• 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

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 추계학술대회 논문집
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• pp.1-5
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• 2003

The random pulse width modulation(RPWM) on the noise and vibration abatement in inverter-fed induction motor drive is presented. This paper describes a RPWM technique based on space vector PWM strategy for shaping the switching noise spectrum in such a way it can merge with the natural system noise. To verify the validity of the proposed RPWM scheme, the experiment based on the TMS320 C3l microprocessor was executed. Finally, the simulation and experimental results will be given to demonstrate the effectiveness of the proposed RPWM technique.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.316-319
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• 1998

RPWM(Random Pulse Width Modulation) is a switching technique to spread the voltage and current harmonics on the wide frequency area. Using randomly changed switching frequency of the inverter, the power spectrum of the electromagnetic acoustic noise cab be spread to the wide-band area. The wide-band noise is much more comfortable and less annoying than the narrow-band one. So RPWM have been attracting an interest as an excellent method for the reduction of acoustic noise on the inverter drive system. In this paper a new RPPWM (Random Position PWM) is proposed and implemented. Each of three pulses is located randomly in each switching interval. Along with the randomization of PWM pulses, the space vector modulation is executed in the C167 microcontroller also. The experimental results show that the voltage and current harmonics were spread to wide band area and that the audible switching noise was reduced by proposed RPPWM method.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1998년도 창립기념 춘계학술대회 논문집
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• pp.280-286
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• 1998

In recent years, the interest in noise increases gradually and the low noise level becomes one of the important performances in electrical equipment for railway vehicle. In the auxiliary power supply, most of the noise is made by the current ripple of alternating current reactor(ACL) which filters the output voltage. And this current ripple results from the voltage harmonics across the ACL. So the noise can be reduced by eliminating the voltage harmonics across the ACL. This paper shows harmonic eliminating technique which is making gating signals of upper and lower inverter have a phase difference in the 12-step inverter type auxiliary power supply. This technique was proved by testing on the developed 180KVA auxiliary power supply using IGBT.

• 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.

• 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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• 제4권4호
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• pp.311-317
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• 1999

본 논문에서는 SEPP-LCC형 부하 공진 고주파 인버터의 한 회로형식을 제안하고, 그 동작원리에 관해서 명확히 하였다. 제안한 인버터는 스위칭 소자 양단에 병렬로 커패시터를 추가함으로써 스위칭 소자의 턴-온과 턴-오프시에 발생하는 스위칭 손실, 노이즈, 스트레스 등을 줄일 수 있다. 범용성 있는 회로해석을 위하여 무차원화 파라미터를 도입하였고, 동작특성 및 평가를 통하여 얻은 특성치를 이용하여 회로를 설계하였다. 또한, 실험을 통하여 이론해석의 정당성을 입증하였다.

• 조명전기설비학회논문지
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• 제28권12호
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• pp.116-123
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• 2014

In case of power electronics, th power loss and EMI noise of IGBT is different depends on a adopting technology with the same power rating. To reduce the EMI noise, we could increase the resistance of gate. But in this case, the power loss of IGBT is increased, In this paper, we simulated the power loss of IGBT with the speed profile of elevator by the changing IGBT type, the voltage between gate and emitter, the resistance of gate in converter and inverter for elevator. To optimize the power electronics with the satisfied life time, It is necessary that we calculate the power loss and the rise of temperature in IGBT with the adopting technology type, the resistence of gate, the voltage between gate and emitter.

• 한국ITS학회 논문지
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• 제8권5호
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• pp.98-104
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• 2009

본 논문에서는 Push-Push 구조와 고임피던스 인버터를 이용하여 개선된 VCO를 설계 및 제작하였다. 두 개의 고조파 발진기를 Push-Push 구조로 결합시킴으로써 기본주파수 억압특성을 개선하였으며, 고조파 출력을 향상시켰다. 이에 따른 위상잡음 증가는 고임피던스 인버터를 이용하여 공진기와 병렬선로 사이의 결합특성 개선을 통하여 억제하였다.

• 전기학회논문지
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• 제66권11호
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• pp.1584-1590
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• 2017

This paper presents a implementation method of reliable speed limitation controller considering motor parameter variation in high speed operation. In spinning process of drum washing machine, speed increase has to be limited when unallowable imbalance mass is detected. Otherwise, severe noise and vibration can happen because noise and vibration are proportional to imbalance mass. To detect imbalance mass, d-axis current magnitude is used. However, we have to compensate for back-emf and power supply variation by means of detecting them because d-axis current is affected by both of them. On the other hand, we have to carefully estimate back-emf because back-emf is affected by stator resistance variation and inverter voltage error. Stator resistance variation can happen by manufacturing process for mass production or temperature variation in running. And there are inverter voltage errors between command voltage from micro-computer to inverter and real voltage from inverter to motor because of rising and falling time delay and turn-on resistance of power semiconductor switch. To solve this problem, we propose 2-step align current injection method which is to inject step-wise current right before starting. By this method, we can simply obtain stator resistance by ratio of voltage without inverter voltage error and current, and we can measure inverter voltage error. So we can obtain more exact model current, and then by simple calculation with compensation gain, we can estimate more accurate motor back-emf. We show that this method works well. It is verified through experiments.