JP5121514B2 - Overvoltage suppression control method by reverse phase control - Google Patents

Description

  The present invention relates to an overvoltage suppression control method by reverse phase control that suppresses system overvoltage when the voltage of an AC power system is unbalanced at the time of occurrence of an accident or during normal times and a system overvoltage is generated.

A power converter connected to the power system to convert AC power and DC power bidirectionally and to pulse width modulate the DC voltage can control the active power and reactive power of the power system. It is used for power interchange, voltage stabilization, and fluctuation compensation.
As a conventional power conversion device, when a grid fault occurs, the controllable element of the power converter is stopped, and the stop state is continued for the minimum time necessary to stop the system current. A technique is disclosed in which a controllable element of a converter is operated so that current can be passed (for example, Patent Document 1).
In another power converter control device, Non-Patent Document 1, for example, Document Y. Jiang, Å. Ekstrom, “Applying PWM to Control Overcurrents at Unbalanced Faults of Forced-Commutated VSCs Used as Static Var Compensators”, IEEE Transactions on Power Delivery, Vol. 12, no. 1, pp. As disclosed in 273-278, January 1997, the multiphase AC voltage is decomposed into a positive phase component and a negative phase component, and then the magnitude and phase of each phase voltage output command of the power converter is calculated to convert the power. The device is controlled (FIG. 6). In order to separate the positive phase component and the negative phase component, the multiphase AC voltage is converted into a quadrature two-phase AC voltage and is calculated from the 1/4 cycle delay signal (FIG. 2).

Japanese Patent Laid-Open No. 06-175741 (FIGS. 1 and 2) IEEE Transactions on Power Delivery, Vol. 12, no. 1, pp. 273-278, January 1997

In the conventional power conversion device disclosed in Patent Document 1, when the current of the power system is re-energized, the power system accident continues, and the power conversion device is a multiphase AC voltage of the power system. May be in an unbalanced state. For this reason, there is a problem that even if the controllable element is operated in this state and the operation of the power converter is restarted, there is no overvoltage suppression effect on the power system.
Further, in the control device for the power converter shown in Non-Patent Document 1, in order to separate the multiphase AC voltage into a normal phase component and a reverse phase component, a delay of at least 1/4 cycle occurs, and a 1/4 cycle occurs. In the following, there is a problem that the voltage of the power system cannot be obtained correctly, and the negative phase voltage cannot be suppressed against the generation of a transient negative phase voltage.

  The present invention has been made to solve the above-described problems, and suppresses overcurrent of the power conversion circuit even when the AC power system becomes unbalanced and an overvoltage due to a reverse phase voltage transiently occurs. However, an object of the present invention is to obtain an overvoltage suppression control system based on reverse phase control that can suppress overvoltage and operate at high speed.

