Improved pulse -width modulation of diode-assisted buck-boost voltage source inverter

This paper explorers modulation strategies for diode-assisted buck-boost voltage source inverter and the relationship of voltage transfer ratio versus modulation index. Two kinds of improved pulse-width modulation strategies with high dc link voltage utilization are presented to obtain maximum voltage gain at given modulation index and minimize the voltage stress at the same time. The operation principle and realization of the proposed modulation strategies, the relationship of voltage gain versus modulation index and voltage stress versus voltage gain are analyzed in details. Simulation results are given to verify the theoretical analysis and demonstrate good performance of the improved pulse width modulation strategies.