• Proceedings of the KIEE Conference
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• 2004.10a
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• pp.24-26
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• 2004

The PM(Permanent Magnet) stepping Motor has been used widely to a variety of industries because of the open-loop control characteristic, a relatively large frequency range of velocity control and non-accumulated error of the step angle. Moreover, It has been gradually applied to office automation, machine intelligence, digital appliance, and automobile parts. This paper presents the optimal design results by use of the experimental method. The design variables of the PM stepping motor are shape of the claw-pole, material of core, and air-gap. As a result, a superior claw-pole PM stepping motor for OA machinery was developed.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.12
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• pp.1230-1241
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• 1991

Asymmetrical pulse width modulated(APWM) control technique for AC chopper is proposed which can improve the input power factor. The ideal switching function for the proposed technique is derived and its optimal slope to maintain the input power factor to unity is calculated. By digital simulation several characteristics are investigated theoretically and then compared with those of the conventional PWM and the phase angle control technique. In order to maintain the input power factor to unity the optimal slope and the average value of the ideal switching function are calculated. The experimental results show a good agreement with the calculated ones, which proves the feasibility of the proposed technique.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.28 no.1
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• pp.39-44
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• 1992

Analog PID controllers have been designed to make good use of position control in industries. Recently, the importance of digital position control is emphasized for the requirements of controller which are not only to control the objects but to include various aspects such as easiness of design and implementation, simple exchange of control program and convenient communications of data between various controllers and a host computer. This study proposes a combined control method which is mixed the vaiable structure control (VSC) with the PI control for minimum time position control of DC servo motor by microcomputer. The results of test by this method show offset-free and minimum time optimal position control which is not affected by the disturbance and the system parameter variations. The validity of the proposed method comparing with the conventional PID control is proved by the response experiments.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.1
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• pp.81-90
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• 2002

This paper presents an Implementation of digital high-performance position sensorless control system of Reluctance Synchronous Motor(RSM) drives with Direct Torque Control(DTC). The system consists of stator flux observer, speed and torque estimator, two digital hysteresis controllers, an optimal switching look-up table, Insulated Gate Bipolar Transistor(IGBT) voltage source inverter, and TMS320C31 DSP board. The stator flux observer Is based on the combined voltage and current model with stator flux feedback adaptive control of which inputs are current and voltage sensed on motor terminal for wide speed range. In order to prove the suggested sensorless control algorithm for industrial field application, we have some simulation and actual experiment at low and high speed range. The developed high-performance speed control by fully digital system are shown a good response characteristic of control results and high performance features using 1.0[kW] RSM having 2.57 reluctance ratio of $L_d/L_q$.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.1
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• pp.47-52
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• 2005

This paper presents dimming control system for automotive 35W metal halide discharge(MHD) lamp electronic ballast. HID lamp demands a highly efficient ballast and very complex control circuitry that can control complex transient state in applying to automotive. Therefore, in this paper, a microcontroller-based digital control method for the HID lamp ballast is presented for optimal control that can adapt complex transient state, steady state and various environments. In developed dimming system, the system is designed to control the lamp output voltage step by step(continuous) using microcontroller according to CdS sensor. Therefore the designed dimming control system give good driving condition to diver and realize the power control effectively. The results of the proposed system is verified through various experiment results.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.1
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• pp.111-121
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• 1995

A fuzzy control algorithm of bell-type membership functions and 9 rules is constructed for narrow range level control of steam generators in nuclear power plants. It is implemented at a field digital distributed controller, a Westinghouse-made controller called Westinghouse Distributed Processing Family(WDPF). Performance for level control of the developed fuzzy controller is compared with that of conventional controller, both at the field controller. For these comparisons, both the fuzzy control algorithm and the conventional PI control algorithm were carefully tuned. Also the sampling time for optimal performance was investigated. The results show that the fuzzy control algorithm is not only better in performance than the conventional algorithm but also much easier to be tuned by operators in the field.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.2
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• pp.144-155
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• 1992

A design of a highly stable current-controlled power supply combining the phase-controlled rectifier (PCR), passive filter and active filter is investigated. A digital phase-looked voltage control (PLVC) with a capability of compensating the thyristor firing angles under unvalanced power source is proposed` otherwise the PCR output voltage has low-order subharmonics whose suppression requires a bulky passive filter. The digital PLVC has a fast dynamic characteristics as an inner control loop of the PCR. To suppress further the output ripple, an active filter using a transformer is introduced and its design is described through the frequency domain analysis. An optimal integral, proportional and measurable variable feedback (IPM) controller is designed using the time-weighted performance index based on the time domain analysis. The design method based on the time-weighted performance index gives better response characteristics than that based on the conventional performance index. It is also shown via experimental results that the proposed scheme gives better response characteristics than that based on the conventional performance index. It is also shown via experimental results that the proposed scheme gives good dynamic and static performances.

• Journal of the East Asian Society of Dietary Life
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• v.20 no.2
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• pp.291-298
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• 2010

The influence of cabbage powder on sensory acceptance and physical functions of Jeungpyun, were assessed. As fermentation continued, pH dropped and evolved carbon dioxide significantly increased. Moisture content of cabbage powder-amended Jeungpyun ranged from 51.1~55.5%, and were lower than those of control samples. Jeungpyun prepared with 8~10% cabbage powder displayed significantly lower specific volumes. As the level of cabbage powder increased, the L-value was reduced, while the a- and b-values increased. Hardness was not significantly different among the control, 2%, 4% and 6% samples. Chewiness tended to increased in proportion to the level of cabbage powder. Sensory scores were lowest for Jeungpyun prepared with 8~10% cabbage powder. The results indicate that addition of 4~6% cabbage powder to Jeungpyun produces the optimal product.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.830-837
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• 2011

A turbine control system which has been operated for years in a nuclear power plant was retrofitted with a newly developed digital control system. After completion of the retrofit, turbine valve tests were performed to ensure the integrity of each valve's control function. The sequence of each valve test is composed of a closing process and a reopening process. To minimize megawatt variation which normally occurs during the test sequence, we employed a kind of compensator algorithm in the new digital control system which also have been used in the old system. There were difficulties finding optimal parameter settings for our new compensator algorithm because the power plant didn't allow us to perform necessary tuning procedures while the turbine is on load operation. Therefore an alternative measure for the compensator tuning which is independent of the turbine actual operation had to be implemented. So, a process model for the test was required to overcome this situation. We analyzed the operation data of the test and implemented the process model by use of input and output variable relations. Also we verified the process model by use of another condition's operating data. The result shows that the output of model is similar to the actual operation data.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.615-619
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• 2000

This paper presents an implementation of digital motion control system of Surface Permanent-Magnet Synchronous Motor(SPMSM) vector drives with a direct torque control(DTC) using the 16bit DSP TMS320F240 The DSP controller enable enhanced real time algorithm and cost-effective design of intelligent control for motors which can be yield enhanced operation fewer system components lower system cost increased efficiency and high performance The system presented are stator flux and torque observer of stator flux feedback model that inputs are current and voltage sensing of motor terminal and angle for a low speed operating area two hysteresis band controllers an optimal switching look-up table and IGBT voltage source inverter by using fully integrated control software. The developed control system are shown a good motion control response characteristic results and high performance features using 1.0Kw purposed servo drive SPMSM.