• The Transactions of the Korean Institute of Power Electronics
• /
• v.24 no.5
• /
• pp.372-378
• /
• 2019

This study proposes a new zero-current-zero-voltage-transition (ZCZVT) boost-flyback converter using a soft switching auxiliary circuit. The proposed converter integrates the boost and flyback converters to increase the voltage with a low duty ratio. The main and auxiliary switches turn the ZCZVT conditions on and off. Thus, the proposed converter has high efficiency. The voltage gain at the steady state is derived, and the inductor volt-second balance and the design guidelines are presented. Finally, the performance of the proposed converter is validated by experimental results from a 200 W, 30 V DC input, 400 V DC output, and 200 kHz boost-flyback converter prototype.

• Journal of Power Electronics
• /
• v.19 no.2
• /
• pp.549-559
• /
• 2019

This paper proposes an adaptive sliding mode control (ASMC) strategy with an enhanced optimal reaching law (EORL) for the robust current tracking control of the boost converter based hybrid power source (HPS) in an electric vehicle (EV). A conventional ASMC strategy based on state observers and the hysteresis control method is used to realize the current tracking control for the boost converter based HPS. Then a novel enhanced exponential reaching law is proposed to improve the ASMC. Moreover, an enhanced exponential reaching law is optimized by particle swarm optimization. Finally, the adaptive control factor is redesigned based on the EORL. Simulations and experiments are established to validate the ASMC strategy with the EORL. Results show that the ASMC strategy with the EORL has an excellent current tracking control effect for the boost converter based HPS. When compared with the conventional ASMC strategy, the convergence time of the ASMC strategy with the EORL can be effectively improved. In EV applications, the ASMC strategy with the EORL can achieve robust current tracking control of the boost converter based HPS. It can guarantee the active and stable power distribution for boost converter based HPS.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.26 no.3
• /
• pp.31-39
• /
• 2012

This paper presents a high efficiency coupled inductor boost DC-DC converter that uses a simple clamp circuit and the coupled inductor and thus overcomes output voltage limit of the conventional boost converter. The proposed converter solves problems of voltage stress of the power semiconductor switch and reverse recovery of the output diode using a simple clamp circuit composed of a diode and a capacitor, and thus the converter improves its total efficiency. In this paper, the operational principle of the proposed converter is explained by each mode and then a design example for the prototype converter based on the explanation is shown. And good performance of the proposed converter is verified through experimental results of the prototype converter that is implemented with the designed circuit parameters.

• Proceedings of the KIEE Conference
• /
• 2005.07b
• /
• pp.1428-1431
• /
• 2005

This paper presents an improved ZVT(Zero Voltage Transition) DC/DC Boost Converter using Active Snubber. The Conventional ZVT PWM Boost Converter is improved to minimize the switching loss of auxiliary switch using the minimum number of the components. In this thesis, advantage and disadvantages of Conventional ZVT Converter using a auxiliary resonant circuit is discussed. Then Improved ZVT soft switching converter will be discussed. In comparison a previous ZVT converter, the proposed converter reduces turn-off switching loss of the auxiliary switch. Therefore, the proposed converter has a high efficiency by active snubber. To show the superiority of this converter is verified through the experiment with a 640W, 100kHz prototype converter.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.8 no.3
• /
• pp.274-284
• /
• 2003

Multi-level converter that is high-capacity electric power conversion system is used widely to electric motor drive system and FATCs(Flexible AC Transmission Systems). H-Bridge converter has been prevalently applied to shunt-type system because it can be easily expanded to the multi-level. In steady states, converter is normally operated in the range of 0.7∼0.8 of modulation Index. Even though zero vectors are not imposed to high modulation index, DC-Link voltage Is constant. It means that converter has another boost vector except for zero vectors among several vectors in 3-level converter. This paper has examined the principle of boost vector and investigated the difference between another boost vector and zero vectors in 3-level converter. In addition, this paper has analysed and compared the charging currents and the capacitor voltages of two topologies. The currents and voltages are related to reference voltage. Therefore, it proposed the calculation method for the voltage ripple and the charging current of each capacitor and compared various DC-Link voltage control methods through the simulation.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.19 no.2
• /
• pp.157-163
• /
• 2014

