Abstract: In order to extend the speed range for the constant-power motoring mode or the constant-voltage generating mode of the electric machine, a new structure of hybrid excitation machine with isolated magnetic paths (HEIMP) is presented. Its structural characteristics and operation mechanism are detailed. The prototype machine with 12 poles, 18 slots and 2 units is simulated and analyzed with the Ansoft Maxwell 2D finite element (FE) software for its field adjustability, and with the ANSYS FE software for its centrifugal stress, natural frequency and thermal characteristics in order to verify the structural feasibility and rationality of the HEIMP machine. The test on the prototype machine shows the adjustability of the excitation mmf on both directions and the magnetic field in a wide range. Due to the compact, the utilization of its stator iron core and its armature winding is effective, therefore, the HEIMP machine possesses high efficiency. The test results of the prototype machine show good agreement with the FE simulation ones, which verifies the correctness of the multi-domain simulation technique. It solves the technical problems effectively in the accurate characteristics calculation and the design optimization of the new structure HEIMP machine and therefore, promotes its design capability.

Key words: Hybrid excitation, Isolated magnetic path, Multi-domain, Simulation