JP2013093987A - Phase adjustment device, system counter component generation device, system interconnection inverter system, and phase adjustment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phase adjustment device which can appropriately adjust the phase of a signal even when the signal has an opposite phase component superposed therein.SOLUTION: In a phase adjustment device, the phases of three signals based on the system voltage in each phase of a three-phase AC are adjusted. The phase adjustment device comprises: a three-phase/two-phase conversion unit 81 which converts three voltage signals detected by a voltage sensor into an α axis voltage signal and a β axis voltage signal; a positive phase component extraction unit 82' which extracts a signal for the positive phase components of the α axis and the β axis voltage signals; a negative phase component extraction unit 83' which extracts a signal for the negative phase components of the α axis and the β axis voltage signals; a positive phase component phase adjustment unit 84 which adjusts the phase of the extracted positive phase component signal; a negative phase component phase adjustment unit 85 which adjusts the phase of the extracted negative phase component signal; and a two-phase/three-phase conversion unit 87 which generates three adjusted signals from the phase-adjusted positive phase component and negative phase component signals which have been added together.

Description

  The present invention relates to a phase adjusting device for adjusting a phase delay in advance, a system counter component generating device including the phase adjusting device, a system interconnection inverter system including the system counter component generating device, and phase adjustment Regarding the method.

  2. Description of the Related Art Conventionally, a grid-connected inverter system has been developed that converts DC power generated by a solar cell or the like into AC power and supplies it to an electric power system.

  FIG. 17 is a block diagram for explaining a conventional general grid-connected inverter system.

  The grid-connected inverter system A100 converts the DC power generated by the DC power source 1 into AC power and supplies it to the three-phase power system B. Hereinafter, the three phases are referred to as a U phase, a V phase, and a W phase.

  The inverter circuit 2 converts a DC voltage input from the DC power supply 1 into an AC voltage by switching a switching element (not shown). The filter circuit 3 removes a switching frequency component included in the AC voltage output from the inverter circuit 2. The transformer circuit 4 boosts (or steps down) the AC voltage output from the filter circuit 3 to the system voltage of the power system B. The control circuit 700 receives the current signal and the voltage signal detected by the current sensor 5 and the voltage sensor 6, generates a PWM signal based on the current signal and the voltage signal, and outputs the PWM signal to the inverter circuit 2. The inverter circuit 2 performs switching of the switching element based on the PWM signal input from the control circuit 700.

  The control circuit 700 includes a current control unit 71, a system counter component generation unit 800, and a PWM signal generation unit 72. The current control unit 71 generates and outputs correction value signals Xu, Xv, Xw for current control based on the current signal I (Iu, Iv, Iw) input from the current sensor 5. Based on the voltage signal V (Vu, Vv, Vw) input from the voltage sensor 6, the system counter component generation unit 800 generates and outputs system command value signals Yu, Yv, Yw. Command value signals X′u, X′v, X′w obtained by adding the system command value signals Yu, Yv, Yw and the correction value signals Xu, Xv, Xw, respectively, are input to the PWM signal generation unit 72. The PWM signal generation unit 72 generates PWM signals Pu, Pv, Pw based on the input command value signals X′u, X′v, X′w, and outputs them to the inverter circuit 2.

  In processing such as filter detection such as the filter circuit 3 and voltage detection, a phase delay occurs. Processing for eliminating the inconvenience due to the phase delay is performed by the system counter-part generating unit 800. For example, a method of generating system command value signals Yu, Yv, Yw in which voltage changes due to phase delay are increased or decreased in advance, or the phase of system command value signals Yu, Yv, Yw is advanced in advance by the amount of phase delay. The method of putting it is proposed.

JP-A-9-271176

  However, since the power system B includes an AC signal for the negative phase in addition to the AC signal for the positive phase of the fundamental wave, the phase adjustment method cannot properly adjust the phase. . That is, the system command value signals Yu, Yv, Yw based on the voltage signal V input from the voltage sensor 6 also include signals for opposite phases. When the process of advancing the phase of the signal for the positive phase of the system command value signals Yu, Yv, Yw is performed, the phase of the signal for the reverse phase whose phase sequence is opposite to that of the signal for the positive phase is delayed. become. As a result, the phase of the anti-phase signal is greatly delayed because the phase is delayed by a filter and the phase is further delayed. In this case, it becomes difficult to cause the system command value signals Yu, Yv, Yw output from the system counter-part generating unit 800 to accurately follow the system voltage of the power system B.

  In particular, when the reverse phase of the power system B increases due to system disturbance such as a momentary drop, the tracking accuracy becomes worse. As a result, a difference occurs between the grid voltage and the output voltage of the grid-connected inverter system, and an overcurrent flows. When an overcurrent flows, the grid-connected inverter system is stopped and disconnected from the power system B. Thereby, the system disturbance of the electric power system B will be expanded.

  The present invention has been conceived under the circumstances described above, and provides a phase adjustment device capable of appropriately adjusting the phase of a signal even when a reverse phase component is superimposed on the signal. That is the purpose.

  In order to solve the above problems, the present invention takes the following technical means.

  The phase adjustment device provided by the first aspect of the present invention is a phase adjustment device that adjusts the phases of three signals based on a three-phase alternating current, and has a phase opposite to that of a positive phase signal based on the three signals. Extraction means for extracting each of the minute signals, a positive phase phase adjusting means for adjusting the phase of the positive phase signal extracted by the extraction means, and a negative phase signal extracted by the extraction means It is characterized by comprising anti-phase phase adjusting means for adjusting the phase, and synthesizing means for generating three adjusted signals from the positive phase signal and the anti-phase signal after phase adjustment. Note that the “positive phase signal” is a signal having the same frequency and the same phase order as the three-phase AC fundamental wave, and the “negative phase signal” is a three-phase AC fundamental wave and frequency. The signals are the same but in reverse phase order.

  In a preferred embodiment of the present invention, the extraction means includes a three-phase / two-phase conversion means for converting the three signals into a first signal and a second signal, and a positive phase included in the first signal. A first positive phase signal that is a minute signal, a first negative phase signal that is a negative phase signal included in the first signal, and a positive phase component that is included in the second signal. A signal extraction unit that extracts a second positive phase signal that is a signal and a second negative phase signal that is a reverse phase signal included in the second signal, and the synthesis unit includes: The first adjusted signal obtained by adding the first positive phase signal after phase adjustment and the first negative phase signal after phase adjustment, the second positive phase signal after phase adjustment, and the phase adjustment An adding means for generating a second adjusted signal obtained by adding the second second-phase signal after the second adjustment signal; A second adjusted signal and a two-phase three-phase conversion means for converting the three adjusted signal.

In a preferred embodiment of the present invention, the signal extraction means performs signal processing on the first signal with a first transfer function, and processes the second signal with a second transfer function. First positive phase component extracting means for extracting the first positive phase component signal by addition, signal processing of the first signal by a third transfer function, and processing of the second signal to the first signal Signal processing by a transfer function, and adding the second positive phase signal by adding these, and processing the first signal by the first transfer function, Signal processing of the second signal by the third transfer function, and adding them, the first antiphase component extracting means for extracting the first antiphase component signal; and the first signal of the first signal Signal processing with a second transfer function, and And a second antiphase component extracting means for extracting the second antiphase signal by adding these signals to the signal, and calculating the angular frequency of the fundamental wave of the three-phase alternating current. When ω ₀ and the time constant is T, the first transfer function is G ₁ (s) = (T · s + 1) / {(T · s + 1) ² + (T · ω ₀ ) ² }, The second transfer function is G ₂ (s) = − T · ω ₀ / {(T · s + 1) ² + (T · ω ₀ ) ² }, and the third transfer function is G ₃ ( s) = T · ω ₀ / {(T · s + 1) ² + (T · ω ₀ ) ² }.

In a preferred embodiment of the present invention, the signal extraction means performs signal processing on the first signal with a first transfer function, and processes the second signal with a second transfer function. First positive phase component extracting means for extracting the first positive phase component signal by addition, signal processing of the first signal by a third transfer function, and processing of the second signal to the first signal Signal processing by a transfer function, and adding the second positive phase signal by adding these, and processing the first signal by the first transfer function, Signal processing of the second signal by the third transfer function, and adding them, the first antiphase component extracting means for extracting the first antiphase component signal; and the first signal of the first signal Signal processing with a second transfer function, and And a second antiphase component extracting means for extracting the second antiphase signal by adding these signals to the signal, and calculating the angular frequency of the fundamental wave of the three-phase alternating current. When ω ₀ and the time constant are T, the first transfer function is G ₁ (s) = (T ² · s ² + T · s + T ² · ω ₀ ² ) / {(T · s + 1) ² + ( T · ω ₀ ) ² }, and the second transfer function is G ₂ (s) = − T · ω ₀ / {(T · s + 1) ² + (T · ω ₀ ) ² }, The third transfer function is G ₃ (s) = T · ω ₀ / {(T · s + 1) ² + (T · ω ₀ ) ² }.

