• Journal of Power Electronics
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• 제11권5호
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• pp.719-725
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• 2011

This paper describes a novel Direct Torque Control (DTC) method for adjustable speed Doubly-Fed Induction Machine (DFIM) drives which is supplied by a two-level Space Vector Modulation (SVM) voltage source inverter (DTC-SVM) in the rotor circuit. The inverter reference voltage vector is obtained by using input-output feedback linearization control and a DFIM model in the stator a-b axes reference frame with stator currents and rotor fluxes as state variables. Moreover, to make this nonlinear controller stable and robust to most varying electrical parameter uncertainties, a two layer recurrent Artificial Neural Network (ANN) is used to estimate a certain function which shows the machine lumped uncertainty. The overall system stability is proved by the Lyapunov theorem. It is shown that the torque and flux tracking errors as well as the updated weights of the ANN are uniformly ultimately bounded. Finally, effectiveness of the proposed control approach is shown by computer simulation results.

• Proceedings of the KIEE Conference
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.1184-1186
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• 2002

Recently, according to the industrial development relative to multimedia, demand of display system is radically increase, thus development for power supply of back-lighting is advanced lively. Fluorescent lamp operated at high frequency by the electronic ballast provide benefits like unnoticeable flicker effect and higher luminous efficiency. This paper presents analysis of Push-Pull type resonant inverter for CCFL drive for stable characteristic and life improvement of fluorescent lamp operated at high frequency. Also it has proposed design procedure of Current-Fed type resonant inverter. On the basis of equivalent circuit, component characteristic and suitable region of operation frequency from simulation using Matlab and Pspice is predicted. Suitability of applied equivalent model and validity of design process from the experimental results with CCFL inverter.

• Proceedings of the KIPE Conference
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.69-74
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• 2001

In this Paper are described the indirect induction heated boiler and induction heated hot air producer using the voltage-fed series resonant high-frequency inverter which can operate in the frequency range from 20kHz to 50kHz. A specially designed induction heater, which is composed of laminated stainless assembly with many tiny holes and interconnected spot welding points between stainless plates, is inserted into the ceramic type vessel with external working coil. This working coil is connected to the inverter and turbulence fluid through this induction heater to moving fluid generates in the vessel. The operating performances of this unique appliance in next generation and its effectiveness are evaluated and discussed from a practical point of view.

• Proceedings of the KIEE Conference
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.537-540
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• 1991

This paper discusses with a voltage - fed Type high frequency inverter with simple main circuit and high efficiency. The proposed inverter is proper as a high frequency inverter of home applications applied with induction healing principle of high frequency. Further, its operating characteristics necessary to its design is estimated by analysis of a lumped circuit of heating system as a model.

• Journal of Power Electronics
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• 제18권4호
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• pp.1067-1074
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• 2018

This paper presents a control method for variable-speed motor drives that do not use a DC-link electrolytic capacitor. The proposed circuit consists of a power factor correction converter for boosting the DC-link voltage, an inverter for driving the motor, and a small DC-link film capacitor. By employing a small DC-link capacitor, the proposed circuit that is small, and a low cost and weight are achieved. However, because the DC-link voltage varies periodically, the control of the circuit is more difficult than that of the conventional method. Using the proposed control method, an inverter can be controlled reliably even when the capacitance of the DC-link capacitor is very small. Experiments are performed using a 1.5-kW inverter with a $20-{\mu}F$ DC-link capacitor, and the experimental results are analyzed thoroughly.

• Proceedings of the KIEE Conference
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.695-698
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• 1992

When the inverter driven Induction motor is compared with sinusoidal voltage driving, the loss is increased and efficiency in the same output is decreased by the time harmonics in inverter output. These are based on the eddy current on stator and the skin effects of rotor bar current induced from time harmonic. The aim of this paper is to estimate the equivalent circuit parameter of squirrel cage induction motor fed from inverter considering this effects.

• Journal of Electrical Engineering and Technology
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• 제8권5호
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• pp.1107-1115
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• 2013

A new PWM technique for a two-phase BLDC motor fed by a two-phase eight-switch inverter is proposed in this paper. It is well known that a two-phase eight-switch inverter can significantly improve power output compared with a two-phase six-switch inverter in a two-phase motor drive. To drive the two-phase BLDC motor simply and effectively, two normal PWM strategies are investigated to manage speed regulation. However, under the conditions of low speed and light load, especially during the braking process, the current in a short time of one period is near zero, which is a discontinuous waveform every half period. To solve it, a novel PWM technique is investigated to improve the operational performance of normal technique. Using the new PWM scheme, the current continues every half period and the braking performance is improved. The effectiveness of the proposed PWM method is verified through the experiments.

• Proceedings of the KIEE Conference
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.296-298
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• 1995

This paper proposes a new filter topology that suppresses the high voltage gradient(dv/dt) in ac motor terminals. The high voltage gradient(dv/dt) causes over voltages on the motor windings, the degradation or motor insulation, and the bearing failure. Moreover surge voltage with high voltage gradient(dv/dt) in the PWM inverter red drive system where long line cables are required causes more serious problem to the motor. Thus, the most advisable method is attaching output filter to the inverter output terminals. The conventional output filters have several problems such as bulky size, difficulty or parameter tuning. The proposed filter can be relatively smaller than the conventional filters. By the proposed filter, the shaping or PWM waveform can considerably suppress high dv/dt in motor feeding cable from the inverter. The effectiveness or the proposed filter is compared with that or the conventional one and is verified by the computer simulation.

• Proceedings of the KIEE Conference
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.711-713
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• 2000

Recently, the insulation breakdown accident happened at 6.6kV inverter driving motor brings out the reliability decrease to the motor driving system. We need to find the solution with system engineering level. The objectives of this study are developing the appropriate filter for the drive to protect the motor and the insulation system of motor which is driven by inverter. The circuit parameters of cable are calculated by EMTP(Electromagnetic Transient Program) to simulate the system. And we use MATLAB to find the appropriate filter parameter. The simulation and the test results are compared to verify the suitability of the filter parameter. We clarify the cause of the deterioration of the inverter driving motor through the analysis of insulation breakdown accidents. The endurance test scheme and the configuration method of insulation system are established.

• Proceedings of the KIEE Conference
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.1130-1132
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• 2000

In this paper, For Control of the speed sensorless induction motor propose the method which is controled the motor by operating two axis current in input current of the inverter. This method determines frequency of inverter in order to stator electromotive force and E/F ratio for the setting magnetic flux, drives for speed control using a voltage power converter of the induction motor by means of voltage fed converter with current control ability.