  The present invention is connected to a power system, converts AC power and DC power bidirectionally, a power conversion circuit that performs pulse width modulation control on the DC voltage, an AC voltage detector that detects the voltage of the power system, AC current detector that detects the current flowing from the power conversion circuit to the power system, a phase detector that detects the reference phase from the detected value of the AC voltage detector, and the detected value of the AC current detector and the phase detector A current component detector that detects the active current component Id and the reactive current component Iq from the reference phase, a deviation between the active current command value Id * and the active current component Id, and the reactive current command value Iq * and the reactive current component Iq An amplifier that feedback-controls the output alternating current of the power conversion circuit using the output as a voltage command value of the power conversion circuit, and a voltage that detects the voltage amplitude and phase of each phase from the detection value of the AC voltage detector The voltage amplitude average value Vm and the phase average value Φm of the power system are calculated from the width phase detector and the voltage amplitude and phase of each phase detected by the voltage amplitude phase detector, and the voltage amplitude average value Vm, The phase average value Φm is converted by the first coordinate converter, the average value calculating means for calculating the average voltage components Vdm and Vqm, and the output value of the average value calculating means is added to convert the power output from the amplifier. A second coordinate converter that corrects the voltage command value of the circuit and calculates the corrected voltage commands Vd * and Vq * to AC three-phase system voltage values, a detected value of the voltage amplitude phase detector, and a voltage amplitude average A deviation calculating means for calculating the amplitude deviation and phase deviations ΔVa to ΔVc, ΔΦa to ΔΦc of the value Vm and the phase average value Φm, and the amplitude and phase deviations ΔVa to ΔVc and ΔΦa to ΔΦc are input, and the amplitude and phase deviation are input. ΔVa ~ An overcurrent suppression dead band device having first operation threshold values Vth1 and Φth1 for ΔVc and ΔΦa to ΔΦc and suppressing an overcurrent output from the power conversion circuit, and second operation threshold values Vth2 and Φth2 for deviations In the overvoltage suppression control system by the reverse phase control including the overvoltage suppression dead band suppressor that suppresses the overvoltage output from the power conversion circuit, Vth1> Vth2 is set, and the overcurrent suppression dead band has an amplitude and phase deviation ΔVa. When ΔVc, ΔΦa to ΔΦc exceed the first operating threshold values Vth1 and Φth1, overcurrent suppression dead band output values ΔVa to ΔVc and ΔΦa to ΔΦc that are equal to the deviation are output, and overvoltage The suppression dead band is an overvoltage suppression dead band when any of the amplitude and phase deviations ΔVa to ΔVc and ΔΦa to ΔΦc exceeds the second operation threshold values Vth2 and Φth2. Output values ΔVva to ΔVvc and ΔΦva to ΔΦvc are outputted, and deviations ΔVva to ΔVvc of the overvoltage suppression dead zone output values are subtracted from deviations ΔVa to ΔVc of the overcurrent suppression dead zone outputs, respectively. Deviations ΔVd to ΔVf, and deviations ΔΦva to ΔΦvc in the overvoltage suppression dead zone output values are subtracted from deviations ΔΦa to ΔΦc in the overcurrent suppression dead zone output values to obtain corrected phase deviations ΔΦd to ΔΦf. The value is calculated as a sine wave signal, and the sine wave signal and the correction voltage deviations ΔVd to ΔVf are multiplied by a multiplier, and the voltage command correction values ΔVa * to ΔVc * of the operation output are added to the output of the second coordinate converter. This is an overvoltage suppression control method based on reverse phase control of the power conversion circuit via a pulse width modulator that inputs the voltage command value by adding the voltage to a voltage command value of the power conversion circuit.

  An overvoltage suppression control method using reverse phase control according to the present invention includes an AC voltage detector that detects a voltage of a power system, an AC current detector that detects a current flowing from the power conversion circuit to the power system, and an AC voltage detector. A phase detector for detecting a reference phase from the detection value; a current component detector for detecting an active current component Id and a reactive current component Iq from the detection value of the AC current detector and the reference phase detected by the phase detector; The deviation between the active current command value Id * and the active current component Id, the reactive current command value Iq * and the reactive current component Iq is amplified, and the output is the voltage command value of the power conversion circuit, and the output AC current of the power conversion circuit An amplifier for feedback control, a voltage amplitude phase detector for detecting the voltage amplitude and phase of each phase from the detection value of the AC voltage detector, and the voltage amplitude of each phase detected by this voltage amplitude phase detector From the phase, the voltage amplitude average value Vm and the phase average value Φm of the power system are calculated, and the voltage amplitude average value Vm and the phase average value Φm are converted by the first coordinate converter to obtain an average voltage component Vdm, The average value calculating means for calculating Vqm and the output value of the average value calculating means are added to correct the voltage command value of the power conversion circuit output from the amplifier, and the corrected voltage commands Vd * and Vq * are exchanged. The second coordinate converter for calculating the three-phase system voltage value, the detected value of the voltage amplitude phase detector, the amplitude deviation of the voltage amplitude average value Vm and the phase average value Φm, and the phase deviations ΔVa to ΔVc, ΔΦa to ΔΦc Deviation calculation means for calculating and input amplitude and phase deviations ΔVa to ΔVc, ΔΦa to ΔΦc, and have first operation threshold values Vth1 and Φth1 for the amplitudes and phase deviations ΔVa to ΔVc, ΔΦa to ΔΦc. An overcurrent suppression dead band suppressor that suppresses overcurrent output from the power conversion circuit, and an overvoltage suppression dead band suppressor that has second operation threshold values Vth2 and Φth2 for deviation and suppresses the overvoltage output from the power conversion circuit. In the overvoltage suppression control method based on the reverse phase control provided, Vth1> Vth2 is set, and the overcurrent suppression dead zone device has any one of the amplitude, the phase deviations ΔVa to ΔVc, and ΔΦa to ΔΦc as the first operation threshold value Vth1. , Φth1 is exceeded, the overcurrent suppression dead band output values ΔVa to ΔVc and ΔΦa to ΔΦc of the same value as the deviation are output, and the overvoltage suppression dead band is any one of amplitude and phase deviation ΔVa to ΔVc, ΔΦa to ΔΦc Output overvoltage suppression dead band output values ΔVva to ΔVvc and ΔΦva to ΔΦvc when the second operating threshold value Vth2 and Φth2 are exceeded. The deviations ΔVva to ΔVvc in the pressure suppression dead band output value are subtracted from the deviations ΔVa to ΔVc in the over current suppression dead band output, respectively, to obtain correction voltage deviations ΔVd to ΔVf, and further the overvoltage suppression dead band output value Deviations ΔΦva to ΔΦvc are subtracted from the deviations ΔΦa to ΔΦc of the overcurrent suppression dead zone output values to obtain corrected phase deviations ΔΦd to ΔΦf, which are calculated into sine wave signals, and the sine wave signals and corrections The voltage deviations ΔVd to ΔVf are calculated by the multiplier and the voltage command correction values ΔVa * to ΔVc * of the operation output are added to the output of the second coordinate converter by the adder to obtain the voltage command value of the power conversion circuit. Since the power conversion circuit is controlled via the pulse width modulator that inputs the voltage command value, it is possible to control the power system voltage imbalance that occurs in the event of an accident, etc. It is possible to suppress the overcurrent against a high AC overvoltage while suppressing the overcurrent with a high-speed response.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to the drawings.
FIG. 1 is a configuration diagram illustrating a power conversion device 200 according to an overvoltage suppression control method based on reverse phase control according to the first embodiment. In FIG. 1, the AC side of the power conversion circuit 1 is connected to a power system 4 via a reactor 2, and the DC side is connected to a capacitor 3. The voltage of the power system 4 is detected by the AC voltage detector 6, and the phase θ is detected by the phase detector 7. The current flowing from the power conversion circuit 1 to the power system 4 is detected by the AC current detector 5 and converted by the current component detector 101 into a rotating coordinate system with the phase θ as a reference, and the effective current component Id and the reactive current component. Iq is detected.
The respective current components Id and Iq are calculated with respect to their command values Id * and Iq * by the subtracters 102a and 102b, and are amplified by the amplifiers 103a and 103b.