  In a preferred embodiment of the present invention, the signal extraction means performs a rotation coordinate conversion process on the first signal and the second signal based on a reference phase that is a phase of a sine wave signal as a reference. Thus, a positive phase rotational coordinate conversion means for generating a positive phase d-axis signal and a positive phase q-axis signal, and a negative reference that is a negative value of the reference phase in the first signal and the second signal. By performing a rotation coordinate conversion process based on the phase, a negative phase rotation coordinate conversion means for generating a negative phase d axis signal and a negative phase q axis signal, the positive phase d axis signal, the positive phase q axis signal, Filter means for passing only a negative-phase d-axis signal and a direct-current component of the negative-phase q-axis signal, a direct-current component of the positive-phase d-axis signal that has passed through the filter means, and a direct-current component of the positive-phase q-axis signal Next, a stationary coordinate conversion process based on the reference phase is performed. Thus, the positive phase stationary coordinate conversion means for generating the first positive phase signal and the second positive phase signal, the direct current component of the negative phase d-axis signal that has passed through the filter means, and the negative phase A negative phase stationary coordinate that generates the first negative phase component signal and the second negative phase component signal by performing a stationary coordinate conversion process based on the negative reference phase on the DC component of the q-axis signal. Conversion means.

In a preferred embodiment of the present invention, the signal extraction means has the first positive phase signal Xαp and the second positive phase, where Xα is the first signal and Xβ is the second signal. The divided signal Xβp is calculated by a determinant expressed by the following equation (1a), and the first antiphase component signal Xαn and the first antiphase signal Xβn are calculated by a determinant expressed by the following equation (1b).

In a preferred embodiment of the present invention, the extraction means is extracted by a signal extraction means for extracting a positive phase signal and a negative phase signal included in the three signals, respectively, and the signal extraction means. Three positive phase signals are converted into a first positive phase signal and a second positive phase signal, and the extracted three negative phase signals are converted into a first negative phase signal and a second reverse phase signal. And a three-phase / two-phase conversion means for converting the signal into a phase signal, and the combining means adds the first positive phase signal after phase adjustment and the first reverse phase signal after phase adjustment. Adding means for generating a first adjusted signal, a second adjusted signal obtained by adding the second positive phase signal after the phase adjustment and the second negative phase signal after the phase adjustment; Two-phase three-phase for converting the first adjusted signal and the second adjusted signal into the three adjusted signals Conversion means, and the signal extraction means, when the three signals are Xu, Xv, and Xw, the signals Xup, Xvp, and Xwp for the three positive phases are represented by a determinant represented by the following equation (2a): And three signals Xun, Xvn, and Xwn for opposite phases are extracted by a determinant represented by the following equation (2b).

In a preferred embodiment of the present invention, the positive phase component phase adjusting means has the first positive phase signal as Xαp, the second positive phase signal as Xβp, and the phase adjustment amount as θ ₀ . The first positive phase signal X′αp and the second positive phase signal X′βp after the phase adjustment are calculated by a determinant represented by the following equation (3), When the first negative phase signal is Xαn, the second negative phase signal is Xβn, and the phase adjustment amount is θ ₀ , the first negative phase signal X′αn and the second negative phase signal after phase adjustment The minute signal X′βn is calculated by a determinant represented by the following equation (4).

  In a preferred embodiment of the present invention, there is further provided an amplitude adjusting means for adjusting the amplitudes of the first adjusted signal and the second adjusted signal.

  The system counter-generation device provided by the second aspect of the present invention is the voltage of each phase of the three-phase power system detected by the voltage detection means by the phase adjustment device provided by the first aspect of the present invention. The signal phase is adjusted and output.

  The grid interconnection inverter system provided by the third aspect of the present invention is based on the voltage signal of each phase after the phase adjustment output from the grid counter component generation apparatus provided by the second aspect of the present invention. A control circuit that generates and outputs a PWM signal and an inverter circuit that converts DC power into AC power based on the PWM signal input from the control circuit are provided.

  The phase adjustment method provided by the fourth aspect of the present invention is a phase adjustment method for adjusting the phases of three signals based on three-phase alternating current, and is in phase with a signal corresponding to the positive phase based on the three signals. A first step for extracting the minute signal, a second step for adjusting the phase of the positive phase signal extracted by the first step, and a reverse phase extracted by the first step. A third step of adjusting the phase of the minute signal, and a fourth step of generating three adjusted signals from the positive phase signal and the negative phase signal after the phase adjustment. Features.

  According to the present invention, the signal for the positive phase and the signal for the negative phase are respectively extracted, the phase of the signal for the positive phase is adjusted by the phase adjustment means for the positive phase, and the signal of the negative phase is The phase is adjusted by the phase adjusting means. Then, three adjusted signals are generated from the signals whose phases are adjusted. Since the phase of the signal for the positive phase and the signal for the negative phase are adjusted using a method suitable for each, even when the negative phase component is superimposed on the signal based on the three-phase alternating current, the phase of the signal is adjusted. It can be adjusted appropriately.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

It is a block diagram for demonstrating the grid connection inverter system which concerns on 1st Embodiment. It is a block diagram for demonstrating the internal structure of the system | strain opposing part production | generation part which concerns on 1st Embodiment. It is a figure for demonstrating the simulation result performed in 1st Embodiment. It is a figure for demonstrating the simulation result performed in 1st Embodiment. It is a figure for demonstrating the simulation result performed in 1st Embodiment. It is a block diagram for demonstrating the method to convert the process accompanied by a rotation coordinate transformation and a stationary coordinate transformation into a linear time invariant process. It is a block diagram for demonstrating the method to convert the process accompanied by a rotation coordinate transformation and a stationary coordinate transformation into a linear time invariant process, and is represented by the matrix. It is a block diagram for demonstrating the calculation of a matrix. It is a block diagram which shows the process which performs a static coordinate transformation after performing a low-pass filter process after performing a rotational coordinate transformation. It is a Bode diagram for analyzing a transfer function which is each element of matrix G _LPF . It is a figure for demonstrating the signal for a positive phase, and the signal for a reverse phase. It is a block diagram for demonstrating the internal structure of the system | strain opposing part production | generation part which concerns on 2nd Embodiment. It is a block diagram which shows the process which performs a static coordinate transformation after performing a high-pass filter process after performing a rotational coordinate transformation. It is a Bode diagram for analyzing a transfer function which is each element of matrix G _HPF . It is a block diagram for demonstrating the internal structure of the system | strain countermeasure production | generation part which concerns on 3rd Embodiment. It is a block diagram for demonstrating the internal structure of the system | strain countermeasure production | generation part which concerns on 4th Embodiment. It is a block diagram for demonstrating the conventional general grid connection inverter system.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings, taking as an example a case where the phase adjusting device according to the present invention is used in a system counter-component generating unit of a system interconnection inverter system.

  FIG. 1 is a block diagram for explaining a grid-connected inverter system according to the first embodiment.

  As shown in the figure, the grid-connected inverter system A includes a DC power source 1, an inverter circuit 2, a filter circuit 3, a transformer circuit 4, a current sensor 5, a voltage sensor 6, and a control circuit 7.

  The DC power source 1 is connected to the inverter circuit 2. The inverter circuit 2, the filter circuit 3, and the transformer circuit 4 are connected in series to the output lines of the U-phase, V-phase, and W-phase output voltages in this order, and connected to the three-phase AC power system B. Yes. The current sensor 5 and the voltage sensor 6 are installed on the output side of the transformer circuit 4. The control circuit 7 is connected to the inverter circuit 2. The grid interconnection inverter system A converts the DC power output from the DC power supply 1 into AC power and supplies it to the power grid B. In addition, the structure of the grid connection inverter system A is not restricted to this. For example, the current sensor 5 and the voltage sensor 6 may be provided on the input side of the transformer circuit 4, or other sensors necessary for controlling the inverter circuit 2 may be provided. Further, the transformer circuit 4 may be provided on the input side of the filter circuit 3, or a so-called transformer-less system in which the transformer circuit 4 is not provided. Further, a DC / DC converter circuit may be provided between the DC power supply 1 and the inverter circuit 2.

  The DC power source 1 outputs DC power and includes, for example, a solar battery. A solar cell generates direct-current power by converting solar energy into electrical energy. The DC power source 1 outputs the generated DC power to the inverter circuit 2. Note that the DC power source 1 is not limited to one that generates DC power from a solar cell. For example, the DC power source 1 may be a fuel cell, a storage battery, an electric double layer capacitor, a lithium ion battery, or AC power generated by a diesel engine generator, a micro gas turbine generator, a wind turbine generator, or the like. It may be a device that converts to DC power and outputs it.

  The inverter circuit 2 converts a DC voltage input from the DC power source 1 into an AC voltage and outputs the AC voltage to the filter circuit 3. The inverter circuit 2 is a three-phase inverter, and is a PWM control type inverter circuit including three sets of six switching elements (not shown). The inverter circuit 2 converts the DC voltage input from the DC power source 1 into an AC voltage by switching each switching element on and off based on the PWM signal input from the control circuit 7. In addition, the inverter circuit 2 is not limited to this, For example, a multilevel inverter may be sufficient.

  The filter circuit 3 removes high frequency components due to switching from the AC voltage input from the inverter circuit 2. The filter circuit 3 includes a low pass filter including a reactor and a capacitor. The AC voltage from which the high frequency component has been removed by the filter circuit 3 is output to the transformer circuit 4. The configuration of the filter circuit 3 is not limited to this, and any known filter circuit for removing high frequency components may be used. The transformer circuit 4 boosts or lowers the AC voltage output from the filter circuit 3 to a level substantially the same as the system voltage.

