• Title/Summary/Keyword: Direct Current Motor

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An Induction Motor Control System with Direct Torque and Flux Control (직접 토크 및 자속제어에 의한 유도전동기 제어시스템)

  • Kim, Min-Huei;Kim, Nam-Hun;Kim, Min-Ho
    • Proceedings of the KIEE Conference
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    • 2000.07e
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    • pp.79-84
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    • 2000
  • This paper presents an implementation of digital position control system for an induction motor vector drives by a direct torque control(DTC) using the 16bit DSP TMS320 F240. The DSP controller enable enhanced real time algorithm and cost-effective design of intelligent controller 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 using current model that inputs are current sensing of motor terminal and rotor angle for a low speed operating area, two hysteresis controller, optimal switching look-up table, and IGBT voltage source inverter by fully integrated control software. The developed control system are shown a good motion control response characteristic results and high performance features using 2.2Kw general purposed induction motor.

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Changes in Sensory Function After Transcranial Direct Current Stimulation on Primary Motor Cortex Area

  • Min, Dong-Ki
    • Physical Therapy Korea
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    • v.21 no.4
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    • pp.1-8
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    • 2014
  • Transcranial direct current stimulation (tDCS) is a neuromodulatory technique that delivers low-intensity direct current to cortical areas, thereby facilitating or inhibiting spontaneous neuronal activity. This study was designed to investigate changes in various sensory functions after tDCS. We conducted a single-center, single-blinded, randomized trial to determine the effect of a single session of tDCS with the current perception threshold (CPT) in 50 healthy volunteers. Nerve conduction studies were performed in relation to the median sensory and motor nerves on the dominant hand to discriminate peripheral nerve lesions. The subjects received anodal tDCS with 1 mA for 15 minutes under two different conditions, with 25 subjects in each groups: the conditions were as follows tDCS on the primary motor cortex (M1) and sham tDCS on M1. We recorded the parameters of the CPT a with Neurometer$^{(R)}$ at frequencies of 2000, 250, and 5 Hz in the dominant index finger to assess the tactile sense, fast pain and slow pain, respectively. In the test to measure CPT values of the M1 in the tDCS group, the values of the distal part of the distal interphalangeal joint of the second finger statistically increased in all of 2000 Hz (p=.000), 250 Hz (p=.002), and 5 Hz (p=.008). However, the values of the sham tDCS group decreased in all of 2000 Hz (p=.285), 250 Hz (p=.552), and 5 Hz (p=.062), and were not statistically significant. These results show that M1 anodal tDCS can modulate sensory perception and pain thresholds in healthy adult volunteers. The study suggests that tDCS may be a useful strategy for treating central neurogenic pain in rehabilitation medicine.

Modified Direct Torque Control System of Five Phase Induction Motor

  • Kim, Nam-Hun;Kim, Min-Huei
    • Journal of Electrical Engineering and Technology
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    • v.4 no.2
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    • pp.266-271
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    • 2009
  • In this paper, improved direct torque control(DTC) of five-phase induction motor(IM) is proposed. Due to the additional degrees of freedom, five-phase IM drives present unique characteristics. One of them is the ability of enhancing the torque producing capability of the motor. Also five-phase motor drives possess many others advantage compared with the traditional three-phase motor drives. Such as, reducing the amplitude and increasing of frequency of torque pulsation, reducing amplitude of current per phase without increasing the voltage per phase and increasing the reliability. The direct torque control method is advantageous when it is applied to the five-phase IM. Because the five-phase inverter provides 32 space vectors in comparison to 8 space voltage vectors by the three-phase inverter. The 32 space voltage vectors are divided into three groups according to their magnitudes. The characteristics and dynamic performance of traditional five-phase DTC are analyzed and new DTC for five-phase IM is proposed. Therefore, a more precise flux and torque control algorithm for the five-phase IM drives can be suggested and explained. For presenting the superior performance of the pro-posed direct torque control, experimental results is presented using a 32 bit fixed point TMS320F2812 digital signal processor

An Optimal Efficiency Control of Reluctance Synchronous Motor using Direct Torque Control (직접 토크 제어를 이용한 리럭턴스 동기 전동기의 최대 효율제어)

  • Park Hong-il;Kim Nam-Hun;Choi Kyeong-Ho;Kim Dong-Hee;Kim Min-Huei
    • Proceedings of the KIPE Conference
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    • 2002.07a
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    • pp.431-434
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    • 2002
  • This paper presents an implementation of direct torque control(DTC) of Reluctance Synchronous Motor(RSM) with an efficiency optimization using the 32bit DSP TMS320C31. The influence of iron loss can not neglected as high speed and precision torque control of RSM, so the optimal current ration between torque current and exiting current analytically derived to drive RSM at maximum efficiency For RSM, torque dynamics can be maintained even with controlling the flux level because the generated torque is direct]y proportional to the stator current. The experimental results for an RSM are presented to validate the applicability of the proposed method. The developed control system is shown high efficiency features with 1.0Kw RSM having 2.57 ratio of d/q reluctance.

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Speed Characteristics of Direct Current Shunt Motors (직류 분권전동기의 속도 특성)

  • Shin, Myoung-Ho
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.26 no.3
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    • pp.69-72
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    • 2012
  • It is well known that speed of a direct current shunt motor is inverse proportional to flux. This paper presents speed expression to show that speed is not inverse proportional to flux. The presented speed vs. flux curves are verified by experimental result that shows the need of the revision of speed vs. flux curves shown in conventional text books.

