An Improved Fault-Tolerant Control Strategy for High-Power ANPC Three-Level Inverter Under Short-Circuit Fault of Power Devices

The high-power active neutral-point clamped (ANPC) three-level inverter has high-reliability requirements for the system operation, and short-circuit fault, very common, and serious problem in the operation will affect the operation stability. To solve this problem, the fault current path analyses under a single device and multi-device short-circuit fault were carried out first in this paper. Second, on the basis of the different fault condition, an improved fault-tolerant control strategy was proposed. This strategy maintains the three-level operation under a single device short-circuit fault, and under multiple device, fault operates with low withstanding voltage. Finally, the experiment was made on a 1 MW ANPC three-level platform, which proved the effectiveness of the proposed method.