KR20120002787A - Apparatus and method for restricting current of statcom(static compensator) - Google Patents

Abstract

PURPOSE: An apparatus for restricting a current of a STATCOM(static synchronous compensator) and a restricting method thereof are provided to improve the voltage stability of an electric power system by varying a pulse length according to a pole current(inverter current) of the STATCOM and system impedance. CONSTITUTION: A determining unit(240) determines over-current generation. A controller(260) controls an inverter current to be maintained below a rated current decides if the over current generation is determined. A calculating unit calculate system impedance based on an inverter current and an inverter voltage. A current sensing unit(220) senses the inverter current which is outputted from an inverter circuit. A voltage sensing unit senses the inverter voltage which is outputted from the inverter circuit.

Description

Technical Field [0001] The present invention relates to a current limiting device and method for a reactive power compensation controller,

The present invention relates to a current limiting apparatus and method for a reactive power compensation controller, and more particularly, to a current limiting apparatus and method for a reactive power compensation controller that limits a current of an inverter to a rated current in a reactive power compensation controller of a multi- .

In general, compensation for reactive power is essential for stable operation of an alternating current (AC) power system. In the AC power system, shunt reactors or shunter capacitors are used to compensate for reactive power.

In recent years, SVC (Static Var Compensation) and STATCOM (Static Synchronous Compensator), which utilize fast coercivity of power electronic devices, have been introduced as a reactive power source of the power system.

Pulse width modulation (PWM) and multi-level pulses are used for the reactive power compensation controller using inverter technology. In this case, in the case of the reactive power compensation controller used to compensate the reactive power of the power system, a multi-level pulse method is mainly used to reduce the operation loss.

1 to 3 are views for explaining a conventional reactive power compensation controller.

1, the multi-level pulse type reactive power compensation controller includes a first inverter 110, a second inverter 120, and a clamp 130, (+) Potential, positive potential, and (-) potential in the B phase (112), B phase (114), C phase (116), D phase (122), E phase Level pulses, and an intermediate transformer 20 for synthesizing pulses of three levels generated in the inverter circuit 100 into pulses of 24 levels.

The reactive power compensating controller controls the protection of the inverter circuit 100 when an abnormal state such as a short circuit or an eddy current occurs between the main transformer 10 for increasing the compensation voltage and the inverter circuit 100 and the controller 40 A protection relay 30 that cuts off the harmful circuit, a power supply 50 (hereinafter referred to as "UPS") that supplies stable power to the inverter circuit 100, a GPS 60 (gate power), a cooling system 70 , And a controller (40) for controlling the inverter circuit (100).

At this time, the controller 40 is configured as shown in Figs. 3 (a) to 3 (c) for generating three levels of pulses in the inverter circuit 100, and a variable for determining the width of the pulse generated in the inverter Gamma < RTI ID = 0.0 > (gamma) < / RTI > That is, the controller 40 controls the inverter to output a current having a fixed pulse width at each pole. Here, gamma (gamma) is a variable that affects the width of the electromotive force region in the pulse generated in the inverter.

In the case of the multi-level pulse method as described above, when a short circuit or a ground fault occurs in a substation installed with a reactive power compensating controller or in a nearby substation, an excessive current may flow to the inverter, and the power electronic device may be burned out. To prevent this, the reactive power compensation controller is disconnected from the power system when excessive current flows.

However, in the multi-level pulse type reactive power compensation controller, it is necessary to separate the reactive power compensation controller from the power system in order to prevent the occurrence of burnout of the power electronic device due to overcurrent flow, When a failure occurs in the reactive power compensating controller due to an accident, a certain amount of time is required for restarting the reactive power compensating controller. In this case, voltage stability of the power system is deteriorated.

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve the problems of the prior art described above, and it is an object of the present invention to provide a reactive power compensating controller in which the inverter current of the reactive power compensating controller is limited within a rated current even if a serious system accident occurs in a substation or a nearby system equipped with a multi- The present invention provides a current limiting apparatus and method of a reactive power compensation controller that prevents a component of a reactive power compensating controller from being burned out and prevents a reactive power compensating controller from being separated into a system so as to improve a voltage stability of a power system. .

According to an aspect of the present invention, there is provided a current limiting apparatus for a reactive power compensation controller including: a determination unit for determining whether an excessive current is generated based on an output value of an inverter circuit of a reactive power compensation controller; And a control unit for controlling the pulse width of each pole current of the reactive power compensation controller so as to maintain the inverter current at or below the rated current when it is determined that the excessive current is generated in the determination unit.

