Sinusoidal Current Control based Shunt Active Power Filter for Current Harmonics Reduction

Most of the power quality issues in power system are due to non-linear loads. The nonlinear load draws non-sinusoidal current from the AC mains which causes load harmonics and increases reactive power leading to pollution in power system. Shunt Active Power Filter (APF) has proven to be effective in improving power quality of distribution network. It compensates load current harmonics and reactive power simultaneously. The working of APF depends on its control strategy which includes generation of compensating reference current and generation of proper gating signal to make APF inject this reference current. This paper presents Sinusoidal current control (SCC) strategy for controlling the operation of shunt APF under balanced and unbalanced source voltage condition. This control strategy is based on instantaneous Reactive Power Theory (IRPT) and contains a positive sequence detector for detecting fundamental positive sequence component of input signal. The shunt APF contains a PWM current controlled voltage source inverter which is connected at the point of Common Coupling (PCC). The gating signal of VSI is derived from hysteresis band current controller (HBCC) and capacitor voltage is kept constant using a PI controller.