An ultracapacitor-based energy storage system design for high power motor drive with dynamic real power compensation and harmonic cancellation

This paper presented an ultracapacitor (UC)-based energy storage system (ESS) design for high power motor drive application. The ESS is cascaded with three-phase multilevel motor drive inverter to provide not only harmonic cancellation but also real power compensation during transients and steady states. An active power control strategy was developed to implement desired power flow modes during acceleration, deceleration, and steady states by allocating appropriate real power between main inverter cell and ESS inverter cells. The proposed control strategy also allows the smooth power transition between operating modes. In addition, an auxiliary control scheme was developed to coordinate the active power control and voltage balancing of UC. Finally, the developed control is integrated with the motor drive vector control to improve the motor drive performance. Both simulation and experimental results were presented to verify the validity of proposed ESS design.