• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.277-280
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• 2001

This paper presents a speed sensorless implementation of digital speed control system of Surface Permanent-Magnet Synchronous Motor(SPMSM) drives with a direct torque control(DTC). The system presented are stator flux and torque observer of stator flux feedback control model that inputs are current and voltage sensing of motor terminal with estimated rotor angle for a low speed operating area, two hysteresis band controllers, an optimal switching look-up table, rotor speed estimator, and IGBT voltage source inverter by using fully integrated control software. The developed speed sensorless control system are shown a good motion control response characteristic results and high performance features using 1.0Kw purposed servo drive SPMSM.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 전력전자학술대회 논문집
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• pp.397-400
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• 2001

This paper presents a implementation of digital sensorless position control system of surface permanent-magnet synchronous motor (SPMSM) drive with a direct torque control (DTC). The system are stator flux and torque observer of stator flux feedback control model that inputs are current and voltage sensing of motor terminal with estimated rotor angle for a low speed operating area, two hysteresis band controllers, an optimal switching look-up table, rotor speed estimator, and IGBT voltage source inverter by using fully integrated control software. The developed sensorless control system are shown a good motion control response characteristic results and high performance features using 1.0 (kW) purposed servo drive SPMSM.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 학술대회 논문집 전문대학교육위원
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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.

• 전력전자학회논문지
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• 제7권5호
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• pp.427-436
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• 2002

본 논문은 직접토크제어(Direct torque control, DTC)를 사용한 릴럭턴스 동기전동기(Reluctance synchronous motor, RSM)의 위치센서 없는 모션제어 시스템을 제안한다. 고성능 효율제어를 수행하는데 있어서 DTC를 이용한 릴럭턴스 전동기 드라이브는 고정자 쇄교자속의 포화와 부하전류에 따라 비선형적으로 변하는 인덕턴스로 인해 여러 가지 문제점들이 발생한다. 이러한 이유로 본 논문에서는 정확한 고정자 쇄교자속과 토크를 계산하기 위해서 자속관측기의 $L_d\;와\; L_q$값을 회전자 위치와 고정자 전류에 대해 보상하였으며, 빠른 토크 응답특성과 최적 효율특성을 얻기 위해서 기준자속을 부하에 따라 계산하였다. 제안된 알고리즘의 정당성을 확인하기 위해서 1.0[kW] 릴럭턴스 동기 전동기를 사용하여 $\pm$20[rpm]과 $\pm$1500[rpm]에서 실험을 수행하였고, 실험을 수행한 결과 저속영역과 고속영역 모두 우수한 동특성과 향상된 효율을 얻을 수 있었다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 추계학술대회 논문집
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• pp.23-26
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• 2001

This paper presents a digital motion control system for Reluctance Synchronous Motor (RSM) drives with direct torque control (DTC). The system consists of stator flux observer, torque estimator: two hysteresis band controllers, an optimal switching look-up table, IGBT voltage source inverter(VSI), 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 of which inputs are current, voltage and actual rotor angle for wide speed range. In order to prove the suggested motion control algorithm, There are some simulation and testing at actual experimental system. The developed digitally high-performance motion control system are shown a good motion control response characteristic results and high performance features using 1.0Kw RSM.

• Journal of Power Electronics
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• 제17권2호
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• pp.368-379
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• 2017

In this paper, a direct torque control algorithm with novel duty cycle-based modulation is proposed for permanent magnet synchronous motor drives fed by neutral-point clamped three-level inverters. Compared with the standard DTC, the proposed algorithm can suppress steady-state torque ripples as well as ensure neutral-point potential balance and smooth vector switching. A unified torque/flux evaluation table with multiple voltage vectors and precise control levels is established and used in this method. This table can be used to evaluate the effects of duty-cycle vectors on torque and flux directly, and the elements of the table are independent of the motor parameters. Consequently, a high number of appropriate voltage vectors and their corresponding duty cycles can be selected as candidate vectors to reduce torque ripples by looking up the table. Furthermore, small vectors are incorporated into the table to ensure the neutral-point potential balance with the numerous candidate vectors. The feasibility and effectiveness of the proposed algorithm are verified by both simulations and experiments.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권1호
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• pp.9-15
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• 2006

The conventional hysterysis band DTC(Direct Torque Control) strategy have relatively high torque ripple at low speed and variable switching frequency according to motor speed even though it provides a fast torque response with very simple scheme consisted with only two hysteresis band comparators and a switching table for torque and flux control. In this paper, author proposed a new DTC scheme based on the torque slope and reference voltage control. The new scheme can maintain the minimized torque ripple and constant switching frequency. Experimental tests carried out with an 1.5kW induction motor drive system show improved dynamic characteristics and prove the feasibility of proposed strategy.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.415-419
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• 2003

This paper focuses on a simple technique to reduced torque ripple in the direct torque control inverter for PMSM drive. It is actually impossible to raise the inverter switching frequency in the conventional system, although the hysterisis bandwidths for the stator flux and torque control are sufficiently diminished, because of the sampling Interval and the delay in estimating the flux and the torque In order to overcome the problem, the proposed method introduces a dithering technique into the conventional system by superposing triangular waves with high frequency and minute amplitude on the torque error. And the programable 3- stage lowpass filter is added instead of pure Integrator. Simulation results prove the feasibility of proposed strategy compared with conventional method.

• Journal of Power Electronics
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• 제9권3호
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• pp.438-446
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• 2009

The performance of direct torque controlled (DTC) interior permanent magnet (IPM) machines is poor at low speeds due to a few reasons, namely limited accuracy of stator voltage acquisition and the presence of offset and drift components in the acquired signals. Due to factors such as forward voltage drop across switching devices in the three phase inverter and dead-time of the devices, the voltage across the machine terminals differ from the reference voltage vector used to estimate stator flux and electromagnetic torque. This can lead to instability of the IPM drive during low speed operation. Compensation schemes for forward voltage drops and dead-time are proposed and implemented in real-time control, resulting in improved performance of the space vector modulated DTC IPM drive, especially at low speeds. No additional hardware is required for these compensators.

• Journal of Electrical Engineering and Technology
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• 제4권1호
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• pp.66-78
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• 2009

This paper introduces the design of a fuzzy logic controller in conjunction with direct torque control strategy for a Permanent Magnet synchronous machine. A stator flux angle mapping technique is proposed to reduce significantly the size of the rule base to a great extent so that the fuzzy reasoning speed increases. Also, a fuzzy resistance estimator is developed to estimate the change in the stator resistance. The change in the steady state value of stator current for a constant torque and flux reference is used to change the value of stator resistance used by the controller to match the machine resistance.