A comparative study on the active power filter control strategy for independent and small power system

Aiming at the serious influence on the power frequency stabilisation for independent power system when its loads are largely changed, a control strategy of active power filter is presented. Firstly, the principle of second-order direct type IIR (infinite impulse response) digital notch filter is described, and the frequency real-time detection model is established based on least mean power (LMP, p = 3) adaptive algorithm to track the notch filter parameters. Then, combining the instantaneous reactive power theory and hysteresis current method, the simulation model of active filter control strategy with power frequency’s change is established. Finally, the simulation results proved that the active power filter model can track the changing frequency quickly and compensate harmonic current accurately. Therefore, the power quality and reliability of the small power grid are enhanced.