JP2006094684A - Controller of power converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller of a power converter in which unnecessary variation in effective power and reactive power of AC output power can be suppressed even if the input/output voltage of the power converter is varied due to fluctuation in system voltage. <P>SOLUTION: The controller of a power converter comprises power control means 15 and 16 for operating an effective power command value and a reactive power command value such that the effective power and reactive power of AC output voltage approach an effective power set value and a reactive power set value, respectively, a means 19 for receiving each power command value and operating each limiter value for limiting each power command value such that the apparent power does not exceed the power capacity of the power converter, means 24 and 25 for removing a variation component superposed on each limiter value, means 17 and 18 for limiting each power command value by using each limiter value from which a variation component is removed, and a means 22 for generating a gate signal being applied to the power converter based on each power command value limited by the limiter means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a control device for a self-excited power converter that converts power from alternating current to direct current or from direct current to alternating current.

  For example, when power is supplied from one AC power system to an AC power system having different frequencies, a frequency converter is installed between the AC power systems. Such a power system in which an AC power system and a frequency converter are incorporated is configured as shown in FIG.

  AC power supplied from one AC power system 1 is input via a transformer 2 to a rectifier 3 that employs PWM control as a power conversion device, converted into DC power by the rectifier 3, a capacitor 4, 6 is input to an inverter (inverse converter) 7 that employs PWM control as a power converter via a DC reactor 5. The inverter (inverse converter) 7 converts the input DC power into AC power having a frequency different from that of the AC power system 1 and outputs the AC power to the other AC power system 9 via the transformer 8.

  Here, the rectifier 3 and the inverter (inverse converter) 7 as the power conversion device have basically the same configuration. For example, a self-extinguishing power semiconductor switching element such as an IEGT, IGBT, transistor, or GTO is used. It has a bridge-connected configuration. Each power semiconductor switching element is subjected to switching control (PWM control) with each gate pulse signal, thereby converting power from AC to DC or from DC to AC.

  The control device 10 that controls the operation of the inverter (inverse converter) 7 as the power conversion device having such a configuration detects the output voltage of the inverter (inverse converter) 7 by each transformer 11, and the inverter (inverse conversion). The output current of the generator 7 is detected by each current transformer 12, a gate pulse signal is created based on the output voltage and output current, and is applied to the inverter (inverse converter) 7.

  Note that a substantially similar control device (not shown) is provided for the rectifier 3 as the other power conversion device.

  FIG. 5 is a block diagram showing a schematic configuration of the control device 10. The output voltage V detected by each transformer 11 and the output current I detected by each current transformer 12 are input to the converter output calculation unit 13 in the control device 10. The converter output calculation unit 13 uses the detected output voltage V and output current I, and the active power P (= VIcos θ) and reactive power Q (=) of the AC power output from the inverter (inverse converter) 7. VIsinθ) is calculated (detected). Here, θ is a phase difference between the output voltage V and the output current I. The converter output calculation unit 13 sends the detected active power P and reactive power Q to the active power control unit (APR) 15 and the reactive power control unit (AQR) 16, respectively.

The power setting unit 14 sets the active power set value P _S and the reactive power set value Q _S as targets of AC power output from the inverter (inverter) 7 preset by the administrator of the power system. Each is sent to the active power control unit (APR) 15 and the reactive power control unit (AQR) 16. Active power controller (APR) 15, as active power P detected approaches the active power set value P _S, PI (proportional integral) control calculation to give a active power command value C _P performed, the effective It sends a power command value C _P to the next of the limiter portion 17 and the limiter value calculating unit 19. Reactive power controller (AQR) 16, as reactive power Q detected is closer to the reactive power setpoint Q _S, PI (proportional integral) control calculation to give a reactive power command value C _Q go, this invalid It sends a power command value C _Q next limiter 18 and the limiter value calculating unit 19.

