20 results on '"Niu, Shuangxia"'
Search Results
2. Comparative Analysis of Consequent-Pole Flux-Switching Machines with Different Permanent Magnet Arrangements for Outer-Rotor In-Wheel Direct-Drive Applications.
- Author
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Bi, Yanding, Fu, Weinong, Niu, Shuangxia, and Huang, Jiahui
- Subjects
PERMANENT magnets ,AIR gap flux ,FINITE element method ,ELECTROMOTIVE force ,MACHINERY ,ACTINIC flux - Abstract
Recently, the interest in consequent-pole flux-switching permanent magnet (CP-FSPM) machines has been increasing because of the flux-focusing PM arrangements and the removal of the flux-barrier effect. A simple and rigid outer-rotor salient pole rotor structure can be adopted in CP-FSPM machines, making them applicable for in-wheel direct-drive applications. In this study, three CP-FSPM machines with II-shaped (II-PM), V-shaped (V-PM), and straight U-shaped PM (SU-PM) arrays are analyzed and compared. Moreover, a CP-FSPM machine with inclined U-shaped PM (IU-PM) arrays is proposed to improve the flux-focusing effect and stator slot utilization. The working principles of CP-FSPM machines are analyzed by adopting a semi-analytical model. Combining the finite element analysis (FEA) results of air gap flux density and the analytical model of phase back electromotive force (EMF), the contributions of multiple working harmonics to the back EMF are quantitatively analyzed. Additionally, 6/16 and 6/17 CP-FSPM machines with different PM arrangements are globally optimized. Both the no-load and on-load performance of the optimized machines are included in the performance comparison. The results illustrate that the 6/16 and 6/17 machines exhibit their respective merits, and the IU-PM machine shows the best torque production ability in these CP-FSPM machines with the same design criteria. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
3. An Efficient and High-Precision Electromagnetic–Thermal Bidirectional Coupling Reduced-Order Solution Model for Permanent Magnet Synchronous Motors.
- Author
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Yu, Yinquan, Zhao, Pan, Goh, HuiHwang, Carbone, Giuseppe, Niu, Shuangxia, Ding, Junling, Shu, Shengrong, and Zhao, Zhao
- Subjects
REDUCED-order models ,PERMANENT magnet motors ,NUMERICAL calculations ,TEMPERATURE distribution ,TORQUE control ,FINITE fields - Abstract
The traditional electromagnetic–thermal bidirectional coupling model (EMTBCM) of permanent magnet synchronous motors (PMSMs) requires a long time to solve, and the temperature-induced torque change is not accounted for in the finite element (FE) numerical calculation of the EM field. This paper presents a precise and efficient EMTBC reduced-order solution model. The specific methods are as follows: First, a torque control technology based on the current injection method is proposed for determining the effect of temperature on the properties of EM materials and EM torque in an EM field, and the accuracy of the FE numerical calculation model is improved. Second, we use the improved EM field finite element numerical calculation model (FEMNCM) to analyze the correlation between the EM loss, the temperature, and the load, and we replace the FEMNCM with the EM field reduction model using the least-squares method. Then, we analyze the law of the PMSM's internal temperature distribution. We choose the GA-BP algorithm with as few samples as possible and a high accuracy and stability to build the regression prediction model of the temperature field. We use this regression prediction model to replace the complex temperature field calculation. After analyzing the EMTBCM solution strategy, the original complex EMTBC numerical calculation model is substituted with iterations of the magnetic field reduction model and the temperature field regression prediction model. The FE numerical calculation is then used to validate the reduced-order model. The proposed model is validated through numerical simulations. The numerical results indicate that the proposed reduced-order EMTBC model in this paper is accurate and computationally efficient. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
4. A Torque-Enhanced Magnetic-Geared Machine with Dual-Series-Winding and Its Design Approach for Electric Vehicle Powertrain.
