KR101375256B1 - Parallel converter operation system of wind power generator - Google Patents

Abstract

A parallel converter operation system of a wind power generator is disclosed. The parallel converter operation system of a wind power generator according to an embodiment of the present invention comprises; multiple power converting units which disperse generation power produced in a generator by being connected in parallel; a monitoring unit which sets a temperature limit value for the reduction operation of the power converting unit and collects a temperature of a bonding unit of insulated gate bipolar transistor (IGBT) modules included in the power converting unit or a temperature of a heat radiation plate in which the IGBT module is attached; and a control unit which reduces operation capacity of a first power converting unit including the IGBT module which exceeds a limit value by comparing the temperature of the boding unit of the separate IGBT module and the temperature of the heat radiation plate with limit value setting information. The control unit increases operation capacity of a second power converting unit. [Reference numerals] (400) Monitoring unit; (500) Control unit; (AA) Synchronous generator; (BB) Filter; (CC) Current braker

Description

PARALLEL CONVERTER OPERATION SYSTEM OF WIND POWER GENERATOR}

The present invention relates to a parallel converter operating system of a wind turbine.

In general, a wind power generator rotates the central shaft by the rotational force of a plurality of blades rotated by the wind, and the rotational force of the shaft is increased to the operating speed of the generator through a transmission and is transmitted to the generator. To produce. In addition, the power produced by the generator is converted into a power suitable for supplying the system through the converter system is supplied to the power system.

Recently, as a large-capacity wind power generator is installed, as its power production increases, the use of a parallel converter system that distributes a large amount of power by using a plurality of power converters has been proposed.

The power converter uses an Insulated Gate Bipolar Transistor (IGBT) as a switch for restoring a signal to a real voltage using a pulse width modulation (PWM) scheme.

The IGBT can be simplified by the sum of the conduction losses caused by the conduction state voltage when the current is turned on and the turn-on / off switching losses caused by the switching of voltage and current. This loss can increase the temperature of the IGBT chip, which can break the connection between the passage of the current and the bonding, which is the medium connecting the IGBT chip, so the junction temperature of the IGBT must be kept within the limit.

Therefore, in order to properly dissipate the heat of the IGBT, a cooling medium may be attached to allow the heat to be transferred to a medium having a low temperature, resulting in lowering the junction temperature of the IGBT. As described above, in installing the power converter, it is very important to design a heat dissipation to minimize thermal resistance of each part.

Referring to FIG. 1, in spite of the conventional heat dissipation design, if the heat of the IGBT is not properly released or the inflow temperature of the cooling medium rises or the overload current flows continuously in the IGBT, at least one IGBT junction temperature is maintained. If it does, stop driving to protect the IGBT.

That is, in the parallel converter system in which three power converters are connected in parallel and are in charge of 1/3 power conversion as shown in FIG. 1, when the temperature rises above the limit even with one IGBT in the power converter, the entire converter system. The disadvantage is that the system must be shut down.

This is because the converter system has to wait until the temperature is lowered in the state in which the operation of the entire power converter is stopped, there is a problem that the long time non-operation time of the generator is increased, causing a huge loss in the power production of the wind turbine.

An embodiment of the present invention is to provide a parallel converter operating system that guarantees a stable continuous operation without stopping even if the temperature of the IGBT module provided in the parallel converter of the wind turbine exceeds the limit.

According to an aspect of the present invention, a parallel converter operating system of a wind power generator, a plurality of power converters connected in parallel to distribute the generated power generated by the generator; A monitoring unit configured to set a temperature limit value for the reduction operation of the power converter and collect junction temperature of the IGBT modules included in the power converter or a temperature of a heat sink to which the IGBT module is attached; And comparing the junction temperature of the individual IGBT module or the temperature of the heat sink with the limit setting information, thereby reducing the operating capacity of the first power converter including the IGBT module exceeding the limit, and operating capacity of the remaining second power converter. It includes a control unit for increasing the.

In addition, the power conversion unit, an inverter for converting the AC power produced by the generator into direct current; A direct current link storing the converted direct current power in a capacitor at a constant voltage; And a converter for converting DC power stored in the capacitor into AC power for grid linkage, wherein the inverter and the converter may each include a plurality of IGBT modules and individual temperature sensors of the IGBT module.

