Microgrid-Connected Bidirectional Battery Charger Paired with Solar PV in Net-Zero Energy Buildings

A Real-time Controller Hardware-in-the-Loop testing is discussed to validate the versatile DC microgrid control functionalities. Integrating various distributed energy resources and loads alongside energy efficiency requirements for future smart buildings presents interdisciplinary dynamic interactions as recently outlined in relevant distribution systems standards, e.g., IEC 6034-4-41 and NPR 9090. The bidirectional energy exchange for net-zero energy building demands seamless energy management and control solutions. This paper addresses the development of a real-time controller for a standalone DC microgrid use case with solar PV and battery energy storage integration to supply residential loads. The proposed DC microgrid is implemented via OPAL-RT 4610 simulator and RT-LAB tool using switching equivalent circuits for power electronic converters. The solar PV and battery control loops for the used bidirectional dual-active bridge converter are implemented in a DSP TMS320F28335 board. For seamless plug-in and plug-out of distributed energy resources, adaptive tuning of the duty cycles is included in the bidirectional power converter control to operate under a wide soft-switching range and reduced circulating current for the battery pulse charging. Comparative performance analysis of the experimental results is discussed for the testing use case during steady-state and transient operations to verify the proposed control design.