A Novel Control of Series Active Power Filter without Harmonics Detection

The main idea of conventional control methods for series active power filter (SAPF) is to control the SAPF as frequency-selective impedance or voltage source. In these conventional control methods, a real-time instantaneous harmonics detection algorithm is essential and comparatively complex, which is usually implemented with a digital signal processor (DSP) therefore makes the control circuit complicated and high cost. Furthermore, the time delay caused by the harmonics detection and its digital implementation will deteriorate harmonics compensation performance. In this paper a new control method for SAPF is proposed. The idea of the proposed control is to control the compensation voltage injected by SAPF to trace the multiple of whole line current to achieve current harmonics suppression. Since the control reference signal directly utilizes the detected line current without calculating harmonics, the proposed control actually eliminates the harmonics detection process. In addition, the DC-side voltage control is indispensable in this control to maintain the active power balance for the proper operation of the SAPF system. Compared to traditional control methods, the proposed control is therefore much simpler and easier to implement at low cost. And the time delay caused by complicated harmonics calculation does not exist any more. Simulation and experimental results are presented to verify the validity of the proposed control method and the performance of the SAPF.