Kang-Yeon Lee

Performance analysis of the DTC using a closed loop stator flux observer for induction motor in the low speed range

Direct torque control (DTC) of an AC motor has the fast torque and flux dynamic responses even though it has very simple scheme to implement. However, DTC do not show good performance at low speed range with conventional open loop stator flux observer when stator resistance varied. Therefore, authors propose a new nonlinear stator flux observer in order to estimate the stator flux of induction motor at low speed and show its simulation results.

A Study of the PV System for Optimum Design Methods With Loss Parameter Compensation

Photovoltaic systems utilize the infinite clean energy of the sun, without creating any air pollution or noise and mechanical vibration. A PV system operates without the need of fuel, rotation surfaces, high temperatures or high pressures. It is therefore to do maintain and simple to install as well as having a long life cycle. The global market for PV systems continues to grow rapidly by 30[%] per year. This paper suggests a new design method for the PV system installation that will allow to the improvement of system efficiency. This method is in accordance with the loss parameter compensation method designed for the PV systems and investigated through simulation and practical experimentation. It was applied to an interconnected 10[㎾] grid PV system and was demonstrated in the field. Features such as solar array, KS, system efficiency, performance and stability were considered. Through the proposed optimal parameter design method, the features of the system were studied, and the 10[㎾] PV system was demonstrated and analyzed.

Electrical properties of organic light-emitting diodes by indium tin oxide chemical-mechanical polishing process

In this study, the optimum process parameters and the influences of their process parameters were investigated for indium tin oxide chemical-mechanical polishing (ITO-CMP) with a sufficient removal amount and good planarity. Next, the organic light-emitting display (OLED) device with the structure of glass∕ITO∕poly[2-methoxy-5-(2-ethylhexyloxy)-p-phenylenevinylene]∕Al using a polished ITO surface as a bottom electrode (anode) was fabricated. The electrical characteristics, such as sheet resistance and current-voltage (I‐V) relationship, are discussed in order to evaluate the possibility of the CMP application for an OLED device using an ITO film. The surface morphology and I‐V characteristics of ITO thin film were improved after the CMP process using optimized process parameters compared to that of the as-deposited thin film before the CMP process.

Direct torque control for the 4-phase switched reluctance motor drives

This paper presents a novel control method for the sensorless four phase switched reluctance motor drives, i.e. 8 stator and 6 rotor. The sensorless control is based on direct torque control with direct flux compensation (DFC) for switched reluctance motor drives. The use of direct torque control, implemented in AC drives with a varies degree of success, has yet been completely applied for SRM especially 8/6, 4-phase SRM. Direct torque control strategy implemented to control unit, well known advantages such as simple and robust structure, wide torque speed range and no maintenance. In this paper, we propose a novel way to utilize the 8/6 4 phase switched reluctance motor and the paper then explains the algorithm to be employed in new DTC scheme in SRM drives with simulation results are presented.

Yield improvement of 0.13μm Cu/low-k dual-damascene interconnection by organic cleaning process

Cu/low-k dielectrics are required to reduce resistance-capacitance (RC) delay and parasitic capacitance at the back-end-of-line (BEOL) interconnection. Integration of Cu/low-k dielectrics (black diamond) for BEOL interconnection in 0.13μm technology has gained wide acceptance in the microelectronics industry in recent years. In this article, the authors discuss the process-integration issues of 0.13μm Cu/low-k dual-damascene integration for static random access memory (SRAM) device yield. The same scheme of 0.13μm Cu/fluorinated silicate glass–based device was used for the full process of making a low-k based device. Black diamond was used as a low-k material with a dielectric constant of 2.95. To reduce the damage of low-k and improve the yield of a low-k based device, H2O ashing, organic cleaning, and reduced down pressure in chemical-mechanical planarization were selected for the study. Specifically, the cleaning process after the ashing process was very effective for the removal of organic residues fr...

