A Novel Space Vector PWM Scheme for Multilevel Inverters

This paper proposes a generalized method for the generation of space vector pulse width modulation (SVPWM) signals for multilevel inverters. The objective of the proposed method is to eliminate the need of lookup table and sector identification required in the implementation of SVPWM for multilevel inverters. In the proposed method, the actual sector containing the tip of the reference space vector is not identified. A novel method based on the principle of mapping is presented for the automatic generation of the switching vectors associated with the sectors of multilevel inverter. The center of subhexagon containing the actual reference vector is identified by a new technique proposed in this paper. Using the subhexagon center, the reference vector is mapped to 2-level space vector diagram and the switching vectors of the 2-level inverter are determined. These switching vectors are translated to the required switching vectors of the multilevel inverter by proposed method of reverse mapping. The proposed method can be extended to any n-level inverter. The scheme is explained for a 5-level inverter and experimental results are presented for a 3-level inverter.