We designed and analyzed an interior permanent magnet synchronous motor (IPMSM) to prevent irreversible demagnetization of the permanent magnets (PMs). Irreversible demagnetization of NdFeB PMs mainly occurs due to high temperature, which should thus be minimized. Therefore, it is necessary to reduce the eddy current loss in the PM through optimal design. The shape of the rotor core was optimized using finite element analysis (FEA) and response surface methodology. Three-dimensional (3-D) FEA is required for accurate computation of the eddy current loss, but there is huge time, effort, and cost consumption. Therefore, a method is proposed for indirectly calculating the eddy current loss of PMs using 2-D FEA. A thermal equivalent circuit analysis was used to calculate the PM temperature of the optimized model. For the thermal analysis, the copper loss, core loss, and eddy current loss in PMs were estimated and applied as a heat source. Based on the results, we confirmed the stability of the optimum model in terms of the PM demagnetization.

The performance of motors can vary considerably, depending not only on the design but also the manufacturing process. In particular, for motors used in systems wherein vibration and noise are important, the characteristics of the motors change according to the manufacturing method; hence, it is essential to study the effect of the manufacturing process on the characteristics of motors. In this study, motors with a connected core and segmented core are compared and analyzed; particularly, the motors are intended for use in a brake system. The general strengths and weaknesses of each core type are determined, and the electrical and mechanical properties of the motors are analyzed through finite element analysis (FEA). The motors are applied to an integrated brake system that does not employ a vacuum booster, and motors with each type of core are fabricated and tested to verify their characteristics. Finally, the analysis results obtained using FEA and the test results are compared and analyzed to evaluate the validity of this study.

This article introduces the single winding type selection process for a dual winding (DW) three-phase motor. Unlike the conventional DW three-phase motor design, the proposed single winding type selection process simultaneously considers the mechanical length determined by the single winding type and the motor overheating problem caused by faulty operation for each single winding type. The proposed single winding type selection process consists of four steps. First, all single-winding combinations, the point symmetry dual winding (PSDW), line symmetry dual winding (LSDW), and cross symmetry dual winding (CSDW) for DW three-phase motor are investigated. Second, according to the selected single winding types, the busbar height (BH) required for dual division is designed and compared. Third, the stack length (SL) of motor in the PSDW, the LSDW, and the CSDW obtained through overheat compensation design to avoid the overheating problem in the faulty mode are investigated and compared. In the overheat compensation design, the thermal map utilizing measurement data from the previously developed motor for an integrated electric brake (IEB) system, a radial basis function, an overheat compensation coefficient, and the IEB brake load condition are utilized. Finally, the single winding type of DW three-phase motor is selected as the CSDW by comparing the total motor size. As a result of the DW three-phase motor design, the proposed CSDW can reduce the motor size by 12.0% and 4.2%, respectively, compared with the PSDW and LSDW.

Autonomous emergency braking (AEB) is one of the safety technologies of the integrated electronic brake (IEB) system and is critical to avoiding or mitigating vehicular collisions. In addition, a motor is a significant component of the IEB system for its actuation, and it greatly affects this system’s performance under AEB. Notably, the determination of the IEB system’s motor parameters without considering its performance under AEB will not satisfy its requirements, especially due to this system’s hydraulic and electric complexity. In addition, the IEB system motor’s dynamic characteristics have a significant impact on the AEB performance. They are also closely related to this motor’s parameters, such as flux-linkage, inductance, and resistance. Therefore, this research performs the IEB system’s motor parametric design corresponding to this system’s necessary performance under AEB, using a coupled simulation model composed of this system’s motor and hydraulic subsystems. First, the IEB system’s motor and hydraulic subsystems are modeled in MATLAB/Simulink and AMESim, respectively, and the coupled simulation of these subsystems is performed in Simulink using their models. Second, the respective ranges of the IEB system’s motor parameters corresponding to this system’s necessary performance under AEB are determined from the above-mentioned coupled simulation, and their corresponding motor is designed using a finite element analysis in ANSYS Maxwell. Third, the IEB system’s fabricated, parametric-designed motor is tested for standalone performance. Finally, the IEB system incorporated with the said parametric-designed motor is experimentally verified of its performance under AEB. Meanwhile, the respective simulated and experimental performances of the IEB system under AEB and its parametric-designed motor agree well. This agreement indicates that the IEB system’s motor parametric design presented in this research, based on this system’s coupled simulation model and finite element analysis on this model, is valid.

A conventional dual-winding (DW) motor has two internal windings consisting of a master part and a slave part, each connected to a different electronic control unit (ECU) to realize a redundant system. However, existing DW motors have a problem related to heat generation in both the healthy mode and the faulty mode of the motor operation. In the healthy mode, unexpected overloads can cause both windings to burn out simultaneously due to equal heat distribution. If the current sensor fails to measure correctly, the motor may exceed the designed current density of 4.7 [Arms/mm²] under air-cooling conditions, further increasing burnout risk. External factors such as excessive load cycles or extreme heat conditions can further exacerbate this issue. In the faulty mode, the motor requires double the current to generate maximum torque, leading to rapid temperature increases and a high risk of overheating. To address these challenges, this paper proposes the design of a thermal fault-tolerant asymmetric dual-winding (ADW) motor, which improves heat management in both healthy and faulty modes for autonomous vehicles. A lumped-parameter thermal network (LPTN) with a piecewise stator-housing model (PSMs) was employed to evaluate the coil temperature during faulty operation. An optimal design approach, incorporating kriging modeling, Design of Experiments (DOE), and a genetic algorithm (GA), was also utilized. The results confirm that the proposed ADW motor design effectively reduces the risk of simultaneous burnout in the healthy mode and overheating in the faulty mode, offering a robust solution for autonomous vehicle applications.