A hybrid photovoltaic and battery energy storage system for high power grid-connected applications

This paper presents a hybrid PV-battery grid connected system suitable for high power PV power applications. High power PV systems have impressive voltage fluctuation with regards to their maximum power point voltage. Using DC/DC converters to regulate this voltage is inefficient in high power systems as it adds an extra power conversion stage. On the other hand switching frequency, voltage stress as inverter limitations and power quality issues should be considered in high power applications. Central PV structures because of low efficiency and high cost inverters are not suitable for high power systems. Maximum power extraction from PV together with active and reactive injected power control is another challenge in high power system. Z-source multilevel inverter for PV arrays together with battery energy storage systems is a suitable solution for high power application. This paper proposes a control strategy for this hybrid system. A simulation with PSCAD has been done to validate the control strategy. Simulation results show how proposed control and topology satisfies high power requirements for PV grid connected systems.