Single-phase Circuit Research And Design Of The Shunt Active Power Filters

As more and more nonlinear power electronic devices with varied types and capacities were applied to the power systems nowadays, quite a large amount of harmonic current flowed into the power systems, which polluted power system badly, and so do harm to power system. So how to compensate harmonic current had been the research focus of the experts and scholars at home and abroad. An important trend of harmonic suppression is to use APF(Active Power Filter). As APF could conquer the limitation of PPF(Passive Power filter) and compensate harmonic current Real-time, now it engages researchers' attention more and more.Latest references and technology of APF at home and abroad were introduced, topology structures and principles of APF were explained, and some harmonic current detected methods were expounded in this paper. Based on a single-phase harmonic current detection method, Lagrange extrapolation, Gray theory and Time serials analyse were studied to be used in harmonic current prediction. From theory analyse and simulation result, all three prediction methods could predict harmonic current Real-time with high precision, and improve the capacity of harmonic compensation. Gray theory and Time serials analyse could predict with higher precision, but the first method have a large compute spending, the second method have a simple calculate equation and with a large compute spending when modeling. Lagrange extrapolation have the simplest arithmetic and with highest precision in three methods.An APF simulate model with Lagrange extrapolation and Deadbeat Control method was set up with Matlab/Simulink software. Simulated results indicated that , the model could detect harmonic current and compensate it Real-time whether the source voltage was distorted or not, and its compensate effects excelled triangle modulate methods without harmonic current prediction.An experiment system with TMS320F2812 was builded to validate harmonic current prediction methods and current control methods. The power circuit parameters of APF were designed, hardware and software of control system were also designed. Experiment results indicated that APF in this paper could detect harmonic current Real-time and have a well dynamic compensation capability.