• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.27 no.3
• /
• pp.55-64
• /
• 2013

In this paper, a new topology which can add a small reactor in series to a condenser-bank type reactive power compensator to limit current is proposed. And also the proposed topology can add or remove a power condenser safely without any addition of inrush-current suppression resistance. The proposed method tests variable resistance of the drain source of a switching device which is controlled by gate voltage in a two-way switch with a diode rectifier and FET switch. In other words, the proposed method is a inrush-current suppression method with the structure of variable resistance. In particular, the proposed method creates smooth current without any resonance in inrush-current as well as is not limited by the time of switch on and off.

• Journal of Power Electronics
• /
• v.10 no.6
• /
• pp.628-634
• /
• 2010

The paper describes aspects regarding an E-learning approach of resonant ac inverters. The learning process is based on "Learning by Doing" paradigm supported by several learning tools: electronic course materials, interactive simulation, laboratory plants and real experiments accessed by Web Publishing Tools under LabVIEW. Built on LabVIEW and accompanied by a robust, flexible and versatile hardware, the experiment allows a comprehensive study by remote controlling and performing real measurements on the inverters. The study is offered in a gradual manner, according to the Leonardo da Vinci project EDIPE ($\b{E}$-learning $\b{D}$istance $\b{I}$nteractive $\b{P}$ractical $\b{E}$ducation) philosophy: theoretical aspects followed by simulations, while in the end the real experiments are investigated. Studying and experimenting access is opened for 24 hours a day, 7 days a week under the Moodle booking system.

• Journal of Power Electronics
• /
• v.18 no.1
• /
• pp.81-91
• /
• 2018

This paper proposes a double line voltage synthesis (DLVS) strategy for three-to-five phase direct matrix converters. In the proposed strategy, the input and expected output voltages are divided into 6 segments and 10 segments, respectively. In addition, in order to obtain the maximum voltage transfer ratio (VTR), the input line voltages and "source key" should be selected reasonably according to different combinations of input and output segments. Then, the corresponding duty ratios are calculated to determine the switch sequences in different segment combinations. The output voltages and currents are still sinusoidal and symmetrical with little lower order harmonics under unbalanced or distorted input voltages by using this strategy. In addition, the common mode voltage (CMV) can be suppressed by rearranging some of the switching states. This strategy is analyzed and studied by a simulation model established in MATLAB/Simulink and an experimental platform, which is controlled by a DSP and FPGA. Simulation and experimental results verify the feasibility and validity of the proposed DLVS strategy.

• Proceedings of the KIEE Conference
• /
• 1993.07b
• /
• pp.908-911
• /
• 1993

The single-Phase induction motor is widely used in many light duty applications. especially in home and the office. At present, many applications which use these motor require continuously adjustable speed control. In the general, the speed control of single-phase induction motor is accomplished at a few discrete speeds by using tapped-windings, pole switching or gear. These techniques is inefficient and complicated. In this paper, auxiliary winding voltage phase angle of single-phase induction motor is used to continuously adjust electromagnetic torque. The analysis includes the determination of the relationship between the auauxiliary winding voltage phase angle and torque. Simulation results of the motor's torque-speed characteristics using the controlled auxiliary winding supply are shown and discussed. The drive is tested using a dynamometer to experimentally verify the results of the theory and simulations.

• Proceedings of the KIEE Conference
• /
• 2005.07b
• /
• pp.1534-1536
• /
• 2005

A DC-DC converter is being widely used for various household appliances and for industry applications. The DC-DC converter is powered from single battery, and the voltage is varied according to the purpose. In the vehicle, various accessories whose electric power is different are being used. Thus, plural number of DC-DC converter should be provided, so these situations bring complicated circuits, and accordingly, higher cost. Under such backgrounds, in this paper, we propose a novel buck-boost chopper circuit with simply configuration which can supply to two or more different output loads. The propose chewer circuit can control output voltages by controlling duty ratio by using typically two switching devices, which is composed by single boost-switch and single buck-switch. The output voltage can be controlled widely. A few modified circuits developed from the fundamental circuit are represented including the general multi-load circuit. And all this merits and appropriateness was proved by computer simulation and experience.