  The current sensor 5 detects the alternating current of each phase output from the transformer circuit 4 (that is, the output current of the grid interconnection inverter system A). The detected current signal I (Iu, Iv, Iw) is input to the control circuit 7. The voltage sensor 6 detects the system voltage of each phase of the power system B. The detected voltage signal V (Vu, Vv, Vw) is input to the control circuit 7. Note that the output voltage output by the grid interconnection inverter system A substantially matches the grid voltage.

  The control circuit 7 controls the inverter circuit 2 and is realized by, for example, a microcomputer. The control circuit 7 generates a PWM signal based on the current signal I input from the current sensor 5 and the voltage signal V input from the voltage sensor 6 and outputs the PWM signal to the inverter circuit 2. The control circuit 7 generates a command value signal for commanding the waveform of the output voltage output from the grid interconnection inverter system A based on the detection signal input from each sensor, and is generated based on the command value signal. Output a pulse signal as a PWM signal. The inverter circuit 2 outputs an alternating voltage having a waveform corresponding to the command value signal by switching each switching element on and off based on the input PWM signal. The control circuit 7 controls the output current by changing the waveform of the command value signal to change the waveform of the output voltage of the grid interconnection inverter system A. Thereby, the control circuit 7 performs various feedback controls. The command value signal is generated by adding a compensation signal for current control to a signal based on the voltage signal V detected by the voltage sensor 6.

  In FIG. 1, only the configuration for performing output current control is described, and the configuration for other control is omitted. Actually, the control circuit 7 performs DC voltage control (feedback control performed so that the input DC voltage becomes a preset voltage target value) and reactive power control (reactive power target value with preset output reactive power) (Feedback control to be performed) is also performed. The control method performed by the control circuit 7 is not limited to this. For example, output voltage control or active power control may be performed.

  The control circuit 7 includes a current control unit 71, a PWM signal generation unit 72, and a system counter component generation unit 8.

  The current control unit 71 generates correction value signals Xu, Xv, and Xw for current control based on the current signal I (Iu, Iv, Iw) input from the current sensor 5. The current control unit 71 is for performing feedback control for matching the current signals Iu, Iv, and Iw to the respective target values. The correction value signals Xu, Xv, and Xw are used as compensation signals for the control. Output. System command value signals Yu, Yv, Yw output from the system counter-part generating unit 8 to be described later and correction value signals Xu, Xv, Xw output from the current control unit 71 are added, respectively, to generate a command value signal X′u. , X′v, X′w are calculated and input to the PWM signal generator 72.

  The PWM signal generation unit 72 performs a triangular wave comparison based on the input command value signals X′u, X′v, and X′w and a carrier signal generated as a triangular wave signal having a predetermined frequency (for example, 4 kHz). PWM signals Pu, Pv, Pw are generated by the method. In the triangular wave comparison method, the command value signals X′u, X′v, and X′w are respectively compared with the carrier signal. For example, when the command value signal X′u is larger than the carrier signal, the high level is obtained. A low-level pulse signal is generated as the PWM signal Pu. The generated PWM signals Pu, Pv, Pw are output to the inverter circuit 2.

  The system counter-part generating unit 8 receives the voltage signal V (Vu, Vv, Vw) from the voltage sensor 6 and generates and outputs the system command value signals Yu, Yv, Yw. The system command value signals Yu, Yv, Yw are used as references for the command value signals X′u, X′v, X′w for commanding the waveform of the output voltage output from the grid interconnection inverter system A. The command value signals X′u, X′v, and X′w are generated by correcting the system command value signals Yu, Yv, and Yw with the correction value signals Xu, Xv, and Xw. The system countermeasure generation unit 8 advances the phase delay delayed by the filter circuit 3 or the like, and generates system command value signals Yu, Yv, Yw. The system counter-part generation unit 8 extracts a signal for the normal phase and a signal for the reverse phase included in the voltage signal V, and performs a process of separately advancing the phase. The signal for the positive phase and the signal for the negative phase are added after their phases have been advanced.

  FIG. 2 is a block diagram for explaining the internal configuration of the system counter-part generating unit 8.

  As shown in the figure, the system conflict generation unit 8 includes a three-phase / two-phase conversion unit 81, a normal phase extraction unit 82, a negative phase extraction unit 83, a positive phase component phase adjustment unit 84, and a negative phase component phase. An adjustment unit 85, an amplitude adjustment unit 86, and a two-phase / three-phase conversion unit 87 are provided.

  The three-phase / two-phase converter 81 converts the three voltage signals Vu, Vv, Vw input from the voltage sensor 6 into an α-axis voltage signal Vα and a β-axis voltage signal Vβ. The three-phase / two-phase converter 81 performs a so-called three-phase / two-phase conversion process (αβ conversion process), and converts the voltage signals Vu, Vv, Vw into an α-axis component and a β-axis component that are orthogonal to each other. The α-axis voltage signal Vα and the β-axis voltage signal Vβ are generated by decomposing and combining the respective axis components.

The conversion process performed in the three-phase / two-phase conversion unit 81 is expressed by a determinant represented by the following equation (5).

  The positive phase component extraction unit 82 extracts the fundamental phase positive phase signal from the α-axis voltage signal Vα and the β-axis voltage signal Vβ input from the three-phase / two-phase conversion unit 81. The extracted positive phase signals Yαp and Yβp are output to the positive phase phase adjustment unit 84. The normal phase extraction unit 82 includes a rotation coordinate conversion unit 82a, an LPF 82b, and a stationary coordinate conversion unit 82c.

  The rotation coordinate conversion unit 82a converts the α-axis voltage signal Vα and the β-axis voltage signal Vβ input from the three-phase / two-phase conversion unit 81 into a d-axis voltage signal Vdp and a q-axis voltage signal Vqp in the rotation coordinate system. Is. The rotating coordinate system is an orthogonal coordinate system having orthogonal d-axis and q-axis and rotating in the same direction at the same angular velocity as the fundamental wave of the system voltage of the power system B. As a concept opposite to the rotating coordinate system, a non-rotating coordinate system is a stationary coordinate system. The rotation coordinate conversion unit 82a performs a so-called rotation coordinate conversion process (dq conversion process), and the system voltage detected by the phase detection unit (not shown) detects the α-axis voltage signal Vα and the β-axis voltage signal Vβ of the stationary coordinate system. Is converted into a d-axis voltage signal Vdp and a q-axis voltage signal Vqp of the rotating coordinate system.

The conversion process performed by the rotation coordinate conversion unit 82a is represented by a determinant represented by the following expression (6).

  The LPF 82b is a low-pass filter and passes only the DC components of the d-axis voltage signal Vdp and the q-axis voltage signal Vqp. Through the rotation coordinate conversion process, the positive phase components of the α-axis voltage signal Vα and the β-axis voltage signal Vβ are converted into DC components of the d-axis voltage signal Vdp and the q-axis voltage signal Vqp, respectively. The LPF 82b passes only the direct current component and cuts off the alternating current component, thereby passing the positive phase component signal of the fundamental wave and blocking other component signals (negative phase signal and harmonic signal). The DC component signal Ydp of the d-axis voltage signal Vdp and the DC component signal Yqp of the q-axis voltage signal Vqp are output to the stationary coordinate conversion unit 82c.

  The stationary coordinate conversion unit 82c converts the DC component signals Ydp and Yqp input from the LPF 82b into two normal phase signals Yαp and Yβp in the stationary coordinate system, and is the inverse conversion of the rotational coordinate conversion unit 82a. The processing is performed. The stationary coordinate conversion unit 82c performs a so-called stationary coordinate conversion process (inverse dq conversion process), and converts the DC component signals Ydp and Yqp of the rotating coordinate system into the normal phase signal of the stationary coordinate system based on the phase θ. Convert to Yαp, Yβp.

The conversion process performed by the stationary coordinate conversion unit 82c is represented by a determinant represented by the following expression (7).

  The anti-phase component extracting unit 83 extracts an anti-phase component signal of the fundamental wave from the α-axis voltage signal Vα and the β-axis voltage signal Vβ input from the three-phase / two-phase conversion unit 81. The extracted antiphase component signals Yαn and Yβn are output to the antiphase component phase adjustment unit 85. The reverse phase extraction unit 83 includes a rotation coordinate conversion unit 83a, an LPF 83b, and a stationary coordinate conversion unit 83c.

  The rotation coordinate conversion unit 83a uses the α-axis voltage signal Vα and the β-axis voltage signal Vβ input from the three-phase / two-phase conversion unit 81 as the d-axis voltage signal Vdn and the q-axis voltage signal of the rotation coordinate system for the reverse phase. It converts to Vqn. The rotating coordinate system for the reverse phase is an orthogonal coordinate system that rotates in the opposite direction at the same angular velocity as the fundamental wave of the system voltage of the power system B. The rotation coordinate conversion unit 83a performs a so-called rotation coordinate conversion process (dq conversion process), and converts the α-axis voltage signal Vα and the β-axis voltage signal Vβ of the stationary coordinate system to the negative of the phase θ of the fundamental wave of the system voltage. Is converted into the d-axis voltage signal Vdn and the q-axis voltage signal Vqn of the rotating coordinate system for the opposite phase.

The conversion process performed by the rotation coordinate conversion unit 83a is expressed by a determinant represented by the following equation (8).

