JP6809247B2 - Frequency conversion system controller - Google Patents

Description

The present invention is a rotary frequency conversion device of a frequency conversion system in which one of power systems having different frequencies is used as a power supply system and the other is used as a load system to connect and connect a rotary frequency converter and a static frequency converter in parallel. The present invention relates to a control device of a frequency conversion system that cooperatively controls a frequency conversion device and a static frequency conversion device.

The frequency conversion system is used when connecting power systems having different frequencies, and as a frequency conversion system, there is a frequency conversion system in which a rotary frequency conversion device and a static frequency conversion device are connected in parallel. Such a frequency conversion system is used, for example, when a power system having a commercial frequency of 50 Hz is used as a power supply system and power is supplied to a load system having a commercial frequency of 60 Hz.

The rotary frequency converter connects a synchronous motor and a synchronous generator, for example, rotates the synchronous motor at a frequency of 50 Hz to generate electric power having a frequency of 60 Hz from the synchronous generator. The number of poles of the synchronous generator is selected so as to generate electric power having a frequency of 60 Hz when rotating at a frequency of 50 Hz.

As a control device for a frequency conversion system in which such a rotary frequency converter and a static frequency converter are connected in parallel, the frequency conversion system utilizes the different characteristics of the rotary frequency converter and the static frequency converter. It is provided with a measuring means for measuring the output current of the frequency and a level detecting means for detecting that the output of the measuring means exceeds a certain value, and when the level detecting means detects that the output exceeds a certain value, it is a stationary type. By starting the frequency converter, the rotary frequency converter is operated in the region where the load current is small, the static frequency converter with less no-load loss is stopped, and the rotary type is used in the region where the load current exceeds a certain value. By operating a static frequency converter in addition to the frequency converter, the operating loss of the entire frequency conversion system can be reduced (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2000-134939

However, in Patent Document 1, the rotary frequency converter is operated in the region where the load current is small to stop the static frequency converter with little no-load loss, and the rotary frequency converter is stopped in the region where the load current exceeds a certain value. By operating a static frequency converter in addition to the frequency converter, cooperative control is performed so that the operating loss of the entire frequency conversion system can be reduced, but there is no consideration for suppressing voltage fluctuations in the load system.

When power is supplied to the load system by frequency conversion by a rotary frequency converter, if the load system is accompanied by large load fluctuations, or if a system accident of the power system occurs, the load system Voltage fluctuations may increase. That is, when there is a load fluctuation in the load system, a voltage fluctuation occurs due to a voltage drop in the impedance of the rotating machine of the rotary frequency converter. In the latter case, the rotation speed of the rotating machine of the rotary frequency converter fluctuates due to a system accident on the power supply system side, and the voltage fluctuation occurs due to the fluctuation of the speed electromotive force of the rotating machine due to the rotation speed deviation. To do. This voltage fluctuation converges with the passage of time, but it takes time to converge.

An object of the present invention is to provide a control device for a frequency conversion system capable of suppressing voltage fluctuations generated in a load system and quickly converging voltage fluctuations.

In the control device of the frequency conversion system according to the invention of claim 1, one of the power systems having different frequencies is used as a power supply system and the other is used as a load system, and a rotary frequency conversion device and a static frequency conversion device are connected in parallel and connected. In the control device of the frequency conversion system that cooperatively controls the rotary frequency conversion device and the static frequency conversion device of the related frequency conversion system, the static type so as to supply a predetermined power from the power supply system to the load system. The power supply control unit that controls the frequency converter and the invalid power adjustment command for adjusting the invalid power fluctuation accompanying the voltage fluctuation of the load system are calculated based on the voltage deviation between the voltage of the load system and the reference voltage. It is characterized in that it is provided with an invalid power fluctuation compensation unit that outputs to the power supply control unit.

In the invention of claim 1, the control device of the frequency conversion system according to the invention of claim 2 fluctuates the active power so that the active power supplied from the power supply system to the rotary frequency conversion device becomes the reference value thereof. It is characterized by including an active power fluctuation compensation unit that calculates an active power adjustment command for adjustment and outputs it to the power supply control unit.

