Study on the Loss and Efficiency of a Homopolar Inductor Machine

Homopolar inductor machine (HIM) has robust rotor structure, brushless exciting and simple structure, which has been used as a pulsed alternator to charge the capacity. For this machine, the loss and efficiency are the key parameters, which have seldom investigated in the previous paper. Addressing this issue, this paper studied it. Firstly, the characteristic of flux density distribution is investigated. Secondly, an analytic method is established to calculate the eddy current loss of rotor, which is validated by the finite element analysis (FEA). Finally, a prototype machine is tested and the efficiency of HIM is measured. The pulse discharge efficiency and energy distribution are also investigated. Results show that stator core loss mainly exists in stator iron cores and a little exists in the sleeve. The lower the discharge frequency is, the lower the efficiency becomes. The conclusions would be useful for the design and operation of HIM.