Design of interleaved multilayer Rosen type piezoelectric transformer for high voltage DC/DC applications

Abstract

Research and development within piezoelectric transformer (PT) based converters are rapidly increasing as the technology is maturing and starts to prove its capabilities. Especially for high voltage and high step-up applications, PT based converters have demonstrated good performance and DC/AC converters are widely used commercially. The availability of PT based converters for DC/DC applications are very limited and are not that developed yet. I this paper an interleaved multi layer Rosen-type PT for high step-up and high output voltage is developed, for driving a 2.5kV dielectric electro active polymer actuator [17]. The targeted application utilises an inductor-less half-bridge driving topology, where the reward of eliminating the series inductor is a reduction in component count, size and price. The absence of a series inductance calls for other means to avoid large hard switching losses and obtain soft switching capabilities. This can be achieved by utilising an advantageous PT structure, which is the main advantage of the interleaved Rosen-type PT. Furthermore the design should be further optimised, in order to achieve soft switching capability. The goal of this paper is to develop a soft switching optimised PT, capable of generating output voltages higher than 2kV from a 24V supply voltage. Furthermore finite element method (FEM) has been the main tool through the PT development.

Empiric analysis of zero voltage switching in piezoelectric transformer based resonant converters

“…The prototype PT is of the same design as the one simulated [14], with the exception of a bit different polarisation, which divides the turn's ratio (n) by two. Its properties are listed in Table 4 and Table 5, and as it can be seen it possesses a quit high ZVS factor.…”

“…The derivation is based on a series of parametric sweep time domain PSpice simulations of the inductor-less half-bridge, where the figures of Table 1 are the used lumped parameters. The figures origins from the interleaved multi layer Rosen-type PT design presented in [14], but as the lumped parameter mode is independent of PT design, the results should be general. The simulations have been preformed with at least 100 cycles before any measurements were made, in order to insure steady-state operation.…”

“…From Equation (1) the ZVS factor of [12] can be calculated, as well as the match load and efficiency [12] [14], as well as the resonance frequency. And as it can be seen from Table 2, the design possesses a ZVS factor which is sufficient to achieve soft switching.…”

Piezoelectric Direct Discharge: Devices and Applications

“…Especially important for plasma applications are the high power high voltage RPTs. An optimized multilayer structure enables the RPT with a maximum power transfer [19] and a high voltage transformation ratio [20,21]. Further efforts are made to develop a lead-free RPT.…”