Shatha k. Baqir
Abstract
Traditional high-frequency pulse width modulation (PWM) inverters for motor drives have several problems associated with their high switching frequency which produces high voltage change ...
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Traditional high-frequency pulse width modulation (PWM) inverters for motor drives have several problems associated with their high switching frequency which produces high voltage change (dv/dt) rates. Multilevel inverters solve these problems because their devices switch at the fundamental frequency. The concept of multilevel voltage source inverter is explained. In this paper the cascade inverter is a natural fit for induction motor drives because of the high VA ratings possible and it uses several levels of separate equal dc voltage sources which would be available from batteries or fuel cells. The switching angles of switch devices are determined by optimized harmonic stepped waveform (OHSW) technique to reduce the output harmonics of cascade multilevel inverter (CMLI) for induction motor is proposed, as a result the efficiency of system has improved. Simulation results show the superiority of this inverter over 2-level inverter and were carried out using ORCAD package.
