Sizing equation analysis for field controlled PM machines: a unified approach

In this paper, the sizing equation analyses are presented for two different radial and axial flux field controlled PM machines. These types of machines have two sources of excitation which allows one to easily control the airgap flux. Variable flux component provided by the field winding and fixed flux component obtained from PM converge into the airgap so that an additive or subtractive effect can be achieved over a wide range such that the machine speed range can be increased. A detailed analysis is made is order to evaluate the performance, power density and efficiency. In addition, guidelines for optimal design of the two machines are pointed out.