The adders 109 a and 109 b add the phase θ detected by the phase detector 7 and the fixed values Φv and Φw corresponding to the phase difference between the three-phase voltages of the power system 4. The voltage amplitude phase detectors 108a to 108c detect the voltage amplitudes Va to Vc and the phases Φa to Φc from the voltages of the respective phases detected by the AC voltage detector 6 and the output values of the adders 109a and 109b. The voltage amplitude adder 110a adds the voltage amplitudes Va to Vc, and the gain 111a for inputting the value calculates the average value Vm of the three-phase voltage amplitudes of the power system 4.
The phase adder 110b adds the phases [Phi] a to [Phi] c, and the gain 111b for inputting the values calculates the phase average value [Phi] m. Then, the first coordinate converter 114 converts the voltage amplitude average value Vm and the phase average value Φm from polar coordinates to orthogonal coordinates, and calculates average voltage components Vdm and Vqm.

The adders 104a and 104b add the signals obtained by amplifying the current deviation by the amplifiers 103a and 103b and the average voltage components Vdm and Vqm to obtain voltage commands Vd * and Vq *, and input the second coordinates. The converter 105 converts the orthogonal coordinates into three-phase coordinates.
The subtractors 112a to 112c calculate voltage difference amplitude deviations ΔVa to ΔVc from the voltage amplitudes Va to Vc and the voltage amplitude average value Vm. The subtractors 113a to 113c calculate phase deviations ΔΦa to ΔΦc from the phases Φa to Φc and the phase average value Φm. The overcurrent suppression dead band unit 115 receives the ΔVa to ΔVc and ΔΦa to ΔΦc, and outputs overcurrent suppression dead band output values ΔVa to ΔVc and ΔΦa to ΔΦc as calculation results. Further, the calculated output values ΔVa to ΔVc and ΔΦa to ΔΦc of the subtractors 112a to 112c and 113a to 113c are also input to the overvoltage suppression dead zone device 116, and the overvoltage suppression dead zone output values ΔVva to ΔVvc and ΔΦva to ΔΦvc are calculated as the calculation results. Is output.

