Methodologies for the design of LCC voltage-output resonant converters

Abstract-Soft switching is required to attain high efficiency in high-frequency power converters. Piezoelectric transformerbased converters can benefit from soft switching in terms of significantly diminished switching losses and stresses. Adequate dead time is needed in order to deliver sufficient energy to charge and discharge the input capacitance of piezoelectric transformers in order to achieve zero-voltage switching. This paper proposes a method for detecting the optimum dead time in piezoelectric transformer-based switch-mode power supplies. The provision of sufficient dead time in every cycle of the switching period results in the quick start up of resonant current inside the transformer. The new method is implemented by dynamically detecting the optimum dead time for each resonant cycle and results in reduced energy loss, and consequently, increased efficiency in the converter during initialization time and steady-state operation. The theory of optimum dead time operation is also discussed in this paper. Experimental results and simulation are provided to show the implementation of the concept.

Section: A Principle Of Dead Time (Dt)mentioning

confidence: 99%

Dynamic Optimum Dead Time in Piezoelectric Transformer-Based Switch-Mode Power Supplies

Ekhtiari

Andersen

et al. 2017

“…Over one half-cycle (14) Substituting for and rearranging provides (15) A further expression for can be obtained by noting that the rectifier ceases conducting when . Evaluating the preceding expression and rearrangement leads to (16) The output voltage is subsequently found from Ohm's law: .…”

Section: B Operation With Discontinuous Conductionmentioning

confidence: 99%

“…It is therefore prudent to give boundaries of model applicability. Due to significant complexity involved in determining these boundaries, a similar technique to that reported in [14], is taken, where many randomly generated converter designs are simulated using accurate timedomain based models, the results of which are used to validate the describing function models over a wide parameter range. Notably, the normalized design parameters are used, thereby providing generically applicable results for a wide range of converter specifications.…”

Section: Model Boundariesmentioning

confidence: 99%

“…A similar technique has previously been successfully applied to model the LCC voltage-output converter [11]- [14] and the LCC current-output converter operating under heavy load conditions [15]. The presented analysis is based on an approximate model for the CLL converter previously reported in [16] where the waveform shape of is approximated by a half-wave rectified sinusoid with dead-periods.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Analysis of CLL Voltage-Output ResonantConverters Using Describing Functions

Foster

Gould

Gilbert

et al. 2008

Abstract-A new ac equivalent circuit for the CLL voltageoutput resonant converter is presented, that offers improved accuracy compared with traditional FMA-based techniques. By employing describing function techniques, the nonlinear interaction of the parallel inductor, rectifier and load is replaced by a complex impedance, thereby facilitating the use of ac equivalent circuit analysis methodologies. Moreover, both continuous and discontinuous rectifier-current operating conditions are addressed. A generic normalized analysis of the converter is also presented. To further aid the designer, error maps are used to demonstrate the boundaries for providing accurate behavioral predictions. A comparison of theoretical results with those from simulation studies and experimental measurements from a prototype converter, are also included as a means of clarifying the benefits of the proposed techniques.

“…The voltage-output LCC resonant converter ( Fig. 1), while having good part-load efficiency characteristics, is difficult to analyse as a result of the finite time taken to charge and discharge the parallel capacitor [5]- [9]. Fundamental Mode Approximation (FMA), the most widely used technique for analysis, assumes that the parallel capacitor waveform is a square-wave, which 0885 can significantly degrade analysis accuracy.…”

mentioning

confidence: 99%

Normalized Analysis and Design of LCC Resonant Converters

Gilbert

Bingham

Stone

et al. 2007

Abstract-A normalization of the LCC voltage-output resonant converter performance characteristics, in terms of the tank gain at resonance and the parallel-to-series-capacitor ratio, is presented. The resulting description is subsequently used for the derivation of a design procedure that incorporates the effects of diode losses and the finite charge/discharge time of the parallel capacitor. Unlike previously reported techniques, the resulting normalized behavior of the converter is used to identify design regions to facilitate a reduction in component electrical stresses, and the use of harmonics to transfer real power. Consideration of the use of preferred component values is also given. The underlying methodology is ultimately suitable for incorporation into a software suite for use as part of a rapid interactive design tool. Both simulation results and experimental measurements from a prototype converter are included to demonstrate the attributes of the proposed analysis and design methodologies.