Research On The Simulation Of Shunt Active Power Filter In Three-Phase Three-Wire System

With the widespread use of a large number of power electronic devices in recent years, lots of harmonics is injected into the grid. The harmonic pollution is pushing us to face it. Among various harmonic suppression measures, active power filter has become a hot point of research because of its excellent performance.Firstly, this paper introduces the generation and harm of harmonic. Then the huge advantage of active power filter comes up by comparing different extant harmonic suppression measures.Then the system structure and principle is introduced. On this basis, the math model of APF is established. At the meantime, several fields are intensive studied, like harmonic current detection, control system, etc.Accurate and rapid detection of harmonic current is the precondition of harmonic compensation by APF.Applying the d-q detection method based on park transformation to the situation, fundamental current is transformed to the DC current in d-q coordinate. After the currents in d-q coordinate passing through the sliding-window low-pass filter, harmonic current is conveniently detected.The APF control system is the key factor deciding the effect of harmonic compensation. By establishing the math model of APF, decoupling currents on d-axe and q-axe, a first-order current controller using the PI control strategy, is designed in this paper. Meantime, in order to stabilize the DC side voltage, the closed loop of voltage control system is added in.According to theory and parameter selection related in this paper, the simulation model by SIMULINK module of MATLAB is founded. The simulation verifies the functions of different modules, which proved the theory in this paper right. In addition, harmonic compensation tests with different main curcuit parameters are carried on to find the optimized parameters.Overall, the simulation results point out that APF system performs good in harmonic suppression.