• Journal of Power Electronics
• /
• v.13 no.1
• /
• pp.31-39
• /
• 2013

The conventional non-isolated boost converter has some drawbacks such as poor dynamic performance and a discontinuous output current, which make it unsuitable for battery charging applications. In spite of its compactness and lightness, it is not preferred as a charger of portable electronic devices. In this paper, a non-isolated boost converter topology for Li-ion batteries suitable for fuel cell powered laptop computers is proposed and analyzed. The proposed converter has an additional inductor at the output to make a continuous output current. This feature makes it suitable for charger applications by eliminating the disadvantages of the conventional non-isolated boost converter mentioned above. A prototype of the proposed converter is built for the Li-ion battery charger of a laptop computer to prove the validity and advantages of the proposed topology.

• Proceedings of the KIPE Conference
• /
• 2012.07a
• /
• pp.177-178
• /
• 2012

In spite of its compactness and lightness, conventioan boost converter is not preferred for the charge applications. In this paper, a non-isolated boost converter topology for the Li-Ion battery suitable for fuel cell powered laptop computer is proposed and analyzed. The proposed converter has an additional inductor at the output to reduce the output ripple current and voltage. This feature makes it suitable for the charger application by eliminating the disadvantages of the conventional non-isolated boost converter mentioned above.

• Journal of Power Electronics
• /
• v.10 no.3
• /
• pp.235-244
• /
• 2010

This paper presents a new isolated soft-switching bidirectional buck-boost inverter for fuel cell applications. The buck-boost inverter combines an isolated DC-DC converter with a conventional inverter to implement buck-boost DC-DC and DC-AC conversion. The main switches achieve zero voltage switching and zero current switching by using a novel synchronous switching SVPWM and the volume of the transformer in the forward and fly-back mode is also minimized. This inverter is suitable for wide input voltage applications due to its high efficiency under all conditions. An active clamping circuit reduces the switch's spike voltage and regenerates the energy stored in the leakage inductance of the transformer; therefore, the overall efficiency is improved. This paper presents the operating principle, a theoretical analysis and design guidelines. Simulation and experimental results have validated the characteristics of the buck-boost inverter.

• Proceedings of the KIPE Conference
• /
• 2009.11a
• /
• pp.84-86
• /
• 2009

Isolated boost converter is desirable in the dc/dc converter applications where isolation is required and a large step up is needed. In this paper, it is proposed and analyzed the isolated boost converter which can step up low input voltage to high output voltage using transformer. Instead of using a conventional scheme, the proposed converter has the reset winding for volt-sec balance of transformer. Finally, the validity of the proposed isolated boost converter is verified by simulation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.24 no.6
• /
• pp.89-98
• /
• 2010

Isolated boost converter is desirable in the dc/dc converter applications where isolation is required and extremely high step up is needed. Transformer used to step up low input voltage into high output voltage must satisfy the volt-sec balance condition. Conventional isolated boost converter is controlled with conducting intervals overlapping. In this case, there is a problem that control circuit is complicated. In this paper, it is proposed and analyzed the isolated boost converter which set up a reset winding for the volt-sec balance of transformer and can construct the control circuit simple by using a self-driven switch. Finally, the validity of the theoretical analyses for the proposed converter is verified by both simulations and experiments on the 10[W] class isolated boost converter.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.20 no.5
• /
• pp.464-470
• /
• 2015

In this paper, a non-isolated three-level high step-up boost converter with output voltage balancing is proposed. By adding one extra inductor to the conventional three-level boost converter, the proposed converter is derived. Compared with the traditional boost converter and the three-level boost converter, the proposed converter can obtain very high voltage conversion ratio, and the voltage and current stress of switching devices and diodes are reduced. A 2.7 kW prototype converter is built and tested to verify performances of the proposed converter.

• Journal of Power Electronics
• /
• v.13 no.5
• /
• pp.766-778
• /
• 2013

The depletion of natural resources and renewable energy sources, such as photovoltaic (PV) energy, has been highlighted for global energy solution. The PV power control unit in the PV power-generation technology requires a high step-up DC-DC converter. The conventional step-up DC-DC converter has low efficiency and limited step-up ratio. To overcome these problems, a novel high step-up DC-DC converter using an isolated switched capacitor cell is proposed. The step-up converter uses the proposed transformer and employs the switched-capacitor cell to enable integration with the boost inductor. The output of the boost converter and isolated switched-capacitor cell are connected in series to obtain high step-up with low turn-on ratio. A hardware prototype with 30 V to 40 V input voltage and 340 V output voltage is implemented to verify the performance of the proposed converter. As an extended version, another novel high step-up isolated switched-capacitor single-ended DC-DC converter integrated with a tapped-inductor (TI) boost converter is proposed. The TI boost converter and isolated-switched-capacitor outputs are connected in series to achieve high step-up. All magnetic components are integrated in a single magnetic core to lower costs. A prototype hardware with 20 V to 40 V input voltage, 340 V output voltage, and 100 W output power is implemented to verify the performance of the proposed converter.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.24 no.5
• /
• pp.319-326
• /
• 2019

The use of high-voltage gain converters is essential for distributed power generation systems with renewable energy sources, such as fuel and solar cells, due to their low-voltage characteristics. In this study, a novel high-voltage gain non-isolated buck boost converter topology is proposed to cope with the need of a high-voltage conversion ratio without the transformer for the renewable energy sources. Given that the proposed topology utilizes the cascode structure, the voltage gain and the efficiency are higher than those of other conventional non-isolated converters. To demonstrate the feasibility of the proposed topology, the operation principle is presented, and the steady-state characteristics are analyzed in detail. The validity of the proposed converter is verified by experiments with a 400 W prototype converter.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.18 no.4
• /
• pp.342-348
• /
• 2013

In this paper, an improved non-isolated 3-level high step-up boost converter is proposed. By using the well known duality principle, the proposed converter is derived from two-phase buck converter. Compared with the traditional boost converter and 3-level boost converter, the proposed converter can obtain very high voltage conversion ratio and the voltage stress of switching devices and diodes is only 1/4 of the output voltage. A 1 kW prototype converter is built and tested to verify performances of the proposed converter.

• Proceedings of the KIPE Conference
• /
• 2010.07a
• /
• pp.481-482
• /
• 2010

In this paper, the isolated boost converter is designed by considering the current/voltage characteristics of the converter. Also, the validity of the design for the converter is verified by both simulations and experiments on the 10[W] class isolated boost converter.