• Journal of Electrical Engineering and Technology
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• 제4권2호
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• pp.266-271
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• 2009

In this paper, improved direct torque control(DTC) of five-phase induction motor(IM) is proposed. Due to the additional degrees of freedom, five-phase IM drives present unique characteristics. One of them is the ability of enhancing the torque producing capability of the motor. Also five-phase motor drives possess many others advantage compared with the traditional three-phase motor drives. Such as, reducing the amplitude and increasing of frequency of torque pulsation, reducing amplitude of current per phase without increasing the voltage per phase and increasing the reliability. The direct torque control method is advantageous when it is applied to the five-phase IM. Because the five-phase inverter provides 32 space vectors in comparison to 8 space voltage vectors by the three-phase inverter. The 32 space voltage vectors are divided into three groups according to their magnitudes. The characteristics and dynamic performance of traditional five-phase DTC are analyzed and new DTC for five-phase IM is proposed. Therefore, a more precise flux and torque control algorithm for the five-phase IM drives can be suggested and explained. For presenting the superior performance of the pro-posed direct torque control, experimental results is presented using a 32 bit fixed point TMS320F2812 digital signal processor

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.673-676
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• 2001

The photovoltaic power generation system has a great future as clean energy instead of fossil fuel, which has many environmental problems such as exhausted gas or air pollution. In a utility interactive photovoltaic generation system, a three phase inverter is used for the connection between the photovoltaic array and the utility. This paper presents a three phase inverter for photovoltaic power system with current controller, voltage controller, PLL control system and the phase detector of interactive voltage by using dq transformation. The proposed inverter system provides a sinusoidal ac current for domestic loads and the utility line with unity power factor.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.334-336
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• 2001

The photovoltaic power generation system has a great future as clean energy instead of fossil fuel which has many environmental problems such as exhausted gas or air pollution. In a utility interactive photovoltaic generation system, a three-phase inverter is used for the connection between the photovoltaic array and the utility. This paper presents a three phase inverter for photovoltaic power system with current controller, voltage controller PLL control system and the phase detector of interactive voltage by using do transformation. The proposed inverter system provides a sinusoidal are current for domestic loads and the utility line with unity power factor. The results of the operated from January to October show the system characteristics.

• Journal of Power Electronics
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• 제11권5호
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• pp.677-687
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• 2011

In this paper a cycloconverter-type high frequency transformer link inverter with a reduced switch count is analyzed and designed. The proposed topology consists of an H-bridge inverter at the transformer's primary side and a cycloconverter with three bidirectional switches at the secondary. All of the switches of the cycloconverter operate in non-resonant zero voltage and zero current switching modes. To overcome a high voltage surge problem resulting from the transformer leakage inductance, phase angle control based on natural commutation is employed. The effectiveness of the proposed inverter is verified by constructing s 750W prototype. Experimentally, the inverter is able to supply a near sinusoidal output voltage with a total harmonic distortion of less than 1%. For comparison, a PSpice simulation of the inverter is also carried out. It was found that the experimental results are in very close agreement with the simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.543-545
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• 1996

In this paper, a voltage and current control scheme of a three-phase voltage source inverter for UPS is described. The inverter provides pure sinusoidal output voltage with very low THD(Total Harmonic Distortion). The proposed controller is designed to robust against the load change, parameter variations, and disturbances using PI controller. The switching pattern is determined to Space Vector Modulation. Finally, the performance of the proposed inverter is shown and discussed by simulation.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권2호
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• pp.89-96
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• 1999

This paper proposes a common-mode voltage reduction method base on SVPWM(Space-Vector Pulsewidth Modulation) in three phase PWM converter/inverter system. By shifting the active voltage vector of inverter and aligning this to the active vector of converter, it is possible to eliminate a common-mode voltage pulse in one control period. Since the proposed PWM method maintains the active voltage vector, it does not affect the control performance of PWM converter/inverter system. Without any extra hardware, overall common mode voltage dv/dt and conrresponding leakage current can be reduced to two-third of the conventional three phase symmetric SVPWM scheme.

• Journal of Electrical Engineering and Technology
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• 제5권2호
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• pp.290-298
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• 2010

This paper proposes an adaptive carrier-based pulse width modulation (PWM) method for a four-switch three-phase (4S3P) inverter under dc-link voltage ripple conditions. The proposed method guarantees balanced output currents despite of the existence of the voltage oscillations across two dc-link capacitors. And also, this new approach achieves a linear over-modulation with calculation time reduction. Simulation and experimental results are given to validate the feasibility of the proposed method.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 1990년도 추계학술발표회논문집
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• pp.68-72
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• 1990

In this paper, the technique of particul-ar harmonics elimination in three-phase PWM Inverter is discussed. And voltage control technique is derived whereby harmonics eli-mination is possible in variable voltage variable frequency three-phase I.M. The results show that experiments are in a good agreement with simulation based on the theory.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.260-265
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• 1999

This paper describes a novel control method of a three-phase PWM inverter for uninterruptible power supply(UPS) applications. To obtain the fast dynamics and excellent harmonic characteristics, a new state feedback control technique is proposed. The proposed control consists of the inner-loop current and outer-loop voltage controllers with a load current estimator to reduce the effects of the load variations and nonlinearity. In order to verify the effectiveness of the proposed control, the simulation is carried out for various load condition.

• 대한전기학회논문지
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• 제41권9호
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• pp.1031-1041
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• 1992

Existing current-controlled inverters with hysteresis controller (HC) result in the dependence of the inverter on its load characteristics, poor inverter utilization due to too much or too little supply voltage, and the current error in the hysteresis band(HB) which causes deterioration of operation of the supplied motor. In this paper, techniques and results of modeling the operation of current-controlled three phase power inverter with HC are presented. Four symmetrical control schemes are considered: the so called three independent control, three semi-dependent control(a), three semi-dependent control(b) and three dependent control each using three current controller. The dependence of the inverter on its load has been studied. To overcome this difficulty, an inner feedback control has been introduced and optimum parameter has been determined. With the addition of an inner feedback control, adjustment of the switching frequency to a desired value is possible. Also, this modification improves operating characteristics of inverter by enforcing a switching pattern of low dependence on the load, resulting in significantly improved quality of the output current.