Torque Ripple Reduction Method With Enhanced Efficiency of Multi-phase BLDC Motor Drive Systems Under Open Fault Conditions (다상 BLDC 모터 드라이브 시스템의 개방 고장 시 효율 향상이 고려된 토크 리플 저감 대책)

  • Kim, Tae-Yun;Suh, Yong-Sug;Park, Hyeon-Cheol
    • The Transactions of the Korean Institute of Power Electronics
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    • v.27 no.1
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    • pp.33-39
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    • 2022
  • A multi-phase brushless direct current (BLDC) motor is widely used in large-capacity electric propulsion systems such as submarines and electric ships. In particular, in the field of military submarines, the polyphaser motor must suppress torque ripple in various failure situations to reduce noise and ensure stable operation for a long time. In this paper, we propose a polyphaser current control method that can improve efficiency and reduce torque ripple by minimizing the increase in stator winding loss at maximum output torque by controlling the phase angle and amplitude of the steady-state current during open circuit failure of the stator winding. The proposed control method controls the magnitude and phase angle of the healthy phase current, excluding the faulty phase, to compensate for the torque ripple that occurs in the case of a phase open failure of the motor. The magnitude and phase angle of the controlled steady-state current are calculated for each phase so that copper loss increase is minimized. The proposed control method was verified using hardware-in-the-loop simulation (HILS) of a 12-phase BLDC motor. HILS verification confirmed that the increase in the loss of the stator winding and the magnitude of the torque ripple decreased compared with the open phase fault of the motor.

Characteristics Analysis for Reactor Starting Method of 3-Phase Induction Motor Considering Saturation (포화성분을 고려한 3상 유도전동기 리액터 기동 특성 분석)

  • Kim, Jong-Gyeum
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.26 no.8
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    • pp.65-70
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    • 2012
  • Induction motor is the most widely used to obtain the driving force in the industrial site. Induction motor generates a high current at startup. Most of starting currents are often more than five times of rated current. This high starting current can cause problems such as the voltage drop in the system. In order to solve these problems, if the motor capacity is large, generally we use reactor starting method rather than direct on line starting method. When a high startup current passes through reactor, reactor can serve as a nonlinear elements. In this study, we analyzed that the current, torque and power of the induction motor are different from the change of linear and nonlinear components of the reactor magnetic field.

Intelligent Control for Torque Ripple Minimization in Combined Vector and Direct Controls for High Performance of IM Drive

  • Boulghasoul, Zakaria;Elbacha, Abdelhadi;Elwarraki, Elmostafa
    • Journal of Electrical Engineering and Technology
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    • v.7 no.4
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    • pp.546-557
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    • 2012
  • In Conventional Combined Vector and Direct Controls (VC-DTC) of induction motor, stator current is very rich in harmonic components. It leads to high torque ripple of induction motor in high and low speed region. To solve this problem, a control method based on the concept of fuzzy logic approach is used. The control scheme proposed uses stator current error as variable. Through the fuzzy logic controller rules, the choice of voltage space vector is optimized and then torque and speed are controlled successfully with a less ripple level in torque response, which improve the system's performance. Simulation results trough MATLAB/SIMULINK${(R)}$ software gave results that justify the claims.

A Study on the Sensorless Speed Control of Induction Motor using Direct Torque Control (직접토크 제어를 이용한 유도전동기의 센서리스 속도제어에 관한 연구)

  • Yoon, Kyoung-Kuk;Oh, Sae-Gin;Kim, Jong-Su;Kim, Yoon-Sik;Lee, Sung-Gun;Kim, Sung-Hwan
    • Journal of Advanced Marine Engineering and Technology
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    • v.33 no.8
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    • pp.1261-1267
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    • 2009
  • The Direct Torque Control[DTC] controls torque and flux by restricting the flux and torque errors within respective hysteresis bands, and motor torque and flux are controlled by the stator voltage space vector using optimum inverter switching table. And the Current Error Compensation method is on the basis of compensating current difference between the induction motor and its numerical model, in which the identical stator voltage is supplied for both the actual motor and the model so that the gaps between stator currents of the two can be forced to decay to zero as time proceeds. Consequently, the rotor speed approaches to the model speed, namely, setting value and the system can control motor speed precisely. This paper proposes a new sensorless speed control of induction motor using DTC and Current Error Compensation, which requires neither shaft encoder, speed estimator nor PI controllers. And through computer simulation, confirm effectiveness of proposed method.

Parameters Estimation Characteristics of Five-Phase Squirrel-Cage Induction Motor within Over Current Load (과전류 부하에서 5상 농형 유도전동기의 정수 특성)

  • Kim, Min-Huei
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.7
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    • pp.38-46
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    • 2015
  • This paper propose a variable parameter estimations for variable over current load of five-phase squirrel-cage induction motor(IM) to servo control system. In order to high performance control of AC motor using a field oriented control(FOC) and direct torque control(DTC) algorithm, there are required precise motor parameters for slip calculation, flux observer, controller gain, torque command of current components, rotor position, speed estimation, and so on. We are suggest a analyzed estimation results of the motor parameters that developing five-phase squirrel-cage IM have a stator of concentrated winding for experimental within variable over current load at rated input frequency. There are results of stator winding measurement, no-load test, locked-rotor test, variable over current load test, and estimated parameters of equivalent circuits using manufactured experimental apparatus by IEEE Standard Test Procedure for Polyphase Induction Motors and Generators 112-2004.