The limiter value calculation unit 19 uses the power capacity MVA (apparent power) of the inverter (inverse converter) 7, the active power command value C _P , and the reactive power command value C _Q as a power conversion device. value C _P, the limiter value for controlling an upper limit value and the lower limit respectively of the reactive power command value C _Q L _P, calculates the L _Q. The limiter value calculation unit 19 sets the calculated limiter values L _P and L _Q to the corresponding limiter units 17 and 18, respectively.

Limiter portion 17, the upper limit value and the lower limit value of the effective power command value C _P input limit by the limiter value L _P, and sends it to the arithmetic unit 20 as a new active power command value D _P. Similarly, the limiter portion 18, the upper limit value and the lower limit value of the reactive power command value C _Q input and limited by the limiter value L _Q, and sends it to the arithmetic unit 20 as a new active power command value D _Q.

Arithmetic unit that operate in the PLL circuit 21 is operated and the synchronous control of the transducer output computing unit 13 20, the input and active power command value D _P and the effective power command value D _Q, for example, a three-phase It is converted into a control value Ec based on the instantaneous value and sent to the next pulse generation circuit 22.

The pulse generation circuit 22 generates a gate pulse signal to be applied to the inverter 7 as a power converter based on the power command values D _P and D _Q converted into the control amount Ec based on the three-phase instantaneous value. In this case, the pulse generation circuit 22 generates a gate pulse signal for performing PWM control reflecting the output reference signal, and receives a signal from the carrier generation circuit 23 as a carrier wave for that purpose.

The gate pulse signal output from the pulse generation circuit 22 is applied to an inverter (inverse converter) 7 and used for switching of the semiconductor switching element of the inverter 7. As a result, the active power and reactive power of the AC power output from the inverter (inverse converter) 7 to the AC power system 9 side become the set values P _S and Q _S set by the power setting unit 14.

Next, the need to control the active power command value C _P, the upper limit value and the lower limit value of the reactive power command value C _Q, respectively.

In general, in the self-excited power converter of the rectifier 3 and the inverter 7, the active power P and the reactive power Q of the input / output AC power can be freely set within the range of the power capacity MVA (apparent power) of the power converter. it can. However, the apparent power of the set values P _S and Q _S set by the power setting unit 14 mainly by the human system is not always within the power capacity MVA (apparent power) of the power converter (inverter 7). Absent. Therefore, when the power command values C _P and C _Q exceed the power capacity MVA of the power converter (inverter 7), the upper limit value and the lower limit value of the power command values C _P and C _Q are set in the control device 10. Each must be restricted.

In addition, there is a method of limiting each power setting value P _S and Q _S itself set by the power setting unit 14, but in this method, depending on the calculation results of the active power control unit 15 and the reactive power control unit 16, the power conversion device Since the power capacity MVA of the (inverter 7) may be exceeded, limiters 17 and 18 are provided at the final stage as shown in FIG. 5 and the limiter value calculator 19 sets the limiters 17 and 18 respectively. The respective limiter values L _P and L _Q to be calculated are calculated.

Examples include circular limiter is used to adjust the active power command value C _P, reactive power command value C _Q.

  In the actual operation of the power conversion device (inverter 7), the power conversion device (inverter 7) is prioritized such as (a) giving priority to accommodation of active power or (b) giving priority to reactive power in order to give priority to voltage maintenance of the system. ), It is necessary to give priority to one of the set values, so a limiter value with priority is often set.

(A) When prioritizing active power L _P = MVA L _Q = [MVA ² −C _P ² ] ^1/2 (1)
(B) When giving priority to reactive power L _P = [MVA ² −C _Q ² ] ^1/2 L _Q = MVA (2)
In the control of a self-excited power converter, a technique for limiting the active power command value and the reactive power command value using a limiter is described in Patent Document 1.
JP-A-5-168148

  However, the power converter control device shown in FIG. 5 still has the following problems to be improved.

That is, as can be understood from the equations (1) and (2), the limiter value of the low priority power is affected by the fluctuation of the high priority power. When the set values P _S and Q _S set by the power setting unit 14 are set in the vicinity of the power capacity MVA of the power converter, the power command values C _P and C _Q are the limiter values L _P , in L _Q near, the power converter is operated.

