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Toward understanding the microstructure characteristics,phase selection and magnetic properties of laser additive manufactured Nd-Fe-B permanent magnets 被引量:1
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作者 Bo Yao Nan Kang +6 位作者 Xiangyu Li Dou Li Mohamed EL Mansori Jing Chen Haiou Yang Hua Tan Xin Lin 《International Journal of Extreme Manufacturing》 SCIE EI CAS CSCD 2024年第1期277-294,共18页
Nd-Fe-B permanent magnets play a crucial role in energy conversion and electronic devices.The essential magnetic properties of Nd-Fe-B magnets,particularly coercivity and remanent magnetization,are significantly infue... Nd-Fe-B permanent magnets play a crucial role in energy conversion and electronic devices.The essential magnetic properties of Nd-Fe-B magnets,particularly coercivity and remanent magnetization,are significantly infuenced by the phase characteristics and microstructure.In this work,Nd-Fe-B magnets were manufactured using vacuum induction melting(VIM),laser directed energy deposition(LDED)and laser powder bed fusion(LPBF)technologies.Themicrostructure evolution and phase selection of Nd-Fe-B magnets were then clarified in detail.The results indicated that the solidification velocity(V)and cooling rate(R)are key factors in the phase selection.In terms of the VIM-casting Nd-Fe-B magnet,a large volume fraction of theα-Fe soft magnetic phase(39.7 vol.%)and Nd2Fe17Bxmetastable phase(34.7 vol.%)areformed due to the low R(2.3×10-1?C s-1),whereas only a minor fraction of the Nd2Fe14B hard magnetic phase(5.15 vol.%)is presented.For the LDED-processed Nd-Fe-B deposit,although the Nd2Fe14B hard magnetic phase also had a low value(3.4 vol.%)as the values of V(<10-2m s-1)and R(5.06×103?C s-1)increased,part of theα-Fe soft magnetic phase(31.7vol.%)is suppressed,and a higher volume of Nd2Fe17Bxmetastable phases(47.5 vol.%)areformed.As a result,both the VIM-casting and LDED-processed Nd-Fe-B deposits exhibited poor magnetic properties.In contrast,employing the high values of V(>10-2m s-1)and R(1.45×106?C s-1)in the LPBF process resulted in the substantial formation of the Nd2Fe14B hard magnetic phase(55.8 vol.%)directly from the liquid,while theα-Fe soft magnetic phase and Nd2Fe17Bxmetastable phase precipitation are suppressed in the LPBF-processed Nd-Fe-B magnet.Additionally,crystallographic texture analysis reveals that the LPBF-processedNd-Fe-B magnets exhibit isotropic magnetic characteristics.Consequently,the LPBF-processed Nd-Fe-B deposit,exhibiting a coercivity of 656 k A m-1,remanence of 0.79 T and maximum energy product of 71.5 k J m-3,achieved an acceptable magnetic performance,comparable to other additive manufacturing processed Nd-Fe-B magnets from MQP(Nd-lean)Nd-Fe-Bpowder. 展开更多
关键词 laser additive manufacturing(LAM) Nd-Fe-B permanent magnets numerical simulation microstructure magnetic properties
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Disturbances rejection optimization based on improved two-degree-of-freedom LADRC for permanent magnet synchronous motor systems 被引量:1
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作者 Chenggang Wang Jianhu Yan +2 位作者 Wenlong Li Liang Shan Le Sun 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第3期518-531,共14页
Permanent magnet synchronous motor(PMSM)speed control systems with conventional linear active disturbance rejection control(CLADRC)strategy encounter issues regarding the coupling between dynamic response and disturba... Permanent magnet synchronous motor(PMSM)speed control systems with conventional linear active disturbance rejection control(CLADRC)strategy encounter issues regarding the coupling between dynamic response and disturbance suppression and have poor performance in suppressing complex nonlinear disturbances.In order to address these issues,this paper proposes an improved two-degree-of-freedom LADRC(TDOF-LADRC)strategy,which can enhance the disturbance rejection performance of the system while decoupling entirely the system's dynamic and anti-disturbance performance to boost the system robustness and simplify controller parameter tuning.PMSM models that consider total disturbances are developed to design the TDOF-LADRC speed controller accurately.Moreover,to evaluate the control performance of the TDOF-LADRC strategy,its stability is proven,and the influence of each controller parameter on the system control performance is analyzed.Based on it,a comparison is made between the disturbance observation ability and anti-disturbance performance of TDOF-LADRC and CLADRC to prove the superiority of TDOF-LADRC in rejecting disturbances.Finally,experiments are performed on a 750 W PMSM experimental platform,and the results demonstrate that the proposed TDOF-LADRC exhibits the properties of two degrees of freedom and improves the disturbance rejection performance of the PMSM system. 展开更多