According to the invention of claim 1, the reactive power fluctuation compensation unit that calculates a reactive power adjustment command for adjusting the reactive power fluctuation accompanying the voltage fluctuation of the load system based on the voltage deviation between the voltage of the load system and the reference voltage. Is provided, and the reactive power adjustment command is output to the power supply control unit to control the static frequency conversion device. Therefore, the voltage fluctuation of the load system can be suppressed and the voltage fluctuation can be quickly converged.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, it is effective for adjusting the active power fluctuation so that the active power supplied from the rotary frequency converter to the load system becomes the reference value thereof. Since the active power fluctuation compensation unit that calculates the power adjustment command is provided, it is possible to suppress the voltage fluctuation of the load system caused by the power fluctuation of the rotary frequency converter caused by the system accident, and the invalid power fluctuation and the power fluctuation can be suppressed. Regardless of the voltage fluctuation, the voltage fluctuation of the load system can be suppressed and the voltage fluctuation can be quickly converged.

The block diagram which shows an example of the control device of the frequency conversion system which concerns on 1st Embodiment of this invention. The graph which shows an example of the operation of the control device of the frequency conversion system which concerns on 1st Embodiment of this invention. The block diagram which shows an example of the control device of the frequency conversion system which concerns on 2nd Embodiment of this invention. The graph which shows an example of the operation of the control device of the frequency conversion system which concerns on 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described. FIG. 1 is a configuration diagram showing an example of a control device for a frequency conversion system according to the first embodiment of the present invention.

The frequency conversion system is used when connecting power systems having different frequencies. In FIG. 1, the left side shows a power system having a commercial frequency of 50 Hz, and the right side shows a power system having a commercial frequency of 60 Hz. Then, the power system having a commercial frequency of 50 Hz is used as the power supply system 11, the power system having a commercial frequency of 60 Hz is used as the load system 12, and the rotary frequency converter 13 and the static frequency converter 14 are connected in parallel and connected. Shown. A load such as an induction motor 15 (induction load) that consumes active power and reactive power and a resistance load 16 that consumes active power is connected to the load system 12.

The rotary frequency converter 13 is configured by connecting a synchronous motor 17 and a synchronous generator 18, and rotates the synchronous motor 17 at a frequency of 50 Hz to drive the synchronous generator 18, and power from the synchronous generator 18 to a frequency of 60 Hz. To generate. In this case, the synchronous generator 18 is driven by the synchronous motor 17 rotating at a frequency of 50 Hz, but the number of poles is selected so as to generate electric power having a frequency of 60 Hz. The power interchanged from the power supply system 11 to the load system 12 by the rotary frequency converter 13 is determined by the rating of the synchronous generator 18, and the active power and the ineffective power are determined by the induced electromotive force, the terminal voltage, and the reactance.

The static frequency conversion device 14 is configured by connecting a converter 19 that converts alternating current to direct current and an inverter 20 that converts direct current to direct current. The converter 19 converts alternating current power having a frequency of 50 Hz into direct current, and the converter 19 The converted direct current is converted into alternating current power having a frequency of 60 Hz by an inverter and supplied to the load system 12.

The control device 21 includes a power supply control unit 22, a reactive power fluctuation compensation unit 23, and an AC voltage deviation calculation unit 24. The power supply control unit 22 controls the static frequency conversion device 14 so as to supply predetermined power from the power supply system 11 to the load system 12.

The power supply control unit 22 includes a static frequency conversion converter control unit 25 (hereinafter referred to as a static FC converter control unit 25) for controlling the converter 19 of the static frequency converter 14, a first active power control unit 26, and the like. It has a first ineffective power control unit 27 and a DC voltage deviation calculation unit 28, and is a static frequency conversion inverter control unit 29 for controlling the inverter 20 of the static frequency conversion device 14 (hereinafter, static FC inverter control unit 29). It has a second active power control unit 30 and a second ineffective power control unit 31.

The DC voltage Vdc on the output side of the converter 19 is detected by the DC voltage detector 37, input to the DC voltage deviation calculation unit 28, and the DC voltage deviation ΔVdc with the target value Vdc0 is calculated. The DC voltage deviation ΔVdc calculated by the DC voltage deviation calculation unit 28 is input to the first active power control unit 26, and the first active power control unit 26 is set so that the DC voltage deviation ΔVdc becomes zero, that is, DC. A control command is output to the converter 19 via the static FC converter control unit 25 so that the voltage Vdc becomes the target value Vdc0. As a result, the converter 19 controls the active power received from the power supply system 11.