As a result, for example, the output voltage of the power conversion device fluctuates due to load fluctuations in the power system, and the detected powers P and Q fluctuate due to this fluctuation, and power command values C _P and C _Q When the limiter values L _P and L _Q fluctuate, the low-priority power fluctuates in the same manner as the limiter values L _P and L _Q fluctuate. The same applies to the circle limiter.

The same phenomenon occurs when the power setting values P _S and Q _{S of} the power setting unit 14 fluctuate.

  The present invention has been made in view of such circumstances. For example, the output voltage of the power converter varies or the power setting values for the power converter vary due to load fluctuations in the power system. Even if the active power and reactive power of the AC power input / output to / from the power converter are kept within the power capacity of the power converter, the power converter control device can suppress unnecessary fluctuations. The purpose is to provide.

  In order to solve the above problems, the present invention provides a control device for a self-excited power conversion device that converts power from alternating current to direct current or from direct current to alternating current. Power detection means for detecting power, power setting means for setting active power setting values and reactive power setting values of AC power input or output to the power converter, and detected active power and reactive power are each valid Power control means for calculating the active power command value and the reactive power command value so as to be close to the power setting value and the reactive power setting value, and input the power command values so that the apparent power does not exceed the power capacity of the power converter. Limiter value calculation means for calculating each limiter value for limiting each power command value, and removal for removing fluctuation components superimposed on each limiter value output from the limiter value calculation means And limiter means for limiting each power command value using each limiter value from which the fluctuation component has been removed by the removing means, and application to the power converter based on each power command value whose value is limited by this limiter means Gate signal generation means for generating a gate signal to be generated.

  In the control device of the power conversion device configured as described above, a removing unit that removes the fluctuation component superimposed on each limiter value output from the limiter value calculating unit is provided. This removing means is composed of, for example, an off-delay type timer, and follows a direction in which the absolute value of each limiter value output from the limiter value calculating means increases with a certain delay time. In addition, it has a function of instantaneously following the direction in which the absolute value of each limiter value output from the limiter value calculation means decreases. Therefore, the limiter value actually set in the limiter means does not fluctuate at least in the increasing direction.

  Therefore, even if the output voltage of the power conversion device fluctuates due to load fluctuations in the power system, or each power setting value for the power conversion device fluctuates, each limiter value output from the limiter value calculation means is short. Even if it fluctuates with time, the fluctuation of each limiter value is absorbed by the delay means, and the limiter value actually set in the limiter means does not fluctuate. As a result, it is possible to prevent the output power values of the active power and the reactive power from changing unnecessarily and adversely affecting the operation of the power converter.

  Another invention is a control device for a self-excited power conversion device that converts power from alternating current to direct current or from direct current to alternating current, and detects active power and reactive power of alternating current power that is input to or output from the power conversion device. Power detection means, power setting means for setting active power set value and reactive power set value of AC power input or output to the power converter, and active power command value so that the active power is close to the active power set value Active power control means for calculating the reactive power, the reactive power control means for calculating the reactive power command value so that the reactive power is close to the reactive power setting value, and the active power command value is limited using the set limiter value. The power command value limiter means, the reactive power command value limiter means for limiting the reactive power command value using the set limiter value, and the active power whose value is limited by the active power command value limiter means Input the command value, give priority to the active power command value, and calculate each limiter value to be set to each limiter means for limiting each power command value so that the apparent power does not exceed the power capacity of the power converter Based on the limiter value calculation means, the removal means for removing the fluctuation component superimposed on the limiter value set from the limiter value calculation means to the reactive power command value limiter means, and each power command value whose value is limited by each limiter means And a gate signal generating means for generating a gate signal to be applied to the power converter.

  Further, the limiter value calculation means sets the limiter value for the active power command value limiter means to the power capacity of the power converter, and sets the limiter value for the reactive power command value limiter means to the square of the power capacity of the power converter. It is set to the square root of the value obtained by subtracting the square value of the active power command value in which the value is limited from the value.

