• 전력전자학회논문지
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• 제7권2호
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• pp.137-148
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• 2002

직접토크제어 기법은 벡터제어계 설계 및 운전시 요구되는 복잡한 좌표변환과 전류제어루프가 불필요하며, 빠른 토크응답을 얻을 수 있기 때문에 벡터제어 기법에 버금가는 유도전동기의 고성능 제어기법으로 인정되고 있다. 본 논문에서는 직접토크제어 기법 적용시 중요한 어려움의 하나로 지적되고 있는 저속영역에서의 자속저하 및 이로 인한 전류고조파의 증가 문제를 해결하기 위한 대책으로서 퍼지 가변 스위칭섹터 기법과 이 기법의 실시간 적용을 위한 실현방법을 제안하였다. 제안된 스위칭섹터 기법을 포함한 유도전동기 제어시스템의 실험적 성능을 고찰하기 위하여 DSP를 이용한 제어보드를 제작하였다. 시뮬레이션과 실험 결과는 제안된 퍼지 가변스위칭 섹터 기법을 도입함으로서 유도전동기 드라이브의 성능이 현저히 개선됨을 보여준다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.181-185
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• 2000

To get high efficiency in variable speed control of induction motor it is required that the vector control should be separated from flux components current and torque component current. In this paper the vector control is modeled by the estimation of the stator flex. Representing induction motor speed controller as a digital system with he use of he 32bit DSP improves the motor control performance The IGBT is used as the switching device and the validity of the proposed vector control is proved through voltage current wave and the characteristics of the velocity response as the drive circuit being simplified

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.1206-1208
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• 2001

Direct torque control(DTC) of AC motor has the fast torque and flux dynamic responses even though it has very simple scheme to implement. DTC is also very simple in its implementation because it needs only two hysteresis comparators and switching vector table for both flux and torque control. The amplitude of hysteresis band greatly influences on the drive performance such as flux and torque ripple, switching frequency and current harmonics. Therefore, authors analysis flux and torque hysteresis bands is suggested considering switching frequency and harmonic distortion of currents.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 B
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• pp.336-338
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• 2000

Recently many studies have been performed for variable speed control of induction motor. Direct Torque Control(DTC) is emerging technique for variable speed control of PWM inverter driven induction motor. DTC allows the direct control of stator flux and instantaneous torque through simple algorithm. In this paper ASIC design technique using VHDL is applied to DTC based speed control of induction motor. ASIC for DTC based speed control is designed through the description of coordinate transformation, speed controller stator flux and torque estimator, stator flux and torque controller, stator flux position detector. FSM(Finite State Machine) and inverter voltage switching vector. Finally the above system has been implemented on the FPGA (XC4052XL-PG411). Simulation and experiment has been performed to verify the performance of the designed ASTC.

• Journal of Power Electronics
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• 제16권3호
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• pp.994-1003
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• 2016

Two major obstacles in the utilization of electrical vehicles are their price and range. The collaboration of direct torque control (DTC) with induction motor (IM) is preferred for its low cost, easy implementation, and parameter independency. However, in terms of edges, the method has drawbacks, such as variable switching frequency and undesired current harmonic distortion. These drawbacks result in acoustic noise, reduced efficiency, and electromagnetic interference. A feed-forward approach for stator-flux-oriented DTC with space vector pulse-width modulation is presented in in this paper. The outcome of the proposed method is low current harmonic distortion with fixed switching frequency while preserving the torque performance and simple application feature of basic DTC. The method is applicable to existing and forthcoming IM drive systems via software adaptation. The validity of the proposed method is confirmed by simulation and experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.1135-1137
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• 2003

The conventional DTC strategy provides a fast torque response even though it has very simple scheme consisted with only two hysteresis band comparators and a switching table for torque and flux control. Drawbacks of the conventional BTC are relatively high torque ripple at low speed and variation of the switching frequency according to motor speed. In this paper, the new direct torque control(BTC) schemes are proposed. Those schemes are based on the torque slope and and flux to reduce the torque ripple.

• Journal of Power Electronics
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• 제9권5호
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• pp.679-690
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• 2009

The paper presents a new photovoltaic inverter for stand-alone induction motor application. The proposed system is composed of two stages. First stage is for the photovoltaic dc power feeding and second stage is dedicated to the motor-inverter subsystem and control technique. A direct torque control (DTC) with a novel switching strategy for motor torque ripple minimization is introduced. The novel DTC strategy is based on selecting a suitable voltage vector group for motor torque ripple minimization. A three-level voltage source inverter (VSI) is used instead of a two level inverter because the first has more available vectors and lower ripples in the output current and flux than the second, thus it has lower torque ripples. The photovoltaic array and battery bank are sized and the configuration is indicated based on sun-hour methodology. Simulation results show a comparison between three systems; two level VSI with conventional DTC strategy, three level VSI with conventional DTC, and the proposed system that has a novel DTC switching strategy applied to three level VSI. The results show that the proposed system has lower ripples in the current, flux and torque of the motor.

• International Journal of Control, Automation, and Systems
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• 제5권6호
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• pp.652-662
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• 2007

This paper presents a new and simple method for sensorless operation of matrix converter drives using a constant air-gap flux and the imaginary power flowing to the motor. To improve low-speed sensorless performance, the non-linearities of a matrix converter drive such as commutation delays, turn-on and turn-off times of switching devices, and on-state switching device voltage drop are modeled using PQR transformation and compensated using a reference current control scheme. The proposed compensation method is applied for high performance induction motor drives using a 3 kW matrix converter system. Experimental results are shown to illustrate the feasibility of the proposed strategy.

• Journal of Magnetics
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• 제15권2호
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• pp.74-77
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• 2010

This paper deals with optimum design criteria for maximum torque density & minimum torque ripple of a Flux Switching Motor (FSM) using response surface methodology (RSM) & finite element method (FEM). The focus of this paper is to find a design solution through the comparison of torque density and torque ripple which vary with rotor shape. And then, a central composite design (CCD) mixed resolution was introduced and analysis of variance (ANOVA) was conducted to determine the significance of the fitted regression model. The proposed procedure allows one to define the rotor dimensions, starting from an existing motor or a preliminary design.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.355-359
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• 2001

This paper presents an implementation of digital control system of speed sensorless for Reluctance Synchronous Motor (RSM) drives with DTC. The control system consists of stator flux observer, rotor position/speed/torque estimator, two hysteresis band controllers, an optimal switching look-up table, IGBT voltage source inverter, and TMS320C31 DSP controller by using fully integrated control software. The stator flux observer is based on the combined voltage and current model with stator flux feedback adaptive control that inputs are current and voltage sensing of motor terminal with estimated rotor angle for wide speed range. The rotor position is estimated by observed stator flux-linkage space vector. The estimated rotor speed is determined by differentiation of the rotor position used only in the current model part of the flux observer for a low speed operating area. It does not require the knowledge of any motor parameters, nor particular care for motor starting, In order to prove the suggested control algorithm, we have a simulation and testing at actual experimental system. The developed sensorless control system is shown a good speed control response characteristic results and high performance features in 50/1000 rpm with 1.0Kw RSM having 2.57 ratio of d/q reluctance.