Single Look-Up Table Creation Method for Copper-Loss Minimization in a Wound-Field Synchronous Motor

Wound-field synchronous motors (WFSMs) allow control of the field current, resulting in numerous combinations of stator d-q axis current and field current capable of producing the same torque. In addition, changes in the d-q axis current and field current cause nonlinear variations in the inductance. This paper proposes a method to control a WFSM using a current combination that outputs maximum torque with minimum copper losses while considering variations in the inductance. The proposed method controls the WFSM by creating a single look-up table (LUT) through experimentation, accounting for inductance variations due to changes in current while also reducing memory occupancy. In addition, since the LUT is created with current combinations that minimize copper losses, WFSM can be controlled with minimum copper losses. This paper describes the method and sequence for creating the proposed single flux-torque LUT and verifies the proposed method through experimental results.