  In the control device of the power conversion device configured as described above, the active power fluctuation affects the reactive power command value, that is, the reactive power output, while giving priority to the active power command value. Can be prevented from adversely affecting.

  Another invention is a control device for a self-excited power conversion device that converts power from alternating current to direct current or from direct current to alternating current, and detects active power and reactive power of alternating current power that is input to or output from the power conversion device. Power detection means, power setting means for setting active power set value and reactive power set value of AC power input or output to the power converter, and active power command value so that the active power is close to the active power set value Active power control means for calculating the reactive power, the reactive power control means for calculating the reactive power command value so that the reactive power is close to the reactive power setting value, and the active power command value is limited using the set limiter value. Power command value limiter means, reactive power command value limiter means for limiting the reactive power command value using the set limiter value, and reactive power whose value is limited by the reactive power command value limiter means Input the command value, give priority to the reactive power command value, and calculate each limiter value to be set to each limiter means for limiting each power command value so that the apparent power does not exceed the power capacity of the power converter Based on the limiter value calculating means, the removing means for removing the fluctuation component superimposed on the limiter value set to the active power command value limiter means from the limiter value calculating means, and each power command value whose value is limited by each limiter means And a gate signal generating means for generating a gate signal to be applied to the power converter.

  Further, the limiter value calculating means sets the limiter value for the reactive power command value limiter means to the power capacity of the power converter, and the limiter value for the active power command value limiter means is calculated from the square value of the power capacity of the power converter. The value is set to the square root of the value obtained by subtracting the square value of the reactive power command value that is limited.

  In the control device for the power conversion device configured as described above, the reactive power fluctuation causes an unnecessary fluctuation in the active power command value, that is, the active power output while giving priority to the reactive power command value, and the operation of the power conversion device is performed. Can be prevented from adversely affecting.

  In the present invention, there is provided removal means for removing the fluctuation component superimposed on each limiter value output from the limiter value calculation means toward the limiter means.

  Therefore, even if the output voltage of the power conversion device fluctuates due to load fluctuations in the power system, or each power setting value for the power conversion device fluctuates, each limiter value output from the limiter value calculation means is short. Even if it fluctuates over time, the active power and reactive power of AC power input and output to and from this power converter can be kept within the power capacity of this power converter, while suppressing unnecessary fluctuations. Can be adversely affected.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing a schematic configuration of a control device for a power conversion device according to the first embodiment of the present invention. The same parts as those of the control device 10 of the conventional power converter shown in FIG. Further, the configuration of an inverter (inverse converter) 7 as a power conversion device to be controlled by the control device 10a of the first embodiment and a power system including the inverter (inverse converter) 7 are shown in FIG. Since this is the same as the configuration of the power system, the description is omitted.

In the control device 10a according to the first embodiment, the converter output calculation unit 13 uses the detected output voltage V and output current I, and the active power P of the AC power output from the inverter (inverse converter) 7. The reactive power Q is calculated and sent to the active power control unit (APR) 15 and the reactive power control unit (AQR) 16. The power setting unit 14 sends the active power set value P _S and the reactive power set value Q _S to the active power control unit (APR) 15 and the reactive power control unit (AQR) 16, respectively.

Active power controller (APR) 15 calculates the active power command value C _P so that the effective power P detected approaches the active power set value P _S, the next limiter portion 17 and the limiter-value calculation section 19 Send it out. Reactive power controller (AQR) 16 calculates the reactive power command value C _Q as reactive power Q detected is closer to the reactive power setpoint Q _S, the next limiter 18 and the limiter-value calculation section 19 Send it out.

The limiter value calculation unit 19 uses the power capacity MVA (apparent power) of the inverter (inverse converter) 7, the active power command value C _P , and the reactive power command value C _Q as a power conversion device. value C _P, the upper limit value and the lower limit value of the reactive power command value C _Q described above shown by the following formula for controlling respectively (a), calculates the (b) 2 kinds of the limit value L _P, L _Q.

