Independent torque control of two rotors of an axial-flux PMSM with contra-rotating rotors using a single inverter

This paper investigates an independent torque control method for the two rotors of an axial-flux PMSM with contra-rotating rotors, which is treated as two conventional PMSM connected in parallel, using a single inverter under unbalanced loads condition. Meanwhile, a dynamic master-slave control is implemented under balanced loads condition to avoid the singularity existed in the independent torque control method. A scheme to switch different control strategy between balanced loads condition and unbalanced loads condition is adopted to guarantee a smooth transition. The simulation and experimental results confirm the correctness of the control thinking.