• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.669-672
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• 2005

Normally, the buck converter is used for the charging converter of photovoltaic generator because this converter has good characteristics compare with boost and buck-booster converter But, in case of the sollar-cell voltage is lower than charging voltage, we cannot charge the sollar energy to the charger. So, in this paper, we proposed the novel hybrid converter using by combination of buck and boost converter for the charging converter of photovoltaic generator, as a results, it can operate buck, boost and buck-boost mode. The proposed novel converter has the same characteristics of the existent buck converter and furthermore it can operate as a boost converter. So, we can make the more effective photovoltaic charging system.

• Journal of Electrical Engineering and Technology
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• v.11 no.6
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• pp.1684-1692
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• 2016

In order to adapt the fast dynamic performances of Buck DC/DC converter, and reduce the influence on converter performance owing to uncertain factors such as the disturbances of parameters and load, a control strategy based on two-dimensional hybrid cloud model is proposed. Firstly, two cloud models corresponding to the specific control inputs are determined by maximum determination approach, respectively, and then a control rule decided by the two cloud models is selected by a rule selector, finally, according to the reasoning structure of the rule, the control increment is calculated out by a two-dimensional hybrid cloud decision module. Both the simulation and experiment results show that the strategy can dramatically improve the dynamic performances of the converter, and enhance the adaptive ability to resist the random disturbances, and its control effect is superior to that of the current-mode control.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.551-554
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• 2006

An inverter system which consists of three bi-directional buck-boost converters, is proposed for motor driving. Three phase sinusoidal output voltages can be generated by utilizing three buck-boost converters. The advantage of this scheme is that it does not require a separate DC-DC converter for motor driving, i.e. inverter function is combined into the three DC-DC converters. This topology is suitable for inverters for hybrid or fuel cell vehicles where DC link voltage is subject to change depending upon charging status or output power. So the proposed system is capable of driving motor at high speed. The converter system is controlled by PI controller and simulation results done by MATLAB SIMULINK are provided.Ҙ?⨀ሉȀ̀㘰々K䍄乍?ጊ츀Ѐ㔹〻Ԁ䭃䑎䴀

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.4
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• pp.360-368
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• 2017

This paper proposes the 80-kW high-efficiency bidirectional hybrid SiC boost/buck converter using droop control for DC nano-grid. The proposed converter consists of four 20-kW modules to achieve fault tolerance, ease of thermal management, and reduced component stress. Each module is constructed as a cascaded structure of the two basic bi-directional converters, namely, interleaved boost and buck converters. A six-pack hybrid SiC intelligent power module (IPM) suitable for the proposed cascaded structure is adopted for high-efficiency and compactness. The proposed converter with hybrid switching method reduces the switching loss by minimizing switching of insulated gate bipolar transistor (IGBT). Each module control achieves smooth transfer from buck to boost operation and vice versa, since current controller switchover is not necessary. Furthermore, the proposed parallel control using DC droop with secondary control, enhances the current sharing accuracy while well regulating the DC bus voltage. A 20-kW prototype of the proposed converter has been developed and verified with experiments and indicates a 99.3% maximum efficiency and 98.8% rated efficiency.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.9
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• pp.1763-1770
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• 2016

This paper proposed hybrid converter to operate over a wide output load power. The switched-capacitor converter has a high efficiency at low load power and a low efficiency at high load power. On the contrary, the buck converter has a high efficiency at high load power and a low efficiency at low load power. The proposed hybrid converter has combination of the switched-capacitor converter and the buck converter. The switched-capacitor operates at low load power and buck converter operates at high load power, so that the hybrid converter is improved power efficiency at wide output load power. The hybrid converter was implemented with a $0.18{\mu}m$ CMOS process. The hybrid converter has a range of the load power between $50{\mu}W$and 100mW. The maximum power efficiencies are 93% and 77% at the buck converter and the switched-capacitor converter, respectively.

• Journal of Power Electronics
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• v.15 no.1
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• pp.31-38
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• 2015

In this paper, a buck-boost type battery charger is developed for charging battery set with a lower voltage. This battery charger is configured by a rectifier circuit, an integrated boost/buck power converter and a switched capacitors circuit. A boost power converter and a buck power converter sharing a common power electronic switch are integrated to form the integrated boost/buck power converter. By controlling the common power electronic switch, the battery charger performs a hybrid constant-current/constant-voltage charging method and gets a high input power factor. Accordingly, both the power circuit and the control circuit of the developed battery charger are simplified. The switched capacitors circuit is applied to be the output of the boost converter and the input of the buck converter. The switched capacitors circuit can change its voltage according to the utility voltage so as to reduce the step-up voltage gain of the boost converter when the utility voltage is small. Hence, the power efficiency of a buck-boost type battery charger can be improved. Moreover, the step-down voltage gain of the buck power converter is reduced to increase the controllable range of the duty ratio for the common power electronic switch. A prototype is developed and tested to verify the performance of the proposed battery charger.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.3
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• pp.56-61
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• 1996

In this paper, new buck converter of a TV power system is presented. First, we devised a revised driving circuit for an emitter-coupled type buck converter, by which it is possible to reduce the material cost of transformers and voltage stress of power device. Secondly, we adopted a hybrid oscillation technique. When TV system is in off-stage, initial standby power which is necessary for remote controllable TV system is supplied by self-oscillating mode. Main power which is necessry in TV system bing on state is provided by an externally triggered oscillating mode. The switching frequency is synchronized to the oscillating frequency of horizontal deflection in TV, by which we can reduce picture noises and the size of power transformer. Thirdly, a simple error amplifier is inserted to the feed-back loop to keep the output voltage constant which means pulse width modulatio mode is added in driving part of power device. Finally, we showed by experiments that our proposed converter performs well enough to be close to the theoretically predicted values.

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

• Journal of Electrical Engineering and Technology
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• v.7 no.5
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• pp.736-744
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• 2012

In this paper, a battery charging system for Plug-in Hybrid Electric Vehicle (PHEV) and Electric Vehicle (EV), and operation algorithm of charging system are introduced. Also, the proposed charging system uses commercial electricity in order to charge the battery of parked PHEV and 48V battery charging system with power factor controllable single phase converter for PHEV is investigated in this paper. This research verifies the power factor control of input and the converter output controlled by the charge control algorithm through simulation and experiment.

• Journal of Power Electronics
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• v.15 no.6
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• pp.1438-1445
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• 2015

A new DC-DC power converter is researched for renewable energy and battery hybrid power supplies systems in this paper. At the charging mode, a renewable energy source provides energy to charge a battery via the proposed converter. The operating principle of the proposed converter is the same as the conventional DC-DC buck converter. At the discharging mode, the battery releases its energy to the DC bus via the proposed converter. The proposed converter is a non-isolated high step-up DC-DC converter. The coupled-inductor technique is used to achieve a high step-up voltage gain by adjusting the turns ratio. Moreover, the leakage-inductor energies of the primary and secondary windings can be recycled. Thus, the conversion efficiency can be improved. Therefore, only one power converter is utilized at the charging or discharging modes. Finally, a prototype circuit is implemented to verify the performance of the proposed converter.