- Author
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Chen, Yuanxi, Fu, Weinong, Niu, Shuangxia, and Wang, Sigao
- Abstract
Magnetic gear and magnetic-geared machine (MGM) are the potential solutions in electric vehicles (EVs) powertrains for inherent high efficiency and mechanical simplification. However, the torque density issue of the MGM greatly limits its industrial application. To enhance the torque performance of the MGM, a torque-enhanced magnetic-geared machine with dual-series-winding and its design approach are proposed. The key merits of the proposed design are to achieve a high space utilization with a dual-winding design, with no additional control topologies and power converters required. The auxiliary winding is supplemented and integrated with modulation rings. The relative position of the stator and armature winding are designed and rotated compared to the modulation rings with auxiliary winding, to ensure the auxiliary winding shares the excitation with the armature winding. Accordingly, simplifying the external control topologies. With the proposed design, the torque of the MGM can be significantly enhanced with a single three-phase driving. Theoretical analysis, parameters optimization and electromagnetic verification are given, demonstrating that the proposed machine can achieve an efficiency of 93.2%, generate a torque of 107.2 N·m, and reach a torque density of 10.81 N·m/kg. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
5. Novel Mechanical Flux-Weakening Design of a Spoke-Type Permanent Magnet Generator for Stand-Alone Power Supply.
- Author
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Jiang, Mingyuan and Niu, Shuangxia
- Subjects
PERMANENT magnet generators ,POWER resources ,FINITE element method ,VOLTAGE control ,WIND power ,PERMANENT magnets - Abstract
Featured Application: Stand-alone wind power generator. In this paper, a novel mechanical flux-weakening design of a spoke-type permanent magnet generator for a stand-alone power supply is proposed. By controlling the position of the adjustable modulator ring mechanically, the total induced voltage, i.e., the amplitude of the back EMF vector sum can be effectively adjusted accordingly by the modulation effect. Consequently, the variable-speed constant-amplitude voltage control (VSCAVC) with a large speed range can be achieved. Compared to the electrical flux-weakening method, the mechanical flux-weakening method is easier to operate without the risk of PM demagnetization. The analytical model is presented, and the operation principles are illustrated. To analyze the performance of different combinations of stator/rotor pole pairs, four cases are optimized and analyzed using the finite element method for comparison. The characteristics of VSCAVC are analyzed. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
6. Multi-Objective Optimization Strategy for Permanent Magnet Synchronous Motor Based on Combined Surrogate Model and Optimization Algorithm.
- Author
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Yu, Yinquan, Pan, Yue, Chen, Qiping, Hu, Yiming, Gao, Jian, Zhao, Zhao, Niu, Shuangxia, and Zhou, Shaowei
- Subjects
PERMANENT magnet motors ,MATHEMATICAL optimization ,EVOLUTIONARY algorithms ,LATIN hypercube sampling ,TAGUCHI methods ,FINITE element method - Abstract
When a permanent magnet synchronous motor (PMSM) is designed according to the traditional motor design theory, the performance of the motor is often challenging to achieve the desired goal, and further optimization of the motor design parameters is usually required. However, the motor is a strongly coupled, non-linear, multivariate complex system, and it is a challenge to optimize the motor by traditional optimization methods. It needs to rely on reliable surrogate models and optimization algorithms to improve the performance of the PMSM, which is one of the problematic aspects of motor optimization. Therefore, this paper proposes a strategy based on a combination of a high-precision combined surrogate model and the optimization method to optimize the stator and rotor structures of interior PMSM (IPMSM). First, the variables were classified into two layers with high and low sensitivity based on the comprehensive parameter sensitivity analysis. Then, Latin hypercube sampling (LHS) is used to obtain sample points for highly sensitive variables, and various methods are employed to construct surrogate models for variables. Each optimization target is based on the acquired sample points, from which the most accurate combined surrogate model is selected and combined with non-dominated ranking genetic algorithm-II (NSGA-II) to find the best. After optimizing the high-sensitivity variables, a new finite element model (FEM) is built, and the Taguchi method is used to optimize the low-sensitivity variables. Finally, finite element analysis (FEA) was adopted to compare the performance of the initial model and the optimized ones of the IPMSM. The results showed that the performance of the optimized motor is improved to prove the effectiveness and reliability of the proposed method. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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7. Recent Advances in Multi-Phase Electric Drives Model Predictive Control in Renewable Energy Application: A State-of-the-Art Review.
