Performance Improvement of Brushless Exciter for Aircraft Wound Rotor Synchronous Machine Based on Magnetic Slot Wedge

Brushless excitation system makes aircraft Wound Rotor Synchronous Machine(WRSM) obtain good reliability and maintainability, but it also suffers from the disadvantages of slow dynamic response and relatively low excitation efficiency. This paper proposes a low-cost method to improve dynamic response speed and efficiency of brushless excitation system by adding magnetic slot wedges(MSW) between the stator poles of Main Exciter(ME) without changing the structure of ME. By Finite Element Analysis(FEA) simulation, MSW will increase the commutation reactance of ME, which is beneficial to improving dynamic performance. Moreover, MSW weakens the air gap flux density harmonics, leading to significant reduce in core loss of ME. A 12kVA generator prototype is manufactured and tested. The test results are consistent with FEA simulation results, which proves the accuracy of FEA model and confirms the performance improvement of ME by MSW.