SAPF control strategy under the condition of non-ideal source voltages

This paper presents the accurate calculation approach of the compensating current reference of shunt active power filter (SAPF) under the unsymmetrical and non-sinusoidal supply voltage conditions. The proposed approach is based on the rotating coordinate transformations of three-phase voltages and currents and the projection of d-q current in the direction of d-q voltage. The resulting current reference equals to the difference between the instantaneous current of nonlinear load and its fundamental positive sequence active component. Used in the three-phase three-wire network, it can determine arbitrary single order harmonic current. Further, this paper reports the dead-beat current control for SAPF to track the current reference under the unsymmetrical and non-sinusoidal supply voltage conditions. Theoretical analysis, simulation and experimental results demonstrate the effectiveness of the proposed calculation and control approaches. Besides the control of SAPF, the proposed calculation and control approaches can be applied to the control of other types of active power filter.