Fault-tolerant operation of a 150 kW 3-level neutral-point clamped PWM inverter in a flywheel energy storage system

This paper proposes a fault-tolerant operation strategy of three-level neutral-point-clamped PWM inverters in high power, high performance, safety-critical applications. Likely faults are identified and fault-tolerant schemes based on the inherent redundancy of voltage vectors of neutral-point-clamped inverters are presented. Simulation verification is performed and shows good fault handling capability. A 150 kW neutral-point-clamped inverter is constructed for flywheel energy storage applications. Experimental testing of the fault-tolerant operation strategy is in progress.