Simulation And Experimental Study Of Repetitive Control In The APF

With the large-scale application of power electronic devices, the problem of harmonic pollution is becoming increasingly serious. Active power filters, as a reliable means of harmonic control,are used widely. The current tracking control method is the key factor on the effect of the active power filter compensation.The conventional proportional control method is unable to track sinusoidal signals without steady-state error. Repetitive control based on the internal model principle, can track sinusoidal signals without steady-state error, since it introduces infinite gain at the sinusoidal frequencies. However, the dynamic response of repetitive control is slow. This paper investigates the principle of repetitive control and compares the effects with different parameters based on an active power filter. This thesis is organized as follow:The first chapter introduces the background of harmonic pollution, the main active power filter program topology, harmonic extraction algorithm, as well as current tracking control scheme.The basic concepts of the internal model principle and the characters of repetitive control are introduced in the second chapter. Both steady state and dynamic performances are analyzed by Simulink. Proportional control with a combination of repetitive control method can effectively improve the dynamic response characteristics of the system.The third chapter introduces the three-phase four-wire shunt active power filter topology and mathematical model. And according to the control structure of the APF system, embedded in repetitive control algorithm, analyzes repetitive control loop parameter selection for the effect of the current loop tracking.Repetitive control embedded in the active power filter control system, the stability of the system is analyzed. Steady-state and dynamic performance are verified by a15kVA active power filter.Chapter five is the conclusion and prospects of the study.