Elimination of Harmonics Using Active Power Filter Based on DQ Reference Frame Theory

— Active power filters have the following multiple functions; harmonic filtering, damping, isolation and termination, reactive-power control for power factor correction and voltage regulation, load balancing, voltageflicker reduction, and/or their combinations. Significant cost reductions in both power semiconductor devices and signalprocessing devices have inspired manufactures to put active filters on the market. This paper presents a method for obtaining the desired reference current for Voltage Source Converter (VSC) of the Shunt Active Power Filter (SAPF) using Synchronous Reference Frame Theory. The method relies on the performance of the Proportional-Integral (PI) controller for obtaining the best control performance of the SAPF. Using Reference Frame Transformation, reference signals are transformed from a−b−c stationery frame to 0 − d − q rotating frame. Using the PI controller, the reference signals in the 0 − d – q rotating frame are controlled to get the desired reference signals for the Pulse Width Modulation. Keywords— Pulse Width Modulation (PWM), Shunt Active Power Filter (SAPF), Voltage Source Converter (VSC).