{"title":"Online Permanent Magnet Temperature Estimation in Permanent Magnet Machines Using Nonlinear Observer With Enhanced Parameter Estimation to Minimise Risk of Demagnetisation","authors":"Ryan Brody, Michael McIntyre, Brandon Grainger","doi":"10.1049/elp2.70043","DOIUrl":"https://doi.org/10.1049/elp2.70043","url":null,"abstract":"<p>Real-time temperature estimation is critical in the control of traction drives for electric vehicles. Efficient control of conventional and novel PMSM machines requires awareness of permanent magnet (PM) temperature to avoid demagnetisation of the magnetic material. This article proposes an online parameter estimation scheme that utilises a nonlinear RISE observer to indirectly estimate the PM temperature of PMSM machines with fast convergence and high accuracy while requiring no a priori knowledge of motor parameters, no additional sensors, and no modifications to an existing motor design. In this work, nonrare earth materials are considered. This particular non-RE material is more sensitive to demagnetisation than RE material. The system architecture and analysis are presented in this article. The scheme is validated through experiments where FEA results and a rapid control prototyping (RCP) test bed are used to demonstrate proof of concept.</p>","PeriodicalId":13352,"journal":{"name":"Iet Electric Power Applications","volume":"19 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/elp2.70043","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143913986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xuebin Lv, Fuzheng Liu, Mingshun Jiang, Faye Zhang, Lei Jia
{"title":"Power Transformer Fault Diagnosis Method Based on SMOTE and Convolution Soft Threshold Network","authors":"Xuebin Lv, Fuzheng Liu, Mingshun Jiang, Faye Zhang, Lei Jia","doi":"10.1049/elp2.70044","DOIUrl":"https://doi.org/10.1049/elp2.70044","url":null,"abstract":"<p>Power transformers play an important role in the entire power grid. However, the fault diagnosis method based on machine learning suffers from decreased diagnostic performance when faced with redundant information interference and unbalanced data interference. In order to solve the above problems, this paper proposes a power transformer fault diagnosis method based on SMOTE and convolutional threshold neural network. First, a convolutional soft threshold network is proposed, which introduces the soft threshold function into the convolutional network to strengthen the perception of important information and suppress redundant information interference. Then, the SMOTE method is introduced into the proposed method, which can generate minority class samples, making the data set more balanced and alleviating the generalisation performance degradation caused by data imbalance. The proposed method is tested on a real power transformer fault data set, and the experimental findings demonstrate its superiority and efficacy.</p>","PeriodicalId":13352,"journal":{"name":"Iet Electric Power Applications","volume":"19 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/elp2.70044","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143904919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"High-Current Cryogenic DC Solid-State Circuit Breaker for Electric Aircraft","authors":"Zhongying Wang, Jiawen Xi, Xianwu Zeng, Emelie Nilsson, Jean-francois Rouquette, Edwin Calderon, Ravi Kiran Surapaneni, Ludovic Ybanez, Xiaoze Pei","doi":"10.1049/elp2.70041","DOIUrl":"https://doi.org/10.1049/elp2.70041","url":null,"abstract":"<p>Cryogenic and superconducting technologies have great potential to significantly enhance the power density and efficiency of electric propulsion aircraft. However, fault protection in on-board DC power networks presents serious challenges, primarily due to the rapid rise and high magnitude of fault currents resulting from the low impedance of closely coupled networks. Furthermore, designing and selecting power electronic devices capable of operating at cryogenic temperatures introduces additional challenges. This paper presents the design of a 300 V/1700 A DC solid-state circuit breaker (SSCB) operating at cryogenic temperatures. The proposed SSCB consists of multiple parallel-connected silicon metal-oxide-semiconductor field-effect transistors (Si-MOSFETs), snubber capacitors and transient voltage suppression (TVS) diodes. A prototype is built and experimentally tested both at room temperature and in a liquid nitrogen (LN<sub>2</sub>) bath to validate the design. Experimental results show that the SSCB prototype, when immersed in LN<sub>2</sub>, achieves an on-state resistance as low as 68 μΩ at the rated current of 1700 A, delivering a high efficiency of 99.96%. Additionally, the SSCB successfully interrupted fault currents of up to 5360 A in LN<sub>2</sub> of 77 K.</p>","PeriodicalId":13352,"journal":{"name":"Iet Electric Power Applications","volume":"19 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/elp2.70041","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143904883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Belkacem Bekhiti, Bachir Nail, Imad Eddine Tibermacine, Ramzi Salim
