In this paper, a multimode design method is proposed for motor design under multiple operation conditions. Based on the driving cycles in electric vehicles, five typical operation conditions and the corresponding five driving modes are determined for the multimode design. To investigate the method conveniently, a flux controllable stator permanent magnet (SPM) memory motor is selected and taken as a design example. In the design process, by using the sensitivity analysis method, the significance of the parameters in various driving modes are evaluated effectively. Based on the motor driving demands, the whole optimization design is divided into three steps, where different optimization method is applied in each step. To verify the feasibility of the multimode design method, the operation performances of the motor in different driving modes are investigated in detail. Finally, a prototype motor is built and tested. Both the simulation and experimental results reveal that the proposed design method can offer an effective design optimization for the flux-controllable SPM memory motor, where multimode operations are indispensable.

In this paper, a variable-saliency-ratio permanent magnet (VSR-PM) motor is designed and optimized considering driving cycles. To satisfy the demands of multi-operation conditions of EVs, a variable resistance is adopted and a new variable-saliency-ratio design concept is proposed to enhance output torque, widen speed range and lower irreversible demagnetization risk effectively. A multi-objective optimization considering driving cycles is proposed, where the design objective of saliency ratio is firstly selected and optimized with multi-objective genetic algorithm (MOGA) method. Then, the operation performances of the motor in different operation conditions are investigated in detail. Finally, a prototype motor is built and tested. Both the simulation and experimental results verify the validity of the proposed method.

In this article, a new controllable leakage flux multilayer barrier permanent magnet (PM) motor is proposed by adopting a new design concept of controllable leakage flux, where the PMs are uniquely placed in the d -axis magnetic circuit of the synchronous reluctance motor (SynRM). Compared to the conventional q -axis PM placement SynRM, the higher PM utilization and better flux-weakening capability can be obtained. For further comparison and verification, both of the controllable leakage flux multilayer barrier PM motor and the motor with traditional q -axis PM setting are designed. In addition, a multiobjective optimization method based on the correlation analysis method is proposed to obtain the optimized output torque and flux-weakening performances. Then, the performances of the two optimal motors are analyzed and compared in detail. Finally, two prototype motors are manufactured and tested. Both the theoretical and experimental analyses verify the effectiveness of the flux-weakening enhancement design and the proposed motor.

This article reveals the flux leakage design and modeling principle of a flux leakage controllable permanent magnet (FLC-PM) machine by considering driving cycles. The key is to obtain the relationship between flux leakage characteristics and multiple operating conditions. Based on the flux leakage controllable concept, an FLC-PM machine with an artfully designed flux leakage region is proposed. The design principle of the machine is investigated by analyzing the magnetic circuit of the machine in multiple operating conditions. The flux leakage factor is introduced to characterize the variable magnetic field in multiple operating conditions. On this basis, the mathematical model of the FLC-PM machine is deduced, and the driving characteristics of the machine are studied in detail. In order to evaluate the presented principle of the FLC-PM machine, a prototype is manufactured for experiments. Through the theoretical analysis and experimental testing, it is verified that the proposed principle is feasible and effective.

In this paper, two new flux-intensifying interior permanent magnet (FI-IPM) motors owing the characteristic of Ld>Lq are proposed for extended operating speed range. The feasible approaches of realizing Ld>Lq are firstly discussed to emphasize rotor flux barrier design. According to the feasible approaches, interior flux barriers and surface flux barriers combined with different PM placements are respectively adopted in this two motors. To verify the proposed approaches and the validity of motors, a comprehensively investigation and comparison between the two motors is carried out, including both electromagnetic performances and mechanical performances. By comparison, a prototype motor possessing lower torque ripple, lower magnetic saturation, wider speed range and more robust mechanical property is manufactured and tested. The experiment results verify the characteristics of the proposed motors and the validity of the proposed approaches in FI-IPM motor design.

This paper proposes a new hybrid permanent magnet (PM)-assisted synchronous reluctance motor, where two types of PM materials of rare-earth PMs and ferrite PMs are employed in its rotor. To reduce the usage of rare-earth materials, a hierarchical design method is adopted in its rotor design, in which the design is divided into two levels: saliency ratio design level and PM usage design level. In saliency ratio design level, proper flux barrier dimensions are confirmed based on the principle of reluctance torque maximization. In PM usage design level, the optimal magnet ratio is first determined according to the relationship of main flux and leakage flux. Then, a tradeoff design is conducted to seek the superior combination of low torque ripple, high efficiency, and high power factor. Finally, for the purpose of validation, the electromagnetic performances of the new designed motor are investigated, including torque characteristics and antidemagnetization capabilities of ferrite.