Research On Single Phase Shuntactive Power Filter And Its Control Method

With the use of a large number of nonlinear loads, especially solar power generation system is connected to grid, a large amount of harmonic current is injected into grid, which polluted power system badly, and caused great harm to power system. So harmonic suppression is extremely urgent. There are many methods of harmonic suppression, active power filter (APF) is one of the most important method. As APF can not only track harmonic current real-time, but also achieve dynamic compensation harmonic current, it had been widely used.The study of APF, which is one of the most effective methods to suppress harmonic current, focused on harmonic current detecting algorithm and compensating current control method. This paper includes mainly compensating current control method and design of main circuit of APF.This paper starts from power system harmonics in chapter 1. Firstly, its fundamental principle, origin, harm and standard are introduced. Secondly, two methods of harmonic suppression and research status in home and abroad are described. Finally, project source and main jobs of this paper are proposed.Classification and work principle of APF are described detailedly in chapter 2. Besides, it analyzes rectification circuit with inductive load and capacitive load separately. The main contents of chapter 3 are harmonic current detecting algorithm and compensating current control method. An instantaneous harmonic current detecting method based on the phase distinguishing technology, as one of harmonic current detecting algorithm, is put forward. Compensating current control method includes current tracking control method and voltage tracking control method. In current tracking control method, hysteresis control method and triangular wave comparison are mainly introduced. In voltage tracking control method, a kind of space vector voltage control method of single-phase shunt active power filter (SPSAPF),which is based on space vector voltage control method of three-phase shunt active power filter, is proposed. This is an innovation of this paper. The main contents of chapter 4 is design of hardware circuit of SPSAPF, which involves choice of capacitor voltage and capacitor, control of capacitor voltage, choice of power device and inductor, design of control system hardware. The design of control system hardware contains design of control circuit, drive circuit, sampling circuit and protect circuit. The contents of chapter 5 includes software system design and modeling of SPSAPF. It verifies the correctness of the whole system through the analysis of simulation results. Finally, this paper is summarized in chapter 6, and it also gives an outlook of future works.