A method and system for monitoring the condition of IGBTs in the unloading circuit of a wind power converter.

Abstract

This invention discloses a method and system for monitoring the status of IGBTs in the unloading circuit of a wind turbine converter, including the following steps: real-time acquisition of the case temperature of the IGBTs in the unloading circuit of each converter of the wind turbine generator set, and feedback of the temperature signal to the converter controller; the converter controller calculates the maximum temperature increment ΔT of each IGBT during the operation of the unloading circuit based on the received temperature data. max The converter controller controls the maximum temperature increment ΔT for all IGBTs. max The system compares the IGBTs and obtains their status based on the comparison results; then, it executes corresponding strategies based on the IGBTs' status. This invention utilizes the IGBT's built-in NTC sensor to monitor the degradation behavior of IGBTs in high-power, multi-branch parallel unloading circuits, improving IGBT operational reliability, providing early warning of IGBT failure, enhancing circuit reliability, and preventing further damage.

Description

Technical Field

[0001] This invention relates to the technical field of wind power generation, and in particular to a method and system for monitoring the status of IGBTs in the unloading circuit of a wind power converter. Background Technology

[0002] During operation, wind turbine generators may experience a special condition where the power output of the generator-side converter significantly exceeds that of the grid-side converter due to faults within the generator itself or on the grid. This special condition typically occurs under the following conditions:

[0003] 1. A fault occurs in the wind turbine generator itself (such as an internal short circuit in the converter or the activation of the wind turbine safety chain), causing the converter grid-connected circuit breaker or the high-voltage ring network cabinet of the wind turbine generator to disconnect.

[0004] 2. A power grid failure (such as a short circuit) causes a sudden drop in voltage at the wind turbine generator's grid connection point.

[0005] The above operating conditions will cause extra energy to accumulate on the DC bus, resulting in an increase in the DC bus voltage. Currently, a common method to solve this power mismatch problem is to connect a DC unloading circuit between the positive and negative terminals of the DC bus. When the DC bus voltage exceeds a preset value, the IGBT (Insulated Gate Bipolar Transistor) of the unloading circuit turns on, and this extra energy is dissipated through the unloading resistor.

[0006] To achieve high-power applications in wind power converters, the power modules inside the converter typically employ a modular, multi-branch parallel configuration. Therefore, the unloading circuit is connected to the DC bus in multiple parallel configurations. Under conditions of frequent grid fault ride-throughs, specific load shedding strategies for wind turbine generators, multi-branch parallel applications, and low-cost requirements, high-power IGBTs, due to their harsh operating environment and inherent fatigue characteristics, are prone to functional degradation, making them the most vulnerable and highest-failure-rate devices in the unloading circuit. In parallel operation, if an IGBT in a single unloading circuit fails, it can cause overcurrent damage to other parallel IGBTs, failure of fault ride-through, and generator shutdown, resulting in power generation loss and increased operation and maintenance costs. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a condition monitoring method for IGBTs in the unloading circuit of a wind power converter. This method utilizes the NTC sensor built into the IGBT itself to monitor the degradation behavior of high-power multi-branch parallel unloading circuit IGBTs, thereby improving the reliability of IGBT operation, enabling early warning before IGBT failure, improving circuit reliability, and avoiding greater subsequent damage.

[0008] Another objective of this invention is to provide a status monitoring system for the IGBT in the unloading circuit of a wind power converter.

[0009] The objective of this invention is achieved through the following technical solution:

[0010] A method for monitoring the condition of IGBTs in the unloading circuit of a wind power converter, comprising the following steps:

[0011] S1. Real-time acquisition of the IGBT case temperature in the unloading circuit of each converter of the wind turbine generator set, and feedback of the temperature signal to the converter controller;

[0012] S2. When the unloading circuit is activated, the corresponding IGBT turns on, and the converter controller calculates the maximum temperature increment ΔT of each IGBT during the unloading circuit operation based on the received temperature data. max ;

[0013] S3. After the unloading circuit completes its operation, the converter controller measures the maximum temperature increment ΔT for all IGBTs. max The comparison is performed, and the state of the IGBT is obtained based on the comparison results;

[0014] S4. Execute the corresponding strategy based on the state of the IGBT.

[0015] Furthermore, in step S1, the case temperature of the IGBT is acquired using the NTC sensor built into the IGBT, and the temperature signal is fed back to the converter controller through the drive module built into the IGBT.

[0016] Furthermore, in step S2, the following operations are performed:

[0017] When a wind turbine generator experiences a grid disconnection fault or enters a fault ride-through state during normal operation, all unloading circuits are activated, and the corresponding IGBTs conduct, generating switching losses. The IGBT temperature will increase from its initial value T before conduction. initial Rise to peak T during fault ride peak The converter controller calculates the maximum temperature increment ΔT for each IGBT during the unloading circuit operation based on the received temperature data. max , △T max For peak value T peak With initial value T initial The difference.

