The Research On Active Power Filter Based On One-cycle Control Technology

Harmonics for the grid in terms of great harm, people have long been concerned about this issue. Was first seen to miss the power filter (LC filter) for use in power system. However, this method is to filter out the harmonic frequency is limited and fixed, can not adapt to the development of science and technology, so the active power filter (APF) technology is rapidly developed.For active power filter technology mainly concentrated in the transmission grid, which is three phases. However, with the use of new types of electrical equipment, the user terminal to a port of a large number of harmonics injected to the grid. Therefore, for the three-phase four-wire active power filter is imminent.The traditional method of compensation is a static compensation, harmonics, reactive power to do a static compensation. Limitations of such compensation is considered, starting from the general characteristics of the load global compensation effect is difficult to do everything. APF, but just be able to compensate for the shortcomings of the traditional way, in accordance with the given control strategy, the compensation device control, so that it can produce a reverse current to the harmonic current, then the harmonic compensation, thus eliminating the system harmonics.One cycle control method is a nonlinear control method, by controlling the duty cycle switch in each cycle the average of the variable and the control reference signal equal to or proportional to, thus eliminating the steady-state and transient errors. One cycle control method has a fast response, anti-power interference and control circuit is simple and reliable.This paper analyzes the introduction to a variety of current control strategy method, and analyzed the working principle and mathematical model of parallel single-cycle control active power filter in three-phase four-wire system.Finally, the MATLAB simulation results verify the theoretical analysis to prove the correctness and feasibility of single-cycle control for the actual device.