CES Transactions on Electrical Machines and Systems最新文献

{"title":"Self-Air-Cooling Design and Optimization for an Outer-Rotor PMSG in External Still Air","authors":"Sirui Wang;Fangrui Wei;Yong Li;Jianhui Hu;Qian Wang;Pengcheng Ma","doi":"10.30941/CESTEMS.2026.00006","DOIUrl":"https://doi.org/10.30941/CESTEMS.2026.00006","url":null,"abstract":"For hybrid-electric unmanned aerial vehicles (UAVs), the stable power supply from the onboard permanent magnet synchronous generator (PMSG) is critical. Overheating in the confined compartment can directly lead to power interruption and system failure. Therefore, proactively improving the thermal management is not only a key technical prerequisite for ensuring flight reliability and mission success, but also enhances the machine's efficiency and the overall power density of the system. Targeting the stringent spatial constraints in UAV applications, novel self-air-cooling heat dissipation topologies are investigated and highlighted on the rotor sidewall for compact outer-rotor generators. A systematic optimization framework, centered on a multi-objective genetic algorithm, is developed to Pareto-optimize the fin geometries, balancing thermal performance against aerodynamic penalty. The proposed topologies are innovatively deployed on the rotor sidewall, uniquely combining the structural space of an outer-rotor machine with self-air-cooling to generate directed airflow of varying patterns that directly enhance the cooling efficiency of the stator. The parameters of the designed self-air-cooled heat dissipation topologies are optimized via a multi-objective genetic algorithm. A temperature rise test under windless conditions shows that the proposed self-air-cooled structure reduces the stator temperature of the generator by 37.1 °C at 5000 r/min, confirming the effectiveness and engineering feasibility for practical applications.","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":"10 1","pages":"55-63"},"PeriodicalIF":0.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11470988","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147584937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dual-Axis Versus Single-Axis Excited Constant and Variable Speed Electric Generator and Synchronous Condenser Systems: A Review with Perspective","authors":"Ion Boldea;Adrian Daniel Martin;Lucian Tutelea","doi":"10.30941/CESTEMS.2026.00010","DOIUrl":"https://doi.org/10.30941/CESTEMS.2026.00010","url":null,"abstract":"Modern/distributed electric energy systems, with ever larger penetration of renewable (photovoltaic, wind, wave, and hydro) energy sources and time-variable outputs, are in need of stronger/higher frequency and alternating current (AC) (direct current (DC)) voltage control. In fact, faster and more stable active and reactive power in the presence of frequency and voltage sags and swells is needed. Power electronics-controlled variable speed generators do not have enough energy storage (inertia) for the scope (static synchronous compensators (STATCOMs) included). This is because power electronics tends to decouple the generator from the power system. While virtual inertia control in doubly fed induction generators (DFIGs) offers a partial solution to these problems, a more robust and comprehensive framework is required for advanced grid support. This is how, by extending the dual-excitation principles, the dual-axis excited electric synchronous generators (DE-SG) provide superior flexibility in two variants summarized here: as a multifunctional DFIG and dual-axis vs. single-axis excited synchronous generator (SG), and as a synchronous condenser (SC), with dual DC and AC excitation (as a no-load DFIG with inertia wheel), where variable speed is used to accelerate/ decelerate the SC and thus provide additional assistance in frequency stabilization. These solutions, good for short-time transients, are not meant, however, to replace the large bidirectional energy storage systems (pump-hydro, hydrogen, batteries, etc.) which are crucial for the daily inherent variations of output energy in modern power systems with multiple power sources. The present paper offers a summary of techniques used in the dual-axis excited vs. single-axis excited SGs (SE-SGs), and SCs topologies, modeling, and control for better stability in modern multiple-source energy systems. This survey includes multiple case studies to shed light on prominent methods.","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":"10 1","pages":"1-15"},"PeriodicalIF":0.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11470991","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147584936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on Power Factor Improvement of a PM Vernier In-Wheel Motor with Collaborative Design of PM and Armature Flux Linkage","authors":"Zixuan Xiang;Lei Peng;Xiaoyong Zhu;Jiaqiang Wei;Zhe Yue","doi":"10.30941/CESTEMS.2026.00001","DOIUrl":"https://doi.org/10.30941/CESTEMS.2026.00001","url":null,"abstract":"This paper proposes a collaborative design method for enhancing the power factor and torque of electric motors. First, the intrinsic relationship between flux linkage analysis of the permanent magnet (PM) and armature field and the power factor is explored. Then, the connection between flux linkage and harmonics is established, clarifying the mechanism for improving power factor and torque. Improvements are focused on the PM and permeance. Regarding the PM structure, employing a Y-shaped PM structure effectively increases PM utilization, reduces leakage flux at the outer ends, and enhances the PM flux linkage. Concerning permeance, stator tooth design is optimized to cooperatively improve permeance harmonics, reduce the non-working flux linkage of the armature field, and enhance the fundamental modulation wave of the armature field responsible for torque generation. This improves the power factor while maintaining motor torque. Finally, through PM structural design, the motor torque performance is optimized. Furthermore, the performance of the Y-shaped PM motor is evaluated. A prototype was manufactured and tested. Theoretical analysis and experimental results demonstrate the effectiveness of the proposed method to a significant extent.","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":"10 1","pages":"44-54"},"PeriodicalIF":0.