• Journal of Electrical Engineering and Technology
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• v.11 no.3
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• pp.629-638
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• 2016

This paper proposes a State-of-Charge (SOC) balancing control of Battery Power Modules (BPMs) for a modularized battery for Electric Vehicles (EVs) without additional balancing circuits. The BPMs are substituted with the single converter in EVs located between the battery and the inverter. The BPM is composed of a two-phase interleaved boost converter with battery modules. The discharge current of each battery module can be controlled individually by using the BPM to achieve a balanced state as well as increased utilization of the battery capacity. Also, an SOC balancing method is proposed to reduce the equalization time, which satisfies the regulation of a constant DC-link voltage and a demand of the output power. The proposed system and the SOC balancing method are verified through simulation and experiment.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1864-1869
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• 2003

A novel piezoelectric micropump using active check valves in place of conventional passive check valves in inlet and outlet has been proposed and investigated. It actively controls open/close motion of check valves using piezoelectric actuator for expansion/contraction of pump chamber. In this paper, bi-directional flow characteristics and load characteristics are experimentally investigated using an adequate timing control for valve closing motion with a prototype micropump fabricated with the effective size of $17{\times}8{\times}11mm^{3}$. From the experimental results, it is ascertained that optimal values of phase shift against voltage to drive pump chamber for realization of a miniaturized but powerful micropump, are $15^{\circ}$ in inlet check valve and $195^{\circ}$ in outlet. Based on the obtained results, a sheet-type active shuttle valve that has a unified valve-body for inlet and outlet check valves is proposed. A micropump with the effective size of $10{\times}10{\times}10mm^{3}$ is fabricated and basic characteristics are experimentally investigated.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1169-1170
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• 2006

Grid connected PV(Photovoltic) generation systems are becoming and actual and general. The power output of PV system is directly affected by the weather conditions. And when AC power supply is needed, power conversion by an inverter and a MPPT control are necessary. The PV power generation system can be treated to a harmonics source for the power distribution system. So, the PV system combined the function of active filter system can be useful applied in power distribution system. AF(Active Filters) intended for harmonic solutions are expending their functions from harmonic compensation of nonlinear loads into harmonic isolation between utilities and consumer. With the test analysis of the proposed control strategy of PV-AF system, the outcome of the test shows the stability and effectiveness of the proposed PV-AF system. The various capability of AF has been proved in previous research and usage. In this paper, authors present a DSP controlled PV-AF system for power conditioning in three-phase industrial or commercial power systems and verify it through experimental results.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.198-200
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• 2018

In this paper a single-stage single-phase differential type isolated AC-DC converter is proposed. This converter eliminates the requirement to use bulky electrolytic capacitor from the system and at the same time provides DC charging by employing the AC Power Decoupling waveform control method. All the switches of the converter achieve ZVS turn on during half line cycle and all diodes achieve ZCS turn off during entire line cycle. A conventional controller is implemented for PFC control and output regulation, whereas a power decoupling controller is added to compensate $2^{nd}$ harmonic ripple power. In addition, an interleaving technique is applied to increase the power range of the converter and reduce the input inductor size. In the end simulation verification is performed and results are obtained for 6.6KW.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.4
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• pp.395-401
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• 1999

In this paper, a temperature controller for a semiconductor test handler is proposed. First, a handware system for identification and control is established using RTD sensors, an A/D converter, solid state relays, a heater, and a computer system. Second, using ARMAX model and least square method, a chamber model for the design of a controller is identified through experiments. The identified model is verified to describe the real plant very well in the sense that it shows very similar input-output responses to those of the real system. With the identified model an LQG controller is designed. Frequency response of the designed controller shows that it has 15 dB of gainmargin and (-50˚, +50˚) of phase margin. Experiment with a real test handler demonstrates a good performance in the sense that its overshoot and steady state error are smaller and response time is faster, compared with those of a conventional PID controller.

