• Journal of Electrical Engineering and Technology
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• v.1 no.1
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• pp.73-79
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• 2006

Conceptually, mechanical port of an electric machine can be doubled and the concept of dual-mechanical-port (DMP) will then give birth to a new breed of electric machines. In this paper, the various possible structures of DMP electric machine are discussed. Basic modeling and analysis issues related to the DMP electric machine are presented. An exemplary design of DMP machine is given and verified by FEM results. Potential applications and future research work are given to conclude the paper.

• Journal of Climate Change Research
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• v.7 no.1
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• pp.95-101
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• 2016

This study measured the amount of electricity consumed by the vending machines installed on campus and aim to come up with measures to address excessive consumption of electricity. We chose 10 universities located in the city of Seoul and Gyeonggi province and measured electricity consumption of 10 vending machines installed in each university. We then calculated annual electricity consumption of the machines based on previously calculated electricity consumption of 100 samples. According to the result of the calculation, it is estimated that the machines studied on consume 700 KWh a year. This amount could translate into approximately 3,000 tons of annual carbon emissions and 640 million KRW in annual electricity bills. It was also found that there is a significant difference between ordinary vending machines and machines certified for being eco-friendly and energy efficient, in terms of electric power consumption. It is expected that, if the ordinary machines are replaced with the eco-friendly and high-efficient machines, 640 KWh of electricity, 300 kg of carbon, and 61,640 KRW in electricity bills would be saved, which means 28% saving in energy, emissions and bills. In conclusion, we determined that, as one of the ways to reduce electric power consumption and carbon emissions, old vending machines on campus could be replaced with eco-friendly and high-efficient machines.

• Proceedings of the KIEE Conference
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• summer
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• pp.91-93
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• 2004

This paper is to develope the fast screening algorithm for on line transient security assessment. All generators are represented in a classical model and stability index is defined as a ratio between acceleration power and deceleration power Critical machines and remaining machines are identified based on stability index and aggregated into two equivalent machines. And finally equivalent machines are reduced into OMIB system then CCT is computed. The Proposed algorithm is applied to the KEPCO system and obtained the reasonable results compared with TSA Tool.

• Proceedings of the Korean Magnestics Society Conference
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• 2015.05a
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• pp.7-7
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• 2015

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.3
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• pp.272-275
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• 2014

An improved fuzzy Kalman filtering speed estimation scheme was proposed by means of measuring stator side voltage and current value based on vector control state equation of induction motor. The designed fuzzy adaptive controller conducted recursive online correction of measurement noise covariance matrix by monitoring the ratio of theory residuals and actual residuals to make it approach real noise level gradually, allowing the filter to perform optimal estimation to improve estimation accuracy of EKF. Meanwhile, co-simulation scheme based on MATLAB and Ansoft was proposed in order to improve simulation accuracy. Field-circuit coupling problems of induction motor under the action of vector control were solved and the parameter optimization accuracy was improved dramatically. The simulation and experimental results show that this algorithm has a strong ability to inhibit the random measurement noise. It is able to estimate motor speed accurately, and has superior static and dynamic characteristics.

• KEPCO Journal on Electric Power and Energy
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• v.4 no.2
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• pp.89-99
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• 2018

Downtime and malfunction of industrial rotor machines represents a crucial cost burden and productivity loss. Fault diagnosis of this equipment has recently been carried out to detect their fault(s) and cause(s) by using fault classification methods. However, these methods are of limited use in detecting rotor faults because of their hypersensitivity to unexpected and different equipment conditions individually. These limitations tend to affect the accuracy of fault classification since fault-related features calculated from vibration signal are moved to other regions or changed. To improve the limited diagnosis accuracy of existing methods, we propose a new approach for fault diagnosis of rotor machines based on the model generated by supervised learning. Our work is based on feature residual values from vibration signals as fault indices. Our diagnostic model is a robust and flexible process that, once learned from historical data only one time, allows it to apply to different target systems without optimization of algorithms. The performance of the proposed method was evaluated by comparing its results with conventional methods for fault diagnosis of rotor machines. The experimental results show that the proposed method can be used to achieve better fault diagnosis, even when applied to systems with different normal-state signals, scales, and structures, without tuning or the use of a complementary algorithm. The effectiveness of the method was assessed by simulation using various rotor machine models.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.3
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• pp.269-274
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• 2013

Fault-tolerant capability, wide speed range and overload capability are required in electric motors used in electric vehicles. In this paper, based on the analysis of the all poles wound and alternate poles wound flux-switching permanent-magnet machines, an optimization method is studied to reduce torque ripple. The method takes account of both flux-leakage and cogging torque. The simulation result shows that the method can reduce the torque ripple effectively. This study lays the foundation for the further application of FSPM in electric vehicles.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2347-2349
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• 2004

The iron loss in electric machines takes large part of machine losses and the reduction of iron loss brings the increase of the efficiency. In the rotating machines, however it is very difficult to calculate result because the measuring processes are very complex and laborious. As is well known, the relation between the flux density B and the magnetic field intensity H relation is not linear. For the iron loss, B and H must be measured and usually B becomes the reference wave(sine wave) and the following H is measured using H-coil. To make the B as sine wave, B is controlled by some devices. The error is controlled to become zero by the proposed algorithm which uses the bisection algorithm. The experiments are compared with the simulation results, and they show acceptable agreements.

• Proceedings of the KIEE Conference
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• 2004.10a
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• pp.49-51
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• 2004

The iron loss in electric machines takes large part of machine losses and the reduction of iron loss brings the increase of the efficiency. In the rotating machines, however it is very difficult to calculate the iron loss and to get the exact experiment result because the measuring precesses are very complex and laborious. As is well known, the relation between the flux density B and the magnetic field intensity H relation is not linear. For the iron loss, B and H must be measured and usually B becomes the reference wave(sine wave) and the following H is measured using H-coil. To make the B as sine wave, B is controlled by some devices. The error is controlled to become zero by the proposed algorithm which uses the bisection algorithm. The experiments are compared with the simulation results, and they show acceptable agreements.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.19-26
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• 2001

There passed almost 15 years since our sound quality studies in Japan related to the emitted noise from the industrial products have been started. The sound under consideration are interior and exterior noise from cars, noise from the electric appliances such as electric shavers, electric cleaners and washing machines and the sound emitted from earth moving machines and etc. After a little while since sound quality studies have been started, the products with better sound are gradually on sale on the market.