Performance of Micro Controller Based Seven Level Diode Clamped Multilevel Inverter for Three Phase Induction Motor

This paper presents a micro controller based control of multilevel inverter for three phase Induction motor. Pulse Width Modulation (PWM) techniques; introduced three decades ago, are the most used methods to control the voltage and frequency supplied to electrical AC machines. Multilevel inverter has gained attention in recent years due to its high power capability associated with lower output harmonics. Several multilevel topologies have been reported in the literature and this paper focuses on Diode Clamped multilevel inverter built to implement the proposed conduction table with seven voltage levels. Gating signals an regenerated using P IC microcontroller. The performance of the inverter has been analyzed and compared with the result obtained from theory. A scheme based on 7-level PWM inverter, which control a high performance 8-bit standard microcontroller with gate driver circuit and additional hardware is used, which allows a flexible and economical solution. The output voltage can be varied in a large range and with a good resolution. Experimental data obtained from an induction motor drive will be presented and to check staircase sinusoidal waveform of line voltage on CRO.

Keywords: Diode clamped multilevel inverter; Multicarrier SPWM technique; Microcontroller,