The first reactive power control unit 27 controls the reactive power at the interconnection point of the power supply system 11 of the converter 19, for example, in order to maintain the power factor of the interconnection point of the power supply system 11 of the converter 19 constant. A control command is output to the converter 19 via the static FC converter control unit 25 so that the reactive power reference value Qac0 required for the above is obtained. As a result, the invalid power at the interconnection point of the power supply system 11 of the converter 19 is controlled.

On the other hand, the static FC inverter control unit 29 outputs a control command to the inverter 20 so that the active power and the ineffective power supplied from the inverter 20 to the load system 12 become the target values. That is, the active power Pa supplied from the power supply system 11 to the load system 12 via the static frequency converter 14 is detected by the first active power detector 32, and the second active power control unit 30 of the power supply control unit 22. Outputs the active power control command Sp to the static FC inverter control unit 29 so that the active power Pa becomes the target value Par, and the static FC inverter control unit 29 converts the static frequency based on the active power control command Sp. It controls the inverter 20 of the device 14.

On the other hand, the invalid power Qa supplied from the inverter 20 to the load system 12 is detected by the invalid power detector 33, and the second invalid power control unit 31 of the power supply control unit 22 sets the invalid power Qa as the target value Qar. As described above, the static power control command Sq is output to the static FC inverter control unit 29, and the static FC inverter control unit 29 controls the inverter 20 of the static frequency converter 14 based on the static power control command Sq.

As a result, the active power Pa supplied from the power supply system 11 to the load system 12 in the static frequency converter 14 becomes the target value Par, and the ineffective power Qa supplied from the inverter 20 to the load system 12 becomes. It is controlled to reach the target value Qar.

Next, the reactive power fluctuation compensation unit 23 calculates the reactive power adjustment command ΔQr for adjusting the reactive power fluctuation accompanying the voltage fluctuation of the load system 12, and causes the second reactive power control unit 31 of the power supply control unit 22 to calculate. It is to output. The voltage fluctuation of the load system 12 is calculated by the AC voltage deviation calculation unit 24 as the voltage deviation ΔV. That is, the voltage of the load system 12 is detected by the voltage detector 36, the voltage deviation ΔV from the reference voltage Vac0 is calculated by the AC voltage deviation calculation unit 24, and is input to the reactive power fluctuation compensation unit 23. The reactive power fluctuation compensation unit 23 calculates the reactive power fluctuation required to suppress the voltage fluctuation based on the voltage deviation ΔV, and uses the reactive power adjustment command ΔQr as the reactive power adjustment command ΔQr to adjust the reactive power fluctuation accompanying the voltage fluctuation. It is output to the second reactive power control unit 31 of 22.

When the load of the load system 12 increases, the voltage drop caused by the internal reactance of the synchronous generator 18 becomes large, and when the load of the load system 12 decreases, the voltage drop caused by the internal reactance of the synchronous generator 18 becomes small. Become. The voltage fluctuation (voltage deviation ΔV) of the load system is represented by the following equation (1). ΔP is the active power fluctuation (active power deviation), ΔQ is the reactive power fluctuation (reactive power deviation), R is the internal resistance of the synchronous generator 18, and X is the internal reactance of the synchronous generator 18.
ΔV = ΔP ・ R + ΔQ ・ X≈ΔQ ・ X… (1)

In general, the internal resistance of a synchronous generator is sufficiently small with respect to the internal reactance. Therefore, as can be seen from Eq. (1), the voltage fluctuation (voltage deviation ΔV) of the load system is the reactive power fluctuation ΔQ accompanying the voltage fluctuation. It can be expressed, and the reactive power fluctuation ΔQ due to the voltage fluctuation is output to the second reactive power control unit 31 of the power supply control unit 22 as the reactive power adjustment command ΔQr for adjusting the reactive power fluctuation due to the voltage fluctuation.