{"title":"On Hyper-Stability Theory Based Multivariable Nonlinear Adaptive Control: Experimental Validation on Induction Motors","authors":"Belkacem Bekhiti, Bachir Nail, Imad Eddine Tibermacine, Ramzi Salim","doi":"10.1049/elp2.70035","DOIUrl":"https://doi.org/10.1049/elp2.70035","url":null,"abstract":"<p>This paper presents a novel hyperstability-based adaptive control strategy for induction motors, distinguishing itself from conventional model reference adaptive control (MRAC) approaches by integrating enhanced robustness against parametric uncertainties and external disturbances. Unlike traditional adaptive controllers, the proposed Hyper-stable adaptive controller (H-MRAC) ensures improved transient performance and faster convergence rates, validated through both theoretical analysis and experimental verification. Key innovations include the integration of hyper-stability theory into adaptive control design and a comprehensive evaluation of parameter uncertainties, which significantly improves motor performance in variable conditions. Experimental results demonstrate a 42% reduction in integral squared error (ISE), a 37% improvement in integral absolute error (IAE), a 28.7% improvement in integral time absolute error (ITAE) and a 25% faster convergence compared to standard MRAC. A detailed comparison with passivity-based control strategies shows a 26.5% improvement in steady-state performance and 30% faster transient response. Despite these successes, the paper discusses limitations related to computational complexity, real-time implementation challenges, and the impact of sensor noise on control performance. The potential need for DSPs or FPGA-based solutions is also addressed. Finally, the generalisability of the proposed control method across different motor types and power ratings is considered with future directions for broader validation in diverse industrial scenarios.</p>","PeriodicalId":13352,"journal":{"name":"Iet Electric Power Applications","volume":"19 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/elp2.70035","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143896943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Constrained FCS-MPC-Based Current Controller for Voltage Source Converters: Application to Shunt Active Power Filters","authors":"Shahram Karimi, Hesam Seifinejad, Hassan Moradi, Hossein Bagheri, Siroos Hemmati","doi":"10.1049/elp2.70025","DOIUrl":"https://doi.org/10.1049/elp2.70025","url":null,"abstract":"<p>Due to the discrete nature of switching in voltage source converters (VSCs), the finite control set-model predictive control (FCS) can be a proper choice for using in the control system of VSCs. This paper introduces a constrained FCS-based current controller (CFCS-CC) to control VSC output currents. In the proposed CFCS-CC, the objective function is the same as used in the traditional FCS-based current controller (TFCS-CC) and an additional constraint is considered to reduce the average switching frequency. Because only one objective function is used in the suggested current controller, it does not need tunable parameters or weighting factors. Design simplicity and low computational burden are the main advantages of the suggested approach. Because the reference current of shunt active power filters (SAPFs) contains harmonic components, SAPFs require a high-performance current controller. Therefore, the performance of the suggested CFCS-CC is assessed on a three-phase SAPF. The proposed current controller is implemented on field-programmable gate array (FPGA). The results obtained from FPGA in-the-loop simulations and experimental verification show that the suggested CFCS-CC provides a lower switching frequency while maintaining the overall performance of the TFCS-CC, such as fast dynamic response and low total harmonic distortion.