• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제11B권3호
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• pp.112-118
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• 2001

In the near future, the voltage of power system for passenger vehicle will be changed to 42V from existing 14V./ Because of increasing power and voltage ratings used in the vehicle the motor drive system has high switching dv/dt and it generates electromagnetic interference (EMI) To solve these problems multi-level inverter system may be used The feature of multi-level inverter is the output voltage to be synthesized from several levels of voltage Because of this feature high switching dv/dt and EMI can be reduced in the multi-level inverter system But as the number of level is increased manufacturing cost is getting expensive and system size is getting large. Because of these disadvantages the application of multi-level inverter has been restricted only to high power drives. The method to reduce manufacturing cost and system size is to integrate circuit of multi-level inverter into a few chips But isolated power supply and signal isolation circuit using transformer or opto-coupler for drive circuit are obstacles to implement the integrated circuit (IC) In this paper a drive circuit of 4-level inverter suitable for integration to hybrid or one chip is proposed In the proposed drive circuit DC link voltage is used directly as the power source of each gate drive circuit NPN transistors and PNP transistors are used to isolate to transfer the control signals. So the proposed drive circuit needs no transformers and opto-couplers for electrical isolation of drive circuit and is constructed only using components to be implemented on a silicon wafer With th e proposed drive circuit 4- level inverter system will be possible to be implemented through integrated circuit technology Using the proposed drive circuit 4- level inverter system is constructed and the validity and characteristics of the proposed drive circuit are proved through the experiments.

• 조명전기설비학회논문지
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• 제28권8호
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• pp.82-89
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• 2014

The industrial products to use single phase inverter are raised the necessity of power quality improvement, such as AC Motor Driver, Lighting, Renewable energy power converter. Also, it is increasing that applied the single phase multilevel inverter for high quality power at renewable energy power converter. Especially, the photovoltaic multilevel inverters have at least more than two DC_Link and more than one DC/DC Converter. This paper proposes a triple output DC/DC Converter with one switch for photovoltaic multilevel inverter. The proposed converter has advantages of low cost and volume because it has one switch. The operation principle of the converter is analyzed and verified. A prototype is implemented to verify of the proposed converter.

• Journal of Power Electronics
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• 제10권2호
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• pp.146-154
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• 2010

In this paper two dual output current-type inverters are proposed. These inverters have been called a current source nines-witch inverter and a current-type z-source nine-switch inverter by the authors. The proposed inverters have two independent current source outputs. Compared to two independent current source inverters, the proposed converters are implemented with fewer semiconductor switches. Space vector modulation (SVM) is proposed for these converters. Simulation results show the validity and performance of the proposed inverters.

• 전력전자학회논문지
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• 제8권6호
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• pp.478-487
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• 2003

본 논문에서는 고압 대용량 전동기 구동용 멀티레벨 인버터의 종류 및 특징을 간략히 살펴보고, 특히 입출력 전력품질이 우수하고 전압별 시리즈화가 용이한 H-브릿지 멀티레벨 인버터의 구조적 특징 및 장점을 기술하였다. 연구 개발된 3,300V lMVA 용량의 Cascaded H-브릿지 멀티레벨 인버터의 구체적인 전력회로 구조 및 설계방법, 제어기 구성 그리고 PWM 기법을 제시하였다. 또한, 실용량의 시험을 통해 H-브릿지 멀티레벨 인버터는 출력 전압 Step이 여러 단계이고 dv/dt가 적으며 입력단 THD를 크게 낮출 수 있어 성능 면에서도 여타 방식보다 우수함을 입증하였다. 또한 생산적인 측면에서도 저압 소자를 사용하여 설계하므로 기존의 생산/시험 기술과 설비를 이용할 수 있어 매우 경제적이며 Power Cell 단위 결합 구조이므로 신뢰성 측면이나 보수/유지 측면에서도 유리하다는 결론을 얻었다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.535-540
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• 1998