  The LPF 83b is a low-pass filter and passes only the DC components of the d-axis voltage signal Vdn and the q-axis voltage signal Vqn. By the rotation coordinate conversion process for the reverse phase, the reverse phase components of the fundamental wave of the α-axis voltage signal Vα and the β-axis voltage signal Vβ are converted into DC components of the d-axis voltage signal Vdn and the q-axis voltage signal Vqn, respectively. . The LPF 83b passes only the direct current component and blocks the alternating current component, thereby passing the negative phase component of the fundamental wave and blocking other component signals (positive phase signal and harmonic signal). The DC component signal Ydn of the d-axis voltage signal Vdn and the DC component signal Yqn of the q-axis voltage signal Vqn are output to the stationary coordinate converter 83c.

  The stationary coordinate conversion unit 83c converts the DC component signals Ydn and Yqn input from the LPF 83b into two opposite phase signals Yαn and Yβn in the stationary coordinate system, and is the inverse conversion from the rotational coordinate conversion unit 83a. The processing is performed. The static coordinate conversion unit 83c performs a so-called static coordinate conversion process (inverse dq conversion process), and converts the DC component signals Ydn and Yqn of the rotating coordinate system to the inverse of the static coordinate system based on the phase (−θ). It converts into phase signal Yαn, Yβn.

The conversion process performed by the static coordinate conversion unit 83c is represented by a determinant represented by the following expression (9).

The phase adjustment unit 84 for the positive phase adjusts the phase so that the delayed phase is advanced in advance. The phase to be delayed is acquired in advance by experiments, and a phase adjustment amount θ ₀ for adjusting this is set. That is, when the phase is delayed by θ _{0 due to} a filter or the like, the positive phase phase adjustment unit 84 performs a process of advancing the phase of the positive phase signals Yαp and Yβp by the phase adjustment amount θ ₀ to correct the positive phase after the phase adjustment. Phase separation signals Y′αp and Y′βp are output.

The phase adjustment process performed by the phase adjustment unit 84 for the positive phase is expressed by a determinant represented by the following equation (10).

Note that the processing performed by the stationary coordinate conversion unit 82c and the processing performed by the positive phase phase adjustment unit 84 may be performed by one processing. That is, when stationary coordinate conversion is performed by the stationary coordinate conversion unit 82c, processing for advancing the phase by the phase adjustment amount θ ₀ may be performed.

The process in the case where the stationary coordinate conversion process and the phase adjustment process are performed at once is expressed by the determinant represented by the following expression (11) from the above expressions (7) and (10).

The antiphase component phase adjustment unit 85 adjusts the phase so that the delayed phase is advanced in advance. When the phase is delayed by θ _{0 by a} filter or the like, the anti-phase component phase adjustment unit 85 performs a process of advancing the phase of the anti-phase signal signals Yαn and Yβn by the phase adjustment amount θ ₀ so that the anti-phase component after phase adjustment is performed. Signals Y′αn and Y′βn are output.

When the phase of the signal of the opposite phase is advanced by the phase adjustment amount θ ₀ , a matrix in which θ ₀ is (−θ ₀ ) is used in the matrix shown in the above equation (10). That is, the phase adjustment process performed by the antiphase component phase adjustment unit 85 is represented by a determinant represented by the following equation (12).

The process performed by the stationary coordinate conversion unit 83c and the process performed by the antiphase phase adjustment unit 85 may be performed by one process. That is, when stationary coordinate conversion is performed by the stationary coordinate conversion unit 83c, processing for advancing the phase by the phase adjustment amount θ ₀ may be performed.

The process in the case where the stationary coordinate conversion process and the phase adjustment process are performed at once is expressed by the determinant represented by the following expression (13) from the above expressions (9) and (12).

  A signal Y′α obtained by adding the positive phase signal Y′αp output from the positive phase phase adjustment unit 84 and the negative phase signal Y′αn output from the reverse phase phase adjustment unit 85, and a positive phase signal A signal Y′β obtained by adding Y′βp and the antiphase signal Y′βn is input to the amplitude adjusting unit 86. The amplitude adjusting unit 86 adjusts the amplitude of the signals Y′α and Y′β, performs a process of amplifying the amount attenuated by the filter, and outputs the signals Yα and Yβ after amplitude adjustment.

  The two-phase / three-phase converter 87 converts the signals Yα and Yβ output from the amplitude adjuster 86 into three system command value signals Yu, Yv, and Yw. The two-phase / three-phase conversion unit 87 performs a so-called two-phase / three-phase conversion process (reverse αβ conversion process), and performs a conversion process opposite to the three-phase / two-phase conversion unit 81.

The conversion process performed by the two-phase / three-phase converter 87 is expressed by a determinant represented by the following equation (14).

  In the present embodiment, the system counter-part generating unit 8 converts the voltage signals Vu, Vv, and Vw into an α-axis voltage signal Vα and a β-axis voltage signal Vβ, and the positive phase signals Yαp and Yβp and the negative phase signal Yαn, Yβn is extracted. Then, the phases of the positive phase signals Yαp and Yβp are adjusted by the positive phase component phase adjustment unit 84, and the phases of the negative phase signals Yαn and Yβn are adjusted by the negative phase component phase adjustment unit 85. Each signal whose phase has been adjusted is added and the amplitude is adjusted, and then converted into three system command value signals Yu, Yv, Yw by two-phase / three-phase conversion. Since the signal for the positive phase and the signal for the negative phase with different phase adjustment methods are extracted and phase-adjusted by a method suitable for each, even if the negative phase component is superimposed on the system voltage, the system counter component generation The unit 8 can output a system command value signal whose phase is appropriately adjusted.

  3-5 is a figure for demonstrating the simulation result performed in this embodiment.

First, it was verified whether the system command value signals Yu, Yv, Yw output from the system counter-part generating unit 8 can accurately follow the system voltage of the power system B. Therefore, the simulation is performed with the phase adjustment amount θ ₀ = 0. FIG. 3 shows the waveforms of the interconnection point voltage (corresponding to the system voltage) and the system counter component (corresponding to the system command value signal) in this simulation for each phase. The figure (a) is the thing of the U phase, the figure (b) is the thing of the V phase, and the figure (c) is the thing of the W phase. After a lapse of 0.2 seconds from the start of the simulation, a voltage drop was applied, and a reverse phase component was further applied. As shown in FIGS. 5A to 5C, the system counter-measurement component follows the interconnection point voltage at high speed with high accuracy in each phase.

Next, it was verified whether the phase could be adjusted. FIG. 4 shows, for each phase, the waveform of the interconnection point voltage and the system counter voltage in the simulation when the phase is advanced. The simulation is performed under the same conditions as the simulation except that the phase adjustment amount θ ₀ = 30 degrees. Further, FIG. 5 shows the waveform of the interconnection point voltage and the system opposition for each phase in the simulation when the phase is delayed. The simulation is performed under the same conditions as the simulation except that the phase adjustment amount θ ₀ = −30 degrees. As shown in FIG. 4 and FIG. 5, the system opposition component follows the interconnection point voltage at high speed with high accuracy and appropriately adjusts the phase. That is, the phase of the system command value signal can be appropriately adjusted even in a state where the antiphase component is superimposed on the system voltage.

  In the first embodiment, the case where the low-pass filter is used has been described, but the high-pass filter may be used.

  In this case, if the positive phase component extraction unit 82 shown in FIG. 2 removes the reverse phase component using a high-pass filter, and the reverse phase component extraction unit 83 removes the positive phase component using a high-pass filter. Good. That is, the rotation coordinate conversion unit 82a performs rotation coordinate conversion for the reverse phase based on the phase (−θ), cuts the DC component (reverse phase component) with a high-pass filter instead of the LPF 82b, and the stationary coordinate conversion unit 82c The stationary coordinate transformation is performed based on the phase (−θ). Further, the rotation coordinate conversion unit 83a performs rotation coordinate conversion based on the phase θ, cuts off the DC component (positive phase component) with a high-pass filter instead of the LPF 83b, and the stationary coordinate conversion unit 83c performs the stationary coordinate conversion based on the phase θ. Make the conversion. Even in this case, the positive phase component extraction unit 82 can extract the fundamental phase positive phase signal, and the negative phase component extraction unit 83 can extract the fundamental phase negative phase signal.

  In the first embodiment, since the rotational coordinate conversion units 82a and 83a and the static coordinate conversion units 82c and 83c perform nonlinear time-varying processing, the control system cannot be designed using linear control theory. System analysis was not possible. A case in which the rotation coordinate conversion units 82a and 83a and the stationary coordinate conversion units 82c and 83c are not provided so that the linear control theory can be used and an alternative configuration is adopted will be described as a second embodiment.

  First, a method for converting processing involving rotational coordinate transformation and stationary coordinate transformation into linear time-invariant processing will be described.

  FIG. 6A is a diagram for explaining processing involving rotational coordinate conversion and stationary coordinate conversion. In this processing, first, the signals α and β are converted into signals d and q by rotational coordinate conversion. The signals d and q are each processed by a predetermined transfer function F (s), and signals d 'and q' are output. Next, the signals d ′ and q ′ are converted into signals α ′ and β ′ by stationary coordinate transformation. The nonlinear time-varying process shown in FIG. 6A is converted into a process using the matrix G of the linear time-invariant transfer function shown in FIG. 6B.

The rotational coordinate transformation shown in FIG. 6A is represented by a determinant of the following equation (15), and the stationary coordinate transformation is represented by a determinant of the following equation (16).

