• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.500-503
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• 1997

In this paper, we investigate the control methodology of inverter Airconditioner, using the three dimensional vector scheme. The method of three dimensional vector aims at the determination of optimal switching patterns for PWM to reduce switching loss and to improve the performance supplied voltage. The induction motors are widely used for home Airconditioners. These motors can be classified into two types: on or off control of Airconditioner and the speed control of motor. For speed control of motors, generally PWM methods are used. The PWM method based upon the modulation of triangular wave can not afford to supply line voltage to the motor sufficiently because of the capacity of processing speed of micro processors. Therefore airconditioner can not be operated efficiently. This problem can be solved with the method of three dimensional vector since it can increase the supplied voltage and maximum operating frequency of motor to 173V and 96Hz, respectively. As the result, this method shows 10 - 15% increase of voltage and 10% increase of operating frequency over the modulation of triangular wave. According to a theoretical study, the number of switching in the method of three dimensional vector is smaller than that of the modulation of triangular wave. The power consumption can be reduced and the supplied voltage can be increased. In other words, the efficiency of Airconditioner can be improved. We show that the method of three dimensional vector can supply higher voltage than the modulation of triangular method through the experiments and verify the degree of improvement of efficiency theoretically.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.443-445
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• 1995

Since the residential load is an AC load, while the output of solar cell is a DC power, the photovoltaic system needs the DC/AC converter to utilize solar cell and must provide the sinusoidal wave current and voltage with unity power factor in the case of driving to Interact with utility line. It is always necessary for the output of solar cell to operate in the vicinity of maximum power point, since it is greatly fluctuated by insolation. This paper treats that we will constitute a single phase PWM voltage source inverter and trace the modulation index which always maximize the output of solar cell in propotion to insolation variation and prove it by simulation that we can provide current wave, which is nearly sinusoidal wave with unity power factor, for load and utility line.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 추계학술대회 논문집 학회본부
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• pp.277-280
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• 1988

In the current-controlled PWM, the actual current tracks the sinusoidal reference wave within desired hyeteresis band. This paper au99e61s the current control scheme for voltage-fed single-phase inverter and presents the simulation results. It is expected that the inverter with this control method produces no significant lower-order harmonics.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 전력전자학술대회 논문집
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• pp.287-290
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• 1998

This paper presents PWM method which modulates two third period only during one cycle of power converter. This method is compared with the conventionl sinusoidal modulation method applying to the power converter with large capacity necessitating low switching frequency. The presented modulation method enables to reduce power semiconductor rating, minimize switching loss, and improve the current wave form.

• 한국조명전기설비학회지:조명전기설비
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• 제2권4호
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• pp.70-74
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• 1988

계단파 5전위 PWM 출력전압은 CTI회로를 구성하는 스위칭 소자의 구동신호에 의하여 이루어진다. 이 CTI회로를 구동시키기 위한 구동신호는 Natural Sampling 방식의 변조신호를 10-6 범위인 변환 오차로 디지틀 변환하고, 이 신호의 데이터에 의한 마이크로프로세서 운전 시스템을 구성하였다. 이 방식에 의하면, CTI회로의 V/F제어를 위한 1[Hz]~60[Hz]의 시스템에 소요되는 메모리의 용량은 어드레스 카운터방식에 비하여 0.8%이었다.

• 수산해양기술연구
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• 제35권3호
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• pp.328-334
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• 1999

A fish pump makes very important roles in an automation system of an aquaculture farm, thus it has been used widely in order to transfer fishes from one place to the other place automatically. In spite of its significant roles, the efforts for developing performance and promoting efficiency of the fish pump are not sufficient yet. In this paper, a method which makes the fish pump automation system is suggested. Automation of the fish pump can be accomplished by using variable voltage and variable frequency inverter system including induction motors. Especially, very simple logic to generate Pulse width Modulation(PWM) wave to control induction motor efficiently and three steps speed control method to regulate liquid quantity of the fish pump simply are suggested. Owing to the simplifies speed control and PWM wave generation technique, a cheaper microprocessor, 80C196KC, than a digital signal Processor(DSP) can be used to operate control algorithm in induction motor systems for real time control Also, a new idea of remote control for the simplifies novel inverter system by Programmable logic Controller(PLC) without special output unit, digital to analog converter(D/A), is suggested in this paper. Consequently the function of reliability, availability and serviceability of the fish pump system are developed. It will be expected to contribute expanding of application of the fish pump in aquaculture farms because the system can reduce energy consumption and some difficulties according to manual operation prominently.

