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Payyappilly B.,Power Systems Group | John V.,Indian Institute of Science
2014 IEEE International Conference on Power Electronics, Drives and Energy Systems, PEDES 2014 | Year: 2014

Primary side flyback PWM controllers are available with large number of protection features such as over current protection, over/ under input voltage protection, over output voltage protection etc., and designs using such controllers can be cost effective. They are designed for flyback dc-dc converters for low power CV-CC applications like LED lighting and mobile/PDA battery chargers. Using this type of controllers for a Buck type CV-CC battery charger, which can be designed for higher power levels is a low cost option. It offers accurate CV-CC control function with a stable change over between constant current and constant voltage regimes. It is shown that the resulting design can fully utilize the protection features, which increases safety and reliability. This paper presents the design of a 14V, 7W CV-CC battery charger using such an integrated controller and explains the modifications required for the flyback controller to work as a buck CV-CC charger. © 2014 IEEE. Source

Rahman N.A.A.,Power Systems Group | Marican A.M.A.,DCS Engineering Sdn Bhd
2010 International Conference on High Voltage Engineering and Application, ICHVE 2010 | Year: 2010

A 132/33kV substation has been analysed in terms of touch and step potentials at the fence. A review of the relevant standards is conducted. The touch and step potentials at the fence are calculated using a computer model and an alternative fence earth treatment has been proposed. The recommendations given from the analysis conducted can be further explored in terms of practicality and necessity in ensuring that the substation fence is safe to the general public. ©2010 IEEE. Source

Mehta B.K.,Indian Institute for Plasma Research | Deshpande S.,Indian Institute for Plasma Research | Mukherjee S.,Indian Institute for Plasma Research | Puthanveettil S.E.,Power Systems Group
Journal of Spacecraft Technology | Year: 2011

Spacecrafts with high voltage power system are more prone to suffer from charging and arcing damage in the geomagnetic sub-storm environment, due to interaction with energetic plasma. This occurs due to factors like the presence of different surface materials or due to different illumination conditions like the presence or absence of sunlight. Precise knowledge of material characteristics and plasma environment are important parameters to understand this phenomenon. For spacecrafts where many materials are used for specific requirements, with conditions like altitude and plasma environment varying, prediction of charging condition becomes difficult. Experimental simulations can be expensive and therefore, there is a need to develop adequate numerical simulation models. This article presents the theory of spacecraft charging in Geosynchronous Earth Orbit (GEO), which requires detailed knowledge about plasma environment, charging process and spacecraft geometry. Floating potential and equilibrium potential by current calculation for various materials for spherical geometry in normal Maxwellian plasma and worst case Maxwellian plasma environment has been studied using POS (Patch on Sphere) model. The results have been validated with well established charging model and extrapolation to experiments related to arcing. Source

Teninge A.,Grenoble Institute of Technology | Roye D.,Power Systems Group | Roye D.,Ecole Polytechnique - Palaiseau | Bacha S.,Power Systems Group | Bacha S.,Joseph Fourier University
19th International Conference on Electrical Machines, ICEM 2010 | Year: 2010

This paper is dealing with the reactive power management of two kinds of variable speed wind turbine (WT) technologies in order to respect the grid code requirements during voltage dips. Nowadays, the WT systems are asked to fulfil with many grid connection requirements, especially to provide reactive power during dip voltage with the aim of better voltage recovering. Specific controls applied to Double Fed Induction generator WT (DFIG) and Permanent Magnet Synchronous Generator fully interfaced (PMSG) are proposed in this paper to meet with these requirements. The control laws are studied through simulations; results analysis shows their efficiency and their limits. ©2010 IEEE. Source

Chaitanya B.S.,Thermal Systems Group | Sankaran M.,Power Systems Group | Bindagi S.V.,Thermal Systems Group | Barve S.G.,Thermal Systems Group | Sharma A.K.,Thermal Systems Group
Proceedings - International Symposium on Discharges and Electrical Insulation in Vacuum, ISDEIV | Year: 2014

Arcing in spacecraft is a well known phenomenon in the Aerospace industry. Generally, the only signature in the spacecraft telemetry when an arcing event takes place is the current drawn in to the arc from the power bus and the temperature of the affected and surrounding equipment. A method of simulating a vacuum electric arc for thermal modeling purpose was developed in the IDEAS platform. A simplified thermal model of electrical arc was developed to reproduce the thermal signature of an in orbit arcing event in thermal analysis. The electrical arc thermal simulation was carried out at various suspected arcing locations. The temperature signature from the analysis was compared with the actual/ hardware simulation results. This approach was used to identify the location of an electrical arc and its magnitude (power). Ground tests were also carried out and temperatures observed during the ground tests were used to validate the thermal model. This paper explains the methodology used and how this modeling principle was validated through measured data. © 2014 IEEE. Source

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