Chancharoensook, Phop
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Preferred name
Chancharoensook, Phop
Alternative Name
Chancharoensook, P.
Main Affiliation
Email
phop.ch@kmitl.ac.th
19 results
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Item type:Publication, An improved asymmetric half-bridge converter for switched reluctance motor in low-speed operation with current regulated mode(2015-10-01); This study presents a novel method for reducing the switching losses of an asymmetric half-bridge converter for a three-phase, 12/8 switched reluctance motor operated in low speed. In particular, this study aims to reduce the switching-off losses of chopping switches in the converter when operated in the current regulated mode (chopping mode). The proposed method uses the mixed parallel operation of IGBT (chopping switch) and MOSFET (auxiliary switch). MOSFET is precisely controlled to momentarily conduct prior to the turn-off interval of the IGBT. Consequently, the voltage across the switches is clamped to approximately zero, substantially decreasing the turn-off switching losses. The analytical expressions of power losses are extensively elaborated. Compared with the conventional asymmetric half-bridge converter, the modified converter can effectively minimize the switching losses. Therefore, the efficiency of the converter is eventually improved. Computer simulation and experimental results confirm the effectiveness of the proposed technique. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, The Study and Analysis of Oil-immersed Power Transformer by Using Artificial Neural Network for Designing Program Apply in the Industry of Testing Oil-immersed Transformers(2020-10-25); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, The Effects of Coupling and Grounding on the Partial Discharge Pulse Propagation in the Underground Cable(2022-01-01); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Efficiency improvement of converter for switched reluctance motor drives at low speed operation(2009-12-01); This paper presents a method to improve the efficiency of a standard asymmetric half-bridge converter for 3 phase, 12/8 switched reluctance motor (SRM) drives at low speed operation. At that speed range, the SRM converter operates mainly in current chopping modes either hard chopping or soft chopping control. This work emphasizes on minimizing the main power losses during the turn-off interval of each cycle. Once the optimum size of snubber capacitor is obtained from calculation, such snubber capacitors are paralleled with chopping switches in order to reduce rate of voltage rise across those switches and ultimately their switching losses can be decreased. The developed dynamic model based on measured data of flux linkage and static torque characteristics of the SRM has been used for simulation in MATLAB/Simulink environment. The results have satisfactorily verified the validity of the proposed concept. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Partial Discharge Pulse Propagation in Coaxial Cable(2022-01-01); In the past, Coaxial cable was the signal cable used to transfer computer data. However, coaxial cables are now being modified for use in the high voltage coaxial cables to increase the security of power transmission in various areas. In addition to increased security, there is also an issue of stability maintenance and many perspectives as well. Because the cable that used to be utilized is still insulated. Therefore, Partial Discharge (PD) can still happen in the electrical system. This paper presents the PD propagation within the coaxial cable simulated via PSCAD/EMTDC program and carried out with RG-58 coaxial cable in a laboratory by testing the propagation of the PD pulse according to the conditions of different cable distances. From the experiment, the calculations will be reversed by considering on the differences of the time manner that PD pulse flows on the cable. The time reference point that the research studied has 2 points which are Peak to peak and Time of arrival(TOA). The comparison between simulation and experiment indicated the similar results with slight discrepancies caused by factors that can be accepted. TOA has smaller errors comparing with the peak to peak point showing that PD pulse flowing on the cable is attenuation and dispersion to the tailing wave part. That's the reason using Peak to Peak is a time reference point that has more errors. A thorough study of PD propagation is useful for in-depth analysis to locate the PD source accurately. As a result, the defect will be resolved on the spot. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Dielectric Loss Factor Measurement in A Gas-Insulated Transmission Line by Using Very Low Frequency Test(2020-06-01); Very low frequency tan delta measurement (VLF-TD measurement) is one of the insulation diagnosis methods usually uses to diagnosis the condition of electrical cable insulation. However, this research focuses on using VLF-TD measurement with a gas-insulated transmission line (GIL). The 230kV, 2500A, single phase, GIL with 2.0 m length was installed and prepared for experiments. in this paper, VLF-TD experiments were divided into 5 cases, classified by using types of artificial defects as a criterion, i.e. 1) The clean GIL without any defect, 2) The GIL with scratched on the surface of cone insulator, 3) The GIL with tracking path on the surface of cone insulator, 4) The GIL with protrusion on high voltage conductor and 5) The GIL with protrusion on enclosure. The average tan delta, VLF tan delta stability, and VLF differential tan delta were presented and compared in this paper. