Flexible direct current transmission converter valve and IGBT and trigger circuit fault detection method thereof

Abstract

The present application relates to the technical field of high-voltage direct current transmission, in particular to a flexible direct current transmission converter valve and an IGBT and trigger loop fault detection method thereof. The present application is based on a flexible direct current transmission converter valve, generates submodule control instructions through a valve control system and sends them to a submodule controller, processes the received submodule control instructions to generate processed control instructions and transmits them to the valve control system and the submodule, collects the capacitor voltage of the submodule and the output voltage of the submodule, then uses the processed control instructions to detect the submodule controller, and uses the capacitor voltage of the submodule and the output voltage of the submodule to detect the submodule. The whole detection process of the present application realizes the detection of the submodule controller and the submodule on the link at the same time, makes the fault detection on the link more comprehensive, improves the efficiency of fault detection, and can realize real-time online detection, thereby improving the timeliness of fault detection.

Description

Technical Field

[0001] This invention relates to the field of high voltage direct current (HVDC) transmission technology, and in particular to a flexible HVDC converter valve and a fault detection method for its IGBT and trigger circuit. Background Technology

[0002] In the operation of MMC-based flexible DC transmission projects, each bridge arm is often composed of hundreds of sub-modules connected in series. Each sub-module contains multiple IGBTs, and each IGBT corresponds to a trigger circuit. Therefore, the number of IGBT trigger circuits in the MMC converter valve is very large. As the commands issued by the valve control system to the controllers of each sub-module change, the switching state of each sub-module also changes accordingly. During the switching state transition, link state switching failures can easily occur.

[0003] For detecting the cause of link state switching failure, existing technologies can detect communication faults in the link in flexible DC engineering. However, in many cases, the link failure is not caused by communication failures between the various devices on the link, but by faults in the devices themselves, such as failure to execute instructions correctly or unstable operation. Currently, only single devices on the link are detected for faults, and multiple devices on the link are not detected for faults at the same time, resulting in incomplete and inefficient detection of link faults in flexible DC engineering. Summary of the Invention

[0004] The purpose of this invention is to provide a flexible DC transmission converter valve to solve the problems of incomplete and inefficient detection of link faults in the existing flexible DC transmission engineering; it also provides a fault detection method for the IGBT and its trigger circuit in the flexible DC transmission converter valve, which can realize the fault detection process of the IGBT and its trigger circuit in the above-mentioned converter valve.

[0005] To solve the above-mentioned technical problems, the present invention provides a flexible DC transmission converter valve, the specific steps of which are as follows:

[0006] The valve control system generates submodule control commands and sends them to the submodule controller. The submodule controller processes the received submodule control commands, generates processed control commands, and then uploads the processed control commands to the valve control system and sends them to the submodules.

[0007] The submodule executes the received processed control commands, and the submodule controller collects the submodule capacitor voltage and the submodule output voltage, and uploads them to the valve control system.

[0008] The valve control system determines whether the communication link of the submodule controller is faulty based on the received and processed control commands, and determines whether the submodule IGBT is faulty based on the submodule capacitor voltage, submodule output voltage, control commands and current direction uploaded by the submodule controller.

[0009] Beneficial Effects: This invention, based on a flexible DC transmission converter valve, generates submodule control commands through a valve control system and sends them to the submodule controller. The submodule controller processes the received submodule control commands to generate processed control commands, which are then transmitted to the valve control system and the submodule. The invention also collects the submodule capacitor voltage and the submodule output voltage. The processed control commands are then used to detect the submodule controller, and the capacitor voltage and output voltage are used to detect the submodule itself. Therefore, the entire detection process simultaneously detects both the submodule controller and the submodule on the link, resulting in more comprehensive fault detection, improved fault detection efficiency, and real-time online detection, thus enhancing the timeliness of fault detection.

[0010] Furthermore, the valve control system determines whether the submodule controller is faulty based on whether the generated submodule control command is consistent with the received processed control command.

[0011] Beneficial effects: This invention can detect the submodule controller simply by comparing the submodule control command generated by the valve control system with the received processed control command, and the detection process is convenient and quick.

[0012] Furthermore, if the submodule controller is not faulty, the valve control system determines whether the submodule IGBT is faulty by comparing the submodule capacitor voltage and submodule output voltage corresponding to the generated submodule control command with the submodule capacitor voltage and submodule output voltage received from the submodule controller.