In addition, the power converter may include a breaker to block the connection from the generator and the grid in accordance with the control signal applied when the temperature of the at least one IGBT module exceeds the limit.

In addition, the breaker may be installed on the DC link side.

The controller may divide and distribute the reduced operating capacity of the first power converter to the remaining second power converters.

The controller may determine whether a reduction operation is possible when the temperature of the IGBT module of the first power conversion unit exceeds the limit value. If the reduction operation is impossible, the control unit transmits a control signal to the breaker of the first power conversion unit to be connected. And the remaining second power conversion unit may be operated in a rated operation.

On the other hand, a parallel converter driving system of a wind turbine generator according to an aspect of the present invention, a plurality of power converters connected in parallel to distribute the generated power produced by the generator; Set a safe operation area for the reduction operation of the power converter, and at least one of the switching frequency, thermal resistance, cooling water inflow temperature and the current flowing to the power converter of the IGBT modules included in the power converter in real time A monitoring unit for estimating junction temperature of individual IGBT modules; And comparing the junction temperature of the individual IGBT modules with the safe driving region to reduce the driving capacity of the first power converter including the IGBT module within the safe driving region and increase the operating capacity of the remaining second power converter. It includes a control unit.

In addition, the safe operation region includes a predetermined lower limit temperature and an upper limit temperature, and the controller generates an alarm when the junction temperature of the IGBT module exceeds the lower limit temperature, and between the lower limit temperature and the upper limit temperature for a predetermined time. If so, the power generation reduction operation can be controlled.

In addition, when the junction temperature of the IGBT module exceeds the upper limit temperature, the controller may transmit a control signal to the breaker of the first power converter to block the linkage between the generator and the grid.

The control unit may increase the operating capacity by operating the remaining second power conversion unit in a rated operation when the first power converter is cut off.

According to an embodiment of the present invention, even if the temperature of the IGBT module included in the parallel converter of the wind turbine exceeds the limit value, the non-operation time of the generator is reduced by performing continuous operation without stopping through reduction operation and elastic operation load distribution. The power generation efficiency can be improved.

In addition, it is possible to estimate the junction temperature of the IGBT by real-time sensing the IGBT module-related thermal resistance, the temperature of the coolant to cool the entire converter, the current flowing through the power converter.

 In addition, the safe operation area of the converter is set to two limit values, and the load of the converter is limited or increased so that the junction temperature is maintained within the safe operation area limit value, thereby enabling continuous and stable power generation reduction operation.

1 is a block diagram schematically illustrating a structure of a general parallel converter.
2 shows a thermal equivalent circuit of a typical IGBT.
3 is a flowchart schematically illustrating a protection method of a general parallel converter.
4 is a block diagram showing a parallel converter operating system of a wind turbine according to an embodiment of the present invention.
5 is a flowchart illustrating a method of reducing driving of a parallel converter system according to a first exemplary embodiment of the present invention.
6 is a view illustrating a junction temperature calculation method of an IGBT module according to a second embodiment of the present invention.
7 illustrates a method of reducing driving of a parallel converter system according to a second exemplary embodiment of the present invention.
8 is a simulation circuit for verifying the function of the reduced driving method of the parallel converter according to an embodiment of the present invention.
9 is a graph illustrating a result waveform according to the simulation of FIG. 8.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise. Also, the terms " part, "" module," and " module ", etc. in the specification mean a unit for processing at least one function or operation and may be implemented by hardware or software or a combination of hardware and software have.

Throughout the specification, the terms first or second etc. may be used to describe various elements, but the elements should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another, for example, without departing from the scope of the rights according to the inventive concept, the first component may be called a second component, and similarly The second component may also be referred to as the first component.

Now, a parallel converter driving system of a wind power generator according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Before describing an embodiment of the present invention, the structure of the conventional parallel converter system and its protection method will be described with reference to FIGS. 1 to 3 below.

1 is a block diagram schematically illustrating a structure of a general parallel converter.

Referring to FIG. 1, a conventional parallel converter system 10 distributes power generated by a synchronous generator by connecting a plurality of power converters (power converters ## 1 to # 3) in parallel. .