If it is determined that the overcurrent is generated in the determination unit, the control unit controls the inverter current to keep the inverter current below the rated current by increasing the width of the zero-potential region in the pulse of each pole current.

If the inverter current output from the inverter circuit is higher than the current setting value, the determination unit determines that an excessive current is generated.

If the system impedance of the inverter circuit is below the impedance set value, the determination unit determines that an excessive current is generated.

And a calculation section for calculating the system impedance based on the inverter current and the inverter voltage output from the inverter circuit.

And a current sensing unit for sensing an inverter current output from the inverter circuit.

And a voltage sensing unit for sensing an inverter voltage output from the inverter circuit.

According to another aspect of the present invention, there is provided a current limiting method for a reactive power compensation controller, comprising: a determining step of determining whether an excessive current is generated based on an output value of an inverter circuit of a reactive power compensation controller, ; And a control step of controlling the pulse width of each pole current of the reactive power compensation controller so as to keep the inverter current at or below the rated current when it is determined by the control unit that an excessive current is generated in the determination step.

In the control step, when it is determined that the overcurrent is generated in the determination unit, the control unit controls the inverter current to keep the inverter current below the rated current by increasing the width of the zero-potential region in the pulse of each pole current.

In the determination step, it is determined that an excessive current is generated when the inverter current outputted from the inverter circuit by the determination unit is equal to or larger than the current setting value.

In the determination step, if the system impedance of the inverter circuit is lower than the impedance set value by the determination unit, it is determined that an overcurrent is generated.

And a calculating step of calculating the system impedance based on the inverter current and the inverter voltage output from the inverter circuit by the calculating unit.

And a current sensing step of sensing an inverter current output from the inverter circuit by the current sensing unit.

And a voltage sensing step of sensing an inverter voltage output from the inverter circuit by the voltage sensing unit.

According to the present invention, the apparatus and method for limiting the current of the reactive power compensation controller vary the pulse width according to the pole current (inverter current) and the system impedance of the reactive power compensation controller, thereby maintaining the current of the inverter below the rated value, It is possible to improve the voltage stability of the power system without separating the power system from the power system.

Incidentally, the current limiting device and method of the reactive power compensating controller limits the current of the inverter to be kept below the rated value, thereby preventing the element of the reactive power compensating controller from being burned out and preventing the reactive power compensating controller from being separated into the system, It is possible to improve the voltage stability of the transistor.

1 to 3 are diagrams for explaining a reactive power compensation controller;
4 to 6 are diagrams for explaining a current limiting device of a reactive power compensation controller according to a first embodiment of the present invention.
7 is a flowchart illustrating a current limiting method of a reactive power compensation controller according to an embodiment of the present invention.
8 and 9 are views for explaining a current limiting device of a reactive power compensation controller according to a second embodiment of the present invention.
10 is a flowchart illustrating a current limiting method of a reactive power compensation controller according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings in order to facilitate a person skilled in the art to easily carry out the technical idea of the present invention. . In the drawings, the same reference numerals are used to designate the same or similar components throughout the drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Hereinafter, the current limiting device of the reactive power compensation controller according to the first embodiment of the present invention will be described in detail with reference to the accompanying drawings. 4 to 6 are views for explaining a current limiting device of a reactive power compensation controller according to a first embodiment of the present invention.

4, the current limiting device 200 of the reactive power compensation controller includes a current sensing unit 220, a determination unit 240, a control unit 260, and a storage unit 280.

The current sensing unit 220 senses an inverter current Ipole output from each pole of the inverter circuit 100. That is, the current sensing unit 220 is connected to each pole (i.e., A phase 112, B phase 114, C phase 116) of the first inverter 110 and each pole That is, the D phase 122, the E phase 124, and the F phase 126).

The determination unit 240 compares the inverter current sensed by the current sensing unit 220 with a predetermined current setting value to determine whether an excessive current is generated. That is, the determination unit 240 compares the inverter current Ipole sensed by the current sensing unit 220 with preset current values (for example, Iref1, Iref2, and Iref3) stored in the storage unit 280 It is determined whether an excessive current is generated (refer to FIG. 5). At this time, if the inverter current Ipole is equal to or greater than the current set values Iref1, Iref2, and Iref3 stored in the storage unit 280, the determination unit 240 determines that an excessive current is generated.