Optimized Digital Proportional Integral Derivative Controller for Heating and Cooling Injection Molding System

Proportional integral derivative (PID) control is one of the conventional control strategies. Industrial PID control has many options, tools, and parameters for dealing with the wide spectrum of difficulties and opportunities in manufacturing plants. It has a simple control structure that is easy to understand and relatively easy to tune. Injection mold is warming up to the idea of cycling the tool surface temperature during the molding cycle rather than keeping it constant. This “heating and cooling” process has rapidly gained popularity abroad. However, it has discovered that raising the mold wall temperature above the resin’s glass-transition or crystalline melting temperature during the filling stage is followed by rapid cooling and improved product performance in applications from automotive to packaging to optics. In previous studies, optimization methods were mainly selected on the basis of the subjective experience. Appropriate techniques are necessary to optimize the cooling channels for the injection mold. In this study, a digital signal processor (DSP)-based PID control system is applied to injection molding machines. The main aim of this study is to optimize the control of the proposed structure, including a digital PID control method with a DSP chip in the injection molding machine.

Heat & Cool Injection Molded Fresnel Lens Solar Concentrators

A Fresnel lens is an optical component which can be used as a cost-effective, lightweight alternative to conventional continuous surface optics. Fresnel lens solar concentrators continue to fulfill a market requirement as a system component in high volume cost effective Concentrating Photovoltaic (CPV) electricity generation. The basic principles of the fresnel lens are reviewed and some practical examples are described. To investigate the performance space of the Fresnel lens, a fast simulation method which is a hybrid between raytracing and analytical computation is employed to generate a cache of simulation data. Injection molders are warming up to the idea of cycling their tool surface temperature during the molding cycle rather than keeping it constant. Heat and cool process are now also finding that raising the mold wall temperature above the resin`s glass-transition or crystalline melting temperature during the filling stage and product performance in applications from automotive to packaging to optics. This paper deals with the suitability of Fresnel lenses of imaging and non-imaging designs for solar energy concentration. The concentration fresnel lens confirmed machinability and optical transmittance and roughness measure through manufactured the prototype.

Performance Evaluation of a Solar Tracking PV System with Photo Sensors

The conversion of solar radiation into electrical energy by Photo-Voltaic (PV) effect is a very promising technology, being clean, silent and reliable, with very small maintenance costs and small ecological impact. The output power produced by the PV panels depends strongly on the incident light radiation. The continuous modification of the sun-earth relative position determines a continuously changing of incident radiation on a fixed PV panel. The point of maximum received energy is reached when the direction of solar radiation is perpendicular on the panel surface. Thus an increase of the output energy of a given PV panel can be obtained by mounting the panel on a solar tracking device that follows the sun trajectory. Tracking systems that have two axes and follow the sun closely at all times during the day are currently the most popular. This paper presents research conducted into the performance of Solar tracking system with photosensors. The results show that an optimized dual-axis tracking system with photosensor performance and analysis. From the obtained results, it is seen that the sun tracking system improves the energy and energy efficiency of the PV panel.ti-junction CPV module promises to accelerate growth in photovoltaic power generation.

Applied Spherical Lens with Reflect Mirror for the CPV module

There are two main types of concentrating optical systems in use today: refractive types that use Fresnel lenses, and reflective systems that use one or more mirrors. Regardless of the chosen optical system, the result is concentrated sunlight being aimed at the sensitive face of the cell, to produce more energy from less photovoltaic material. In this paper, for the achieve trackerless CPV system, CPV module included that the spherical lens with reflect mirror makes it possible to achieve high and stable power generation performance for the high concentration photovoltaic power generation system and cope with the needs for a variety of shapes and sizes in flexible manners and that the multiple cavity assemble method greatly reduces costs. Development of these high performance multi-junction CPV module promises to accelerate growth in photovoltaic power generation.

A Study On The Stator Slot Shape Design of BLDC Motor

In this paper, we studied an optimal design and efficiency improvement of the BLCD motor used in home electronic appliance. The number of stator slots is chosen depending on the rotor poles, phase number, and the winding configuration. In general, a fractional slots/pole design is preferred to minimize cogging torque. To reduce the winding resistance, we reduced the coil length and we improved the coil space factor. We proposed three types of stator slot shape design for the optimal BLDC motor design. One of them, U-type slot shape is a best optimal design, it proved by the simulated and tested. Optimal design of essential parameters aiming at high winding factor are presented to create for a high-quality system implementation. Design analysis is verified by testing and building a prototype motor.