• Journal of Power Electronics
• /
• v.12 no.6
• /
• pp.912-924
• /
• 2012

In hybrid renewable power systems, the use of a multiple-input dc/dc converter (MIC) leads to simpler circuit and lower cost, when compared to the conventional use of several single-input converters. This paper proposed a novel three-input buck/boost/buck-boost converter, which can be used in applications with various values of input voltage. The energy sources in this converter can deliver power to the load either simultaneously or individually in one switching period. The steady relationship, the power management strategy and the small-signal circuit model of this converter have been derived. With decoupling technology, modeling and regulator design can be obtained under multi-loop control modes. Finally, three generating methods of a multiple-input buck/boost/buck-boost converter is given, and this method can be extended to the other multiple-input dc/dc converters.

• 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 Navigation and Port Research
• /
• v.31 no.10
• /
• pp.839-844
• /
• 2007

This paper describes the performance of DC-DC converters for buoy such as buck, boost, and buck-boost. The operating characteristic and charging efficiency with battery, which has a considerable properties about converters with PV(photovoltaic) system, is analyzed in this paper. It is performed by using the MPPT(Maximum Power Point Tracker) algorithm The basic equations of switching operation for converter are described, and the equations are analyzed with according to switch state. Whereas this analysis is directed toward the selection of converter for buoy, it also provides the insight into the behaviour of converter and performance of the proposed algorithm Finally, the suitable DC-DC converter is proposed for buoy, and the characteristic experiment is performed with the buck converter.

• Proceedings of the KIEE Conference
• /
• 1995.07a
• /
• pp.195-197
• /
• 1995

In this paper, for a constant switching frequency, the configuration and the control strategy of the resonant buck-boost type converter are proposed by the combination of zero voltage switching(ZVS) and zero current switching(ZCS) with PWM method. Also, in the configuration of power control circuit, transformer is not used in the viewpoint of economy. And the circuit has fewer power switching elements than a general resonant power converter, simulation results and experiments make show the advantages mentioned.

• Journal of Power Electronics
• /
• v.14 no.5
• /
• pp.899-907
• /
• 2014

This paper proposes a single-phase bidirectional AC/DC converter topology applied in V2G systems, which consists of an inverter and a bidirectional non-inverting buck-boost converter. This topology can operate in four modes: buck charging, boost charging, buck discharging and boost discharging with high input current quality and unity input power factor. The inverter switches at line frequency, which is different from conventional voltage source inverters. A bidirectional buck-boost converter is utilized to adapt to a wider charging voltage range. The modulation and control strategy is introduced in detail, and the switching patterns are optimized to reduce the current ripple. In addition, the semiconductor losses are analyzed. Simulation and experimental results demonstrate the validity and effectiveness of the proposed topology.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.2
• /
• pp.838-848
• /
• 2018

This paper proposes a single-phase buck-boost AC-AC converter. It consists of three legs with six switching units (each unit is composed of an active switch and a diode) and its input and output ports share a common ground. It can provide buck-boost voltage operation and immune from shoot-through problem. Since only two switching units are involved in the current paths, the conduction losses are low, which improves the system efficiency. The operation principle of the proposed circuit is firstly presented, and then, various operation conditions are introduced to achieve different output voltages with step-changed frequencies. Additionally, the parameters design and comparative analysis of the power losses are also given. Finally, experimental results verify the correctness of the proposed converter.

• Journal of Power Electronics
• /
• v.2 no.1
• /
• pp.46-54
• /
• 2002

In this paper a neural network controller for achieving maximum power tracking as well as output voltage regulation, for a wind energy conversion system (WECS) employing a permanent magnet synchronous generator is proposed. The permanent magnet generator (PMG) supplies a dc load via a bridge rectifier and two buck-boost converters. Adjusting the switching frequency of the first buck-boost converter achieves maximum power tracking. Adjusting the switching frequency of the second buck-boost converter allows output voltage regulation. The on-time of the switching devices of the two converters are supplied by the developed neural network (NN). The effect of sudden changes in wind speed and/ or in reference voltage on the performance of the NN controller are explored. Simulation results showed the possibility of achieving maximum power tracking and output voltage regulation simulation with the developed neural network controllers. The results proved also the fast response and robustness of the proposed control system.

• Proceedings of the KIPE Conference
• /
• 2001.10a
• /
• pp.656-659
• /
• 2001

In this paper a neural network controller for achieving maximum power tracking as well as output voltage regulation, for a wind energy conversion system(WECS) employing a permanent magnet synchronous generator, is proposed. The permanent magnet generator (PMG) supplies a dc load via a bridge rectifier and two buck-boost converters. Adjusting the switching frequency of the first buck-boost converter achieves maximum power tracking. Adjusting the switching frequency of the second buck-boost converter allows output voltage regulation. The on-times of the switching devices of the two converters are supplied by the developed neural network(NN). The effect of sudden changes in wind speed ,and/or in reference voltage on the performance of the NN controller are explored. Simulation results showed the possibility of achieving maximum power tracking and output voltage regulation simultaneously with the developed neural network controller. The results proved also the fast response and robustness of the proposed control system.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.19 no.6
• /
• pp.481-487
• /
• 2014

This study proposes a two-phase non-inverting buck-boost converter that uses a coupled inductor. The multi-phase converter has many advantages over single-phase counterparts, such as reduced output current ripple and conduction loss in switching devices and passive elements. Although the output current ripple of the multi-phase converter is reduced significantly because of the interleaved effect, the inductor current ripple is not reduced in multi-phase converters. One of the solutions to this problem is to use a coupled inductor. A 4 kW prototype converter is built and tested to verify the performance of the proposed converter.

• Proceedings of the KIEE Conference
• /
• 1994.07a
• /
• pp.512-515
• /
• 1994

This paper propose the high power factor and efficiency buck-boost AC-DC converter because the input current is made sinusoidal wave in single phase alternating current source. The proposed converter is able to minimize switching loss by the partial resonant switching which is for switching devices to operate the zero voltage switching (ZVS) or zero current switching(ZCS) without increasing their voltage and current stresses.