(A) When prioritizing active power L _P = MVA L _Q = [MVA ² −C _P ² ] ^1/2 (1)
(B) When giving priority to reactive power L _P = [MVA ² −C _Q ² ] ^1/2 L _Q = MVA (2)
The limiter value calculation unit 19 sends the calculated limiter values L _P and L _Q to delay elements 24 and 25 as delay means, respectively. Each of the delay elements 24 and 25 is composed of, for example, an off-delay type timer, and is constant in the direction in which the absolute values of the limiter values L _P and L _Q output from the limiter value calculation unit 19 increase. And has a function of instantaneously following the direction in which the absolute values of the limiter values L _P and L _Q output from the limiter value calculation unit 19 become smaller. Therefore, short-time fluctuation components in the limiter values L _P and L _Q output from the limiter value calculator 19 are removed by the delay elements 24 and 25. The limiter values L _P and L _{Q that} have passed through the delay elements 24 and 25 do not fluctuate at least in the increasing direction.

The limiter values L _P and L _Q via the delay elements 24 and 25 are set in the corresponding limiter units 17 and 18, respectively.

Limiter portion 17 limits in via the delay element 24 the upper limit value and the lower limit value of the effective power command value C _P input limit value L _P, and sends it to the arithmetic unit 20 as a new active power command value D _P . Similarly, the limiter 18 is limited by via the delay element 25 the upper limit value and the lower limit value of the reactive power command value C _Q input limiter value L _Q, the arithmetic unit 20 as a new reactive power command value D _Q To send.

Calculation unit 20, the input and active power command value D _P and the reactive power command value D _Q, for example by converting the instantaneous value based control amount Ec of the three-phase, and sends to the next pulse generation circuit 22. The pulse generation circuit 22 generates a gate pulse signal to be applied to the inverter 7 as a power converter based on the power command values D _P and D _Q converted into the control amount Ec based on the three-phase instantaneous value.

The gate pulse signal output from the pulse generation circuit 22 is applied to an inverter (inverse converter) 7 and used for switching of the semiconductor switching element of the inverter 7. As a result, the active power and reactive power of the AC power output from the inverter (inverse converter) 7 to the AC power system 9 side become the set values P _S and Q _S set by the power setting unit 14.

In the control device 10a of the power conversion device of the first embodiment configured as described above, the output voltage of the power conversion device (inverter 7) fluctuates due to load fluctuation of the power system, or the power conversion device (inverter) 7) The power set values P _S and Q _S with respect to 7) fluctuate, the active power command value C _P and the reactive power command value C _Q fluctuate, and finally each limiter value output from the limiter value calculation unit 19 Even if L _P and L _Q fluctuate in a short time, this short fluctuation is absorbed by the delay elements 24 and 25, and the limiter values L _P and L _Q actually set in the limiter units 17 and 18 fluctuate. do not do.

As a result, the active power command value D _P and the reactive power command value D _Q to be inputted to the arithmetic unit 20 does not include variation component. Therefore, it is possible to prevent the output power values of the active power and the reactive power from changing unnecessarily and adversely affecting the operation of the power converter (inverter 7).

(Second Embodiment)
FIG. 2 is a block diagram showing a schematic configuration of a control device of the power conversion device according to the second embodiment of the present invention. The same parts as those in the control device 10a of the power conversion apparatus according to the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and detailed description of the overlapping parts is omitted. Further, the configuration of an inverter (inverse converter) 7 as a power conversion device to be controlled by the control device 10b of the second embodiment and a power system including the inverter (inverse converter) 7 are shown in FIG. Since this is the same as the configuration of the power system, the description is omitted.

In this control device 10b of the power converter of the second embodiment, the active power controller (APR) 15 sends an active power command value C _P calculated to the limiter portion 17. The reactive power control unit (AQR) 16 sends the calculated reactive power command value _CQ to the limiter unit 18.

