1,721,156 research outputs found
High Performance Synchronous Reluctance Machines: Design and Applications
Full text linkAs one of the oldest machine topologies, the concept of synchronous reluctance (REL) machine can be traced back as early as 1900s. In the last 20 years, particularly, the REL machines have attracted more and more attention in both academic and industrial fields. Without permanent magnets and rotor bars, the rotor construction of the REL machine is more robust than either permanent magnet (PM) machines or induction machines (IMs). In addition, it achieves the merits of low cost, low maintenance, and high reliability. All these features reveal the REL machine to be an attractive alternative to the widely used machine topologies. Therefore, the investigation of REL machines is essential, and specific applications will be of great interest. In this thesis, the design and analysis of high performance REL machines are developed and discussed. Furthermore, two particular applications are investigated: REL motors for electric vehicle (EV) applications and self-excited reluctance generators (SERG) for isolated wind applications.
To start with, the transversely-laminated anisotropy rotor type with multiple flux-barriers is chosen to be designed and analyzed. More specifically, a detailed parametric analysis of this kind of rotor geometry is carried out, which aims to suggest an automatic drawing and simulating procedure. The shape of flux-barriers is selected to achieve both high d-axis inductance and low q-axis inductance. Methods to properly design the geometry of barrier ends and PMs are adopted. Some tuning steps are suggested in order to achieve the high performance design. Such a procedure is then used to rapidly analyze the impact of some rotor parameters on the machine performance, in order to provide a guideline for the preliminary design of the REL machine. After that, as a practical example, a REL motor according to the dimension of a commercial motor is designed. Certain design procedures are followed, and optimization is also carried out. The performance comparisons between the optimized REL motor and the commercial product are given. Merits and defects of the REL machine for EV application are highlighted.
The study on SERG starts with the recognition of the steady-state performance, both analytically and experimentally. The conditions related to successful self-excitation in SERG, such as required capacitance, rotor residual magnetism, rotor acceleration and pre-charging capacitors, are investigated. The possibility to adopt self-excited PM-assisted reluctance generator is also dealt with, and the performance comparison with SERG is made. The effect of some design parameters on the performance of the PMAREL generator is analyzed. Referring to wind applications, the method to maintain the generated voltage constant at variable speeds is proposed. Finally, the prediction of the "optimal capacitor and resistor combination" that achieves the maximum utilization of the mechanical power produced by the wind turbine will be presented
Comparative Study of Non-Rare-Earth and Rare-Earth PM Motors for EV Applications
Full text linkRecently, non-rare-earth motors are attracting more and more attention due to the booming of the electric vehicle (EV) market and, more importantly, the increasing price of the rare-earth magnet material. This paper focuses on the performance comparison among a commercial interior permanent magnet (IPM) motor and two non-rare-earth motors, including a synchronous reluctance motor (SynRM) and a permanent-magnet-assisted synchronous reluctance motor (PMaSynRM). The design procedure to develop a high-torque-density, low-torque-ripple and high-efficiency SynRM is presented. Combined with a developed automatic modeling and simulation procedure, the finite element analysis (FEA)-based differential evolution (DE) algorithm is introduced for the SynRM rotor optimization. In order to fully inspire the potential of the SynRM, a novel method to optimize the motor split ratio is proposed under the constraint of the copper loss. In addition, different slot–pole combinations are investigated to maximize the motor torque, and the rotor structure is also dealt with towards the centrifugal stress at the maximum operating speed. Finally, the motor performance comparison is carried out, and the results show that although the SynRM achieves almost 61% cost savings, its poor torque capability, power factor and flux weakening (FW) capability are non-negligible defects. On the contrary, the PMaSynRM exhibits excellent features for the EV applications in terms of cost, torque density, efficiency and FW capability. This paper presents a novel split ratio optimization method for the optimal SynRM/PMaSynRM design and demonstrates the characteristics of the IPM motors, SynRMs and PMaSynRMs for EV applications
Parametric Design and Optimization of Magnetic Gears with Differential Evolution Method