The second disabled power control unit 31 adds the disabled power adjustment command ΔQr to the target value Qer of the disabled power Qa, and makes the static FC inverter a target value (Qar + ΔQr) including the disabled power fluctuation compensation portion. The static power control command Sq is output to the control unit 29, and the static FC inverter control unit 29 controls the inverter 20 of the static frequency converter 14 based on the static power control command Sq. As a result, the ineffective power Qa supplied to the load system 12 is controlled to be a target value (Qar + ΔQr) including the ineffective power fluctuation compensation amount.

FIG. 2 is a graph showing an example of the operation of the control device of the frequency conversion system according to the first embodiment of the present invention, and FIG. 2A is a graph showing the voltage fluctuation of the load system due to the load fluctuation of the load system 12. FIG. 2B is a graph showing voltage fluctuations of the load system 12 due to an accident on the power supply system 11 side. FIG. 2A shows a case where the induction motor 15 which is an inductive load is started, and FIG. 2B shows a case where the voltage of the power supply system 11 temporarily drops significantly due to an accident and recovers within a short time. Is shown.

In FIG. 2A, the solid line curve C1 shows the voltage of the load system 12 when the reactive power fluctuation compensation unit 23 controls the voltage fluctuation of the load system due to the load fluctuation of the load system 12. The dotted curve C2 is the voltage of the load system 12 when the voltage fluctuation suppression control by the reactive power fluctuation compensation unit 23 is not performed. When the voltage fluctuation suppression control is not performed, as shown by the dotted curve C2, the induction motor 15 which is an inductive load is started at the time point t1, the load fluctuates in the direction of increasing the load, and the voltage changes after the time point t1. A decreasing voltage fluctuation occurs, and there is a load fluctuation of a larger load increase at the time point t2, and a voltage fluctuation in which the voltage fluctuates between the time point t2 and the time point t4 occurs. On the other hand, when the voltage fluctuation suppression control is performed, as shown by the solid line curve C1, the voltage fluctuation occurs in a short time at the time points t1 and t2 when the load fluctuates, but the voltage fluctuation is well suppressed. You can see that.

In FIG. 2B, the solid line curve C11 shows the voltage fluctuation of the load system 12 due to the accident on the power supply system 11 side when the reactive power fluctuation compensation unit 23 controls the voltage fluctuation suppression. The voltage and dotted curve C12 is the voltage of the load system 12 when the reactive power fluctuation compensation unit 23 does not perform voltage fluctuation suppression control. When the voltage fluctuation suppression control is not performed, as shown by the dotted line curve C12, the power supply to the rotary frequency converter 13 is cut off due to the occurrence of a system accident at the time point ta immediately after the time point t11. Therefore, the rotary frequency converter 13 decelerates and the voltage of the load system 12 drops. Then, if the accident is recovered at the time point tb between the time point ta and the time point tc immediately after the time point t12, the power supply to the rotary frequency converter 13 is restarted, so that the rotary frequency converter 13 accelerates. The voltage of the load system 12 rises. Since the rotary frequency converter 13 is a synchronous machine, it operates so as to converge to the synchronous speed, and the terminal voltage (load system voltage) also operates to converge to the rated voltage. In the process, the rotary frequency converter 13 operates. Since No. 13 has inertia, the voltage reaches the maximum at the time point ct and the voltage starts to decrease, and the voltage gradually converges to the rated voltage after the time point ct while vibrating.

On the other hand, when the voltage fluctuation suppression control is performed, as shown in the solid line curve C11, the voltage fluctuation after the time ta when the system accident occurs is shown in the dotted line curve C12 when the voltage fluctuation suppression control is not performed. By comparison, it can be seen that the fluctuation range of the voltage is small and the voltage fluctuation converges early.

According to the first embodiment of the present invention, the voltage of the load system 12 is detected by the voltage detector 36, and the invalid power adjustment command ΔQr for adjusting the invalid power fluctuation accompanying the voltage fluctuation on the load system 12 side is issued. Since the fluctuation compensation unit 23 calculates and outputs the invalid power adjustment command ΔQr to the second invalid power control unit 31 of the power supply control unit 22 to control the inverter 20 of the static frequency converter 14, the load system 12 The invalid power Qa is controlled by the target value (Qar + ΔQr) including the compensation for the invalid power fluctuation, so that the voltage fluctuation of the load system 12 can be suppressed and the voltage fluctuation can be quickly converged.