[0013] Beneficial effects: When the submodule controller is not faulty, this invention can also detect the submodule IGBT by simply comparing the submodule capacitor voltage and submodule output voltage corresponding to the submodule control command generated by the valve control system with the submodule capacitor voltage and submodule output voltage uploaded by the submodule controller. The detection process is convenient and quick.

[0014] Furthermore, if the submodule controller malfunctions, the valve control system determines whether the submodule IGBT is faulty by comparing the submodule capacitor voltage and submodule output voltage corresponding to the received processed control command with the submodule capacitor voltage and submodule output voltage uploaded by the submodule controller.

[0015] Beneficial effects: Even when the submodule controller is faulty, this invention can still detect the submodule IGBT by comparing the submodule capacitor voltage and submodule output voltage corresponding to the processed control command received by the valve control system with the submodule capacitor voltage and submodule output voltage uploaded by the submodule controller. In other words, the detection of the submodule IGBT is not affected by the submodule controller failure, thus improving the robustness of the submodule IGBT detection.

[0016] Furthermore, the submodule control commands are generated based on the modulation wave, the submodule current direction, the submodule capacitor voltage, and the submodule output voltage.

[0017] Beneficial effects: The valve control system generates submodule control commands based on the current modulation wave, submodule current direction, submodule capacitor voltage, and submodule real-time voltage. This enables the generated submodule control commands to better match the current operating conditions and also serves to detect the link's operating status.

[0018] The present invention also provides a flexible DC transmission converter valve, including a valve control system, a submodule controller and a submodule, and further including a submodule current measurement system and a submodule voltage measurement system. The submodule current measurement system is used to connect to the valve control system to measure the submodule current and upload it to the valve control system; the submodule voltage measurement system is used to connect to the submodule controller.

[0019] The valve control system generates submodule control commands and sends them to the submodule controller. Based on the received and processed control commands, it determines whether the communication link of the submodule controller is faulty. Based on the submodule capacitor voltage, submodule output voltage, control commands, and current direction uploaded by the submodule controller, it determines whether the submodule IGBT is faulty.

[0020] The submodule controller processes the received submodule control commands, generates processed control commands, and then uploads the generated processed control commands to the valve control system and sends them to the submodules respectively.

[0021] The submodule executes the received control commands. The submodule voltage test system collects the submodule capacitor voltage and the submodule output voltage through the submodule controller and uploads them to the valve control system.

[0022] Beneficial Effects: This invention, based on a flexible DC transmission converter valve, generates submodule control commands through a valve control system and sends them to the submodule controller. The submodule controller processes the received submodule control commands to generate processed control commands, which are then transmitted to the valve control system and the submodule. The invention also collects the submodule capacitor voltage and the submodule output voltage. The processed control commands are then used to detect the submodule controller, and the capacitor voltage and output voltage are used to detect the submodule itself. Therefore, the entire detection process simultaneously detects both the submodule controller and the submodule on the link, resulting in more comprehensive fault detection, improved fault detection efficiency, and real-time online detection, thus enhancing the timeliness of fault detection.

[0023] Furthermore, the valve control system determines whether the submodule controller is faulty based on whether the generated submodule control command is consistent with the received processed control command.

[0024] Beneficial effects: This invention can detect the submodule controller simply by comparing the submodule control command generated by the valve control system with the received processed control command, and the detection process is convenient and quick.

[0025] Furthermore, if the submodule controller is not faulty, the valve control system determines whether the submodule IGBT is faulty by comparing the submodule capacitor voltage and submodule output voltage corresponding to the generated submodule control command with the submodule capacitor voltage and submodule output voltage received from the submodule controller.

[0026] Beneficial effects: When the submodule controller is not faulty, this invention can also detect the submodule IGBT by simply comparing the submodule capacitor voltage and submodule output voltage corresponding to the submodule control command generated by the valve control system with the submodule capacitor voltage and submodule output voltage uploaded by the submodule controller. The detection process is convenient and quick.

[0027] Furthermore, if the submodule controller malfunctions, the valve control system determines whether the submodule IGBT is faulty by comparing the submodule capacitor voltage and submodule output voltage corresponding to the received processed control command with the submodule capacitor voltage and submodule output voltage uploaded by the submodule controller.

[0028] Beneficial effects: Even when the submodule controller is faulty, this invention can still detect the submodule IGBT by comparing the submodule capacitor voltage and submodule output voltage corresponding to the processed control command received by the valve control system with the submodule capacitor voltage and submodule output voltage uploaded by the submodule controller. In other words, the detection of the submodule IGBT is not affected by the submodule controller failure, thus improving the robustness of the submodule IGBT detection.

