Application Of Repetitive Control In Active Power Filter

With the development of power electronics, related equipments are increasingly used all over the world. Because of the nonlinear characteristic of these equipments, current of the power grid is badly polluted day after day, endangering the safety of the power supply. In order to improve the power quality, Active power filter is used to compensate harmonic current of nonlinear load to decrease harmonic pollution of the grid. This paper introduces the development and main circuit of APF and its principleIn order to improve compensation performance, repetitive control is used in control system. This paper introduces structure of repetitive control, emphasizes on the design process of links in repetitive control, simulation in MATLAB and experiment demonstrates its validity and feasibility.This paper introduces basic structure of digital control system. Choose hardware devices should meet require of the real-time control to digital system; properly peripheral circuit is needed to cooperate with DSP board, its structure and principle are illustrated in paper. Fully equipped hardware ensures algorithm's realization.In software of control system, this paper introduces DSP programming environment, language and basic structure of DSP program. The procedures of programme are explained by flow chart. From sampling, calculation time delay, control object zero-order discretization, digitalization process influence to Active Power Filter is analyzed in this paper. After control object's discretization and programmed in differential equation form, close loop debug can be achieved. This real-time debugging method is immune to the main circuit, system debugging difficulty is reduced, develop time is shorten.