This paper presents a design process of a hydraulic step-down switching converter considering the load losses in the inertance tube and switched valve. A steady state analysis for the switching converter as well as nonlinear dynamic simulation results of a digital hydraulic position and speed control system are presented. The results using the steady state and dynamic models are validated by experimental results obtained using a hydraulic test bench able to apply different loads to the system. The results show that steady-state model provides a very good approach to perform the preliminary design of hydraulic switching converters. The impact of tube parameters in the system efficiency is also discussed.
Keywords: Digital hydraulics, Hydraulic step-down converter, PWM switched valve