Improved SVPWM modulation method for three-phase dual-input dual-buck inverters

The traditional modulation method for three-phase dual-input dual-buck inverters is level-shifted sine pulse width modulation. The disadvantage of this method is that the dc voltage utilization ratio is low and the software fault tolerance is difficult to realize. To solve these problems, an improved SVPWM suitable for this inverter is proposed in this paper. By analyzing the switch modes and bridge arm midpoint level of this inverter, 27 voltage vectors are obtained. According to the obtained long vector cluster, medium vector cluster, and short vector cluster, six modulation sectors are obtained, and each modulation sector has four modulation regions. When the voltage of the inverter low-voltage dc source changes, the associated vector changes as well. How the modulation region changes when the associated vector changes is analyzed. The action time of each vector in each modulation region is deduced. In addition, the action order of each vector involved in vector synthesis is optimized. A 2 kW prototype was built to carry out experimental research. Experimental results show that this modulation method improves the dc voltage utilization ratio, reduces the loss, and improves the efficiency of the inverter.