The subtractors 117a to 117c input and calculate the output values ΔVa to ΔVc of the overcurrent suppression dead zone 115 and the output values ΔVva to ΔVvc of the overvoltage suppression dead zone 116, and output corrected voltage deviations ΔVd to ΔVf.
Further, the subtractors 117d to 117f receive and calculate the output values ΔΦa to ΔΦc of the overcurrent suppression dead zone 115 and the output values ΔΦva to ΔΦvc of the overvoltage suppression dead zone 116, and correct phase deviations ΔΦd to ΔΦf is output. The sine wave device 118 receives the phase θ detected by the phase detector 7 and the corrected phase deviations ΔΦd to ΔΦf and calculates them into a sine wave signal. The multipliers 119a to 119c receive the calculation output of the sine wave generator 118 and the correction voltage deviations ΔVd to ΔVf, and output the voltage command correction values ΔVa * to ΔVc * as a result.

  The adders 106a to 106c input and calculate the output of the second coordinate converter 105 and the voltage command correction values ΔVa * to ΔVc *, and output voltage command values Va * to Vc *. The pulse width modulator 107 receives the voltage command values Va * to Vc * and outputs an ON / OFF signal of a semiconductor element in the power conversion circuit 1.

Next, the operation will be described.
The alternating current detector 5 detects the alternating current output from the power conversion circuit 1, and the current component detector 101 divides the alternating current into an effective current component Id and a reactive current component Iq. Since the current component detector 101 is based on the phase of the power system 4, the phase detector 7 that detects the phase synchronized with the reference phase of the power system voltage detected by the AC voltage detector 6, for example, the a phase, is output. The phase θ to be used is used.
The subtractors 102a and 102b receive the effective current component Id and the reactive current component Iq, respectively, calculate the deviation between the active current command value Id * and the reactive current command value Iq *, and calculate the respective deviations by the amplifier 103a. , 103b. The amplifiers 103a and 103b input and amplify the deviation to generate a voltage command value for the power conversion circuit 1, perform feedback control as a current control system, and the current output from the power conversion device 200 matches the command value. To work.
The adders 104a and 104b add and calculate the output of the amplifiers 103a and 103b and the average voltage components Vdm and Vqm, which are average values of the dq components of the AC three-phase voltage of the power system 4, and calculate the voltage commands Vd * and Vq. * Is output. The second coordinate converter 105 calculates the voltage commands Vd * and Vq * from the dq coordinate system to an AC three-phase system. The voltage command correction values ΔVa * to ΔVc * output from the multipliers 119a to 119c, which will be described in detail later, and the output of the second coordinate converter 105 are added and calculated by the adders 106a to 106c to obtain the voltage command values Va * to Vc. * Is output. The pulse width modulator 107 generates a gate pulse so that a voltage corresponding to the voltage command values Va * to Vc * is output from the power conversion circuit 1, and supplies the gate pulse to the semiconductor element of the power conversion circuit 1. The power conversion circuit 1 performs switching according to the gate pulse, and outputs a voltage corresponding to the voltage command values Va * to Vc * to the power system 4 side.

The process until the voltage command correction values ΔVa * to ΔVc * are output by the multipliers 119a to 119c will be described in detail below.
The voltage amplitude phase detectors 108a to 108c determine the power system voltage of each phase from the voltage of the power system 4 of each phase detected by the voltage detector 6 and the reference phase θ of the AC voltage output from the phase detector 7. Amplitudes Va to Vc and phases Φa to Φc are detected, respectively. The voltage amplitude adder 110a adds the power system voltage amplitudes Va to Vc of each phase, and the addition result is multiplied by 1/3 by the gain 111a, so that the average value Vm of the power system voltage amplitude of each phase is obtained. Calculated. Similarly, the power system voltage phases Φa to Φc of each phase are added by the phase adder 110b, and the addition result is multiplied by 1/3 by the gain 111b, so that the average value Φm of the power system phase of each phase is obtained. Calculated. The first coordinate converter 114 converts the polar coordinates of Vm and Φm to the dq axis coordinates Vdm and Vqm.
Further, voltage difference amplitude deviations ΔVa to ΔVc are calculated from the power system voltage amplitudes Va to Vc of the respective phases and the average value Vm of the power system voltage amplitudes by the subtractors 112a to 112c. Similarly, phase deviations ΔΦa to ΔΦc are calculated from the power system voltage phases Φa to Φc of the respective phases and the average value Φm of the power system phases by the subtractors 113a to 113c.

