• Journal of Power Electronics
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• v.17 no.4
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• pp.892-904
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• 2017

A design of a Class-E inverter with only one inductor and one capacitor is presented. It is operated at the optimal operation mode for domestic cooker. The design principle is based on the zero-voltage derivative switching (ZVDS) of the Class-E inverter with a parallel load network, which is a parallel resonant equivalent circuit. An induction load characterization is obtained from a large-signal excitation test bench, which is the key to an accurate design of the induction cooker system. Consequently, the proposed scheme provides a more systematic, simple, accurate, and feasible solution than the conventional quasi-resonant inverter analysis based on series load network methodology. The derivative of the switch voltage is zero at the turn-on transition, and its absolute value is relatively small at the turn-off transition. Switching losses and noise are reduced. The parameters of the ZVDS Class-E inverter for the domestic induction cooker must be selected properly, and details of the design of the components of this Class-E inverter need to be addressed. A 1,200 W prototype is designed and evaluated to verify the validation of the proposed topology.

• The KIPS Transactions:PartA
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• v.12A no.6 s.96
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• pp.523-530
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• 2005

When a PCI 2.2 bus master requests data using Memory Read command, a target device may hold PCI bus without data to be transferred for long time because a target device needs time to prepare data infernally. Because the usage efficiency of the PCI bus and the data transfer efficiency are decreased due to this situation, the PCI specification recommends to use the Delayed Transaction mechanism to improve the system performance. But the mechanism cann't fully improve performance because a target device doesn't know the exact size of prefetched data. In the previous work, we propose a new method called Prefetch Request when a bus master intends to read data from the target device. In this paper, we design PCI 2.2 controller and local device that support the proposed method. The designed PCI 2.2 controller has simple local interface and it is used to convert the PCI protocol into the local protocol. So the typical users, who don't know the PCI protocol, can easily design the PCI target device using the proposed PCI controller. We propose the basic behavioral verification, hardware design verification, and random test verification to verify the designed hardware. We also build the test bench and define assembler instructions. And we propose random testing environment, which consist of reference model, random generator ,and compare engine, to efficiently verify corner case. This verification environment is excellent to find error which is not detected by general test vector. Also, the simulation under the proposed test environment shows that the proposed method has the higher data transfer efficiency than the Delayed Transaction about $9\%$.

• Journal of Power Electronics
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• v.16 no.4
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• pp.1375-1386
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• 2016

To decouple the secondary saliencies in sensorless permanent magnet synchronous machine (PMSM) drives, a repetitive control (RC) in the angle domain is proposed. In this paper, the inductance model of a concentrated windings surface-mounted PMSM (cwSPMSM) with strong secondary saliencies is developed. Due to the secondary saliencies, the estimated position contains harmonic disturbances that are periodic relative to the angular position. Through a transformation from the time domain to the angle domain, these varying frequency disturbances can be treated as constant periodic disturbances. The proposed angle-domain RC is plugged into an existing phase-locked loop (PLL) and utilizes the error of the PLL to generate signals to suppress these periodic disturbances. A stability analysis and parameter design guidelines of the RC are addressed in detail. Finally, the proposed method is carried out on a cwSPMSM drive test-bench. The effectiveness and accuracy are verified by experimental results.

• Journal of Multimedia Information System
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• v.6 no.4
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• pp.239-244
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• 2019

With the development of Cyber-Physical Systems(CPS), several technologies such as automation control, automotive and intelligent house systems have been developed. To enable communication among various components of such systems, several wired and wireless communication protocols are used. The Controller Area Network(CAN) is one of such wired communication protocols that is popularly used for communication in automobiles and other machinery in the industry. In this paper, we designed and implemented a response time analysis system for CAN communication. The reliable data transfer among various electronic components in a significant time is crucial for the smooth operation of an electric vehicle. Therefore, this system is designed to conveniently analyze the response time of various electronic components of a CAN enabled system. The priority for transmission of the messages in the CAN bus is determined by the message identifier. As the number of nodes increases the transmission of low priority messages is delayed due to the existence of higher priority messages on the bus. We used Raspberry Pi3 and PiCAN2 board to simulate the data transfer for studying the comparative delay in low priority nodes.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.920-925
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• 2001

A study on the topology optimization of a multi-spectral camera for space-use is presented. A multi-spectral camera for space-use experiences degradation of optical image in the space, which can not be detected on the optical test bench on the earth. An optical surface deformation of a primary mirror, which is a principal component of the camera system, under the self-weight loading is an important factor affecting the optical performance of the whole camera system. In this study, topology optimization of the primary mirror of the camera is presented. Total mass of the primary mirror is given as a constraint to the optimization problem. The sensitivities of the objective function and constraint are calculated by direct differentiation method. Optimization procedure is carried out by an optimality criterion method using the sensitivities of the objective function and the constraint. As a preliminary example, topology optimization considering a self-weight loading is treated. For practical use, the polishing pressure is included as a loading in the topology optimization of the primary mirror. Results of the optimized design topology for the primary mirror with varying mass ratios are presented.

