Development of Improved Performance Switchmode Converters for Critical Load Applications

Pattnaik, Swapnajit (2011) Development of Improved Performance Switchmode Converters for Critical Load Applications. PhD thesis.



Emerging portable applications and the rapid advancement of technology have posed rigorous challenges to power engineers for an efficient power delivery at high power density. The foremost objectives are to develop high efficiency, high power density topologies such as: buck, synchronous buck and multiphase buck converters, with the implementation of soft switching technology to reduce switching losses maintaining voltage and current stresses within the permissible range. Demand of low voltage power supply for telecom system leads to narrow duty cycle which compels to increase operating switching frequency. Design of conventional buck converter under narrow duty cycle is quite objectionable since it leads to poor utilization of components as well as it degrades the system efficiency. A high switching frequency operation reduces the switch conduction time that leads to large increase in switching losses and increases the control complexity. Therefore, duty cycle has to be extended and at the same time switching losses have to be minimized. Transformer based topology can be used to extend the duty cycle. But to reduce switching losses soft switching techniques should be implemented. An isolated buck converter with simple clamp capacitor scheme is proposed to reduce switching losses and to extend duty cycle by optimizing the turn ratio. Extended duty cycle impose limit on dead time. Dead time has to be controlled with respect to duty cycle to reduce body diode conduction loss and to avoid the shoot through conditions in our proposed topology. The proposed clamp capacitor scheme control the dead time as well as provide better efficiency with reduction in switching losses maintaining ripples within the allowable range.

Item Type:Thesis (PhD)
Uncontrolled Keywords:Soft Switching Technology; Buck Converters; Semiconductor Devices
Subjects:Engineering and Technology > Electrical Engineering > Power Systems
Engineering and Technology > Electrical Engineering > Power Electronics
Divisions: Engineering and Technology > Department of Electrical Engineering
ID Code:3009
Deposited By:Hemanta Biswal
Deposited On:01 Feb 2012 15:02
Last Modified:13 Jun 2012 17:03
Supervisor(s):Panda, A K and Mahapatra, K K

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