• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.2
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• pp.195-201
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• 2015

An electric excavator consumes battery energy to drive an electric motor attached to a hydraulic pump to generate hydraulic power. In a conventional hydraulic excavator, the hydraulic pump is controlled by regulators, which are used to optimize the diesel engine efficiency. Because of a lack of battery energy capacity, an electric excavator controller should consider not only the electric motor efficiency but also the hydraulic pump efficiency. Thus, electric motor and hydraulic pump efficiency maps were constructed. An optimal operating map (OOM) was created based on the most efficient operating points under each input condition. An integrated control algorithm controlled the speed of the electric motor and displacement of the hydraulic pump according to the OOM. To confirm the utility of this algorithm, a model-in-the-loop simulator for the algorithm with an electric excavator was established. The simulation results showed that the integrated control algorithm improved the energy efficiency of an electric excavator.

• Journal of Power Electronics
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• v.6 no.4
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• pp.347-355
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• 2006

A new control method for precision robust position control of a permanent magnet synchronous motor (PMSM) is presented. In direct drive motor systems, a load torque disturbance directly affects the motor shaft. The application of the load torque observer is published in using a fixed gain to solve this problem. However, the motor flux linkage cannot be determined precisely for a load torque observer. Therefore, an asymptotically stable adaptive observer base on a deadbeat observer is considered to overcome the problems of unknown parameters, torque disturbance and a small chattering effect. To find the critical parameters the system stability analysis is carried out using the Liapunov stability theorem.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.335-338
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• 2005

Starting with the development of environmentally friendly electric controlled engine, sensors have played an increasing role in automotive technology. Electric power steering (EPS) systems are more and more replacing hydraulic systems. To improve fuel economy, the power assistance is provided by an electric drive. In this paper, development of a unique torque sensor for EPS is introduced. A capacitive type torque sensor is concluded to be suitable for EPS because its output is accurate, linear and robust against the variance of temperature, and patents have not applied so much.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.40-43
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• 2003

An electric propulsion system integrated with the ship service distribution system offers the naval architect considerable flexibility, and often the choice of a more affordable ship to acquire and operate as compared to a segregated mechanical drive option. United States of America navy announced in 2000 that they selected the electric propulsion system on next generation warship. Specially there is excellent advantages in superconductivity motors which can have higher efficiency, less vibration and noise, smaller dimensions compared with the conventional motors. The 5 MW HTS motor for warship test of electric propulsion was developed and tested. Also it was contracted between AMSC and United States of America navy to develop a 36.5 MW HTS motor in 3 years since March 3, 2003. This paper deals with the technical development tendency of HTS motors in foreign countries as well as in domestic, and it is focused on the application of HIS motors to the electrical propulsion system.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.322-324
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• 1994

The 2nd prototype LPM is designed as single side stator structure for improving the thrust force and acceleration time. Experimental results are shown that the static and dynamic characteristics are improved compared with the 1 st prototype. By the computer simulation, the permanent magnet design method is also clarified to desired thrust force. And microstep driver is adopted to the position controller to the designed LPM. The driver suppressed position errors within 1/10 pitch.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.312-313
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• 2011

Recently, many industrial electric vehicles have been developed using various ac-motor drive technologies including field oriented vector control. Generally, a magnetic encoder is installed to have resistance to vibration and dust, and it is cost-effective. However, it is difficult to get an accurate rotor speed for high performance of vector control, because a resolution of the magnetic encoder is low and its phase accuracy is poor. In order to overcome this hardware problem, this study proposes a speed measurement algorithm using moving window for low-resolution magnetic encoder. This algorithm is experimentally tested and successfully applied to traction application of industrial electric vehicle.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.316-317
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• 2011

Recently, many industrial electric vehicles have been developed using various ac-motor drive technologies including field oriented vector control. Generally, a magnetic encoder is installed to have resistance to vibration and dust, and it is cost-effective. However, it is difficult to get an accurate rotor speed for high performance of vector control, because a resolution of the magnetic encoder is low and its phase accuracy is poor. In order to overcome this hardware problem, this study proposes a speed measurement algorithm using moving window for low-resolution magnetic encoder. This algorithm is experimentally tested and successfully applied to traction application of industrial electric vehicle.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.10
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• pp.766-770
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• 2013

This paper tried to develop a BLDC electric motor securing the 800 W-level watertight structure for driving the outboard motor. For this purpose, this paper developed a high-efficient controller-integrating BLDC electric motor system for underwater propulsion and designed and developed a triple watertight structure. Besides, this study developed a outboard motor integrating motor, propeller and controller based on the production of a controller for BLDC motor which can the speed control by selecting low-voltage, high-current power element. The characteristics of developed outboard motor were 24 V input voltage, over 800 W motor output, and max. 3,000 rpm motor, and 84.9% motor efficiency, and the developed outboard motor could secure the watertight structure in 5 m in water depth.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.8
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• pp.71-78
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• 2012

Recently, it is increased to apply sensorless drive for BLDC (Brushless DC) motor to maximize operating efficiency and fuel efficiency to an electrical component of (H)EV. Especially, Electric vehicle component promotes a fuel efficiency enhancement by the carbon dioxide emissions regulation of a vehicle becoming the principal of the environmental pollution globally, the oil price hike that continued increasingly. We suggested the air compressor which applied BLDC motor for electric vehicle component and compared suggested BLDC motor with the conventional DC motor. The experimental results show that the driving efficiency was increased and was inproved compressive force by suggested BLDC motor.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1275-1277
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• 2001

Growing environmental and economic concerns have lead to recent efforts to produce more fuel efficient and lower emissions vehicles. Hybrid Electric Vehicles(ab. HEVs) are the most promising designs to reach these goals. In this paper, We present an of a Power Tra the Hybrid Electric Vehicle(at. PTHEV). We int a different concept of PTHEV than in the pr research of PTHEV. This PTHEV includes benefits of serial(Minimum emission and Max efficiency) and parallel(Maximum Power efficiency by direct drive engine) PTHEV. Also mechanism can avoid driving the engine in the speed regions.