Further, the active power command value D _P sent from the limiter unit 17 to the calculation unit 20 is input to the limiter value calculation unit 19a. The limiter value calculating unit 19a includes an inverter (reverse converter) 7 power capacity MVA (apparent power) as a power converter, by using the active power command value D _P outputted from the limiter unit 17, the active power command value C _P, shown in (3) for limiting the upper and lower limit values, respectively of the reactive power command value C _Q, preferentially active power command value, apparent power is the power capacity of the power converter Each limiter value L _P and L _Q is calculated so as not to exceed.

L _P = MVA L _Q = [MVA ² −D _P ² ] ^1/2 (3)
The limiter value calculation unit 19a directly sets the calculated one limiter value L _P to the limiter unit 17 and sets the calculated other limiter value L _Q to the limiter unit 18 via the delay element 25 as a delay unit. To do.

Thus, the limiter value L _P set to the limiter unit 17 on the active power side is the power capacity MVA of the inverter (inverse converter) 7 and does not change. On the other hand, the limiter value L _Q is set to the reactive power side of the limiter unit 18, becomes the remaining capacity obtained by subtracting the effective power command value D _P min from the power capacity MVA inverter (reverse converter) 7. That is, the active power priority limiter values L _P and L _Q are obtained. Since the limiter value _LQ may fluctuate, the fluctuation component is removed by the delay element 25.

Limiter portion 17, the upper limit value and the lower limit value of the effective power command value C _P input limit by the limiter value L _P, and sends it to the arithmetic unit 20 as a new active power command value D _P. Limiter portion 18 limits in via the delay element 25 the upper limit value and the lower limit value of the reactive power command value C _Q input limiter value L _Q, and sends it to the arithmetic unit 20 as a new reactive power command value D _Q .

In the control device 10b of the power conversion device of the second embodiment configured as described above, the output voltage of the power conversion device (inverter 7) fluctuates due to load fluctuations in the power system, or the power conversion device (inverter) 7) The power set values P _S and Q _S with respect to 7) vary, the active power command value C _P and the reactive power command value C _Q vary, and the limiter value L _Q output from the limiter value calculation unit 19a also varies. . When there is no delay element 25, the output of reactive power is changed as it is. However, by the action of the delay element 25, the active power command value D _P increases, i.e. with respect to the direction in which the limiter value L _Q decreases, in response to the instantaneous inverter (inverter) 7 power capacity MVA Reduce the reactive power limiter so that

Moreover, the active power command value D _P conversely becomes small, that is with respect to the direction in which the limiter value L _Q increases by the action of delay element 25, responsive cheat order with a delay, reactive power output increases abruptly Never do.

In particular, when the active power command value C _P (D _P ) of the active power control unit 15 is vibrating, if there is no delay element 25, the vibration directly affects the output of reactive power. However, in order to continue the state where the limiter value L _Q is throttled by the delay element 25 avoiding unwanted vibration to the output of the reactive power.

  As described above, in the control device 10b of the power conversion device according to the second embodiment, even if the active power value output from the power conversion device (inverter 7) is fluctuated due to fluctuations in the system voltage and the set value, It is possible to suppress the reactive power output from being fluctuated unnecessarily due to the influence, and to prevent adverse effects on the interconnected power system.

(Third embodiment)
FIG. 3 is a block diagram showing a schematic configuration of the control device of the power conversion device according to the third embodiment of the present invention. The same parts as those in the control device 10a of the power conversion apparatus according to the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and detailed description of the overlapping parts is omitted. Further, the configuration of an inverter (inverse converter) 7 as a power conversion device to be controlled by the control device 10c of the third embodiment and a power system including the inverter (inverse converter) 7 are shown in FIG. Since this is the same as the configuration of the power system, the description is omitted.

In this control unit 10c of the power conversion device of the third embodiment, the active power controller (APR) 15 sends an active power command value C _P calculated to the limiter portion 17. The reactive power control unit (AQR) 16 sends the calculated reactive power command value _CQ to the limiter unit 18.