  The first operation threshold values Vth1 and Φth1 for the amplitude deviations ΔVa to ΔVc and the phase deviations ΔΦa to ΔΦc are set in the overcurrent suppression dead band 115. When any one of the deviations exceeds the first operation threshold values Vth1 and Φth1, the overcurrent suppression dead zone device 115 sets the overcurrent suppression dead zone output values ΔVa to ΔVc and ΔΦa to ΔΦc equal to the input values, respectively. Output. When none of the deviations exceeds the first operation threshold values Vth1 and Φth1, the overcurrent suppression dead band device 115 outputs all zeros. When any of the deviations exceeds the first operating threshold values Vth1 and Φth1, the overcurrent suppression dead band output values ΔVa to ΔVc are respectively input to the subtractors 117a to 117c, and the subtractor 117d. .DELTA..PHI.a to .DELTA..PHI.c are input to .about.117f.

The second operation threshold values Vth2 and Φth2 for the amplitude deviations ΔVa to ΔVc and the phase deviations ΔΦa to ΔΦc are set in the overvoltage suppression dead zone 116, respectively. Here, the first operation threshold value Vth1> the second operation threshold value Vth2 is set. When any one of the deviations exceeds the second operation threshold values Vth2 and Φth2, the overvoltage suppression dead zone device 116 outputs ΔVva to ΔVvc and ΔΦva to ΔΦvc, which are overvoltage suppression dead zone output values, respectively.
When none of the deviations exceeds the second operation threshold values Vth2 and Φth2, the overvoltage suppression dead band device 116 outputs all zeros. When any of the deviations exceeds the second operation threshold values Vth2 and Φth2, ΔVva to ΔVvc and ΔΦva to ΔΦvc are input to the subtractors 117a to 117f. The subcurrentrs 117a to 117c are inputted with the overcurrent suppression dead zone output values ΔVa to ΔVc, and ΔVa to ΔVc and ΔVva to ΔVvc are calculated to output correction voltage deviations ΔVd to ΔVf. Further, the overcurrent suppression dead zone output values ΔΦa to ΔΦc are inputted to the subtractors 117d to 117f, and ΔΦa to ΔΦc and ΔΦva to ΔΦvc are calculated to output corrected phase deviations ΔΦd to ΔΦf.
Here, the importance of installing the overvoltage suppression dead band 116 will be described.
In the case of the configuration with only the overcurrent suppression dead band 115, the overcurrent output from the power conversion circuit 1 can be suppressed when the multiphase AC voltage of the power system becomes unbalanced. There is a possibility that an overvoltage occurs and the power conversion device 200 stops. However, in the present embodiment, an overvoltage suppression dead zone 116 is provided, and an overvoltage suppression dead zone 116 is provided and an overcurrent suppression dead zone 115 is provided in order to suppress the system voltage generated due to the overcurrent suppression. Since the second operation threshold value Vth2 is smaller than the first operation threshold value Vth1, it is possible to prevent the case where the power conversion apparatus 200 stops as described above.

The sine wave device 118 receives the corrected phase deviations ΔΦd to ΔΦf and the phase θ detected by the phase detector 7 and calculates a sine wave signal. The multipliers 119a to 119c receive the correction voltage deviations ΔVd to ΔVf and the output signal of the sine wave device 118, and the following expression ΔVa * = ΔVd × sin (θ + ΔΦd)
ΔVb * = ΔVe × sin (θ + ΔΦe)
ΔVc * = ΔVf × sin (θ + ΔΦf)
To calculate voltage command correction values ΔVa *, ΔVb *, ΔVc *.

  As described above, the adders 106a to 106c input the voltage command correction values ΔVa *, ΔVb *, ΔVc * and the output of the second coordinate converter 105, and calculate the voltage command values Va * to Vc *. The pulse width modulator 107 receives the voltage command values Va * to Vc * and controls the power conversion circuit 1 with a gate pulse signal.

