Assisted Dual-Power Transmission of Bipolar DC Microgrid Using Idle Open-Winding PMSM Drives

The voltage unbalance and instability of bipolar DC microgrid affect the service life of electrical equipment. The integration method of power transmission on the load side can both accurately adjust the load voltage and save costs. However, most methods are functionally limited, which makes it difficult to balance and stabilize voltage simultaneously. If the existing integration method are used to ensure power quality, the coordination among multiple idle motors or the method of adjusting topologies repeatedly is required, which makes the system more complex and less efficient. In this paper, a dual power transmission multiplexing (DPTM) system is proposed, where the dual functions, voltage balance and energy storage are integrated into the open-winding permanent magnet synchronous motor (OW-PMSM) drive. The DPTM system can simultaneously balance voltage and store energy in case of an idle motor. Besides, auxiliary current reversal (ACR) and auxiliary task mixed assignment (ATMA) algorithms with the residual winding are proposed, which can adapt to the changes of the system voltage and switch tasks online. Its effectiveness under different operation conditions is confirmed experimentally on a 1 kW OW-PMSM drive.