Space vector modulation direct power control of grid-connected photovoltaic converter with reactive power compensation

Photovoltaic (PV) energy is one of the fastest growing renewable energy resources. Most PV units are connected to the distribution or transmission grid by voltage source converters (VSC). As the number and size of grid-connected PV units increase, the requirements placed on them by grid operators are changing. Among the new requirements by some grid codes is that PV units should help with voltage support by reactive power compensation. One significant advantage of a grid connected PV system capable of reactive power compensation is that it can operate during the night as a reactive power compensator. This paper presents the control of a grid-connected PV system with reactive power compensation using Direct Power Control with Space Vector Modulation (DPC-SVM). Simulation results for both daytime and night-time operation are presented. The results show good dynamic and steady-state performance, decoupled control of active and reactive power, low distortion in the output voltage and current, and constant switching frequency over a wide range of conditions.