蒲清昕,秦亮,王庆,刘开培.模块化多电平变流器子模块电容老化状态在线监测及均衡策略[J].电测与仪表,2022,59(7):193-200. Pu Qingxin,Qin Liang,Wang Qing,Liu Kaipei.On-line Monitoring and Balancing Strategy for Capacitor aging in Modular Multilevel Converter[J].Electrical Measurement & Instrumentation,2022,59(7):193-200.
模块化多电平变流器子模块电容老化状态在线监测及均衡策略
On-line Monitoring and Balancing Strategy for Capacitor aging in Modular Multilevel Converter
The more serious sub-module capacitor aging in the Modular Multilevel Converter (MMC) will increase the switching frequency and increase the loss of the converter valve, which will damage the safe operation of the inverter. Aiming at this problem, this paper proposes a capacitor aging state monitoring and balancing strategy for MMC. First, the capacitance aging state is monitored online by the relationship between the capacitance voltage change and the capacitance value, and the relative value between the sub-module capacitances is measured. Then, according to the measurement result, the virtual capacitor voltage is introduced in the sorting to reduce the switching frequency of the aging severe sub-module and delay the service life of the capacitor. The simulation results show that the proposed strategy can effectively reduce the switching frequency of the aging verification sub-module without affecting the capacitor voltage balance. This method does not need to add additional equipment to the sub-module, does not use complex algorithms, and can be applied in many occasions where there are many sub-modules.
