Investigation of Switching Frequency Effect in Current Harmonic of Slotless Permanent Magnet Synchronous Machine with Voltage Source Inverter
Source abstract
Abstract
Slotless permanent magnet synchronous motors (PMSMs) have recently attracted significant attention for robotic and high-speed machine applications because they eliminate cogging torque and reduce iron loss through the absence of stator teeth. However, removing the stator teeth increases the effective airgap, resulting in extremely low synchronous inductance and introducing electrical challenges such as reduced control stability and increased current harmonics during pulse-width modulation (PWM) operation in inverter drive systems. In this paper, the current harmonic characteristics of a slotless PMSM are investigated with respect to switching frequency. Based on the mathematical model, the effects of switching frequency on a slotless PMSM drive system employing a MOSFET inverter are analyzed. In addition, an experimental setup, including a 700 W slotless PMSM and a MOSFET inverter, is implemented to evaluate the current harmonic characteristics under different switching frequencies of 25 kHz, 50 kHz, and 99 kHz. The total harmonic distortion of current at 99 kHz is reduced by approximately 6.73%p and 3.57%p compared with operation at 25 kHz and 50 kHz, respectively. The experimental results demonstrate the influence of PWM operation on the current characteristics of the slotless PMSM and verify the importance of high switching frequency operation for improving current performance.
Source: crossref · Quality: baseline
Research context
OpenAlex topics: Sensorless Control of Electric Motors · Electric Motor Design and Analysis · Multilevel Inverters and Converters
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
Department of Electrical Engineering, Hanyang University, Seoul 04763, Republic of Korea
Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, USA
References (40)
Show source-provided references
1. A Review on Electric Vehicles: Technologies and Challenges10.3390/smartcities4010022 ↗
2. Un-Noor, F., Padmanaban, S., Mihet-Popa, L., Mollah, M.N., and Hossain, E. (2017). A Comprehensive Study of Key Electric Vehicle (EV) Components, Technologies, Challenges, Impacts, and Future Direction of Development. Energies, 10.10.20944/preprints201705.0090.v1 ↗
3. A Critical Review of Advanced Electric Machines and Control Strategies for Electric Vehicles10.1109/JPROC.2020.3041417 ↗
4. A Comprehensive Review on Structural Topologies, Power Levels, Energy Storage Systems, and Standards for Electric Vehicle Charging Stations and Their Impacts on Grid10.1109/ACCESS.2021.3112189 ↗
5. Charging Schemes for Plug-In Hybrid Electric Vehicles in Smart Grid: A Survey10.1109/ACCESS.2016.2614689 ↗
6. A Comprehensive Review on Choice of Hybrid Vehicles and Power Converters, Control Strategies for Hybrid Electric Vehicles10.1002/er.3952 ↗
7. Review of Fault Diagnosis and Fault-Tolerant Control Technologies for Permanent-Magnet Synchronous Machine10.30941/CESTEMS.2025.00022 ↗
8. An Innovative Semi-FEA Based, Variable Magnet-Step-Skew to Minimize Cogging Torque and Torque Pulsations in Permanent Magnet Synchronous Motors10.1109/ACCESS.2020.3038340 ↗
9. Modal Analysis and Structure Optimization of Permanent Magnet Synchronous Motor10.1109/ACCESS.2020.3017679 ↗
10. Radial Force Characteristics of a Consequent-Pole Permanent Magnet Synchronous Motor10.1109/TIA.2023.3302840 ↗
11. Design and Analysis of a New Inverted-T Shape Permanent Magnet Servo Motor With Irregular Flux Barriers for Low Torque Ripple10.1109/TIE.2025.3544205 ↗
12. Development and Analysis of Dual Three-Phase PMSM With Phase-Shifted Hybrid Winding for Aircraft Electric Propulsion Application10.1109/TTE.2023.3334026 ↗
13. High-speed, high-power motor design for a four-legged robot actuator optimized using the weighted sum and response surface methods10.30941/CESTEMS.2021.00026 ↗
14. Comparative Study of Interior Permanent Magnet, Induction, and Switched Reluctance Motor Drives for EV and HEV Applications10.1109/TTE.2015.2470092 ↗
15. Krichi, M., Noman, A.M., Fannakh, M., Raffak, T., and Haidar, Z.A. (2025). Sustainable Electric Micromobility Through Integrated Power Electronic Systems and Control Strategies. Energies, 18.10.3390/en18082143 ↗