</p>","PeriodicalId":13352,"journal":{"name":"Iet Electric Power Applications","volume":"19 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/elp2.70025","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143892915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Analytical Prediction of Optimal Split Ratio for Maximum Torque Per Copper Loss in AFPM Machines","authors":"Lingyun Shao, Tao Liu, Zhuoran Zhang, Xueyi Yan, Zhongze Wu, Wei Hua","doi":"10.1049/elp2.70027","DOIUrl":"https://doi.org/10.1049/elp2.70027","url":null,"abstract":"<p>The axial flux permanent magnet (AFPM) synchronous machine has advantages of high torque density and high efficiency. In the design process, the ratio of inner to outer diameter, that is, the split ratio, directly affects the electromagnetic performance of the AFPM machine, for example, torque, copper loss and efficiency. Due to the three-dimensional magnetic circuit, a fast prediction of the optimal split ratio can significantly reduce the computation load for machine optimization. This paper proposes an analytical method for quickly predicting the optimal split ratio <i>λ</i><sub><i>opt</i></sub> for the maximum torque per copper loss for the AFPM machine. Different from the existing analytically predicted optimal split ratio <i>λ</i><sub><i>opt</i></sub> for the maximum torque, that is, <i>λ</i><sub><i>opt</i></sub> ≈ 0.58, it is found that the optimal split ratio <i>λ</i><sub><i>opt</i></sub> for the maximum torque per copper loss depends on the stator slot number <i>Q</i>, that is, <i>λ</i><sub><i>opt</i></sub> increases with a larger <i>Q</i>, whilst the rotor pole number 2<i>p</i> has little influence on <i>λ</i><sub><i>opt</i></sub>. The accuracy of the proposed prediction method is verified by finite element analysis, and the absolute error is ≤ 1.1%.</p>","PeriodicalId":13352,"journal":{"name":"Iet Electric Power Applications","volume":"19 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/elp2.70027","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143888854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Litong Zheng, Yuhan Guo, Xin Zhao, Xiuyu Zhang, Hongwei Li
{"title":"Optimal Trajectory-Based Thermal Balance Control Strategy of Wide Input Voltage Dual Resonant Cavity LLC Converter for Vehicle Power Supply","authors":"Litong Zheng, Yuhan Guo, Xin Zhao, Xiuyu Zhang, Hongwei Li","doi":"10.1049/elp2.70036","DOIUrl":"https://doi.org/10.1049/elp2.70036","url":null,"abstract":"<p>DC-DC converters in electric vehicles require a wide input voltage range to address voltage fluctuations in power batteries. Thus, this paper proposes a dual resonant cavity converter to achieve a wide input voltage range. Firstly, three different modes are proposed by reconfiguring modulation schemes. The fundamental wave analysis method is used to derive different voltage gain models under three modes. Under this effect, wide input voltage characteristics are achieved by switching between these modes. Meanwhile, the sliding mode control is used to determine the switching frequency. Compared with the traditional control, the dynamic response speed is significantly improved. Moreover, the optimal trajectory-based thermal balance control strategy is proposed to achieve balanced heat production. Therein, optimal trajectory control is used to determine the switching of resonant cavity and topology modes. Therefore, the safety of the converter can be improved due to thermal balance. At the same time, both the resonant current and output voltage fluctuations during mode switching are significantly reduced. Finally, the correctness and feasibility of the proposed topology and strategy are verified through simulation and experimental results.</p>","PeriodicalId":13352,"journal":{"name":"Iet Electric Power Applications","volume":"19 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/elp2.70036","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143871760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dileep Kumar Kana Padinharu, Guang-Jin Li, Guang-Bo Zhang, Zi-Qiang Zhu, Peng Wang, Richard Clark, Ziad Azar
{"title":"Direct-Drive Vernier Machine With Innovative Stator Design for Enhanced Demagnetisation Withstand Capability","authors":"Dileep Kumar Kana Padinharu, Guang-Jin Li, Guang-Bo Zhang, Zi-Qiang Zhu, Peng Wang, Richard Clark, Ziad Azar","doi":"10.1049/elp2.70032","DOIUrl":"https://doi.org/10.1049/elp2.70032","url":null,"abstract":"<p>This paper proposes a Vernier machine with an improved stator design that adopts open stator slots and permanent magnets installed on both the rotor and stator. Compared to an existing Vernier machine in the literature, referred to as Design 1, the exclusive stator slots for permanent magnets in the proposed machine help mitigate demagnetisation issues by physically isolating the windings and the magnets. Additionally, the open stator slot design facilitates the installation of form-wound coils which is desirable for