Further, the reactive power command value _DQ sent from the limiter unit 18 to the calculation unit 20 is input to the limiter value calculation unit 19b. The limiter value calculation unit 19b uses the power capacity MVA (apparent power) of the inverter (inverse converter) 7 as a power converter and the reactive power command value D _Q output from the limiter unit 18 to use this active power. command value C _P, indicated by (4) for the upper and lower limits for limiting each of the reactive power command value C _Q, preferentially reactive power command value, the power capacity MVA apparent power is the power converter Each limiter value L _P and L _Q is calculated so as not to exceed.

L _P = [MVA ² −D _Q ² ] ^1/2 L _Q = MVA (4)
The limiter value calculation unit 19b sets the calculated one limiter value L _P to the limiter unit 17 via the delay element 24 as a delay unit, and sets the calculated other limiter value L _Q directly to the limiter unit 18. To do.

Thus, the limiter value L _Q is set to the reactive power side limiter 18, an inverter (reverse converter) 7 power capacity MVA unchanged and in itself. On the other hand, the limiter value L _P set in the limiter unit 17 on the active power side is the remaining capacity obtained by subtracting the reactive power command value D _Q from the power capacity MVA of the inverter (inverse converter) 7. That is, the reactive power priority limiter values L _P and L _Q are obtained. Since the limiter value L _P may fluctuate, the fluctuation component is removed by the delay element 24.

Limiter portion 17 limits in via the delay element 24 the upper limit value and the lower limit value of the effective power command value C _P input limit value L _P, and sends it to the arithmetic unit 20 as a new active power command value D _P . Limiter portion 18, the upper limit value and the lower limit value of the reactive power command value C _Q input and limited by the limiter value L _Q, and sends it to the arithmetic unit 20 as a new reactive power command value D _Q.

In the control device 10c of the power conversion device of the third embodiment configured as described above, the output voltage of the power conversion device (inverter 7) fluctuates due to load fluctuations in the power system, or the power conversion device (inverter) 7) The power set values P _S and Q _S for fluctuate, the active power command value C _P and the reactive power command value C _Q fluctuate, and the limiter value L _P output from the limiter value calculator 19b also fluctuates. . When there is no delay element 24, the output of active power is changed as it is. However, due to the action of the delay element 24, the power capacity MVA of the inverter (inverse converter) 7 responds instantaneously to the direction in which the reactive power command value D _Q increases, that is, the limiter value L _P decreases. Limit the active power limiter so that

Conversely, the reactive power command value D _Q decreases, that is, the limiter value L _P increases, and the delay element 24 responds with a delay, so that the active power output increases rapidly. Never do.

In particular, when the reactive power command value C _Q (D _Q ) of the reactive power control unit 16 is vibrating, if there is no delay element 24, the vibration directly affects the output of the active power. However, since the state where the limiter value L _P is reduced by the delay element 24 is continued, unnecessary vibration is not given to the output of the active power.

  As described above, in the control device 10c of the power conversion device according to the third embodiment, even if the active power value output from the power conversion device (inverter 7) is fluctuated due to fluctuations in the system voltage and the set value, the It is possible to suppress the reactive power output from being fluctuated unnecessarily due to the influence, and to prevent adverse effects on the interconnected power system.

  The present invention is not limited to the above-described embodiments. In the embodiment, the inverter 7 is employed as the power conversion device to be controlled. However, the rectifier 3 can also be employed as the power conversion device to be controlled.

The block diagram which shows schematic structure of the control apparatus of the power converter device concerning 1st Embodiment of this invention. The block diagram which shows schematic structure of the control apparatus of the power converter device concerning 2nd Embodiment of this invention. The block diagram which shows schematic structure of the control apparatus of the power converter device concerning 3rd Embodiment of this invention. Schematic diagram showing a power system incorporating an AC power system and a frequency converter The block diagram which shows schematic structure of the control apparatus of the conventional power converter device

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,9 ... AC power system, 2,8 ... Transformer, 3 ... Rectifier, 7 ... Inverter 10, 10a, 10b, 10c ... Control apparatus, 11 ... Transformer, 12 ... Current transformer, 13 ... Converter output Calculation unit, 14 ... power setting unit, 15 ... active power control unit (APR), 16 ... reactive power control unit (AQR), 17, 18 ... limiter unit, 19, 19a, 19b ... limiter value calculation unit, 20 ... calculation , 21 ... PLL circuit, 22 ... pulse generation circuit, 23 ... carrier wave generation circuit, 24,25 ... delay element