关键词 permanent magnet synchronous motor(PMSM) Active disturbance rejection control(ADRC) Disturbance observer Two-degree-of-freedom control ANTI-DISTURBANCE
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Current knowledge for the risk factors of early permanent pacemaker implantation following transcatheter aortic valve replacement and what is next for the primary prevention? 被引量:1
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作者 Gen-Min Lin Wei-Chun Huang Chih-Lu Han 《World Journal of Cardiology》 2024年第2期54-57,共4页
In this editorial,we comprehensively summarized the preoperative risk factors of early permanent pacemaker implantation after transcatheter aortic valve replacement(TAVR)among patients with severe aortic stenosis from... In this editorial,we comprehensively summarized the preoperative risk factors of early permanent pacemaker implantation after transcatheter aortic valve replacement(TAVR)among patients with severe aortic stenosis from several renowned clinical studies and focused on the primary prevention of managing the modifiable factors,e.g.,paroxysmal atrial fibrillation before the TAVR. 展开更多
关键词 permanent pacemaker implantation Transcatheter aortic valve replacement Interventricular conduction delay DIABETES Supraventricular arrhythmia
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Research progress of permanent ferrite magnet materials
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作者 XU Bin CHEN Yu-feng +3 位作者 ZHOU Yu-juan LUO Bi-yun ZHONG Shou-guo LIU Xing-ao 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第6期1723-1762,共40页
Permanent ferrite magnet materials are extensively employed due to their exceptional magnetic properties and cost-effectiveness.The fast development in electromobile and household appliance industries contributes to a... Permanent ferrite magnet materials are extensively employed due to their exceptional magnetic properties and cost-effectiveness.The fast development in electromobile and household appliance industries contributes to a new progress in permanent ferrite materials.This paper reviews the deveolpement and progress of permanent ferrite magnet industry in recent years.The emergence of new raw material,the advancement of perparation methods and manufacturing techniques,and the potential applications of permanent ferrite materials are introduced and discussed.Specifically,nanocrystallization plays a crucial role in achieving high performance at a low cost and reducing reliance on rare earth resources,and therefore it could be a promising development trendency. 展开更多
关键词 permanent ferrite magnetic materials HIGH-PERFORMANCE nanosizing
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Effect of antioxidants on the efficiency of jet milling and the powder characteristics of Sm2Co17 permanent magnets
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作者 Da-Shuai Xu Lei Liu +6 位作者 Jian-Hui Yuan Bo Zhou Chuang-Hui Dong Feng-Qing Wang Yong Ding Ying-Li Sun A-Ru Yan 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第9期615-620,共6页
This study investigated the effect of antioxidants on the grinding efficiency,magnetic powder characteristics,microstructure,and magnetic properties of 2:17 type SmCo permanent magnet materials.The results show that a... This study investigated the effect of antioxidants on the grinding efficiency,magnetic powder characteristics,microstructure,and magnetic properties of 2:17 type SmCo permanent magnet materials.The results show that adding antioxidants helps improve the dispersion among magnetic powders,leading to a 33.3%decrease in jet milling time and a 15.8%increase in magnet powder production yield.Additionally,adding antioxidants enhances the oxidation resistance of the magnetic powders.After being stored in a constant temperature air environment at 25C for 48 h,the O content in the powder decreased by 33%compared to samples without antioxidants.While in the magnet body,the O content decreased from 0.21 wt.%to 0.14 wt.%,which helps increase the effective Sm content and domain wall pinning uniformity in the magnet.Excellent magnetic properties were obtained in the magnet with added antioxidants:B_(r)=11.6 kGs,SF=79.6%,H_(cj)=16.8 kOe,and(BH)_(max)=32.5 MGOe. 展开更多