- Author
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Xue, Zhiwei, Niu, Shuangxia, Chau, Aten Man Ho, Luo, Yixiao, Lin, Hongjian, and Li, Xianglin
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ELECTRIC drives ,RENEWABLE energy sources ,PREDICTION models ,FAULT-tolerant control systems ,WIND power ,ELECTRIC propulsion - Abstract
Model predictive control (MPC) technology for multi-phase electric drives has received increasing attention in modern industries, especially in electric vehicles, marine electrical propulsion, and wind power generation. However, MPC has several challenges in controlling multi-phase electric drives, including the design of weighting factors, high computational complexity, large harmonic currents, heavy reliance on the system model, fault-tolerant control operation, common-mode voltage, and zero-sequence current hazards. Therefore, this paper gives a comprehensive review of the latest and most effective solutions to the existing major technical challenges and prospects for the future trends of MPC for multi-phase electric drives. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
8. Design Optimization and Comparative Study of a Novel Halbach Permanent Magnet Vernier Machine with Alternate Flux Bridge.
- Author
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Huang, Ziqi, Chau, Aten Man Ho, Niu, Shuangxia, Zhao, Xing, and Xue, Zhiwei
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PERMANENT magnets ,VERNIERS ,FINITE element method ,BRIDGE design & construction ,GENETIC algorithms ,COMPARATIVE studies - Abstract
The purpose of this paper is to investigate the effect of the alternate flux bridge combining Halbach array in Vernier machines. The key novelty is that integrated with the Halbach array PM, the alternate flux bridge design can not only provide a flux path for low-order harmonics but also effectively improve the torque density of the machine. Together with the other three traditional structures under the same overall size, current density, and PM usage, the proposed structure is optimized by genetic algorithm (GA) to maximize the average torque and minimize the torque ripple. With the winding configuration of full-pitch (FP) and short-pitch (SP), the back-EMF, efficiency, power factor, and other performances of four machines with different topologies are analyzed and compared, respectively. With 2D time stepping finite element analysis (FEA) and experimental verification, the torque density of the proposed design reaches 40.11 KNm/m
3 , which is significantly higher than that of its existing counterparts. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
9. Underwater Wireless Charging System of Unmanned Surface Vehicles with High Power, Large Misalignment Tolerance and Light Weight: Analysis, Design and Optimization.
- Author
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Niu, Songyan, Zhao, Qingyu, Chen, Haibiao, Yu, Hang, Niu, Shuangxia, and Jian, Linni
- Subjects
WIRELESS power transmission ,AUTONOMOUS vehicles ,INDUCTIVE power transmission ,SURFACE charges ,SUBMERSIBLES ,ELECTRIC charge ,BALANCE of power - Abstract
Wireless charging systems (WCSs) are considered very appropriate to recharge underwater surface vehicles (USVs) due to their safe, flexible, and cost-effective characteristics. The small depth of immersion of USVs allows a WCS operated at an mm-level distance using a dock. Resultant tight coupling between the transmitter and receiver is conducive to high power, yet faces a challenge to alleviating misalignment sensitivity. In addition, considering USVs' endurance, the weight of a WCS should be strictly limited. In this paper, a 6.0 kW underwater WCS is analyzed, designed, and optimized, which achieves a good balance of power capacity, misalignment tolerance, and onboard weight. A multi-receiving-coil structure is employed, which is crucial to large misalignment tolerance. On this basis, two types of coils adapting the hull shape of USV, viz., curved and quasi-curved coils, are devised and compared in case the hydrodynamic performance of USV is degraded. Finally, the weight of receiver is effectively reduced using bar-shaped ferrite without sacrificing the power capacity of WCSs. The results indicate a merely 8.73% drop in coupling coefficient with misalignment ranging from 0 to 100 mm. Moreover, ferrite use is reduced by 40.48 kg compared to a ferrite sheet, which accounts for 50.28% weight of the receiver. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