Claims (5)

In a control device for a self-excited power converter that converts power from alternating current to direct current or direct current to alternating current,
Power detection means for detecting active power and reactive power of AC power input or output to the power converter;
Power setting means for setting an active power setting value and a reactive power setting value of AC power input or output to the power converter;
Power control means for calculating the active power command value and the reactive power command value so that the detected active power and reactive power are close to the active power setting value and the reactive power setting value, respectively;
Limiter value calculating means for inputting each power command value and calculating each limiter value for limiting each power command value so that the apparent power does not exceed the power capacity of the power converter,
Removing means for removing the fluctuation component superimposed on each limiter value output from the limiter value calculating means;
Limiter means for limiting each power command value using each limiter value from which the fluctuation component has been removed by the removing means;
A control apparatus for a power converter, comprising: a gate signal generator that generates a gate signal to be applied to the power converter based on each power command value whose value is limited by the limiter. In a control device for a self-excited power converter that converts power from alternating current to direct current or direct current to alternating current,
Power detection means for detecting active power and reactive power of AC power input or output to the power converter;
Power setting means for setting an active power setting value and a reactive power setting value of AC power input or output to the power converter;
Active power control means for calculating an active power command value so that the active power is close to an active power setting value;
Reactive power control means for calculating a reactive power command value so that the reactive power is close to a reactive power setting value;
Active power command value limiter means for limiting the active power command value using a set limiter value;
Reactive power command value limiter means for limiting the reactive power command value using a set limiter value;
Input the active power command value whose value is limited by the active power command value limiter, and prioritize the active power command value, so that the apparent power does not exceed the power capacity of the power converter. Limiter value calculating means for calculating each limiter value to be set to each limiter means for limiting
Removing means for removing the fluctuation component superimposed on the limiter value set to the reactive power command value limiter means from the limiter value calculation means;
A control device for a power converter, comprising: a gate signal generator that generates a gate signal to be applied to the power converter based on each power command value whose value is limited by each limiter.   The limiter value calculation means sets the limiter value for the active power command value limiter means to the power capacity of the power converter, and sets the limiter value for the reactive power command value limiter means as 2 of the power capacity of the power converter. 3. The control device for a power converter according to claim 2, wherein the control device is set to a square root of a value obtained by subtracting a square value of an active power command value whose value is limited from a multiplier value. In a control device for a self-excited power converter that converts power from alternating current to direct current or direct current to alternating current,
Power detection means for detecting active power and reactive power of AC power input or output to the power converter;
Power setting means for setting an active power setting value and a reactive power setting value of AC power input or output to the power converter;
Active power control means for calculating an active power command value so that the active power is close to an active power setting value;
Reactive power control means for calculating a reactive power command value so that the reactive power is close to a reactive power setting value;
Active power command value limiter means for limiting the active power command value using a set limiter value;
Reactive power command value limiter means for limiting the reactive power command value using a set limiter value;
Input the reactive power command value whose value is limited by the reactive power command value limiter means, giving priority to the reactive power command value, so that the apparent power does not exceed the power capacity of the power converter. Limiter value calculating means for calculating each limiter value to be set to each limiter means for limiting
Removing means for removing the fluctuation component superimposed on the limiter value set to the active power command value limiter means from the limiter value calculation means;
A control device for a power converter, comprising: a gate signal generator that generates a gate signal to be applied to the power converter based on each power command value whose value is limited by each limiter.   The limiter value calculation means sets the limiter value for the reactive power command value limiter means to the power capacity of the power converter, and sets the limiter value for the active power command value limiter means as 2 of the power capacity of the power converter. 5. The control device for a power converter according to claim 4, wherein the control unit is set to a square root of a value obtained by subtracting a square value of a reactive power command value whose value is limited from a multiplier value.

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