Co-operative Current Ripple Reduction Strategy for Three-Phase Inverter With Flexible Zero Vector Redistribution

In traditional space vector pulse width modulation scheme, the duration of zero vector (vector 0, vector 7) is equally divided. On this occasion, the corresponding control freedom is wasted, since the zero vector distribution exerts an influence on the current ripple without affecting the total voltage vector synthesis. Accordingly, this article proposes a novel co-operative current ripple reduction strategy based on zero vector redistribution for the typical two-level three-phase inverters. In the proposed strategy, the three-phase current ripple condition is classified into three cases according to the current ripple change rate and the duty cycle of each phase. In each case, the corresponding optimization method of zero vector distribution is derived and performed, such as only using vector 0, only using vector 7, or flexibly distributing vectors 0 and 7. With the proposed strategy, the three-phase current ripples are reduced co-operatively and effectively. Moreover, the proposed strategy also possesses the advantage of lower switching losses. This is because vector 0 or 7 is eliminated in partial regions of the space hexagon, resulting in a reduction in the number of switching actions. Finally, the simulation and experimental verifications are performed to validate the effectiveness of the proposed strategy.