Sliding mode based space-vector hysteresis current control for active power filter

An improved space-vector hysteresis current control (HSVPWM) is put forward for the active power filter (APF) based on the sliding mode. The sliding mode controller (SMC) is adopted to enhance the disturbance rejection ability of the outer DC voltage loop. To improve the control precision of the APF system, an enhanced HSVPWM method is introduced in the inner current loop. It employs two threshold values to determine the operation state. Then, the proper switching states are obtained according to the control requirement and the sectors of the derived voltage vector and current vector. This can eliminate the drawbacks of the classical HSVPWM method, such as the low control precision, poor transient performance and so on. The effectiveness of the proposed HSVPWM method is verified by the simulation and experiment. Compared with the classical method, the current total harmonic distortion in the steady state is reduced by more than 37%, and the transient setting time is shortened by at least 56%. The results indicate the better performance of the proposed method in both the steady and transient states.