Next, a second embodiment of the present invention will be described. FIG. 3 is a configuration diagram showing an example of a control device of the frequency conversion system according to the second embodiment of the present invention. In the second embodiment of the present invention, the active power adjustment command ΔPr for adjusting the active power fluctuation supplied from the rotary frequency converter 13 to the load system 12 is calculated with respect to the first embodiment shown in FIG. The active power fluctuation compensation unit 34 is additionally provided. The active power adjustment command ΔPr calculated by the active power fluctuation compensation unit 34 is output to the second active power control unit 30 of the power supply control unit 22, and the second active power control unit 30 is supplied to the load system 12. The inverter 20 is controlled by a target value (Par + ΔPr) including the active power fluctuation compensation. The same elements as those in FIG. 1 are designated by the same reference numerals, and redundant description will be omitted.

In FIG. 3, in addition to the reactive power fluctuation compensation unit 23 for adjusting the reactive power fluctuation due to the voltage fluctuation of the load system 12, the active power fluctuation compensation unit 34 is added to the first embodiment shown in FIG. It is provided. The active power fluctuation compensation unit 34 calculates the active power adjustment command ΔPr for adjusting the active power fluctuation supplied from the rotary frequency converter 13 to the load system 12, and controls the second active power of the power supply control unit 22. Output to unit 30. The active power Pb supplied from the rotary frequency converter 13 to the load system 12 is detected by the second active power detector 35 and input to the active power fluctuation compensation unit 34. The active power fluctuation compensation unit 34 calculates the active power adjustment command ΔPr for adjusting the active power fluctuation so that the active power Pb supplied from the rotary frequency converter 13 to the load system 12 becomes the reference value Pbr. , Output to the second active power control unit 30 of the power supply control unit 22.

The second active power control unit 30 is stationary so that the target value Par of the active power Pa supplied to the load system 12 via the static frequency converter 14 becomes the target value (Par + ΔPr) including the active power adjustment command ΔPr. The active power control command Sp is output to the type FC inverter control unit 29, and the static FC inverter control unit 29 outputs a control command to the inverter 20 of the static frequency conversion device 14 based on the active power control command Sp. As a result, the static frequency converter 14 is controlled so that the active power P supplied from the power supply system 11 to the load system 12 becomes a target value (Par + ΔPr) including the active power fluctuation compensation amount.

Therefore, the rotation speed of the rotary machine of the rotary frequency converter 13 fluctuates due to the system accident on the power supply system 11 side, and the active power supplied from the power supply system 11 to the synchronous electric power of the rotary frequency converter 13 fluctuates. Even if this is done, the active power fluctuation compensation unit 34 adjusts the active power fluctuation supplied from the rotary frequency converter 13 to the load system 12, so that the fluctuation of the rotation speed can be suppressed and the voltage fluctuation of the load system 12 can be suppressed. ..

FIG. 4 is a graph showing an example of the operation of the control device of the frequency conversion system according to the second embodiment of the present invention, and FIG. 4A shows the voltage fluctuation of the load system 12 due to the load fluctuation of the load system 12. The graph, FIG. 4B, is a graph showing the voltage fluctuation of the load system 12 due to the accident on the power supply system 11 side. FIG. 4A shows a case where the induction motor 15 which is an inductive load is started, and FIG. 4B shows a case where the voltage of the power supply system 11 temporarily drops significantly due to an accident and recovers in a short time. Is shown.

In FIG. 4A, the solid line curve D1 performs voltage fluctuation suppression control by the ineffective power fluctuation compensation unit 23 and the active power fluctuation compensation unit 34 with respect to the voltage fluctuation of the load system 12 due to the load fluctuation of the load system 12. The dotted curve D2 is the voltage of the load system 12 when the voltage fluctuation suppression control is not performed by the ineffective power fluctuation compensation unit 23 and the active power fluctuation compensation unit 34.

When the voltage fluctuation suppression control is not performed, as shown in the dotted line curve D2, it is the same as the dotted line curve C2 in the case of the first embodiment shown in FIG. 2A. On the other hand, even when the voltage fluctuation suppression control is performed, as shown in the solid line curve D1, it is almost the same as the solid line curve C1 in the case of the first embodiment shown in FIG. 2 (a). The suppression of the voltage fluctuation due to the load fluctuation of the load system 12 is almost the same as the case of the first embodiment shown in FIG. 2 (a). In this case, even if the active power fluctuation of the load system 12 is suppressed. It can be seen that the effect on suppressing the voltage fluctuation of the load system 12 is limited.

