Experimental Verification of a Battery Energy Storage Systemfor Integration with Photovoltaic Generators

This paper presents the experimental verification of a 2 kW battery energy storage system (BESS). The BESS comprises a full-bridgebidirectional isolated dc-dc converter and a PWM converter that is intended for integration with a photovoltaic (PV) generator,resulting in leveling of the intermittent output power from the PV generator at the utility side. A phase-shift controller is alsoemployed to manage the charging and discharging operations of the BESS based on PV output power and battery voltage. Moreover,a current controller that uses the𝑑-𝑞synchronous reference frame is proposed to regulate the dc voltage at the high-voltage side(HVS) to ensure that the voltage ratio of the HVS with low-voltage side (LVS) is equivalent to the transformer turns ratio. Theproposed controllers allow fast response to changes in real power requirements and results in unity power factor current injection atthe utility side. In addition, the efficient active power injection is achieved as the switching losses are minimized. The peak efficiencyof the bidirectional isolated dc-dc converter is measured up to 95.4% during battery charging and 95.1% for battery discharging