The research of novel double hysteresis current control method for the shunt active power filter

In order to improve the current control performance of the SAPF, a novel double hysteresis control method is proposed in this paper. The conventional double hysteresis control method is used to obtain the optimal voltage that can control the error of phase current quickly according to the distribution of reference voltage, the location of current error and whether the current error is beyond the limits or not. Although this method can provide fast current response, and decrease high-order harmonics and switching frequency, it decreases the compensation accuracy because when the current error is in inner loop, the inverter takes no actions. In view of this problem, the Active Disturbance Rejection Controller (ADRC) is introduced to the control of inner loop, both inner and external uncertainty are treated as unified unknown disturbances that are estimated by the extended state observer and compensated by the nonlinear state error feedback control law, the Particle Swarm Optimization (PSO) algorithm is used to optimize the ADRC parameters, so the complicated calculation is avoided. Thus, the accurate measurement of harmonics is not required, the utilization ratio of voltage is improved, and the adaptability of control system is strong. The simulative results show its good static/dynamic performance and strong robustness. © 2013 Binary Information Press.