Converter fault early warning and self-recovery control method for wind power system

Abstract

The invention provides a wind power system-oriented converter fault early warning and self-recovery control method, which comprises the following steps of: acquiring key parameters such as direct current bus voltage, current, power device temperature, cooling flow, bus capacitor voltage drift, device leakage current and the like of a converter in real time, and setting a static safety threshold interval; and the control system continuously compares the real-time monitoring value with the threshold value. According to the invention, key parameters such as DC bus voltage, current, power device temperature, cooling flow, bus capacitor voltage drift, device leakage current and the like of the converter are continuously acquired and compared, and when any parameter is close to or exceeds a safety threshold, the system immediately generates a fault early warning signal; by means of the method, potential risks can be recognized in advance in the early stage of equipment performance degradation or cooling efficiency reduction, real-time monitoring and active early warning of the fault trend are achieved, sudden shutdown or forced shutdown caused by detection lag is avoided, and the safety and stability of operation of the wind turbine generator system are improved.

Description

Technical Field

[0001] This invention relates to the field of wind power system technology, and in particular to a converter fault early warning and self-recovery control method for wind power systems. Background Technology

[0002] As a key device in wind turbine generator sets for energy conversion and grid connection control, the operation stability of the wind power converter is directly related to the power generation efficiency of the generator set and the security of the power grid. During long-term operation, the power devices (such as IGBTs and MOSFETs), drive circuits and cooling units inside the converter are subjected to high-frequency switching, voltage surges and thermal cycling stress, which can easily lead to performance degradation, switching failure or abnormal heat dissipation. In addition, the operating environment of wind turbines is complex, with large external temperature variations, high humidity, and a lot of dust. These factors may cause insulation aging of converter modules, bus capacitor drift, and local overheating, thereby causing system shutdown or grid connection failure. I. Traditionally, most wind power converters rely on alarm signals from the control system or manual inspections for fault detection. The abnormality is usually only discovered after the fault has occurred or the unit has been forced to shut down. Second, traditional converters are mostly single-channel or non-redundant structures. When a power module fails, the system needs to wait for manual reset or component replacement before it can resume operation. It cannot automatically isolate and transfer energy at the moment the fault occurs. To address this, a converter fault early warning and self-recovery control method for wind power systems is proposed. Summary of the Invention

[0003] In view of this, the present invention provides a converter fault early warning and self-recovery control method for wind power systems to solve or alleviate the technical problems existing in the prior art, and at least provides a beneficial option.

[0004] The technical solution of this invention is implemented as follows: A converter fault early warning and self-recovery control method for wind power systems includes the following steps: S1. Real-time acquisition of key operating parameters of wind turbine converter, including DC bus voltage, current, power device temperature, cooling flow rate, bus capacitor voltage deviation and device leakage current, and setting static safety threshold ranges for each parameter. S2. The control system continuously compares the real-time monitoring value with the static safety threshold range. When any parameter exceeds the threshold or its rate of change exceeds the set range, a fault warning signal is generated. S3. When a fault warning signal is received, the control unit performs automatic bypass or switching operation according to the fault module number, disconnecting the main module and connecting the backup module, or bypassing the affected sub-module and performing output power derating control. S4. After the switch is completed, the system operating parameters are re-monitored. When each parameter recovers to the static safety threshold range and runs stably for a set time, the redundant operation state is maintained or the main module operation is restored after manual confirmation. S5. Record fault warning signals, switching times, module numbers, and changes in operating parameters to the control system log, and upload them to the wind farm monitoring platform via the communication interface.

[0005] More preferably, the wind turbine converter includes a machine-side converter and a grid-side converter, both of which are equipped with independent redundant sub-modules, and the output terminal of the machine-side converter is connected to the input terminal of the grid-side converter via a parallel structure.

[0006] More preferably, the switching of the redundant modules is achieved through a fast electronic switch or relay, and the switching time is less than 10 ms, so as to ensure the continuity of the converter output voltage and current.

[0007] More preferably, the static safety threshold range is determined based on the equipment's factory test data or long-term operating statistics, and the parameters can be corrected through the control interface during the system debugging phase.

[0008] More preferably, the control unit performs multiple checks and confirmations on the fault signal before executing the redundant module switching. The switching command is only executed when the detection results exceed the threshold three times in a row, so as to avoid malfunctions caused by transient disturbances.

[0009] More preferably, the temperature detection signal of the power device is acquired by a thermistor, and the cooling flow signal is acquired by a flow sensor. The two are transmitted to the control unit for real-time comparison through an A / D conversion module.

[0010] More preferably, the output power derating control includes limiting the DC bus current of the converter or reducing the pulse width modulation duty cycle.

[0011] More preferably, the information record includes: Fault type, warning trigger time, switching completion time, bypassed module number, and power output status after switching.

[0012] More preferably, the communication interface communicates with the wind farm monitoring platform via a fiber optic network or a CAN bus.

[0013] More preferably, the method is applicable to a modular multilevel converter structure, wherein the redundant module is a pluggable power unit, and each power unit is independently configured with a control drive circuit and a cooling channel.