The plurality of power converters (power converters ## 1 to # 3) each include an inverter inverter (inverters ## 1 to # 3) and a grid converter (converters ## 1 to # 3). And a direct current link (DC-Link_ # 1 to # 3) connecting the inverters (inverters ## 1 to # 3) and the converters (converters ## 1 to # 3), respectively.

Here, the inverters (inverters _ # 1 to # 3) and the converters (converters _ # 1 to # 3) of the converter system 10 as a whole include three IGBT modules, respectively, as viewed in the parallel converter system 10 as a whole. In this case, all 18 (6x3) IGBT modules (INV_IGBT _ # _ 1 to CON_IGBT_ # 3_3) are configured.

The junction temperature (INV _ # _ 1_Tj to CON_ # 3_3_Tj) of each IGBT module (INV_IGBT _ # _ 1 to CON_IGBT_ # 3_3) is measured through a thermal equivalent circuit.

2 shows a thermal equivalent circuit of a general IGBT.

Referring to FIG. 2, through the thermal equivalent circuit of the IGBT, the junction temperature of the IGBT (Tj: IGBT junction temperature), the IGBT case temperature (Tc: IGBT case temperature h), and the heat sink temperature (Th: heat-sink temperature) , Ambient temperature (Ta), thermal resistance between junction and case (Zth_jc), thermal resistance between case and heat sink (Zth_ch: thermal impedence between case and heat-sink), The thermal resistance (Zth_ha: thermal impedence between heat-sink and ambient) can be measured.

In the structure of the conventional parallel converter, when at least one of the 18 IGBT modules exceeds an individual temperature suggestion, the protection sequence of the parallel converter system is shown in FIG. 3.

3 is a flowchart schematically illustrating a protection method of a general parallel converter.

Referring to FIG. 3, the converter protection logic operation for limiting the IGBT junction temperature rise is started to measure the junction temperature Tj of each IGBT module (INV_IGBT _ # _ 1 to CON_IGBT_ # 3_3).

At this time, the converter system 10 is at least one of the individual junction temperature (INV _ # _ 1_Tj ~ CON_ # 3_3_Tj) of each IGBT module (INV_IGBT _ # _ 1 ~ CON_IGBT_ # 3_3) exceeds the limit (S10-1 ~ S10- At least one of 18, e.g., reduces the generated power to a predetermined slope to prevent equipment damage and then stops the operation of the converter system at zero power and then waits.

That is, when the temperature of at least one IGBT module rises above the limit value, the operation of the entire converter system is stopped and waited until the temperature drops (S20).

At this time, the converter system 10 operates as a protection limit value of the converter that is higher than the higher generation command, so that when the IGBT junction temperature Tj does not reach below the limit, it stops even if the operation command comes from the upper level. Will be maintained.

Such a conventional converter system has been pointed out as a problem that a huge loss occurs in the power generation of the wind power generator because the power generation efficiency is reduced due to inefficient operation due to the stop or increase the long operation time.

Accordingly, an embodiment of the present invention provides a parallel converter operating system that ensures stable continuous operation without stopping even if the temperature of the IGBT module provided in the parallel converter of the wind turbine exceeds the limit as follows.

4 is a block diagram showing a parallel converter operating system of a wind turbine according to an embodiment of the present invention.

Referring to FIG. 4, the parallel converter system 1000 of a wind power generator according to an embodiment of the present invention includes a plurality of power converters 110, 200, and 300, a monitoring unit 400, and a controller 500. Include.

The plurality of power converters 110, 200, and 300 are connected in parallel to distribute the generated power generated by the synchronous generator and convert the generated power into power for linkage with the grid. Hereinafter, a description will be given on the assumption that three power converters divide a generated power by 1/3 to process power, but the number of power converters is not limited thereto.

In addition, since the plurality of power converters 100, 200, and 300 all have the same configuration, the first power converter 100 will be described as a representative.

The first power converter 100 includes a first inverter 110, a first converter 120, a first DC link 130, and a first breaker 140.

The first inverter 110 converts the AC power produced by the synchronous generator into a direct current, and the temperature of the three IGBT modules 111-1 to 111-3 and each of the IGBT modules 111-1 to 111-3, respectively. The individual temperature sensors 112-1 to 112-3 to measure are included.

The first converter 120 converts the converted DC power into AC power for grid linkage, and the temperature of the three IGBT modules 121-1 to 121-3 and the respective IGBT modules 121-1 to 121-3. It includes an individual temperature sensor (122-1 ~ 122-3) for measuring each.

