Title:Two Basic Concepts of Hydraulic Switching ConvertersAuthor(s):Helmut Kogler, Rudolf ScheidlAbstract:Hydraulic switching control attempts to transfer concepts from modern electrical drive control to hydraulics. Both, electrical and hydraulic switching systems can achieve higher efficiency than resistance control. In this paper, the hydraulic pendants of the electrical Buck-Converter and Cuk-Converter are introduced. Basically, the hydraulic switching converters consist of switching elements (fast valves), inductances and capacities. The active valves are typically switching at a certain frequency in PWMmode. The Buck-Converter is a traditional step down converter, so the pressure at the load is always lower than the supply pressure. The concept of the Cuk-Converter even allows to boost the load pressure up to a higher level than the available supply pressure. But it is much more difficult to realize the hydraulic switching converters than their electrical pendants. The wave propagation in the fluid, the impossibility to realize a pure inductivity and the nonlinearities of the hydraulic elements are major difficulties. This paper gives an idea of the basic converter concepts and the difficulties concerning the realization of such drives. Further the results of simulations and measurements are presented.Booktitle:Proceedings of the First Workshop on Digital Fluid Power, 3rd October 2008, Tampere, FinlandEditor(s):M. Linjama and A. LaamanenISBN:978-952-15-2037-2Page Reference:page 113-128, 16 page(s)Publishing:10/2008