• 전자공학회논문지C
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• 제35C권11호
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• pp.21-30
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• 1998

본 논문에서는 FPGA를 이용하여 산업용 구동장치로 널리 사용되고 있는 유도 전동기의 디지털 전류 제어시스템을 구현하였다. 이를 위해 VHDL을 이용하여 FPGA를 설계하였으며 이 FPGA는 PWM 발생부, PWM 보호부, 회전속도 검출부, 프로그램 폭주 방지부, 인터럽트 발생부, 디코더 로직부, 신호 지연 발생부 및 디지털 입·출력부로 각각 구성되어있다. 본 FPGA의 설계시 고속처리의 문제점을 해결하기 위해 클럭전용핀을 활용하였으며 또한 40 MHz에서도 동작할 수 있는 삼각파를 만들기 위해 업다운 카운터와 래치부를 병렬 처리함으로써 고속화하였다. 특히 삼각파와 각종 레지스터를 비교 연산할 때 많은 팬아웃 문제에 따른 게이트 지연(gate delay) 요소를 줄이기 위해 병렬 카운터를 두어 고속화를 실현하였다. 아울러 삼각파의 진폭과 주파수 및 PWM 파형의 데드 타임 등을 소프트웨어적으로 가변 하도록 하였다. 이와 같은 기능들을 FPGA로 구현하기 위하여 퀵로직(Quick Logic)사의 pASIC 2 SpDE와 Synplify-Lite 합성툴을 이용하여 로직을 합성하였다. 또한 Verilog HDL 환경에서 최악의 상황들(worst cases)에 대한 최종 시뮬레이션이 성공적으로 수행되었다. 아울러 구현된 FPGA를 84핀 PLCC 형태의 FPGA로 프로그래밍 한 후 3상 유도전동기의 디지털 전류 제어 시스템에 적용하였다. 이를 위해 DSP(TMS320C31-40 MHz)와 FPGA, A/D 변환기 및 전류 변환기(Hall CT) 등을 이용하여 3상 유도 전동기의 디지털 전류 제어 시스템을 구성하였으며, 디지털 전류 제어의 효용성을 실험을 통해 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.1071-1073
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• 1992

PWM technique is widely applied to the control of AC machines. In this paper a new PWM technique for real-time implementation of variable-frequency sinusoidal PWM is introduced. In the proposed algorithm, a low pass filter is used and the switching state is so determined as to minimize the difference between the reference wave and the output of the filter.

• 전기학회논문지P
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• 제63권3호
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• pp.125-130
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• 2014

This paper is research result for a development of solar cell silicon ingot glowing(SCSIG) PWM converter system for 120[kW] 3[kA]. The system include 3-phase AC-DC rectifier diode converter of input voltage AC 460[V] and 60[Hz], DC-AC single phase full bridge PWM inverter of high frequency, AC-DC single-phase full wave rectifier using center-tapped of transformer for low voltage 50[V] and large current 3,000[A], carbon resistor load 0.2 [$m{\Omega}$]. PWM switching frequency for IGBT inverter control set 15KHz. The suggested researching contents are designed data sheets of power converter system, PSIM simulation, operating characteristics and analysis results of developed SCSIG system.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.288-291
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• 2007

Since the residential load is an AC load and the output of solar cell is a DC power, the photovoltaic system needs the DC/AC converter to utilize solar cell. In case of driving to interact with utility line, in order to operate at unity power factor, converter must provide the sinusoidal wave current and voltage with same phase of utility line. Since output of solar cell is greatly fluctuated by insolation, it is necessary that the operation of solar cell output in the range of the vicinity of maximum power point. In this paper, DC/AC converter is three phase PWM converter with smoothing reactor. And then, feedforward control used to obtain a superior characteristic for current control and digital PLL circuit used to detect the phase of utility line.