• 전력전자학회논문지
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• 제12권1호
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• pp.74-80
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• 2007

본 논문에서는 2상 여자 방식으로 구동하는 전압형 인버터 스위치에 발생한 개방 고장을 검출하는 기법을 제안한다. 제안된 기법은 인버터 각 상의 하단 스위치에 전압 센서를 사용하여 동작 모드에 따라 개방 고장을 판별한다. 이는 구현이 간단하고 빠른 고장 판별이 가능하며 부하의 영향을 거의 받지 않기 때문에, 시스템의 신뢰성을 향상시킨다. 또한 4-스위치 인버터 구동을 적용한 재구성을 통하여 고장 발생시에도 고장의 영향을 최소화 하면서 연속적인 운전을 가능하게 했다. 제안된 고장 검출 알고리즘의 타당성은 실험결과로 검증한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.172-174
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• 1994

Due to the environmental considerations and the energy crisis, there has been a revival of electric vehicles since 1960s. Research and development work concerning with electric vehicles (EVs) was becoming more intense in last decade. As compared with conventional internal combustion engine (ICE) cars, EVs have the advantages of clean, quiet, better energy efficiency, less maintenance and improving the load factor of electric power systems. However, EVs usually have a snort running range, bad acceleration performance and high initial cost. The main reason for these shortcomings is the low figure of energy density and the high per energy cost of battery at present technology state. So it is very important to optimize the overall drive system design with respect to the maximum utilization of battery, energy, motor torque and inverter power. This paper describes a demonstration model of electric car which is driven by 4-wheel direct method using the vector control.

• 한국산업융합학회 논문집
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• 제25권6_2호
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• pp.1003-1008
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• 2022

This paper proposes a method related to fault tolerance operation and characteristic analysis of asymmetric 6-phase permanent magnet synchronous motor. In general, motor drive systems with multi-phase structures can be continuously operated despite a reduction of power and speed by using a phase changeover or control techniques according to the failures. As a result, it is widely used in industrial fields such as aviation and defense, which require high efficiency and high reliability. In this paper, the second order ripple of the electrical fundamental freuqnecy occurs in the dq-axis currents of the synchronous coordinate system through mathematical analysis according to the switch open of the dual 3-phase inverter. Therefore, the fault tolerant operation method is presented by applying the fault detection method with a constant cycle for continuous operations. The effectiveness of the proposed fault tolerance operation method is verified through the several experiments.

• 전력전자학회논문지
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• 제4권5호
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• pp.483-490
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• 1999

본 논문은 전동기 과전압 억제용으로 사용되는 인버터 출력 리액터의 최적 설계 방식을 제시하고 있다. 전력선의 길이가 상대적으로 짧은 엘리베이터 구동 시스템의 인버터 출력단에 리액터를 사용하는 경우, 전동기 선간의과 전압 특성을 과 전압 동작 주파수인 상당한 고 주파수 대역에서의 출력 리액터와 전동기 특성에 의해 좌우된다. 따라서, 고 주파수 대역에서의 출력 리액터 및 전동기의 동작 특성을 분석하고, 출력 리액터의 필요 파라미터를 추출하였다. 이를 리액터의 설계 변수하고, 리액터의 고 주파수 특성을 고주파수 특성을 고려하여, 새로운 구조의 출력 리액터 설계방식을 제안하였다. 통상의 출력 리액터와 제안된 방식의 출력 리액터를 용량 15kW급의 엘리베이터 유도 전동기 구동 시스템에서 비교 실험하여, 제안된 방식의 효과를 검증하였다.

• Journal of Electrical Engineering and Technology
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• 제2권4호
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• pp.468-477
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• 2007

The DTC of voltage source inverter-fed PMSMs is based on hysteresis controllers of torque and flux. It has several advantages, namely, elimination of the mandatory rotor position sensor, less computation time, and rapid torque response. In addition, the stator resistance is the only parameter, which should be known, and no reference frame transformation is required. The DTC theory has achieved great success in the control of induction motors. However, for the control of PMSM drives proposed a few years ago, there are many basic theoretical problems that must be clarified. This paper describes an investigation into the effect of the zero voltage space vectors in the DTC system and points out that if using it rationally, not only can the DTC of the PMSM drive be driven successfully, but torque and flux ripples are reduced and overall performance of the system is improved. The implementation of DTC in PMSM drives is described and the switching tables specific for an interior PMSM are derived. The conventional eight voltage-vector switching table, which is namely used in the DTC of induction motors does not seem to regulate the torque and stator flux in a PMSM well when the motor operates at low speed. Modelling and simulation studies have both revealed that a six voltage-vector switching table is more appropriate for PMSM drives at low speed. In addition, the sources of difficulties, namely, the error in the detection of the initial rotor position, the variation of stator resistance, and the offsets in measurements are analysed and discussed.