The first DC link 130 is positioned between the first inverter 110 and the first converter 120 to store the DC power converted by the first inverter 110 at a constant voltage in a capacitor, and for alternating current conversion. Provided to the first converter 120.

When the temperature of at least one IGBT module in the first power converter 100 exceeds the limit, the first breaker 140 cuts off the linkage between the source and the load according to the control signal applied.

The first breaker 140 is preferably installed on the DC side, but is not limited thereto. The first breaker 140 may be installed as the first breaker 140 'on the AC side.

However, in FIG. 4, the reason why the first breaker 140 is installed on the DC side is that a 3-pole blocking device is required to cut off the AC side, while the DC side can be blocked by 1-pole, thereby simplifying installation. The size of the blocking device can also be reduced.

On the other hand, the configuration of the monitoring unit 400 and the control unit 500 will be described by dividing the first embodiment and the second embodiment below.

[First Embodiment]

The monitoring unit 400 sets a temperature limit value for the reduction operation of the power converter, and collects the junction temperature of the IGBT module or the temperature of the heat sink to which the IGBT module is attached through the individual sensor.

The controller 500 controls overall operations for the operation of the parallel converter system 1000.

The control unit 500 compares the junction temperature of the individual IGBT module collected through the monitoring unit 400 or the temperature of the heat sink with the proposed value setting information to control the reduction operation of the power converter when the at least one IGBT module is above the limit value. do.

5 is a flowchart illustrating a method of reducing operation of a parallel converter system according to a first embodiment of the present invention.

Referring to FIG. 5, the controller 500 periodically collects junction temperatures of a plurality of IGBT modules through the monitoring unit 400 (S101).

If the junction temperature of the IGBT module of one power converter is greater than or equal to the limit value (S102, YES), the controller 500 determines whether a reduction operation of the power converter is possible (S103). In this case, the controller 500 may check whether the corresponding power converter has exceeded the limit value, and determine that the power converter may perform a reduction operation in the case of a temporary temperature increase due to an increase in load without a separate failure.

In step S103, when it is determined that the reduction operation of the power conversion unit is possible (S103; YES), the control unit 500 operates by reducing the operation capacity of the one power conversion unit and increases the operation load of the remaining two power conversion units. (S104). In this case, the controller 500 may divide and distribute the reduced operating capacity to the remaining power converter.

On the other hand, in step S103, if it is determined that the reduction operation of the power conversion unit is impossible (S103; No), the control unit 500 transmits a control signal to the breaker of the one power conversion unit to block the linkage, the remaining two power The converter is operated at the maximum rated operation to increase the operating load (S105).

On the other hand, when the junction temperature of the IGBT modules of the two power converters are each greater than or equal to the limit value (S106, Yes), the controller 500 determines whether the reduction operation of the power converter is possible (S107).

In step S107, when it is determined that the reduction operation of the power conversion unit is possible (S107; YES), the control unit 500 operates by reducing the operation capacity of the two power conversion units and increases the operation load of the remaining one power conversion unit. (S108).

On the other hand, in step S107, if it is determined that the reduction operation of the power conversion unit is impossible (S107; No), the control unit 500 transmits a control signal to the breaker of the two power conversion unit to block the connection, the remaining one power The converter is operated at the maximum rated operation to increase the operating load (S109). Here, the maximum rated operation means operating in the maximum operating conditions in consideration of the specifications and performance of the power converter.

On the other hand, when the junction temperature of the IGBT modules of the three power converters are each greater than or equal to the limit value (S110, YES), the controller 500 determines whether the reduction operation of the power converter is possible (S111).

In step S111, when it is determined that the reduction operation of the power conversion unit is possible (S111; YES), the control unit 500 operates by reducing the operation capacity of the three power conversion units (S112). At this time, the control unit 500 may reduce the amount of power generated by adjusting the torque speed of the synchronous generator, if necessary.

On the other hand, in step S111, if it is determined that the reduction operation of the power converter is not possible (S111; No), the control unit 500 cuts off the current breaker on the grid side and stops the operation of the converter system (S113).

The reduction operation of the converter system 1000 described above is continued until the junction temperature of the IGBT module exceeding the limit temperature falls below it, and then returns to normal operation.

