A New Fault-Tolerant Method for 5-Level Active Neutral Point Clamped Inverter Using Sinusoidal PWM

A new fault-tolerant method is presented in this paper for a 5-level active neutral point clamped inverter (ANPC) using a modified sinusoidal pulse width modulation (SPWM). The existing methods is based on space vector modulation (SVM) as voltage vectors have redundant switching states at low modulation index. The same concept is achieved by using the modified SPWM with the same performance compared to SVM. This method can achieve higher capability of fault-tolerance at certain faulty conditions which cannot be achieved by SVM. The proposed method is based on dividing the 5-level ANPC inverter into several sub-inverters with reduced levels. A modified modulating signal is used to control the sub-inverters. Matlab/Simulink is used to verify the proposed method for a 5-level ANPC inverter. Simulation results show that the system performance at fault-tolerance is the same as healthy conditions. The proposed method can be used for other types of multi-level inverters.