Optimal Vector Control of Compound Structure Permanent Magnet Motor for Hybrid Electric Vehicles

The compound-structure permanent-magnet synchronous machine (CS-PMSM) system is a novel drive system used for hybrid electric vehicles (HEVs). In this paper, firstly, the mathematical model of the CS-PMSM motor is examined in detail, and then the control strategy of the CS-PMSM is investigated and established. The CS-PMSM is composed of two permanent magnet synchronous motors: a Double Rotor Machine (DRM) and a Stator Machine (SM). Different control strategies are applied for the two machines. According to their special structures and applications, the DRM performs the torque control, and the SM carries out the speed control. The DRM implements the id=0 control, while the SM carries out the maximum torque per ampere control during the constant torque region, and flux weakening control during the constant power region. Secondly, the direct torque control method is investigated and applied for both machines. The feasibilities of the vector control and direct torque control methods are both validated by the simulation results in the MATLAB/SIMULINK, and these two methods are further compared. The optimum control methods are finally established for the DRM and SM and also the selection of the optimal number of turns for the stator is considered.