An active filter for reactive and harmonic compensation using voltage source inverter

An active power compensator is presented by employing voltage-source pulsewidth modulated (PWM) inverter to suppress AC harmonics by injecting compensating current to the AC system. The control strategy using switching devices is proposed on the basis of the instantaneous power theory. This is different in principle from the conventional control strategy. It has two important features to maintain a unit power factor for input source, as well as to reduce harmonic currents generated by nonlinear load. Two current methods are discussed, and their computer simulations are used to compare with the experiment results. For ramp comparison control, a phase-leading controller is also proposed to improve the system response. An experimental prototype system is constructed to verify the analysis and design