RU2444833C1 - Vector method for control of three-phase static converter with asymmetric load - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: in the vector method of control a three-phase output value is converted into a rotary dq-system of coordinates, zero reference values of harmonic components are generated for d- and q-components of the output value, for d- component of the output value the reference signal is generated accordingly to the rated value of the output value, the reference signal of q-component of the output value is generated as zero, the above specified signals of comparison of d- and q-components of the output value are generated by integration of differences of appropriate reference signals and signals proportionate to d- and q-components of the output value, difference signals are generated by distraction of signals proportional to d- and q-components of the output value from the appropriate reference signals of harmonic components, in difference signals for d- and q-components of the output value the harmonic components are extracted with high amplification ratio, and the specified control signals for d- and q-components of the output value are generated by summation of the appropriate comparison signals and extracted harmonic components for d- and q-components of the output value.

EFFECT: higher quality of generated power due to exclusion of reverse sequence from a three-phase signal in case of a non-symmetrical load and due to increased accuracy of direct sequence stabilisation.

3 dwg

Description

The invention relates to the field of electrical engineering and can be used to control a three-phase static converter with an asymmetric load, which is part of an autonomous system for generating electrical energy, uninterruptible power supply systems, power supply systems, etc.

There is a vector method for controlling a three-phase static converter [RF Patent No. 2207698 H02M 7/72, H02P 9/42, 21/00. A vector way to control a quadrant voltage inverter as part of an alternating current electric energy generation system / S.A. Kharitonov, A.A. Stennikov. - publ. 06/27/2003. - Bulletin No. 18], which measures the voltage and power of the synchronous generator, the network voltage and the voltage at the filter capacitor of the DC link, converts the voltage of the synchronous generator and the network voltage from a three-phase abc coordinate system to a two-phase α, β coordinate system , for a two-phase coordinate system, a reference signal is generated for the zero phase angle of the output current for each output phase of the converter in phase with the voltage of the corresponding network phase and a reference signal for the static output power converter, and the power reference signal is 90 ° ahead of the reference signal at the zero phase angle of the output current, the α and β components of the reference signal at the zero phase angle of the output current are formed proportionally to the α and β components of the converted phase network voltages, the α component the signal of the task for the output power of the static converter is formed as the product of the β-component of the mains voltage and the signal generated as the difference of the signal proportional to the power supplied by the generator and the signal is determined much like the difference between the voltage reference signal at the filter capacitor and the voltage feedback signal at the filter capacitor, the β-component of the reference signal to the output power of the static converter is formed as the product of the α-component of the mains voltage taken with the opposite sign and the signal generated as the signal difference proportional to the power supplied by the generator, and a signal defined as the difference between the voltage reference signal at the filter capacitor and the voltage feedback signal at filter capacitor, form the α- and β-components of the control signal by summing respectively the α- or β-components of the reference signal to the zero phase angle of the output current and the reference signal to the output power of the static converter, form a modulating signal with an inverter by converting the α- and β-components of the control signal from a two-phase α, β-coordinate system to a three-phase abc-coordinate system.

This method is implemented with a symmetrical network voltage system and takes into account only the direct sequence of the three-phase network voltage system. The method does not realize the reduction of the reverse and zero sequences with an asymmetric voltage system. The reverse voltage sequence creates a braking torque when powered by an asymmetric voltage system of AC electrical machines.

There is a vector method for controlling a converter [RF Patent No. 2144729 H02M 5/27, G05F 1/40. A vector way to control the converter / S.A. Kharitonov, V.V. Mashinsky - publ. 01/20/2000, - Bulletin No. 2], which is the prototype of the present invention and consists in measuring the instantaneous values of the three-phase output value of the inverter, voltage or current, isolating the zero sequence of the three-phase output voltage of the inverter, converting the values from the three-phase abc coordinate system into a two-phase α, β-coordinate system, for a two-phase coordinate system and a zero sequence, reference signals are generated, and for a zero sequence, a reference signal is formed zero, a signal is generated comparison channels by subtracting the α, β components and the zero sequence voltage of the three-phase output voltage of the inverter from the corresponding reference signals, proportionally to the comparison results form the corresponding control signals, which convert from the two-phase system of α, β-coordinates into a three-phase abc-coordinate system, form a three-phase modulating signal by summing the converted α- and β-components of the control signals and the zero-sequence control signal.