关键词 ANTIOXIDANT SmCo permanent magnet oxidation resistance grinding efficiency
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Parental Knowledge of Pre-Hospital Management of Avulsed Permanent Tooth in Children at Kath
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作者 Ama Agyeibea Amuasi Samuel K. Addo Solomon Obiri-Yeboah 《Open Journal of Stomatology》 2024年第2期87-102,共16页
BACKGROUND: Permanent tooth avulsion is one of the severe forms of dental traumatic injuries. The immediate action taken at the site of the accident is crucial to the prognosis of the tooth. Replantation is considered... BACKGROUND: Permanent tooth avulsion is one of the severe forms of dental traumatic injuries. The immediate action taken at the site of the accident is crucial to the prognosis of the tooth. Replantation is considered as the treatment of choice. OBJECTIVE: The study was undertaken to assess the knowledge of parents who accompany their children to the pediatric dental clinic, KATH on the pre-hospital management of avulsed permanent tooth in children. METHODS: A researcher administered structured questionnaire was used to collect data on the knowledge of pre-hospital management of avulsed permanent tooth from 83 parents who accompanied their wards to the pediatric dental clinic at KATH. RESULTS: A total of 83 parents were involved in the study. 30 (36%) were males while 53 (64%) were females. The majority of the parents (57%) were either university trained or had attended college of education. Only 32 parents (39%) were aware of the possibility of replantation. Majority of the parents chose non-physiologic media as the transport media of choice and only 10% would attempt self-replantation before seeking professional help. 76 parents (92%) had no previous education on pre-hospital management of avulsed tooth. CONCLUSION: The results obtained from this study indicate that parental knowledge on pre-hospital management of avulsed permanent tooth is low hence the need for massive public educational campaigns. 展开更多
关键词 Parental Knowledge Tooth Avulsion Pre-Hospital Management permanent Tooth
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Improved Particle Swarm Optimization for Parameter Identification of Permanent Magnet Synchronous Motor
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作者 Shuai Zhou Dazhi Wang +2 位作者 Yongliang Ni Keling Song Yanming Li 《Computers, Materials & Continua》 SCIE EI 2024年第5期2187-2207,共21页
In the process of identifying parameters for a permanent magnet synchronous motor,the particle swarm optimization method is prone to being stuck in local optima in the later stages of iteration,resulting in low parame... In the process of identifying parameters for a permanent magnet synchronous motor,the particle swarm optimization method is prone to being stuck in local optima in the later stages of iteration,resulting in low parameter accuracy.This work proposes a fuzzy particle swarm optimization approach based on the transformation function and the filled function.This approach addresses the topic of particle swarmoptimization in parameter identification from two perspectives.Firstly,the algorithm uses a transformation function to change the form of the fitness function without changing the position of the extreme point of the fitness function,making the extreme point of the fitness function more prominent and improving the algorithm’s search ability while reducing the algorithm’s computational burden.Secondly,on the basis of themulti-loop fuzzy control systembased onmultiplemembership functions,it is merged with the filled function to improve the algorithm’s capacity to skip out of the local optimal solution.This approach can be used to identify the parameters of permanent magnet synchronous motors by sampling only the stator current,voltage,and speed data.The simulation results show that the method can effectively identify the electrical parameters of a permanent magnet synchronous motor,and it has superior global convergence performance and robustness. 展开更多
关键词 Transformation function filled function fuzzy particle swarm optimization algorithm permanent magnet synchronous motor parameter identification
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Risk of permanent pacemaker implantation following transcatheter aortic valve replacement:Which factors are most relevant?
