Improvement of power generation performance in a doubly salient permanent magnet generator with a capacitive energy recovery converter

In order to improve the power generation performance of a doubly salient permanent magnet generator (DSPMG), this study proposes a new converter called capacitive energy recovery converter (CERC), together with the corresponding control strategy. The CERC is composed of controllable devices, uncontrollable devices, and an energy storage circuit. The control strategy has been designed based on analysis of the electromagnetic characteristics of the DSPMG. With the proposed control strategy, the winding current of each phase can be controlled and increased separately, thus yielding large negative electromagnetic torque against the prime mover in a complete electric cycle. At the same time, the excitation sources are independent of the load part. As a result, power generation performance of the DSPMG with CERC is improved compared to that with a traditional three-phase full-bridge converter. A multi-objective optimisation problem is formulated to find the optimal turn-on and turn-off angles of two systems, which are used as control parameters in this comparison. Besides the lower voltage and torque ripples, the dynamic and fault-tolerant performance of the DSPMG with CERC is also superior. Both simulations and experiments have been conducted to verify the validity of the proposed converter and the control strategy.