[0029] Furthermore, the submodule control commands are generated based on the modulation wave, the submodule current direction, the submodule capacitor voltage, and the submodule output voltage.

[0030] Beneficial effects: The valve control system generates submodule control commands based on the current modulation wave, submodule current direction, submodule capacitor voltage, and submodule real-time voltage. This enables the generated submodule control commands to better match the current operating conditions and also serves to detect the link's operating status. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the flexible DC power transmission converter valve of the present invention;

[0032] Figure 2 This is a schematic diagram of the MMC flexible DC transmission converter valve half-bridge module;

[0033] Figure 3 This is the schematic diagram of the MMC flexible DC transmission converter valve full-bridge submodule. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical principles and practical applications of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0035] Example of a flexible DC power transmission converter valve:

[0036] This invention is based on a flexible DC transmission converter valve. A valve control system generates submodule control commands and sends them to the submodule controller. The submodule controller processes the received control commands, generates processed control commands, and transmits them to both the valve control system and the submodule. It also collects the submodule capacitor voltage and output voltage. The processed control commands are then used to detect the submodule controller, and the capacitor and output voltages are used to detect the submodule itself. Therefore, the entire detection process simultaneously detects both the submodule controller and the submodule on the link, resulting in more comprehensive fault detection, improved efficiency, and real-time online detection, thus enhancing the timeliness of fault detection.

[0037] This embodiment uses a flexible DC transmission converter valve based on MMC as an example for illustration. A schematic diagram of the converter valve's structure is shown below. Figure 1 As shown, it consists of a valve control system, a submodule controller, a submodule, a submodule current measurement system, and a submodule voltage test system. The valve control system, the submodule controller, and the submodule are connected in sequence, the submodule current measurement system is connected to the valve control system, and the submodule voltage test system is connected to the submodule controller.

[0038] The submodule includes two IGBT devices and S1 and S2 drivers for controlling them respectively. The S1 driver controls the S1 switch to turn on or off, and the S2 driver controls the S2 switch to turn on or off. The valve control system sends control commands to the submodule controller, which processes these commands and then uploads them to the valve control system and sends them back to the submodule. The submodule executes the control commands issued by the submodule controller. The submodule voltage testing system collects the submodule capacitor voltage U1 and the submodule output voltage Us2 (i.e., the voltage between node 1 and node 2 in the submodule, where the positions of node 1 and node 2 are as follows) through the submodule controller. Figure 1 (As shown), and the two voltages are uploaded to the valve control system through the submodule controller; the submodule current measurement system measures the submodule current Iarm through the valve control system.

[0039] At this point, the valve control system includes its own generated submodule control commands, processed control commands uploaded by the submodule controller, submodule capacitor voltage U1, submodule output voltage Us2, and submodule current Iarm, among other information. Based on this information, the submodule control commands generated by the valve control system, along with the corresponding submodule capacitor voltage and submodule output voltage, are as follows: When an activation command is issued, S1 is on and S2 is off, and Us2 and U1 are the same; when a deactivation command is issued, S1 is off and S2 is on, and Us2 voltage is 0.

[0040] Therefore, based on the structure and function of the flexible DC transmission converter valve, a fault detection method for the IGBT and its trigger circuit of the converter valve was developed. First, the valve control system generates submodule control commands and sends them to the submodule controller. The submodule controller processes the received submodule control commands and generates processed control commands. The specific processing steps are as follows: if the submodule controller does not detect a fault, it executes the submodule control commands received from the valve control system; if the submodule controller detects an overvoltage fault, it turns on S2 and turns off S1; if the submodule controller detects other faults, it turns off S1 and S2, and uploads the generated processed control commands to the valve control system and sends them to the submodules respectively. Then, the submodule executes the received processed control commands. The submodule controller collects the submodule capacitor voltage and the submodule output voltage and uploads them to the valve control system. Finally, the valve control system determines whether the communication link of the submodule controller is faulty based on the received processed control commands, and determines whether the submodule IGBT is faulty based on the submodule capacitor voltage, submodule output voltage, control commands, and current direction uploaded by the submodule controller. The specific process is as follows:

[0041] The valve control system generates submodule control commands based on the modulation wave, submodule current direction, submodule capacitor voltage, and submodule output voltage. These commands include, for example, enabling (S1 on, S2 off) or disabling (S2 on, S1 off) commands. The generated submodule control commands are then sent to the submodule controller. The submodule controller processes the received submodule control commands to generate processed control commands, which are then uploaded to the valve control system and sent to the submodules. Upon receiving the processed control commands, the submodules execute the IGBT on or off actions. Finally, the submodule controller collects the submodule capacitor voltage and submodule output voltage and uploads them to the valve control system.

