• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.540-545
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• 2001

In case of small motors, coil bundle occupies a large portion of stator in view of mass and volume as well as dynamics. It is observed through modal test on the stator of an IPM BLDC (interior permanent magnet brushless direct current) motor that coil bundle wound on the stator core causes the first and second natural frequencies to decrease by about 20-30% compared with those of bare stator. Especially the third natural frequency is newly observed below 3 KHz, which is not observed on the bare stator. It is found that at the third mode the end-coil and the core vibrate out of phase in radial direction. In this paper, the stator is dynamically modeled in terms of the core and the coil bundle consisting of the end-coil and the slot coil based on the above observations for the prediction of dynamic properties. The core can easily be modeled using finite element method with its actual material properties and geometric shape. The concept of equivalent bending stiffness is used for modeling of the end-coil so that predictions may match with the measured natural frequencies for the end-coil cut out of the stator. Although the same concept can be applied to the slot coil, separation of the slot coil from the stator is impractical. Therefore, equivalent bending stiffness of the slot coil is determined through iterative comparisons with the measurements of natural frequencies of the stator with the slot coil in it.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.187-190
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• 2009

A multiple pulse rocket motor distributes the thrust energy more effectively compared to typical rocket motor as providing subsequent thrusts by the pulse motors of the missile. The pulse rocket motor is the advanced technology to improve an end game capability of the missile by increasing the range and final velocity. A pulse separation device is the core part of the pulse motor. The pulse separation device of bulkhead type was designed and developed. The elastic-plastic structural analysis of the bulkhead and rupture disc was conducted. Several air tests were also conducted to confirm the structural safety and acceptability about the design concept. Test results were compared with the analysis results, which showed reasonable agreements.

• Asia Marketing Journal
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• v.16 no.1
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• pp.215-228
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• 2014

The automotive industry plays a significant role in the global economy. One of the reasons is that this industry compasses every aspects of the value chain - from raw materials to design and development, manufacturing, sales and services, and even disposal. Thus, the industry needs significant upfront capital investment and requires years of R&D and market development. As a result, this industry is dominated by a handful of global players and it is not easy for a new entrant to enter this industry. Furthermore, success is even more difficult to achieve. How did Hyundai Motor make it in this tough marketplace? Can it continue against all odds? The CAGR for last 5 years is 12% and it stands at 6th in the world. Compared to other global brands, Hyundai has geographically well-balanced sales portfolio. The quality improvement is outstanding. The brand performance follows these quality and sales improvements. Yet, the global competition is ever intensifying. Now, it is the time to step up once more. The next strategic goal needs fundamental shift toward brand and marketing-focus. In constructing global marketing strategy, Hyundai Motor's vision is "Lifetime partner in mobility and beyond" and its goal is global top 3 brand by year 2015 through modern premium brand image and selling 5 million vehicles. The target brand positioning of Hyundai Motor is the leading position in premium dimension and stylish/modern dimension. The global brand strategy framework is based on the brand direction of "Modern Premium" and is designed to deliver core brand identity (i.e., Simple, Creative, Caring) to customers. In order to manage brand performance, Hyundai's marketing platformalso includes marketing performance management, brand performance management, and market driven organization. From this diagnosis, Hyundai Motor is well posed to build a strong brand. Nevertheless, there are still challenges ahead from consumer, technology, competitor, and macro-environment perspectives. To overcome these threats, the bases of competition for all successful automotive brands are various differentiation factors, including technology, performance, value proposition, or heritage. Hyundai Motor is well prepared so far. However, it is not tested against time yet whether Hyundai can overcome these unforeseeable major threats. Hyundai is trying to find the solution from a strong brand, while believing in "New Thinking. New Possibilities."

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.9
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• pp.1003-1012
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• 1992

This paper presents and analysis method for designing a squirrel cage induction motor, which is aimed at analyzing the dynamic characteristics of magnetic field. This scheme is capable of estimating the effects of slot harmonics due to the rotation of rotor by utilizing Macro-airgap element combination, Voltage source treatment and Time difference algorithm. Furthermore, this strategy presents and approach which effectively compensates for end-ring of rotor. And direct convergence method is applied for considering a magnetic nonlinearity in core. In addition to the precision and the convergence study of algorithm, comparisons with experimental values prove the accuracy of this analysis method.

• Proceedings of the KIEE Conference
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• 2003.10b
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• pp.128-130
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• 2003

For electrical machine designers, core loss data are usually provided in the form of tables or curves of total loss versus flux density or frequency. The aim of this work is to propose a mathematical model for the iron losses prediction in soft magnetic material$ with any frequency and flux density. In this paper, three formulas for calculating the iron loss coefficients are discussed. And the coefficients are applied to calculate the iron loss of the 25kW high speed motor.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.9-12
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• 2003

Brushless do motors have been replacing brush type motors in machine tool and robotics applications over the last number of years This Paper deals with the design and application of the slot-less permanent magnet synchronous motor (PMSM). The slot-less PMSM eliminates rotational cogging torque due to permanent magnet preferred positions decreases core loss and thus increases efficiency, provides excellent torque-to-volume and power-to-volume ratios, and has a linear current versus torque relation. The PMSM with slot-less stator is designed and manufactured, which will be used for high speed and high efficiency application such a medical instruments.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.607-611
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• 1992

This paper presents the methods in improving the efficiency using of magnet wedge. After the energy crises of 1970's, more emphasis was placed on higher efficiencies. Efficiency of an induction motor can be improved by reducing the total losses, copper, losses, iron or core losses etc. However high efficiency designs result, in larger size and cost than standard motors. In the methods of the reducing the losses, ripple losses of slot flux can be reduced by using the magnet wedge, but the starting torque decrease by means of increasing of leakage reactance.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.973.1_974.1
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• 2009

One of the most important technical improvement required for ropeless elevator system to become practical is the improvements in overall system efficiency. Moreover, the predominant drawback of permanent magnet (PM) linear synchronous motor (LSM) is large detent force. Therefore, for the given volume the selection of high power density PM-LSM with low detent force is very imperative. In this paper, we will investigate the characteristics of thrust and detent force of PM-LSM under different motor topology structure. Finally, the long stator double-sided iron core type PM-LSM with fractional slot winding is the best choice for the ropeless elevator system.

• Journal of Electrical Engineering and Technology
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• v.4 no.4
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• pp.515-520
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• 2009

According to the operating characteristics of pump applications, they should exhibit high efficiency and energy saving capabilities throughout the whole operating process. A novel efficiency optimization control strategy is presented here to meet the high efficiency demand of a variable speed Permanent Magnet Synchronous Motor (PMSM). The core of this strategy is the excellent integration of mended maximum torque to the current control algorithm, based on the losses model during the dynamic and the grade search method with changed step by fuzzy logic during the steady. The performance experiments for the control system of a variable speed high efficiency PMSM have been completed. The test results verified that the system can reliably operate with a different control strategy during dynamic and steady operation, and the system exhibits better performance when using the efficiency-optimization control.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.3
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• pp.509-515
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• 2009

When a squirrel cage induction motor is loaded, the magnetic noise can increase depending on the load current. It is due to the variation of air gap harmonic fluxes from the rotor current induced by loading. This unfavorable noise can be anticipated by analysing the radial force waves in the air gap, the mode shapes of them, and stator core natural frequencies at each mode. With the experimental tests with the different rotor slot numbers, the variation of magnetic noise depending on the load current is studied and the method to reduce the magnetic noise is suggested with the newly developed magnetic noise analysis program.