• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.11
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• pp.1595-1600
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• 2012

This paper shows an improvement of the WRSM (Wound Rotor Synchronous Motor) by satisfying the voltage limit condition at high speed. After that, it compares the performance of the improved WRSM to that of the IPMSM (Interior Permanent Magnet Synchronous Motor). The comparison has been made under the condition where the dimension of the motor is identical to that of the IPMSM, having the rotor switched to a wounded rotor form. Moreover, this paper compares the Basic Model of the two motor, and estimates the parameters of the WRSM, thereby proposing the method to improve high speed performance. Furthermore, this paper presents the feasibility of switching the conventional motor into rare-earth-free motors for traction purpose.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2489-2491
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• 1998

The study of 3D image reconstruction re has developed along the progress of computer. Therfore Great deal of research on it have been done. 3D medical image reconstruction techniques are useful to figure out human's complex 3D structures from the set of 2D section. But 3D medical image reconstruction require a lot of calculation, it takes long time and expensive system. That gives a reason to the improvement of study on speed. In this paper. applying the interpolation to only the part which can appear as cube, I come up with a method that calculates the speed by reducing the a mount of calculation.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.832-837
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• 2006

ATC facility manipulates ground-on-board information, which transmits speed limit, varying as wayside environments - safety facility, track gradient, inclination, bridge and tunnel and other factors, installed for safe operation of trains on wayside. Efficientiation and automatification of operation and maintenance is being realized, by measuring if there are any erroneous information, using a measuring car. In this paper, we study in priority the methods for measuring accurately distinctive properties of internal malfunctions of track circuits, the performance decrease of condensers, and the unbalance of return cables, which are actually required for functionality improvement of high-speed line signal measure facilities, by measuring the unbalance of return current given because of damaged factors of external track circuits.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1146-1148
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• 2007

This paper proposes a method to improve the charging speed and discharging performance of a high voltage capacitor used in a portable medical device. The improvement of the charging speed was achieved by duty cycle control. The discharging performance was carried out by varying the phase duration and the leading edge voltage of the output according to the transthoracic impdedance of the patient. As a result, the improvement in the charging speed and the performance of the discharging parameters shorten the patient treatment time.

• Journal of the Korean Society of Industry Convergence
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• v.21 no.6
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• pp.439-444
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• 2018

The performance improvement in the high speed region for the sensorless based synchronous machine drive is discussed in the paper. Conventional dynamic overmodulation method in the vector controlled AC driver requires some calculation of maximum amplitude of the applying voltage vector to limit its amplitude, which leads to increase the calculation time of microprocessor. For low performance microprocessor, this might be impossible to complete the control loop within limited control time. Thus, to reduce the calculation time, the constantly limited amplitude for applying voltage vector is tried in this paper to drive sensorless based synchronous motor. Certainly, there exists some errors in amplitude and phase angle between inverter voltage and calculating voltage in the sensorless algorithm. But, this errors are too small to prevent the high speed sensorless operation within overmodulation region. The validities of the proposed method is proved by the experimental results.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.3
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• pp.244-249
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• 2008

This paper deals with speed control of DC servo motor using a Fuzzy tuning observer. Speed sensor detect a speed of rotor continuously. But it have a limit as a driving speed to detect speed precisely. So it is problem to improve the performance of the driving system. To solve the problem, it is studied to detect a speed of DC motor without sensor. In particular, study on the method to estimate the speed using the observer is performed a lot. In this parer, the gain of the observer is properly set up using the fuzzy observer. The fuzzy observer has a superior transient characteristic and is easy to implement compared the existing method is designed. It estimate the derivative of the armature current directly using the armature current measured in the DC motor. It estimate the speed of the rotor using the differentiation. It is proposed speed sensorless control method using the estimated speed. Optimal gain of Luenberger observer is set up using the fuzzy observer and adapted speed control of DC servo motor low speed operation. It is proved excellence and feasibility of the presented observer from the comparison tested a case with a speed sensor and a case without a speed sensor which used a highly efficient drive and 200W DC servo motor starting system.

• Journal of Korean Institute of Industrial Engineers
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• v.32 no.4
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• pp.298-313
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• 2006

Six sigma is focused on quality improvement through variation reduction, while lean is on process flow improvement and lead time reduction by waste elimination. However, lean cannot bring a process under statistical control and six sigma alone cannot dramatically improve process speed. Lean six sigma was developed to achieve faster rate of improvement in customer satisfaction, cost, quality, process speed, and invested capital. In this paper we present the importance of using value stream mapping and suggest a guideline on how to integrate lean and six sigma by is proposed.

• Journal of Power System Engineering
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• v.18 no.5
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• pp.129-136
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• 2014

This paper proposes improvement on sensorless vector control performance of a permanent magnet synchronous motor (PMSM) with sliding mode observer. An adaptive observer gain and second order cascade low-pass filter (LPF) were used to improve the estimation accuracy of the rotor position and speed. The adaptive observer gain was applied to suppress the chattering intensity and obtained by using the Lyapunov's stability criterion. The second order cascade LPF was designed for the system to escalate the filtering performance of the back-emf estimation. Furthermore, genetic algorithm was used to optimize the system PI controller's performance. Simulation results showed the effectiveness of the suggested improvement strategy. Moreover, the strategy was useful for the sensorless vector control of PMSM to operate on the low-speed area.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.9
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• pp.1589-1596
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• 2003

In this paper, we performed the improvement study for the dynamic characteristics enhancement of the motor stator coil vertical winding machine. The dynamic characteristics improvement was done by means of the optimized design and the weight reduction of the flyer configuration, modified design of the servo control system for the flyer and the former actuation, and the development of jump timing digital circuit for the reduction of former jumping error. As the results, the maximum winding speed pattern of the developed machine was attained up to 3000rpm and also reduced the jumping error. In conclusion, domestic design technology for manufacturing the motor coil vertical winding machine was established through this study.

• Journal of the Semiconductor & Display Technology
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• v.11 no.2
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• pp.33-38
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• 2012

The wafer positioning robot in the semiconductor industry is required to operate at high speed for the improvement of productivity. The residual vibration caused by the high speed of the wafer positioning robot, however, makes the life of the robot shorter and the cycle time longer. In this study, the input shaping and the path of the system are designed for the reduction of the residual vibration and the improvement of the cycle time. The followings are the process for the reduction and the improvement; 1) System modeling of the wafer positioning robot, 2) Verification of dynamic characteristics of the wafer positioning robot, 3) Input shaping plan using impulse response reiteration, 4) Simulation test using SIMULINK program, 5) Analysis of result.