[Second Embodiment]

The monitoring unit 400 sets a converter safe operation area including an upper limit temperature T1 and a lower limit temperature T2 for the reduction operation of the power converter. Here, the upper limit temperature T1 is a limit for stopping the operation of the power converter, and the lower limit temperature T2 is a limit for the reduction operation.

The monitoring unit 400 calculates the temperature of the IGBT junction by using a parameter to be used in the junction temperature estimation equation of the IGBT module in the power converter from the individual temperature sensor. In this case, the junction temperature Tj of the IGBT module may be estimated based on at least one of switching frequency, heat resistance related to individual IGBT modules, cooling water inflow temperature, and current flowing to the power converter, which are information related to power generation reduction operation detected in real time. have.

For example, FIG. 6 illustrates a junction temperature calculation method of an IGBT module according to a second embodiment of the present invention.

Referring to FIG. 6, the monitoring unit 400 according to the second embodiment of the present invention monitors the overall operation of the converter system 1000, calculates an IGBT module related thermal resistance coefficient (S210), and a switching period. Calculate the average loss of the IGBT module during (cycle) (S220). At this time, the loss of the IGBT module includes the switching loss and the conduction loss, and the average loss can be obtained by averaging the switching period Ts.

In addition, the monitoring unit 400 calculates the temperature of the IGBT junction by multiplying the thermal resistance of the steady state and the average loss (S230).

The control unit 500 compares the junction temperature of the IGBT module estimated by the monitoring unit 400 with the safety operating area (CSOA) setting information, and reduces the power conversion unit when the junction temperature of the at least one IGBT module enters the safe operation area. Perform the operation.

On the other hand, Figure 7 shows a reduction operation method of a parallel converter system according to a second embodiment of the present invention.

Referring to FIG. 7, the converter system 1000 according to the junction temperature Tj of the IGBT module calculated as a parameter according to an embodiment of the present invention varies within and outside the limits of the safe operation area CSOA on a time axis. Show you how to drive.

When the estimated junction temperature Tj of the IGBT module is smaller than the lower limit temperature T2 (Tj <T2), the controller 500 normally controls the operation of the power converter.

When the junction temperature Tj of the IGBT module exceeds the lower limit temperature T2, the controller 500 generates an alarm and the safe operation region CSOA for a predetermined time (eg, 10 sec) for the junction temperature Tj of the IGBT module. ) Is maintained (T1 > Tj > T2) to control the power generation reduction operation of the power converter.

When the junction temperature Tj of the IGBT module is lowered below the lower limit temperature T2 according to the continuous power conversion unit power generation reduction operation, and the control unit 500 exceeds a predetermined time (eg, 10 sec), power conversion is normally performed again. Control negative driving.

On the other hand, the controller 500 generates an alarm and stops the operation of the power converter when the junction temperature Tj of the IGBT module exceeds the upper limit temperature T1 as well as the lower limit temperature T2 (Tj> T1).

As described above, it is apparent that the method for reducing driving of the parallel converter system according to the second exemplary embodiment of the present invention can be applied to the converter protection logic operation described with reference to FIG. 5.

8 is a simulation circuit for verifying the function of the reduced driving method of the parallel converter according to the embodiment of the present invention.

Referring to FIG. 8, two parallel implementations were used to shorten the simulation time. The two back-to-back converters were independently driven by three-wound transformers, and the energy flowing from the grid was again generated. In the system, only the loss of power is introduced.

9 is a graph showing a result waveform according to the simulation of FIG. 8.

Referring to FIG. 9, two parallel-connected converter modules reach about 0.41 seconds at a rated power of 2.5 MW, and one converter module (eg, the first power converter) performs a reduction operation at 0.45 seconds. The remaining converter module (eg, the second power converter) normally operates within the allowable capacity.

Therefore, although the rated power cannot be generated for a while, the continuous operation of the converter system is possible, and the reduction operation is released in about 0.78 seconds to return to the rated power generation operation.

As described above, according to an embodiment of the present invention, even if the temperature of the IGBT module included in the parallel converter of the wind turbine exceeds the limit value, the non-operation of the generator is performed continuously without stopping through the reduction operation and the elastic operation load distribution. There is an effect that can reduce the time and improve the power generation efficiency.

