Minimum-copper-loss control of hybrid excited axial field flux-switching machine

Hybrid excited axial field flux-switching machine (HEAFFSM) with permanent magnets (PMs) and excitation windings in its stator is a novel hybrid excited flux-switching PM machine. The HEAFFSM combines the advantages of the hybrid excited synchronous machine and flux-switching PM machine. In this study, the topology and operating principles of the HEAFFSM are analysed, and the electromagnetic characteristics (including the winding inductances, flux, and cogging torque) are obtained by the three-dimensional finite-element method. On the basis of the vector control method, the mathematical model of the HEAFFSM is deduced, and the operating performance of the HEAFFSM across its entire operating range is investigated. A new minimum-copper-loss (MCL) control strategy for the HEAFFSM drive system, which can operate in both flux-enhancing and flux-weakening conditions, is proposed and compared with the traditional control. The experimental results demonstrate that the MCL strategy maximises the range of speed regulation while minimises the copper loss of the HEAFFSM drive system. Moreover, the flux-regulation capability and high power/torque density of the HEAFFSM are validated.