10. A General Pattern-Based Design Optimization for Asymmetric Spoke-Type Interior PM Machines.
- Author
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Huang, Jiahui, Fu, Weinong, Niu, Shuangxia, Zhao, Xing, Bi, Yanding, and Qiao, Zhenyang
- Subjects
PERMANENT magnet motors ,INTERIOR-point methods ,PERMANENT magnets ,MACHINERY ,GENETIC algorithms - Abstract
A novel asymmetric spoke-type interior permanent magnet (AS-IPM) machine is proposed in this paper. It utilizes the magnetic-field-shifting (MFS) effect to improve the torque performance, which achieves a high utilization ratio of both permanent magnet (PM) torque and reluctance torque. In addition, a general pattern of rotor topologies is proposed to represent all possible machine structures. Various rotor structures can be obtained by changing the design parameters of the general pattern. A non-dominated sorting genetic algorithm II (NSGA-II) is adopted to automatically search for optimal rotor configurations. With the aid of the optimization program, an asymmetric spoke-type rotor structure with improved performance is obtained. To showcase the advantages of the proposed machine, the electromagnetic performance is compared between a conventional spoke-type interior permanent magnet (S-IPM) machine and a proposed AS-IPM machine. The finite-element simulation results show that the optimal design of the AS-IPM performs a 7.7% higher output torque ripple due to the MFS effect while the total PM volume remains the same. Meanwhile, the torque ripple of the proposed structure is significantly reduced by 82.1%. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
11. Cogging Torque Minimization of Surface-Mounted Permanent Magnet Synchronous Motor Based on RSM and NSGA-II.
- Author
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Yu, Yinquan, Pan, Yue, Chen, Qiping, Zeng, Dequan, Hu, Yiming, Goh, Hui-Hwang, Niu, Shuangxia, and Zhao, Zhao
- Subjects
PERMANENT magnet motors ,PERMANENT magnets ,TORQUE ,RESPONSE surfaces (Statistics) ,FINITE element method ,SYNCHRONOUS electric motors - Abstract
A high-end permanent magnet (PM) synchronous motor's cogging torque is a significant performance measure (PMSM). During the running of the motor, excessive cogging torque will amplify noise and vibration. Therefore, the cogging torque must be taken into account while optimizing the design of motors with precise motion control. In this research, we proposed a local optimization-seeking approach (RSM+NSGA-II-LR) based on Response Surface Methodology (RSM) and Non-Dominated Sorting Genetic Algorithm-II (NSGA-II), which reduced the cogging torque of a permanent magnet synchronous motor (SPMSM). To reduce the complexity of optimization and increase its efficiency, the sensitivity analysis method was utilized to identify the structural parameters that had a significant impact on the torque performance. Second, RSM was utilized to fit the functional relationship between the structural parameters and each optimization objective, and NSGA-II was integrated to provide the Pareto solution for each optimization objective. The solution with a greater average torque than the initial motor and the lowest cogging torque was chosen, and a new finite element model (FEM) was created. On the basis of the sensitivity analysis, the structural factors that had the highest influence on the cogging torque were selected, and the RSM is utilized for local optimization to lower the cogging torque as much as feasible. The numerical results demonstrated that the optimization strategy presented in this study effectively reduced the cogging torque of the motor without diminishing the motor's average torque or increasing its torque ripple. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
