International Journal of Applied Electromagnetics and Mechanics - Volume 72, issue 1

Authors: Liu, Xin | Zhang, Yuting | Wang, Xiaoyuan

Article Type: Research Article

Abstract: Permanent magnet toroidal motor (PMTM) is a novel spatial motor that integrates toroidal drive system and permanent magnet synchronous motor. The unbalanced magnetic pull (UMP) with planet rotor eccentricity is the main cause of vibration in PMTM. In this paper, the analytical model of magnetic field with planet rotor eccentricity is established with the consideration of magnetic flux leakage. The calculation results of eccentric magnetic fields are compared with simulation results of finite element model. Based on the Maxwell tensor method, the analytical model of UMP with planet rotor eccentricity is established. The changes of UMP with initial eccentricity are …obtained. The UMP is analyzed with the effects of eccentric distance and angle. The transient variations of UMP are discussed with different eccentric situations respectively. In addition, both simulation and calculation results for UMP have a good agreement, which verifies the validity of analytical model. Show more

Keywords: Toroidal motor, rotor eccentricity, magnetic field, UMP

DOI: 10.3233/JAE-220025

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 72, no. 1, pp. 1-17, 2023

Authors: Sriwannarat, Warat | Fernando, Nuwantha | Seangwong, Pattasad | Siritaratiwat, Apirat | Khunkitti, Pirat

Article Type: Research Article

Abstract: Machine ratio adaptation of a dual-PM modular doubly salient permanent magnet machine (DPM-DSPM) was proposed to improve the torque characteristics. An optimization design process was examined. Essential machine indicators were investigated to obtain an optimal machine ratio. It was found that p = 4 and a 0.8 rotor pole width ratio of the DPM-DSPM produced the best essential machine indicator that provided the appropriate magnetic flux path and high flux regulation quality. Then, the DPM-DSPM with an optimal machine ratio was investigated based on open-circuit and on-load tests and then compared to a reviewed DPM-DSPM. The results, based on 2-D …finite element analysis, verified that the optimal proposed DPM-DSPM had better torque characteristics. In particular, the optimal proposed structure produced 35.04% higher electromagnetic torque with 61.75% lower ripple torque than the review structure. Therefore, an optimal machine ratio for a DPM-DSPM can be beneficial in solving industrial machine problems, especially noise reduction from vibration. Show more

Keywords: Machine ratio, split ratio, rotor pole width ratio, dual-PM modular, doubly salient permanent magnet machine

DOI: 10.3233/JAE-220047

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 72, no. 1, pp. 19-33, 2023

Authors: Li, Zequn | Li, Desheng | Guo, Benzhen | Zhao, Tong

Article Type: Research Article

Abstract: This paper proposes an electromagnetic damping generator (EDG), which is a novel downhole generator for the rotary steerable system (RSS). The EDG is designed to solve the problem of unstable voltage output by the RSS generator. The generator is designed by integrating a traditional generator and an eddy current retarder (ECR). The system converts the excess kinetic energy of the EDG rotor into heating energy by the principle of eddy-current braking and resistance heating. The electromagnetic finite element models of the generator part and ECR part are established and solved by computer. The voltage and torque generated by the generator …part and the braking torque of the ECR part are predicted. In the bench test, When the input power is 2537 W < P input < 3304 W, the EDG is able to output 300.8 V. When the input power is 3304 W, the output voltage of the ordinary generator is 346 V. The EDG can be adjusted by a decrement of up to 45.2 V to output the rated voltage. The problem of generator output voltage instability in the RSS is solved when mud flow is unstable. Show more