[0014] The embodiments of the present invention have the following advantages due to the adoption of the above technical solutions: I. This invention establishes a static threshold detection mechanism to continuously collect and compare key parameters of the converter, such as DC bus voltage, current, power device temperature, cooling flow rate, bus capacitor voltage drift, and device leakage current. When any parameter approaches or exceeds the safety threshold, the system immediately generates a fault warning signal. This can identify potential risks in the early stages of equipment performance degradation or cooling efficiency decline, enabling real-time monitoring and proactive warning of fault trends. This avoids sudden tripping or forced shutdown due to detection lag, thereby improving the safety and stability of wind turbine operation.

[0015] Second, this invention enables automatic bypass and module switching control in the converter system through the control unit. When a faulty module is determined to be abnormal, the system can automatically disconnect the main module and connect the backup module within milliseconds, or perform output power derating operation for minor abnormalities to ensure the continuity of energy transmission and the stable operation of the system. After the switching is completed, the system can maintain the redundant state after the parameters return to normal or reconnect the main module with manual confirmation. This realizes a fully automatic closed-loop control process from fault detection to switching to recovery, which greatly reduces the time for manual intervention and improves the operating availability and power generation efficiency of wind turbine units.

[0016] The above overview is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the invention will become readily apparent from the accompanying drawings and the following detailed description. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart of the steps of the present invention. Detailed Implementation

[0019] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0020] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0021] like Figure 1As shown, this embodiment of the invention provides a converter fault early warning and self-recovery control method for wind power systems, including the following steps: S1. During the operation of the wind turbine, the monitoring module collects key operating parameters of the converter in real time, including DC bus voltage, current, power device temperature, cooling flow rate, bus capacitor voltage deviation, and power device leakage current. The bus voltage and current signals are obtained by sensor sampling, the power device temperature is measured by thermistors attached to the surface of the heat sink, the cooling flow rate is detected by a flow sensor, the bus capacitor voltage deviation is obtained by voltage divider sampling, and the device leakage current signal is collected by the isolation detection module. All signals are filtered and converted by A / D before being input to the control unit for data processing. The control unit sets the upper and lower limits of the static safety threshold for each parameter based on the equipment's factory test data and long-term operation statistics. These thresholds can be corrected through the human-machine interface during the system debugging phase.

[0022] S2. The control unit continuously compares and calculates the real-time monitoring value with the static safety threshold range. When any parameter is detected to exceed the upper limit of the threshold, fall below the lower limit of the threshold, or have a rate of change exceeding the set range, the system initially determines that there is a potential abnormality and generates a fault warning signal. To prevent false alarms caused by transient disturbances or electromagnetic noise, the control unit is equipped with a multi-judgment mechanism: The signal is considered a valid fault warning signal only when three consecutive test results exceed the threshold and remain there for a duration exceeding the predetermined period. This determination ensures the stability and accuracy of the warning process.

[0023] S3. Upon receiving a valid fault warning signal, the control unit immediately performs automatic bypass or switching operations based on the fault module number to ensure continuous power output from the system and prevent fault propagation. For converters with a modular structure, the control unit drives a fast electronic switch or high-speed relay to disconnect the faulty submodule from the main power circuit and simultaneously connect the backup module. If it is a single-power module redundant structure, the main module is directly disconnected and the standby module is driven to be connected in parallel. To ensure a smooth switching, the control unit performs synchronous verification on the bus voltage and phase current of the standby module before switching to keep it in phase with the main module, and then completes the parallel connection operation. The entire switching process is completed within 10 milliseconds, ensuring the continuity of output voltage and current. When a fault is detected as a slight over-temperature or local current deviation, the control unit does not immediately switch modules, but instead executes power derating control. This reduces the thermal stress on power devices by limiting the DC bus current or reducing the pulse width modulation duty cycle, allowing the system to maintain operation in a safe state until the temperature or current returns to normal.

[0024] S4. After the redundant module switching is completed, the control unit continues to monitor the system's operating status in real time. When it is detected that all operating parameters have returned to the static safety threshold range and have been running stably for a set time window (e.g., 10 minutes), the system continues to generate electricity in the redundant operating state. If the on-site maintenance personnel confirm through the maintenance terminal that the faulty module has been repaired or replaced, they can manually control the system to reconnect the main module to the main circuit, thereby restoring the standard operating mode. During the above process, the system will automatically detect the voltage and current synchronization between the main and backup modules to ensure the smoothness and safety of the reconnection process. For systems with multiple redundant modules, the control unit can also dynamically balance the working power of each module according to the load distribution algorithm, so that the heat load of each power unit tends to be balanced, thereby extending the service life of the whole machine and maintaining stable operating efficiency.

[0025] S5. During the entire process of early warning and self-recovery, the control unit automatically records key operating information such as fault type, early warning trigger time, switching completion time, bypassed module number, and power output status after switching, and stores the recorded data in the system's non-volatile memory. The system interacts with the wind farm monitoring platform through a fiber optic communication network or CAN bus to realize fault alarm, operating status reporting, and maintenance task distribution functions. When the monitoring platform receives the fault record, it can display the current unit status in real time and prompt the operation and maintenance personnel to carry out targeted inspections or maintenance.

