Post-processing-based Flux-weakening Control of Variable Flux Reluctance Machines

This paper introduces a novel post-processing-based flux-weakening control method for variable flux reluctance machines. The proposed method achieves high-efficiency operation at elevated speeds by determining the optimal values for both ac- and dc-field currents together with the commutation angle. The nonlinear electromagnetic characteristics of the benchmark variable flux reluctance machine are simulated to calculate torque production and back-EMF voltage in relation to the excitation parameters, namely, ac current, dc current, and commutation angle. The control algorithm determines the optimal values for these parameters to achieve the desired torque and speed references while minimizing the total excitation current.