• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.523-525
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• 2008

Novel zero-voltage switching(ZVS) dual inductor-fed DC-DC converter integrating a conventional dual inductor-fed boost converter(DIFBC) and a parallel bidirectional boost converter has been proposed. Most of current-fed type boost topologies including dual inductor schemes have crucial defects such as a high voltage spike on the main switch when it comes to turning off, an unattainable soft start-up due to the limited range of duty ratio, above 50%, and considerable switching losses due to the hard switching. By adding two auxiliary switches and an output capacitor on the conventional DIFBC, the proposed circuit can solve mentioned problems and improve the efficiency with simple methods. The operational principle and theoretical analysis of the proposed converter have been included. Experimental results based on a 42V input, 400V/1A output and 50kHz prototype are shown to verify the proposed scheme.

• Journal of Power Electronics
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• v.9 no.3
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• pp.430-437
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• 2009

This paper presents the dynamic characteristics of buck and buck-boost dc-dc converters with digital filters. At first, the PID, the minimum phase FIR filter and the IIR filter controls are discussed in the buck dc-dc converter. Comparisons of the dynamic characteristics between the buck and buck-boost converters are then discussed. As a result, it is clarified that the superior dynamic characteristics are realized in the IIR filter method. In the buck converter, the undershoot is less than 2% and the transient time is less than 0.4ms. On the other hand, in the buck-boost converter, the undershoot is about 3%. However, the transient time is approximately over 4ms because the output capacitance is too large to suppress the output voltage ripple in this type of converter.

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.3
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• pp.259-265
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• 2012

This paper introduces a method for design and implementation of a current controller for boost converter operating in continuous conduction mode (CCM) using a digital signal processor (DSP). A Proportional-Integral (PI) type current controller outputs an average voltage command for inductor, used in the input side of the boost converter, and the duty-ratio of PWM (pulse width modulation) signal for switching device is directly calculated from the average voltage command. The gains of the PI current controller are selected such that the current response characteristics are the same as those of a first-order low-pass filter. The proposed current control scheme is implemented using a DSP based on fixed-point math operations and an experimental study has been performed to validate the proposed method.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.530-533
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• 2001

Interleaved Dual Boost(IDB) converter can reduce current ripple, switching loss and harmonics without filter in input power line. Moreover, this improve power factor. In this paper, we will use the state average methode and small signal analysis at the Interleaved dual boost converter. 4-type controllers were designed by using control transfer function. The result of these controller simulations is analyzed and proposed a proper controller at IDB

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.3
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• pp.274-284
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• 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
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• v.14 no.1
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• pp.72-81
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• 2009

This paper presents quasi-resonant type high power factor ac power supply for atmospheric pressure plasma cleaning system adopting three phase PFC boost converter and it's control method. The presented ac power supply consists of single phase H-bridge inverter, step-up transformer for generating high voltage and three phase PFC boost converter for high power factor on source utility. Unlikely to the traditional LC resonant converter, the propose one has an inductor inside only. A single resonant takes place through the inside inductor and the capacitor from the plasma load modeled into two series capacitor and one resistance. The quasi-resonant can be achieved by cutting the switching signal when the load current decrease to zero. To obtain power control ability, the propose converter controlled by two control schemes. One is the changing output pulse period scheme in the manner of PFM(Pulse Frequency Modulation) control. On the other, to provide more higher power to load, the DC rail voltage is directly controlled by the 3-phase PFC boost converter. The significant merits of the proposed converter are the uniform power providing capability for high quality plasma generation and low reactive power in AC and DC side. The proposed work is verified through digital simulation and experimental implementation.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.5
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• pp.478-484
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• 2004

In this paper, two lossless snubber cells are proposed to generalize high frequency converter with losslless snubber. The selecting of snubber cells, which generalize high frequency converters, are depended on converter topologies. The cells have a saturable inductor, LC resonant tank and two diodes. In the cells, the saturable inductors extremely reduce resonant energy in the LC resonant tank. By minimizing resonant energy, the converter, which applies snubber cells, can operate at high frequency. These cells are applied for Buck, Boost, Buck-Boost, Cuk, ZETA, and SEPIC to generalize converter which have lossless snubber. The boost type converter has been implemented, with 400 kHz switching frequency for 125 W load to verify the converter characteristics.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.80-82
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• 2007

In this paper, we proposed new maximum electric power tracking algorithm by composing Buck-boost chopper circuit to charge electric power from wind energy generator which is under low and high wind velocity. The break function is also proposed with the existed buck-boost chopper switch. We made a proto-type as a lab level to verify appropriateness of using proposed circuit.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.11
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• pp.37-46
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• 2013

This paper proposes the boost type bidirectional zero current switching(ZCS) DC/DC converter of transformer series construction for electric vehicle operation using low voltage battery. This converter can high boost through the double voltage circuit and series construction of output part using two converters. This converter system has the advantages that bidirectional power transfer is excellent, size and making of transformer because of this converter keeps the transformation ratio to 1:1. Proposed DC/DC converter uses the ZCS method to decrease the switching loss. By replacing reactance ingredients of L-C resonance circuit for ZCS with leakage inductance ingredients of high frequency transformer and half-bridge capacitor it reduces system size and expense because of not add special reactor. It can confirm to output of high voltage to operate the electric vehicle with low voltage of input and operation of ZCS in all load region through the result of PSIM simulation and experiment.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.10
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• pp.59-68
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• 2013

This paper proposes the boost type bidirectional DC/DC converter with high efficiency for electric vehicle using an interleave method. This interleave method can reduce the system size because it reduces the ripple of output voltage and input current with no add to extra filter. Proposed system is consist of two converters and applies to interleaved method through phase shift to each converter. And it implements the high boost through voltage double and series construction of output port. Also, it reduces the price and increases the efficiency as operating the ZCS by leakage inductance of transformer and capacitor of voltage double with not add special reactor. Proposed DC/DC converter using interleave method is proved the validity through the result of PSIM simulation and experiment of 5kW DC/DC converter.