Control of Hybrid PV System with Battery Storage

A control scheme for a hybrid solar inverter is proposed which can operate the inverter in both ‘on grid’ and ‘off grid’ modes and have a seamless transfer between the two methods. The input for this inverter is obtained from multiple strings of PV arrays. An individual maximum power point tracking (MPPT) for each string is implemented to optimize the power extraction from the PV module. A battery bank controlled by a charge-discharge regulator is interfaced with the DC bus of the inverter. In grid-connected mode, this battery bank can be charged from the grid as well as from the PV panel depending on user preference. In off-grid mode, this battery compensates for the mismatch between the generation from the PV panel and the load. The proposed control scheme for the hybrid solar inverter is validated through extensive simulation studies.