[0026] Workflow: When the wind turbine is running normally, the control system monitors the temperature, current, and cooling flow signals of each module in real time. If a module's heat dissipation is poor due to blockage in the cooling system or increased ambient temperature, and its temperature exceeds the set threshold of 90°C three times consecutively, the control unit immediately determines that the module is at risk of overheating and issues a fault warning signal. The system then performs an automatic bypass operation, quickly closing the switch to complete the switching between the main and backup modules. The backup module takes over the power output, and the entire process lasts no more than 10 milliseconds, ensuring uninterrupted power output from the turbine. After the switch, the control unit continues to monitor temperature changes. Once the temperature returns to normal and operates stably for a period of time, the system maintains a redundant operating state. If on-site maintenance personnel confirm that the original module's heat dissipation has returned to normal, they can reconnect the main module via the maintenance interface, and the system returns to its original operating mode. The entire warning, switching, and recovery process is automatically recorded and uploaded to the monitoring platform, enabling early detection, rapid response, and automatic recovery of converter faults.

[0027] In summary, this invention establishes a static threshold detection mechanism and hardware redundancy switching control logic to realize fault early warning and self-recovery functions for wind power system converters. Compared with traditional solutions that rely on manual inspection or shutdown maintenance, this invention can achieve automatic response and continuous power supply in the early stage of a fault, greatly improving the operational reliability, grid connection stability and maintenance efficiency of wind turbine units. It is applicable to various turbine-side or grid-side converter systems and can achieve modular integration and widespread application without changing the existing main control architecture.

[0028] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in the present invention, and these should all be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A converter fault early warning and self-recovery control method for wind power systems, characterized in that, Includes the following steps: S1. Real-time acquisition of key operating parameters of wind turbine converter, including DC bus voltage, current, power device temperature, cooling flow rate, bus capacitor voltage deviation and device leakage current, and setting static safety threshold ranges for each parameter. S2. The control system continuously compares the real-time monitoring value with the static safety threshold range. When any parameter exceeds the threshold or its rate of change exceeds the set range, a fault warning signal is generated. S3. When a fault warning signal is received, the control unit performs an automatic bypass or switching operation according to the fault module number, which disconnects the main module and connects the backup module, or bypasses the affected sub-module and performs output power derating control. The backup module is electrically connected to the main module and can be controlled independently. S4. After the switch is completed, the system operating parameters are re-monitored. When each parameter recovers to the static safety threshold range and runs stably for a set time, the redundant operation state is maintained or the main module operation is restored after manual confirmation. S5. Record fault warning signals, switching times, module numbers, and changes in operating parameters to the control system log, and upload them to the wind farm monitoring platform via the communication interface.

2. The converter fault early warning and self-recovery control method for wind power systems according to claim 1, characterized in that: The wind turbine converter includes a machine-side converter and a grid-side converter, both of which are equipped with bypassable redundant sub-modules, and the output terminal of the machine-side converter is connected to the input terminal of the grid-side converter via a parallel structure.

3. The converter fault early warning and self-recovery control method for wind power systems according to claim 1, characterized in that: The switching of redundant modules is achieved through fast electronic switches or relays, with a switching time of less than 10 ms, to ensure the continuity of the converter's output voltage and current.

4. The converter fault early warning and self-recovery control method for wind power systems according to claim 1, characterized in that: The static safety threshold range is determined based on the equipment's factory test data or long-term operating statistics, and the parameters can be corrected through the control interface during the system debugging phase.

5. The converter fault early warning and self-recovery control method for wind power systems according to claim 1, characterized in that: Before switching redundant modules, the control unit performs multiple checks and confirmations on the fault signal. The switching command is only executed when the detection results exceed the threshold three times in a row, so as to avoid malfunctions caused by transient disturbances.

6. The converter fault early warning and self-recovery control method for wind power systems according to claim 1, characterized in that: The temperature detection signal of the power device is acquired by a thermistor, and the cooling flow signal is acquired by a flow sensor. The two signals are transmitted to the control unit for real-time comparison via an A / D conversion module.

7. The converter fault early warning and self-recovery control method for wind power systems according to claim 1, characterized in that: The output power derating control includes limiting the DC bus current of the converter or reducing the pulse width modulation duty cycle.

8. The converter fault early warning and self-recovery control method for wind power systems according to claim 1, characterized in that: The information records include: Fault type, warning trigger time, switching completion time, bypassed module number, and power output status after switching.

9. The converter fault early warning and self-recovery control method for wind power systems according to claim 1, characterized in that: The communication interface communicates with the wind farm monitoring platform via a fiber optic network or CAN bus.

10. A converter fault early warning and self-recovery control method for wind power systems according to claim 1, characterized in that: The method is applicable to modular multilevel converter structures, where the redundant modules are pluggable power units, and each power unit is independently configured with control drive circuits and cooling channels.

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