• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.178-181
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• 2005

This paper presents a synchronous rectifier in a LLC half bridge topology. The proposed synchronous rectifier is used to a current driven synchronous rectifier(SR). If FET is driven without dead times. Voltage driven synchronous rectifier may introduce voltage and current surge during the zero dead times. To solve this problem, we propose to use modified current driven synchronous rectifier. Finally, the prototype is built and comparison on the current and voltage driven synchronous rectifier(SR).

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.295-297
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• 2005

This paper presents a novel current driving method for the synchronous rectifier (SR) in a Flyback topology. The proposed current driven synchronous rectifier features low Power loss, good performance and the gate voltage of FET in the synchronous rectifier is easily controlled by zener voltage. The proposed SR driving method is implemented in a 200W Flyback converter with 400Vdc input and achieved excellent performance at full load.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1395-1397
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• 2005

This paper presents a novel current driving method for the synchronous rectifier(SR) in a flyback topology. The proposed current driven synchronous rectifier features low power loss, good performance and the gate voltage of FET in the synchronous rectifier is easily controlled by resistor ratio. The proposed SR driving method is implemented in a 200W Flyback converter with 400Vdc input and achieved excellent performance at full load.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권9호
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• pp.472-477
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• 2006

This paper presents a new voltage/current mixed method for driving synchronous rectifiers (SR) adapted to the flyback topology. The synchronous rectifier driven by the proposed voltage/current mixed method can operate at a wide load range with high efficiency. The gate voltage of MOSFET in the synchronous rectifier can be easily controlled by changing the ratio of resistors, irrespective of a line and load fluctuation. A 200W (12V/17A) prototype converter was built and an efficiency of 93% was measured at 10A load current.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.182-185
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• 2005

This paper presents a new voltage current driven method for the synchronous rectifier (SR) in a flyback topology. The proposed synchronous rectfier of voltage-current driven can operate at wide load range with high efficiency. The gate voltage of FET in the synchronous rectifier is easily controlled by resistor ratio. regardless of line and load fluctuation. The 200W (l2V/17A) prototype is built and achiveved efficiency as high as 90% at 4A, 93.2% at 7A and full load.

• Journal of Power Electronics
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• 제9권5호
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• pp.800-808
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• 2009

This paper presents a practical method of pressure control for a hydraulic oil-pump system using an SR (Switched Reluctance) drive. For a 6Mpa grade hydraulic oil-pump, a 2.6kW SR drive is developed. In order to get high performance pressure dynamics in actual applications, a data based PID control scheme is proposed. The look-up table from a pre-measured data base produces an approximate current reference based on motor speed and oil-pressure. A PID controller can compensate for the pressure error. With the combination of the two references, the proposed control scheme can achieve fast dynamics and stable operation. Furthermore, a suitable current controller considering the nonlinear characteristics of an SRM (Switched Reluctance Motor) and practical test methods for data measuring are presented. The proposed control scheme is verified by experimental tests.

• 조명전기설비학회논문지
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• 제30권1호
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• pp.79-86
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• 2016

In this paper, we propose a current-driven synchronous rectifier driver circuit for LLC resonant half-bridge converters. The proposed driver circuit detects a relatively low current in the primary side of the transformer although a large current is flowing in the secondary side. Due to this feature, the driver circuit has a simple circuit structure and stabilizes the switching operation with a logic-level switching voltages for the synchronous rectifier. The operation and performance of the proposed driver circuit are confirmed with a prototype of 1kW class LLC resonant half-bridge converter. The experimental results proved that the proposed synchronous rectifier driver method improves the power conversion efficiency by around 1% and reduces the internal power loss by 17W.

• Journal of Power Electronics
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• 제17권3호
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• pp.621-631
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• 2017

A KY converter integrated with a conventional synchronously rectified (SR) boost converter and a coupled inductor is presented in this paper. This improved KY converter has the following advantages: 1) the two converters use common switches; 2) the voltage gain of the KY converter can be improved due to the integration of a boost converter and a coupled inductor; 3) the leakage inductance of the coupled inductor is utilized to achieve zero voltage switching (ZVS); 4) the current stress on the charge pump capacitors and the decreasing rate of the diode current can be limited due to the use of the coupled inductor; and 5) the output current is non-pulsating. Moreover, the active switches are driven by using one half-bridge gate driver. Thus, no isolated driver is needed. Finally, the operating principle and analysis of the proposed converter are given to verify the effectiveness of the proposed converter.

• Journal of Power Electronics
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• 제14권2호
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• pp.217-225
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• 2014

This paper deals with the optimization of the driving techniques for the ZVT synchronous buck converter proposed in [1]. Two new gate drive circuits are proposed to allow this converter to operate by only one control signal as a 12V voltage regulator module (VRM). Voltage-driven method is applied for the synchronous rectifier. In addition, the control signal drives the main and auxiliary switches by one driving circuit. Both of the circuits are supplied by the input voltage. As a result, no supply voltage is required. This approach decreases both the complexity and cost in converter hardware implementation and is suitable for practical applications. In addition, the proposed SR driving scheme can also be used for many high frequency resonant converters and some high frequency discontinuous current mode PWM circuits. The ZVT synchronous buck converter with new gate drive circuits is analyzed and the presented experimental results confirm the theoretical analysis.

• Journal of Power Electronics
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• 제16권1호
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• pp.121-132
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• 2016

In this paper, high-efficiency design methodology of a zero-voltage-switching full-bridge (ZVS-FB) pulse width modulation (PWM) converter for server-computer power supply is discussed based on self-driven synchronous rectifier (SR) performance. The design approach focuses on rectifier conduction loss on the secondary side because of high output current application. Various-number parallel-connected SRs are evaluated to reduce high conduction loss. For this approach, the reliability of gate control signals produced from a self-driver is analyzed in detail to determine whether the converter achieves high efficiency. A laboratory prototype that operates at 80 kHz and rated 1 kW/12 V is built for various-number parallel combination of SRs to verify the proposed theoretical analysis and evaluations. Measurement results show that the best efficiency of the converter is 95.16%.