12. Hybrid Reluctance Machine with Skewed Permanent Magnets and Zero-Sequence Current Excitation.
- Author
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Huang, Ziqi, Zhao, Xing, Wang, Weiyu, and Niu, Shuangxia
- Subjects
PERMANENT magnets ,ELECTRIC charge ,FINITE element method ,MACHINERY - Abstract
The reluctance machine is a potential candidate for electrical vehicle propulsion because of its reliable structure, low cost, flexible flux regulation ability, and wide speed range. However, the torque density is unsatisfactory because of the poor excitation ability and low stator core utilization factor. To solve this problem, in this paper, a novel hybrid reluctance machine (HRM) with the skewed permanent magnet (PM) and the zero-sequence current is proposed for electric vehicles. The skewed PM has two magnetomotive force (MMF) components with different functions. The radial MMF component provides extra torque by the flux modulation effect. The tangential MMF component can generate a constant biased field in the stator core to relieve the saturation caused by the zero-sequence current and thus improve the utilization factor of the stator core. Therefore, torque improvement and the relief of stator core saturation can be simultaneously achieved by the skewed PM. In this paper, the machine structure and principle of the proposed machine are introduced. And ultimately, the machine's electromagnetic performances are evaluated under different PM magnetization directions and zero-sequence current angles by using finite element analysis (FEA). [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
13. Optimal Design of Asymmetric Rotor Pole for Interior Permanent Magnet Synchronous Motor Using Topology Optimization.
- Author
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Wu, Huihuan, Niu, Shuangxia, and Fu, Weinong
- Subjects
- *
PERMANENT magnet motors , *TOPOLOGY , *SMOOTHING (Numerical analysis) , *ROTORS , *GENETIC algorithms , *TRUST - Abstract
As asymmetric interior permanent magnet synchronous motor (AIPMSM) has excellent performance but complicated topological structure, a novel high-resolution encoding and edge smoothing method is proposed for topology optimization of the asymmetric rotor of interior permanent magnet synchronous motor (IPMSM) in this study. This method aims to solve complex electromagnetic design problems with time-dependent performance through a multi-objective genetic algorithm (MOGA) integrated with a high-resolution encoding and edge smoothing method. The complex structure is represented by a high-resolution image-like matrix and then vectorized by the edge smoothing method. Therefore, the commonly used discrete binary encoded variables related to the finite element (FE) model are replaced with a vectorized topological structure and other control variables. In this sense, high-resolution matrix and edge smoothing methods are used for the first time to represent the rotor topology of AIPMSMs. Compared with the traditional topology optimization method, the proposed method has the advantage of expressing more complex and vectorized topological structures; meanwhile, the obtained performance is accurate and trustworthy using conventional FE simulation. Numerical results show that a stable convergence is achieved with the avoidance of checkerboards and material overlapping. It is shown that the proposed method can find solutions with better performances, in comparison with the reference model. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
14. Physics-Informed Generative Adversarial Network-Based Modeling and Simulation of Linear Electric Machines.
- Author
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Wu, Huihuan, Niu, Shuangxia, Zhang, Yunpeng, and Fu, Weinong
- Subjects
ELECTRIC machines ,GENERATIVE adversarial networks ,MAXWELL equations ,ELECTROMAGNETIC devices ,ELECTRIC machinery ,MAGNETIC fields ,SYNCHRONOUS electric motors - Abstract
The demand for fast magnetic field approximation for the optimal design of electromagnetic devices is urgent nowadays. However, due to the lack of a publicly available dataset and the unclear definition of each parameter in the magnetic field dataset, the expansion of data-driven magnetic field approximation is severely limited. This study presents a physics-informed generative adversarial network (PIGAN), as well as a permanent magnet linear synchronous motor (PMLSM)-based magnetic field dataset, for fast magnetic field approximation. It includes the current density, material distribution, electromagnetic material properties, and other parameters of the electric machine. Physics-informed loss functions are utilized in the training process, making the output governed by Maxwell's equation. Different slot-pole combinations of the PMLSM are involved in the dataset to extend the generalization of PIGAN. Some indicators for the further evaluation of magnetic approximation performance, including image-based metrics and calculation methods for the performance of electric motors, are presented in this study. Some challenges of magnetic field approximation using PIGAN are also discussed. The effectiveness of the physics-informed method is verified by comparing the magnetic field approximation results and the performance analysis results of the PMLSM with FEM, and the speed of PIGAN is approximately 40 times faster than that of FEM, while the accuracy is similar. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
