Software Design On The Full Digital Controlled Active Power Filter

With the increasing application of nonlinear loads in power network, harmonic pollutionbecomes more and more serious and has been one of the most important factors to impact powerquality. Comparing with the passive filters, active power filters (APF) have many advantages,for example, good filtering characteristics, immune to power network impedance, simultaneouscompensation for harmonic currents and active currents etc., so the APF is widely developed andused.The harmonic pollution and its harm are introduced, and a general description about thedevelopment of harmonic elimination in power system and application foreground of ActivePower Filter is given in this paper at first. The advantage of digital control system based on DSPis also introduced. The principal and structure of Active Power Filter are expatiated. Based on detheory of instantaneous reactive power, detecting method for high frequency harmonic current ispresented and the diagram of actualization for digital control system is put forward. In this paper,a full Digital Active Power Filter based on DSP is designed, including signal adjusting, sampling,and so on. Computing of instruction current and controlling of system is realized in one DSP.Hardware system using TMS320F2812 is completed, and the design of software interface andthe result are given in this paper.In this paper, simulation models of Active Power Filter system in SIMULINK environmentof MATLAB software are built for theory analysis. The software design is the most importantpart in this paper, including the design of phase locked loop (PLL), low pass filter (LPF) and soon.The fact that Active Power Filter has good application foreground prove that its researchand application are very important in the future.