Optimal Design DC-Link Capacitance for Single-phase PV Inverters with Grid Support of Reactive Power

Solar photovoltaic (PV) grid-tied systems increase significantly in power output capacities in recent years. Such sys- tems are used to supply only active power to the AC network. The function of grid support becomes essential for network stability, considering the high penetration of photovoltaic power systems and the intermittency. Small-scale PV systems are typically designed for single-phase grid interconnection. The accumulated capacity is becoming significant thanks to various incentives. The DC/AC conversion requires many DC-link capacitors to buffer any potential power mismatch and maintain a steady- state voltage level. This paper presents a theoretical analysis method to size and optimize the DC-link capacitance for single- phase systems. Simulation proves its effectiveness by satisfying steady-state performance and the function of reactive power compensation for grid support.