This paper investigates the efficient robust design optimization of a five-phase permanent magnet (PM) hub motor for electric vehicles. Besides the requirement of high-performance, like high torque density, low torque ripple and efficiency, fault-tolerant operation capability is also considered in the design optimization. To ensure that the motor performance is not sensitive to the variations of manufacturing tolerances, robust design optimization is employed to the investigated motor. To improve the fault tolerant capability of the motor, the motor performances under fault operation is also considered in the optimization. A Fuzzy-based sequential Taguchi robust optimization method is proposed to improve the comprehensive performance and save computing time. The proposed method is efficient because it holds the advantages of Taguchi method, fuzzy theory, and sequential optimization strategy. The motor performance is improved significantly by using the proposed method. Experimental results verify the accuracy of the model used in this study.

In this paper, a new nonlinear lumped parameter equivalent circuit model is proposed to calculate the core losses of a novel 16/10 segmented rotor switched reluctance motor (SSRM) for belt-driven starter generators. The model investigates the hysteresis, eddy current and anomalous losses by using the method of energy conservation. Four parameters are introduced in the proposed model to consider the effects of saturation and leakage flux in SSRM. They are the incremental leakage inductance, the incremental equivalent winding resistance, the incremental magnetizing inductance, and the incremental equivalent core-loss resistance. This model can overcome the hysteresis effects of winding resistance and leakage inductance on the current, and improve the accuracy of the parameters. To illustrate the advantages of the proposed model, an experiment platform is developed. Experimental results show that the proposed model can significantly improve the calculation accuracy of core losses of the SSRM. The accuracy is better than the conventional Epstein frame method. The proposed core-loss model and analysis method can be applied to other kind of switched reluctance motors.

In this paper, a permanent magnet synchronous machine (PMSM) for electric vehicles (EVs) is studied. Since EVs need to face some low speed road conditions, it is necessary to drive the machine to maintain a stable torque at low speed. The stator skew slot is often adopted to reduce torque ripple; however, it declines the output torque at same time. Besides, the difference between positive rotation performance and negative rotation performance which caused by the skew slot are often ignored. Through the finite element analysis (FEA), the cogging torque and dynamic performance of the PMSM at different skew angle are studied. Moreover, the different influence of slot skew angle on positive and negative rotation performance is studied. Then the optimum skew angle of the PMSM is studied through com-prehensive consideration. Finally, the cogging torque of the pro-totype is verified to be less than 2 N.m. through the experiment.

In this paper, an improved direct instantaneous torque control (DITC) based on adaptive terminal sliding mode control (ATSMC) is proposed to suppress torque ripple and enhance the anti-interference ability for switched reluctance motors (SRMs). The proposed speed controller used in the outer loop of DITC is based on the rate of change in load torque. The state of the system converges quickly to the equilibrium point and realizes fast output of the given torque without known disturbance upper bound. Moreover, a novel reaching law is proposed to reduce torque ripple and startup time. The stability of the adaptive terminal sliding mode motion is verified by using the Lyapunov function. The improved DITC system is implemented on a 16/10 segmented-rotor SRM. Compared with sliding mode control and terminal sliding mode control, the proposed ATSMC in DITC system behave better performances in aspects of the speed and torque response, anti-interference ability, robustness, and torque ripple suppression. Simulation and experimental results are given to verify the effectiveness of the improved DITC.

Axial flux machines have huge potential in direct-drive operations such as In-wheel drive operation due to the characteristics of high torque density and short axial length. However, the design optimization of axial flux machines was limited by the lack of accuracy magnetic circuit model. In this paper, a spoke-type axial-flux permanent magnet synchronous machine (Spoke-type AFPMSM) is designed and an efficient optimization method for axial flux structure is proposed. The proposed optimization method improves the efficiency of the optimization design by using a 2-D equivalent finite element model and multilevel optimization strategy. The parameters without end effects will be optimized by a 2-D equivalent model and the parameters with end effects will be optimized by a 3-D model. In this way, the number of finite element nodes required for optimization calculation can be minimized. Besides, the multilevel strategy and response surface optimization method are also adopted to further improve the efficiency of the optimization. The proposed method improved the cost, efficiency, and torque of the AFPMSM significantly, and some other constraints are also considered in the optimization progress. Finally, experimental results based on a prototype are provided to validate the performance of the proposed AFPMSM. The proposed method can be applied for other design optimization of axial flux operations.