• Textile Coloration and Finishing
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• v.25 no.2
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• pp.134-139
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• 2013

A tenter is very important to dry and heat-set fabrics in textile dyeing and finishing industry. However, the tenter machine typically utilizes more than 80% of all the power in dyeing system, and yet is one of the primary machine which affects quality of fabrics. Therefore, performance optimization of the tenter machine is required to reduce energy consumption and enhance quality of fabrics. To optimize the tenter machine, it is important to maintain the uniform flow rate, which can be obtained by optimizing a nozzle geometry. In this study, emboss hole angle was investigated as main parameter in flow rate uniformity and heat flux efficiency. The analysis results were compared with those acquired from bench-scale dryer test in the laboratory. The tenter machine performance simulated by Computational Fluid Dynamics(CFD) was optimized by controlling emboss hole angle.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.2
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• pp.93-100
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• 2005

Stringent emission regulations and increasing demands on reductions of noise and vibration of common rail direct injection (CRDI) diesel engines lead to the advent of piezo-actuated injectors. Compared with solenoid-actuated injectors, piezo-actuated injectors generate greater force and give faster response time, resulting in more accurate and faster injections. The accurate and fast response of an injector can offer an opportunity to control the combustion process and pollutant formation. In this study, the mathematical model of a piezo-actuated injector is developed. An estimator of the injection rate of the piezo-actuated injector is designed based on this model. The sliding mode theory is applied to the estimator design in order to overcome model uncertainties. The injector model and the estimator are verified by the injection experiments in an injector test bench. The simulation and the experimental results show that the proposed sliding mode observer can effectively estimate the injection timing and the injection rate of the piezo-actuated injector.

• Korean Chemical Engineering Research
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• v.59 no.3
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• pp.467-479
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• 2021

Abstract: A kinetic model was developed for the dehydration of ethanol to ethylene based on two parallel reaction pathways. Kinetic parameters were estimated by fitting experimental data of powder catalysts in a lab-scale test, and the effectiveness factor was determined using data from pellet-type catalysts in bench-scale experiments. The developed model was used to design a multitubular fixed-bed reactor (MTR) and an adiabatic reactor (AR) at a 10 ton per day scale. The two different reactor types resulted in different process configurations: the MTR consumed the ethanol completely and did not produce the reaction intermediate, diethyl ether (DEE), resulting in simple separation trains at the expense of high equipment cost for the reactor, whereas the AR required azeotropic distillation and cryogenic distillation to recycle the unreacted ethanol and to separate the undesired DEE, respectively. Quantitative analysis based on the equipment and annual energy costs showed that, despite high equipment cost of the reactor, the MTR process had the advantages of high productivity and simple separation trains, whereas the use of additional separation trains in the AR process increased both the total equipment cost and the annual energy cost per unit production rate.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.3
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• pp.176-182
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• 2021

This research proposes a high-frequency circuit that can accurately predict the differential mode noise of single-phase inverters at the circuit design stage. Proposed single-phase inverter high frequency circuit in the work is a form in which harmonic impedance components are added to the basic single-phase inverter circuit configuration. For accurate noise prediction, parasitic components present in each part of the differential noise path were extracted. Impedance was extracted using a network analyzer and Q3D in the measurement range of 150 kHz to 30 MHz. A high-frequency circuit model was completed by applying the measured values. Simulations and experiments were conducted to confirm the validity of the high-frequency circuit. As a result, we were able to predict the resonance point of the differential mode voltage extracted as an experimental value with a high-frequency circuit model within an approximately 10% error. Through this outcome, we could verify that differential mode noise can be accurately predicted using the proposed model of the high-frequency circuit without a separate test bench for noise measurement.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.827-838
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• 2023

Centrifugal pump is a key part of nuclear power plant systems, and its health status is critical to the safety and reliability of nuclear power plants. Therefore, fault diagnosis is required for centrifugal pump. Traditional fault diagnosis methods have difficulty extracting fault features from nonlinear and non-stationary signals, resulting in low diagnostic accuracy. In this paper, a new fault diagnosis method is proposed based on the improved particle swarm optimization (IPSO) algorithm-based variational modal decomposition (VMD) and relevance vector machine (RVM). Firstly, a simulation test bench for rotor faults is built, in which vibration displacement signals of the rotor are also collected by eddy current sensors. Then, the improved particle swarm algorithm is used to optimize the VMD to achieve adaptive decomposition of vibration displacement signals. Meanwhile, a screening criterion based on the minimum Kullback-Leibler (K-L) divergence value is established to extract the primary intrinsic modal function (IMF) component. Eventually, the factors are obtained from the primary IMF component to form a fault feature vector, and fault patterns are recognized using the RVM model. The results show that the extraction of the fault information and fault diagnosis classification have been improved, and the average accuracy could reach 97.87%.