  Therefore, the process shown in FIG. 6A can be expressed as shown in FIG. 7A using a matrix. The matrix G shown in FIG. 6B can be calculated by calculating the product of the three matrices shown in FIG. 7A and making the calculated matrix a linear time-invariant matrix. At this time, the calculation is performed after converting the matrix of the stationary coordinate conversion and the rotation coordinate conversion into a matrix product.

The matrix of rotational coordinate conversion can be converted into a product of the right-hand side matrix shown in the following equation (17).
Where j is the imaginary unit, exp () is the exponential function of the base e of the natural logarithm,
It is. T ⁻¹ is an inverse matrix of T.

From the Euler's formula, calculating by substituting exp (jθ) = cos θ + jsin θ and exp (−jθ) = cos θ−jsin θ,
It can be confirmed that

Further, the matrix of the static coordinate conversion can be converted into the product of the right-side matrix shown in the following equation (18). The matrix in the middle of the matrix product is a linear time-invariant matrix.
Where j is the imaginary unit, exp () is the exponential function of the base e of the natural logarithm,
It is. T ⁻¹ is an inverse matrix of T.

From the Euler's formula, calculating by substituting exp (jθ) = cos θ + jsin θ and exp (−jθ) = cos θ−jsin θ,
It can be confirmed that

When the product of the three matrices shown in FIG. 7A is calculated using the above equations (17) and (18) and the matrix G is calculated, the following equation (19) is obtained.

When attention is paid to the element in the first row and the first column of the three matrixes in the center of the above equation (19) and this is expressed in a block diagram, the block diagram shown in FIG. 8 is obtained. When calculating the input / output characteristics of the block diagram shown in FIG.
It becomes. Where F (s) is a one-input one-output transfer function having an impulse response f (t).

Here, when θ (t) = ω ₀ t, θ (t) −θ (τ) = ω ₀ t−ω ₀ τ = ω ₀ (t−τ) = θ (t−τ). The input / output characteristics of the block diagram shown in FIG. 8 are equal to those of a linear time invariant system having an impulse response f (t) exp (−jω ₀ t). When the impulse response f (t) exp (−jω ₀ t) is Laplace transformed, a transfer function F (s + jω ₀ ) is obtained. The input / output characteristics when exp (jθ (t)) and exp (−jθ (t)) in the block diagram shown in FIG. 8 are interchanged are the input / output characteristics of the transfer function F (s−jω ₀ ). become.

Therefore, when the calculation is further advanced from the above equation (19),
Is calculated.

  Thereby, the process shown in FIG. 7A can be converted into the process shown in FIG. The process shown in FIG. 7B is a process equivalent to the process of performing the stationary coordinate conversion after performing the process represented by the predetermined transfer function F (s) after performing the rotational coordinate conversion. This system is a linear time-invariant system.

The transfer function of the low-pass filter is represented by F (s) = 1 / (Ts + 1), where T is the time constant. Therefore, the transfer function matrix G _LPF showing the process shown in FIG. 9, that is, the process equivalent to the process of performing the static coordinate conversion after the low-pass filter process after performing the rotary coordinate conversion, is expressed by the above equation (20). And is calculated as shown in the following equation (21).

FIG. 10 is a Bode diagram for analyzing a transfer function that is each element of the matrix G _LPF . FIG. 5A shows a 1-row and 1-column element of matrix G _LPF (hereinafter referred to as “(1,1) element”. Other elements are also described in the same manner) and (2,2) element. It shows a transfer function, Fig. (b) shows a transfer function of (1,2) element of the matrix G _LPF, FIG. (c) the transfer function of the (2,1) element of the matrix G _LPF Is shown. The figure shows the case where the frequency of the fundamental wave of the system voltage (hereinafter referred to as “center frequency”. Also, the angular frequency corresponding to the center frequency is referred to as “center angular frequency”) is 60 Hz (that is, angular frequency). ω ₀ = 120π), and the time constant T is set to “0.1”, “1”, “10”, “100”.

The amplitude characteristics shown in FIGS. 4A, 4B, and 5C all have a peak at the center frequency, and the peak of the amplitude characteristic is −6 dB (= 1/2). Further, as the time constant T increases, the pass band decreases. The phase characteristic shown in FIG. 5A is 0 degree at the center frequency. That is, the transfer function of the (1, 1) element and the (2, 2) element of the matrix G _LPF passes the signal of the center frequency (center angular frequency) without changing the phase. The phase characteristic shown in FIG. 5B is 90 degrees at the center frequency. That is, the transfer function of the (1,2) element of the matrix G _LPF passes the phase of the signal of the center frequency (center angular frequency) by 90 degrees. On the other hand, the phase characteristic shown in FIG. 4C is −90 degrees at the center frequency. That is, the transfer function of the (2, 1) element of the matrix G _LPF passes the signal of the center frequency (center angular frequency) delayed by 90 degrees. Hereinafter, processing shown in the transfer function matrix G _LPF for the two signals after the three-phase / two-phase conversion will be discussed with reference to FIG.

    FIG. 11 is a diagram for explaining the signal for the positive phase and the signal for the negative phase. FIG. 4A shows the signal for the positive phase, and FIG. 4B shows the signal for the reverse phase.

In FIG. 9A, the positive phase components of the fundamental wave of the voltage signals Vu, Vv, Vw are indicated by broken line arrows vectors u, v, w. The vectors u, v, and w have directions different from each other by 120 degrees, and are arranged in a clockwise order and rotated counterclockwise at an angular frequency ω ₀ . The α-axis signal and β-axis signal obtained by converting the positive phase signal into three-phase / two-phase signals are indicated by vectors α and β of solid arrows. The vectors α and β are different in direction by 90 degrees in the clockwise order, and are rotated counterclockwise at the angular frequency ω ₀ .

That is, the α-axis signal is 90 degrees ahead of the β-axis signal. When the processing indicated by the transfer function of the (1, 1) element of the matrix G _LPF is performed on the α-axis signal, the amplitude becomes half and the phase does not change (see FIG. 10A). Further, when the process indicated by the transfer function of the (1,2) element of the matrix G _LPF is performed on the β-axis signal, the amplitude is halved and the phase is advanced by 90 degrees (see FIG. 10B). Therefore, since both phases are the same as the α-axis signal, the α-axis signal is reproduced by adding both. On the other hand, when the process indicated by the transfer function of the (2, 1) element of the matrix G _LPF is performed on the α-axis signal, the amplitude is halved and the phase is delayed by 90 degrees (see FIG. 10C). Further, when the process indicated by the transfer function of the (2, 2) element of the matrix G _LPF is performed on the β-axis signal, the amplitude becomes half and the phase does not change. Therefore, since both phases are the same as the β-axis signal, the β-axis signal is reproduced by adding both.

The reverse phase component is a component whose phase sequence is opposite to the normal phase component. In FIG. 11 (b), the antiphase signal of the fundamental wave of the voltage signals Vu, Vv, Vw is indicated by the vectors u, v, w of broken line arrows. The vectors u, v, and w have directions different from each other by 120 degrees, and are arranged in the counterclockwise order and rotated in the counterclockwise direction at the angular frequency ω ₀ . An α-axis signal and a β-axis signal obtained by three-phase / two-phase conversion of the antiphase signal are indicated by vectors α and β of solid arrows. The vectors α and β are different in the direction of 90 degrees in the counterclockwise order, and rotate in the counterclockwise direction at the angular frequency ω ₀ .

That is, the α-axis signal is 90 degrees behind the β-axis signal. When the processing indicated by the transfer function of the (1, 1) element of the matrix G _LPF is performed on the α-axis signal, the amplitude becomes half and the phase does not change. Further, when the process indicated by the transfer function of the (1,2) element of the matrix G _LPF is performed on the β-axis signal, the amplitude becomes half and the phase advances by 90 degrees. Therefore, since the phases of both are reversed, adding them together cancels each other. On the other hand, when the processing indicated by the transfer function of the (2, 1) element of the G _LPF is performed on the α-axis signal, the amplitude is halved and the phase is delayed by 90 degrees. Further, when the process indicated by the transfer function of the (2, 2) element of the matrix G _LPF is performed on the β-axis signal, the amplitude becomes half and the phase does not change. Therefore, since the phases of both are reversed, adding them together cancels each other. In other words, the transfer function matrix G _LPF passes the positive phase signal of the fundamental wave and blocks the negative phase signal. In addition, since a signal having a frequency other than the fundamental wave (such as a harmonic) is attenuated by the fundamental wave, the process indicated by the transfer function matrix G _LPF may be a filter process for extracting a positive-phase component signal of the center frequency. I can confirm.

When the (1, 2) element and the (2, 1) element of the transfer function matrix G _LPF are interchanged, conversely to the above, the positive phase signal is cut off and the negative phase signal is passed. Therefore, when extracting the antiphase signal of the center frequency, a matrix obtained by exchanging the (1, 2) element and the (2, 1) element of the transfer function matrix G _LPF may be used.

  FIG. 12 is a block diagram for explaining an internal configuration of a system counter-part generating unit according to the second embodiment. In this figure, the same or similar elements as those of the system counter-part generating unit 8 shown in FIG.

  The system conflict generation unit 8 ′ shown in FIG. 12 includes a normal phase extraction unit 82 ′ and a reverse phase extraction unit 83 ′ instead of the normal phase extraction unit 82 and the reverse phase extraction unit 83. Thus, it is different from the system conflict generation unit 8 (see FIG. 2) according to the first embodiment.

