A Line-Commutated Thyristor Bridge Emulated Rotating Power Electronic Converter (LCTEPC) with Mode-Switching Algorithm for Brushless Exciter Applications

Brushless Exciters (BLEs) eliminate the issues associated with brush wear and tear, significantly reducing maintenance requirements and enhancing their reliability in Wound Field Synchronous machines. This paper presents a Line Commutated Thyristor Bridge Emulated Rotating Power Electronic Converter (LCTEPC) as a novel solution for BLE applications. The proposed LCTEPC topology utilizes a minimal number of controlled switches and removes the necessity for a bulky DC-bus capacitor, thereby enhancing the overall reliability of the BLE system. Additionally, the LCTEPC can operate at substantially higher frequencies, enabling the use of a compact rotating transformer and reducing field current ripple. The detailed operation of the proposed topology is presented, along with an algorithm designed to mitigate field current disruptions during mode transitions. To validate the concept, an experimental prototype of the LCTEPC has been developed, and the corresponding test results are discussed.