• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.4
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• pp.422-427
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• 2014

In this paper, simple LED driver is proposed. The proposed driver has simple construction having series capacitor, bridge rectifier, and adjustable regulator IC. Constant current control is possible with the use of TL431Z. The proposed in this paper, current is greater than the rating of the load, the current controller device measures the increased current in the circuit, and turned-on so that the current will be shared. Thus current control device makes the circuit more reliable, longevity as well as increase the luminous efficacy of the LED light. The simulation and experimental results are presented to show the validity of the proposed circuits.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.357-361
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• 1998

A new current controlled PWM technique for a 3-level inverter has been proposed and described in the paper. The proposed current control has the simple structure without needing to calculate the switching angles of the voltage vectors. The output in the proposed inverter contains less harmonic content than that of a conventional current controlled PWM controller, since the current control can be applied to the 3-level inverter. In addition, the proposed current controlled PWM technique has lower switching frequency than that of a conventional current controlled PWM technique at the same current limit. The control method and the performance for a proposed 3-level inverter has been discussed and investigated by the computer simulation.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.6
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• pp.589-595
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• 2007

This paper presents a new method on controller design of brushless dc motors. In such drives the current ripples are generated by motor inductance in stator windings and the back EMF. To suppress the current ripples the current controller is generally used. To minimize the size and the cost of the drives it is desirable to control motors without the current controller and the current sensing circuits. To estimate the motor CUlTent it is modeled by a neural network that is contigured as an output-error dynamic system. The identified model is essentially a one step ahead prediction structure in which past inputs and outputs are used to calculate the current output. Using the model, a state feedback controller to compensate the effects of disturbance has been designed. The controller is implemented by a 16-bit microprocessor and the effectiveness of the proposed control method is verified through experiments.

• Journal of Power Electronics
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• v.18 no.5
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• pp.1357-1368
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• 2018

In this paper, a novel high gain bidirectional modular dc-dc converter (BMC) with unipolar and bipolar structures for dc network interconnections is proposed. When compared with traditional dc grid-connecting converters, the proposed converter can achieve a high voltage gain with a simple modular transformerless structure. A sub-modular structure for the BMC is proposed to eliminate the unbalanced current stress between the different power units (levels) in the BMC. This can realize current sharing and standardized production and assembling. In addition, phase-interval operation is introduced to the sub-modules to realize low voltage and current ripple in both sides of the converter. Furthermore, two types of bipolar topologies of the sub-modular BMC were proposed to extend its application in bipolar dc network connections. In addition, the control system was optimized for grid-connection applications by providing various control strategies. Finally, simulations of a 3-level unipolar sub-modular BMC and a 4-level bipolar sub-modular BMC were conducted, and a 1-kW experimental 3-level unipolar prototype was developed to verify the effectiveness of the proposed converter.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.1
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• pp.132-139
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• 2005

This paper describes the application of sliding mode control based on the variable structure control(VSC) concept for high-performance position control of an induction servo motor A design method based on external load parameters has been developed for the robust control of AC induction servo drive. Also, a slip frequency vector control with software current control technique has been adopted to achieve fast response of an induction motor drive The position control scheme is comprised of a variable structure controller and slip frequency vector control for inverter fed induction servo motor. Simulated results are given to verify the proposed design method by adoption of sliding mode and show robust control for a change of shaft inertia, viscous friction and torque disturbance.

