The main purpose of this study was to develop a photovoltaic module array (PVMA) and an energy storage system (ESS) with charging and discharging control for batteries to apply in grid power supply regulation of high proportions of renewable energy. To control the flow of energy at the DC load and charge/discharge the battery uniformly, this work adapted a bidirectional buck–boost soft-switching converter and the maximum power point tracking (MPPT) technique of the photovoltaic module array. First, a boost converter is used with the perturb and observe (P&O) method, so that the photovoltaic module array can work at the maximum power point (MPP) at any time. When the output power of the photovoltaic module array is greater than the load power, the excess power is used to charge the battery; on the contrary, if the output power of the photovoltaic module array is lower than the load power, the battery discharges for auxiliary power supply. This makes the voltage of the DC link maintain a constant value. The monitoring circuit sends the voltage and current signals to the TMS320F2809 digital signal processor (DSP) produced by Texas Instruments to control the battery charging/discharging voltage and current. The photovoltaic module array works at the MPP to improve the performance of the overall energy storage system. Finally, the actual test result shows that the soft-switching converter used in this work, when compared to the hard-switching converter, can improve efficiency by nearly 4% when the load power is above 125 W. When the photovoltaic power generation system operation is between 150 W and 400 W, the proposed uniform charging and discharging architecture can rapidly reach uniformity.

The purpose of this paper is to develop a photovoltaic module array with an energy storage system that has equalizing charge/discharge controls for regulating the power supply to the grid. Firstly, the boost converter is used in conjunction with maximum power point tracking (MPPT) such that the photovoltaic module array (PVMA) can output maximum power at any time. The battery equalizing charge/discharge architecture is composed of multiple sets of bidirectional buck–boost soft-switching converters in serial connection in order to achieve zero-voltage switching (ZVS) and zero-current switching (ZCS) so that when the charge/discharge power is above 150 W, the converter efficiency can be increased by 3%. The voltage and current signals from the battery are captured and input into the digital signal processor (DSP) to establish an equalizing charge/discharge control rule. For the output voltage control of the bidirectional buck–boost soft-switching converter, the dynamic mode is derived by first using the step response at chosen operating point, then quantitatively designing the controller parameters for the converter, so that the output voltage response can meet the pre-defined performance specifications. Finally, actual test results prove that the equalizing charge/discharge time of the quantitative design controller is shortened by more than 10% when compared to the traditional proportional-integral (P-I) controller regardless of charging or discharging; this also proves that the design of the photovoltaic module array with an energy storage system (ESS) that has equalizing charge/discharge controls is valid.