The determination unit 240 may determine whether an over-current is generated in a plurality of steps according to a current setting value. That is, the determination unit 240 sets a plurality of current setting values (i.e., Iref1, Iref2, and Iref3), compares the current setting values with the inverter current Ipole sensed by the current sensing unit 220, And determines the generation step. For example, assuming that Iref1, Iref2, and Iref3 are current setting values and Iref1> Iref2> Iref3 are the magnitudes of the current setting values, the determination unit 240 determines the inverter current Ipole ) Is in the range of Iref2 to Iref3, the excess current is generated in the first step. When the inverter current (Ipole) is in the range of Iref1 to Iref2, It is judged to be in the third stage of occurrence.

The control unit 260 changes the pulse width of the inverter current Ipole generated in each pole of the inverter circuit 100 according to the determination result of the determination unit 240 Is kept below the rated current. At this time, if the determination unit 240 determines that the overcurrent is generated, the control unit 260 increases the width of the overpotential region in the pulse width of the inverter current Ipole to control the inverter current Ipole to keep the rated current or less . The control unit 260 changes the pulse width of the inverter current Ipole which is the output current of the inverter circuit 100 according to the determination result of the determination unit 240 (that is, the overcurrent generation or overcurrent generation step) From the storage unit 280 and transmits the compensation value to the controller 40 that controls the inverter circuit 100. [ Accordingly, the controller 40 changes the gamma value to the compensation value received from the controller 260, and controls the inverter circuit 100 to output the inverter current whose pulse width is changed. Here, the compensation value is a value for increasing the width of the permanent potential region in the pulses of the respective pole currents of the inverter, and the control unit 260 increases the width of the permanent potential to control the inverter current to keep the rated current or less. The compensation value having a larger value is detected as the current generation step is higher.

For example, when the excess current is generated in the storage unit 280 as a compensation value (gamma gamma), Alpha3 is generated in the first stage, Alpha2 is generated in the second overcurrent generation stage, and Alpha1 is generated in the third overcurrent generation stage. 260 detects the compensation value corresponding to the overcurrent generation step determined by the determination unit 240 from the storage unit 280 and transmits the compensation value to the controller 40. [ That is, when the determination unit 240 determines that the overcurrent is generated in the first step, the control unit 260 detects Alpha1 as the compensation value from the storage unit 280 and transmits it to the controller 40. [ At this time, the compensation value (gamma) is set so as to have the magnitude of Alpha3 <Alpha2 <Alpha1 so that the higher the overcurrent generation step is, the greater the width of the pulse of the pulse.

The graph shown in Fig. 6 shows a case where the pulse width of the inverter current is fixed (i.e., when the gamma is fixed (Fig. 6A) and when the pulse width of the inverter current is changed 6 (b)). In this case, when the pulse width of the inverter current is fixed (that is, when the pulse width of the gamma is fixed), it can be seen that the current flowing in each pole of the inverter circuit 100 flows over the rated current. On the other hand, when the pulse width of the inverter current is changed (that is, the gamma The control unit 260 determines that the overvoltage width of the pulse generated in each pole of the inverter when the inverter current exceeds a certain level and generates an overcurrent, To the controller (40), so that the inverter And to limit the current within the rated current.

The storage unit 280 stores a current setting value as a basis for determining whether an overcurrent is generated and a compensation value for changing the pulse width of the inverter current. That is, the storage unit 280 stores one or more current setting values (for example, Iref1, Iref2, and Iref3) as a basis for determining whether an excessive current is generated in the determination unit 240, (For example, Alpha1, Alpha2, Alpha3 in Fig. 5). Here, the storage unit 280 stores a compensation value corresponding to a gamma value (see FIG. 3 (b)), which is a variable for determining the width of a pulse generated in the inverter.

Hereinafter, the current limiting method of the reactive power compensation controller according to the first embodiment of the present invention will be described in detail with reference to the accompanying drawings. 7 is a flowchart illustrating a current limiting method of a reactive power compensation controller according to an embodiment of the present invention.

First, the current sensing unit 220 measures an inverter current output from each pole of the inverter circuit 100 (S110). That is, the current sensing unit 220 senses the current of the first inverter 110 and the current of the first inverter 110, (Ipole) generated at each pole (i.e., D phase 122, E phase 124, F phase 126) of the inverter 120.