When using a static converter to convert the energy of the primary source into the output energy with the specified parameters as a result of switching the converter valves, the output quantity, voltage or current will contain a wide range of harmonic components. Therefore, when converted to a two-phase coordinate system, the converted signals will contain, in addition to the main harmonic component, a wide range of harmonic components.

The quality of the generated electricity with this control method will be low, since this method does not regulate the reverse sequence of the three-phase system of output voltages that occurs with an asymmetric load. In addition, the conversion used to the α, β coordinate system, where the components are sinusoidal signals, does not allow for high accuracy of stabilization or regulation of direct sequence voltage due to the finiteness of the gain of the corresponding static control loops for α and β components.

The objective of the invention is to improve the quality of the generated electricity with an asymmetric load and increase the accuracy of stabilization of the direct sequence of the output quantity.

The problem is achieved in that in the known vector method for controlling a three-phase converter, which consists in measuring the instantaneous values of a three-phase output value of the converter, voltage or current, converting the measured value from a three-phase abc coordinate system to a two-phase coordinate system, for a two-phase coordinate system reference signals, form comparison signals, form control signals that convert from a two-phase coordinate system to a three-phase abc coordinate system nat, proportionally to the converted signals, they form a three-phase modulating signal of the converter, a three-phase output quantity is converted into a dq coordinate system rotating at a constant frequency of the main harmonic component of the output quantity Ω, zero reference signals of harmonic components for the d- and q-components of the output quantity are generated, for d- component of the output quantity, the reference signal is formed according to the nominal value of the output quantity, the reference signal is the q-component of the output quantity form zero, these comparison signals of the d- and q-components of the output quantity are formed by integrating the differences of the corresponding reference signals and signals proportional to the d- and q-components of the output quantity, the difference signals are formed by subtracting signals proportional to the d- and q-components of the output quantity from the corresponding reference signals of the harmonic components, in the difference signals for the d and q components of the output quantity, harmonic components with a large gain are extracted, and These control signals for the d- and q-components of the output quantity are formed by summing the corresponding comparison signals and the selected harmonic components for the d- and q-components of the output quantity.

(блок 7) и

(блок 8) соединены с соответствующими вычитаемыми входами схем вычитания d- и q-составляющих (блоки 9 и 10). Вторые уменьшаемые входы указанных схем вычитания последовательностей соединены с выходами схем формирования эталонных сигналов d- и q-составляющих напряжения

и

(блоки 11 и 12). Выходы соответствующих схем вычитания соединены с входами интеграторов регуляторов d- и q-составляющих И^d и И^q(блоки 13 и 14). Одновременно выходы пропорциональных звеньев

(блок 7) и

(блок 8) соединены с вычитающими входами схем вычитания (блоки 13 и 14). Уменьшаемые входы схем вычитания (блоки 13 и 14) соединены с соответствующими выходами схем формирования эталонных сигналов гармонических составляющих

и

(блоки 15 и 16). Выходы схем вычитания (блоки 13 и 14) соединены с входами схем выделения гармонических составляющих W_pi (блоки 21, …, 26) для d- и q-составляющих. Выходы схем выделения гармонических составляющих W_pi (блоки 21, …, 26) поступают на сумматоры d-составляющей (блок 27) и q-составляющей (блок 28), выходы которых соединены с входами соответствующих сумматоров (блоки 19 и 20). Вторые входы сумматоров соединены с выходами соответствующих интеграторов (блоки 17 и 18).Figure 1 shows one of the possible structural schemes that implements the proposed method for stabilizing the output voltage of the Converter. Figure 2 and figure 3 shows the simulation results of the proposed vector control method. The circuit (Fig. 1) contains a SIFU pulse-phase control system (block 1), the outputs of which are connected to the power circuit of the inverter static frequency converter (block 2). The power circuit of the converter is also connected to the primary source of electricity with unstable parameters Uc (block 3). The output of the power circuit of the inverter static frequency converter (block 2) through the output filter Ф (block 4) is connected to the unbalanced load N (block 5). At the same time, the converter output is directly connected to the inputs of the PC coordinate converter (block 6). Outputs of PC coordinate converters via proportional links