• Journal of Power Electronics
• /
• v.17 no.4
• /
• pp.1117-1126
• /
• 2017

The main contribution of this paper is the use of sensorless active diodes to generate the gate signals for a three-phase boost-rectifier with a self-powered control scheme. The sensorless operation is achieved making use of the gate control signals generated by the active diode schemes on each of the switching devices using a pulse width half-controlled boost rectifier modulation technique (PWM-HCBR). The proposed scheme synchronizes the gate control signals with a three phase voltage supply. Autonomous operation is obtained making use of the output DC bus to feed the control circuitry, the active diodes and the driver circuitry. The three-phase boost-rectifier is supplied by a three-phase permanent magnet electric generator powered by a solar concentrator dish with variable voltage and variable frequency conditions. Experimental results report an efficiency of up to 94.6% for 25 W and an input of 3.6 V peak per phase with 450.

• Advances in robotics research
• /
• v.1 no.1
• /
• pp.101-126
• /
• 2014

In this article we present modular neural control for a leg-wheel hybrid robot consisting of three legs with omnidirectional wheels. This neural control has four main modules having their functional origin in biological neural systems. A minimal recurrent control (MRC) module is for sensory signal processing and state memorization. Its outputs drive two front wheels while the rear wheel is controlled through a velocity regulating network (VRN) module. In parallel, a neural oscillator network module serves as a central pattern generator (CPG) controls leg movements for sidestepping. Stepping directions are achieved by a phase switching network (PSN) module. The combination of these modules generates various locomotion patterns and a reactive obstacle avoidance behavior. The behavior is driven by sensor inputs, to which additional neural preprocessing networks are applied. The complete neural circuitry is developed and tested using a physics simulation environment. This study verifies that the neural modules can serve a general purpose regardless of the robot's specific embodiment. We also believe that our neural modules can be important components for locomotion generation in other complex robotic systems or they can serve as useful modules for other module-based neural control applications.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.14 no.1
• /
• pp.81-86
• /
• 2019

This paper is concerned with a system design that enables a the plurality of switching mode power supplies to be supplied with larger power through a parallel connection. For this purpose, a shunt resistor is placed in series at the output of the constant voltage regulator and the output voltage is sensed and controlled using an arduino. In this paper, two constant-voltage regulators were used for the experiment, but it is possible to generalize for more boards. By using the method that controls the system, the sum of the currents delivered by the two systems to the load was found to be 96% of the current drawn from each board. In case of efficiency, 92.4% efficiency is achieved in the unit board and the efficiency in parallel connection is about 90%.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.15 no.3
• /
• pp.45-53
• /
• 2019

Moving image sharing technology has developed various servers and programs for personal broadcasting. In this paper, we propose the method of transmitting the multiple moving image, including the output channel of external streaming server. It also implements and tests multiple real-time broadcast channel automatic transmission systems that assign multiple output channels to automatic output channels. As a result of the experiment, it is easy to allocate moving image to broadcast channels that are output through the external streaming server's output channels regardless of the size of the streaming server, enabling the management of efficient output channels at the time of transmission of multiple moving image. The moving image can be provided through streaming method regardless of the type of moving image from the moving image provider terminal, and the moving image transmission can be controlled in various ways, including adding and changing channels for which the moving image is sent, and sending delayed to the moving image.

• Journal of Advanced Engineering and Technology
• /
• v.5 no.4
• /
• pp.349-353
• /
• 2012

Recently, Mobile multimedia equipments as smart phone and tablet pc requirement is increasing and this market is also being expanded. These mobile equipments require large multi-media function, so more power consumption is required. For these reasons, the needs of power management IC as switching type dc-dc converter and linear regulator have increased. DC-DC buck converter become more important in power management IC because the operating voltage of VLSI system is very low comparing to lithium-ion battery voltage. There are many people to be concerned about digital DC-DC converter without using external passive device recently. Digital controlled DC-DC converter is essential in mobile application to various external circumstance. This paper proposes the DC-DC Buck Converter using the AVR RISC 8-bit micro-processor control. The designed converter receives the input DC 18-30 [V] and the output voltage of DC-DC Converter changes by the feedback circuit using the A/D conversion function. Duty ratio is adjusted to maintain a constant output voltage 12 [V]. Proposed converter using the micro-processor control was compared to a typical boost converter. As a result, the current loss in the proposed converter was reduced about 10.7%. Input voltage and output voltage can be displayed on the LCD display to see the status of the operation.