• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.4
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• pp.305-315
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• 2022

In this paper, phase current ripples and torque ripples of six-phase PM synchronous motor controlled by interleaved PWM are analyzed. The cause of the increase of phase current ripple in the interleaved PWM was mathematically analyzed based on the mutual inductance of stator windings and effective voltage vector. Simulation and experiment verified that the DQ current ripple and torque ripple can be reduced by interleaved PWM control. The FFT analysis of torque waveform confirmed that the magnitude of harmonic torque corresponding to double the PWM frequency was reduced.

• Proceedings of the KIEE Conference
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• 2005.10a
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• pp.202-205
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• 2005

본 연구는 스파이랄 벡터에 기초한 유도전동기 모델의 해석을 나타내고 이 해에 기초한 자계가속법(Field Acceleration Method)에 의해 순시 토크 제어와 회생전력 해석을 나타내었다. 전압지령형의 PWM제어에서 전압형 인버터에 의해 전동기가 동작할 때 전력회생이 수식으로 해석 되었다. 전압지령형의 전압 PWM 인버터에 의한 유도 전동기의 속도 서보시스템을 설계하고 이 속도제어 시스템을 이용해 가감속시의 소비(회생)전력을 측정하여 실제 시스템에서 전력 절약정도를 검토하였다. FAM법에 의한 실험을 행하고 유효성을 확인하였다. 고정자 저항의 측정오차나 변동은 여자전압에 맥동이 생겨 출력 토크에 영향이 나타는 것을 알 수 있었다.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.276-279
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• 2001

Direct torque control(DTC) is known to produce quick response in ac drives. Some drawbacks of the classical DTC are the relatively large torque ripple in a low speed range and notable current pulsation during steady state. They are reflected speed response and increased acoustical noise. In this paper, The DTC quick response are preserved at transient state, while better qualify steady state performance is produced by Space Vector Modulation(SVM). It is able to reduce the acoustical noise, torque ripple and current pulsation during steady state. The system presented are closed loop stator flux and torque observer for wide speed range that inputs are currents and voltages sensing of motor terminal. Simulation results for the 2.2kw general purposed induction motor are presented and discussed.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.8 no.5
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• pp.65-69
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• 1994

본 논문은 스위치드 릴럭턴스 전동기의 디지털 속도제어시스템의 개발에 관한 연구이다. 전동기의 운전중 토오크의 맥동을 저감하기 위해 평탄 상전류(flat-topped phase current)가 되도록 전원부에 고속초퍼를 사용하여 운전조건에 따라 상전압을 제어하였다. 또한 토크 발생영역을 최대화하기 위한 제어방식을 제안하고 이를 위한 여자조건을 산정하였다. 제안한 전압 및 위상각 제어방식을 이용하여 페루우프 속도제어시스템을 구성하였으며, 제어회로는 마이크로프로세서를 사용하였다. 제안한 이론의 타당성을 확인하기 위해 실험결과를 보였다.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.610-614
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• 2000

Torque pulsation generated in every commutation period is the main drawback of BLDC motor which deteriorates the precision of BLDC motor. Many methods to solve this problem have been proposed. In this paper a new torque model considered with decaying phase back EMF is introduced and from it the cause of torque pulsation in commutation period is analyzed. Form this analysis new algorithms to reduce the torque pulsation by commutation time are proposed and with simulation the validity is verified.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.342-346
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• 1998

The brushless DC motor with trapezoidal back emfs has torque ripple due to phase commutation. The torque ripple generates noise and vibration and cause errors in position control so this makes the brushless DC motor less suitable for high performance servo applications. In this paper, we propose a new current control method to reduce the torque ripple due to commutation, when the unipolar PWM method is applied for the phase current control of brushless DC motor.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.210-212
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• 2005

