• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.8-10
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• 2005

In a general purpose inverter, a dead-time compensation strategy is very important for reducing torque ripples and acoustic noises of motors. However, in the case of small capacity inverter, the accurate dead-time compensation is hard to be obtained because a removal of the switching noise in a feedback current signal is difficult on condition of low-cost implementation. In this paper, the operation characteristics of the general purpose inverter applied the dead time compensation algorithm using an instantaneous back calculation of the phase angle of the current are presented.

• Journal of Power Electronics
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• 제17권1호
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• pp.115-126
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• 2017

This paper presents a new cascaded asymmetrical single phase multilevel converter with a reduced number of isolated DC sources and power semiconductor switches. The proposed inverter has only two H-bridges connected in cascade, one switching at a high frequency and the other switching at a low frequency. The Low Switching Frequency Inverter (LSFI) generates seven levels whereas the High Switching Frequency Inverter (HSFI) generates only two levels. This paper also presents a solution to the capacitor balancing issues of the LSFI. The proposed inverter has lot of advantages such as reductions in the number of DC sources, switching losses, power electronic devices, size and cost. The proposed inverter with a capacitor voltage balancing algorithm is simulated using MATLAB/SIMULINK. The switching logic of the proposed inverter with a capacitor voltage balancing algorithm is developed using a FPGA SPATRAN 3A DSP board. A laboratory prototype is built to validate the simulation results.

• 전력전자학회논문지
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• 제12권5호
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• pp.386-393
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• 2007

본 논문에서는 CIM(Current Injection Method)을 이용한 charge-pump방식의 plasma backlight용 고압 inverter회로를 제안한다. 고압 inverter에서 에너지 회수회로의 채용은 새로운 시도로서 에너지회수 이외에도 noise에 의한 시스템의 불안정성과 방전안정화에 기여하고 있다. charge-pump방식으로 스위치류의 내압을 저감하므로 cost면에서 매우 유리한 조건을 확립하였으며 CIM(Current Injection Method)방식의 적용으로 high speed 에너지 회수를 가능하게 하였다. 그리고 제안회로의 동작을 모드별로 해석하였으며, 실제 32" 패널에 적용하여 실험함으로써 제안한 회로의 유용성을 입증하였다.

• 제어로봇시스템학회논문지
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• 제10권5호
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• pp.411-414
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• 2004

In this paper, a power controller and 3 phase voltage source inverter are proposed for the improvement of weldability of large scaler Mash seam welder. The welder system is designed for the low cost and the improvement of weldability. For this system, the thyristor convertor has performed constant current controlling in the output terminal by using PAM type inverter. We have simulated our algorithm and made a prototype welder for experiment. Through the experiment, we have confirmed the improvement of weldability of our system.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 춘계학술대회
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• pp.117-122
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• 2005

This paper proposes an inverter for the grid-connected photovoltaic system based on the transformer-less inverter. This system consists of a high frequency converter bridge, high frequency transformer, diode bridge rectifiers, a DC filter, a low frequency inverter bridge, and an AC filter. The high frequency converter bridge switching at 20kHz is used to generate bipolar PWM pulse, and the high frequency transformer raise its voltage twice, which is subsequently rectified by diode bridge rectifiers to result in a full-wave rectified sine wave. Finally, it is unfolded by a low frequency inverter bridge to result in a 60Hz sine wave power output. Even though the high frequency link system needs more power semiconductors, a reduced size, light weight, and saved parts cost make this system more comparative than the other systems due to elimination of 60Hz transformer.

• Journal of Power Electronics
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• 제7권4호
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• pp.271-277
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• 2007

In this paper, an induction motor rotor fault diagnosis system using current signals, which are measured using the axis-transformation method is presented. Inverter-fed motor drives, unlike line-driven motor drives, have stator currents which are rich in harmonics and therefore fault diagnosis using stator current is not trivial. The current signals for rotor fault diagnosis need precise and high resolution information, which means the diagnosis system demands additional hardware such as a low pass filter, high resolution ADC, an encoder and additional hardware. Therefore, the proposed axis-transformation method is expected to contribute to a low cost fault diagnosis system in inverter-fed motor drives without the need for any additional hardware. In order to confirm the validity of the developed algorithms, various experiments for rotor faults are tested and the line current spectrum of each faulty situation, using the Park transformation, is compared with the results obtained from the FFT(Fast Fourier Transform).

• Journal of Power Electronics
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• 제12권5호
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• pp.699-707
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• 2012

This paper proposes a single-stage half-bridge electronic ballast with a high power factor using only a single coupled inductor. Compared to conventional high power factor electronic ballasts, the proposed ballast is a simpler circuit with a low cost and a high reliability. The proposed ballast is made up of a power-factor-correction (PFC) circuit and a self-oscillating class-D inverter. The PFC and inverter stages of the proposed ballast are simplified by sharing only a single coupled inductor and two common switches. The proposed PFC circuit can achieve a high power factor and low voltage stresses of the switches. A saturable transformer in the self-oscillating class-D inverter determines the switching frequency of the ballast. Experimental results obtained on a 30W fluorescent lamp are discussed.

• 전력전자학회논문지
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• 제19권4호
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• pp.376-382
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• 2014

This paper proposes the pulse width modulation (PWM) control strategy for low-speed operation in the three-level neutral-point-clamped (NPC) inverters based on the bootstrap gate drive circuit. As a purpose of the cost reduction, several papers have paid attention to the bootstrap circuit applied to the three-level NPC inverter. However, the bootstrap gate driver IC cannot generate the gate signal to the IGBT for low-speed operation, because the bootstrap capacitor voltage decreases under the threshold level. For low-speed operation, the dipolar and partial-dipolar modulations can be the effective solution. However, these modulations have drawbacks in terms of the switching loss and THD. Therefore, this paper proposes the PWM control strategy to operate the inverter at low-speed and to minimize the switching loss and harmonics. The experimental results are presented to verify the validity on the proposed method.

• 대한전기학회논문지
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• 제45권4호
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• pp.535-542
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• 1996

A zero voltage switching (ZVS) three level auxiliary resonant commutated pole inverter (ARCPI) is presented for high power GTO inverters. The concept of ARCP for two level inverter is extended to the three inverter. The proposed auxiliary commutation circuit consists of one resonant inductor and two bi-directional switches, which provides ZVS condition to the main devices without increasing device voltage or current stresses. The auxiliary device operates with zero current switching (ZCS) which enables use of the low cost thyristors. The proposed ARCPI can handle higher voltage and higher power (1-10MVA) comparing to the two level one. Operation and analysis of the ARCPI are illustrated and the features are compared o those of the snubber circuit incorporated three level inverter. Experimental results with 10kW, 4kHz prototype are presented to verify the principle of operation. (author). refs., figs., tab.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.456-459
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• 2000

Due to cost-effective and compact system design IPM-based inverters are now being seen as an attractive alternative to conventional discrete-based inverters technique for low power ac drives in particular such as washing machines refrigerators and air-conditioners. Fairchild-IPM newly developed in order to provide the advantages of the lowest cost and better performance is discussed and its specification is given.