No full textRecently, magnetic gears have drawn wide attention due to their inherit merits, such as high torque density and overload protection. In this paper, an analytical calculation based on MMF-permeance theory is adopted to analyze the modulation effect in magnetic gear. After that, an automatic drawing procedure is built to rapidly analyze the parameters. The effects of some key parameters on magnetic gear performance are investigated, including air slot opening to pole pitch ratio c0, magnet-arc to PM pole pitch ratio and PM thickness hm. In particular, three types of steel pole-pieces are considered, which are radial slots, parallel teeth and parallel slots. At last, a global optimization design is carried out by using differential evolution algorithm, and some useful suggestions are given for the design and optimization of coaxial magnetic gear
A Fast Permanent Magnet Width Determination Method for Multiple-Layer Flux-Barrier Permanent Magnet-Assisted Reluctance Machines
No full textIn order to maximize the reluctance torque component, multiple-layer flux barriers are usually employed in permanent magnet-assisted synchronous reluctance (PMAREL) motors. However, the permanent magnet (PM) dimension of each layer should be carefully designed to achieve the best performance with the minimum PM material. This article investigates this issue and proposes a method to define the PM width according to the sinusoidal no-load airgap flux density distribution. First, the accuracy of the no-load magnetic circuit for airgap flux density calculation is verified with finite element analysis (FEA), considering single or multiple flux-barriers per pole. The effects of the location, width, and thickness of the PM are investigated separately. Then the PM width is derived by the equations developed from the no-load magnetic circuit. The proposed method reduces both the PM mass and the torque ripple. This approach provides a fast and efficient way to determine the width of the magnets in different layers of flux barriers
Comprehensive Design of a Permanent-Magnet-Assisted Reluctance Machine for an Electric Vehicle Application
No full textRecently, permanent magnet (PM)-assisted reluctance (PMAREL) machines are gaining increasing attention for traction applications to reduce magnet consumption. In this article, a comprehensive design methodology is applied to design a PMAREL machine for an electric vehicle (EV) propulsion application. The design method includes both electromagnetic and mechanical analyses. A finite element analysis (FEA)-based differential evolution (DE) algorithm is adopted to find the best reluctance (REL) rotor geometry. The PM dimensions are calculated analytically, which allows a fast identification for the initial design. An FEA model for mechanical analysis is developed, and some remedial techniques are adopted to improve the mechanical stress. The design procedure starts with the selection of the stator split ratio. Then it continues with REL optimization and PM dimension determination. Finally, the rotor structure is modified iteratively based on electromagnetic and mechanical performance. FEA validations show that the designed PMAREL motor satisfies the requirements of the targeted propulsion application
A Torque Ripple Reduction Method for the Synchronous Reluctance Machines With Mirror Asymmetric Rotor Laminations
No full textThe synchronous reluctance motor (SynRM) possesses a simple structure and low cost. However, its application is hindered by high-torque ripple. Traditional asymmetric designs can effectively suppress torque ripple. However, it often exhibits poor performance during reverse rotation and lacks theoretical guidance. In this article, an analytical model is developed to establish the relationship between torque and flux barrier end angles. A novel technique is then proposed to mitigate the torque ripple of the SynRM by introducing mirror asymmetric rotor laminations. These laminations feature asymmetrically designed flux barriers in one pole and periodically symmetric ones in the adjacent pole, arranged in a mirrored stacking configuration. The proposed technique is implemented in practical machines, and the effectiveness of the proposed method is validated through experimental tests
Geometry analysis and optimization of PM-assisted reluctance motors
No full textIn this paper, a detailed geometry analysis of the rotor structure is presented, for both synchronous reluctance and PM-assisted reluctance motor, in order to suggest an automatic procedure to draw the rotor structure. The shape of flux barriers is selected to achieve both high d-axis inductance and low q-axis inductance, in order to obtain high output torque. Methods to properly design the geometry of the end of each barrier and PMs are adopted. In order to draw a rotor with proper shape, different modifications are discussed. After that, such a drawing procedure is used to rapidly analyze the impact of some geometry changes on the machine performance. The analyzing process starts from a reluctance motor, considering the number of barriers, insulation ratio, split ratio and slots per pole per phase. Then, the PMs are inset into flux barriers and the effect of PM width on torque, power factor and flux weakening capability is investigated. At last, the demagnetization limit under overload operations is analyzed
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