16. Analysis of Lightweight Dual-Rotor Yokeless-Stator PMSM for Electrified Aircraft Propulsion Considering Thermal Benefits of Heat Pipes10.1109/TTE.2025.3570242 ↗
17. Ibrahim, M., Järg, O., Seppago, R., and Rassõlkin, A. (2025). Performance Optimization of a High-Speed Permanent Magnet Synchronous Motor Drive System for Formula Electric Vehicle Application. Sensors, 25.10.3390/s25103156 ↗
18. Cogging Torque Reduction in Permanent Magnet Machines10.1109/TIA.2007.908160 ↗
19. Loss calculation and thermal analysis for high-speed permanent magnet synchronous machines
20. Torque Ripple Suppression for High-Speed Slotless PMSM Considering Unbalanced Back-EMF and Dead-Time Effect10.1109/ACCESS.2026.3669781 ↗
21. Torque Ripple Minimization of PMSM Based on Robust ILC Via Adaptive Sliding Mode Control10.1109/TPEL.2017.2711098 ↗
22. Chu, C., and Huang, Y. (2022). Analysis and Verification of the Method of Improving Inductance by Magnetic Endcaps in Slotless Permanent Magnet Motor. Machines, 10.10.3390/machines10040274 ↗
23. Design of a Slotless Structure for Minimizing Cogging Torque and Torque Ripple in a Column Type EPS Motor for Vehicles
24. Slotless lightweight motor for aerial applications10.1109/TIA.2019.2935055 ↗
25. High-performance current regulation and efficient PWM implementation for low-inductance servo motors10.1109/28.793364 ↗
26. Current-ripple prediction for three-phase PWM converters10.1109/TIA.2013.2270224 ↗
27. Zhang, Y., Lawhorn, D., Han, P., Cramer, A.M., and Ionel, D.M. (2020). Electric Drives with Wide Bandgap Devices for Two-Phase Very Low Inductance Machines. Proceedings of the 2020 IEEE Energy Conversion Congress and Exposition (ECCE), Detroit, MI, USA, 11–15 October 2020, IEEE.10.1109/ECCE44975.2020.9235388 ↗
28. Leandro, M., Bianchi, N., Molinas, M., and Ummaneni, R.B. (2019). Low Inductance Effects on Electric Drives using Slotless Permanent Magnet Motors: A Framework for Performance Analysis. Proceeding of the 2019 IEEE International Electric Machines & Drives Conference (IEMDC), San Diego, CA, USA, 12–15 May 2019, IEEE.10.1109/IEMDC.2019.8785241 ↗
29. Hsu, C., Yang, S., and Chen, J. (2019). Implementation of Low Inductance Permanent Magnet Machine Drive with LC Filter for Field Oriented Control. Proceedings of the 2019 IEEE Energy Conversion Congress and Exposition (ECCE), Baltimore, MD, USA, 29 September–3 October 2019, IEEE.10.1109/ECCE.2019.8913165 ↗
30. Generalized closed-loop control schemes with embedded virtual impedances for voltage source converters with LC or LCL filters10.1109/TPEL.2011.2168427 ↗
31. Field Weakening Operation of Slotless Permanent Magnet Machines Using Stator Embedded Inductor10.1109/TIA.2021.3061043 ↗
32. Su, G.J., and Adams, D.J. (2001). Multilevel DC link inverter for brushless permanent magnet motors with very low inductance. Proceedings of the Conference Record of the 2001 IEEE Industry Applications Conference. 36th IAS Annual Meeting (Cat. No.01CH37248), Chicago, IL, USA, 30 September–4 October 2001, IEEE.
33. An ultrahigh-speed, low power electrical drive system10.1109/TIE.2007.911950 ↗
34. Low inductance axial flux BLDC motor drive for more electric aircraft10.1049/iet-pel.2010.0329 ↗
35. Performance evaluation of high-power SiC MOSFET modules in comparison to Si IGBT modules10.1109/TPEL.2018.2834345 ↗
36. Morya, A., Moosavi, M., Gardner, M., and Toliyat, H. (2017). Applications of Wide Bandgap (WBG) devices in AC electric drives: A technology status review. Proceedings of the 2017 IEEE International Electric Machines and Drives Conference (IEMDC), Miami, FL, USA, 21–24 May 2017, IEEE.10.1109/IEMDC.2017.8002288 ↗
37. Wide Bandgap Devices in AC Electric Drives: Opportunities and Challenges10.1109/TTE.2019.2892807 ↗
38. Chulaee, A., Mohammadi, A., Cramer, A., and Ionel, D.M. (2023). Flexible Control for Wide Speed Range Operation of High Polarity Stator Coreless AFPM Machines with WBG Semiconductor Devices. Proceedings of the 2023 IEEE Energy Conversion Congress and Exposition (ECCE), Nashville, TN, USA, 29 October–2 November 2023, IEEE.10.1109/ECCE53617.2023.10362842 ↗
39. Design and Analysis of a GaN-Based Megahertz Integrated Motor Drive for a PCB Motor10.1109/TIE.2024.3390736 ↗
40. Review of Research on Axial Flux Printed Circuit Board Motor Development10.1109/TTE.2026.3670162 ↗