• Journal of Power Electronics
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• v.18 no.1
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• pp.23-33
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• 2018

Silicon Carbide (SiC) MOSFET belongs to the family of wide-band gap devices with inherit property of low switching and conduction losses. The stable operation of SiC MOSFET at higher operating temperatures has invoked the interest of researchers in terms of its application to high power density (HPD) power converters. This paper presents a performance study of SiC MOSFET based two-phase interleaved boost converter (IBC) for regulation of avionics bus voltage in more electric aircraft (MEA). A 450W HPD, IBC has been developed for study, which delivers 28V output voltage when supplied by 24V battery. A gate driver design for SiC MOSFET is presented which ensures the operation of converter at 250kHz switching frequency, reduces the miller current and gate signal ringing. The peak current mode control (PCMC) has been employed for load voltage regulation. The efficiency of SiC MOSFET based IBC converter is compared against Si counterpart. Experimentally obtained efficiency results are presented to show that SiC MOSFET is the device of choice under a heavy load and high switching frequency operation.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.11
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• pp.1074-1081
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• 2011

As robotics systems are becoming more complex there is the need to promote component based robot development, where systems can be constructed as the composition and integration of reusable building block. One of the most important challenges facing component based robot development is safeguarding against software component failures and malfunctions. The health monitoring of the robot software is most fundamental factors not only to manage system at runtime but also to analysis information of software component in design phase of the robot application. And also as a lot of monitoring events are occurred during the execution of the robot software components, a simple data treatment and efficient memory management method is required. In this paper, we propose an efficient events monitoring and data management method by modeling robot software component and monitoring factors based on robot software framework. The monitoring factors, such as component execution runtime exception, Input/Output data, execution time, checkpoint-rollback are deduced and the detail monitoring events are defined. Furthermore, we define event record and monitor record pool suitable for robot software components and propose a efficient data management method. To verify the effectiveness and usefulness of the proposed approach, a monitoring module and user interface has been implemented using OPRoS robot software framework. The proposed monitoring module can be used as monitoring tool to analysis the software components in robot design phase and plugged into self-healing system to monitor the system health status at runtime in robot systems.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.3
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• pp.171-183
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• 2018

Herein, we show the design and fabrication of a serial-to-parallel converter (SPC) using the $0.25-{\mu}m$ GaAs pHEMT process. The serial-to-parallel converter is composed of four bits to control the four phase shifters used in the core chip. The SPC stores the received serial data signal to a register in the SPC and converts the stored data into the parallel data. Each converted output data can control four phase shifters. The size of the fabricated SPC is $1,200{\times}480{\mu}m^2$ and it uses two DC power supplies of 5 V and -3 V. The consumption current of each DC power supply is 7.1 mA for 5 V, and 2.1 mA for -3 V.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.2
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• pp.212-215
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• 2016

In this paper, a 5.08 GHz Ring Voltage Controlled Oscillator(Ring VCO) was implemented using $0.18{\mu}m$ standard CMOS technology. The proposal Ring VCO is 3-stage structure. This research confirmed that the each stage's different transistor size ratio influence the current change and alter power consumption consequentially. This circuit is formed to control the current thereby adding the Current Mirror and to tune the frequency by supplying control voltage. It has an 65.5 %(1.88~5.45 GHz) tuning range. The measured output power is -0.30 dBm. The phase noise is -87.50 dBc/Hz @1 MHz offset with operating frequency of 5.08 GHz fundamental frequency. The total power consumption of Ring VCO is 31.2 mW with 2.4 V supply voltage.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.6
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• pp.617-626
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• 2010

In this paper, we have proposed and experimentally performed a polarization and phase control method of an optical signal which has same wavelength with the optical carrier to improve phase characteristics of a continuous wave(CW) generated by the double sideband-suppressed carrier(DSB-SC) as one of the famous photomixing technique for making sub-millimeter and terahertz waves. A polarization and phase controlled optical signal has been coupled with the general DSB-SC on an optical coupler. The output of the optical coupler is then photomixed by a photomixer. From our analysis and measurement results, we have found that the amplitude of the generated sub-mm and terahertz CW signal is higher 1.5 dB and the phase noise is lower about 3 dB@10 kHz offset frequency than the general DSBSC. Consequently, since our proposed method has improved the amplitude and phase noise of CW signals in the sub-mm and terahertz bands, it can be helpful results to make low cost CW generator in sub-millimeter and subterahertz bands.