• Journal of Magnetics
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• 제18권2호
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• pp.216-219
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• 2013

In this paper, the influence of inverter switching harmonics on iron loss and PM loss of Permanent Magnet Synchronous Motor (PMSM) is numerically investigated by Finite Element Method (FEM). In particular, nonlinear FEM is applied for a multi-layered PM Synchronous Motors (PMSMs), Interior buried PMSM (IPMSM) and PM assisted Synchronous Reluctance Motor (PMa-SynRM), which are adoptively designed and compared for Electric Vehicle (EV) propulsion. In particular, iron loss and PM eddy-current loss under the real current waveform including the carrier harmonics from inverter switching are numerically analyzed with nonlinear FEM by considering the skewed stator structure employed for minimizing spatial harmonics.

• 조명전기설비학회논문지
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• 제22권12호
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• pp.64-70
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• 2008

종래의 준 랜덤 주파수 캐리어(PRC : Pseudo-Randomized Frequency Carrier) 변조기법을 3상 H-브리지 멀티레벨 인버터(HBML: H-Bridge Multi-Level Inverter)에 적용하는 경우, 스위칭 주파수의 2배 주파수 영역에서 큰 스펙트럼 클러스터가 그대로 존재하는 문제점이 있다. 본 연구에서는 서로 2배의 주파수 비율을 갖는 2개의 고정주파수 삼각파 캐리어와 3단계 멀티플렉서(MUX : Multiplexer)를 이용하여 종래의 PRC기법의 고조파 스펙트럼 확산 효과를 개선하였다. 제안된 기법은 1.5[kw]급 3상 HBML인버터 구동시스템에 적용하였으며, 종전의 방법과 제안된 방법의 전압 및 전류 고조파 스펙트럼을 비교 검토하였다.

• 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.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.742-745
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• 2005

This paper describes a simple pseudo-random carrier modulation technique for the acoustic noise reduction of the three phase multi-level inverter based motor drives. The proposed method generates a new pseudo-random carrier by randomly synthesizing a carrier with fixed frequency and a carrier with opposition phase. To confirm the validity of the proposed method, a 130v three-phase multi-level inverter was Implemented and tested. The experimental results show that the output line voltage and acoustic noise harmonics spectra of an inverter have broadening effect of harmonics, as only simple synthesis of fixed frequency carries.

• 전력전자학회논문지
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• 제23권2호
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• pp.139-146
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• 2018

This work puts forward a theoretical analysis on position estimation performance of interior permanent magnet synchronous motor (IPMSM) according to the injection frequency in carrier-based sensorless operation. The effects of spatial harmonics on inductance and voltage distortion due to the nonideal characteristics of IPMSM and inverter are examined as factors influencing the position estimation performance. Furthermore, the position estimation performance is analyzed by calculating the current at the switching instant in several operating conditions. In summary, the half switching frequency injection is more robust to the nonideal characteristics of IPMSM, especially with light load condition. The validity of the analysis is verified by the simulation and experimental results.

• 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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.302-305
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• 1995

An improved carrier PWM method for three phase voltage source inverters is proposed. The basic idea of the proposed method is deleting unnecessary 1/3 of switchings in the saw tooth carrier PWM method. The lowest frequency of the remained harmonics of this method (when the modulation index is large) is about 50% higher and the maximum modulated voltage is about 15% higher than those of the triangular carrier PWM method. This method will be useful especially in the linear feedback current control and MOSFET inverters.

• 전력전자학회논문지
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• 제14권6호
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• pp.472-480
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• 2009

본 논문은 3상 NPC형 3레벨 인버터의 과변조 SVPWM 기법과 변조비에 대한 출력전압의 고조파를 분석하였다. 3상 NPC형 3레벨 인버터는 SVPWM을 적용하여 선형영역을 0.907까지 확장하였고 과변조 영역에서는 푸리에 급수에 의한 추종전압의 보상기법을 적용하여 6 스텝영역까지 운전할 수 있도록 하였다. PWM 형태인 출력전압의 고조파 특성분석에는 PD방식의 멀티 캐리어 기법에 대하여 이중 푸리에 급수를 적용하여 해석하였다. 시뮬레이션은 PSIM을 사용하여 구현하였고 3레벨 인버터의 영역도의 각 영역에 대해서 고조파의 특성을 확인하였다. NPC형 3레벨 인버터의 고조파 분포는 선형영역에서는 캐리어 주파수의 측대 고조파가 분포되고, 과변조 영역으로 넘어가면서 기본파에 의한 고조파 성분이 점차 증가하고 캐리어 주파주의 사이드 밴드의 고조파 성분은 감소함을 확인하였다. 본 논문에서의 고조파 해석을 검증하기 위하여 동일한 조건에서 시뮬레이션과 실험을 수행하였다.

• Journal of Power Electronics
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• 제18권2호
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• pp.615-626
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• 2018

To ensure a DC current path and avoid large voltage overshoot of the DC-link inductor, alternating PWM pulses in the current-source rectifier should be supplemented by overlap time, which generates an overlap current and causes input current distortion. In this study, the influence of overlap time is illustrated by comparing the AC-side current before and after overlap time is added. The overlap current distribution caused by overlap time is discussed under different modulation carriers, including triangle carrier, positive-going carrier, and negative-going carrier. The quantitative relationship between the extra harmonics of the AC-side current and overlap time is based on the Fourier analysis. Based on the commutation analysis, a new carrier modulation scheme that can restrain overlap current is proposed. A 3 kW prototype is established to verify the effectiveness of the influence of overlap time and the proposed restraining modulation scheme.

• Journal of Power Electronics
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• 제16권2호
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• pp.512-521
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• 2016

Cascaded H-bridge multilevel (CHBML) inverters usually include a large number of isolated dc-voltage sources. Some faults in the dc-voltage sources result in unequal cell dc voltages. Unfortunately, the conventional phase-shifted carrier (PSC) PWM method that is widely used for CHBML inverters cannot eliminate low frequency sideband harmonics when the cell dc voltages are not equal. This paper analyzes the principle of sideband harmonic elimination, and proposes an improved PSCPWM that can eliminate low frequency sideband harmonics under the condition of unequal dc voltages. In order to calculate the carrier phases, it is necessary to solve transcendental equations for low frequency sideband harmonic elimination. Therefore, an approach based on the artificial bee colony (ABC) algorithm is presented in this paper. The proposed PSCPWM method enhances the reliability of CHBML inverters. The proposed PSCPWM is not limited to CHBML inverters. It can also be applied to other types of multilevel inverters. Simulation and experimental result obtained from a prototype CHBML inverter verify the theoretical analysis and the achievements made in this paper.