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The Study of Polarization and Depolarization Current Measurements on Service-Aged 22 kV XLPE Underground Cables with Presence of Water Trees
(2022-01-01)
Udomluksananon, P.
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Kunakorn, A.
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Maneerot, S.
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Bunlaksananusorn, C.
;
Pannil, P.
This paper represents the condition assessment of service-aged 22 kV XLPE insulated underground cables. From the investigation, the water trees were detected in the insulation layer. The visual inspection of underground cables reveals the presence of copper carbonate contaminated on the copper tape layer. Some underground cables have the discontinuity of the copper tape layer. To evaluate the insulation condition of the underground cables, the polarization and depolarization current (PDC) measurements were performed on both the service-aged and the new (or unused) cables. The underground cables to experiment with the length of insulation screen equal to 1 m were prepared. In this research, the PDC measurements were performed on different aspects, i.e., the testing voltages (600 V, 800 V, and 1000 V), the testing positions, the effect of the discontinuity of the copper tape layer which occurred during service, the influence of the presence of copper carbonate, and the influence of water trees in XLPE cables. The dielectric response of the underground cables by using polarization and depolarization current measurements can diagnose the problems in service-aged underground cables, but this paper needs more test data for accurate interpretation.
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Experimental study of a vibration based energy harvesting system for an RFID module
(2018-07-02)
Khemmanee, B.
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Tattiwong, K.
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Bunlaksananusorn, C.
In recent years, an application of a piezoelectric transducer to harvest energy from ambient vibrations has been a subject of intense research. As the material technology advances, the amount of energy being able to produce by the transducer continues to increase. This paper presents an experimental study of a vibration based energy harvesting system for an RFID module. The system consists of a piezoelectric transducer, a power management circuit based on a buck converter, and an RFID module. The transducer converts mechanical movement produced by a finger press into a voltage to charge an input capacitor. The buck converter then converts the input capacitor voltage into a stable DC output voltage to power the RFID module. Experimental results are presented to validate the performance of the proposed energy harvesting system.
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Analysis design and experimental verification of a two-switch forward converter
(2015-12-01)
Wuti, V.
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Bunlaksananusorn, C.
A forward converter is an isolated DC-DC converter widely used in switching power supplies with output power ratings ranging from 50W to 400W. The conventional forward converter requires a transformer with a tertiary winding to assist in magnetic core reset and subjects its power switch to a high voltage at turn-off. These shortcomings are eliminated in the two-switch forward converter. This paper presents analysis, design and experimental verification of a two-switch forward converter. First, the converter operation is analyzed, enabling its key equations and important waveforms to be established. Then, the converter design, including both the power circuit and feedback controller, is illustrated in detail. Finally, experimental results from the prototype circuit are presented to confirm the validity of the analysis and design.
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Analysis design and experimental verification of a quadratic boost converter
(2015-01-26)
Tattiwong, K.
;
Bunlaksananusorn, C.
This paper presents analysis, design and experimentation of a Quadratic Boost Converter (QBC). Operation of the QBC is analyzed, leading to mathematical expressions that can be used to design the converter. Based on the derived analytical expressions, a 100W, 12V-to-48V, QBC converter is designed and built. Experiment shows that the prototyped converter operates satisfactorily throughout its operating range and achieves the highest efficiency of 83%.
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Improving output performance of a two-switch forward converter with a lead-lag controller
(2015-01-26)
Wuti, V.
;
Bunlaksananusorn, C.
This paper presents improvement of an output performance of a two-switch forward converter with a Lead-Lag (LL) controller. The controller design is illustrated and its ability to regulate the converter's output voltage is evaluated experimentally. It is revealed that the converter employing the LL controller can achieve a higher system bandwidth compared to that employing the Proportional-plus-Integral (PI) controller, therefore exhibiting a faster output voltage response.
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Design and implementation of an integrated boost-flyback converter
(2015-01-01)
Tattiwong, K.
;
Bunlaksananusorn, C.
This paper presents design and implementation of a Integrated boost-flyback converter (IBFC). Operation of the IBFC is described and its key voltage and current equations are given. The practical design of a 96W, 12V-to-48V, IBFC is demonstrated. Experiment on the prototype IBFC shows that it operates with good output voltage regulation and achieves the highest efficiency of 87%.
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Feedback compensator design for a two-switch forward converter
(2012-12-01)
Wuti, V.
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Kerdpol, T.
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Bunlaksananusorn, C.
Advantages of a two-switch forward converter over its single-switch counterpart are that it operates with reduced voltage stress on power semiconductor switches and does not require a transformer with a reset winding. The lower stress on the switching devices leads to increased reliability and, without the reset windings, the transformer production is simplified. In this paper, feedback compensator design for a two-switch forward converter is presented. A Proportional-plus-Integral (PI) compensator is chosen for its simplicity. Experimental results confirm that the properly designed PI compensator is capable of providing the satisfying output voltage regulation and transient response. © 2012 IEEE.
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Modeling and control of a zeta converter
(2010-09-17)
Vuthchhay, E.
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Bunlaksananusorn, C.
A Zeta converter is a fourth-order DC-DC converter made up of two inductors and two capacitors and capable of operating in either step-up or step-down mode. Compared with other converters in the same class, such as Cuk and SEPIC converters, the Zeta converter has received the least attention, and more importantly, its dynamic modeling and control have never been reported before in the literature. This paper presents dynamic modeling and control of a Zeta converter operating in Continuous Conduction Mode (CCM). The State-Space Averaging (SSA) technique is applied to find small-signal linear dynamic model of the converter and its various transfer functions. Based on the derived control-to-output transfer function, the PWM feedback controller is designed to regulate the output voltage. Results show that the converter exhibits good performance in steady state and during a step-load change. © 2010 IEEE.
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Improvement of output dynamic performance of an average current mode controlled buck converter with a parallel controller
(2010-09-17)
Chrin, P.
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Trakuldit, S.
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Polmai, S.
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Bunlaksananusorn, C.
This paper presents a parallel voltage controller to improve the output dynamic performance of a buck converter with Average Current Mode Control (ACMC). The parallel controller is a high-order controller synthesized from parallel connection of the two basic controllers. It is proposed to compensate the control-to-output transfer function of the converter, which has multiple poles and zeros. Up until now, the task is commonly performed by the two-pole one-zero controller, which is clearly not adequate and has somewhat limited the dynamic performance of the converter. In the paper, the design of parallel controller is illustrated with a 5V/2V ACMC buck converter. Experimental and simulated results that show the improvement of output voltage response to a step load change are presented. © 2010 IEEE.
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Dynamic modeling and control of a zeta converter
(2008-12-01)
Vuthchhay, E.
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Bunlaksananusorn, C.
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Hirata, H.
A Zeta converter is a fourth-order dc-dc converter made up of two inductors and two capacitors and capable of operating in either step-up or step-down mode. Compared with other converters in the same class, such as Cuk and Sepic converters, the Zeta converter has received the least attention, and more importantly, its dynamic modeling and control have never been reported before in the literature. This paper presents dynamic modeling and control of a Zeta converter. The State- Space Averaging (SSA) technique is applied to find small-signal linear dynamic model of the converter, whereby various transfer functions of the converter can be determined. Based on the control-to-output transfer function, the compensator in PWM feedback loop can be designed to regulate the output voltage. Simulation results show that the converter exhibits good performance during a start-up and step load change. © 2008 IEEE.

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