• 한국정보통신학회논문지
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• 제16권12호
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• pp.2708-2715
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• 2012

본 논문은 모델기준적응제어 및 직접토크제어 방식을 이용한 새로운 유도전동기의 센서리스 속도제어 방법을 제안한다. 모델기준적응제어는 기준모델과 조정모델을 설정하고 이들의 출력을 비교하여 조정모델 및 제어를 위한 속도 추정값을 얻는 제어법이다. 그리고 직접토크제어는 토크와 자속을 독립적으로 제어하는 방법으로 토크, 자속 지령치와 전동기 고정자 전압, 전류 값을 이용해 추정한 토크, 자속을 비교하여 히스테리시스 밴드를 거쳐 그 오차를 가장 최소화하기 위한 전압벡터를 선정하여 출력하는 방법이다. 본 논문에서는 제안한 방식의 이론적인 배경 및 타당성에 대해 기술하였으며 모의실험을 통해 제안된 방식의 우수성을 검증하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.1020-1022
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• 2001

because the output of solar cell is direct, it is necessary to install D/A converter system for A.C load, and in case of driving utility line system, it is possible to drive system relation when the system supplies sinusodal current ant voltage having unit power factor. As the characteristics of the soar cell output the is influenced by dailysunight charge, for more electric power it is essential to control the direction toward the san so that the driving point of solar cell can always operate near maximum output point. PWM modulation device among electric power converters must have stable modulation at anytime when it includes noise-factors such as noise-wave and noises on electric voltage wave, a synchronous signal system. In dealing with synchronous signal for control and control signal by microprocessor, it is necessary to compensate it because there is time difference between sample paint and carrier wave. On this papers, single phase PWM current type invertor controled the solar cell having typical voltage dropping character has optimun short current in short, reduces D.C reactance, composes controller for modulation and keeps lower harmonic and high power factor keeping maximum output of solar cell according daily sunlight charge variation.

• 전기학회논문지P
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• 제66권2호
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• pp.69-75
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• 2017

The gas turbine static starter rotates the stationary synchronous machine by the interaction of the rotor and the stator. The detection from the initial position of the rotor has been an important issue to drive with optimum torque. Previously, the gas turbine starter was used by attaching the encoder to the synchronous machine, but the position and velocity of the rotor have been estimated by sensor-less method until recently due to the difficulty in attaching and detaching and damage caused by the shaft voltage noise. In this paper, Rotor initial(stationary state) position estimation, forced commutation control(speed less than 10%), and natural commutation control(speed more than 10%) method using magnetic flux with integrated terminal voltage were presented and the sensor-less speed control performance was verified. As a result of making and evaluating the 29 kVA synchronous machine and the starting device, the performance of each control mode was satisfactory. Furthermore, the applied technology is expected to be used for the development of the gas turbine starter of tens of MW class and the field application.

• Journal of Advanced Marine Engineering and Technology
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• 제40권9호
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• pp.805-811
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• 2016

본 논문은 플래너 버스바가 적용된 BLDC 전동기 드라이브 시스템에서, 직류단 캐패시터 전단 전류를 이용한 BLDC 전동기의 상전류 추정 알고리즘을 제안한다. 플래너 버스바는 기생 인덕턴스의 크기를 최소화하여 스위칭 시 스파크에 의한 소자 파손을 방지하고, EMC (ElectroMagnetic Compatibility) 특성을 향상시킨다. 하지만 플래너 버스바의 장점을 극대화하기 위해서는 직류단 캐패시터의 전단에 전류 센서를 설치할 수밖에 없는 구조적 제약이 따른다. 직류단 캐패시터 전단에 설치된 전류 센서는 캐패시터에 흐르는 전류와 인버터 입력전류의 합을 측정하게 된다. 따라서 직류단 캐패시터 전단 전류로부터 인버터의 입력전류를 정확하게 추출하는 것이 BLDC 전동기의 전류 제어를 위해서는 필수적이다. 본 논문에서는 BLDC 전동기의 온/오프 구간 동안의 등가 회로를 분석하여 캐패시터 전단 전류로부터 인버터 입력전류를 추정하는 알고리즘을 제안하였다. 제안된 알고리즘은 실험을 통해 그 타당성을 검증하였다.

• Journal of Power Electronics
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• 제18권6호
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• pp.1729-1750
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• 2018

Voltage source inverters (VSIs) are widely used to drive induction motors in industry applications. The quality of output waveforms depends on the switching sequences used in pulse width modulation (PWM). In this work, all existing optimal space vector pulse width modulation (SVPWM) switching strategies are studied. The performance of existing SVPWM switching strategies is optimized to realize a tradeoff between quality of output waveforms and switching losses. This study generalizes the existing optimal switching sequences for total harmonic distortions (THDs) and switching losses for different modulation indexes and reference angles with a parameter called quality factor. This factor provides a common platform in which the THDs and switching losses of different SVPWM techniques can be compared. The optimal spatial distribution of each sequence is derived on the basis of the quality factor to minimize harmonic current distortions and switching losses in a sector; the result is the minimum ripple loss SVPWM (MRSLPWM). By employing the sequences from optimized switching maps, the proposed method can simultaneously reduce THDs and switching losses. Two hybrid SVPWM techniques are proposed to reduce line current distortions and switching losses in motor drives. The proposed hybrid SVPWM strategies are MRSLPWM 30 and MRSLPWM 90. With a low-cost PIC microcontroller (PIC18F452), the proposed hybrid SVPWM techniques and the quality of output waveforms are experimentally validated on a 2 kVA VSI based on a three-phase two-level insulated gate bipolar transistor.