(block 7) and

(block 8) are connected to the corresponding deductible inputs of the subtraction schemes of d- and q-components (blocks 9 and 10). The second diminished inputs of these sequence subtraction schemes are connected to the outputs of the d-and q-component voltage generating circuits

and

(blocks 11 and 12). The outputs of the corresponding subtraction schemes are connected to the inputs of the regulator integrators of the d- and q-components And ^d and And ^q (blocks 13 and 14). At the same time, proportional link outputs

(block 7) and

(block 8) are connected to the subtracting inputs of the subtraction schemes (blocks 13 and 14). The reducible inputs of the subtraction schemes (blocks 13 and 14) are connected to the corresponding outputs of the schemes for generating the reference signals of harmonic components

and

(blocks 15 and 16). The outputs of the subtraction circuits (blocks 13 and 14) are connected to the inputs of the harmonic component extraction circuits W _pi (blocks 21, ..., 26) for the d and q components. The outputs of the harmonic component extraction circuits W _pi (blocks 21, ..., 26) are fed to the adders of the d-component (block 27) and q-component (block 28), the outputs of which are connected to the inputs of the corresponding adders (blocks 19 and 20). The second inputs of the adders are connected to the outputs of the respective integrators (blocks 17 and 18).

The outputs of the adders (blocks 19 and 20) of the d- and q-components are connected to the inputs of the circuits of the inverse coordinate transformation PC ^-1 (block 29). The outputs of the circuits of the inverse coordinate transformation PC ^{-1 are} connected to the inputs of the pulse-phase control system of SIFU (block 1).

The SIFU pulse-phase control system (block 1) is a standard control system that implements the vertical control principle (see BCRudenko, V.I.Senko, I.M. Chizhenko. Fundamentals of converting technology. - M.: Higher school, 1980). The power circuit of a static frequency inverter (block 2) is an autonomous voltage inverter using fully controllable switches (see BC Rudenko, V. I. Senko, I. M. Chizhenko. Fundamentals of converter technology. - M.: Higher school, 1980) ; the primary source of electricity with unstable parameters Uc (block 3) is a constant voltage source, for example, a rectifier according to any known scheme (see BCRudenko, V.I.Senko, I.M. Chizhenko. Fundamentals of converting technology. - M .: Higher. school, 1980) or battery; output filter F (block 4) is a low-pass filter that suppresses the high-frequency components of the spectrum of the output value, for example, a single-link LC filter; unbalanced load N (block 5) - parallel or series connection of the resistor and inductor.

The PC coordinate converter (block 6) implements the conversion of the Signal Park from the abc coordinate system to the dq coordinate system rotating at a constant frequency Ω (see Vazhnov A.I. Transient processes in AC machines. - L.: Energy, Leningrad. -nie, 1980) and can be multipliers of analog signals (see Timoneev V.N., Velichko L.M., Tkachenko V.A. Analog signal multipliers in electronic equipment. - M.: Radio and communications. - 1982. - 112 p.). Proportional links (blocks 7, 8), subtraction schemes (blocks 9, 10 13 and 14), integrators (blocks 17 and 18) and adders (blocks 19, 20, 27 and 28) are typical elementary links known from the theory of automatic regulation (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 reference signals (blocks 11, 12, 15, and 16) are parametric voltage stabilizers (see Sources of power supply of electronic equipment: Handbook / Edited by G.S. Naivelt. - M .: Radio and communications, 1986). Schemes of the inverse coordinate transformation PC ^-1 (block 29) implements the conversion from a rotating two-phase dq-coordinate system to a three-phase abc-coordinate system (see Vazhnov A.I. Transient processes in AC machines. - L .: Energy, Leningrad. Department -nie, 1980) and can be multipliers of analog signals (see Timoneev V.N., Velichko L.M., Tkachenko V.A. Analog signal multipliers in electronic equipment. - M.: Radio and communications. - 1982. - 112 p.). The allocation of harmonic components W _pi (blocks 21, ..., 26) can be resonant links, for example,

or

,

,

implemented in analog form (see. Theory of automatic control. Part 1. Theory of linear systems of automatic control. Edited by A.A. Voronov. Textbook for universities. - M .: Higher school, 1977), and to exclude temperature dependence link parameters in digital form (see Sergienko A.B.Digital signal processing. - St. Petersburg: Peter. - 2006. - 751 p.).

