An improved dynamic performance of bidirectional SEPIC-Zeta converter based battery energy storage system using adaptive sliding mode control technique

Charging/discharging system based on zeta/sepic converter and a sliding mode controller for dc bus voltage regulation

“…One option to perform such a balance is to regulate the dc bus voltage to a reference value, which is particularly important for MGs operating in island mode. Therefore, the dc bus voltage regulation is the main objective of the ESD charging/discharging system's controller [5][6][7][8][9]. On the one hand, when there is an excess of load with respect to the generation the dc bus voltage tends to reduce; then, the charging/discharging system extracts power from the ESD (i.e.…”

“…Moreover, in some ESD technologies, the voltage significantly varies depending on the state‐of‐charge, then the ESD voltage may be lower, equal, or greater than the dc bus voltage [14, 19]. Hence, a bidirectional step‐up/down converter is a flexible solution that can be applied when the ESD voltage is lower, equal to, or greater than the dc bus voltage [5, 6, 9, 10, 14, 19, 24, 25].…”

“…Although there are different step‐up/down converters [19, 26] in the literature, buck–boost [9, 12, 14, 18, 27] and sepic/zeta [6, 24, 25] have been used to connect an ESD to a dc bus and to regulate its voltage. However, the zeta/sepic provides some advantages over the buck–boost since, unlike the buck–boost, the zeta/sepic output voltage has the same polarity of the input voltage, and it provides a continuous output current, which reduces the voltage ripples in the dc bus.…”

“…To overcome the output voltage inversion, sepic/zeta converter has been implemented to couple an ESD to a dc bus [6, 25]; however, this converter does not solve the problem of the discontinuous current at the dc bus side. In [25], the authors propose an algorithm that uses the ESD's state‐of‐charge to define the operation mode.…”

“…In [25], the authors propose an algorithm that uses the ESD's state‐of‐charge to define the operation mode. On the other hand, a PID type SMC controller to regulate the dc bus for charging and discharging modes is proposed in [6]. The controller regulates the dc bus voltage in discharging mode (sepic) and the ESD voltage in charging mode (zeta) with a single SMC.…”