• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.5
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• pp.29-36
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• 2010

In this paper, we propose a single-phase inverter system using new modulation method. The proposed system is composed of a buck-boost converter and an inverter and controlled by PWAM scheme. PWAM method is a new modulation method which is the incorporation of PWM(Pulse Width Modulation) and PAM(Pulse Amplitude Modulation) methods. The DC voltage which is the input voltage of buck-boost converter is converted into a variable DC voltage by buck-boost converter. Also, the variable DC voltage which is the output voltage of buck-boost converter is converted into a sinusoidal AC voltage by inverter. The input voltage of inverter is processed by PWM switching in PWM section and bypassed in PAM section. By using PWAM method, switching action is not existed in PAM section and thus the times of switching is reduced. As a result, the switching loss can be reduced.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.8
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• pp.528-533
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• 1988

The miniturization of a DC-to-DC converter in connection with the stability is investigated in this paper. As both the capacitance of the smoothing capacitor and the inductance of the reactor are reduced by rasing the switching frequency, it is known that the stability of the buck converter declines with the switching frequency but the buck-boost converter has a nearly uniform stability. Furthermore, that the buck-boost converter is suitable for the miniturization of circuit is cleared in the high frequency region above a certain switching frequency.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.824-827
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• 1987

The miniturization of a DC-DC converter circuit in connection with the stability is investigated in this paper. As both the capacitance of the smoothing capacitor and the inductance of the reactor are reduced by raising the switching frequency, it is known that the stability of the buck converter declines with the switching frequency but the buck-boost converter has a nearly uniform stability. Furthermore, that in the frequency region above a certain switching frequency the buck-boost converter is suitable for the miniturization of circuit is cleared.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.2
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• pp.190-196
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• 2013

It presents a unification of buck-boost and flyback converter for driving a cascaded H-bridge multilevel inverter with a single independent DC voltage source. Cascaded H-bridge multilevel inverter is useful to make many output voltage levels for sinusoidal waveform by combining two or more H-bridge modules. However, each H-bridge module needs an independent DC voltage source to generate multi levels in an output voltage. This topological characteristic brings a demerit of increasing the number of independent DC voltage sources when it needs to increase the number of output voltage levels. To solve this problem, we propose a converter combining a buck-boost converter with a flyback converter. The proposed converter provides independent DC voltage sources at back-end two H-bridge modules. After analyzing theoretical operation of the circuit topology, the validity of the proposed approach is verified by computer-aided simulations using PSIM and experiments.

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

• Journal of Power Electronics
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• v.2 no.2
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• pp.139-145
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• 2002

Because conventional switching converters have been usually using unbalanced circuit topologies, parasitice between the drain/collertor of an active switch and frame ground through its heat sink may generate the commom-mode conducted noise. We have proposed a balanced switching converter circuit, whitch is an effective way to reduce the commom-mode converter version of the balanced switching converter was presented and the mechanism of the commom-mode noise reduction was explained using equivalent circuits. This paper extends the concept of the balanced switch converter circuit and presents a buck-boost converter version of the blanced switching converter. The feature of common-mode niose reduction is confirmed by experimental resuits and the mechanisem of the commom-mode niose reduction is explained using equivalent circuits.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.749-753
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• 2003

This paper presents an output voltage regulation system using PWM Buck-Boost AC-AC converter for power qualify improvement of custom power. This paper proposes dynamic modeling of the system for control object and in addition, a controller design example. Therefore, system state equation is derived whereby the transfer function could be obtained. The paper shows a regulation controller for tracking the output voltage to the reference under specific operating point. Finally, this paper shows validity and practical applicability of the proposed modelling and system design by experimental results.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.6
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• pp.465-471
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• 2007

The system efficiency of the proposed Buck-Boost AC-DC converter is increased by soft switching method. The converter includes to merit of power factor correction (PFC) from sinusoidal control of input current. The switching behavior of control switches operates with soft switching by partial resonance, and then the proposed converter has high system efficiency with decrement of switching power loss. The input current waveform in proposed converter is got to be a sinusoidal form of discontinuous quasi-pulse row in proportion to magnitude of AC input voltage under the constant duty cycle switching. Therefore, the input power factor is nearly unity. The output voltage of the converter is regulated by PWM control technique. The discontinuous mode action of current flowing into inductor makes to simplify control method and control components. The proposed PFC Buck-Boost converter is analyzed to compare with the conventional PFC Buck-Boost converter. Some computer simulative results and experimental results confirm to the validity of the analytical results.

• Journal of Electrical Engineering and Technology
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• v.6 no.4
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• pp.519-526
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• 2011

An investigation of the mechanism of period-doubling bifurcation in a voltage mode controlled buck-boost converter operating in discontinuous conduction mode is conducted from the viewpoint of nonlinear dynamical systems. The discrete iterative model describing the dynamics of the close-loop is derived. Period-doubling bifurcation occurs at certain values of the feedback factor. Results from numerical simulations and experiments are provided to verify the evolution of perioddoubling bifurcation, and the results are consistent with the theoretical analysis. These results show that the buck-boost converters exhibit a wide range of nonlinear behavior, and the system exhibits a typical period-doubling bifurcation route to chaos under particular operating conditions.

• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.151-153
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• 2007

In this paper, the control method of extracting maximum power from the seaflow energy is proposed. This system consists of buck-boost converter, bridge diode. The control is performed by using the variable duty ratio control of buck-boost converter. For extracting maximum power, it is necessary to know the seaflow turbine's maximum power curve and the seaflow speed measurement. But this makes the system difficult and expensive to implement. So this paper proposes the MPPT control method where the seaflow speed and the maximum power curve of the seaflow turbine are not required. The effectiveness of algorithm is simulated based on Matlab $Simulink^{(R)}$.