In FIG. 4B, the solid line curve D11 shows the voltage fluctuation suppression control by the ineffective power fluctuation compensation unit 23 and the active power fluctuation compensation unit 34 with respect to the voltage fluctuation of the load system 12 due to the accident on the power supply system 11 side. In this case, the voltage of the load system 12 and the dotted curve D12 are the voltages of the load system 12 when the voltage fluctuation suppression control by the ineffective power fluctuation compensation unit 23 and the active power fluctuation compensation unit 34 is not performed.

When the voltage fluctuation suppression control is not performed, as shown in the dotted line curve D12, it is the same as the dotted line curve C12 in the case of the first embodiment shown in FIG. 2 (b). On the other hand, when the voltage fluctuation suppression control is performed, as shown in the solid line curve D11, the voltage fluctuation after the time ta when the system accident occurs is on the dotted line curve D12 when the voltage fluctuation suppression control is not performed. By comparison, it can be seen that the fluctuation range of the voltage is small and the voltage fluctuation converges early. Further, it can be seen that the amplitude of the voltage fluctuation is small and converges early even when compared with the solid line C11 of the first embodiment shown in FIG. 2 (b).

According to the second embodiment of the present invention, in addition to the effect of the first embodiment, the active power fluctuation compensating unit 34 for adjusting the active power fluctuation supplied from the rotary frequency converter 13 to the load system 12 is provided. Therefore, regardless of whether the voltage fluctuation of the load system 12 is a reactive power fluctuation or an active power fluctuation, the voltage fluctuation of the load system 12 can be suppressed and the voltage fluctuation can be quickly converged. In particular, with respect to the voltage fluctuation of the load system 12 due to the accident on the power supply system 11 side, the voltage fluctuation can be suppressed and the voltage fluctuation can be converged at an early stage. In the above description, the rotary frequency converter 13 and the static frequency converter 14 are Although the case of one unit (one series) for each has been described, it can be applied even when a plurality of rotary frequency conversion devices 13 or static frequency conversion devices 14 are operated in parallel.

Although some embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

11 ... Power system, 12 ... Load system, 13 ... Rotary frequency converter, 14 ... Static frequency converter, 15 ... Induction motor, 16 ... Resistive load, 17 ... Synchronous motor, 18 ... Synchronous generator, 19 ... Converter , 20 ... Inverter, 21 ... Control device, 22 ... Power supply control unit, 23 ... Invalid power fluctuation compensation unit, 24 ... AC voltage deviation calculation unit,
25 ... Static FC converter control unit, 26 ... 1st active power control unit, 27 ... 1st ineffective power control unit, 28 ... DC voltage deviation calculation unit, 29 ... Static FC inverter control unit, 30 ... 2nd active power Control unit, 31 ... 2nd active power control unit, 32 ... 1st active power detection unit, 33 ... invalid power detection unit, 34 ... active power fluctuation compensation unit, 35 ... 2nd active power detection unit, 36 ... voltage detector , 37 ... DC voltage detector

Claims (2)

The rotary frequency converter and the stationary frequency converter of the frequency conversion system in which one of the power systems having different frequencies is used as the power supply system and the other is used as the load system to connect the rotary frequency converter and the static frequency converter in parallel. In the control device of the frequency conversion system that cooperates with the type frequency conversion device
A power supply control unit that controls the static frequency converter so as to supply a predetermined power from the power supply system to the load system.
Reactive power fluctuation compensation that calculates a reactive power adjustment command for adjusting the reactive power fluctuation accompanying the voltage fluctuation of the load system based on the voltage deviation between the voltage of the load system and the reference voltage and outputs it to the power supply control unit. A control device for a frequency conversion system, which is characterized by having a unit. The active power fluctuation for adjusting the active power fluctuation so that the active power supplied from the power supply system to the rotary frequency converter becomes the reference value is calculated and output to the power supply control unit. The control device for a frequency conversion system according to claim 1, further comprising a compensation unit.

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