The positive phase component extraction unit 82 ′ extracts a fundamental phase positive phase signal from the α-axis voltage signal Vα and the β-axis voltage signal Vβ input from the three-phase / two-phase conversion unit 81. The extracted positive phase signals Yαp and Yβp are output to the positive phase phase adjustment unit 84. The positive phase component extraction unit 82 ′ performs the process represented by the transfer function matrix G _LPF for extracting the positive phase component signal of the fundamental wave shown in the equation (21). That is, the process shown in the following equation (22) is performed. As the angular frequency ω _{0, the} angular frequency of the fundamental wave of the system voltage (for example, ω ₀ = 120π [rad / sec] (60 [Hz])) is set in advance, and the time constant T is designed in advance.

In the present embodiment, the normal phase extraction unit 82 ′ performs the filtering process in the stationary coordinate system without performing the rotation coordinate conversion and the stationary coordinate conversion. The transfer function matrix G _LPF is a transfer function matrix indicating a process equivalent to a process of performing a stationary coordinate conversion after performing a filtering process after performing a rotation coordinate conversion. Therefore, the positive phase component extraction unit 82 ′ that performs the process represented by the transfer function matrix G _LPF is equivalent to the rotation coordinate conversion unit 82a, the stationary coordinate conversion unit 82c, and the LPF 82b shown in FIG. A process equivalent to the phase extraction unit 82 is performed.

In addition, the processing performed by the positive phase component extraction unit 82 ′ is a linear time-invariant processing because it is represented by a transfer function matrix G _LPF . Since the system is a linear time invariant system that does not include the rotating coordinate transformation process and the static coordinate transformation process, which are nonlinear time-varying processes, control system design and system analysis using linear control theory are possible. Thus, by using the matrix G _{LPF of the} transfer function shown in the above equation (21), nonlinear processing that performs stationary coordinate transformation after performing filtering processing after performing rotational coordinate transformation can be performed in a linear time invariant manner. It can be reduced to the input / output system, which facilitates system analysis and control system design.

The negative phase component extraction unit 83 ′ extracts a basic phase negative phase signal from the α-axis voltage signal Vα and the β-axis voltage signal Vβ input from the three-phase / two-phase conversion unit 81. The extracted antiphase component signals Yαn and Yβn are output to the antiphase component phase adjustment unit 85. The antiphase component extraction unit 83 ′ performs processing represented by a matrix in which the (1,2) element and the (2,1) element of the transfer function matrix G _LPF shown in the above equation (21) are interchanged. That is, the process for extracting the antiphase signal of the fundamental wave is performed, and the process shown in the following equation (23) is performed. As the angular frequency ω _{0, the} angular frequency of the fundamental wave of the system voltage (for example, ω ₀ = 120π [rad / sec] (60 [Hz])) is set in advance, and the time constant T is designed in advance.

  The reverse phase extraction unit 83 'performs a process equivalent to the rotation coordinate conversion unit 83a, the static coordinate conversion unit 83c, and the LPF 83b shown in FIG. 2, that is, a process equivalent to the reverse phase extraction unit 83. In addition, the processing performed by the antiphase component extraction unit 83 ′ is also a linear time-invariant processing, which enables control system design and system analysis using linear control theory.

  The normal phase extraction unit 82 ′ and the reverse phase extraction unit 83 ′ perform processing equivalent to that of the normal phase extraction unit 82 and the reverse phase extraction unit 83 (see FIG. 2) according to the first embodiment, respectively. . That is, the positive phase component extraction unit 82 ′ extracts the positive phase component signals Yαp and Yβp from the α-axis voltage signal Vα and the β-axis voltage signal Vβ, and the negative phase component extraction unit 83 ′ extracts the α-axis voltage signal Vα and the β-axis voltage. The negative phase signals Yαn and Yβn are extracted from the signal Vβ. The phases of the positive phase signals Yαp and Yβp are adjusted by the positive phase component phase adjustment unit 84, and the phases of the negative phase signals Yαn and Yβn are adjusted by the negative phase component phase adjustment unit 85. Therefore, the system conflict generation unit 8 ′ according to the second embodiment can achieve the same effects as the system counter generation unit 8 according to the first embodiment. Furthermore, the system counter-part generating unit 8 ′ according to the second embodiment can also achieve an effect that control system design and system analysis using linear control theory are possible.

  In the present embodiment, the case where the time constants of the elements of the transfer function matrix are the same has been described, but different values may be used for each element. For example, it can be designed to provide additional characteristics such as improving the quick response of the α-axis component and increasing the stability.

  In the present embodiment, the case where the normal phase extraction unit 82 'and the reverse phase extraction unit 83' are individually designed has been described. However, the present invention is not limited to this. The common phase extraction unit 82 ′ and the reverse phase extraction unit 83 ′ may be designed at a time so as to share the time constant T.

In the present embodiment, the case where the angular frequency ω ₀ used in the normal phase extraction unit 82 ′ and the reverse phase extraction unit 83 ′ is set in advance has been described, but the present invention is not limited to this. When the sampling period of the signal processing is a fixed sampling period, the angular frequency of the fundamental wave of the system voltage may be detected by a frequency detection device or the like, and the detected angular frequency may be used as the angular frequency ω ₀ .

  In the present embodiment, the case of performing processing in place of the low-pass filter has been described, but a configuration in which processing in place of the high-pass filter is performed may be employed.

The transfer function of the high-pass filter is represented by F (s) = Ts / (Ts + 1), where T is the time constant. Therefore, the transfer function matrix G _HPF showing the process shown in FIG. 13, that is, the process equivalent to the process of performing the static coordinate conversion after performing the high-pass filter process after performing the rotation coordinate conversion is expressed by the above equation (20). And is calculated as shown in the following equation (24).

FIG. 14 is a Bode diagram for analyzing a transfer function which is each element of the matrix G _HPF . FIG (a) shows a transfer function of (1, 1) element and (2,2) element of the matrix G _HPF, FIG (b) the transfer function of the (1,2) element of the matrix G _HPF FIG. 4C shows the transfer function of the (2, 1) element of the matrix G _HPF . This figure shows the case where the center frequency is 60 Hz, and the time constant T is “0.1”, “1”, “10”, “100”.

The amplitude characteristic shown in FIG. 6A is attenuated in the vicinity of the center frequency, and the amplitude characteristic at the center frequency is −6 dB (= ½). Further, as the time constant T increases, the cutoff band decreases. The amplitude characteristics shown in FIGS. 5B and 5C both have a peak at the center frequency, and the peak of the amplitude characteristics is −6 dB (= ½). Further, as the time constant T increases, the pass band decreases. Further, the phase characteristic shown in FIG. 5A is 0 degree at the center frequency. That is, the transfer function of the (1, 1) element and the (2, 2) element of the matrix G _HPF passes the signal of the center frequency without changing the phase. The phase characteristic shown in FIG. 5B is −90 degrees at the center frequency. That is, the transfer function of the (1,2) element of the matrix G _HPF passes the signal of the center frequency signal delayed by 90 degrees. On the other hand, the phase characteristic shown in FIG. 4C is 90 degrees at the center frequency. That is, the transfer function of the (2, 1) element of the matrix G _HPF passes the phase of the signal at the center frequency by 90 degrees. The processing shown in the matrix G _{HPF of the} transfer function for the two signals after the three-phase / two-phase conversion will be discussed below with reference to FIG.

In FIG. 11A, when the processing indicated by the transfer function of the (1, 1) element of the matrix G _HPF is performed on the α-axis signal (vector α) obtained by three-phase / two-phase conversion of the positive phase signal of the fundamental wave The amplitude is halved and the phase does not change (see FIG. 14A). Further, when the process indicated by the transfer function of the (1,2) element of the matrix G _HPF is performed on the β-axis signal (vector β), the amplitude is halved and the phase is delayed by 90 degrees (see FIG. 14B). ). Therefore, since the phases of both are reversed, adding them together cancels each other. On the other hand, when the process indicated by the transfer function of the (2, 1) element of the matrix G _HPF is performed on the α-axis signal, the amplitude is halved and the phase is advanced by 90 degrees (see FIG. 14C). Further, when the process indicated by the transfer function of the (2, 2) element of the matrix G _HPF is performed on the β-axis signal, the amplitude becomes half and the phase does not change. Therefore, since the phases of both are reversed, adding them together cancels each other.

In FIG. 5B, when the processing shown in the transfer function of the (1, 1) element of the matrix G _HPF is performed on the α-axis signal (vector α) obtained by three-phase / two-phase conversion of the inverse signal of the fundamental wave. The amplitude is halved and the phase does not change. Further, when the process indicated by the transfer function of the (1,2) element of the matrix G _HPF is performed on the β-axis signal (vector β), the amplitude is halved and the phase is delayed by 90 degrees. Therefore, since both phases are the same as the α-axis signal, the α-axis signal is reproduced by adding both. On the other hand, when the process indicated by the transfer function of the (2, 1) element of the matrix G _HPF is performed on the α-axis signal, the amplitude is halved and the phase is advanced by 90 degrees (see FIG. 14C). Further, when the process indicated by the transfer function of the (2, 2) element of the matrix G _HPF is performed on the β-axis signal, the amplitude becomes half and the phase does not change. Therefore, since both phases are the same as the β-axis signal, the β-axis signal is reproduced by adding both.