  In the overvoltage suppression control method based on the reverse phase control provided with the power conversion device 200 according to the first embodiment, when an overvoltage including an unbalanced component occurs in the power system 4, the overvoltage has the highest amplitude due to the unbalance. When an unbalance occurs in the phase, but when any of ΔVa to ΔVc and ΔΦa to ΔΦc exceeds the first operating threshold Vth1 and Φth1 provided in the overcurrent suppression dead zone 115, power conversion When the overcurrent of the apparatus 200 is suppressed and the first operation threshold value Vth1> the second operation threshold value Vth2, and the second operation threshold values Vth2 and Φth2 are exceeded, ΔVva to ΔVvc The voltage command values Va * to Vc * are corrected by ΔΦva to ΔΦvc, and the AC voltage of the power conversion circuit 1 can be output so as to suppress the voltage imbalance of the power system 4. Therefore, if the voltage imbalance of the electric power system 4 is suppressed, the voltage amplitude of the phase that becomes an overvoltage can be suppressed, so that the overvoltage can be suppressed. Furthermore, by adjusting the first operation threshold Vth1, Φth1 of the overcurrent suppression dead band 115 and the second operation threshold Vth2, Φth2 of the overvoltage suppression dead band 116, according to the state of the power system, The overvoltage of the electric power grid | system 4 can be suppressed, suppressing the overcurrent of the power converter device 200. FIG.

Embodiment 2. FIG.
FIG. 2 is a configuration diagram showing a power conversion device 200 according to an overvoltage suppression control method based on reverse phase control according to Embodiment 2 of the present invention. Description of the same parts as those in FIG. 1 is omitted.
Gain elements 120a to 120c are provided at the output terminals of the overvoltage suppression dead zone 116, and outputs obtained by multiplying the output values ΔVva to ΔVvc by the gains 120a to 120c are input to the subtractors 117a to 117c.

  Next, the operation will be described. The description of the same operation as in FIG. 1 is omitted. Of the overvoltage suppression dead band 116 output, ΔVva to ΔVvc are amplified by gains 120a to 120c to change the degree of correction of the amplitude of the voltage correction signal.

  By operating in this way and adjusting the values of the gains 120a to 120c, the degree of suppression of voltage imbalance can be adjusted. Therefore, it is possible to suppress the overvoltage of the AC system while suppressing the overcurrent of the power conversion device 200 while adjusting the degree of suppression of the overvoltage of the power system.

Embodiment 3 FIG.
FIG. 3 is a configuration diagram showing a power conversion device 200 according to an overvoltage suppression control method based on reverse phase control according to Embodiment 3 of the present invention. Description of the same parts as those in FIGS. 1 and 2 is omitted.
The gains 120a to 120c of the second embodiment are provided with limiters and output to the subtracters 117a to 117c.

Next, the operation will be described. The description of the same operation as in FIGS. 1 and 2 is omitted.
By limiting the gains 120a to 120c, the degree of correction of the amplitude of the voltage correction signal for correcting the voltage imbalance is limited.

  By operating in this way and limiting the output of the gains 120a to 120c, the overcurrent of the power conversion device 200 is suppressed within the capacity range of the power conversion device 200 while suppressing the overcurrent of the power conversion device 200 as a main operation. Thus, the overvoltage suppression amount can be limited.

  The present invention can be used for a control method of a power converter that suppresses system overvoltage connected to the power system.

It is a block diagram which shows the power converter device of Embodiment 1 of this invention. It is a block diagram which shows the power converter device of Embodiment 2 of this invention. It is a block diagram which shows the power converter device of Embodiment 3 of this invention.

Explanation of symbols

1 power conversion circuit, 4 power system, 5 AC current detector, 6 AC voltage detector,
7 phase detector, 101 current component detector, 102a-102c subtractor,
103a to 103b amplifier, 104a to 104c adder,
105 second coordinate converter, 106a to 106c adder, 107 pulse width modulator,
108a-108c voltage amplitude phase detector, 112a-112c subtractor,
113a to 113c subtractor, 114 first coordinate converter,
115 Overcurrent suppression dead zone, 116 Overvoltage suppression dead zone,
117a to 117f subtractor, 118 sine wave device, 119a to 119c multiplier,
120a-120c gain, 121a-121c limiter, 200 power converter,
Id active current component, Iq reactive current component, Id * active current command value,
Iq * reactive current command value, Va to Vc voltage amplitude, Φa to Φc phase,
Vm Voltage system average value of power system, Φm Power system phase average value,
Vdm, Vqm Average voltage component, ΔVa to ΔVc amplitude deviation,
ΔΦa to ΔΦc phase deviation, ΔVva to ΔVvc overvoltage suppression dead band output value,
ΔΦva to ΔΦvc overvoltage suppression dead band output value, ΔVd to ΔVf correction voltage deviation,
ΔΦd to ΔΦf correction phase deviation, ΔVa * to ΔVc * voltage command correction value,
Va * to Vc * Voltage command value.

