Current Decoupling Model Predictive Control of a Leakage Flux Controllable PM Motor in Virtual Flux Reference Frame

The leakage flux controllable permanent magnet (LFC-PM) motor, which uses intentional magnet leakage flux paths cross-coupled with the q-axis flux paths to realize flux regulation, has been proposed recently and has received widespread attention for traction applications. Yet, the dual function of q-axis current, including flux regulation and torque generation, along with the resulting parameter variation caused by the controllable leakage flux, is one of the main barriers to its control and widespread application. To overcome this barrier, based on the model predictive current control, this article proposes a current decoupling control for the LFC-PM motor. The contribution of this paper is developing a virtual flux reference frame concept where the mathematic model and the optimal current assignment are deduced. On this basis, the predicted parameters can be obtained more accurately, which can suppress the disturbances and low efficiency caused by the mismatched parameters in the process of flux regulation. The proposed decoupling control is validated and compared with the traditional maximum torque per ampere methods. The effectiveness of the proposed control strategy is validated by means of experimental results on a test rig with a 3-kW leakage flux controllable PM motor.