That is, the matrix G _{HPF of the} transfer function allows the negative phase signal of the fundamental wave to pass and blocks the positive phase signal. In addition, a signal having a frequency other than the fundamental wave (such as a harmonic wave) passes as it is when the processing indicated by the transfer functions of the (1, 1) element and the (2, 2) element of the matrix G _HPF is performed (FIG. 14). (See (a)), (1) and (2,1) elements, and the transfer function of the (2,1) element is attenuated (see FIGS. 14 (b) and 14 (c)) and passes almost as it is. . Therefore, it can be confirmed that the process shown in the matrix G _HPF of the transfer function is a notch filter process that removes only the positive phase signal of the center frequency.

When the (1,2) element and the (2,1) element of the matrix G _HPF of the transfer function are interchanged, the reverse phase signal is cut off and the positive phase signal is passed, contrary to the above. Therefore, in order to remove only the antiphase signal of the center frequency, a matrix in which the (1,2) element and the (2,1) element of the transfer function matrix G _HPF are exchanged may be used.

In the second embodiment, when performing processing in place of the high-pass filter, the positive-phase component extracting unit 82 ′ shown in FIG. 12 performs processing in place of the high-pass filter to remove the anti-phase component, and the anti-phase component extracting unit 83 ′. However, the processing for replacing the high-pass filter may be performed to remove the positive phase component. That is, the reverse phase extraction unit 83 ′ performs the process shown in the following equation (25) using the matrix G _HPF shown in the above equation (24), and the normal phase extraction unit 82 ′ shows the above equation (24). The processing shown in the following equation (26) using a matrix in which the (1,2) and (2,1) elements of the matrix G _HPF are exchanged is performed. As the angular frequency ω ₀ , the angular frequency of the fundamental wave of the system voltage (for example, ω ₀ = 120π [rad / sec] (60 [Hz])) is set in advance, and the time constant T is designed in advance. . Even in this case, the positive phase component extraction unit 82 ′ can extract the fundamental phase positive phase signal, and the negative phase component extraction unit 83 ′ can extract the fundamental phase negative phase signal.

  Symmetric coordinate transformation is known as a method for extracting a normal phase signal and a negative phase signal. Hereinafter, a case where the positive phase signals Yαp and Yβp and the negative phase signals Yαn and Yβn are extracted from the α-axis voltage signal Vα and the β-axis voltage signal Vβ by using symmetric coordinate transformation will be described as a third embodiment. To do.

  FIG. 15 is a diagram for explaining the internal configuration of the system counter-part generating unit according to the third embodiment. In this figure, the same or similar elements as those of the system counter-part generating unit 8 shown in FIG.

  The system conflict generation unit 8 ″ shown in FIG. 15 includes an extraction unit 88 in place of the normal phase extraction unit 82 and the reverse phase extraction unit 83, and the system counter generation according to the first embodiment. Different from the part 8 (see FIG. 2).

The extraction unit 88 extracts the positive phase signal Yαp, Yβp and the negative phase signal Yαn, Yβn from the α-axis voltage signal Vα and the β-axis voltage signal Vβ input from the three-phase / two-phase conversion unit 81. It is. The extracted positive phase signals Yαp and Yβp are output to the positive phase component phase adjustment unit 84, and the extracted negative phase signals Yαn and Yβn are output to the negative phase component phase adjustment unit 85. The extraction unit 88 calculates the positive phase signals Yαp and Yβp from the α-axis voltage signal Vα and the β-axis voltage signal Vβ by the determinant represented by the following equation (27a), and the inverse by the determinant represented by the following equation (27b): Phase separation signals Yαn and Yβn are calculated. However, j is an imaginary unit. The following formulas (27a) and (27b) can be calculated from the following formulas (28a), (28b), (29), and (30), which will be described later, but a detailed description of the calculation process is omitted. To do.

  The extraction unit 88 extracts the positive-phase component signals Yαp and Yβp and the negative-phase component signals Yαn and Yβn from the α-axis voltage signal Vα and the β-axis voltage signal Vβ using the above equations (27a) and (27b). . The phases of the positive phase signals Yαp and Yβp are adjusted by the positive phase component phase adjustment unit 84, and the phases of the negative phase signals Yαn and Yβn are adjusted by the negative phase component phase adjustment unit 85. Therefore, the system counter-part generating unit 8 ″ according to the third embodiment can also achieve the same effects as the system counter-part generating unit 8 according to the first embodiment.

  In the third embodiment, the positive phase signal and the negative phase signal are extracted after the three-phase / two-phase conversion, but the positive phase signal and the negative phase signal are extracted first. After that, three-phase / two-phase conversion may be performed. In the fourth embodiment, the normal phase signal and the negative phase signal are extracted from the voltage signal V (Vu, Vv, Vw) using symmetric coordinate transformation, and then the three-phase / two-phase transformation is performed. This will be described as a form.

  FIG. 16 is a diagram for explaining the internal configuration of the system counter-part generating unit according to the fourth embodiment. In the figure, the same or similar elements as those of the system counter-part generating unit 8 ″ shown in FIG.

  The system counter component generation unit 8 ′ ″ shown in FIG. 16 performs the three-phase / two-phase conversion after extracting the positive phase signal and the negative phase signal, and thus the system counter component according to the third embodiment. Unlike the generation unit 8 ″ (see FIG. 15), instead of the three-phase / two-phase conversion unit 81 and the extraction unit 88, an extraction unit 88 ′ and three-phase / two-phase conversion units 81′a and 81′b are provided. Yes.

The extraction unit 88 ′ extracts the positive phase signals Yup, Yvp, Ywp and the negative phase signals Yun, Yvn, Ywn of each phase from the voltage signal V (Vu, Vv, Vw) input from the voltage sensor 6. To do. The extracted normal phase signals Yup, Yvp, Ywp are output to the three-phase / two-phase converter 81′a, and the extracted negative-phase signals Yun, Yvn, Ywn are three-phase / two-phase converter 81′b. Is output. The extraction unit 88 ′ performs processing shown in the following equations (28a) and (28b). However, a = exp (j · 2π / 3), exp () is an exponential function of the base e of the natural logarithm, and j is an imaginary unit.

The three-phase / two-phase conversion unit 81′a converts the three positive phase signals Yup, Yvp, Ywp input from the extraction unit 88 ′ into two positive phase signals Yαp, Yβp. The converted positive phase signals Yαp and Yβp are output to the positive phase phase adjusting unit 84. The three-phase / two-phase conversion unit 81′a performs a so-called three-phase / two-phase conversion process (αβ conversion process). The conversion process performed by the three-phase / two-phase conversion unit 81′a is as follows (29 ) Expressed by the determinant shown in the equation.

The three-phase / two-phase converter 81′b converts the three anti-phase signals Yun, Yvn, Ywn input from the extractor 88 ′ into two anti-phase signals Yαn, Yβn. The converted antiphase signal Yαn, Yβn is output to the antiphase component phase adjustment unit 85. The three-phase / two-phase conversion unit 81′b performs a so-called three-phase / two-phase conversion process (αβ conversion process). The conversion process performed by the three-phase / two-phase conversion unit 81′b is as follows (30 ) Expressed by the determinant shown in the equation.

  The extraction unit 88 ′ and the three-phase / two-phase conversion units 81′a and 81′b are connected to the positive phase signals Yup, Yvp, Ywp and the negative phase signal Yun of each phase from the voltage signal V (Vu, Vv, Vw). , Yvn, Ywn are extracted and converted into the positive phase signals Yαp, Yβp and the negative phase signals Yαn, Yβn, respectively. The phases of the positive phase signals Yαp and Yβp are adjusted by the positive phase component phase adjustment unit 84, and the phases of the negative phase signals Yαn and Yβn are adjusted by the negative phase component phase adjustment unit 85. Therefore, the system counter-part generating unit 8 ′ ″ according to the fourth embodiment can also achieve the same effects as the system counter-part generating unit 8 according to the first embodiment.

  In the first to fourth embodiments, the case where the phase adjustment device according to the present invention is used for the system counter-component generation unit has been described, but the present invention is not limited to this. For example, when the phase of the current signal I (Iu, Iv, Iw) input to the current control unit 71 (see FIG. 1) is adjusted, or the correction value signals Xu, Xv, Xw output from the current control unit 71 The phase adjusting device according to the present invention can also be used when adjusting the phase.

  In the first to fourth embodiments, the case where the phase adjusting device according to the present invention is used in a grid-connected inverter system has been described. However, the present invention is not limited to this. The phase adjusting device according to the present invention can be used for adjusting the phase of a signal in any device or configuration using a signal based on a three-phase alternating current. For example, three-phase AC such as harmonic compensator, active filter for power, unbalance compensator, static reactive power compensator (SVC, SVG), uninterruptible power supply (UPS), power factor compensator, frequency converter, etc. The phase adjusting device according to the present invention can also be used in a device that handles the above.

  The phase adjustment device, system counter-component generation device, system interconnection inverter system, and phase adjustment method according to the present invention are not limited to the above-described embodiments. The specific configuration of each part of the phase adjustment device, the system counter component generation device, the system interconnection inverter system, and the phase adjustment method according to the present invention can be varied in design in various ways.

