Condition Monitoring for IGBT Modules in VSC-VHDC Valves Based on Near-Field Electromagnetic Radiation

Large-capacity power electronic equipment is the core equipment for the integration of new energy and long-distance high-voltage direct current transmission. Whether it can operate reliably for a long time is related to the safety and stability of the VSC-VHDC. In this paper, in order to monitor the condition of the IGBT module in the converter valve, an IGBT monitoring system that can be installed inside the converter valve has been developed. A wide-band current sensing probe was designed based on the B-dot coil structure, with the maximum response frequency reaching up to 100 MHz. The sensor acquisition system includes a high-speed ADC acquisition module and an electro-optical conversion module. The sampling rate can reach 125 MHz. By connecting it to the central control board of the converter valve with optical fibers, the online transmission of sensor data is achieved, and the online monitoring of the electromagnetic radiation of the IGBT module is realized. The accuracy of the monitoring system was verified by building a double pulse test platform for measurement tests. The performance indicators such as frequency response characteristics met the research requirements. The online monitoring of the conditions of the IGBT module in VSC-VHDC valve was achieved, which is conducive to timely discovering the impact of abnormal conditions on the IGBT module and improving the operational stability of the converter valve.