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Direct instantaneous torque control of a four-phase switched reluctance motor(2009-12-01)The paper presents an investigation on the direct instantaneous torque control (DITC) of a 1-hp four-phase 8/6 switched reluctance motor (SRM). In the proposed technique, the instantaneous phase torque was estimated in real-time using a pre-stored look-up table of measured static torque, T(i, X), where phase current and phase flux linkage were input parameters. Therefore, a high-resolution encoder can be avoided. The ripple-minimizing reference phase torques were generated from the torque distribution and commutation sequence controllers that use the knowledge of the reference total torque, rotor position information obtained from an inexpensive low-resolution encoder and the estimated phase torques. The fully digitalized closed-loop control consisted of effective and simplified PI controllers of phase torques, which straightaway gave the suitable PWM duty cycles to the IGBT-based asymmetric half-bridge converter. Obviously, the instantaneous torque of the SRM was directly controlled by continuously variable phase voltages without including any inner current control loop. Results obtained from computer simulations of the developed MATLAB/Simulink model and the DSP-based real-time control experiments have confirmed the validity and acceptable performance of the proposed scheme. Good step torque responses and good tracking abilities to various torque reference waveforms have been presented. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Control of a 3-Phase 12/8 Switched Reluctance Generator for Future Energy System Applications(2024-01-01)This paper presents implementation of a control system for a 3-phase 12/8 switched reluctance generator (SRG). The study has confirmed the potential of switched reluctance machines to be decent alternatives in renewable energy applications, energy storage systems and electrified transportation systems. Initially, a dynamic model of the SRG was created in MATLAB/Simulink environment to achieve useful preliminary results from computer simulation. Next, in hardware realization, the proposed system employed a standard asymmetric half-bridge (AHB) converter to generate a voltage of 200 V at the DC-link. Optimal turn-on and turn-off angles of phase current waveforms were used through commutation signals generated by a simple and inexpensive opto-interrupter rotor position sensor. There were two closed-loop controls involved in the system. The outer loop was for DC-link voltage control using PI controller while the inner loop was for phase current control using soft chopping hysteresis control technique. Finally, real-time control was implemented using an economical dsPIC30F4011 microcontroller. Experimental results have shown acceptable performance of the proposed SRG control system in various conditions, including normal operation, speed change and step reference voltage change. The DC-link voltage can be satisfactorily regulated when subjected to those conditions.1 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Efficiency improvement of converter for switched reluctance motor drives by mixed parallel operation of IGBT and MOSFET(2010-12-01); This paper presents a method to improve the efficiency of a standard asymmetric half-bridge converter for 3-phase, 12/8 switched reluctance motor (SRM) drives at low speed operation. At that speed range, the converter operates mainly in current chopping modes. The proposed method employs mixed parallel operation of IGBT/MOSFET pairs. The technique is aiming for minimizing the turn-off switching losses of IGBT which are the main chopping switches. MOSFET are placed in parallel with each IGBT in order to momentarily conduct the phase current during IGBT's turn-off intervals. While the MOSFET is on, the voltage across the IGBT is close to zero resulting in substantially decreased turn-off loss. Those fast switching MOSFET later instantaneously turn-off the current with almost lossless. The algorithm is verified by computer simulation and experimental results. The results have satisfactorily shown validity of the proposed concept. Furthermore, performance of the proposed strategy is superior to those of the typical hard switching technique and the conventional soft switching scheme using optimum sized snubber capacitors. ©2010 IEEE.1 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Test Chamber Designed with Temperature Control for Partial Discharge and Polarization and Depolarization Current Testing(2020-10-25); This paper presents the temperature-controlled test chamber for Partial Discharge and Polarization and Depolarization Current test of dielectric liquid including impregnated pressboards with the various conditions. Besides, the temperature of the test specimen is controlled between room temperature to 300°C. The temperature distribution in the test chamber was simulated. Besides, the electric field stress at the electrodes were simulated. Furthermore, different kinds of sensors such as a thermocouple, gas sensors, and so on were designed to be equipped within the test chamber. From the simulated result, both electric field stress and temperature distribution were in the given conditions.2