15. Advances in Thermal Management Technologies of Electrical Machines.
- Author
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Wang, Qingsong, Wu, Yu, Niu, Shuangxia, and Zhao, Xing
- Subjects
HEAT pipes ,ELECTRIC machinery ,TECHNOLOGY management ,TEMPERATURE control ,COOLING systems ,MACHINERY - Abstract
Given the fact that the operation of electrical machines generates various loss components that finally become heat, developing advanced thermal management technologies is essential to control temperature increases and to guarantee safe operations. Meanwhile, the armature winding can stand larger currents when the machines are equipped with advanced cooling systems, which directly improves torque/power densities. This paper aims to provide a systematic review of the latest developments of advanced thermal management technologies of electrical machines. According to different heat dissipation mechanisms, the cooling systems studied in this paper are categorized into five major types: enclosed housing cooling, enhanced conductive cooling, embedded heat pipe cooling, direct oil cooling, and enhanced rotor cooling. The advantages and disadvantages of these cooling systems are researched and compared comprehensively. This study contributes to the revelation of insights on the thermal management of electrical machines and offers good guidance for the thermal management of electrical machines. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
16. Demagnetization Fault Detection and Location in PMSM Based on Correlation Coefficient of Branch Current Signals.
- Author
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Yu, Yinquan, Gao, Haixi, Chen, Qiping, Liu, Peng, and Niu, Shuangxia
- Subjects
FAULT location (Engineering) ,DEMAGNETIZATION ,PERMANENT magnets ,PERMANENT magnet motors ,ELECTRIC fault location ,STATISTICAL correlation ,FAULT diagnosis - Abstract
To address such challenges as an uncertain number of demagnetization poles of the permanent magnet synchronous motor (PMSM) and cases in which the fault cannot be located, this paper proposes a fault identification and location methodology based on the analysis of the motor stator current. First, the influence of the irreversible demagnetization of permanent magnets on the analytical model of the back electromotive force (Back-EMF) of the rotor in a single motor stator slot is analyzed. Moreover, considering the topology of the motor, the influence of the demagnetization fault on the stator phase current and branch current is analyzed. Since the stator phase currents cannot diagnose the partial demagnetization faults of PMSM with some topological structures, the stator branch current is selected as the signal for the identification and localization of the demagnetization fault. Secondly, the demagnetization fault diagnosis and mode recognition of the motor are carried out through the amplitude of the real-time branch current and the harmonic components of the PMSM. A sample database of demagnetization faults is established through calculation and normalization of the residual value of the stator branch current and the branch current of the healthy motor after demagnetization in one pole order. The fault threshold is obtained by analyzing the residual of the branch current of uniform demagnetization and the Pearson correlation coefficient of the fault sample database. Then, the correlation coefficient between the real-time branch current residual value of PMSM and the fault sample database is analyzed, and the number of demagnetization poles and the fault location are determined by the number and location of the calculated correlation coefficient exceeding the threshold. Finally, the feasibility and effectiveness of the proposed method are verified by the finite element analysis (FEA) results. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
17. Design and Analysis of a Linear Memory Machine for Ocean Wave Power Generation.
- Author
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Liu, Yulong, Zhang, Xiaodong, Niu, Shuangxia, Fu, Weinong, and Guo, Xinhua
- Subjects
OCEAN wave power ,OCEAN energy resources ,PERMANENT magnet generators ,LINEAR statistical models ,FINITE element method ,MACHINING ,PERMANENT magnets - Abstract
In this paper, a permanent magnet (PM) linear memory machine is proposed for ocean wave power generation. A notable feature of this machine is its online tunable mnemonic flux. This enables it to operate efficiently in a wide speed range and makes it suitable for the variable-speed wave-power generation. Moreover, this machine has both the PMs and the windings arranged in its stator so that it does not need slip rings or brushes. The proposed machine is also robust and cost-effective because it has a simple translator of slotted steel. In this paper, the configuration and working principle of the linear memory machine are firstly introduced. The results of a parametric analysis are presented to investigate the effects of the proposed machine's geometric parameters. The performance of the proposed machine is then analyzed using time-stepping finite element method (TS-FEM). [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
