Three Phase Four Wire System APF Control Strategy Research And Simulation

Today’s power system, the power electronic device and the wide use of nonlinear load,resulting in the power of reactive power and harmonic content rising to power systemrunning environment caused great pollution, seriously affected the quality of electricenergy, so the comprehensive governance of the pollution to power network is more andmore important. The traditional passive power filter can compensate specific harmonics,and thus has its limitations. And active power filter (APF) for the emergence of withoutsource power filter insufficiency, it can dynamically governance harmonic, and able toreactive power compensation, so the research of active power filter have attracted wideattention. In three phase four wire system of power grid system, there are a lot of zerosequence current and negative sequence current, this to APF system put forward higherrequirementThis paper adopted the three phase four wire system parallel type hybrid activepower filter, firstly introduces the working principle of APF, the main circuit structure,passive filter principle, structure. Choose the comparatively mature algorithm-based oninstantaneous reactive power theory algorithm for harmonic current detection, and thevoltage ring output coupling to the current ring active loop, control dc side voltage withina certain range, and reduce the fluctuation and improve the compensation effect; UsingPWM triangular wave comparative way for instruction current and compensation currenttracking control, get8switch device drive signal, and finally drive equipment producecompensation current flow into the power grid.Because of this paper USES is the hybrid system, so based on the introduction ofactive power filter, but also introduced the principle of filter without source. In the usualsystem, dc side of the voltage control strategy is widely adopted PI control, but there maybe integral saturation phenomenon, so, this paper adopted the resistance to integralsaturation PID as the dc side of the control strategy.In this paper MATLAB2009b on system dynamic simulation model, and on the partof the simulation results are analyzed. Comparison on PF and mixed PF later system forharmonic suppression situation. Analysis of the resistance to integral saturation PIDcontrol strategy effect.Finally, based on the present APF system data transmission big characteristic,proposed based on Bus-LVDS Bus interface card communication strategy. The hardwarecircuit part adopts DSP+FPGA form, DSP is mainly used for current detection part, andFPGA is mainly used for power grid voltage lock and PWM wave generation.