• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권11호
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• pp.547-552
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• 2005

This paper describes a pseudo-random carrier PW technique for the power converters. The proposed method generates a new pseudo-random carrier by randomly composing a carrier with fixed frequency and a carrier with opposition phase. To confirm the validity of the proposed method, a single-phase multi-level inverter was implemented and tested. The experimental results show that the output voltage and current harmonics spectra of an inverter have broadening effect of harmonics, as only simple composition of fixed frequency carries.

• 조명전기설비학회논문지
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• 제28권11호
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• pp.100-105
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• 2014

In this paper, Uninterruptible Power Supply(UPS) Inverter system using Carrier Frequency Modulated PWM (CFM-PWM) is proposed to reduced harmonics and electromagnetic noise. Power conversion of UPS system is executed by the ON-OFF operation of semiconductor switching devices. However, this switching operation causes the surge and EMI which deteriorate the reliability of the UPS system. This Problems improved by Random PWM switching method. The simulation results of the proposed system was compared with the system using conventional method using Matlab/Simulink. The results show that the output voltage and current harmonics of the proposed UPS system significantly decreased and spread into wide band area by the proposed Carrier Frequency Modulated PWM(CFM-PWM) method based on the Space Vector Modulation.

• 한국철도학회논문집
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• 제15권3호
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• pp.244-250
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• 2012

본 논문에서는 차세대 고속철도 구동 인버터 시스템의 고조파로 인한 전자기적 소음을 줄이기 위해 RCF-PWM(Random Carrier Frequency Pulse Width Modulation)을 적용한 인버터 구동시스템을 개발하였다. RCF-PWM 방식은 인버터 스위칭 주파수를 전력용 반도체의 최대 스위칭 주파수와 최소 스위칭 주파수 사이에서 임의적으로 변화시키며 PWM을 수행하는 방법이다. 본 연구의 타당성을 확인하기위해서 RCF-PWM이 적용된 차세대 고속전철 시스템을 설계하여 MATLAB/Simulink 기반의 시뮬레이터를 개발하고 이를 이용하여 일정한 스위칭 주파수를 사용하는 정규적인 SVPWM 방식과 RCF-PWM 방식의 시험결과를 비교 분석하였다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권12호
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• pp.608-615
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• 2003

This paper describes an implementation of a DSP (Digital Signal Processor) controlled random carrier frequency modulation for the PWM inverter for acoustic noise reduction of induction motors. Real-time generation of the random variable and RPWM(Random PWM) along with the speed control was achieved by DSP TMS320C31. The experimental results show that the voltage and current harmonics are spread to a wide band area and the power spectrum of the acoustic switching noise was spread to create a more appealing, less annoying sound. Also, the speed response of the implemented method and the conventional method is nearly similar to each other from the viewpoint of the v/f constant control.

• 전력전자학회논문지
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• 제10권5호
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• pp.501-507
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• 2005

본 연구에서는 유도 전동기의 파워 스펙트럼 확산을 위한 LF2407 DSP기반 하이브리드 랜덤 PWM(HRPWM)을 제안하였다. 제안된 방법은 Lead-Lag 랜덤 비트를 갖는 PRBS (Pseudo-Random Binary Sequence)와 논리적으로 비교를 하기 위한 랜덤 삼각파 캐리어로 구성된다. 또한 DSP에 의하여 랜덤 수 및 PRBS 그리고 3상 기준 정현파를 실시간으로 발생하며, DSP외부의 주파수 변조기 MAX038에 의하여 랜덤 주파수의 캐리어를 발생한다. 본 연구의 타당성 검증을 위하여 제안된 기법을 3상 가변속 구동장치에 적용하였으며, 종전의 방법과 전압 및 전류 그리고 전동기 소음의 파워 스펙트럼을 비교 검토하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.150-156
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• 2001

