• Journal of Power Electronics
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• 제19권3호
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• pp.727-743
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• 2019

This paper presents a pulse-width modulation strategy to eliminate the common mode voltage (CMV) with reduced CMV spikes in multilevel inverters since a high CMV magnitude and its fast variations dv/dt result in bearing failure of motors, overvoltage at motor terminals, and electromagnetic interference (EMI). The proposed method only utilizes the zero CMV states in a space vector diagram and it is implemented by a carrier-based pulse-width modulation (CBPWM) method. This method is generalized for odd number levels of inverters including neutral-point-clamped (NPC) and cascaded H-bridge inverters. Then it is extended to the over-modulation mode. The over-modulation mode is implemented by using the two-limit trajectory principle to maintain linear control and to avoid look-up tables. Even though the CMV is eliminated, CMV spikes that can cause EMI and bearing current problems still exist due to the deadtime effect. As a result, the deadtime effect is analyzed. By taking the deadtime effect into consideration, the proposed method is capable of reducing CMV spikes. Simulation and experimental results verify the effectiveness of the proposed strategy.

• Journal of Power Electronics
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• 제12권2호
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• pp.276-284
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• 2012

AC/AC power conversion is widely used to feed AC loads with a variable voltage and/or a variable frequency from a constant voltage constant frequency power grid or to connect critical loads to an unreliable power supply while delivering a very balanced and accurate sinusoidal voltage system of constant amplitude and frequency. The load specifications will clearly impose the requirements for the inverter stage of the power converter, while wider ranges of choices are available for the rectifier. This paper investigates the utilization of a buck-type current source rectifier as the active front-end stage of an AC/AC converter for applications that require an adjustable DC-link voltage as well as elimination of the low-frequency common mode voltage. The proposed solution is to utilize a combination of two or more zero current vectors in the Space Vector Modulation (SVM) technique for Current Sources Rectifiers (CSR).

• Journal of Power Electronics
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• 제16권6호
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• pp.2076-2084
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• 2016

In this paper, a novel scheme to eliminate common-mode voltage (CMV) is proposed for three-level neutral-point clamped (NPC) inverters. In the proposed scheme, a low-power full-bridge converter is utilized to produce compensatory voltage for CMV, which is injected into an NPC inverter through a single-phase four-winding transformer. With the proposed circuit, the power range for applications is not limited, and the maximum modulation index of the inverter is not reduced. These features are suitable for high-power medium-voltage machine drives. The effectiveness of the proposed method is verified by simulation and experimental results.

• 전력전자학회논문지
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• 제8권1호
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• pp.89-97
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• 2003

PWM 인버터에 의해 구동리근 유도전동기에 발생되는 고주파 커먼 모드 전압은 전도성 EMI, 전통기 접지전류, 베어링 전류 및 다른 원치 않는 결과의 주원인이 된다. 인버터 제어의 무효벡터 스위칭 상태는 나머지 유효벡터 스위칭 상태에 비교하여 큰 커먼 모드 전압을 일으킨다. 그러므로 이 논문은 커먼 모드 전압을 완화하는 스위칭기법을 다룬다. 즉 정현파 PWM 기법을 기본으로 한 커먼 모드 전압 제거방법을 제안하였다. PWM 신호는 각자의 정현과 기준신호와 120$^{\circ}$위상차가 나는 3개의 캐리어 파형과 비교하여 발생된다. 시뮬레이션과 실험적 결과는 제안된 PWM 기법에서 커먼 모드 전압이 종래의 PWM 기법보다 약 66% 더 저감됨을 보였다.

• 전력전자학회논문지
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• 제14권4호
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• pp.285-292
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• 2009

본 논문은 다이오드 정류기와 Z-소스 인버터로 교류전동기 구동 시 암 단락 (shoot-through) 상태와 비 암 단락 상태를 나누어 각각 등가회로를 구성하고 공통모드 전압을 분석한다. 음의 값의 공통모드 전압을 감소시키기 위하여 암 단락 시간 제어와 함께 영전압 벡터인가 구간을 제거하는 변형 공간벡터변조기법을 제시한다. PSIM과 32-비트 DSP를 사용한 실험 및 시뮬레이션 결과를 통하여 음의 공통모드전압이 50%이상 감소됨을 확인하였다.

• Journal of Power Electronics
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• 제18권3호
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• pp.923-930
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• 2018

Based on the application of an integrated dynamic brake (IDB) system that uses a PWM inverter fed-AC motor drive to operate the piston, a new active zero state PWM (AZSPWM) is proposed to improve the stability and reliability of the IDB system by suppressing the conducted electro-magnetic interference (EMI) noise under a wide range of load torque. The new AZSPWM reduces common-mode voltage (CMV) by one-third when compared to that of the conventional space vector PWM (CSVPWM). Although this method slightly increases the output current ripple by reducing the CMV, like the CSVPWM, it can be used within the full range of the load torque. Further, unlike other reduced common-mode voltage (RCMV) PWMs, it does not increase the switching power loss. A theoretical analysis is presented and experiments are performed to demonstrate the effectiveness of this method.

• 전력전자학회논문지
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• 제9권5호
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• pp.507-515
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• 2004

고속 스위칭 소자의 출현과 함께 높은 전압 상승률(dv/dt)은 PWM 인버터에 EMI 노이즈 및 축 전압 그리고 베어링 누설전류 등의 문제 등을 발생시키고 있다. 본 논문에서는 유도전동기 시스템에서의 새롭게 개발된 전도성 EMI 저감 SVPWM 기법의 응용에 대하여 기술한다. 새롭게 개발된 커먼모드 전압제거 SVPWM 기법은 인버터 제어에 있어서 영벡터 상태를 사용하지 않고 종래의 PWM 기법에 비하여 커먼모드 전압의 감소가 가능하다. 소프트웨어 접근에 의한 제안된 기법의 타당성은 시뮬레이션과 실험적 결과를 통하여 확인하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2015년도 전력전자학술대회 논문집
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• pp.383-384
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• 2015

This paper presents a new space vector modulation (SVM) method for indirect matrix converters (IMCs) to reduce commonmode voltage as well as minimize output current ripple in a high voltage transfer ratio. In the proposed SVM, the three-vector modulation scheme is used in the rectifier stage, while the nonzero state modulation technique, where the three nearest active vectors are selected to synthesize the desired output voltage, is applied to inverter stage to reduce the CMV. The proposed SVM method can significantly reduce the output current ripple and common-mode voltage of the IMC without any extra hardware. Simulated results are provided to demonstrate the effectiveness of the proposed SVM method.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2015년도 추계학술대회 논문집
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• pp.209-210
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• 2015

This paper presents a new model predictive control method without the effect of a weighting factor in order to reduce common-mode voltage (CMV) for a three-phase voltage source inverter (VSI). By utilizing two active states with same dwell time during a sampling period instead of one state used in conventional method, the proposed method can reduce the CMV of VSI without the weighting factor. Simulation is carried out to verify the effectiveness of the proposed predictive control method with the aid of PSIM software.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.438-442
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• 2001

Much attention has given to EMI effects created by variable speed ac drive system. This paper focuses on the switching technique to mitigate common mode voltage. Zero switching states of inverter control invoke large common mode voltage. Using inversed carrier wave, zero switching states are removed. In addition, proposed technique is easy to apply to existing 2-level inverter design. And common mode mitigation technique for sinusoidal PWM is also presented. Proposed switching technique is implemented with a 2.2kw 1735rpm induction motor.