This paper describes a study on the improvement of the dehydration performance of the conventional washing machine model. Recently, as interest in improving the dehydration performance of washing machines has increased, the need for a study on a high-speed electric motor has emerged. However, this conventional spoke-type PMSM has difficulty in speeding up due to the following problems. First, field weakening control is indispensable for high-speed operation of an electric motor. This control method is a big problem in causing torque drop and irreversible demagnetization of the motor. Moreover, the centrifugal force increases during high-speed operation, which adversely affects the stiffness of the motor. Therefore, in this paper, a new rotor shape of spoke-type PMSM was proposed to solve the above problem.

The spoke-type permanent magnet synchronous motor (PMSM), which is a general ferrite magnetic flux-concentrated motor, has a low portion of reluctance torque at the total torque magnitude. Therefore, as a way to increase the reluctance torque, there is a double-layer spoke-type PMSM that can maximize the difference in inductance between the d-axis and the q-axis. However, in the double-layer spoke-type PMSM, cogging torque, torque ripple, and total harmonic distortion (THD) increase with reluctance torque, which is the main cause of vibration and noise. In this paper, a method is proposed that provides the same effect as skew without dividing stages of the permanent magnet by dividing the core of the rotor into two types so that it is easy to manufacture according to the number of stages, unlike extant skew methods. Based on the method, the reduction in cogging torque and THD was verified by finite element analysis (FEA).

Permanent magnet synchronous motors (PMSMs), with their high power density, high efficiency, and thermal stability, are widely used nowadays. PMSM magnets are composed of rare earth elements. However, rare earth elements are subject to severe price fluctuations because of their limited availability and the monopoly of some countries. Therefore, extensive research on magnets devoid of rare earth elements has been conducted recently. Although a magnet devoid of rare earth elements has a high irreversible demagnetization rate at high temperatures owing to its low coercive force, an irreversible demagnetization improvement process is proposed in this paper to compensate for this disadvantage. This process analyzes the contribution of the magnet’s back EMF (electromotive force) using the flux linkage equation, which does not change with time. Next, the location of irreversible demagnetization is moved to a position with a low contribution to the back electromotive force. Consequently, even if irreversible demagnetization occurs at the same size, the irreversible demagnetization ratio is reduced. The proposed process can minimize irreversible demagnetization while maintaining performance.

Recently, the demand for miniaturization in various applications within the automotive and industrial sectors has been steadily increasing. Consequently, there is a growing need for research and development of the Axial Flux Permanent Magnet Synchronous Motor (AFPMSM), which is advantageous in thin structures. However, in conventional AFPMSMs, the variation in tooth thickness from the inner diameter to the outer diameter of the stator poses significant manufacturing challenges. To address this, a Coreless AFPMSM, which does not use a stator core, can be employed. However, this design introduces its own challenges, including significantly increased magnetic reluctance due to the absence of teeth and the need for robust support structures for the stator windings. This paper proposes a solution to these issues by utilizing a Printed Circuit Board (PCB) substrate as the stator in a PCB Stator Motor. It describes the design process for the coil pattern of the PCB stator. Using conventional winding methods, the coil pattern layout of the PCB stator is designed, effective conductors are arranged and connected, and the PCB stator is completed. The PCB stator is then applied to an AFPMSM, with Halbach permanent magnets used to improve power density. The design is carried out using 3D finite element analysis (FEA), and the proposed model is validated by comparing the back electromotive force (EMF) under no-load conditions with that of the manufactured model.

In spoke-type permanent magnet synchronous motors (PMSMs), an asymmetric rib structure has been investigated as a method to reduce cogging torque. However, such rotor asymmetry tends to an increase in the axial force, which limits its applicability in precision and low-vibration systems. To overcome this limitation, this study proposes a new motor design method that introduces a skew factor as an additional design variable. The skew factor, defined as the ratio of the skewed region to the total stack length, enables simultaneous control of cogging torque and axial force by adjusting the degree of asymmetry along the rotor stack. Using parametric modeling and finite element analysis (FEA), the combined effects of the asymmetric rib and skew factor were investigated, and an optimized motor structure achieving balanced cogging torque and axial force characteristics was derived. The proposed design approach provides an effective method for simultaneously considering cogging torque and axial force in spoke-type PMSMs.

As the electrification of the automotive industry accelerates, the importance of small-scale motors used in applications such as HVAC systems and water pumps is growing. To design small motors that exhibit high efficiency and high output within limited spaces, applying axial flux motors (AFMs) instead of conventional radial flux motors (RFMs) can maximize the power density within the same volume, offering advantages in both weight reduction and miniaturization. This study proposes an optimized end-turn layout design to mitigate back-EMF imbalance in AFMs utilizing PCB stators. Optimization results demonstrated that the structure employing a non-adjacent end-turn layout with equalized average end-turn heights (BCAACB type) exhibited the best performance in terms of average resistance and phase resistance variance, effectively mitigating back-EMF imbalance. The validity of the optimized end-turn structure was verified through finite element analysis (FEA). The analysis confirmed that the motor’s back-EMF balance was improved, and the magnitude of phase resistance was reduced. This reduction led to lower copper loss, thereby increasing overall efficiency. Furthermore, the variance in resistance for each phase was minimized, resulting in enhanced electrical balance. The results of this study are expected to contribute to enhancing the applicability of PCB stators in small motor design.