The determination unit 240 compares the inverter current sensed by the current sensing unit 220 with a current setting value to determine whether an overcurrent is generated (S120). At this time, if the inverter current Ipole is equal to or greater than the current set values Iref1, Iref2, and Iref3 stored in the storage unit 280, the determination unit 240 determines that an excessive current is generated. The determination unit 240 may determine whether an over-current is generated in a plurality of steps according to a current setting value. That is, the determination unit 240 sets a plurality of current setting values (i.e., Iref1, Iref2, and Iref3), compares the current setting values with the inverter current Ipole sensed by the current sensing unit 220, And determines the generation step.

If the determination unit 240 determines that excessive current is generated (S120; YES), the controller 260 detects a compensation value for changing the pulse width of the inverter current from the storage unit 280 (S132). That is, when the determination unit 240 determines that the overcurrent is generated, the control unit 260 controls the inverter circuit 100 to control the inverter current Ipole to be less than the rated current by narrowing the pulse width of the inverter current Ipole, From the storage unit 280, a compensation value set for changing the pulse width of the inverter current Ipole which is the output current of the inverter Ipole. At this time, if the overcurrent flows due to the overflow of the inverter current, the control unit 260 increases the width of the overvoltage region of the pulse generated at each pole of the inverter to compensate the inverter current to keep the inverter current below the rated current .

The control unit 260 transmits the detected compensation value to the controller 40. [ The controller 40 changes the pulse width of the inverter current using the compensation value received from the control unit 260 (S134). The controller 40 changes the gamma value to the compensation value received from the control unit 260. [ Accordingly, the inverter circuit 100 outputs a current having a width in the in-potential range of the pulse that is wider than the width of the in-phase region of the normal pulse.

The controller 40 supplies the inverter current whose pulse width is changed to be within the rated current to the intermediate transformer 20 (S136).

As described above, the current limiting device 200 and the method of the reactive power compensation controller according to the first embodiment of the present invention vary the pulse width according to the pole current (inverter current) and the system impedance of the reactive power compensation controller, There is an effect that the voltage stability of the power system can be improved without detaching the inverter from the system by keeping the current of the inverter below the rated value.

Incidentally, the current limiting device 200 and method of the reactive power compensation controller can prevent the element of the reactive power compensation controller from being burned out by limiting the current of the inverter to be kept below the rated value, and to prevent the reactive power compensating controller from being isolated into the system So that the voltage stability of the power system can be improved.

Hereinafter, the current limiting device 200 of the reactive power compensation controller according to the second embodiment of the present invention will be described in detail with reference to the accompanying drawings. 8 and 9 are views for explaining a current limiting apparatus 200 of a reactive power compensation controller according to a second embodiment of the present invention.

8, the current limiting device 200 of the reactive power compensation controller includes a voltage sensing unit 210, a current sensing unit 220, a calculation unit 230, a determination unit 240, a control unit 260, , And a storage unit 280.

The voltage sensing unit 210 senses the inverter voltage Vsys output from the inverter circuit 100.

The current sensing unit 220 senses the inverter current Isys output from the inverter circuit 100.

The calculating unit 230 calculates the system impedance of the inverter circuit 100 using the inverter voltage and the inverter current. That is, the calculating unit 230 substitutes the inverter voltage Vsys sensed by the voltage sensing unit 210 and the inverter current Isys sensed by the current sensing unit 220 into the following equation (1) ) Is calculated.

The determination unit 240 compares the system impedance of the inverter circuit 100 sensed by the calculation unit 230 with a predetermined impedance setting value to determine whether an excessive current is generated. That is, the determination unit 240 determines the impedance values (e.g., DELTA Z1, DELTA Z2, DELTA Z3) stored in the storage unit 280 by previously setting the systematic impedance DELTA Zsys calculated by the calculation unit 230, (Refer to FIG. 9). At this time, if the system impedance? Zsys calculated by the calculation unit 230 is equal to or lower than the impedance set value (for example,? Z1,? Z2,? Z3), the determination unit 240 determines that an overcurrent occurs.

