Equivalent Space Vector Output of Diode Clamped Multilevel Inverters through Modulation Wave Decomposition under Carrier-Based PWM Strategy

The carrier-based PWM method (CBPWM) and the space vector PWM method (SVPWM) are two main modulation methods for diode clamped multilevel converters, and there is a certain relationship between these two modulation strategies. For general 8 segments SVPWM modulation sequence in the multilevel inverter, the inherent relationship between these two modulation methods have been researched, but the relationship between CBPWM and SVPWM in an arbitrary level sequence has not been obtained. To solve this problem, an in-depth study of the relationship between the multilevel SVPWM method and the CBPWM method has been made in this paper. By decomposing the modulation wave, and the SVPWM can be achieved by multi-modulation waves CBPWM. And the relationship between SVPWM and CBPWM in N level with an arbitrary number of segments sequence are obtained. Thus, through simple multi-modulation waves CBPWM strategy, less THD in the spectrum and higher DC voltage utilization switching sequences of multilevel inverters can be obtained. The simulation and experimental results illustrate that the relationship between CBPWM and SVPMM is correct.