Research On Key Technologies And Applications Of APF

Recent years, with the development of the social economy, power electronics has been widely used. These devices save energy and improve production, but also generated a lot of harmonics because of their nonlinear characteristics. Harmonics affects the quality of power supply and the normal operation of the user equipment. Active power filter is the ideal choice of governance harmonics, compared to traditional passive filter, its performance is more superior, and less affected by the influence of parameters.This article focuses on the three-phase four-wire capacitance midpoint active power filter, explained how it works and establish a mathematical model. This paper presents several common harmonic current extraction methods, analysis of its principles and implementation. The paper also study the control strategy of active power filter, which mainly include current inner and outer voltage control. PI control and PR control are introduced in the current loop and regulator links and equalizing links are designed in the voltage loop.In this paper, we design the APF's software and hardware and choose the main circuit parameters. We analyze the function of each part, design the DSP program, FPGA program and touch screen program respectively.With the help of PSIM, the model simulations of shunt APF are established. Simulation results show that the shunt APF play a role in better compensation to harmonic currents and the compensation has good dynamic characteristics. And the shunt APF of capacitor midpoint four-wire is also able to compensate for unbalance.Finally a shunt APF device which can be used in the three-phase four-wire is developed based on the design above. And a large number of experiments are made with the use of this device. It is proved by the experiment that the detection algorithm and the control strategies proposed in this paper are viable and effective, which ensures the performance of the shunt APF.