Design and Analysis of a New Hybrid Excited Doubly Salient Machine Capable of Field Control

A new stator hybrid excited doubly salient (HEDS) machine with a special saturated magnetic bridge is presented, which combines the advantages of permanent magnet machines with the possibility of controllable magnetic flux by auxiliary DC field windings. The design details and analysis of a 12/8-pole HEDS machine has been presented. The capability of flux control is obtained by using finite element analysis (FEA). In addition, an overall assessment on the influence of the DC field winding is also carried out, in which the relationship between the flux weakening ability and the extended speed range in constant power operation is deduced for the first time. A 12/8-pole HEDS motor has been built for evaluation. Experimental results of the prototype machine are given to verify the theoretical analysis. Both experimental results and FEA show that the proposed machine not only offers the advantages of a doubly salient permanent magnet machine, but also a special ability of the flux control, which is essential for electric vehicle (EV) applications.