Keywords: Generator, ECR, torque, power, voltage

DOI: 10.3233/JAE-220256

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 72, no. 1, pp. 35-52, 2023

Authors: Fan, Xinyu | Xie, Chengzhi | Zhu, Zhibing | Li, Yang

Article Type: Research Article

Abstract: As an important actuator component, the electromagnetic linear actuator has a significant impact on the performance of fully flexible variable valve trains. Aiming at the shortcomings of the conventional moving coil electromagnetic linear actuator (MCELA) with low force density and insufficient end-passive self-holding ability, a novel compound electromagnetic linear actuator (CELA) integrating the advantages of MCELA and the moving iron electromagnetic linear actuator (MIELA) was proposed in this work. The CELA has two operating modes, including single drive mode and cooperative drive mode, and its loss variation is different from that of the single MCELA or MIELA. Firstly, the current …and displacement curves under different operating modes were obtained through experiments, which were then used as the excitation source to quantitatively analyze the copper and iron losses under different working conditions by means of 3D finite element simulation. The loss distribution and ratio of CELA under typical operating conditions were discussed in detail. The effects of stroke and valve opening duration on CELA losses were analyzed. The results show that there are significant differences in the loss variation rules between the two operating modes, the losses increase as the working stroke increases in single drive mode. In the cooperative drive mode, the losses are much greater than in the single drive mode, with the losses decreasing in the initial stage and then increasing as the stroke increases. None of the valve opening durations had a significant effect on losses. This study provides a reference for loss studies of other novel electromagnetic linear actuators. Show more

Keywords: Compound electromagnetic linear actuator, loss distribution, iron loss, operation mode

DOI: 10.3233/JAE-220185

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 72, no. 1, pp. 53-68, 2023

Authors: Wang, Huanmin | Chen, Jing | Yuan, Xunfeng | Chen, Yao | Zhang, Hui

Article Type: Research Article

Abstract: Electric vehicle (EV) wireless charging technology has recently attracted a lot of attention and has a broad potential for commercial application development. A fundamental performance indicator of wireless charging systems is efficient transmission. Magnetic coupling mechanism design and circuit parameters have the greatest effects on the transmission efficiency of the system. In this study, the output power and efficiency of the wireless power transfer (WPT) circuit were theoretically computed based on the LCC-type resonant network. Simulation studies demonstrate that the transmission efficiency and output gain deviate significantly from the expected value when circuit parameters are changed. To improve transmission efficiency, …the optimal impedance configuration was created using a semi-controlled rectifier circuit. Based on electromagnetic field theory and equivalent magnetic circuit model, a new contactless transformer structure was optimized and created, and the new contactless transformer had a higher coupling coefficient. The coil offset had a greater impact on the transmission efficiency. The results indicate that within a certain distance, the coupling coil offset had no impact on transmission efficiency, and beyond that distance, the transmission efficiency was almost non-existent. Both the feasibility of the practical verification and the accuracy of the theoretical study were tested using a low-power wireless charging experimental setup. This paper provides design guidelines for wireless charging systems using circuit parameter sensitivity analysis and contactless transformer optimization design. Show more

Keywords: Wireless charging, parameter sensitivity, contactless transformer, electric vehicle

DOI: 10.3233/JAE-220084

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 72, no. 1, pp. 69-86, 2023

Authors: Wang, Hujun | Gao, Zhongquan | Meng, Yuan | Li, Yan | Zhang, Qiang

Article Type: Research Article

Abstract: When the ferrofluid is used to seal liquid, the relative movement between the ferrofluid and the sealed liquid causes the stability problem of their interface, and the sealing performance is poor. However, the spiral and the spiral sleeve of the spiral labyrinth seal interact with the sealed liquid to make it reverse flow to prevent leakage when the shaft rotates. In order to improve the performance of rotary ferrofluid seal, the ferrofluid-spiral combined seal structure and the ferrofluid-spiral labyrinth combined seal structure are designed. A combined seal test-bench is built. The pressure resistance experiments and seal life experiments of ferrofluid …seal and two type of combined seals are carried out. The theoretical and experimental results show that the sealing performance of the ferrofluid-spiral labyrinth combined seal is better than that of the ferrofluid-spiral combined seal ferrofluid seal. Ferrofluid-spiral labyrinth combined seal can not only solve the failure problem of ferrofluid seal at high speed, but also solve the leakage problem of spiral seal at shutdown and low speed, so as to achieve a more stable sealing effect at different speeds. The higher the speed is, the better its sealing performance is. Show more

Keywords: Ferrofluid seal, spiral labyrinth seal, combined seal, pressure resistance, seal life

DOI: 10.3233/JAE-220228

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 72, no. 1, pp. 87-101, 2023