[0018] Furthermore, in step S3, the following operations are performed:

[0019] After the unloading circuit completes its operation, the converter controller measures the maximum temperature increment ΔT for all IGBTs. max Comparison,

[0020] Such as the maximum temperature increment ΔT for each IGBT max Equal to and lower than the IGBT degradation criterion reference temperature ΔT refThis indicates that all IGBTs in the unloading circuit are in normal condition;

[0021] If there is an IGBT ΔT max Compared to the ΔT of other IGBTs max If the value exceeds the preset value, it indicates that the IGBT has degraded;

[0022] If there is IGBT ΔT max If the value is zero, it means that the IGBT has degraded and failed and is in an open circuit state.

[0023] Furthermore, if there is an IGBT's ΔT max ΔT higher than other IGBTs max If the degradation rate exceeds 15%, it indicates that the IGBT has degraded.

[0024] Furthermore, in step S4, the following operations are performed:

[0025] If the comparison result of step S3 shows that all IGBTs in the unloading circuit are in normal condition, then no operation is required;

[0026] If the comparison result of step S3 shows that the IGBT has degraded, the converter controller will generate a record and prompt that it needs to be checked or replaced during the next maintenance.

[0027] If the comparison result in step S3 shows that the IGBT has degraded and failed and is in an open circuit state, the converter controller will generate an alarm and prompt the user to replace it as soon as possible.

[0028] Another objective of this invention is achieved through the following technical solution:

[0029] A condition monitoring system for IGBTs in the unloading circuit of a wind power converter is provided to implement the aforementioned condition monitoring method for the IGBTs in the unloading circuit of a wind power converter, comprising:

[0030] The data acquisition module is used to collect the case temperature of the IGBT in the unloading circuit of each converter of the wind turbine generator set in real time.

[0031] The data transmission module is used to feed back the temperature signal acquired by the acquisition module to the converter controller;

[0032] The converter controller is used to calculate the maximum temperature increment ΔT of each IGBT during the unloading circuit operation based on the received temperature data. max Based on the comparison results, the state of the IGBT is obtained, and the corresponding strategy is executed according to the state of the IGBT.

[0033] Furthermore, the acquisition module is an NTC sensor built into the IGBT.

[0034] Furthermore, the data transmission module is a driver module built into the IGBT.

[0035] Furthermore, the converter controller calculates the maximum temperature increment ΔT for each IGBT during the unloading circuit operation based on the received temperature data. max ,

[0036] Such as the maximum temperature increment ΔT for each IGBT max Equal to and lower than the IGBT degradation criterion reference temperature ΔT ref This indicates that all IGBTs in the unloading circuit are in normal condition and no operation is required.

[0037] If there is an IGBT ΔT max Compared to the ΔT of other IGBTs max If the value exceeds the preset value, it indicates that the IGBT has degraded. The converter controller will generate a record and prompt that it needs to be checked or replaced during the next maintenance.

[0038] If there is IGBT ΔT max If the value is zero, it indicates that the IGBT has degraded and failed and is in an open circuit state. The converter controller will generate an alarm and prompt the user to replace it as soon as possible.

[0039] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0040] 1. This invention utilizes the built-in NTC sensor of the IGBT to monitor the degradation behavior of the IGBT in a high-power multi-branch parallel unloading circuit. Based on the electrical and thermal degradation characteristics of the IGBT itself, by comparing the temperature rise differences of the IGBT during the operation of each unloading circuit, early warning of IGBT failure is achieved, which improves the reliability of the circuit and avoids causing greater subsequent damage.

[0041] 2. Since the unloading circuit often operates under high temperature and high current conditions, the state of the IGBT after each operation is unknown. This invention can reduce the failure rate and maintenance cost of the unloading circuit without increasing the overall cost. It is practical and worth promoting. Attached Figure Description

[0042] Figure 1 This is a flowchart of the status monitoring method of the present invention.

[0043] Figure 2 This is a circuit diagram of the unloading circuit for the converter of a wind turbine generator set.

[0044] Figure 3 This is a temperature curve of the IGBT during the operation of the unloading circuit.

[0045] Figure 4 Temperature profiles for normal, degraded, and failed IGBTs. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0047] Example 1:

[0048] like Figure 1 As shown, this embodiment provides a method for monitoring the status of the IGBT in the unloading circuit of a wind power converter. The parallel structure of the wind turbine converter is as follows. Figure 2 As shown, converters 1 to n are connected in parallel, and each converter's unloading circuit's IGBT has a built-in NTC sensor and drive module; the above-mentioned status monitoring method includes the following steps:

[0049] S1. Real-time acquisition of the IGBT case temperature in the unloading circuit of each converter of the wind turbine generator set, and the temperature signal T of the IGBT in the unloading circuit of converter 1 to converter n. NTC_1 To T NTC_n Feedback is sent to the converter controller;

[0050] In this embodiment, the NTC sensor built into the IGBT can be used to collect the case temperature of the IGBT, and the temperature signal can be fed back to the converter controller through the drive module built into the IGBT. This reduces the failure rate of the unloading circuit and the operation and maintenance cost without increasing the overall cost.