[0042] The valve control system compares the generated submodule control command with the received processed control command to determine if the submodule controller is faulty. If the submodule control command matches the processed control command, the submodule controller is functioning normally; otherwise, the submodule controller is faulty.

[0043] If the submodule controller is functioning correctly, the valve control system compares the submodule capacitor voltage and output voltage corresponding to the generated submodule control command with the received submodule capacitor voltage and output voltage uploaded by the submodule controller to determine if the submodule IGBT is faulty. If the submodule capacitor voltage corresponding to the generated submodule control command matches the submodule capacitor voltage uploaded by the submodule controller, and the output voltage corresponding to the generated submodule control command also matches the submodule output voltage uploaded by the submodule controller, then the submodule IGBT is functioning correctly; otherwise, the submodule IGBT is faulty.

[0044] If the submodule controller malfunctions, the valve control system compares the submodule capacitor voltage and output voltage corresponding to the received processed control command with the submodule capacitor voltage and output voltage uploaded by the submodule controller to determine if the submodule IGBT is faulty. If the submodule capacitor voltage corresponding to the processed control command matches the submodule capacitor voltage uploaded by the submodule controller, and the submodule output voltage corresponding to the processed control command also matches the submodule output voltage uploaded by the submodule controller, then the submodule IGBT is normal; otherwise, the submodule IGBT is faulty.

[0045] For example, for a normally conducting submodule, if the submodule current Iarm flows from above node 1, then through the diode and capacitor corresponding to the IGBT connected to driver S1, and flows to node 2, that is, S1 is on and S2 is off, the capacitor can be charged normally, so the submodule's output voltage Us2 = U1 ≠ 0; if the submodule current Iarm flows from node 2, then through the diode corresponding to the IGBT connected to driver S2, and flows out from node 1, that is, S1 is off and S2 is on, the capacitor cannot be charged, so the submodule's output voltage Us2 = 0, U1 ≠ 0.

[0046] If the valve control system issues an activation command, i.e., S1 is turned on and S2 is turned off, then the output voltage Us2 of the submodule corresponding to this command and the capacitor voltage U1 of the submodule are the same, i.e., Us2 = U1 ≠ 0. The submodule controller processes the received activation command from the valve control system and generates a processed control command, which is then uploaded to the valve control system and sent to the submodule. If the processed control command is the same as the issued activation command, it indicates that the submodule controller is functioning normally; otherwise, it indicates that the submodule controller is faulty.

[0047] When the submodule controller is normal, if the collected submodule capacitor voltage and submodule output voltage are equal to the submodule capacitor voltage and submodule output voltage corresponding to the submodule control command, then the submodule is normal; if Us2=0 or U1=0, then the submodule is faulty.

[0048] When the submodule controller malfunctions and the output voltage of the submodule corresponding to the processed control command generated by the submodule controller is 0, if the sampled output voltage of the submodule is 0 and the sampled submodule capacitor voltage is equal to the submodule capacitor voltage corresponding to the processed control command generated by the submodule controller, then the submodule is normal; otherwise, the submodule is faulty.

[0049] Each MMC flexible DC transmission converter valve submodule can adopt, for example... Figure 2 The half-bridge structure submodule shown can also be adopted as follows: Figure 3 The full-bridge structure submodule is shown. The choice of submodule structure is not limited to the two submodule structures mentioned above, but also includes various other rectifier modules and corresponding modified structures in the prior art.

[0050] The fault detection method in this embodiment is illustrated by taking the detection of a sub-module and its control system as an example. As other implementation methods, it can be used to detect multiple sub-modules according to actual needs. The settings and working methods of each sub-module are similar.

[0051] Example of a fault detection method for flexible DC transmission converter valve IGBT and its trigger circuit:

[0052] The fault detection method for the flexible DC transmission converter valve IGBT and its trigger circuit in this embodiment has been described in detail in the above-described flexible DC transmission converter valve embodiment, and will not be repeated here.

