Energy efficient capacitor DC-DC converter for autonomous power supply system

Abstract

The main requirement for autonomous power supply systems is improved weight-size and energy parameters. A promising way to solve this problem is to use DC-DC converters based on resonant structures with switched capacitors. Improvement of energy indicators of the converter is achieved due to soft-switching mode of semiconductor elements providing reduction of dynamic power losses and increasing the level of the primary source. Improvement of weight-size parameters of the converter is provided due to the following: multi-cycle principle of the design providing a significant increase of frequency conversion up to several hundred kHz due to multiple reduction of installed capacity of semiconductor elements; high specific energy indicators of modern multilayer ceramic capacitors, more than two orders of magnitude higher than similar indicators of reactors and transformers; optimization of parameters of semiconductor and reactive elements, which also contributes to significant reduction of weight and volume of power supply systems. The authors have conducted the analysis of weight-size parameters of the step-up DC-DC converter and the value of its efficiency under the assumption of proportionality of weight and volume of reactive converter elements to the maximum accumulated energy and proportionality of weight and volume of semiconductor elements to their installed capacity. The authors have proposed and studied the circuit of multipolar DC-DC converter based on structures with switched capacitors, which has the space symmetry. The space symmetry provides a significant improvement of weight-size parameters due to two-fold reduction of the total installed capacity of semiconductor elements. The volume and energy indicators of the converter under study as a part of power supply system have been evaluated. A method to design a power circuit of a capacitor converter with improved energy and weight-size parameters as a part of an autonomous power supply system is proposed. The authors have established the most effective ways to improve the weight-size and energy indicators of DC voltage converters. The improvement of weight-size parameters is achieved due to a twofold reduction of the installed capacity of semiconductor elements and optimization of the parameters of reactive elements. Improvement of energy indicators is achieved due to increasing the input voltage level of the converter and soft switching of its semiconductor elements.