Abstract: Conventional inverters require numerous DC voltage sources, switches and increased converter cost for high voltage applications. In high power and high voltage applications, the two level inverters have some limitations mainly due to switching losses, dv/dt and di/dt stresses and constraint of the semiconductor power device ratings. To overcome these issues multilevel inverters can be employed. Multilevel approach gives reduced stress on semiconductor switches, lower Total Harmonic Distortion (THD) at output, low switching losses, high voltage capability, and ease of control. Hence multilevel inverters are gaining more importance and detailed research and studies are still going on in this area. In this paper design and simulation results of single phase seven level, inverter fed induction motor drive is presented. The seven level output is obtained by an improved inverter topology with less number of circuit components and reduced output voltage THD. The multilevel inverter is controlled with phase disposition pulse width modulation. The simulation of single phase seven level inverter fed induction motor model is done by using MATLAB. The DC link capacitor voltage is balanced by using Resonant Switched Capacitor Converter (RSCC). From the simulation result it is observed that the output waveforms are better than that of a conventional inverter fed induction motor drive and output voltage THD is further reduced by employing RSCC circuit.
Keywords: Multilevel Inverters, Voltage Balancing Circuits, Resonant Switched Capacitor Converter (RSCC), Phase Disposition Pulse Width Modulation (PDPWM).