Efficiency Optimization of a Permanent-Magnet Hybrid Brushless Machine Using DC Field Current Control

This paper proposes a new efficiency optimization approach for a new kind of permanent-magnet hybrid brushless (PMHB) machine. The key is to propose the self-searching control (SSC) for the PMHB machine in such a way that the input power at the given load and speed can be progressively minimized by tuning the dc field current. A loss analysis of the machine is given to justify the use of dc field current as the control parameter. Detailed experimental results confirm that the proposed approach can effectively accomplish the desired efficiency optimization.