Reduced switch count seventeen level inverter topology for open-end induction motor drives

This paper presents a seventeen level inverter topology for open end induction motor drives requiring only twelve switches per phase. One three-level inverter and one seven-level inverter with DC link voltages in 3:1 ratio are connected to the two ends of the stator winding of the induction motor to generate a seventeen level space vector structure. A level shifted carrier based scheme is used to modulate the inverter, which requires only instantaneous phase voltage references. Selection of switching states is used to ensure that both inverters supply real power to the motor the over entire modulation range, preventing overcharging of the DC bus. The topology was tested for steady state operation over the entire modulation range, and experimental results are included below.