Based on the DC side of the coupling transformer digital implementation of active filters
|Keywords||APF Digital Control Rectifier Harmonic Control Transformer|
Harmonics on power quality and reliable operation of the grid constitutes a great threat. APF (Active Power Filter, APF), you can change the size and frequency of the harmonic compensation, able to solve a single passive filter filtering effect and system impedance characteristics change and other issues, has become the most effective harmonic governance means. Among the many harmonic source, class load caused by the rectifier is most common, which some scholars have proposed the DC side APF control measures, including the DC Side Series APF for the load capacitor filter with good harmonic inhibition. However, the conventional DC Side Series APF does not isolate the main circuit and the rectifier bridge, there is when the input voltage level rises, APF storage capacitor and the switching device voltage stress and other problems, this paper studies this problem, do the following work. In introducing harmonic generation, hazard mitigation methods as well as topological classification of active power filter based on the analysis of the shunt and series APF APF works, discusses their effects on the different nature of the compensation characteristic harmonic source. That: conventional DC side series with the rectifier bridge APF on the main circuit without isolation, APF high voltage energy storage capacitor, which not only increases the storage capacitor rating, improve the circuit costs, but the APF switching device voltage stress increases, reduce circuit reliability. In response to these problems, this paper based on the DC side of the coupling transformer Series Active Power Filter. The topology of the DC side through a coupling transformer and rectifier bridge APF main circuit isolation, and by adjusting the transformer turns ratio can effectively reduce the APF storage capacitor voltage and switching stresses. By topology works and energy flow analysis to prove the coupling transformer based DC Side Series APF is correct. Meanwhile, simulation studies have demonstrated the effectiveness of this topology. Then, with a single-phase transformer DC Side Series APF extended to the three-phase system is proposed based on a three-phase transformer-coupled DC Side Series APF, analyzes its working principle and simulation studies. Finally, the traditional analog control circuit complexity, difficult to debug, algorithms and parameter adjustment inconvenient problem, a DC-side series APF on digital implementation. With TMS320F2812 DSP to control the chip, developed with a capacity of about 100VA transformer coupled with a single-phase DC Side Series APF prototype, the hardware system and software system design. Experimental prototype debugging, experimental results verify the coupling transformer based DC Side Series APF adopts digital control, not only to achieve the rectifier class load harmonic compensation, but also reduces the energy storage capacitor voltage, resistance to improve the system interference capability and control stability.