The Research And Development On Active Power Filter Based On DSP

The ideal power system needs to be supplied with sine voltage whose frequency and amplitude are both stable. To three-phase AC power system, the currents and voltages must be equal of amplitude and the phase-shift between each other should be 120 of positive order. Because of the elements which run under nonideal linearity and unentire symmetry in the power system, the loads which are different and change randomly, the methods which adjust and control the system faultily and operate improperly, the disturbance and the malfunction which happen somewhere, the current and voltage in the supply system are distorted seriously and thus large amount of harmonics are produced. Those harmonics pollute the supply system, harm devices which may be over-hot, noisy, vibrant and that may be destroyed in the worst instance. The harmonics compensation has become today's hot topic in Power Engineering.Passive filter and active power filter (APF) are the two primary approaches for eliminating harmonics. Comparing with passive filter, APF has many advantages, which is insensitive to system impedance and can be used to compensate harmonics. APF plays an important role in eliminating harmonic. Most researches on APF are focused on main circuit configurations (series-type, shunt-type, compound-type), harmonic current detection approaches and control strategies to compensate current ,etc. This paper mainly deals with the design of APF based on harmonic current compensating approaches.APF control realization can be either digital or analogical. The advantage of digital compensating control(DCC) is that it can compensate harmonics to a precision level and is independent of the surrounding environment. But DCC needs high-speed real-time chips to deal with digital signal processing, so has high price; analog compensating control(ACC) demands hardware very rigidly. The design of APF is very important to both ACC and DCC. The dissertation, reseaching on three-phase-three-line power-network, based on the theory of digital signal processing(DSP), has done the real-time dynamic simulation of APF using the software of MATLAB, and the result shows that the method of harmonics detecting and the scheme of current controlling are both pratical and effective. An experimental laboratory prototype scheme is proposed.