A Grid-connected inverter system 1 DC power supply 2 Inverter circuit 3 Filter circuit 4 Transformer circuit 5 Current sensor 6 Voltage sensor 7 Control circuit 71 Current control unit 72 PWM signal generation unit 8, 8 ′, 8 ″, 8 ′ ″ System opposition Minute generation unit 81, 81′a, 81′b Three-phase / two-phase conversion unit 82, 82 ′ Positive phase extraction unit (signal extraction means, first positive phase extraction means, second positive phase extraction means)
82a Rotation coordinate conversion unit (normal phase rotation coordinate conversion means)
82b LPF (filter means)
82c Stationary coordinate conversion unit (normal phase stationary coordinate conversion means)
83, 83 ′ negative phase extraction unit (signal extraction means, first negative phase extraction means, second negative phase extraction means)
83a Rotation coordinate conversion unit (reverse phase rotation coordinate conversion means)
83b LPF (filter means)
83c Stationary coordinate converter (reverse phase stationary coordinate converter)
84 Positive phase component phase adjustment unit 85 Negative phase component phase adjustment unit 86 Amplitude adjustment unit 87 Two-phase / three-phase conversion unit 88, 88 ′ Extraction unit (signal extraction means)
B Power system

Claims (12)

A phase adjustment device for adjusting the phases of three signals based on a three-phase alternating current,
Extraction means for extracting a signal for a normal phase and a signal for a negative phase based on the three signals,
Positive phase phase adjusting means for adjusting the phase of the positive phase signal extracted by the extracting means;
Anti-phase phase adjusting means for adjusting the phase of the anti-phase signal extracted by the extracting means;
A synthesizing means for generating three adjusted signals from the signal for the positive phase and the signal for the negative phase after the phase adjustment;
A phase adjustment device comprising: The extraction means includes
Three-phase to two-phase conversion means for converting the three signals into a first signal and a second signal;
A first positive phase signal that is a positive phase signal included in the first signal; a first negative phase signal that is a negative phase signal included in the first signal; A signal for extracting a second positive phase signal that is a positive phase signal included in the second signal and a second negative phase signal that is a negative phase signal included in the second signal, respectively. Extraction means;
With
The synthesis means includes
The first adjusted signal obtained by adding the first positive phase signal after phase adjustment and the first negative phase signal after phase adjustment, and the second positive phase signal after phase adjustment and the phase adjusted Adding means for generating a second adjusted signal obtained by adding the second antiphase signal of
Two-phase three-phase conversion means for converting the first adjusted signal and the second adjusted signal into the three adjusted signals;
With
The phase adjusting device according to claim 1. The signal extraction means includes
The first signal is signal-processed by a first transfer function, the second signal is signal-processed by a second transfer function, and these are added to extract the first positive phase signal. 1 positive phase extraction means;
The first signal is signal-processed by a third transfer function, the second signal is signal-processed by the first transfer function, and these are added to extract the second positive phase signal. Second positive phase extraction means;
The first signal is signal-processed by the first transfer function, the second signal is signal-processed by the third transfer function, and these are added to extract the first antiphase signal. First reverse phase extraction means for
The first signal is signal-processed by the second transfer function, the second signal is signal-processed by the first transfer function, and these are added to extract the second antiphase signal. Second reverse phase extraction means for
With
When the angular frequency of the fundamental wave of the three-phase alternating current is ω ₀ and the time constant is T,
The first transfer function is:
G ₁ (s) = (T · s + 1) / {(T · s + 1) ² + (T · ω ₀ ) ² }
And
The second transfer function is
G ₂ (s) = − T · ω ₀ / {(T · s + 1) ² + (T · ω ₀ ) ² }
And
The third transfer function is
G ₃ (s) = T · ω ₀ / {(T · s + 1) ² + (T · ω ₀ ) ² }
Is,
The phase adjusting device according to claim 2. The signal extraction means includes
The first signal is signal-processed by a first transfer function, the second signal is signal-processed by a second transfer function, and these are added to extract the first positive phase signal. 1 positive phase extraction means;
The first signal is signal-processed by a third transfer function, the second signal is signal-processed by the first transfer function, and these are added to extract the second positive phase signal. Second positive phase extraction means;
The first signal is signal-processed by the first transfer function, the second signal is signal-processed by the third transfer function, and these are added to extract the first antiphase signal. First reverse phase extraction means for
The first signal is signal-processed by the second transfer function, the second signal is signal-processed by the first transfer function, and these are added to extract the second antiphase signal. Second reverse phase extraction means for
With
When the angular frequency of the fundamental wave of the three-phase alternating current is ω ₀ and the time constant is T,
The first transfer function is:
G ₁ (s) = (T ² · s ² + T · s + T ² · ω ₀ ² ) / {(T · s + 1) ² + (T · ω ₀ ) ² }
And
The second transfer function is
G ₂ (s) = − T · ω ₀ / {(T · s + 1) ² + (T · ω ₀ ) ² }
And
The third transfer function is
G ₃ (s) = T · ω ₀ / {(T · s + 1) ² + (T · ω ₀ ) ² }
Is,
The phase adjusting device according to claim 2. The signal extraction means includes
A positive phase d-axis signal and a positive phase q-axis signal are generated by subjecting the first signal and the second signal to a rotation coordinate conversion process based on a reference phase that is a phase of a sine wave signal as a reference. A normal phase rotation coordinate conversion means,
By performing a rotation coordinate conversion process based on a negative reference phase that is a negative value of the reference phase on the first signal and the second signal, a negative-phase d-axis signal and a negative-phase q-axis signal are obtained. A reverse phase rotation coordinate conversion means to generate,
Filter means for passing only the DC component of the positive phase d-axis signal, the positive phase q-axis signal, the negative phase d-axis signal, and the negative phase q-axis signal;
By performing a stationary coordinate conversion process based on the reference phase on the DC component of the positive phase d-axis signal and the DC component of the positive phase q-axis signal that have passed through the filter means, the first positive phase component A positive phase stationary coordinate transformation means for generating a signal and the second positive phase component signal;
By performing a stationary coordinate transformation process based on the negative reference phase on the DC component of the anti-phase d-axis signal and the DC component of the anti-phase q-axis signal that have passed through the filter means, the first inverse Antiphase stationary coordinate transformation means for generating a phase signal and the second antiphase signal; and
The phase adjustment device according to claim 2, comprising: The signal extraction means sets the first positive phase signal Xαp and the second positive phase signal Xβp to the following equation (1a), where Xα is the first signal and Xβ is the second signal: The phase adjustment apparatus according to claim 2, wherein the first negative phase component signal Xαn and the first negative phase component signal Xβn are calculated by a determinant represented by the following equation (1b).
The extraction means includes
Signal extraction means for extracting a signal for a positive phase and a signal for a negative phase included in the three signals, respectively;
The three positive phase signals extracted by the signal extraction means are converted into a first positive phase signal and a second positive phase signal, and the extracted three negative phase signals are converted into a first reverse phase signal. Three-phase to two-phase conversion means for converting into a phase signal and a second antiphase signal;
With
The synthesis means includes
The first adjusted signal obtained by adding the first positive phase signal after phase adjustment and the first negative phase signal after phase adjustment, and the second positive phase signal after phase adjustment and the phase adjusted Adding means for generating a second adjusted signal obtained by adding the second antiphase signal of
Two-phase three-phase conversion means for converting the first adjusted signal and the second adjusted signal into the three adjusted signals;
With
When the three signals are Xu, Xv, and Xw, the signal extraction means
Three positive phase signals Xup, Xvp, Xwp are extracted by the determinant shown in the following equation (2a),
Three anti-phase signals Xun, Xvn, and Xwn are extracted by a determinant represented by the following equation (2b).
The phase adjusting device according to claim 1.
The phase adjustment means for the positive phase is the first positive phase component after phase adjustment, where Xαp is the first positive phase signal, Xβp is the second positive phase signal, and θ ₀ is the phase adjustment amount. The signal X′αp and the second positive phase signal X′βp are calculated by a determinant represented by the following equation (3):
The negative phase component phase adjusting means is configured to set the first negative phase component signal to Xαn, the second negative phase component signal to Xβn, and the phase adjustment amount to θ _0. The signal X′αn and the second antiphase signal X′βn are calculated by a determinant represented by the following equation (4).
The phase adjustment device according to claim 2.
  9. The phase adjustment apparatus according to claim 2, further comprising an amplitude adjustment unit that adjusts amplitudes of the first adjusted signal and the second adjusted signal. 10.   System counter-component generation, characterized in that the phase of the voltage signal of each phase of the three-phase power system detected by the voltage detection means is adjusted and output by the phase adjustment device according to any one of claims 1 to 9. apparatus. A control circuit that generates and outputs a PWM signal based on the voltage signal of each phase after phase adjustment output from the system counter-component generating device according to claim 10;
An inverter circuit that converts DC power into AC power based on a PWM signal input from the control circuit;
A grid interconnection inverter system characterized by comprising: A phase adjustment method for adjusting the phases of three signals based on three-phase alternating current,
A first step of extracting a positive phase signal and a negative phase signal based on the three signals, respectively;
A second step of adjusting the phase of the positive phase signal extracted by the first step;
A third step of adjusting the phase of the anti-phase signal extracted by the first step;
A fourth step of generating three adjusted signals from the positive phase signal and the negative phase signal after the phase adjustment;
A phase adjustment method comprising: