Four Switches Three Phase Inverter Space Vector Overmodulation Analysis

the four-switch three-phase inverter FSTPI) topology can be regarded as a fault-tolerant solution for six-switch three-phase machine drive systems. This configuration reduces cost, complexity, and switching losses while maintaining acceptable performance for certain applications. In this configuration, one phase is connected to the midpoint of two series-connected capacitors or battery on the DC-link. The voltage vectors composes of only two long voltage vectors and two short voltage vectors. Because of half voltage utilization, the maximum speed for the motor is reduced to half. In this paper, overmodulation strategies for a FSTPI enhance the output voltage capability beyond the linear modulation range has been proposed, which targets at improving DC bus utilization while maintaining acceptable harmonic performance. Simulation results validate the effectiveness of the proposed methods, demonstrating improved voltage gain and stability under overmodulation conditions.