Performances for a synchronous machine with optimised efficiency while wide speed domain is attempted

A combined control technique is proposed to improve the efficiency of an in-wheel motor with outer rotor for traction system. The double excited motor has permanent magnets and field winding as excitation sources. The ´combined control strategy´ employed in the extended speed operation is based on an alternate field-weakening technique by negative d-axis current injection and by adequately feeding the auxiliary field winding, respectively. The alternate technique proposed is detailed and the computed results are obtained using 2D finite-element method analysis, and the MATLAB/Simulink package stand by to validate it. The tests will prove the expected speed gain and the validity of the machine´s topology.