Designing an Electro-Hydraulic Control Module for an Open-Circuit Variable Displacement Pump

This paper deals with the problem of designing an electric control module for a Sauer-Danfoss Series 45 H-frame open circuit axial piston pump. The purpose of the electric control module is to replace the existing hydro-mechanical (LS) regulator, and enable the pump to follow a reference pressure, in the form of an electric control signal, under varying working conditions, when having access to engine speed and actual pump pressure. The paper presents a model of both the pump and the control module, along with design considerations on which linear controllers are developed for a worst point consideration. Based on the initial topology experimental results are presented and a simulation comparison is made with the original hydro-mechanical controlled pump. Based on these results, improvements for a second prototype are presented along with a simulation result for this.