In addition, there is an advantage that the junction temperature of the IGBT can be estimated by real-time sensing of the IGBT module-related thermal resistance, the temperature of the coolant to cool the entire converter, the current flowing through the power converter.

 In addition, the safe operation area of the converter is set to two limits, and the load of the converter is limited or increased so that the junction temperature is maintained within the two limits, thereby enabling continuous and stable power generation reduction operation.

The embodiments of the present invention are not limited to the above-described apparatuses and / or methods, but may be implemented through a program for realizing functions corresponding to the configuration of the embodiment of the present invention, a recording medium on which the program is recorded And such an embodiment can be easily implemented by those skilled in the art from the description of the embodiments described above.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

1000: converter system 100, 200, 300: power converter
100: first power converter 110: first inverter
120: first converter 111-n, 121-n: IGBT module
112-n, 122-n: Temperature sensor 130: DC link
140: breaker 400: monitoring unit
500:

Claims (10)

A plurality of power converters connected in parallel to distribute the generated power generated by the generator;
A monitoring unit configured to set a temperature limit value for the reduction operation of the power converter and collect junction temperature of the IGBT modules included in the power converter or a temperature of a heat sink to which the IGBT module is attached; And
By comparing the junction temperature of the individual IGBT module or the temperature of the heat sink with the limit setting information, the operation capacity of the first power converter including the IGBT module exceeding the limit is reduced, and the operation capacity of the remaining second power converter is reduced. Including a control to increase,
The temperature limit includes a predetermined lower limit temperature and an upper limit temperature,
The control unit generates an alarm when the junction temperature of the IGBT module or the temperature of the heat sink exceeds the lower limit temperature, and when the temperature is between the lower limit temperature and the upper limit temperature for a predetermined time, the wind turbine for controlling the power generation reduction operation. Converter driving system. The method of claim 1,
Wherein the power conversion unit comprises:
An inverter for converting AC power produced by a generator into direct current;
A direct current link storing the converted direct current power in a capacitor at a constant voltage; And
It includes a converter for converting the DC power stored in the capacitor into AC power for grid linkage,
And said inverter and converter each comprise a plurality of IGBT modules and individual temperature sensors of said IGBT module. 3. The method according to claim 1 or 2,
The power conversion unit, a parallel converter operating system of the wind turbine including a breaker to block the linkage from the generator and the grid in accordance with the control signal applied when the temperature of the at least one IGBT module exceeds the upper limit temperature. The method of claim 3, wherein
The breaker is a parallel converter drive system of the wind turbine is installed on the DC link side. The method of claim 1,
The control unit, the parallel converter driving system of the wind power generator for dividing and distributing the reduced operating capacity of the first power converter to the remaining second power converter. The method of claim 1,
The controller determines whether a reduction operation is possible when the temperature of the IGBT module of the first power conversion unit exceeds the limit value, and if the reduction operation is impossible, transfers a control signal to the breaker of the first power conversion unit to block the linkage. And operating the remaining second power conversion unit in a rated operation. A plurality of power converters connected in parallel to distribute the generated power generated by the generator;
Set a safe operation area for the reduction operation of the power converter, and at least one of the switching frequency, thermal resistance, cooling water inflow temperature and the current flowing to the power converter of the IGBT modules included in the power converter in real time A monitoring unit for estimating junction temperature of individual IGBT modules; And
A control unit for reducing the operating capacity of the first power converter including the IGBT module in the safe operation area, and increasing the operation capacity of the remaining second power converter by comparing the junction temperature of the individual IGBT module with the safe operation area. Including,
The safe operation region includes a predetermined lower limit temperature and an upper limit temperature, and the controller generates an alarm when the junction temperature of the IGBT module exceeds the lower limit temperature, and when the temperature is between the lower limit temperature and the upper limit temperature for a predetermined time. Parallel converter operation system of wind power generator to control power reduction operation. delete The method of claim 7, wherein
The control unit, if the junction temperature of the IGBT module exceeds the upper limit temperature, a parallel converter operating system of the wind turbine for transmitting a control signal to the breaker of the first power conversion unit to block the linkage of the generator and the grid. The method of claim 7, wherein
The control unit, when the first power converter is cut off parallel converter operation system of the wind power generator to operate the remaining second power conversion unit in the rated operation to increase the operating capacity.

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