Study on Proportional Resonant control strategy of single-phase SVG

Single-phase Static Var Generator (SVG) is widely used in fields like electrified railway and Distribution Generation (DG) etc. However, it has special requirements and difficulties, e.g. a single-phase SVG is not easy to achieve satisfactory performance of tracking the AC reference comparing with the three-phase one. In three-phase system, a PI controller can track the reactive current without steady-state error theoretically because it is converted to DC component in synchronous rotating coordination. What´s more, because of the constraints of device switching capacity and grid voltage disturbances like low-order harmonic distortion, the harmonic characteristics of device output current is poor. Aiming at improving the accuracy of reactive power compensation, ability of anti-disturbance of grid voltage and the distortion performance of the output current, this paper presents a Proportional Resonant (PR) controller with multiple resonant frequencies for single-phase SVG. The controller design is taken in z-domain for convenient digital implementation. The superiority of control strategy is verified through created simulation models and experimental prototype.