• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.05a
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• pp.39-44
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• 1999

It can be acquired the high effective productivity through of high speed, precision of machine tools, and then, machine tools will be got a competitive power. Industrially advanced countries already developed that the high speed feed is 60m/min using the high speed ball screw. Also, a lot of problems have happened the feed drive system. It is necessary to study about the character of positioning accuracy, heat generation and high speed control for feed drive system of high speed. In this study, we make use of the feed drive system with a ball screw of large-scale-lead. We'll develop the feed drive system at the speed of 60m/min. Using the design of the mechanical element and the high speed control, the basic design concept can be established. After manufacturing one-shaft feed drive system and conducting the performance test, it'll be analyzed properties of the high speed feed drive system.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.437-445
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• 2002

The development of railway vehicle and bogie involves the proper selection of design parameters not only to achieve high speed of the train but also to reduce the vibration. In this study, an analytical model of a high speed freight car is developed to find the critical speed. The high speed freight car can generate the snake motion of the lateral, rolling and yawing motion of the car body and the bogie. The numerical analysis for the equation motions with 17 degrees of freedom showed the running stability and the critical speed due to the snake motion. Also the vibration modes of the high speed freight car was calculated using ADAMS RAIL software, which showed that the critical speed have the yawing modes of the car body and the bogie.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.2
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• pp.185-192
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• 1996

This paper presents a design of vertical axis Darrieus wind turbine combine with Savonius for wind-power generating system to be adapted for variable wind speed. The wind turbine consists of two troposkien- and four Savonius-blades. Darrieus turbine is designed with diameter 9.4[m], chord length 380[mm], tip speed ratio 5. Savonius turbine is designed with diameter 1.8[m], height 2[m], tip speed ratio 0.95. The design of turbine is laid for the main data of rated wind speed 10[m/s], turbine speed 101.4[rpm]. The generating power is estimated to maximum power 20[kW], and this is converted to commercial power line by means of three phase synchronous generator-inverter system. Generating system is designed for operation on VSVF(variable speed variable frequency) condition and constant voltage system.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.12
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• pp.676-681
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• 2002

This paper presents the implementation and experimental investigation of sensorless speed control for a variable-speed PMSM(Permanent Magnet Synchronous Motor) in super-high speed compressor operation. The proposed control scheme consists of two different sensorless algorithms to guarantee the reliable starting operation in low speed region and full torque characteristics using the vector control in high speed region. An automatic switching technique between two control modes is proposed to minimize the speed and torque pulsation during the switching instant of control mode. A testing system of 3.3㎾ PMSM has been built and 90% load test results at 7000r/min are presented to examine the feasibility of proposed sensorless control scheme.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.2
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• pp.330-337
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• 2011

This paper presents a new fuzzy speed controller based on a fuzzy angular acceleration observer to realize a robust speed control of permanent magnet synchronous motors(PMSM). The proposed speed controller needs the information of the angular acceleration, thus the first-order fuzzy acceleration observer is designed. The LMI existence condition is given for the proposed fuzzy speed controller, and the gain matrices of the controller are calculated. It is verified that the augmented control system consisting of the fuzzy speed controller and the fuzzy acceleration observer is mathematically stable. To validate the effectiveness of the proposed acceleration observer-based fuzzy speed controller, the simulation and experimental results are shown under motor parameter variations. It is definitely proven that the proposed control scheme can precisely track the speed of a permanent magnet synchronous motor.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.8
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• pp.48-59
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• 2011

This paper presents a new gain scheduling speed controller of permanent magnet synchronous generators(PMSG) for MW-class direct-driven wind turbine systems. The proposed gain scheduling speed controller performs the speed tracking at more than one operating point, and the first-order torque observer estimates the turbine torque which is needed to precisely control the speed of PMSG. The proposed speed controller verifies that the PMSG can successfully follow the reference speed which is determined via the maximum power point tracking(MPPT) control and pitch control under turbulent wind conditions. The proposed speed control algorithm is simulated using Simulink and its performance is confirmed through comparison with the results by PI control method.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.11
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• pp.763-770
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• 2000

The speed and position information of the rotor are required in the speed control of SRM(Switched Reluctance Motors). This information is generally provided by shaft encoder or resolver. It is weak in the dusty, high temperature, and EMI environment. Consequntly, much attention has been given to SRM control for eliminationating the position and speed sensors. In this paper, a new estimation algorithm for the rotor position and speed for SRM drives is described. The algorithm is implemented by the sliding mode observer. The stability and robustness of the sliding observer for the parameter variations of the SRM are proved by variable structure control theory. Speed control of the SRM is accomplished by the estimated speed and position. Experiment results verify that the mode observer is able to estimate the speed and position well.

• Proceedings of the KIPE Conference
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• 2002.11a
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• pp.3-6
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• 2002

In a conventional speed sensorless stator flux-oriented(SFO) induction motor drive system, when the estimated speed is transformed into the sample-data model using the first-forward difference approximation, the sampled data model has a modeling error which, in turn, produces an error in the rotor speed estimation. The error included in the estimated speed is removed by the use of a low pass filter (LPF). As the result, the delay of the estimated speed occurs in transients by the use of the LPF This paper investigates the problem of a conventional speed sensorless SFO system due to the delay of estimated speed in the filed weakening region. In addition, this paper proposes a method to estimate exactly speed by using Luenberger observer, The proposed method is verified by experiment with a 5-hp induction motor drive.

• International Journal of Automotive Technology
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• v.6 no.5
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• pp.475-481
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• 2005

This paper deals with the algorithm of estimating the longitudinal speed of a braking vehicle using measurements from an accelerometer and a standard wheel speed sensor. We evolve speed estimation algorithms of increasing complexity and accuracy on the basis of experimental tests. A final speed estimation algorithm based on a Kalman filtering is developed to reduce measurement noise of the wheel speed sensor, error of the tire radius, and accelerometer bias. This developed algorithm can give peak errors of less than 3 percent even when the accelerometer signal is significantly biased.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.750-752
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• 2010

MANET has some interest as a wireless mobile network supporting node mobility and having no additional infrastructure. Speed of mobile node on MANET is various from just slow speed of human's walk to vehicle's moving speed. In this study, VoIP performance of MANET is evaluated in the view of speed of mobile node. VoIP performance is studied on walking speed, vehicle speed and higher speed on MANET. PDR(Packet Delivery Ratio), MOS(Mean Opinion Score) are used as performance parameters.