This paper describes an implementation of the DSP(Digital Signal Processor) based triangular carrier frequency modulated RPWM inverter drive system. The power spectrum of the noise emitted from the induction motor was measured in the anechoic chamber. The analysis of the sources for the acoustic noise and the effects of the noise reduction are confirmed by the measured spectra of the noise. Real-time RPWM along with the speed control was achieved by high speed DSP. By changing the center frequency and the bandwidth of the carrier, the proposed real-time RPWM scheme can be used as an efficient switching frequency band acoustic noise reduction method for the inverter drive system with variant load conditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 학술대회 논문집 전문대학교육위원
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• pp.154-158
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• 2006

The switching-mode power converter has been widely used because of its features of high efficiency and small weight and size. These features are brought by the ON-OFF operation of semiconductor switching devices. However, this switching operation causes the surge and EMI(Electromagnetic Interference) which deteriorate the reliability of the converter themselves and entire electronic systems. This problem on the surge and noise is one of the most serious difficulties in AC-to-DC converter. Random Pulse Width Modulation (RPWM) is peformed by adding a random perturbation to switching instant while output-voltage regulation of converter is performed. RPWM method for reducing conducted EMI in single switch three phase discontinuous conduction mode boost converter is presented. The more white noise is injected, the more conducted EMI is reduced. But output-voltage is not sufficiently regulated. This is the reason why carrier frequency selection topology is proposed. In the case of carrier frequency selection, output-voltage of steady state and transient state is fully regulated. A RPWM control method was proposed in order to smooth the switching noise spectrum and reduce it's level. Experimental results are verified by converter operating at 300v/1kW with $5%{\sim}30%$ white noise input. Spectrum analysis is performed on the Phase current and the CM noise voltage. The former is measured with Current Probe and the latter is achieved with LISN, which are connected to the spectrum analyzer respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 F
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• pp.2058-2061
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• 1997

A main research topic in PWM inverter drive system is to reduce the generated acoustic noise. One method to reduce the acoustic noise is to cause the switching pattern to be random. This RPWM(Random Pulse Width Modulation) technique for voltage controlled inverters is a kind of good solutions for reduction of acoustic noise and suppression of vibration. This paper describes a carrier frequency modulated real-time RPWM inverter. Changing the carrier frequency randomly, the power spectrum of tile acoustic noise was spread over the wide-band area. And experimental results showed that emitted noise is much more comportable and less annoying

• 전력전자학회논문지
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• 제7권3호
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• pp.262-271
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• 2002

견인전동기 구동시스템에 사용되는 PWM 인버터는 전력용량이 크기 때문에 스위칭주파수가 제한되며, 따라서 전자기적 가청소음이 발생한다. 이러한 가청소음을 줄이기 위하여 새로운 MRSF-PWM 방식을 제안한다. 제안한 MRSF-PWM 방식에서는 고조파를 확산시키기 위해 삼각파와 톱니파를 함께 운송파로 사용하며, 출력전압의 선형제어범위를 넓히기 위해 정현파에 3차 고조파를 주입한 파형을 기준파로 사용한다. MRSF-PWM 방식의 타당성을 검증하기 위하여 컴퓨터 시뮬레이션을 수행하였다. 그 결과, MRSF-PWM 방식이 선형성 및 고조파 확산면에서 다른 RPWM 방식보다 우수하며 가청소음 저감면에서 SPWM 방식보다 효과적임을 확인하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 추계학술대회 논문집
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• pp.54-58
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• 2004

본 연구에서는 고정 주파수를 갖는 유사 랜덤 주파수 캐리어 PW(PRC-PWM)을 제안하고 단상 5-레벨 캐스케이드 인버터에 적용하였다. 제안된 PRC-PWM의 펄스는 고정 주파수를 갖는 삼각파 캐리어와 그 역상의 삼각파 캐리어를 랜덤 비트 발생기(PRBS)에 의하여 랜덤하게 선택함으로서 새롭게 합성된 랜덤 주파수의 캐리어에서 얻고 있다. 제안된 PRC-PWM은 고정 주파수의 캐리어 합성만으로 랜덤 주파수의 캐리어를 매우 간단하게 구현할 수 있으며, R-L부하와 연결된 단상 5-레벨 캐스케이드 인버터를 제작하여 타당성을 입증하였다.