In view of the considerable loss due to unstable switch frequency and wide frequency range in high harmonic distortion existing in traditional hysteresis control strategy for the three-phase voltage source pulse-width modulation (PWM) rectifier

an improved control algorithm for active power filter based on random variable bandwidth hysteretic current control is proposed. It allows significant reduction in the loss of switching produced by variable switching frequency and accurate compensation of harmonic currents. In order to modulate the accurate bandwidth of hysteresis current control

the approach based on the characteristics of load in the power system generated a bandwidth with random function able to widen the range of switching frequency

while effectively reducing the harmonic distortion rate and the switching loss. Simulation and test results of the shunt active power filter show the performance of the improved control strategy is feasible.