Systemic Optimization of Brushless Electrically Excited Synchronous Motors Based on Magnetically Coupled Resonant Wireless Power Transfer

Brushless rotor excitation using wireless power transfer (WPT) can greatly enhance the reliability of electrically excited synchronous motors (EESMs) by eliminating brushes and slip rings. However, the operational performance of brushless EESMs (BLEESMs) is limited by the inefficient combination of WPT devices and EESMs. Most studies focus on the component level to optimize the design of either motor or WPT device, rather than address the system level to achieve optimal system performance. This article presents a systemic approach for design optimization of BLEESMs based on magnetically coupled resonant WPT (MCR-WPT). Key factors limiting the efficiency and power capacity of BLEESMs are analyzed and identified from the perspective of MCR-WPT and EESM. Second, a multiobjective optimization model and design environment for MCR-WPT BLEESM are established, and the mutual inductance change rate is introduced as the evaluation condition for the optimization results. Then, a BLEESM prototype model is designed and the MCR-WPT works at optimal transmission efficiency. The effectiveness of the proposed systemic approach is confirmed by numerical simulation and validated by experimental test results.