и

(блоки 11 и 12), пропорциональными звеньями

и

(блоки 7 и 8). На выходах схем вычитания (блоки 9 и 10) формируется разность соответствующих эталонных сигналов и d- и q-составляющих выходного напряжения. При наличии несимметричной нагрузки прямая последовательность при преобразовании в dq-систему координат образует сигналы постоянного напряжения в d- и q-составляющих выходного напряжения, а обратная последовательность образует гармонические составляющие в преобразованных сигналах, максимальная по амплитуде из которых представляет собой вторую гармоническую составляющую по отношению к выходной частоте. Эти разности преобразуются интеграторами d-и q-составляющих И^d и И^g (блоки 17 и 18), и на выходах соответствующих интеграторов формируются сигналы сравнения d- и q-составляющих (блоки 17 и 18). Одновременно сигналы, пропорциональные d- и q-составляющим напряжения нагрузки, поступают на вычитаемые входы соответствующих схем вычитания (блоки 13 и 14). На уменьшаемые входы схем вычитания (блоки 13 и 14) поступают нулевые эталонные сигналы гармонических составляющих

и

(блоки 15 и 16). На выходах схем вычитания формируются разностные сигналы для d- и q-составляющих. Схемами выделения гармонических составляющих W_pi (блоки 21, …, 26) из разностных сигналов выделяется конечное число гармонических составляющих, которые суммируются (блоки 27 и 28) для d- и q-составляющих и с соответствующими сигналами сравнения (блоки 19 и 20).The method is as follows. An asymmetric three-phase load voltage N (block 5) is supplied to the output of the coordinate converter PC (block 6), at the output of which d- and q-components of the output voltage are formed, which are consistent in magnitude with the reference signals

and

(blocks 11 and 12), proportional links

and

(blocks 7 and 8). At the outputs of the subtraction schemes (blocks 9 and 10), a difference is formed between the corresponding reference signals and the d- and q-components of the output voltage. When there is an asymmetric load, the direct sequence when converted into a dq-coordinate system forms constant voltage signals in the d- and q-components of the output voltage, and the reverse sequence forms harmonic components in the converted signals, the maximum amplitude of which is the second harmonic component with respect to output frequency. These differences are converted by the integrators of the d-and q-components And ^d and And ^g (blocks 17 and 18), and at the outputs of the corresponding integrators the signals of comparison of the d- and q-components (blocks 17 and 18) are generated. At the same time, signals proportional to the d- and q-components of the load voltage are fed to the deductible inputs of the corresponding subtraction circuits (blocks 13 and 14). At the reduced inputs of the subtraction schemes (blocks 13 and 14), zero reference signals of harmonic components

and

(blocks 15 and 16). At the outputs of the subtraction schemes, differential signals are generated for the d- and q-components. The harmonic components W _pi (blocks 21, ..., 26) are extracted from the difference signals from a finite number of harmonic components, which are summed (blocks 27 and 28) for the d and q components and with the corresponding comparison signals (blocks 19 and 20).

The signals generated at the outputs of the adders (blocks 19 and 20) are converted by the inverse coordinate transformation circuit PC ^-1 (block 29) from the dq coordinate system to a three-phase abc coordinate system. At the outputs of the inverse coordinate transformation circuit PC ^-1 (block 29), modulating signals for the SIFU pulse-phase control system are formed in proportion to the converted signals (block 1). Based on these modulating signals, the SIFU pulse-phase control system (block 1) generates control pulses that are supplied to the controlled keys of the power circuit of the inverter static frequency converter (block 2). The keys of the power circuit are switched in accordance with the change in the modulating signals, and thereby the conversion of the electrical energy of the primary source of electricity with unstable parameters Uc (block 3) into a three-phase voltage of a given frequency and magnitude is realized. The output filter F (block 4) reduces its high-frequency components in the spectrum of the output voltage, approximating the shape of the output voltage to a sinusoidal one.

The elimination of harmonic components in the d- and q-components of the load voltage is achieved due to the fact that in the proposed control method, in contrast to the prototype method, for each excluded harmonic component its own and very large gain is used, and each component is extracted with a phase a shift close to zero. The exclusion of harmonic components in the d- and q-components of the load voltage indicates that there is no reverse sequence in the output voltage, due to which the quality of the generated energy increases.

