A new decoupled control for five-phase in-wheel fault-tolerant permanent magnet motors for electric vehicles

Summary form only given. In recent years, it is a trend that electric vehicles (EVs) employ multiphase permanent magnet (PM) motors because of their advantages such as high efficiency, high power density, and high torque to current ratio. Many control strategies have been investigated for PM motor drives [1-3]. However, due to the multivariable and strong coupling nonlinear system, it is difficult to meet the high requirements of EVs. Hence, the purpose of this paper is to propose a new decoupled control for a five-phase PM motor drive. A novel five-phase in-wheel fault-tolerant PM (IW-FTPM) motor was proposed by authors [4], as shown in Fig.1. It adopts an outer-rotor topology, and can be mounted to the wheel hub directly. The V-shaped inserted PMs are employed on the outer-rotor, which can improve the torque capability of the in-wheel motor. A five-phase single-layer concentrated winding set is adopted among the 20 stator slots. The fault-tolerant teeth which involve the unequal tooth widths are engaged, in order to offer prominent fault-tolerant operation capacity. Since this motor is a multivariable and strong coupling nonlinear system, the key of the control is decoupling and linearization. As shown in Fig.2, this work proposes a new internal model control (IMC) of the motor by using the radial basis function neural network inverse (RBF-NNI) system. The RBF-NNI system is introduced to construct a pseudo-linear system with original system, and internal model controller is utilized as a robust controller. Therefore, the new system incorporates the merits of the IMC and RBF-NNI methods. The dSPACE real-time control platform is developed. Fig.3 shows the simulated responses of both the d-axis current (i_sd) and speed (ω₁) at step inputs both with PID system and proposed IMC-based RBF-NNI system. It can be seen that by using the proposed control strategy, the i_sd and ω₁ are almost successfully decoupled, an- both responses have good dynamic performances. What´s more, the proposed strategy also has strong robustness to load torque disturbance and un-modeled dynamics. The more detailed analysis results, discussions and experimental results will be given in the full paper.