• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권7호
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• pp.356-363
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• 2001

A SRG (Switched Reluctance Generator) has many advantages such as high efficiency, low cost, high-speed capability and robustness compared with other of machine. But the control methods that have been adopted for SRGs are complicated. This paper proposes a simple control method using the PID controller which only controls turn-off angles while keeping turn-on angles of SRG constant. In order to keep the output voltage constant, the turn-off angle for load variations is controlled by using linearity between the generated current and turn-off angle since the reference generated current can be led through the voltage errors between the reference and the actual voltage. The suggested control method enhances the robustness of this system and simplifies the hardware and software by using only the voltage and the speed sensors. The proposed method is verified by experiments.

• 대한전기학회논문지
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• 제41권6호
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• pp.600-606
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• 1992

The series connection of power switching semiconductor elements is essential when a high voltage converter is made, so researches are being conducted to further develop this technology. In the series connection of power switching semiconductor elements, the main problem is that simultaneous conduction at turn-on and simultaneous blocking at turn-off together with voltage balancing are unattainable because of the difference of their switching characteristics. In this paper a novel series connection algorithm is proposed, which can implement not only the synchronization of the points of turn-on and turn-off time but the dynamic voltage balancing in spite of the difference of each switching characteristics. The proposed method is that the compensated control signal is attained from the voltage feedback signal and applied to the series-connected power transistors independently. Computer simulation and experimental results verify its validity.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.414-417
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• 2001

SRG (Switched Reluctance Generator) have many advantages such as high efficiency, low cost, high-speed capability and robustness compared with characteristics of other machines. However, the control methods that have been adopted for SRGs are complicated. This paper proposes a simple control method using PID controller that only controls turn-off angles while keeping turn-on angles of SRG constant. The linear characteristics between the generated current and the turn-off angle can be used to control the turn-off angle for load variations. Since the reference current for generation can be produced from an error between the reference and the real voltage, it can be controlled to keep the output voltage constant. The proposed control method enhances the robustness of this system and simplifies the hardware and software by using only the voltage and speed sensors. The proposed method is verified by experimental results.

• 한국전기전자재료학회논문지
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• 제19권12호
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• pp.1073-1077
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• 2006

Proton irradiation technology was used for improvement of switching characteristics of the PT-IGBT. Proton irradiation was carried out at 5.56 MeV energy with $1{\times}10^{12}/cm^2$ doze from the back side of the wafer. The I-V, breakdown voltage, and turn-off delay time of the device were analyzed and compared with those of un-irradiated device and e-beam irradiated device which was conventional method for minority carrier lifetime reduction. For proton irradiated device, the breakdown voltage and the on-state voltage were 733 V and 1.85 V which were originally 749 V and 1.25 V, respectively. The turn-off time has been reduced to 170 ns, which was originally $6{\mu}s$ for the un-irradiated device. The proton irradiated device was superior to e-beam irradiated device for the breakdown voltage and the on-state voltage which were 698 V and 1.95 V, respectively, nevertheless turn-off time of proton irradiated device was reduced to about 60 % compared to that of the e-beam irradiated device.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.22-23
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• 2006

Proton irradiation technology was used for improvement of switching characteristics of the PT-IGBT. Proton irradiation was carried out at 5.56 MeV energy with $1{\times}10^{12}/cm^2$ doze from the back side of the wafer. Characterization of the device was performed by I-V, breakdown voltage, threshold voltage, and turn-off delay time measurement. For irradiated device by 5.56 MeV energy, the breakdown voltage and the threshold voltage were 730 V and 6.5~6.6 V, respectively. The turn-off time has been reduced to 170 ns, which was original $6\;{\mu}s$ for the un-irradiated device.

• 전력전자학회논문지
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• 제22권2호
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• pp.181-184
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• 2017

This study analyzes the turn-on and turn-off transients of a metal-oxide-semiconductor field-effect transistor (MOSFET) with high-switching frequency systems. In these systems, the voltage distortion becomes serious at the output terminal of a Vienna rectifier by the turn-off delay of the MOSFET. The current has low-order harmonics through this voltage distortion. This paper describes the transient of the turn-off that causes the voltage distortion. The algorithm for reducing the sixth harmonic using a proportional-resonance controller is proposed to improve the current distortion without complex calculation for compensation. The reduction of the current distortion by high-switching frequency is verified by experiment with the 2.5-kW prototype Vienna rectifier.

• 전기학회논문지
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• 제57권8호
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• pp.1356-1361
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• 2008

A switched reluctance generator(SRG) has simple magnetic structure, and needs simple power electronic driving circuit. But, a SRG are no windings or permanent magnets on the rotor, and there are concentrated windings placed around each salient pole on the stator. Because of the characteristics of time-sharing excitation, the control of SRG is very flexible. And there are several parameters for controlling SRG, such as switch turn-on angle, switch turn-off angle, and exciting voltage and controlling mode, all these will affect the generation greatly. A SRG has positive torque at increasing inductance region and negative torque at decreasing inductance region. In this paper, we studied characteristics about the switch turn-on and off angles according to switch method for constant output voltage of the fixed speed SRG. It is the acoustic noise and torque ripple characteristics. Characteristics for a switch angle and method are presented by experiment using a 50W SRG with 12/8 poles.

• 대한전기학회논문지
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• 제43권2호
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• pp.244-250
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• 1994

This paper presents the design of a new turn-off gate drive circuit for GTO which can accomplish faster turn-off switching. The major disadvantage of the conventional turn-off gate drive technique is that it has a difficulty in realizing high negative diS1GQT/dt because of VS1RGM(maximum reverse gate voltage) and stray inductances of turn-off gate drive circuit[1~2]. The new trun-off gate drive technique can overcome this problem by adding another turn-off gate drive circuit to the conventional turn-off gate drive circuit. Simulation and experimental results of the new turn-off gate drive circuit in conjunction with chopper circuit verify a faster turn-off switching performance.

• 전기학회논문지P
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• 제53권3호
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• pp.148-151
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• 2004

For turn on high pressure sodium vapor lamp, Starting Voltage is very important factor. This starting voltage supply to high pressure sodium vapor lamp as electric discharge lamp, Electric field is producted in electric discharge tube, So accelerative electron collide against vapor atom and second electron is generated, And rapidly the current flow to electric discharge tube. This starting voltage is high voltage and source for melting contact that relay is according as turn on/off high pressure sodium vapor lamp. Consequently, This paper propose that the prevention of melting contact in accordance relay of controller for turn on/off high pressure sodium vapor lamp.

• Nuclear Engineering and Technology
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• 제55권9호
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• pp.3334-3341
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• 2023

We studied the irradiation effects of fast neutron generated by a 30 MeV cyclotron on the electrical and switching characteristics of NPT-IGBT devices. Fast neutron fluence ranges from 2.7 × 10⁹ to 1.82 × 10¹³ n/cm². Electrical characteristics of the IGBT device such as I-V, forward voltage drop and additionally switching characteristics of turn-on and -off were measured. As the neutron fluence increased, the device's threshold voltage decreased, the forward voltage drop increased significantly, and the turn-on and turn-off time became faster. In particular, the delay time of turn-on switching was improved by about 35% to a maximum of about 39.68 ns, and that of turn-off switching was also reduced by about 40%-84.89 ns, showing a faster switching.