• Journal of Power Electronics
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• 제19권6호
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• pp.1515-1526
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• 2019

Ear-piercing high-frequency noise from electromagnetic vibrations in motors has become unacceptable in sensitive environments, due to the application of pulse width modulation (PWM) and in consideration of switching losses. This paper proposed a synchronous periodic frequency modulation (SPFM) method based on the interleaving technique for paralleled three-phase voltage source inverters (VSIs) to eliminate PWM vibration noise. The proposed SPFM technique is able to effectively remove unpleasant high-frequency vibration noise as well as acoustic noise more effectively than the conventional periodic carrier frequency modulation (PCFM) and interleaving technique. It completely eliminates the vibration noise near odd-order carrier frequencies and reduces the PWM vibration noise near even-order carrier frequencies depending on the switching frequency variation range. Furthermore, the SPFM method is simple to implement and does not employ additional circuits in the drive system. Finally, the effectiveness of the proposed method has been confirmed by detailed experimental results.

• 한국공작기계학회논문집
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• 제13권2호
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• pp.69-74
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• 2004

In general the surge pressure generated in hydraulic systems causes noise, vibration and odd effect to the system. To reduce the surge pressure, high frequency PWM control of 20KHz was attempted. To estimate the braking noise caused by surge, a vehicle equipped with on-board ABS hydraulic modulator has been experimented with respect to the various breaking condition. Thorough this experiments, it was found that breaking noise has been reduced using high frequency PWM control method compare with low frequency method. To evaluate high frequency control m practice, including verification of general functionality, EMI tests was experimented. Its was found that it is necessary to have the solution to electromagnetic interference(EMI) generated by switching elements.

• 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.

• Journal of information and communication convergence engineering
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• 제6권3호
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• pp.305-309
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• 2008

This paper presents an innovative prototype of a new conceptual electromagnetic induction eddy current based fluid heating appliance using voltage-fed quasi resonant zero voltage soft switching PWM high-frequency inverter using IGBTs, which can operate at a constant frequency variable power regulation scheme. The promising simple high efficient low noise inverter type electromagnetic induction eddy current based pipeline fluid heating appliance is proposed for saturated steam generator, superheated steam generator, hot water and hot air producer, metal catalyst heating for exhaust gas cleaning in engine. Under these technological backgrounds, a novel electromagnetic induction eddy current Dual Packs Heater(DPH) based pipeline fluid heating incorporates thin metal layer type package for continuous fluid heating appliances applying two types of voltage-fed quasi load resonant ZVS-PWM high frequency inverter. The unique features of a novel electromagnetic induction eddy current DPH based continuous pipeline fluid heating appliance is illustrated on the basis of simulation and discussed for the steady state operating characteristics and experimental results.

• 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.

• 조명전기설비학회논문지
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• 제12권4호
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• pp.90-99
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• 1998

DC/DC 컨버터의 리액티브 성분의 물리적 크기를 저감하고 동특성을 개선하기 위해서는 동작 스위칭 주파수 를 증가시키는 것이 바람직하다. 그러나 이것은 발열 및 스트레스로 인한 파워 소자의 파괴, 스위칭 손실 증가 로 인한 효율 감소 및 EM! 동의 문제가 발생한다. 따라서, 본 논문에서는 이러한 문제점을 해결하기 위해 보조 회로를 웅용한 소프트 스위칭 Forward-Flyback PWM DC/DC 컨버터를 제안하였다. 시뮬레이션 및 실험 결과로부터 제안한 컨버터의 타당성을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.1063-1066
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• 1992

As the adjustable speed drives by means of PWM inverter are applied to a wider field of industries, the demands for lower acoustic noise caused by modulation is becoming more intense. With the development of high speed power semiconductor device such as the IGBTs, a higher carrier frequency can be adopted to increase the switching frequency to the supersonic range. The optimal magnitude of this signal is determined so that the sideband components near the carrier frequency are minimized

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권3호
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• pp.313-321
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• 2014

A low-power low-cost polar transmitter for EDGE is designed in $0.18{\mu}m$ CMOS. A differential delta-sigma modulator (DSM) tunes a three-terminal voltage-controlled oscillator (VCO) to perform RF phase modulation, where the VCO tuning curve is digitally pre-compensated for high linearity and the carrier frequency is calibrated by a dual-mode low-power frequency-locked loop (FLL). A digital intermediate-frequency (IF) pulse-width5 modulator (PWM) drives a complementary power-switch followed by an LC filter to achieve envelope modulation with high efficiency. The proposed transmitter with 9mW power dissipation relaxes the time alignment between the phase and envelope modulations, and achieves an error vector magnitude (EVM) of 4% and phase noise of -123dBc/Hz at 400kHz offset frequency.

• 대한전자공학회논문지
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• 제25권1호
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• pp.42-48
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• 1988

MM(multimode) PWM(pulse width modulation) Suitable for high performance and harmonic effects minimization of VSI (voltabge source invertetr)-IM (induction motor)drive system is proposed. The approximated optimal, suboptimal and optimal PWM are implemented in the low frequency range, while square wave operation is realized in the hibh frequency range. The pulse width Modulator is capable of generating control signals to a transistorized inverter operating at about 1KHz. All functions except digital comparison have been implemented in softyware making the scheme economical, flexible and reliable. Pulse width modulator is built and tested experimentally. In order to confirm the effectiveness and the reliability of the theoretical proposition, this scheme is applied to 1Hp, Three phase IM. As results, it is concluded that the scheme of MM PWM is superior to other conventional switching scheme through the discussions or analysis carried out on the items such as line-to-line voltage, current and spectrum of current harmonic components observed at the output terminal of inverter, noise level of motor.

• 전기학회논문지P
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• 제65권3호
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• pp.158-164
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• 2016

In this paper, a high frequency flyback type zero voltage soft switching PWM DC-DC converter using IGBTs is proposed. Effective applications for this power converter can be found in auxiliary power supplies of rolling stock transportation and electric vehicles. This power converter is basically composed of active power switches and a flyback high frequency transformer. In addition to these, passive lossless snubbers with power regeneration loops for energy recovery, consisting of a three winding auxiliary high frequency transformer, auxiliary capacitors and diodes are introduced to achieve zero voltage soft switching from light to full load conditions. Furthermore, this power converter has some advantages such as low cost circuit configuration, simple control scheme and high efficiency. Its operating principle is described and to determine circuit parameters, some practical design considerations are discussed. The effectiveness of the proposed power converter is evaluated and compared with the hard switching PWM DC-DC converter from an experimental point of view and the comparative electromagnetic conduction and radiation noise characteristics of both DC-DC power converter circuits are also depicted.