Abstract：Contrastive analysis of zero-sequence voltage injected SPWM and SVPWM is made in this paper, and the relationship between the two modulation strategies in duty ratio and vector sequences is explained with line voltage based space vector diagram and switching period window shift diagram. On the basis of inherent consistency between the two modulation strategies, a three-level pulse width modulation scheme based on zero-sequence voltage injection and modulation-waves decomposition is discussed in this paper. Complex space vector resolution, which is necessary in SVPWM, is completely eliminated in this PWM scheme. The control objectives such as minimum switching loss, optimal output voltage quality or neutral point balancing control can be alternatively achieved and smoothly transformed into each other. Therefore, the proposed PWM scheme is extremely flexible and easy to realize. The program difficulty and computation time can be greatly reduced.
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2014, Vol. 29 