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11424274","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147584938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High Precision Sensorless Control of Rotor Mechanical Position Based on Cross Correction of Dual Air Gap Information","authors":"Yukun Lin;Ronggang Ni;Shengming Yang;Qingwen Deng","doi":"10.30941/CESTEMS.2025.00032","DOIUrl":"https://doi.org/10.30941/CESTEMS.2025.00032","url":null,"abstract":"Position sensors are indispensable in robotic joint servo systems for acquiring mechanical positions, yet their installation inevitably occupies an axial space and increases system complexity, limiting their applicability in compact robot design where spatial constraints and integration efficiency are critical. Sensorless control reduces mechanical and circuit complexity through hardware simplification, but inherently estimates only the electrical instead of mechanical rotor position information, thus remaining constrained in robot joint control applications. Based on the previously proposed dual-gap dual-pole composite machine (DDCM), this paper systematically analyzes the causes of mechanical position estimation errors and proposes a correction method that utilizes a correction coefficient to reduce these errors and enhance estimation accuracy. Furthermore, this paper derives the applicability constraints of the proposed scheme, demonstrating that its requirements for electrical angle position errors are not stringent, thus enabling wide applicability in conventional sensorless control scenarios. The effectiveness of the proposed method is verified by conducting experiments on a 0.75 kW prototype.","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":"9 4","pages":"445-453"},"PeriodicalIF":0.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11322825","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High Frequency Position Offset Injection Based PMSM Winding and Magnet Temperature Decoupled Estimation with Wide Speed Range","authors":"Chengtao Shi;Yuting Lu;Kaide Huang;Chunyan Lai;Beichen Ding;Guodong Feng","doi":"10.30941/CESTEMS.2025.00035","DOIUrl":"https://doi.org/10.30941/CESTEMS.2025.00035","url":null,"abstract":"In permanent magnet synchronous machine (PMSM) drives, temperature information is critical to achieve reliable and high-performance control. The popular model-based estimation methods are based on extracting temperature dependent terms from the voltages using the machine model. The estimation accuracy under low speed or load can be greatly affected by the model uncertainty and noise due to low signal-to-noise ratio. This paper presents a high frequency (HF) position offset injection-based winding and permanent magnet (PM) temperature decoupled estimation approach for PMSMs to achieve accurate and robust temperature estimation among a wide speed range especially under low-speed conditions. In the proposed approach, a small HF position offset is injected into the machine to construct a decoupled winding and PM temperature estimation model, in which the winding and PM temperatures are independently estimated from HF excitations. The temperature estimation is independent from the fundamental model and parameter variation, and it achieves high signal-to-noise ratio under low-speed conditions. Moreover, the temperature estimation is also not affected by magnetic saturation and inverter distortion, which can improve the accuracy and robustness of temperature estimation. The proposed approach is validated with experiments and comparisons on a laboratory machine under various operating conditions.","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":"9 4","pages":"473-482"},"PeriodicalIF":0.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11322769","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Online Simultaneous Identification of Multi-Parameters for Interior PMSMs Under Sensorless Control","authors":"Peng Wang;Z. Q. Zhu;N. M. A. Freire;Ziad Azar;Ximeng Wu;Dawei Liang","doi":"10.30941/CESTEMS.2025.00029","DOIUrl":"https://doi.org/10.30941/CESTEMS.2025.00029","url":null,"abstract":"Under sensorless control, the position estimation error in interior permanent magnet (PM) synchronous machines will lead to parameter identification errors and a rank-deficiency issue. This paper proposes a parameter identification model that is independent of position error by combining the dq-axis voltage equations. Then, a novel dual signal alternate injection method is proposed to address the rank-deficiency issue, i.e., during one injection period, a zero, positive, and negative d-axis current injection together with a rotor position offset injection, to simultaneously identify the multi-parameters, including stator resistance, dq-axis inductances, and PM flux linkage. The proposed method is verified by experiments at different dq-axis current conditions.","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":"9 4","pages":"422-433"},"PeriodicalIF":0.