Claims (3)

A power conversion circuit that is connected to the power system, converts AC power and DC power in both directions, and controls pulse width modulation of the DC voltage, an AC voltage detector that detects the voltage of the power system, and the power conversion An AC current detector that detects a current flowing from the circuit to the power system, a phase detector that detects a reference phase from a detection value of the AC voltage detector, a detection value of the AC current detector, and a phase detector A current component detector that detects an active current component (Id) and a reactive current component (Iq) from the detected reference phase, an active current command value (Id *), the effective current component (Id), and a reactive current command An amplifier for amplifying the deviation between the value (Iq *) and the reactive current component (Iq) and using the output as a voltage command value for the power conversion circuit to feedback control the output AC current of the power conversion circuit; and the AC voltage detection A voltage amplitude phase detector that detects the voltage amplitude and phase of each phase from the detected value of the voltage detector, and the voltage amplitude average value (Vm) of the power system from the voltage amplitude and phase of each phase detected by this voltage amplitude phase detector ) And the phase average value (Φm), and the voltage amplitude average value (Vm) and the phase average value (Φm) are converted by the first coordinate converter to obtain the average voltage components (Vdm, Vqm). The average value calculating means for calculating and the output value of the average value calculating means are added to correct the voltage command value of the power conversion circuit output from the amplifier, and the corrected voltage commands (Vd *, Vq *) are obtained. A second coordinate converter for calculating an AC three-phase voltage value; a detected value of the voltage amplitude phase detector; an amplitude deviation and a phase deviation of the voltage amplitude average value (Vm) and phase average value (Φm) ( ΔVa to ΔVc, ΔΦa to ΔΦc) Means, and the amplitude and phase deviation (ΔVa to ΔVc, ΔΦa to ΔΦc) are input, and the first operating threshold value (Vth1, Φth1) for the amplitude and phase deviation (ΔVa to ΔVc, ΔΦa to ΔΦc) is input. An overcurrent suppression dead zone that suppresses an overcurrent output from the power conversion circuit, and a second operating threshold (Vth2, Φth2) for the deviation, and suppresses an overvoltage output from the power conversion circuit In the overvoltage suppression control system by reverse phase control with an overvoltage suppression dead band
The Vth1> Vth2 is set, and the overcurrent suppression dead band has any one of the amplitude and phase deviation (ΔVa to ΔVc, ΔΦa to ΔΦc) exceeding the first operating threshold (Vth1, Φth1). Output overcurrent suppression dead zone output values (ΔVa to ΔVc, ΔΦa to ΔΦc) that are equal to the deviation, and the overvoltage suppression dead zone device outputs the amplitude and phase deviation (ΔVa to ΔVc, ΔΦa to ΔΦc). When any of the above exceeds the second operation threshold value (Vth2, Φth2), an overvoltage suppression dead band output value (ΔVva to ΔVvc, ΔΦva to ΔΦvc) is output, and this overvoltage suppression dead band output The deviation (ΔVva to ΔVvc) in the value is subtracted from the deviation (ΔVa to ΔVc) in the output of the overcurrent suppression dead zone device to obtain a corrected voltage deviation (ΔVd to ΔVf), Deviations (ΔΦva to ΔΦvc) in the overvoltage suppression dead zone output values are subtracted from deviations (ΔΦa to ΔΦc) in the overcurrent suppression dead zone output values to obtain corrected phase deviations (ΔΦd to ΔΦf). A value is calculated into a sine wave signal, and the sine wave signal and the correction voltage deviation (ΔVd to ΔVf) are multiplied by a voltage command correction value (ΔVa * to ΔVc *) output by the multiplier and the second coordinate conversion is performed. The output of the converter is added by an adder to obtain a voltage command value for the power conversion circuit, and the power conversion circuit is controlled via a pulse width modulator that inputs the voltage command value. Overvoltage suppression control method. A gain element is provided at an output terminal of the overvoltage suppression dead zone device, and the amplitude deviation (ΔVva to ΔVvc) is multiplied by a gain to change the degree of correction of the amplitude deviation (ΔVva to ΔVvc). The overvoltage suppression control method by reverse phase control of 1. The overvoltage suppression control method by reverse phase control according to claim 2, wherein a limiter is provided in the gain element.

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