The proposed conversion of a three-phase voltage to a rotating dq-coordinate system leads to the formation of a direct sequence of the load voltage in the form of constant voltage signals in the d- and q-components of the load voltage. Therefore, the proposed formation of comparison signals by integrating the differences of the corresponding reference signals and signals proportional to the d- and q-components of the output quantity allows us to implement astatic control of the parameters of the direct sequence of the output voltage and to eliminate static errors when stabilizing the direct sequence of the load voltage.

According to the block diagram in figure 1, the image of the signals at the outputs of the adders (blocks 19 and 20) can be written in the form:

- изображение формируемого сигнала на выходе сумматоров;Where

- image of the generated signal at the output of the adders;

- изображение эталонных сигналов d- и q-составляющих выходного напряжения;

- An image of the reference signals of the d- and q-components of the output voltage;

- изображение эталонных сигналов для выделенных гармонических составляющих в d- и q-составляющих выходного напряжения;

- an image of reference signals for the selected harmonic components in the d- and q-components of the output voltage;

- изображение d- и q-составляющих выходного напряжения;

- image of the d- and q-components of the output voltage;

,

- коэффициенты пропорциональности;

,

- proportionality coefficients;

W ^{d (q)} (S) is the transfer function of the integrators of the d- and q-components of the output voltage;

W _pi (S) - image of the transfer function of the allocation circuit of the i-th harmonic component.

At the output of the inverse coordinate transformation circuit (block 29) in the time domain, modulating signals for SIFU are formed:

where L ^-1 {...} is the inverse Laplace transform operation.

We represent the sine and cosine functions in terms of exponential functions according to Euler's formulas:

We use the theorem of displacement of the argument S in the image of the function during the Laplace transform by multiplying this function in the time domain by an exponential function and transforming the expression (2) into the region of the complex variable S taking into account relations (1) and (3). As a result, we obtain an image of phase modulating signals in the region of the complex variable S: U _ma (S), U _mb (S), U _ms (S), which are the algebraic sum of expressions (1) with the shifted complex variable S by -jΩ or by + jΩ depending on the sign of the argument of the exponential functions of expressions (3).

According to the block diagram shown in figure 1, the image phase load voltage U _on (S), U _nb (S), U _nc (S) can be written in the form:

where K _IF - gain of the power circuit of the Converter taking into account SIFU;

W _нi (S) - transfer function of the linear part of the power circuit of the converter, taking into account the nature and asymmetry of the load.

These phase load stresses are transformed from a three-phase abc coordinate system to a two-phase, rotating dq coordinate system according to known relations:

If we again represent the sine and cosine functions through exponential functions according to Euler formulas (3) and use the bias theorem of the complex variable in the Laplace transform, then the images of the d- and q-components of the load voltage are written in the form:

We substitute the phase voltage images (4) and the modulating voltage images into expressions (6) according to (2) and (1). After rather cumbersome but not complicated algebraic transformations, we express from (6) the image of the d- and q-components of the load voltage in a closed-loop control system, determined by the parameters of the blocks shown in Fig. 1.

Where

Re _j [...]; Im _j [...] are the real and imaginary parts of a complex number.

Using expressions (7) and (8), we determine the value of the k-th harmonic component ω _k in the d- and q-components of the load voltage for the proposed control method. To do this, we present in the sums of the numerator and denominator of expressions (7) and (8) the transfer functions of the allocation schemes for the k-th harmonic component ω _{k in the} form:

The image of the constant reference signals can be represented as:

;

;

;

- постоянные сигналы.Where

;

;

;

- constant signals.

или на

, которые равны нулю, обращаются в ноль. В результате в числителе и знаменателе выражений (7) и (8) останутся слагаемые, содержащие произведение передаточных функций схем выделения к-й гармонической составляющей. Выражение (7) и (8) преобразуется к виду:After that, we bring to the common denominator the expressions of the numerator and denominator in expressions (7) and (8) and replace the complex variable S with jω _k . As a result, all terms of the numerator and denominator of expressions (7) and (8) multiplied by

or at

, which are equal to zero, vanish. As a result, in the numerator and denominator of expressions (7) and (8) there will remain terms containing the product of the transfer functions of the allocation schemes of the k-th harmonic component. Expression (7) and (8) is converted to the form:

;

;, то это означает, что амплитуда к-й гармонической составляющей в d- и q-составляющих напряжения на нагрузке также равна нулю. Таким образом происходит исключение к-й гармонической составляющей в d- и q-составляющих напряжения на нагрузке.If the quantities

;

;, then this means that the amplitude of the k-th harmonic component in the d- and q-components of the voltage at the load is also equal to zero. Thus, the kth harmonic component is excluded in the d- and q-components of the voltage at the load.