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11322837","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Three-Dimensional Thermal Network Modeling and Temperature Rise Prediction of Nanocrystalline High-Frequency Transformer","authors":"Baolu Wei;Wenliang Zhao;Haibo Ding;Haisen Zhao","doi":"10.30941/CESTEMS.2025.00038","DOIUrl":"https://doi.org/10.30941/CESTEMS.2025.00038","url":null,"abstract":"The internal hotspot temperature rise prediction in nanocrystalline high-frequency transformers (nanoHFTs) is essential to ensure reliable operation. This paper presents a three-dimensional thermal network (3DTN) model for epoxy resin encapsulated nanoHFTs, which aims to precisely predict the temperature distribution inside the transformer in combination with the finite element method (FEM). A magnetothermal bidirectional coupling 3DTN model is established by analyzing the thermal conduction between the core, windings, and epoxy resin, while also considering the convection and radiation heat transfer mechanisms on the surface of the epoxy resin. The model considers the impact of loss distribution in the core and windings on the temperature field and adopts a simplified 1/2 thermal network model to reduce computational complexity. Furthermore, the results of FEM are compared with experimental results to verify the accuracy of the 3DTN model in predicting the temperature rise of nanoHFT. The results show that the 3DTN model reduces errors by an average of 5.25% over the traditional two-dimensional thermal network (2DTN) model, particularly for temperature distributions in the windings and core. This paper provides a temperature rise prediction method for the thermal design and offers a theoretical basis and engineering guidance for the optimization of their thermal management systems.","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":"9 4","pages":"378-389"},"PeriodicalIF":0.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11322831","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Three-Random SVPWM Strategy Based on Markov Chain for NPC Three-Level Inverter","authors":"Xuefeng Jin;Kunyang Wu;Xin Gu;Guozheng Zhang;Huimin Wang;Wei Chen","doi":"10.30941/CESTEMS.2025.00031","DOIUrl":"https://doi.org/10.30941/CESTEMS.2025.00031","url":null,"abstract":"Permanent magnet synchronous motors (PMSMs), owing to the features of low maintenance costs, great efficiency, and high power density, are extensively utilized in applications such as rail transportation, industrial robots, and new energy electric vehicles. However, the application of space vector pulse width modulation (SVPWM) results in the motor phase current exhibiting clustered harmonic distributions at the integer multiples of the switching frequency, leading to motor noise and vibration issues. To address the issues, this paper proposes a three-random SVPWM (TRPWM) strategy based on a three-state Markov chain, integrating random pulse position, random switching frequency, and random small vector dwell time. By adhering to the principle of voltage-second balance, this strategy spreads the concentrated high-frequency harmonics over a wider frequency range, significantly reducing the magnitude of the concentrated harmonics in the phase current. Comparative experiments with conventional SVPWM, conventional dual-random SVPWM, and conventional three-random SVPWM strategies demonstrate that the proposed approach achieves the expansion of harmonics at integer multiples of the switching frequency in the phase current, effectively suppressing high-frequency vibrations in PMSMs.","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":"9 4","pages":"483-494"},"PeriodicalIF":0.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11322834","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low Vibration Design and Investigation of an Interior Permanent Magnet Motor in the Perspective of the Saliency Ratio","authors":"Hui Qu;Li Quan;Xiaoyong Zhu;Zixuan Xiang;Teng Liu;Jiamin Bai","doi":"10.30941/CESTEMS.2025.00040","DOIUrl":"https://doi.org/10.30941/CESTEMS.2025.00040","url":null,"abstract":"To address the issue of increased electromagnetic vibration in permanent magnet (PM) motors for electric vehicles under flux-weakening speed extension operation, this paper proposes a low-vibration design method for PM motors from the perspective of saliency ratio. First, by establishing a theoretical model for vibration analysis under flux-weakening operation, it reveals the vibration mechanism whereby high-order armature magnetomotive force (ARM-MMF) harmonics under flux-weakening operation leads to enhanced radial electromagnetic force (REF). Second, an in-depth investigation into the intrinsic relationship between saliency ratio and ARM-MMF is conducted. This study proposes a novel methodology to design key ARM-MMF harmonics that induce significant electromagnetic vibration from the perspective of the saliency ratio. An innovative rotor topology featuring elliptical-arc composite flux barriers is developed to implement this approach. Furthermore, and synergistic optimization is performed with the saliency ratio and torque as optimization objectives to balance vibration suppression and torque output performance. Finally, a prototype is manufactured and tested. Both theoretical and experimental analyses validated the effectiveness of the motor and the proposed design method.","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":"9 4","pages":"434-444"},"PeriodicalIF":0.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11322841","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Review of Research Methods for Stator Temperature Monitoring in PMSM","authors":"Songze Zhao;Puqi Ning;Tao Fan;Xiaoshuang Hui;Qibiao Shi","doi":"10.30941/CESTEMS.2025.00037","DOIUrl":"https://doi.org/10.30941/CESTEMS.2025.00037","url":null,"abstract":"High-density permanent magnet synchronous motors (PMSMs) are widely used in electric drive systems. However, they are susceptible to temperature influences under complex operating conditions, and prolonged operation at high temperatures can first damage the stator winding insulation, which in turn will damage the windings themselves and cause faults. Therefore, stator temperature monitoring is of crucial importance. This paper summarizes the existing temperature monitoring technologies for stator windings of permanent magnet motors, compares the advantages and disadvantages of various methods to help researchers understand this technology, and analyzes its opportunities and challenges, followed by an outlook.","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":"9 4","pages":"407-421"},"PeriodicalIF":0.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11322838","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}