최근 급속도로 발전하고 있는 산업분야에서 요구되는 서보 시스템에서 빠른 응답특성, 고도의 정밀성 그리고 안전성에 대한 요구가 커지고 있는 실정이다. 본 논문에서는 이러한 요구에 따라 5상 IPM(Five-phase IPM)의 DTC(Direct torque control)에 대해 고찰하였으며, Texas Instruments사에서 전동기 제어 전용으로 개발된 DSP칩인 TMS320F2812를 이용하여 디지털적으로 제어 알고리즘을 구성하였다. 5상 전동기는 현재 산업현장에서 일반적으로 널리 사용되고 있는 삼상 전동기에 비해 안정성이 높고, 상당 전압의 변화 없이 고정자 전류를 줄일 수 있고, 토크 맥동의 주파수를 높이고 결과적으로 토크의 크기를 감소시킬 수 있다는 여러 가지 장점을 가지고 있으며, 특히 안정성을 요구하는 항공기(Aerospace applications), 전기자동차 및 하이브리드 자동차(Electric or hybrid vehicles)등의 특수한 영역에서 요구가 계속 증가되고 있다. 따라서 본 논문에서는 5상 IPM의 DTC에 대한 특성을 실험을 통하여 확인하였다.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.2
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• pp.58-67
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• 1995

The paper describes the variation of magnetic fields caused by the operation of induction motors. The measuring system consists of the self-integrating magnetic field sensor, amplifier, and active integrator. From the calibration experiments, the frequency bandwidth of the magnetic field measuring system ranges from 20[Hz] to 300[kHz] and sensitivity is 0.234(mV/$\mu\textrm{T}$]. The magnetic fields generated under steady state and starting operations of duction motor are recorded by the proposed measuring system, and the fast Fourier transformation(FFT) of the measured data is performed to analyze the harmonic components. A single pulsed magnetic field is strongly caused by direct starting the induction motor, and its peak value is greater than 5 times as compared with the steady state value. The long transient duration and high intensity originates from the large inductance and dynamic characteristic of the induction motor, During the steady state operation of induction motor, subharmonics of magnetic field components, which depend on the pole number of induction motor, are observed. The lower order power-line harmonics can be inferred from the voltage flicker and current ripple which are derived from the torque fluctuation of induction motor. In the case of the induction motor drived by inverter, the harmonics of magnetic field are much more than those caused by direct starting method and are found generally to increase with decreasing the driving frequency.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.2
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• pp.138-147
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• 2009

In this paper, improved direct torque control(DTC) system for five-phase squirrel-cage induction motor(IM) is proposed. Due to the additional degrees of freedom, five-phase 1M drives present unique characteristics. Also five-phase motor drives possess many other advantages compared with the traditional three-phase motor drive system, such as reducing an amplitude of torque pulsation and increasing the reliability. The DTC 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 into the three-phase inverter. However, five-phase motor has structural drawback of 3rd space-harmonics current component, it is necessary to controlled 3rd harmonic current. So to control 3rd harmonic current and enhance dynamic characteristics of five-phase squirrel-cage IM drive, modified DTC method should be demanded. The characteristics and dynamic performance of traditional five-phase DTC are analyzed and new DTC for five-phase IM is presented. A more precise flux and torque control algorithm for the drives can be suggested and explained For presenting the superior performance of the proposed direct torque control, experimental results are presented using a 32-[bit] fixed point TMS320F2812 digital signal processor with 2.2[kW] induction motor.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.986-988
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• 2001

This paper presents a digitally speed sensorless control system for induction motor with direct torque control (DTC). Some drawbacks of the classical DTC are the relatively large torque ripple in a low speed range and notable current pulsation during steady state. They are reflected speed response and increased acoustical noise. In this paper, the DTC quick response are preserved at transient state, while better qualify steady state performance is produced by space vector modulation (SVM). The system are closed loop stator flux and torque observer for wide speed range that inputs are currents and voltages sensing of motor terminal, model reference adaptive control (MRAC) with rotor flux linkages for the speed fuming signal at low speed range, two hysteresis controllers and optimal switching look-up table. Simulation results of the suggest system for the 2.2 [kW] general purposed induction motor are presented and discussed.