Huai-Cong Liu

Study on the High Efficiency Design of IE4 Synchronous Reluctance Motor Replacing IE3 Induction Motor

In accordance with global energy conservation policies such as MEPS(Minimum Energy Performance Standard), electric motor industry is moving to super-high-efficiency machines and research to develop IE4 (International Energy Efficiency Class4) motors has been launched. In this situation, SynRM (Synchronous Reluctance Motor) has been attracting attention in place of induction motor which hardly provides super premium efficiency. As a result, much research on SynRM is being performed at home and abroad. Also, some products have already been appearing in the market. Compared to induction motor, SynRM has better efficiency per unit area and wider operating range. Although the utilization of control system in synchronous motor results in higher prices, we still need to concentrate on developments of SynRM so as to comply with the new policies. This study demonstrated the electromagnetic design methods of super-premium SynRM while maintaining the frame of existing IE3 induction motor for blower . We documented the design procedures for generating high saliency which is the most essential and mechanical stress analysis is also treated. In conclusion, we proved the validity of our design by manufacturing and testing our SynRM models.

Design and Analysis of the Eddy Current Brake with the Winding Change

This paper is a study of the eddy current brake designed to replace the air brake of railway application. The eddy current brake has the advantage of being able to take a high current density compared to the other application because this brake is used for applying brakes to the rolling stock for a shorter amount of time. Also, this braking system has the merit of being able to take a high current density at low speed rather than at high speed, because the heat generated by the low speed operation is less than that of the high speed operation. This paper also presents a method of improving the output torque of the eddy current brake at low speed operation through a change of the winding as well as the basic design.

Design of Permanent Magnet-Assisted Synchronous Reluctance Motor for Maximized Back-EMF and Torque Ripple Reduction

This paper proposes the optimization of the shape and size of a ferrite magnet and the arrangements necessary to reduce torque ripple and maximize back electromotive force (B-EMF) in a permanent-magnet-assisted synchronous reluctance motor. First, four different models of general magnet arrangements were selected, and analysis using the finite-element method was performed under open circuit and load operations for each of the four models. Next, the relationship between the cogging torque and the torque ripple was analyzed, considering the segment saturation phenomenon. Then, based on the initial model, the design was optimized for maximum B-EMF and minimum torque ripple, and the total harmonic distortion was measured. Finally, the validity and superiority of the optimized design were confirmed by manufacturing a prototype motor and performing the experiment.

Optimal rotor structure design of claw-pole alternator for performance improving using static 3D FEM coupled-circuit model

This paper presents a study on static 3D finite element method (FEM) coupled-circuit model of a 3Kw claw-pole alternator. To derive the Optimal rotor structure, Magneto static 3D FEM used to define representation of the airgap flux density and phase inductance including magnetic saturation effect and leakage flux. Coupled-circuit model is alternator/rectifier system which based circuit analysis program. The static 3D FEM coupled-circuit model compare with transient simulation result, which proves to be coherent.

Design of high-end SynRM based on 3D printing technology

This paper intends to verify, through actual fabrication and test, that 3D printing technology, which is one of the top 10 most promising future technologies, can be grafted onto motor industry. A complicated rotor geometry of SynRM, a non-rare earth motor, was designed and fabricated, using 3D printing technology. This paper tried to test the validity of its research by FEM analysis and load test in comparison with the existing SynRMs.

Design and Analysis of a Double-Layer Magnetic Circuit Structure for High-Force Density Hybrid Fuel Injector

This paper proposes the design and analysis of a double-layer magnetic circuit structure for a high-force density hybrid fuel injector. In general, fuel injector models have disadvantages such as a significant leakage flux and magnetic saturation; therefore, a finite-element method is used to detail the model design and reduce the leakage flux from the electromagnet pole to the lead pipe. This change can help improve the fuel injector performance. In addition, a permanent magnet (PM) is inserted to increase the force density. Moreover, the no-load performance and demagnetization characteristic of the injector are analyzed according to the injector’s working environment. The optimized hybrid fuel injector model with a PM shows substantially improved performance compared to a conventional design.

Eddy Current Brake With a Two-Layer Structure: Calculation and Characterization of Braking Performance

This paper presents a new method for calculating the braking force of a drum-type eddy current brake with a two-layer structure. The drum-type eddy current brake should have a structure that improves the braking force by applying a material with high conductivity inside the drum because the eddy current loss generated from the drum is used as the braking force. In addition, because the eddy current brake operates at various speeds while braking the vehicle, it is necessary to grasp the braking force according to the speed. Furthermore, because the material of the drum is composed of non-laminated iron having conductivity, the skin effect and the armature reaction phenomenon appear, and the skin depth and the air-gap flux density are different depending on the braking speed. In this paper, the value of the eddy current loss of the eddy current brake with a copper coating inside the drum is newly presented and compared with the finite-element analysis results. In addition, the change in the speed–torque curve according to the conductivity value of the drum and inner coating material are shown. Finally, an experiment was conducted to compare and verify the characteristic curve of the eddy current brake obtained from the newly derived equations.

Design of High-End Synchronous Reluctance Motor Using 3-D Printing Technology

This paper contains the results of actually applying to motor development the 3-D printing technology, which is one of noteworthy technologies to lead industries in the future. The current level of 3-D printing technology was identified, synchronous reluctance motor was designed and fabricated on the basis of the technology, and experiment was carried out to verify the design and fabrication. The comparative analysis between the existing model and the proposed model was carried out by finite element method analysis and experiment, and it shows the possibility that 3-D printing technology can be applied to the motor industry.

PM arrangement design of PM-assisted synchronous reluctance motors for maximize back-EMF and cogging torque reduction

This paper proposes the optimization of an isotropic ferrite magnet magnetization direction and arrangements to enable reduces the cogging torque and maximize back-EMF of PMA-SynRM. Firstly, four different models of general magnet arrangement are selected, and then FEM analysis is carried out with four different magnetization directions for each of four models. Secondly, based on the initial model, optimization design for maximum back-EMF and minimum cogging torque and THD is performed. Thirdly, in order to ensure the safety of the design the PM characteristics such as demagnetizing force, PM energy product, air-gap flux density and stiffness analysis of rotor structure are analyzed by FEM. Finally, validity and superiority of the optimization design are confirmed by manufacturing the prototype motor and performing the experiment.

Bubbles and blisters impact on die-casting cage to the designs and operations of line-start synchronous reluctance motors

This paper includes an investigation of the starting capability of a high efficiency synchronous reluctance motor for direct on-line industrial applications. The approach is to design and optimal of multi-barriers inside rotor to achieve the starting properties of an line start synchronous reluctance motor (LS-SynRM) and the steady-state performance. Using an equivalent circuit on the basis of symmetric field theory, conditions are found for balanced operation at rated conditions and for state/rotor copper loss minimization in the rotor. The optimal model of LS-SynRM is compared and evaluated against a same size induction motor (IM). In addition, the shape of cage bar in LS-SynRM rotor will be analyzed, along with the generated motor torque and loss assessment. As the related die-casting processes on the end-ring and of cage bar achieve desired low rotor resistance, their impacts to the synchronization of LS-SynRM due to bubble/blister during die-casting will also be thoroughly evaluated. Assisted by finite-element analysis (FEM), the results clearly indicated that the rotor slots optimal with die-casting process on the rotor must be introduced for LS-SynRM designs with better steady-state performance and higher efficiency requirements.