This paper discusses a triple stage current source GTO inverter system for high power motor drives. The energy rebound circuit of the triple stage inverter not only controls the spike voltage of the GTO inverter but also facilitates PWM control of the thyristor rectifier operated at unity fundamental input power factor. Based on Pspice simulation and experiments, the principles and PWM pulse pattern for removing specific lower harmonics in the inverter's output current are discussed in detail.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.298-301
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• 2005

The flying capacitor voltage control of the flying capacitor multi-level inverter (FCMLI) is very important for safe operation. The voltage unbalancing of flying capacitors caused serious problems in safety and reliability of system. In the FCMLI, balancing problem of the flying capacitor has its applications limited. The voltage unbalance is occurred by the difference of each capacitors charging and discharging time applied to FCMLI. This paper investigates and analyzes multi-carrier PWM methods to solve capacitor voltage balancing problem. The Phase-Shift PWM (PSPWM) method that is commonly used, The Modified Carrier-Redistribution PWM (MCRPWM) method and The Saw-Tooth-Rotation PWM (STRPWM) method are discussed and compared with respect to switching state, balancing voltage of capacitors and output waveform. These three PWM methods are analyzed by using a flying capacitor three-level inverter and provided result through simulation. Finally, the harmonics about the output voltages of their methods are compared using the harmonic distortion factor (HDF).

• 한국조명전기설비학회지:조명전기설비
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• 제11권4호
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• pp.59-65
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• 1997

이 논문에서는 형광램프용 가변출력형의 전자식 안정기의 설계방법 및 제어방법을 제안하였다. 마이크로 컨트롤러를 이용한 인버터회로의 주파수제어의 의하여 여러 가지 출력의 형광램프를 점등시킬 수 있는 시제품을 제작하였다. 이 가변출력형 전자식 안정기는 정류회로, 인버터회로, 그리고 여러 가지 출력의 램프에 이용되는 최적의 주파수를 결정하는 주파수 제어회로로 구성되어 있다. 제안된 설계방법의 적합성을 증명하기 의해 11[W], 15[W] 콤팩트 형광램프와 20[W] 형광램프에 적용하여 가변출력형 전자식 안정기의 시제품을 제작하였다. 램프의 전압과 전류를 관찰한 결과, PSpice 시뮬레이션 결과와 거의 일치하였다. 또한 발광효율은 다른 전자식 안정기와 거의 동일하였다. 그러므로 제안된 가변출력형 전자식 안정기의 설계 및 제어방법이 타당함을 입증하였다.

• 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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• 제11권2호
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• pp.135-141
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• 2006

본 논문은 단상 멀티레벨 인버터의 LC출력 필터 설계와 변조비에 따른 고조파 분석을 수행하였다. 일반적으로 고전력 응용에 적합한 멀티레벨 인버터는 낮은 스위칭 주파수하에서 구동되므로 출력단에 큰 고조파 성분을 포함하게 된다. 이를 감소시키기 위해 출력단에 필터를 삽입하는 방법이 효과적이다. 3레벨 NPC 멀티레벨 인버터의 출력단 고조파를 감소시키기 위한 필터 설계 방안을 검토하고, 디지털 제어 방식을 위해 DSP(TMS320C31)를 사용하였다. 또한 필터의 설계예시를 보였고, 설계된 시스템의 타당성을 시뮬레이션과 실험을 통해 입증하였다.

• Journal of international Conference on Electrical Machines and Systems
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• 제2권2호
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• pp.197-201
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• 2013

Cascaded H-bridge multilevel inverter requires independent DC voltage sources to produce multi output voltage levels. When it needs to generate more levels in the output voltage wave, the number of independent DC voltage sources usually limits its extension. To solve this problem, we propose a cascaded H-bridge multilevel inverter employing a front-end flyback converter for unifying input DC voltage sources. After theoretical analysis of the proposed circuit, we verify the validity of the proposed inverter using computer-aided simulations and experiments.