An efficiency optimized controller for a brushless DC machine, and loss measurement using a simple calorimetric technique

This paper describes the design, construction and testing of an efficiency optimised controller for a purpose designed axial flux permanent magnet machine. The testing and measurement is carried out using a new, simple, indirect calorimetric technique. This technique is very inexpensive, and is capable of very high accuracy. In this paper losses in the range of 4 to 34 W are measured with errors of approximately 0.1 W, while the controller is processing power of up to 1 kW. Further refinements to the technique are introduced and discussed