18. A Novel Dual-Structure Parallel Hybrid Excitation Machine for Electric Vehicle Propulsion.
- Author
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Zhang, Xiaodong, Zhao, Xing, and Niu, Shuangxia
- Subjects
PERMANENT magnets ,MAGNETIC fields ,DEMAGNETIZATION ,FEASIBILITY studies ,ELECTROMAGNETIC devices - Abstract
Magnetic field regulation is a difficult and long-existing issue in surface-mounted permanent magnet synchronous machines (PMSMs). To produce effective and efficient flux regulation for PMSMs, a new topology, named a dual-structure parallel hybrid excitation machine (DS-PHEM), is presented in this paper. In this machine, the rotating permanent magnet (PM) excitation and stationary DC field excitation are artificially arranged and designed at the inner and outer magnetic circuits, respectively. Therefore, a decoupling and parallel feature is obtained between two excitation sources. This machine integrates the merits of a brushless structure and theoretically infinite constant power range, as well as zero risk of demagnetization. In this paper, the machine configuration is introduced, mainly focusing on some important design criteria for electromagnetic integration, and the operating principles of flux control are also analyzed in detail. To further verify the feasibility of the proposed scheme, the overall electromagnetic performance of the proposed DS-PHEM is evaluated by using the time-stepping finite-element method. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
19. Comparative Analysis of Bearing Current in Wind Turbine Generators.
- Author
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Liu, Ruifang, Ma, Xin, Ren, Xuejiao, Cao, Junci, and Niu, Shuangxia
- Subjects
FINITE element method ,TURBINE generators ,WIND turbine efficiency ,APPROXIMATION algorithms ,ENERGY consumption - Abstract
Bearing current problems frequently appear in wind turbine systems, which cause wind turbines the break down and result in very large losses. This paper investigates and compares bearing current problems in three kinds of wind turbine generators, namely doubly-fed induction generator (DFIG), direct-drive permanent magnet synchronous generator (PMSG), and semi-direct-drive PMSG turbines. Common mode voltage (CMV) of converters is introduced firstly. Then stray capacitances of three kinds of generators are calculated and compared through the finite element method. The bearing current equivalent circuits are proposed and simulations of the bearing current are carried out. It is verified that the bearing currents of DFIGs are more serious than the two kinds of PMSG, while common mode current (CMC) of the direct-drive PMSG is much greater than the other two types of wind turbine generators. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
20. A Novel DC-Coil-Free Hybrid-Excited Machine with Consequent-Pole PM Rotor.
- Author
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Wang, Qingsong and Niu, Shuangxia
- Subjects
- *
MACHINERY , *ROTORS , *ELECTRIC currents , *ROTATING machinery , *ELECTRICITY - Abstract
This paper proposes a new DC coil free hybrid excited machine concept, which has no external field windings. The technical novelty is the integration of field windings and armature windings. DC bias current is injected into the excitation and the field windings in the traditional hybrid excited machine are eliminated. Compared with traditional hybrid-excited machines with additional field windings, the proposed machine can realize a higher slot utilization ratio, hence achieve a higher torque density and a wider flux adjusting range. Another advantage of the proposed machine is that the voltage drop associated with flux regulation is small due to the small DC resistance, and the torque generating capability at the flux regulating region can be improved accordingly. The rotor is specifically designed with magnet-iron sequences and a consequent-pole, in which the permanent magnet and iron pole are alternatively employed. A bi-directional flux modulating effect can be achieved, which can contribute to the magnetic coupling in the air-gap. Analytical derivation is used to describe the operating principle, and the proposed machine was optimally designed using the Tabu search algorithm. A prototype was made, and its performances investigated through experimental tests. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
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