Control Strategy and Hardware-in-the-Loop Simulation of a DC Microgrid Under the Net Zero Energy Concept

This works presents a control strategy for a dc microgrid intended to operate in both grid-connected and islanded modes with smooth transitions between them. The dc microgrid is composed of photovoltaic (PV) generation, fast Electric Vehicle Charging Station (EVSE), low voltage dc loads, and a Battery Energy Storage System (BESS). All converters are connected into a single 700 V dc bus that interfaces with the ac grid through a
$\mathbf{3}-\phi$
bi-directional ac-dc converter. Moreover, the microgrid operates under the Net Zero Energy (NZE). The proposed strategy comprises primary and secondary control levels. Primary level corresponds to the control of ac-dc and BESS converters considering parallel operation while secondary level to the control of the power exported to grid to achieve NZE operation. The system is validated through Hardware-in-the-loop simulation in the Typhoon HIL 604 platform with the control strategy implemented in a DSP. Real-time simulation results are presented for several operation conditions during normal operation and the transition between the operation modes.