Loss minimization control of vernier reluctance machines with DC field windings in stator

An advanced control strategy of a variable flux vernier reluctance machine is proposed to improve efficiency and load capacity in this paper. Distinguished with traditional vernier machines, this machine has a novel doubly salient structure with DC field-exciting windings in stator slots. Losses of this machine are produced in both three-phase armature windings and DC windings, which occasionally leads to low efficiency. In response, a loss-minimizing control strategy for the purpose of increasing efficiency in the whole speed range is proposed. Mathematical equations of this machine, including voltage equations and flux linkage equations, are presented based on synchronously rotating dq-axis coordinate system. The control strategy in high speed situation is also presented. The results of simulation in MATLAB SIMULINK are illustrated in this paper, where the effectiveness of the control strategy is proved by comparing the efficiency of this machine with traditional control strategy and with loss-minimizing control strategy.