This paper proposes a two-stage step-down buck and a tapped-inductor boost cascaded converter for high efficiency photovoltaic micro-inverter applications. The proposed inverter is a new structure to inject a rectified sinusoidal current into a low-frequency switching inverter for single-phase grid with unity power factor. To build a rectified-waveform of the output current. the converter employs both of a high efficiency step-up and a step-down converter in cascade. In step-down mode, tapped inductor(TI) boost converter stops and the buck converter operates alone. In boost mode, the TI converter operates with the halt of buck operation. The converter provides a rectified current to low frequency inverter, then the inverter converts the current into a unity power-factor sinusoidal waveform. By applying a TI, the converter can decrease the turn-on ratios of the main switch in TI boost converter even with an extreme step-up operation. The performance validation of the proposed design is confirmed by an experimental results of a 120W hardware prototype.

• Journal of the Korean Society of Industry Convergence
• /
• v.20 no.2
• /
• pp.97-104
• /
• 2017

In the present industrial field, the demand for the development of the solar power source device and the charging device for the solar cell is gradually increasing. The solar charger is largely divided into a DC-DC converter that converts the voltage generated from the sunlight to a charging voltage, and a battery and a charger that are charged with an actual battery. The conventional charger topology is used either as a Buck converter or a Boost converter alone, which has the disadvantage that the battery can not always be charged to the desired maximum power as input and output conditions change. Although studies using a topology capable of boosting and stepping have been carried out, Buck-Boost converters or Sepic converters with relatively low efficiency have been used. In this paper, we propose a new Buck Boost combination power converter topology structure that can use Buck converter and Boost converter at the same time to improve inductor current ripple and power converter efficiency caused by wide voltage control range like solar charger.

• Proceedings of the KIPE Conference
• /
• 2008.06a
• /
• pp.133-135
• /
• 2008

본 논문은 계통연계형 연료전지 PCS(Power Conditioning System)에서 최적의 승압효율을 갖는 Boost Converter의 설계를 위해 Boost Converter내의 각 소자의 선정에 따른 손실 및 분석을 통하여 최적의 소자선정 방법의 이해를 목적으로 한다. Boost Converter의 설계를 위한 소자선정을 위해 Or-CAD 16.0의 PSPICE Simulator을 사용하여 그 결과를 확인하였다.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.55 no.8
• /
• pp.423-429
• /
• 2006

Recently, the high frequency isolated boost DC/DC converter has been widely used for the PCS (Power Conditioning System) system because of its small size and low cost. However, the high frequency isolated boost DC/DC converters applied the conventional voltage-fed converter and current-fed converter have the problems such as the high conduction losses and the surge voltage due to the high circulating current and the leakage inductance, respectively. To overcome this problems, in this paper the secondary LLC resonant converter is proposed, and the experimental results of the secondary LLC series resonant converter for boost DC/DC converter are verified on the simulation based on the theoretical analysis and the 700W experimental prototype.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.3
• /
• pp.538-543
• /
• 2011

In this paper, design and control of an interleaved boost converter for multi-string PV Inverter are discussed. Interleaved Boost converter can reduce current ripples at input and output side by cancelling an each phase of inductor currents. Therefore, it contributes to increase efficiency and downsize the whole system volume, cost. One of the advantages of the multi-string system is easy to expand power capacity by connecting the converter modules in parallel. In order to reduce current ripples, the inductor currents on each phase are controlled independently in the converter module, and communication between the converter modules is required for further ripple current reduction. Current control algorithm for the balance of the each phase ripple currents and synchronization of the converter modules based on communication are proposed and implemented in the DSP programming. 10kW prototype of the multi-string converter module is assembled and experimental results are presented to verify the proposed ripple current reduction methods.