Claims

1. A method for fault detection of a flexible DC transmission converter valve IGBT and its trigger circuit, characterized in that, The specific steps are as follows: The valve control system generates submodule control commands and sends them to the submodule controller. The submodule controller processes the received submodule control commands, generates processed control commands, and uploads the processed control commands to the valve control system and sends them to the submodules. The specific processing steps are as follows: if the submodule controller does not detect a fault, it executes the submodule control commands received from the valve control system; if the submodule controller detects an overvoltage fault, it turns on S2 and turns off S1, i.e., disconnects the submodule; if the submodule controller detects other faults, it turns off S1 and S2, where S1 and S2 are two IGBT devices in the submodule. The submodule executes the received processed control commands, and the submodule controller collects the submodule capacitor voltage and the submodule output voltage, and uploads them to the valve control system. The valve control system determines whether the communication link of the submodule controller is faulty based on the received and processed control commands, and determines whether the submodule IGBT is faulty based on the submodule capacitor voltage, submodule output voltage, control commands and current direction uploaded by the submodule controller.

2. The method for fault detection of the flexible DC transmission converter valve IGBT and its trigger circuit according to claim 1, characterized in that, The valve control system determines whether the submodule controller is faulty based on whether the generated submodule control command is consistent with the received processed control command.

3. The method for fault detection of the flexible DC transmission converter valve IGBT and its trigger circuit according to claim 2, characterized in that, If the submodule controller is not faulty, the valve control system determines whether the submodule IGBT is faulty based on whether the submodule capacitor voltage and submodule output voltage corresponding to the generated submodule control command are consistent with the submodule capacitor voltage and submodule output voltage received from the submodule controller.

4. The method for fault detection of the flexible DC transmission converter valve IGBT and its trigger circuit according to claim 2, characterized in that, If the submodule controller malfunctions, the valve control system determines whether the submodule IGBT is faulty by comparing the submodule capacitor voltage and submodule output voltage corresponding to the received processed control command with the submodule capacitor voltage and submodule output voltage uploaded by the submodule controller.

5. The method for fault detection of the flexible DC transmission converter valve IGBT and its trigger circuit according to any one of claims 1-4, characterized in that, The submodule control command is generated based on the modulation wave, the submodule current direction, the submodule capacitor voltage, and the submodule output voltage.

6. A flexible DC transmission converter valve, comprising a valve control system, a submodule controller, and a submodule, characterized in that, It also includes a submodule current measurement system and a submodule voltage measurement system. The submodule current measurement system is connected to the valve control system to measure the submodule current and upload it to the valve control system. The submodule voltage measurement system is connected to the submodule controller. The valve control system generates submodule control commands and sends them to the submodule controller. Based on the received processed control commands, it determines whether the communication link of the submodule controller is faulty. Based on the submodule capacitor voltage, submodule output voltage, control commands, and current direction uploaded by the submodule controller, it determines whether the submodule IGBT is faulty. The submodule controller processes the received submodule control commands, generates processed control commands, and uploads the processed control commands to the valve control system and sends them to the submodules. The specific processing procedure is as follows: if the submodule controller does not detect a fault, it executes the submodule control commands sent by the valve control system; if the submodule controller detects an overvoltage fault, it turns on S2 and turns off S1, i.e., disconnects the submodule; if the submodule controller detects other faults, it turns off S1 and S2, where S1 and S2 are two IGBT devices in the submodule. The submodule executes the received control commands, and the submodule voltage test system collects the submodule capacitor voltage and the submodule output voltage through the submodule controller and uploads them to the valve control system.

7. The flexible DC transmission converter valve according to claim 6, characterized in that, The valve control system determines whether the submodule controller is faulty based on whether the generated submodule control command is consistent with the received processed control command.

8. The flexible DC transmission converter valve according to claim 7, characterized in that, If the submodule controller is not faulty, the valve control system determines whether the submodule IGBT is faulty based on whether the submodule capacitor voltage and submodule output voltage corresponding to the generated submodule control command are consistent with the submodule capacitor voltage and submodule output voltage received from the submodule controller.

9. The flexible DC transmission converter valve according to claim 7, characterized in that, If the submodule controller malfunctions, the valve control system determines whether the submodule IGBT is faulty by comparing the submodule capacitor voltage and submodule output voltage corresponding to the received processed control command with the submodule capacitor voltage and submodule output voltage uploaded by the submodule controller.

10. The flexible DC transmission converter valve according to any one of claims 6-9, characterized in that, The submodule control command is generated based on the modulation wave, the submodule current direction, the submodule capacitor voltage, and the submodule output voltage.

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