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作者 Akash Batta Juniali Hatwal 《World Journal of Cardiology》 2024年第2期49-53,共5页
Transcatheter aortic valve replacement(TAVR)has emerged as a formidable treatment option for severe symptomatic aortic stenosis ahead of surgical aortic valve replacement.The encouraging results from large randomized ... Transcatheter aortic valve replacement(TAVR)has emerged as a formidable treatment option for severe symptomatic aortic stenosis ahead of surgical aortic valve replacement.The encouraging results from large randomized controlled trials has resulted in an exponential rise in the use of TAVR even in the low-risk patients.However,this is not without challenges.Need for permanent pacemaker(PPM)post-TAVR remains the most frequent and clinically relevant challenge.Naturally,identifying risk factors which predispose an individual to develop high grade conduction block post-TAVR is important.Various demographic factors,electrocardiographic features,anatomic factors and procedural characteristics have all been linked to the development of advanced conduction block and need for PPM following TAVR.Amongst these electrophysiological variables,most notably a prolonged QRS>120 ms regardless of the type of conduction block seems to be one of the strongest predictors on logistic regression models.The index study by Nwaedozie et al highlights that patients requiring PPM post-TAVR had higher odds of having a baseline QRS>120 ms and were more likely to be having diabetes mellitus that those who did not require PPM. 展开更多
关键词 Transcatheter aortic valve replacement permanent pacemaker Diabetes mellitus QRS duration Electrophysiological variables
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Review of Field Weakening Control Strategies of Permanent Magnet Synchronous Motors
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作者 Runze Jing Gaolin Wang +1 位作者 Guoqiang Zhang Dianguo Xu 《CES Transactions on Electrical Machines and Systems》 EI CSCD 2024年第3期319-331,共13页
Due to high power density,high efficiency,and accurate control performance,permanent magnet synchronous motors(PMSMs)have been widely adopted in equipment manufacturing and energy transformation fields.To expand the s... Due to high power density,high efficiency,and accurate control performance,permanent magnet synchronous motors(PMSMs)have been widely adopted in equipment manufacturing and energy transformation fields.To expand the speed range under finite DC-bus voltage,extensive research on field weakening(FW)control strategies has been conducted.This paper summarizes the major FW control strategies of PMSMs,which are categorized into calculation-based methods,voltage closed-loop control methods,and model predictive control related methods.The existing strategies are analyzed and compared according to performance,robustness,and execution difficulty,which can facilitate the implementation of FW control. 展开更多
关键词 Calculation-based methods Field weakening control Model predictive control permanent magnet synchronous motor OVERMODULATION Voltage closed-loop control
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Effect of Brisk Walking on Self-Care Agency or Care Dependency among Colorectal Cancer Patients with Permanent Stoma
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作者 Zhen Zhang Anabella G.Javier 《Journal of Clinical and Nursing Research》 2024年第5期68-82,共15页
Objective:The purpose of this study was to determine the effectiveness of brisk walking as an intervention for self-care agency and care dependency in patients with permanent colorectal cancer stoma.Method:This study ... Objective:The purpose of this study was to determine the effectiveness of brisk walking as an intervention for self-care agency and care dependency in patients with permanent colorectal cancer stoma.Method:This study adopted a quasi-experimental research design,specifically a non-equivalent control group pre-test and post-test design.Utilizing the Exercise of Self-Care Agency Scale(ESCA)and Care Dependency Scale(CDS),a survey was administered to 64 patients from a hospital in Shandong Province.The statistical methods used for analyzing data included frequency,mean,standard deviation(SD),independent t-test,P-value calculation,and dependent t-test.Result:After two months of a brisk walking exercise program,participants in the experimental group had a higher level of self-care agency than before the experiment(P<0.05),and their level of care dependency was significantly reduced(P<0.05).Participants in the control group also showed higher levels of self-care agency(P<0.05)and lower levels of care dependency(P<0.05)after two months compared to their levels before the two months.Conclusion:The brisk walking program had a positive impact on patients’self-care agency and reduced their care dependency. 展开更多
