Control Strategy Research Of Single PWM Inverter Under Nonlinear Loads

With gradually development of digital signal processing, As an important part ofPower Electronics, Inverters play a vital role among Distributed Generation System(included Renewable Energy Sources) and Uninterruptible Power Supply (UPS).However, Inverters often face problems caused by nonlinear loads, and nonlinearload’s own characteristic of intermittent current often leads to distortion inverter outputvoltage. To aim at the problem, this paper plays profound research on a typical nonlinearload(rectifier load), and raises a novel rectifier load model based on dead area characteristic,also analyses underlying cause of output voltage distortion caused by rectifier load.Numerous study have proved that repetitive control strategy(based on Internal ModelPrinciple) plays good control effect when deals with periodic disturbances such as deadtime, nonlinear load, etc. so this paper implement detailed research on fundamentalprinciple and implement method of repetitive control, and fine steady state behavior isproved by Simulink. Furthermore, so as to improve the dynamic performance of inverter, acompound control method composed of repetitive and doubleloop control is introduced,where the repetitive controller’s controlled object is the inverter under doubleloop control.Since the compound control arithmetic includes inductance current inner loop, therepetitive compensator is simplified and the nonlinear load disturbance is effectivelyreduced. This method is proved by Matlab Simulink result.