к номинальному значению тока нагрузки. Это приведет к увеличению выходных сигналов схем вычитания

и

(блоки 21 и 22), что через пропорциональные звенья

и

(блоки 23 и 24) и в результате интегрирования блоками

и

вызовет увеличение выходных сигналов сумматоров

и

(блоки 27 и 28) и модулирующих сигналов на входе системы импульсно-фазового управления СИФУ1 (блок 30). Увеличение модулирующих сигналов источников обеспечивает возрастание токов источников, и это будет происходить до тех пор, пока не выполнятся соотношения (2) и (4), но уже при новых, других значениях сигналов управления напряжением

и

. В результате вышеописанных процессов ток нагрузки перераспределится между оставшимися в работе источниками пропорционально их номинальным токам, а стабильность параметров общего напряжения будет в допустимых для нагрузки пределах, соответствующих изменениям эталонных сигналов напряжения.When the formation of the output currents of any one or several of the parallel sources stops, for example, as a result of failure of the most electrically loaded power ones at a constant load, the current of failed sources will not enter the total load. Therefore, the magnitude of the voltage at the total load will decrease. As a result, the signals at the input and output of the direct coordinate coordinate conversion circuit of the PC are reduced (block 4). This will result at constant, given voltage reference signals.

and

(blocks 9 and 10) to increase the output of subtraction schemes

and

(blocks 7 and 8) that through proportional links

and

(blocks 15 and 16) and as a result of integration by blocks

and

will cause an increase in the output signals of the adders

and

(blocks 17 and 18). Last signals

and

enter all sources and increase their reference signals for the d- and q-component currents of the sources in proportion to the ratio of the nominal current value of this source to the nominal value of the load current. This will lead to an increase in the output of the subtraction schemes.

and

(blocks 21 and 22) that through proportional links

and

(blocks 23 and 24) and as a result of integration by blocks

and

will cause an increase in the output signals of the adders

and

(blocks 27 and 28) and modulating signals at the input of the pulse-phase control system SIFU1 (block 30). An increase in the modulating signals of the sources provides an increase in the currents of the sources, and this will happen until relations (2) and (4) are satisfied, but already with new, different values of the voltage control signals

and

. As a result of the above processes, the load current is redistributed between the remaining sources in proportion to their rated currents, and the stability of the parameters of the total voltage will be within acceptable limits for the load, corresponding to changes in the reference voltage signals.

Thus, the proposed control method provides the formation of voltage at the total load and the distribution of the components of the load current between the sources while maintaining the stability of the parameters of the total voltage and the accuracy of the load distribution between the sources in normal and post-accident conditions.

Claims (1)

A method of controlling static stabilized AC voltage sources operating in parallel for a common load, which consists in measuring the instantaneous voltage values at the total load and currents of the sources, generating the first and second reference voltage signals with constant and corresponding nominal values of the amplitude and phase of the common voltage, forming the first and the second additional voltage signals, form the first and second differential voltage signals by subtracting the corresponding additional s voltage signals from the voltage reference signals, form the first and second voltage comparison signals by integrating the first and second voltage difference signals, form the first and second voltage control signals, for each of the parallel sources, generate the first and second reference signals, the first and second additional signals, the first and the second difference signals by subtracting the corresponding additional signals from the reference signals, the first and second comparison signals by integrating existing difference signals, the first and second control signals, characterized in that the measured instantaneous values of the total voltage and current of each source are converted from a three-phase abc coordinate system to a two-phase dq coordinate system rotating at a constant frequency, using the first and second voltage reference signals accordingly, the reference signals for the d- and q-components of the total voltage of the sources, the signals proportional to the first and second additional voltage signals are used respectively, with the d- and q-components of the total voltage of the sources, the first and second voltage control signals are formed by summing the first and second voltage comparison signals with signals proportional to the first and second voltage difference signals, respectively, the first and second reference signals of each source are formed proportionally to the first and the second voltage control signals with proportionality coefficients equal to the ratio of the nominal current value of this source to the rated value of the load current, the first and second additional source signals are generated proportionally to the d- and q-components of the source current, respectively, the first and second control signals are generated by summing the corresponding comparison signals, signals proportional to the first and second difference signals, and signals, proportional to the d - and q-components of the currents of the sources, form modulating signals for each source by converting the first and second control signals from d uhfaznoy dq-coordinate system in the three-phase abc-system of coordinates.