关键词 permanent stoma Colorectal cancer Brisk walking Self-care agency Care dependency
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Analysis of electromagnetic characteristics of typical faults in permanent magnet wind generators 被引量:2
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作者 Guangwei Liu Wenbin Yu +2 位作者 Xiaodong Wang Yun Teng Zhe Chen 《Global Energy Interconnection》 EI CAS CSCD 2023年第1期103-114,共12页
Due to the harsh actual operating environment of the permanent magnet wind turbine,it is easy to break down and difficult to monitor.Therefore,the electromagnetic characteristics identification of major fault types of... Due to the harsh actual operating environment of the permanent magnet wind turbine,it is easy to break down and difficult to monitor.Therefore,the electromagnetic characteristics identification of major fault types of large-scale permanent magnet wind turbines is studied in this paper.The typical faults of rotor eccentricity,stator winding short circuit and permanent magnet demagnetization of permanent magnet wind turbines are analyzed theoretically.The wavelet analysis algorithm is used to decompose and reconstruct the abnormal electromagnetic signal waveform band,and the characteristic frequency of the electromagnetic signal is obtained when the fault occurs.In order to verify the effectiveness of the proposed method,a 3.680MW permanent magnet wind turbine was taken as the research object.Its physical simulation model was established,and an external circuit was built to carry out field co-simulation.The results show that the motor fault type can be determined by detecting the change rule of fault characteristic frequency in the spectrum diagram,and the electromagnetic characteristic analysis can be applied to the early monitoring of the permanent magnet wind turbine fault. 展开更多
关键词 Rotor eccentricity Stator winding short circuit permanent magnet demagnetization Wavelet packet
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Micromagnetic study of magnetization reversal in inhomogeneous permanent magnets 被引量:1
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作者 杨质 陈源源 +7 位作者 刘卫强 李玉卿 丛利颖 吴琼 张红国 路清梅 张东涛 岳明 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第4期646-651,共6页
Macroscopic magnetic properties of magnets strongly depend on the magnetization process and the microstructure of the magnets.Complex materials such as hard-soft exchange-coupled magnets or just real technical materia... Macroscopic magnetic properties of magnets strongly depend on the magnetization process and the microstructure of the magnets.Complex materials such as hard-soft exchange-coupled magnets or just real technical materials with impurities and inhomogeneities exhibit complex magnetization behavior.Here we investigate the effects of size,volume fraction,and surroundings of inhomogeneities on the magnetic properties of an inhomogeneous magnetic material via micromagnetic simulations.The underlying magnetization reversal and coercivity mechanisms are revealed.Three different demagnetization characteristics corresponding to the exchange coupling phase,semi-coupled phase,and decoupled phase are found,depending on the size of inhomogeneities.In addition,the increase in the size of inhomogeneities leads to a transition of the coercivity mechanism from nucleation to pinning.This work could be useful for optimizing the magnetic properties of both exchange-coupled nanomagnets and inhomogeneous single-phase magnets. 展开更多
关键词 permanent magnets micromagnetic simulation EXCHANGE-COUPLING MULTILAYERS
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Prediction of permanent pacemaker implantation after transcatheter aortic valve replacement:The role of machine learning 被引量:1
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作者 Pradyumna Agasthi Hasan Ashraf +16 位作者 Sai Harika Pujari Marlene Girardo Andrew Tseng Farouk Mookadam Nithin Venepally Matthew R Buras Bishoy Abraham Banveet K Khetarpal Mohamed Allam Siva K Mulpuru MD Mackram F Eleid Kevin L Greason Nirat Beohar John Sweeney David Fortuin David R Jr Holmes Reza Arsanjani 《World Journal of Cardiology》 2023年第3期95-105,共11页
