Increase in Efficiency of PMSM Drive Using Supercapacitor Storage

In this paper, verification of the efficiency increase of the regulated motor drive with Permanent Magnet Synchronous Machine (PMSM) was performed, using a supercapacitor as an energy storage unit. The supercapacitor is connected to the inverter's DC bus via a three-level DC/DC converter. The supercapacitor is intended to accumulate energy when the drive is in generator mode and to supply the drive while in motor mode. In this way, the application of a bidirectional back-to-back converter for grid connection is not required and a diode rectifier can be used instead. The increased efficiency of a solution with supercapacitor-based energy storage is verified by comparison to low-cost alternatives with a braking chopper. Solutions utilizing supercapacitor storage units significantly reduce the power consumption from the grid.