MODIFIED SVPWM FED NINE SWITCH INVERTER FOR MOTOR LOAD

Abstract

The nine-switch inverter has been suggested in order to reduce the switching components and the cost of regular six switch inverter. In this paper, the conventional Space Vector Modulation (SVM) and Level-Shift Space Vector Pulse Width Modulation (SVPWM) design of nine-switch inverter is contemplated, controlling the two independent parallel ac induction motors without the shoot-through in the inverter leg. The SVPWM is proposed for minimizing total harmonic distortion (THD). The dual output voltages and phase currents can prevent the distorted attribute, which is originated by the crossover of the modulating signals. This will suitable for high power inverter application where cost and efficiency are vital decision factors. The mathematical models are suggested by the level shift SVPWM scheme and based on the zero-sequence injection principle. The offset control decrement are arranged by the interconnection of the modulation indices in level shift of the SVPWM modulating signals. The suggested modulation performance has been confirmed by the simulated implementation that is effectively carried out on the applicability of the proposed algorithm, the high modulation index is needed.