BACKGROUND Atrioventricular block requiring permanent pacemaker(PPM)implantation is an important complication of transcatheter aortic valve replacement(TAVR).Application of machine learning could potentially be used t... BACKGROUND Atrioventricular block requiring permanent pacemaker(PPM)implantation is an important complication of transcatheter aortic valve replacement(TAVR).Application of machine learning could potentially be used to predict preprocedural risk for PPM.AIM To apply machine learning to be used to predict pre-procedural risk for PPM.METHODS A retrospective study of 1200 patients who underwent TAVR(January 2014-December 2017)was performed.964 patients without prior PPM were included for a 30-d analysis and 657 patients without PPM requirement through 30 d were included for a 1-year analysis.After the exclusion of variables with near-zero variance or≥50%missing data,167 variables were included in the random forest gradient boosting algorithm(GBM)optimized using 5-fold cross-validations repeated 10 times.The receiver operator curve(ROC)for the GBM model and PPM risk score models were calculated to predict the risk of PPM at 30 d and 1 year.RESULTS Of 964 patients included in the 30-d analysis without prior PPM,19.6%required PPM post-TAVR.The mean age of patients was 80.9±8.7 years.42.1%were female.Of 657 patients included in the 1-year analysis,the mean age of the patients was 80.7±8.2.Of those,42.6%of patients were female and 26.7%required PPM at 1-year post-TAVR.The area under ROC to predict 30-d and 1-year risk of PPM for the GBM model(0.66 and 0.72)was superior to that of the PPM risk score(0.55 and 0.54)with a P value<0.001.CONCLUSION The GBM model has good discrimination and calibration in identifying patients at high risk of PPM post-TAVR. 展开更多
关键词 Transcatheter aortic valve replacement permanent pacemaker implantation Machine learning
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Design and Optimization of Interior Permanent Magnet(IPM)Motor for Electric Vehicle Applications 被引量:2
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作者 Lavanya Balasubramanian Nurul Azim Bhuiyan +3 位作者 Asad Javied Ashraf A.Fahmy Fawzi Belblidia Johann Sienz 《CES Transactions on Electrical Machines and Systems》 CSCD 2023年第2期202-209,共8页
This paper explores some design parameters of an interior permanent magnet synchronous motor that contribute to enhancing motor performance.Various geometry parameters such as magnet dimension,machine diameter,stator ... This paper explores some design parameters of an interior permanent magnet synchronous motor that contribute to enhancing motor performance.Various geometry parameters such as magnet dimension,machine diameter,stator teeth height,and number of poles are analyzed to compare overall torque,power,and torque ripples in order to select the best design parameters and their ranges.Pyleecan,an open-source software,is used to design and optimize the motor for electric vehicle applications.Following optimization with Non-dominated Sorting Genetic Algorithm(NSGA-Ⅱ),two designs A and B were obtained for two objective functions and the corresponding torque ripples values of the design A and B were later reduced by 32%and 77%.Additionally,the impact of different magnet grades on the output performances is analyzed. 展开更多
关键词 Electric vehicles IPM motor Magnet grade OPTIMIZATION permanent magnet motor Torque ripple
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Cascaded Model Predictive Control of Six-phase Permanent Magnet Synchronous Motor with Fault Tolerant Ability 被引量:1
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作者 Ling Feng Zhaohui Wang +1 位作者 Jianghua Feng Wensheng Song 《CES Transactions on Electrical Machines and Systems》 CSCD 2023年第3期311-319,共9页
In the field of high-power electric drives, multiphase motors have the advantages of high power-density, excellent fault tolerance and control flexibility. But their decoupling control and modulation process are much ... In the field of high-power electric drives, multiphase motors have the advantages of high power-density, excellent fault tolerance and control flexibility. But their decoupling control and modulation process are much more complicated compared with three-phase motors due to the increased degree of freedom. Finite control set model predictive control can reduce the difficulties of controlling six-phase motors because it does not require modulation process. In this paper, a cascaded model predictive control strategy is proposed for the optimal control of high-power six-phase permanent magnet synchronous motors. Firstly, the current prediction model of torque and harmonic subspaces are established by decoupling the six-phase spatial variables. Secondly, a cascaded cost function with fault-tolerant capability is proposed to eliminate the weighting factor in the cost function. And finally, the proposed strategy is demonstrated through theoretical analysis and experiments. It is validated that the proposed method is able to maintain excellent steady-state control accuracy and fast dynamic response while significantly reduce the control complexity of the system. Besides, it can easily achieve fault-tolerant operation under open-phase fault. 展开更多
