A Modified Method of Voltage Controller for Three Phase Induction Motor using Three Phase Voltage Source Inverter

Abstract

A general pulse-width modulation (PWM) method for control of four-switch three-phase inverters is presented. The proposed vector PWM offers a simple method to select three or four vectors that effectively synthesize the desired output voltage, even in presence of voltage oscillations across the two dc-link capacitors.This paper offers a new analog controller, which has a fixed switching frequency as well as combined modulation and regulation. It employs a circuit-level decoupling method similar to those in and can be implemented by simple logic and an analog circuit. With the proposed controller, the three-phase inverter is proven to possess the ability to maintain good regulation of output voltages over 0%?100% rated linear or nonlinear loads, reject source voltage noise, follow abrupt reference changes, and withstand extreme load transients. The inverter under this control has low switching loss, as two of its six switches in the power converter are not operated at switching frequency at any instant.