The determination unit 240 may determine whether the excessive current is generated in a plurality of steps according to the impedance setting value. That is, the determination unit 240 sets a plurality of impedance set values (i.e.,? Z1,? Z2,? Z3) and compares the impedance set values with the system impedance? Zsys calculated by the calculating unit 230 Thereby determining an overcurrent generation step. For example, assuming that the impedance setting values? Z1,? Z2,? Z3 are stored in the storage unit 280 and the magnitude of each impedance set value is? Z1 <? Z2 <? Z3, ) Occurs when the system impedance (DELTA Zsys) falls within the range of DELTA Z2 to DELTA Z3, and when the system impedance (DELTA Zsys) falls within the range of DELTA Z1 to DELTA Z2, If the system impedance (? Zsys) is less than? Z1, it is determined that the overcurrent generation is in the third step.

The control unit 260 changes the width of the electromotive force area from the pulse of the inverter current Ipole generated in each pole of the inverter circuit 100 according to the determination result of the determination unit 240 Controls to keep the inverter current (Ipole) below the rated current. The control unit 260 determines whether or not the pulse of the inverter current Ipole which is the output current of the inverter circuit 100 is higher than the pulse width of the overcurrent Detects the compensation value set for changing the width of the region from the storage unit 280 and transmits it to the controller 40 that controls the inverter circuit 100. [ Accordingly, the controller 40 changes the gamma value to the compensation value received from the controller 260, and controls the inverter circuit 100 to output the inverter current whose pulse width is changed.

For example, when the excess current is generated in the storage unit 280 as a compensation value (gamma gamma), Alpha3 is generated in the first stage, Alpha2 is generated in the second overcurrent generation stage, and Alpha1 is generated in the third overcurrent generation stage. 260 detects the compensation value corresponding to the overcurrent generation step determined by the determination unit 240 from the storage unit 280 and transmits the compensation value to the controller 40. [ That is, when the determination unit 240 determines that the overcurrent generation is in the first step, the controller 260 detects Alpha3 as the compensation value from the storage unit 280 and transmits the detection result to the controller 40. [ At this time, the compensation value (gamma) is set so as to have the magnitude of Alpha3 <Alpha2 <Alpha1 so that the higher the overcurrent generation step is, the greater the width of the pulse of the pulse.

The storage unit 280 stores an impedance set value as a basis for determining whether an overcurrent is generated, and a compensation value for changing the pulse width of the inverter current. That is, the storage unit 280 stores one or more impedance setting values (e.g., DELTA Z1, DELTA Z2, DELTA Z3) as a basis for determining whether an excessive current is generated in the determination unit 240, (For example, Alpha1, Alpha2, and Alpha3 in Fig. 9) corresponding to the values are stored. Here, the storage unit 280 stores a compensation value corresponding to a gamma value (see FIG. 3 (b)), which is a variable for determining the width of a pulse generated in the inverter.

Hereinafter, the current limiting method of the reactive power compensation controller according to the second embodiment of the present invention will be described in detail with reference to the accompanying drawings. 10 is a flowchart illustrating a current limiting method of a reactive power compensation controller according to an embodiment of the present invention.

The current sensing unit 220 measures the inverter current output from the inverter circuit 100 (S210).

The voltage sensing unit 210 measures the inverter voltage output from the inverter circuit 100 (S220).

The calculating unit 230 calculates the system impedance of the inverter circuit 100 using the inverter voltage and the inverter current (S230). That is, the calculation unit 230 substitutes the inverter voltage Vsys sensed by the voltage sensing unit 210 and the inverter current Isys sensed by the current sensing unit 220 into the equation (1) ) Is calculated.

The determination unit 240 compares the system impedance of the inverter circuit 100 calculated by the calculation unit 230 with the impedance setting value to determine whether an excessive current is generated (S240). At this time, if the system impedance? Zsys is equal to or greater than the impedance set values? Z1,? Z2,? Z3 stored in the storage unit 280, the determination unit 240 determines that an overcurrent occurs. The determination unit 240 may determine whether an over-current is generated in a plurality of steps according to a current setting value. That is, the determination unit 240 sets a plurality of impedance set values (i.e.,? Z1,? Z2,? Z3) and compares the impedance set values with the system impedance? Zsys calculated by the calculating unit 230 Thereby determining an overcurrent generation step.

If the determination unit 240 determines that excessive current is generated (S240; YES), the control unit 260 detects a compensation value for changing the pulse width of the inverter current from the storage unit 280 (S252). That is, when the determination unit 240 determines that the excessive current is generated, the control unit 260 increases the width of the zero-potential region from the pulse of the inverter current Isys to control the inverter current Isys to be kept at or below the rated current From the storage unit 280, a compensation value set for changing the width of the permanent potential region in the pulse of the inverter current Isys which is the output current of the inverter circuit 100. At this time, the controller 260 detects a compensation value for controlling the width of the zero-potential region to increase in a pulse generated in each pole of the inverter when the system impedance falls below a certain level and an overcurrent occurs.