Arguing in a similar way, it can be shown that with the proposed control method, the quality of the generated electric power is increased by eliminating the d- and q-components of the voltage at the load of all the selected harmonic components. This eliminates the reverse sequence of voltage at the load, since it is it that creates harmonic components in the d- and q-components of the voltage at the load.

A similar result is obtained if a link of the form is used as a scheme for separating the harmonic components of the d- and q-components of the voltage at the load of a three-phase asymmetric value:

We determine the values of the constant signals in the d- and q-components of the voltage at the load. To do this, we represent the transfer functions of the integral regulators of the d- and q-components of the voltage at the load in the form:

We select the transfer functions of the integral regulators of the d- and q-components of the voltage at the load in the numerators and denominators of expressions (7) and (8), we bring the numerators and denominators in these expressions to a common denominator and take S = 0. As a result, we get the expressions:

From the expressions (14) after the transformations, we can obtain:

Recent expressions show that when using the dq coordinate system, switching to constant voltage signals and comparing comparison signals by integrating the corresponding differences, the stabilization accuracy of the d and q components of the voltage at the load and, therefore, the parameters of the direct sequence signals is determined only by the instability of the corresponding reference signals and proportionality factors. The accuracy of stabilization of the direct sequence parameters does not depend on the parameters of the power circuit and the finiteness of the gain of the control loops and therefore will be higher than in the prototype method.

Figure 2 presents the simulation results in Matlab Simulink of a bridge voltage inverter that generates a voltage of 400 Hz and an effective phase voltage of 115 V (on-board aircraft electrical energy generation system), without adjusting the harmonic components of the d- and q-components of the voltage at the load. The switching frequency of the inverter keys is 20 kHz. Active load resistances for phases A, B and C are respectively 2 Ohms, 3 kOhms and 3 kOhms. The reference signal for the d-component corresponds to the nominal value of the voltage at the load, and the reference signal for the q-component is zero. Figure 2 shows the phase voltage of the load (first graph), d- (upper curve) and q- (lower curve) components of the load voltage (second graph) and the zero sequence of the load voltage (third graph). Figure 3 presents the curves similar to those in figure 2 when implementing the proposed control method and highlighting the second harmonic components of the d- and q-components of the voltage at the load. The simulation results show that the maximum second harmonic component is excluded in the d- and q-components of the voltage at the load, and confirm the effectiveness of the proposed control method.

Thus, the proposed control method allows to improve the quality of the generated electricity, firstly, by eliminating the negative sequence from a three-phase signal with an unbalanced load and, secondly, by increasing the accuracy of stabilization of the direct sequence.

Claims (1)

A vector way to control a three-phase static converter with an asymmetric load, which consists in measuring the instantaneous values of the three-phase output value of the converter, voltage or current, converting the measured value from a three-phase abc coordinate system to a two-phase coordinate system, for generating a two-phase coordinate system, generate reference signals, form comparison signals, form regulatory signals that convert from a two-phase coordinate system to a three-phase abc coordinate system, proportional For the newly converted signals, a three-phase modulating signal of the converter is generated, characterized in that the three-phase output quantity is converted into a dq coordinate system rotating at a constant frequency of the fundamental harmonic component of the output quantity Ω, and zero reference signals of harmonic components for the d and q components of the output quantity are generated, for d-component of the output value, the reference signal is formed according to the nominal value of the output quantity, the reference signal of the q-component of the output led values are formed by zero, the above comparison signals of the d- and q-components of the output quantity are formed by integrating the differences of the corresponding reference signals and signals proportional to the d- and q-components of the output quantity, the difference signals are generated by subtracting signals proportional to the d- and q-components the output value from the corresponding reference signals of the harmonic components, in the difference signals for the d- and q-components of the output value, the harmonic components with a large coefficient ylene, and said regulating signals for the d- and q-components of the output value is formed by summing the respective comparison signals and the selected harmonic component for the d- and q-components of the output value.

Images