关键词 Fault-tolerant control Model predictive control permanent magnet synchronous motor Six-phase motor Weighting factor
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Speed Regulation Method Using Genetic Algorithm for Dual Three-phase Permanent Magnet Synchronous Motors 被引量:1
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作者 Xiuhong Jiang Yuying Wang Jiarui Dong 《CES Transactions on Electrical Machines and Systems》 CSCD 2023年第2期171-178,共8页
Dual three-phase Permanent Magnet Synchronous Motor(DTP-PMSM)is a nonlinear,strongly coupled,high-order multivariable system.In today’s application scenarios,it is difficult for traditional PI controllers to meet the... Dual three-phase Permanent Magnet Synchronous Motor(DTP-PMSM)is a nonlinear,strongly coupled,high-order multivariable system.In today’s application scenarios,it is difficult for traditional PI controllers to meet the requirements of fast response,high accuracy and good robustness.In order to improve the performance of DTP-PMSM speed regulation system,a control strategy of PI controller based on genetic algorithm is proposed.Firstly,the basic mathematical model of DTP-PMSM is established,and the PI parameters of DTP-PMSM speed regulation system are optimized by genetic algorithm,and the modeling and simulation experiments of DTP-PMSM control system are carried out by MATLAB/SIMULINK.The simulation results show that,compared with the traditional PI control,the proposed algorithm significantly improves the performance of the control system,and the speed output overshoot of the GA-PI speed control system is smaller.The anti-interference ability is stronger,and the torque and double three-phase current output fluctuations are smaller. 展开更多
关键词 Dual three-phase permanent magnet synchronous motor Genetic algorithm PI control Speed regulation
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Design and Performance Analysis of Permanent Magnet Claw Pole Machine with Hybrid Cores 被引量:1
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作者 Chengcheng Liu Zheng Chao +1 位作者 Shaopeng Wang Youhua Wang 《CES Transactions on Electrical Machines and Systems》 CSCD 2023年第3期275-283,共9页
Permanent magnet claw pole machine(PMCPM) is a special kind of transverse flux permanent magnet machine. Compared with other electrical machines, it has the advantages of high torque density and high efficiency for hi... Permanent magnet claw pole machine(PMCPM) is a special kind of transverse flux permanent magnet machine. Compared with other electrical machines, it has the advantages of high torque density and high efficiency for high speed operation. However, because of its complex irregular structure, the manufacturing process using silicon sheets is complicated. Soft magnetic composite material(SMC) is manufactured by powder metallurgy technology, which can produce various shapes of stator core structures, so it is easier to produce various irregular shapes of the stator core. However, the raw SMC material is relatively expensive, and the mechanical strength of SMC is weak. In this paper, a PMCPM with hybrid cores is proposed. With the adoption of hybrid silicon sheet-SMC cores and amorphous alloy-SMC cores, the torque ability of PMCPM can be improved greatly and it can have higher efficiency for more wide operation frequency. Meanwhile, its mechanical strength has been improved and it can be designed for high torque direct drive applications as it is a modular machine. Furthermore, three methods are proposed to reduce the additional eddy current loss which resulted from the employment of hybrid cores in PMCPM. 展开更多
关键词 permanent magnet claw pole machine(PMCPM) Soft magnetic materials(SMC) Hybrid cores Eddy current loss
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Adaptive Gain Tuning Rule for Nonlinear Sliding-mode Speed Control of Encoderless Three-phase Permanent Magnet Assisted Synchronous Motor 被引量:1
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作者 Ghada A.Abdel Aziz Rehan Ali Khan 《CES Transactions on Electrical Machines and Systems》 CSCD 2023年第3期301-310,共10页