[0051] S2. When the unloading circuit is activated, the corresponding IGBT turns on, and the converter controller calculates the maximum temperature increment ΔT of each IGBT during the unloading circuit operation based on the received temperature data. max Specifically, perform the following operations:

[0052] When a wind turbine generator experiences a grid disconnection fault or enters a fault ride-through state during normal operation, all unloading circuits are activated, and the corresponding IGBTs conduct, generating switching losses. The IGBT temperature will increase from its initial value T before conduction. initial Rise to peak T during fault ride peak ,like Figure 3 As shown, the converter controller calculates the maximum temperature increment ΔT for each IGBT during the unloading circuit operation based on the received temperature data. max , △T max For peak value T peakWith initial value T initial The difference.

[0053] S3. IGBTs undergo functional degradation over time, primarily manifested in IGBT bonding wire degradation, solder layer delamination, and chip metallization degradation. The corresponding electrical and thermal parameters of a degraded IGBT are an increase in collector-emitter turn-on voltage and thermal resistance. Therefore, the junction temperature or case temperature increment ΔT of a degraded IGBT during operation is significant. max The temperature increment is much higher than that of a normal IGBT. For IGBTs that have failed due to severe degradation, they are essentially open circuits when the Chopper circuit is activated, and there will be no temperature increment during operation. The temperature profiles of IGBTs in different states during the unloading circuit turn-on process are shown below. Figure 4 As shown. According to Figure 4 In this characteristic, after the unloading circuit completes its operation, the converter controller adjusts the maximum temperature increment ΔT for all IGBTs. max (△T max_1 ,△T max_2 ……△T max_n The comparison is performed, and the status of the IGBT is obtained based on the comparison result; specifically, the following operations are performed:

[0054] After the unloading circuit completes its operation, the converter controller measures the maximum temperature increment ΔT for all IGBTs. max Comparison,

[0055] Such as the maximum temperature increment ΔT for each IGBT max Equal to and lower than the IGBT degradation criterion reference temperature ΔT ref This indicates that all IGBTs in the unloading circuit are in normal condition;

[0056] If there is an IGBT ΔT max Compared to the ΔT of other IGBTs max If the value exceeds the preset value (e.g., more than 15%), it indicates that the IGBT has degraded.

[0057] If there is IGBT ΔT max If the value is zero, it means that the IGBT has degraded and failed and is in an open circuit state.

[0058] S4. Execute the corresponding strategy based on the IGBT's state; specifically, perform the following operations.

[0059] If the comparison result of step S3 shows that all IGBTs in the unloading circuit are in normal condition, then no operation is required;

[0060] If the comparison result of step S3 shows that the IGBT has degraded, the converter controller will generate a record and prompt that it needs to be checked or replaced during the next maintenance.

[0061] If the comparison result in step S3 shows that the IGBT has degraded and failed and is in an open circuit state, the converter controller will generate an alarm and prompt the IGBT to be replaced as soon as possible to avoid causing greater subsequent damage.

[0062] Example 2:

[0063] This embodiment provides a status monitoring system for the IGBT in the unloading circuit of a wind power converter, used to implement the aforementioned status monitoring method for the IGBT in the unloading circuit of a wind power converter, including,

[0064] The data acquisition module is used to collect the case temperature of the IGBT in the unloading circuit of each converter of the wind turbine generator set in real time.

[0065] The data transmission module is used to feed back the temperature signal acquired by the acquisition module to the converter controller;

[0066] The converter controller is used to calculate the maximum temperature increment ΔT of each IGBT during the unloading circuit operation based on the received temperature data. max Based on the comparison results, the state of the IGBT is obtained, and the corresponding strategy is executed according to the state of the IGBT.

[0067] Specifically, the acquisition module uses the NTC sensor built into the IGBT.

[0068] Specifically, the data transmission module uses the driver module built into the IGBT.

[0069] Specifically, the converter controller calculates the maximum temperature increment ΔT for each IGBT during the unloading circuit operation based on the received temperature data. max ,

[0070] Such as the maximum temperature increment ΔT for each IGBT max Equal to and lower than the IGBT degradation criterion reference temperature ΔT ref This indicates that all IGBTs in the unloading circuit are in normal condition and no operation is required.

[0071] If there is an IGBT ΔT max Compared to the ΔT of other IGBTs max If the value exceeds the preset value, it indicates that the IGBT has degraded. The converter controller will generate a record and prompt that it needs to be checked or replaced during the next maintenance.

