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Simplified Analysis and Validation of a Two-switch Flyback Converter
(2024-01-01)
Wuti, Virot
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Bunlaksananusorn, Chanin
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Trakuldit, Siripan
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Tattiwong, Kaweewat
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Luangpol, Amata
This paper presents a simplified analysis and validation of a two-switch flyback converter. When parasitic components, i.e. the MOSFET's output capacitance and transformer's leakage inductance, are neglected, circuit analysis of the two-switch flyback converter is greatly simplified and derivation of the converter equations becomes straightforward. The validity of the derived equations, which are useful for the converter design, is confirmed by simulation and experimental results.
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Cycle Time Reduction for Productivity Improvement in an Engine Assembly Industry
(2023-01-01)
Wongsomboon, Chanathip
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Maneerat, Noppadol
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Thudthong, Jakkrit
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Sukasem, Sutikamon
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Luangpol, Amata
The production process improvement is a solution to increase the efficiency of productivity. The improvement is applied to the production process gradually and continuously for the production process balancing. This research uses the cycle time and waste disposal, which are important tools that can be used to analyse the lost process time and waste in all aspects of business. There are guidelines for classifying the types of waste into seven groups. In addition, there are electric torque wrench to one workstation and production line balancing to reduce the cycle time. Finally, the production cycle time is reduced by 14 percents then the production cost is also reduced, and the company can get more profit.
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A Simplified Analysis and Design of an RCD Clamp Forward Converter
(2022-01-01)
Wuti, Virot
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Trakuldit, Siripan
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Luangpol, Amata
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Tattiwong, Kaweewat
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Taylim, Alisala
A conventional forward converter requires a transformer having an extra winding to assist in magnetic core reset, thus complicating the design and increasing the production cost. These shortcomings can be overcome by using an RCD clamp forward converter. This article presents a simplified analysis and design of the RCD clamp forward converter. The laboratory prototype is constructed. Experimental results demonstrates that the prototype converter is capable of providing a constant output voltage throughout its operating condition and has the maximum efficiency of 85%.
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Frequency Domain Spectroscopy Analysis of the Water Tree XLPE Cable
(2022-01-01)
Sawatdimongkol, Whichakorn
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Chancharoensook, Phop
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Sawatdimongkol, Worachai
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Taylim, Alisala
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Luangpol, Amata
Water tree is one type of insulation deterioration occurring in polymeric cables such as polyethylene, ethylene-propylene rubber, and cross-linked polyethylene (XLPE) caused by the existing impurities in the bulk insulation or imperfection of the semiconductive surface. Moreover, the water tree phenomenon affects the cable's overall lifetime and can be developed into an electrical tree, leading to the failure of the cable. Because of this, the evaluation of water trees becomes one of the most important factors in the condition assessment of the cable. This paper presents the comparison of the dielectric properties of 22 kV XLPE underground cable between aged and new (unused) cables. Furthermore, the water tree was detected in the aged cable. Besides, the evaluation of aged and new cables was performed by frequency-domain spectroscopy (FDS), which measures the insulation's complex capacitance and dissipation factors in the frequency domain. Then, the aged and new cables' complex capacitance and dissipation factor were compared. The test result found that the dissipation factor and imaginary part of the complex capacitance of the aged cable have a higher value than these of the new cable. More or less, the results show that FDS is one of the non-destructive testing methods suitable for assessing the condition of the cable insulation, which deteriorated by water tree.
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Position signal detector for linear variable differential transformer
(2020-12-01)
Rerkratn, Apinai
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Luangpol, Amata
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Petchmaneelumka, Wandee
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Riewruja, Vanchai
This paper presents the position signal detector for linear variable differential transformer (LVDT) based on RMS-to-DC converter. The proposed detector consists of the differential amplifier, the comparator, the phase detector, the controllable unity-gain inverting/non-inverting amplifier and the RMS-to-DC converter. The proposed technique provides a simple scheme and uses the low cost commercial available devices such as opamp, transistor and digital logic gate. The experimental testing with the commercial LVDT model OP12.5G from Solartron Metrology showing the proposed position signal detector can produce the output voltage corresponding to the measured displacement with satisfactory values and good linearity.
