Title :
Parameterized analysis of Zero Voltage Switching in resonant converters for optimal electrode layout of Piezoelectric Transformers
Author :
Meyer, Kaspar Sinding ; Andersen, Michael A E ; Jensen, Flemming
Author_Institution :
Tech. Univ. of Denmark, Lyngby
Abstract :
Ring shaped PTs (piezoelectric transformers) are an attractive alternative to magnetics in power converters. The achievable energy efficiency is 98% and the power density is up to 30 W/cm3. Additionally power supplies based on PTs display low levels of conducted and radiated EMI due to power conversion based on the piezoelectric effect. Rooted in the physics of this effect, both the in- and output terminal of a PT has a noticeable parasitic capacitance. In a common half-bridge power stage without any supporting magnetic components, the input parasitic capacitance can lead to hard switching losses that are in the range of the actual power rating of a specific PT. In this paper it is demonstrated how the electrode layout of a PT can be designed to enable ZVS (zero voltage switching). This optimization is made simple with a novel set of accurate and simple symbolic equations which relates ZVS constraints to the physical electrode layout of a PT. These properties takes basis in the formulation of an equivalent electrical PT circuit that is valid around the frequency of operation.
Keywords :
piezoelectric devices; resonant power convertors; switching convertors; transformers; zero voltage switching; PT; optimal electrode layout; optimization; piezoelectric transformer; power converters; resonant converters; symbolic equations; zero voltage switching; Displays; Electrodes; Energy efficiency; Magnetic analysis; Magnetic resonance; Parasitic capacitance; Power supplies; Switching converters; Transformers; Zero voltage switching;
Conference_Titel :
Power Electronics Specialists Conference, 2008. PESC 2008. IEEE
Conference_Location :
Rhodes
Print_ISBN :
978-1-4244-1667-7
Electronic_ISBN :
0275-9306
DOI :
10.1109/PESC.2008.4592323