Analysis and Implementation of a Simplified Optimized Space Vector Modulation Strategy for Multilevel Inverter Based on the Equivalent Inverter

This paper presents a simplified space vector pulse width modulation (SVPWM) strategy with the optimized switching sequence for multilevel inverter. An n-level inverter will be equivalent to n-1 two-level inverters using the proposed concept of the equivalent inverter. Through the redistribution of the space vector plane and the establishment of vector decomposition rules, the space vector plane and reference voltage will be simplified to n-1 two-level planes and n-1 two-level reference voltages to make the control of the multilevel system come to resynthesize the original reference voltage and modulate the n-1 equivalent two-level inverters. Therefore, the multilevel SVPWM with high complexity can be accomplished briefly by the two-level SVPWM method. Besides, this modulation strategy can achieve the optimized switching sequence with the common way of determining the two-level switching sequence. Simulations and experiments will be used to verify its validity and the realization of all functions in the whole system is accomplished by the digital signal processor.