[0072] If there is IGBT ΔT max If the value is zero, it indicates that the IGBT has degraded and failed and is in an open circuit state. The converter controller will generate an alarm and prompt the user to replace it as soon as possible.

[0073] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope disclosed in the present invention, based on the technical solution and inventive concept of the present invention, shall fall within the scope of protection of the present invention.

Claims

1. A method for monitoring the state of an IGBT in a wind power converter unloading circuit, characterized in that, Including steps, S1. Real-time acquisition of the IGBT case temperature in the unloading circuit of each converter of the wind turbine generator set, and feedback of the temperature signal to the converter controller; S2. When the unloading circuit is activated, the corresponding IGBT turns on, and the converter controller calculates the maximum temperature increment of each IGBT during the unloading circuit operation based on the received temperature data. ; Perform the following operations specifically: When a wind turbine generator experiences a grid disconnection fault or enters a fault ride-through state during normal operation, all unloading circuits are activated, and the corresponding IGBTs conduct, generating switching losses. The IGBT temperature will then rise from its initial value before conduction. Rise to peak during fault ride The converter controller calculates the maximum temperature increment of each IGBT during the unloading circuit operation based on the received temperature data. , Peak value With initial value The difference; S3. After the unloading circuit completes its operation, the converter controller adjusts the maximum temperature increment of all IGBTs. The comparison is performed, and the IGBT status is obtained based on the comparison results; specifically, the following operations are performed: After the unloading circuit completes its operation, the converter controller adjusts the maximum temperature increment of all IGBTs. Comparison, Such as the maximum temperature increment of each IGBT Equal to and below the IGBT degradation criterion reference temperature This indicates that all IGBTs in the unloading circuit are in normal condition; If there is an IGBT Compared to other IGBTs If the value exceeds the preset value, it indicates that the IGBT has degraded; If there is IGBT If the value is zero, it means that the IGBT has degraded and failed and is in an open circuit state; S4. Execute the corresponding strategy based on the state of the IGBT.

2. The method for monitoring the state of the IGBT in the unloading circuit of a wind power converter according to claim 1, characterized in that, In step S1, the case temperature of the IGBT is collected using the NTC sensor built into the IGBT, and the temperature signal is fed back to the converter controller through the drive module built into the IGBT.

3. The method for monitoring the state of the IGBT in the unloading circuit of a wind power converter according to claim 1, characterized in that, If there is an IGBT Higher than other IGBTs If the degradation rate exceeds 15%, it indicates that the IGBT has degraded.

4. The method for monitoring the state of the IGBT in the unloading circuit of a wind power converter according to claim 1, characterized in that, In step S4, the following operations are performed: If the comparison result of step S3 shows that all IGBTs in the unloading circuit are in normal condition, then no operation is required; If the comparison result of step S3 shows that the IGBT has degraded, the converter controller will generate a record and prompt that it needs to be checked or replaced during the next maintenance. If the comparison result in step S3 shows that the IGBT has degraded and failed and is in an open circuit state, the converter controller will generate an alarm and prompt the user to replace it as soon as possible.

5. A condition monitoring system for the IGBT in the unloading circuit of a wind power converter, characterized in that, The method for monitoring the state of the IGBT in the unloading circuit of the wind power converter as described in any one of claims 1 to 4. include, The data acquisition module is used to collect the case temperature of the IGBT in the unloading circuit of each converter of the wind turbine generator set in real time. The data transmission module is used to feed back the temperature signal acquired by the acquisition module to the converter controller; The converter controller is used to calculate the maximum temperature increment of each IGBT during the unloading circuit operation based on the received temperature data. Based on the comparison results, the state of the IGBT is obtained, and the corresponding strategy is executed according to the state of the IGBT.

6. The status monitoring system for the IGBT of the wind power converter unloading circuit according to claim 5, characterized in that, The acquisition module is an NTC sensor built into the IGBT.

7. The condition monitoring system for the IGBT of the wind power converter unloading circuit according to claim 5, characterized in that, The data transmission module is a driver module built into the IGBT.

8. The status monitoring system for the IGBT of the wind power converter unloading circuit according to claim 5, characterized in that, The converter controller calculates the maximum temperature increment of each IGBT during the unloading circuit operation based on the received temperature data. , Such as the maximum temperature increment of each IGBT Equal to and below the IGBT degradation criterion reference temperature This indicates that all IGBTs in the unloading circuit are in normal condition and no operation is required. If there is an IGBT Compared to other IGBTs If the value exceeds the preset value, it indicates that the IGBT has degraded. The converter controller will generate a record and prompt that it needs to be checked or replaced during the next maintenance. If there is IGBT If the value is zero, it indicates that the IGBT has degraded and failed and is in an open circuit state. The converter controller will generate an alarm and prompt the user to replace it as soon as possible.

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