Assisted Voltage Stabilization and Balancing of Multistructured DC Microgrids Using Idle EV PMSM Drives

Existing solutions to address bus voltage fluctuations and bipolar imbalance in dc microgrids (DCMGs) often face challenges such as high cost, limited functionality, and excessive complexity. In response to these issues, this article proposes a repurposed topology based on electric vehicle (EV) motor drive systems, which integrates voltage stabilization and bipolar balancing functions for unipolar DCMG (UDCMG), asymmetric common-ground DCMG (ACGDCMG), and bipolar DCMG (BDCMG), along with its driving functionality. The proposed solution leverages relays to reconfigure the inverter of an idle permanent magnet synchronous motor (PMSM), adding only relay modules to the EV PMSM drive system. This avoids the added size and cost that would result from introducing additional power devices or inductors. The designed control strategy actively regulates power flowthrough phase current modulation. In addition to voltage stabilization, it can also independently achieve either stabilization or balancing of bipolar bus voltages, or simultaneously perform both functions as needed. Finally, experimental validation based on a 1 kW PMSM drive system demonstrates the effectiveness of the proposed topology in various applications, confirming its ability to stabilize and balance bus voltage under different operating conditions.