large generators used in direct-drive wind power applications. Using 2-dimensional finite element analysis, the proposed design is compared with a conventional surface-mounted permanent magnet machine, a conventional Vernier machine and Design 1. The findings indicate that the proposed Vernier machine uses both odd and even harmonics to generate torque, and it can exhibit superior electromagnetic performance, including torque and efficiency, compared to the conventional surface-mounted permanent magnet machine and conventional Vernier machines and demonstrate comparable electromagnetic performance to Design 1. Furthermore, to enhance the torque-to-mass ratio of the proposed Vernier machine, through-slots below the stator magnets are introduced and found to be effective without significantly compromising torque and efficiency. The simulations have been validated by experiments based on a prototype.</p>","PeriodicalId":13352,"journal":{"name":"Iet Electric Power Applications","volume":"19 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/elp2.70032","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143871686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Modelling and Simulation of a Novel Axial Flux Permanent Magnet Hysteresis Motor Comparing Different Disc Structures","authors":"Hashem Yousefi Javid, Aydin Yousefi Javid","doi":"10.1049/elp2.70008","DOIUrl":"https://doi.org/10.1049/elp2.70008","url":null,"abstract":"<p>Conventional radial flux permanent magnet hysteresis motor has the advantages of both permanent magnet and hysteresis motor types in starting and steady states. Compared to radial flux, the structure of axial flux motor has many advantages such as high efficiency and torque in similar dimensions, adjustable air-gap and the ability to multi-stack. In this paper, a new structure of axial flux permanent magnet hysteresis motor is presented. To achieve this structure, first, different proposed structures on a disc of axial flux hysteresis motor were analysed by using the elliptical model in finite element software. The motor that has the highest torque in the similar dimensions as well as a simple structure is selected. Next, the equations of the proposed motor are presented. Then, considering the importance of the hysteresis modelling method, using the precise method of the Preisach model, finite element analysis for starting and steady states is made and the results are compared. The results show a considerable increase in the steady state torque compared to the torque of the initial hysteresis motor as well as a favourable starting torque.</p>","PeriodicalId":13352,"journal":{"name":"Iet Electric Power Applications","volume":"19 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/elp2.70008","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Fast Calculation Method of 3D Temperature Field of Oil-Immersed Transformer Based on Point Cloud U-Net++ Neural Network","authors":"Rongyun Fu, Yunpeng Liu, Kexin Liu, Gang Liu, Liwei Jiang, Haoyu Liu, Shuguo Gao","doi":"10.1049/elp2.70026","DOIUrl":"https://doi.org/10.1049/elp2.70026","url":null,"abstract":"<p>To address the challenges in real-time 3D temperature field analysis for intelligent power systems, we propose a fast calculation method based on point cloud U-net++ neural network. Taking a 35 kV oil-immersed transformer as an example, initially, we input key temperature-influencing factors into our algorithm. These input features are randomly combined in a limited range according to a specific step. The sets of 3D temperature are computed by Fluent on the Jinan Shanhe supercomputing platform. And the three-dimensional mathematical model is then converted into point clouds. Finally, we determined the optimal hyperparameters and proceeded with parameter training, evaluation and debugging. The results demonstrate that the method proposed can reduce single calculation time to 0.04 s with the vast majority of the error in the region of 0K or so, significantly improving the efficiency of the calculation. Meanwhile, the U-net++ neural network also achieves significantly higher accuracy than the U-net network. To validate the algorithm's effectiveness, we establish a platform for assessing the temperature increase. The experimental results indicate that the temperature rise trend from U-net++ neural network calculations aligns closely with the experimental data, and the temperature difference is within only 4K.</p>","PeriodicalId":13352,"journal":{"name":"Iet Electric Power Applications","volume":"19 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/elp2.70026","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}