MTPA Cooperative Control Strategy of Double Stator DC-Bias Hybrid Excitation Machine Considering Inductance Nonlinearity

This article proposes a maximum torque per ampere (MTPA) cooperative control strategy for a double stator dc-bias hybrid excitation machine (DS-HEM) considering inductance nonlinearity. The proposed DS-HEM uses integrated windings and double stators to improve the torque density, efficiency, and flux regulation capability. Moreover, the proposed MTPA cooperative control strategy considering inductance nonlinearity can achieve high torque and lower copper loss. First, the configuration and drive system of the proposed machine is introduced and a mathematical model of the proposed machine is established, then the proposed MTPA cooperative control strategy considering two dimensions of the armature current and dc-bias current is calculated by using the Lagrange extremum method. Besides, the inductance nonlinearity is also considered by establishing the quadratic polynomial model. Finally, a prototype of the proposed machine is fabricated, and various experiments are conducted to validate the accuracy and effectiveness of the proposed method. Compared with conventional current control strategies, the proposed MTPA cooperative control strategy can generate a larger output torque and lower copper loss.