Virtual Vector based SVPWM-DTC for Five-Phase Two-Level VSI fed Induction Motor Drive

A five-phase two-level voltage source inverter (FPTL-VSI) fed five-phase induction motor (FPIM) drive is considered here for the analysis. FPTL- VSI produces higher common mode voltage, which cannot be completely eliminated but can be reduced with proper selection of voltage vectors. In this paper, a space vector pulse width modulation (SVPWM) based direct torque control (DTC) scheme is implemented to achieve reduced CMV with enhanced speed and torque control at constant switching frequency. An 80% CMV reduction in comparison to its peak-to-peak value is achieved using the proposed SVPWM-DTC scheme. In addition, a volt-second balancing method is proposed to analyse the effect of SVPWM resultant voltage vector on motor drive speed and torque response over a wide range of modulation index. A high-power laboratory prototype of FPIM drive is used to validate the proposed SVPWM-DTC scheme under steady-state and dynamic conditions over a wide range of speed variations. Through assessing the effectiveness of CMV and the switching frequency, the efficacy of the proposed SVPWM-DTC is compared with the existing literature.