• Journal of Power Electronics
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• v.11 no.1
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• pp.105-111
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• 2011

By having accurate knowledge of the magnetic field distribution and the thrust calculation in linear synchronous motors, assessing the performance and optimization of the motor design are possible. In this paper, after carrying out a performance analysis of a single-sided wound secondary linear synchronous motor by varying the motor design parameters in a layer model and a d-q model, machine single- and multi-objective design optimizations are carried out to improve the thrust density of the motor based on the motor weight and the motor efficiency multiplied by its power factor by defining various objective functions including a flexible objective function. A genetic algorithm is employed to search for the optimal design. The results confirm that an overall improvement in the thrust mean, efficiency multiplied by the power factor, and thrust to the motor weight ratio are obtained. Several design conclusions are drawn from the motor analysis and the design optimization. Finally, a finite element analysis is employed to evaluate the effectiveness of the employed machine models and the proposed optimization method.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.4
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• pp.399-404
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• 2012

In this paper, a stator-separated axial flux-switching hybrid excitation synchronous machine (SSAFHESM) is presented, of which the structure and operational principle are introduced. The magnetic field distribution under different excited currents is analyzed, and some characteristics including flux-linkage, EMF and field control ability are studied by finite element analysis (FEA). Tests are carried out on a 12/10-pole prototype machine to validate the analysis results, and an excellent agreement is obtained.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.23-24
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• 2013

In recent years, ISG (Integrated Starter and Generator) system receives a great attention for electric electrification of normal gasoline vehicle. As a cost-effect machine design, an ISG without a permanent magnet is considered. A 12slot-10pole field-excitation flux-switching synchronous machine (FEFSSM) is designed and analyzed via JMAG. The active parts such as the field excitation coil and armature coil are located on the stator. The rotor part consisting of single piece iron makes it more robust and suitable to apply for high speed motor drive system application coupled with reduction belt. The design target is the motor with a maximum torque of 40Nm, a maximum power of 10kW and a maximum speed of 14000 rpm. In this paper, design optimization method is proposed for high torque capability.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.8
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• pp.1461-1471
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• 2002

Linear motor has a lot of advantages in comparison with conventional feed mechanisms: high velocity, high acceleration, good positioning accuracy and a long lifetime. An important disadvantage of linear motor is its high power loss and heating up of motor and neighboring machine components in operation. For the application of the linear motors to precision machine tools an effective cooling method and thermal optimizing measures are required. In this paper Finite-Element-Method for the thermal behavior of synchronous linear motor is introduced, which is useful for the design and manufacturing of linear motors. By modeling the linear motor the orthotropic physical properties of the sheet metal and windings were considered and convective coefficient in the water cooler and to the surroundings was defined by analytical and experimental method. The calculated isothermal lines could analyze the heat flow in the linear motor.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.882-883
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• 2011

This paper deals with comparison on Electromagnetic losses of slotted and slotless high-speed PM Machine for Micro Turbine. Losses are consist of core losses, copper losses and eddy current losses. We are using both analytical method and 2D Finite Element Method for more detailed losses analysis. And then We compare Electromagnetic losses of slotted and slotless PM synchronous machine. This machine has designed of a generator of 800W, 400000rpm and a starter of 400W, 200000rpm.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.8
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• pp.482-492
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• 2002

This paper deals with overvoltage stresses in the field circuit of synchronous machine connected to HVDC terminal. A load rejection of the HVDC may cause generator in the station to become self-excited, resulting in a severe system overvoltage. This paper shows that violent field current oscillations can be produced by resonance between the machine inductance and the terminal capacitance. As most conventional excitation system do not allow reverses current, new topology of excitation system to allow reverse current is proposed. the proposed system can limit the rate of rise of terminal voltage during conditions of self excitation. Apart from these simulations, the nature(Magnitude and frequency) of the field transient state is explained mathematically. Finally, the EMTDC program is used for the simulation studies.

• Journal of Power Electronics
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• v.9 no.2
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• pp.188-197
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• 2009

This paper presents an adaptive flux observer to estimate stator flux linkage and stator inductances of an interior permanent-magnet synchronous machine considering magnetic saturation. The concept of static and dynamic inductances due to saturation is introduced in the machine model to describe the relationship between current and flux linkage and the relationship between their time derivatives. A flux observer designed in the stationary reference frame with constant inductance is analyzed in the rotor reference frame by a frequency-response characteristic. An adaptive algorithm for an on-line inductance estimation is proposed and a Lyapunov-based analysis is given to discuss its stability. The dynamic inductances are estimated by using Taylor approximation based on the static inductances estimated by the adaptive method. The simulation and experimental results show the feasibility and performance of the proposed technique.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.276-279
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• 2003

The superconducting synchronous machine(S.S.M) including generator and motor has different electromagnetic structure from the conventional machine. With the help of superconductor having much higher operating current density than normal conductor, S.S.M can eliminate most of iron core filling inside of the conventional machine. This air-cored structure could be analysed and designed theoretically based on 2-dimensional(2-D) magnetic field distribution assuming that the windings are extended infinitely toward the axial direction. However the actual structure of S.S.M has the end regions interconnecting the straight parts of the same cross-section with the 2-D model. Therefore, this actual 3-D model has smaller field distribution than the 2-D model. In this paper, we consider the effect of the end regions on the output of a HTS model motor and suggest more accurate design approach through comparison of 2-D and 3-D magnetic field analysis.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.3
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• pp.313-320
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• 2013

The fractional slot windings are widely used in rotating machine in order to increase the flexibility of design and improve the voltage waveform. However, the MMF wave of fractional-slot windings are found to contain unique harmonic component, which are designated as even order space flux harmonics, fractional number flux harmonics, or both. They may cause stray loss and stator core vibration. This paper proposes new winding methods "novel interspersed windings" and "expanded group windings" to reduce these harmonics. The advantages of two proposed windings are verified by using numerical analysis and measurement test of winding model.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.113-115
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• 1995

The calculations of the temperature rise in the armature have long been considered among some of the most important problems in the design of the rotating machine. Despite the many methods of calculation propose, very few have been used in the actual design. In most cases, These methods are inadequate for measuring a wide range of temperature distribution because of the complicated structure of the machine. In this paper, the armature is divided into seven portions, and the thermal equivalent circuit is introduced as a simulation of the armature. The test machine is 1000Kw salient-pole synchronous generator.