• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.131-133
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• 2006

A high efficiency half bridge converter for PDP in whole operation load range is proposed in this paper. The ZVS(Zero Voltage Switching) in whole load range and high efficiency in low load range is achieved because the proposed converter is switched by fixed frequency asymmetrical duty ratio and resonant operation.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.510-513
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• 2001

In this paper, an application of asymmetrical duty control method to a boost input type active clamp DC-DC converter is discussed. In order to verify the discussed results, a 50W prototype converter is built and is tested. Through the experimental results an asymmetrical controlled boost input type active clamp converter is validated.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.2
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• pp.134-143
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• 2016

This paper proposes a novel asymmetrical interior permanent magnet (IPM) brushless DC (BLDC) motor structure, which utilizes half-type permanent magnet (PM) configuration and has asymmetrical side gaps (slot next to the PMs) for reducing torque ripples. This structure uses 24% less volume of PMs than conventional IPM BLDC motor with a full set of magnets. The characteristics of the proposed motor are compared with three other half-type IPM BLDC motors through finite elements method (FEM) analysis, and the usefulness of the proposed motor was verified through experimental evaluation on prototypes of the conventional motor and proposed motor under various torque load conditions. This research obtained a high-performance IPM BLDC motor while decreasing manufacturing cost at the same time.

• Journal of Power Electronics
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• v.15 no.2
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• pp.544-554
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• 2015

This paper presents a steady-state operation analysis of full-bridge series-resonant inverters focusing on the distorted load current due to low-quality-factor resonant circuits in induction heating and other applications. The regions of operation based on the zero-voltage switching (ZVS) and non-zero-voltage switching (NON-ZVS) operations of the asymmetrical voltage-cancellation control technique are identified. The effects of a distorted load current under a wide range of output powers are also analyzed for achieving a precise ZVS operating region. An experimental study is performed with a 1kW prototype. Simulation and experimental studies have confirmed the validity of the proposed method. An efficiency comparison between the variable frequency method and the conventional fixed-frequency method is provided.

• The Transactions of the Korean Institute of Power Electronics
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• v.2 no.3
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• pp.26-36
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• 1997

An single stage AC/DC converter based on half bridge topology suitable for low power level applications is proposed. The proposed converter has high power factor, low harmonic distortion, and tight output regulations. Asymmetrical control and synchronous rectification are adopted to reduce the switching loss and rectification loss, respectively. The modelling employing average modelling method and detailed analysis are performed to derive the design equations. According to these design equations, a prototype converter has been designed and experimented. This prototype meets the IEC 555-2 regulations with near unity power factor and high efficiency.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.237-240
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• 2000

A new control method using average comparison strategy have been proposed in this paper. This control method realizes sinusoidal input and output current. unity input displacement factor regardless of load power factor. Moreover compensation of the asymmetrical and harmonic containing input voltage is sautomatically realized and calculation time of control function is reduced.

• Bulletin of the Korean Chemical Society
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• v.27 no.3
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• pp.413-418
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• 2006

Sodium hyaluronate (NaHA), water soluble polymer having ultra-high molecular weight, is characterized by using on-line frit inlet asymmetrical flow field-flow fractionation (FI-AFlFFF) and multiangle light scattering (MALS). This study demonstrates the capability of power programming FI-AFlFFF for the separation of NaHA and the applicability of FI-AFlFFF with MALS for the characterization of molecular weight distribution and their structural information. Since sample injection and relaxation in FI-AFlFFF are achieved by using hydrodynamic relaxation, separation of high molecular weight polymers can be achieved smoothly without halting the separation flow. Experiments are carried out with the two different NaHA products (a raw NaHA sample and a thermally degraded NaHA product) and molecular weight distribution and conformations in solution are determined. Influence of sample filtration on the change of molecular weight distribution is also discussed.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.257-260
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• 2005

Three different current-mode control schemes, peak current-mode control, charge control, and average current-mode control, are investigated for applications to asymmetrical half-bridge dc-to-dc converters. The principles, implementation, and performance of the three control schemes are compared in an attempt to identify the irrespective merits and limitations. Design examples for feedback compensations are given for the three control schemes. A 50 W experimental asymmetrical half-bridge dc-to-dc converter was used to experimentally verify the theoretical results of the paper.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.271-279
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• 2015

Induction cooking application with multiple loads need high power inverters and appropriate control techniques. This paper proposes an inverter configuration with buck-boost converter for multiple load induction cooking application with independent control of each load. It uses one half-bridge for each load. For a given dc supply of $V_{DC}$, one more $V_{DC}$ is derived using buck-boost converter giving $2V_{DC}$ as the input to each half-bridge inverter. Series resonant loads are connected between the centre point of $2V_{DC}$ and each half-bridge. The output voltage across each load is like that of a full-bridge inverter. In the proposed configuration, half of the output power is supplied to each load directly from the source and remaining half of the output power is supplied to each load through buck-boost converter. With buck-boost converter, each half-bridge inverter output power is increased to a full-bridge inverter output power level. Each half-bridge is operated with constant and same switching frequency with asymmetrical duty cycle (ADC) control technique. By ADC, output power of each load is independently controlled. This configuration also offers reduced component count. The proposed inverter configuration is simulated and experimentally verified with two loads. Simulation and experimental results are in good agreement. This configuration can be extended to multiple loads.

• Journal of Electrical Engineering and Technology
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• v.6 no.3
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• pp.293-301
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• 2011

This paper presents a novel theoretical method based on power analysis to obtain voltage reference values for an inverter-based compensator. This type of compensator, which is installed in parallel with the load, is usually referred to as the active filter. The proposed method is tailored to design the compensator in such a way that it can simultaneously balance the asymmetric load, as well as correct the power factor of the supply side. For clarity, a static compensator is first considered and a recursive algorithm is utilized to calculate the reactance values. The algorithm is then extended to calculate voltage reference values when the compensator is inverter based. It is evident that the compensator would be asymmetric since the load is unbalanced. The salient feature associated with the proposed method is that the circuit representation of system load is not required and that the load is recognized just by its active and reactive consumptions. Hence, the type and connection of load do not matter. The validity and performance of the new approach are analyzed via a numerical example, and the obtained results are thoroughly discussed.