Fluctuating photovoltaic (PV) output power reduces the reliability in power system when there is a massive penetration of PV\ngenerators. Energy storage systems that are connected to the PV generators using bidirectional isolated dc-dc converter can be\nutilized for compensating the fluctuating PV power.This paper presents a grid connected energy storage system based on a 2 kW\nfull-bridge bidirectional isolated dc-dc converter and a PWM converter for PV output power leveling. This paper proposes two\ncontrollers: a current controller using the d-q synchronous reference and a phase-shift controller.Themain function of the current\ncontroller is to regulate the voltage at the high-side dc, so that the voltage ratio of the high-voltage side (HVS) with low-voltage\nside (LVS) is equal to the transformer turns ratio.The phase-shift controller is employed to manage the charging and discharging\nmodes of the battery based on PV output power and battery voltage. With the proposed system, unity power factor and efficient\nactive power injection are achieved. The feasibility of the proposed control system is investigated using PSCAD simulation.
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