In this paper, an adaptive gain tuning rule is designed for the nonlinear sliding mode speed control(NSMSC) in order to enhance the dynamic performance and the robustness of the permanent magnet assisted synchronous r... In this paper, an adaptive gain tuning rule is designed for the nonlinear sliding mode speed control(NSMSC) in order to enhance the dynamic performance and the robustness of the permanent magnet assisted synchronous reluctance motor(PMa-Syn RM) with considering the parameter uncertainties. A nonlinear sliding surface whose parameters are altering with time is designed at first. The proposed NSMSC can minimize the settling time without any overshoot via utilizing a low damping ratio at starting along with a high damping ratio as the output approaches the target set-point. In addition, it eliminates the problem of the singularity with the upper bound of an uncertain term that is hard to be measured practically as well as ensures a rapid convergence in finite time, through employing a simple adaptation law. Moreover, for enhancing the system efficiency throughout the constant torque region, the control system utilizes the maximum torque per ampere technique. The nonlinear sliding surface stability is assured via employing Lyapunov stability theory. Furthermore, a simple sliding mode estimator is employed for estimating the system uncertainties. The stability analysis and the experimental results indicate the effectiveness along with feasibility of the proposed speed estimation and the NSMSC approach for a 1.1-k W PMa-Syn RM under different speed references, electrical and mechanical parameters disparities, and load disturbance conditions. 展开更多
关键词 permanent magnet assisted synchronous reluctance motor Nonlinear sliding mode speed control Speed estimation Parameter uncertainties Sliding mode estimator
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A Flux Ratio Independent of the Permanent Charge in PNP Models
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作者 Guojian Lin 《Journal of Applied Mathematics and Physics》 2023年第1期1-12,共12页
PNP models with an arbitrary number of positively charged ion species and one negatively charged ion species are studied in this paper under the assumption that positively charged ion species have the same valence and... PNP models with an arbitrary number of positively charged ion species and one negatively charged ion species are studied in this paper under the assumption that positively charged ion species have the same valence and the permanent charge is a piecewise constant function. The permanent charge plays the key role in many functions of an ion channel, such as selectivity and gating. In this paper, using the geometric singular perturbation theory, a flux ratio independent of the permanent charge is proved. 展开更多
关键词 PNP Model The permanent Charge Ionic Flow
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Subclavian Arterial Bleeding during Permanent Pacemaker Implantation: Clinical Case Report and Literature Review
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作者 Si Dung Chu Giang Song Tran +1 位作者 Minh Thi Tran Thu Kim Thi Tran 《Open Journal of Emergency Medicine》 2023年第4期180-185,共6页
Research objective: To study a clinical case that had a complication of subclavian artery bleeding during permanent pacemaker implantation process. Subject and Method: Clinical case report and literature review. Study... Research objective: To study a clinical case that had a complication of subclavian artery bleeding during permanent pacemaker implantation process. Subject and Method: Clinical case report and literature review. Study of a patient had an indication for permanent pacemaker implantation who had complication of subclavian artery bleeding during the procedure. Result: An 84-year-old female patient was admitted to the hospital because of fainting spells with chest pain, on the background of dangerous complex arrhythmias and ischemic heart disease, and was prescribed a pacemaker for this patient. The patient had complication occurred during the procedure, which left subclavian artery bleeding was detected and treated promptly, a cardiac pacemaker was implanted on the right side of the chest, and the patient had a successful endovascular stent cover in the left subclavian artery. Conclude: Subclavian artery bleeding is a rare complication in the procedure of permanent pacemaker implantation, but it can still occur and requires quick detection and timely treatment, needs to be successful in cardiac pacemaker placement and subclavian artery drug-eluting stent cover placement intervention. Individualized patient risk assessment is needed;appropriate and standardized intervention techniques and experience can reduce the occurrence of this variable. 展开更多
关键词 COMPLICATION Subclavian Artery Bleeding permanent Pacemaker Implantation
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