• Proceedings of the KIEE Conference
• /
• 2007.04c
• /
• pp.56-58
• /
• 2007

This paper deals with analytical prediction for the cogging torque of permanent magnet machines with multi-pole rotor First. open-circuit field solutions are derived using a magnetic vector potential and a two-dimensional (2-d) polar coordinate systems. On the basis of derived open-circuit field solutions and 2-d permeance functions. we also derive the analytical solutions for the open-circuit field considering stator slotting effects and cogging torque. All analytical results are shown in goof agreement with those obtained from finite element (FE) analyses.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.18 no.2
• /
• pp.199-204
• /
• 2013

Recently, the demand for fuel efficient electric vehicles (EVs) and hybrid electric vehicles (HEVs) has been growing globally. Due to the increased number of switching devices in the electrified vehicles, the probability of the semiconductor device failure is much higher than in other application areas. A sudden failure in one of the power switches and insufficient power management ability in the systems not only decreases system performance, but also leads to critical safety problems. In this paper, novel switch open circuit fault detection method is proposed, and the proposed approach is verified by experiments.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.21 no.6
• /
• pp.78-84
• /
• 1984

We propose a new algorithm which detects stuck-open faults in CMOS circuits without being affected by time skews not using additional circuits. That is, the Domino CMOS circuit structure is used as circuit configurations and the clocking gate in this circuit is modeled as one branch, then test sequence is generated by using the transition test. Also, it is verified by applying this algorithm implemented in VAX II/780 to arbitrary CMOS circuits that all of stuck-open faults which were not detected because of time skews in conventional methods is detected.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2004.10a
• /
• pp.134-138
• /
• 2004

The discrepancies between theoretical values and measured data of PEFC(Proton Exchange Fuel Cell) is carried out for the machine tool power generation. Rudimental approach of theoretical fuel cell open circuit potential using Gibbs free energy is employed for the examination of PEFC module. The stack temperature, stack voltage and stack current are measured during the operation of PEFC module. It is found that stack voltage and current values show the pronounced discrepancy with the results calculated by Gibbs free energy approach. It is analysed that the discrepancy is due to activation polarization, concentration overvoltage and ohmic overvoltage.

• Transactions of the Korean hydrogen and new energy society
• /
• v.3 no.2
• /
• pp.63-69
• /
• 1992

Two unit cells were made and operated with oxygen and air as oxidants After 350 hours operation with oxygen, the open circuit voltage drop of unit cell was 30 mV and internal resistance increased. After 250 hours operation with air, the open circuit voltage drop was 130mV. And the open circuit voltage difference of two cases was 90mV. In order to improve the performance of the unit cell with air, the supplying method of the electrolyte and the mass transfer characteristics of the electrode should be studied.

• Journal of Electrochemical Science and Technology
• /
• v.13 no.3
• /
• pp.369-376
• /
• 2022

In this study, the stability of an anion exchange membrane water electrolyzer (AEMWE) cell was evaluated in an on-off cycling operation with respect to an applied electric bias, i.e., a current density of 500 mA cm^-2, and an open circuit. The ohmic and polarization resistances of the system were monitored during operation (~800 h) using electrochemical impedance spectra. Specific consideration was given to the ohmic resistance of the cell, especially that of the membrane under on-off cycling conditions, by consistently feeding the cell with KOH solution. Owing to an excess feed solution, a momentary increase in the polarization resistance was observed immediately after the open-circuit. The excess feed solution was mostly recovered by subjecting the cell to the applied electric bias. Stability tests on the AEMWE cell under on-off cycling with continuous feeding even under an open circuit can guarantee long-term stability by avoiding an irreversible increase in ohmic and polarization resistances.

• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.1760-1764
• /
• 2003

This study was carried out to establish an analytical method on the open circuit seawater pipeline network for open rack vaporizers(ORVs). The linear theory method was chosen to solve this network system. In particular, the method was modified to calculate the static pressure at each node and to determine the operating condition of each pump with the mean static pressure of pumps and ORVs. The proposed method is the first report demonstrating that can be used as a solver for the complicated open circuit. Also, the method indicated the importance for exactly calculating equivalent length of pipes including valves, bends, fittings, and others to raise the accuracy. Although this technique is good for solving this system, it is still required to improve the convergence rate.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.11
• /
• pp.2487-2494
• /
• 2012

In this paper, a thermal energy harvesting circuit with MPPT control is designed. MPPT(Maximum Power Point Tracking) control function is implemented using the linear relationship between the open-circuit voltage of a thermoelectric generator(TEG) and its MPP voltage. The designed MPPT control circuit traces the maximum power point by periodically sampling the open circuit voltage of a TEG, makes the reference voltages using sampled voltage and delivers the maximum available power to load. Simulation results show that the maximum power efficiency of the designed circuit is 94%. The proposed thermal energy harvesting circuit is designed with $0.35{\mu}m$ CMOS process, and the chip area except PAD is $1168.7{\mu}m{\times}541.3{\mu}m$.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.22 no.8
• /
• pp.45-51
• /
• 2008

HID(High Intensity Discharge) search lamp for shipment requires a high open circuit and output current compare than vehicle. This paper presents a soft-start open circuit voltage and constant current sequence control method for 2.5[kW] HID search lamp. The proposed method controls the opal circuit voltage and discharge current of HID lamp according to ignition signal with a simple 8-bit micro-processor and PWM device. For the stable control of lamp, micro-processor checks the output voltage and current. And the checked signals are compared with ignition signal and changes the control mode for stable operation. An ignition signal and micro-processor change the control mode from open circuit voltage contort to constant current control. The proposed control scheme is verified from experimental tests of 2.5[kW] HID search lamp for shipment.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.45 no.2
• /
• pp.34-43
• /
• 2008

An OpenLDI receiver circuit for flat-panel display systems was designed and fabricated using $1.8-{\mu}m$ high-voltage CMOS technology. Designed circuit roughly consists of DLL circuit and parallelizers, which recovers clock and parallelize data bits, respectably. It has one clock input and four data inputs. Measurement results showed that it successfully recovers clock signal from input whose frequency is $10Mhz{\sim}65Mhz$, which corresponds data rate of $70Mbps{\sim}455Mbps$ per channel, or $280Mbps{\sim}1.82Gbps$ when all of the four data channels were utilized. A commercial LCD monitor was modified into a test-bench and used for video data transmission at clock frequency of 49Mhz. In the experiment, power consumption was 19mW for core block and 82.5mW for output buffer.