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Simple LVDT demodulator
(2020-10-13)
Rerkratn, Apinai
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Luangpol, Amata
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Riewruja, Vanchai
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Petchmaneelumka, Wandee
A simple technique to realize demodulator for linear variable differential transformer (LVDT) is presented in this paper. The proposed LVDT demodulator is based on sample and hold technique. The proposed scheme consists of peak detector, phase detector, monostable circuit, sample and hold circuit, and controllable unity-gain inverting/noninverting amplifier. The presented technique employs the simple and low-cost devices such as op-amp, and digital logic gate. Experimentation with the commercial LVDT model OP12.5G from Solartron metrology shows that the proposed LVDT demodulator provides the output voltage corresponding to the movement of LVDT core with satisfactory values and good linearity. The maximum error of the proposed demodulator is about 1.5%. In addition, the output magnitude of proposed LVDT demodulator can be adjusted by variable resistor (VR1) without the external circuit requirement.
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Analysis and design of a zero-voltage-switched (ZVS) quasi-resonant buck converter operating in full-wave mode
(2020-07-01)
Wuti, Virot
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Luangpol, Amata
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Tattiwong, Kaweewat
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Trakuldit, Siripan
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Taylim, Alisala
Hard-switching is typically used in most DC-DC converters, where transition of a power switch occurs when it still carries current and is subject to voltage at the same time. The hard-switching operation incurs high stress and switching losses to the device. These problems can be alleviated by zero voltage switching in which a power switch is made to turn on and off at zero voltage. This paper presents analysis and design of a Zero-Voltage-Switched (ZVS) quasi-resonant buck converter operating in full-wave mode. The prototype converter is designed and built. Test results show that the designed converter achieves zero voltage switching and possesses good output regulation throughout its operating range.
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Real-time seafood quality monitoring system using interdigital sensor
(2020-01-01)
Kaewpoonsuk, Anucha
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Luangpol, Amata
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Prasitmeeboon, Pitcha
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Rerkratn, Apinai
Many studies showed that seafood consumption contains many health benefits. However, the spoilage of such products causes the vast economic loss each year. An effective monitoring and inspection system for quality is required during the storage of these products. Most existing methods for such inspection require laboratory tests. In this study, the interdigital sensor was developed and applied to inspect the spoilage of seafood. The sensor was designed to monitor the change of impedance during spoilage progression of seafood. The result revealed that impedance of liquid decreased overtime. This coincides with the fact that spoilage of seafood generates ammonium ion which causes decrease in the impedance of the liquid. The designed sensor was then merged with the proposed system which consists of a sine wave circuit, a voltage control current source circuit, an interdigital sensor, an amplifier circuit, a rectifier circuit, a low-pass filter circuit, a comparator circuit and a display circuit. These circuits adjusted the signals received from the sensor to be proper to the application. The experiment was designed to have conditions similar to the real-world situation of how seafood is stored. The experimental results showed that the proposed system effectively indicated the change of seafood quality.
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Performance comparison between a two-switch and RCD clamp forward converters
(2019-07-01)
Wuti, Virot
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Luangpol, Amata
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Tattiwong, Kaweewat
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Sopin, Anan
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Sirisuk, Phaophak
This paper presents performance comparison between a two-switch and RCD clamp forward converters. The performance comparison is carried out through experimentation on the two prototype circuits, which have the same circuit specifications and similar component values. Aspects to be compared include voltage stress of switching components, output voltage regulation, transient response due to a step-load, and efficiency. Test results show that, while the two converters exhibit equal performance on output voltage regulation, the two-switch forward converter has a lower voltage stress on power switching devices, faster transient response, and higher efficiency than the RCD clamp forward converter.
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Simple level control plant model using LabVIEW
(2018-01-06)
Rerkratn, Apinai
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Luangpol, Amata
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Prasitmeeboon, Pitcha
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Petchmaneelumka, Wandee
This paper presents a design and implementation of water level control plant model used as learning aid in the level control process. The plant model consists of a differential pressure transmitter, Frequency Inverter and Proportional-Integral-Derivative (PID) Controller. The differential pressure transmitter is used for measuring liquid level in process tank, and Inverter is employed to adjust the inlet flow of the tank. The PID controller can be configured by a PID function of LabVIEW program. In addition, two flow transmitters and solenoid valve are also installed to monitor the flow rate and/or cascade additional control loop in the future. The procedure to implement the plant model are divided into 5 steps: Controlling liquid level in cylinder tank with 10 cm in diameter and 40 cm in height were specified, sizing and selecting instruments needed, implementing the plant model according to the designed Piping & Instrument (P&I) diagram and Solid Work drawing, designing the control program and human machine interface (HMI) screen in LabVIEW program and the control parameters for single-loop controller modeled TTM-007, and evaluating the performances of implemented plant model. The experimental results of step changes of set point are also included and compared to the result from the plant using a commercially available single loop controller.

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