The control unit 260 transmits the detected compensation value to the controller 40. [ The controller 40 changes the pulse width of the inverter current using the compensation value received from the controller 260 (S254). The controller 40 changes the gamma value to the compensation value received from the control unit 260. [ Accordingly, the inverter circuit 100 outputs a current having a width in the in-potential range of the pulse that is wider than the width of the in-phase region of the normal pulse.

The controller 40 supplies the inverter current whose pulse width is changed to be within the rated current to the intervention transformer 20 (S256).

As described above, the current limiting device 200 and method of the reactive power compensation controller according to the second embodiment of the present invention vary the pulse width according to the pole current (inverter current) and the system impedance of the reactive power compensation controller, There is an effect that the voltage stability of the power system can be improved without detaching the inverter from the system by keeping the current of the inverter below the rated value.

Incidentally, the current limiting device 200 and method of the reactive power compensation controller can prevent the element of the reactive power compensation controller from being burned out by limiting the current of the inverter to be kept below the rated value, and to prevent the reactive power compensating controller from being isolated into the system So that the voltage stability of the power system can be improved.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but many variations and modifications may be made without departing from the scope of the present invention. It will be understood that the invention may be practiced.

10: main transformer 20: intervention transformer
30: Protection relay 40: Controller
50: UPS 60: GPS
70: cooling system 100: inverter circuit
110: First inverter 112: A phase
114: B phase 116: C phase
120: Second inverter 122: D phase
124: Phase E 126: Phase F
130: Clamp 200: Current limiting device
210: Voltage sensing unit 220: Current sensing unit
230: Calculator 240:
260: Control unit 280:

Claims (14)

A determination unit for determining whether an excessive current is generated based on an output value of an inverter circuit of the reactive power compensation controller; And
And a control unit for controlling the pulse width of each pole current of the reactive power compensation controller to maintain the inverter current at or below a rated current when the determination unit determines that an overcurrent is generated, Current limiting device. The method according to claim 1,
Wherein,
Wherein the control unit increases the width of the zero-potential region in the pulses of the pole currents when the determination unit determines that the excessive current is generated, and controls the inverter current to be maintained at or below the rated current. The method according to claim 1,
Wherein the determination unit determines that an overcurrent is generated when the inverter current output from the inverter circuit is equal to or greater than a current set value. The method according to claim 1,
Wherein,
And determines that an overcurrent is generated when the system impedance of the inverter circuit is lower than an impedance set value. The method according to claim 1,
And a calculation unit for calculating a system impedance based on the inverter current and the inverter voltage output from the inverter circuit. The method according to claim 1,
And a current sensing unit for sensing an inverter current outputted from the inverter circuit. The method according to claim 1,
And a voltage sensing unit for sensing an inverter voltage output from the inverter circuit. A determination step of determining whether an excessive current is generated based on an output value of the inverter circuit of the reactive power compensation controller by the determination unit; And
And a control step of controlling the pulse width of each pole current of the reactive power compensation controller so as to maintain the inverter current at or below a rated current when it is determined that the excessive current is generated in the determination step Current limiting method for reactive power compensation controller. The method of claim 8,
In the control step,
Wherein the controller controls the control unit to increase the width of the zero-potential region in the pulses of the respective pole currents so as to maintain the inverter current at or below the rated current when the determination unit determines that the excessive current is generated, Current limiting method. The method of claim 8,
In the determination step,
Wherein the determination unit determines that an excessive current is generated when the inverter current outputted from the inverter circuit is equal to or higher than a current setting value. The method of claim 8,
In the determination step,
Wherein the determination unit determines that an overcurrent is generated when the system impedance of the inverter circuit is equal to or lower than an impedance set value. The method of claim 8,
Further comprising a calculating step of calculating a system impedance based on the inverter current and the inverter voltage output from the inverter circuit by the calculating unit. The method of claim 8,
Further comprising a current sensing step of sensing an inverter current output from the inverter circuit by the current sensing unit. The method of claim 8,
Further comprising a voltage sensing step of sensing an inverter voltage output from the inverter circuit by a voltage sensing unit.

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