• Interaction and multiscale mechanics
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• v.3 no.3
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• pp.257-266
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• 2010

A novel resonance based proximity DC current sensor is proposed. The sensor consists of a piezo sensed and actuated cantilever beam with a permanent magnet mounted at its free end. When the sensor is placed in proximity to a wire carrying DC current, resonant frequency of the beam changes with change in current. This change in resonant frequency is used to determine the current through the wire. The structure is simulated in micro and meso scale using COMSOL Multi physics software and the sensor is found to be linear with good sensitivity.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.121-124
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• 2006

In the newly developed control method, the current flowing into SPE cell is the only one considerable factor. So, the structure of control circuit becomes simple and the manufacturing cost of the control device decreases. In conventional power comparison MPPT control method however, a voltage and current coming out from PV cell should be feedbacked to chase maximum power point at every moment. Then, the structure of control circuit becomes so complex and the risk of control failure is much higher than the novel MPPT control method. Therefore, PV generation system by a novel MPPT control method is especially operated much more safely in case of a huge system, because the voltage coming out from PV-cell is not needed to be feedbacked. In this paper, the PV-SPR system was actually manufactured based on the simulation model of PSCAD/EMTDC program and the results tested were shown. Authors are sure that it is the most useful method to maximize power from PV to SPE with only a feedback of SPE input current.

• Earthquakes and Structures
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• v.11 no.6
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• pp.1077-1099
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• 2016

One of the main shortcomings in the current passive base isolation system is lack of adaptability. The recent research and development of a novel adaptive seismic isolator based on magnetorheological elastomer (MRE) material has created an opportunity to add adaptability to base isolation systems for civil structures. The new MRE based base isolator is able to significantly alter its shear modulus or lateral stiffness with the applied magnetic field or electric current, which makes it a competitive candidate to develop an adaptive base isolation system. This paper aims at exploring suitable control algorithms for such adaptive base isolation system by developing a close-loop semi-active control system for a building structure equipped with MRE base isolators. The MRE base isolator is simulated by a numerical model derived from experimental characterization based on the Bouc-Wen Model, which is able to describe the force-displacement response of the device accurately. The parameters of Bouc-Wen Model such as the stiffness and the damping coefficients are described as functions of the applied current. The state-space model is built by analyzing the dynamic property of the structure embedded with MRE base isolators. A Lyapunov-based controller is designed to adaptively vary the current applied to MRE base isolator to suppress the quake-induced vibrations. The proposed control method is applied to a widely used benchmark base-isolated structure by numerical simulation. The performance of the adaptive base isolation system was evaluated through comparison with optimal passive base isolation system and a passive base isolation system with optimized base shear. It is concluded that the adaptive base isolation system with proposed Lyapunov-based semi-active control surpasses the performance of other two passive systems in protecting the civil structures under seismic events.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.227-230
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• 1993

Recently, the development of novel control methodology enables us to improve the performance of AC-machine drives by using pulse width modulation (PWM) technique. Usually, the dynamic characteristic of induction motor (IM) has been represented by the 5-th order nonlinear differential equation. This dynamics, however, can be reduced to 3-rd order dynamics by applying direct control of IM input current. This methodology concludes that it is much easier to control IM by means of the field-oriented methods employing the current controller. Therefore a precise current control is crucial to achieve a high control performance both in dynamic and steady state operations. This paper presents an adaptive fuzzy current controller with artificial neural network (ANN) for field-oriented controlled IM. This new control structure is able to adaptively minimize a current ripple while maintaining constant switching frequency. Especially the proposed controller employs neuro-computing philosophy as well as adaptive learning pattern recognizing principles with respect to variations of the system parameters. The proposed approach is applied to the IM drive system, and its performance is tested through various simulations. Simulation results show that the proposed system, compared among several known classical methods, has a superb performance.

• Journal of IKEEE
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• v.27 no.3
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• pp.308-312
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• 2023

The gate current sensing structure was proposed to more effectively control the regulation of the output voltage when the LDO regulator occurs in an overshoot or undershoot situation. In a typical existing LDO regulator, the regulation voltage changes when the load current changes. However, the operation speed of the pass transistor can be further improved by supplying/discharging the gate terminal current in the pass transistor using a gate current sensing structure. The input voltage of the LDO regulator using the gate current sensing structure is 3.3 V to 4.5 V, the output voltage is 3 V, and the load current has a maximum value of 250 mA. As a result of the simulation, a voltage change value of about 12 mV was confirmed when the load current changed up to 250 mA.