On the Unstationary response Dynamics of the Hydraulic Resonance Converter
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Proc. 7th Scandinavian Internat. Conference on Fluid Power, SICFP’01
The hydraulic resonance converter utilizes the dynamics of an oscillating piston which is operated close to its natural frequency to provide switching type control for hydraulic drives. Its transient dynamics is investigated in this paper by means of point maps.
First, its operation in a so called ‘frequency controlled mode’ acting on a plunger cylinder is investigated by a simple linear mathematical model. The point map yields a four dimensional, linear discrete dynamical system. It has a unique, globally stable fixed point, which corresponds to the steady state operation of the drive system. The transient behavior is described by the eigenvalues of the point map. Limitations in this mode stem from its steady state performance characteristics that is from its behavior at the fixed point of the point map.
In a second mode of control, the ‘power controlled mode’ a nonlinear one dimensional point map arises if the dynamic coupling of the converter with the driven system is disregarded. A fast control concept for this operational mode is derived. It renders step like pressure and flow rate changes within one or a few switching cycles possible.