A novel quasi-hot standby fault-tolerant control strategy for cascaded H-bridge rectifier

Cascaded H-bridge rectifier (CHBR) is widely used in high-power fields such as STATCOM and power electric traction transformer (PETT) due to its high efficiency and easy expandability. With the high-reliability operation requirements of power equipment, the fault-tolerance capability has gradually become a research hotspot nowadays. In order to improve the reliability of the power supply, cascaded H-bridge rectifier should restore as soon as possible after a fault. However, the traditional fault-tolerant strategies have a great effect on the grid side and a long recovery time. This paper proposed a quasi-hot standby fault-tolerant control strategy. Compared with the traditional strategies, the quasi-hot standby fault-tolerant control strategy has a faster recovery speed after the malfunction, and its transient recovery process has less impact on the power grid. Simulation and experiment results show the effectiveness and good recovery performance of the proposed fault-tolerant control strategy.