MICROPROCESSOR CONTROL OF PWM INVERTERS FOR SINUSOIDAL OUTPUT WAVEFORM SYNTHESIS (POWER ELECTRONICS, MICROPROCESSOR, DEAD BEAT, DIGITAL, SOLID STATE POWER CONVERSION).

摘要

This dissertation investigates a new technique to generate high quality sinusoidal output waveform for medium power applications. A microprocessor based closed loop digital control system measures the output and controls the inverter switches to produce the required PWM pattern to synthesize the low total harmonic distortion (THD) sinusoidal output voltage. This scheme inherently provides very good voltage regulation, phase positioning and compensation for load disturbances and nonlinear loads.;A simple difference equation is developed to represent a "plant" consisting of a single phase bridge inverter, LC filter and load. A dead beat control algorithm to control the inverter is proposed so that the output voltage follows the sinusoidal reference.;Digital computer simulation of the system is carried out to study the performance of the inverter system under linear and nonlinear loads. A setup consisting of a single phase transistor bridge inverter and an Intel 8086 microprocessor based digital controller is constructed to experimentally verify the results.;The concepts developed for the single phase circuit are applied to control a three phase bridge inverter circuit to produce three phase sinusoidal output waveforms.