Analogy Between Hydraulic Transformers and Variable-speed Pumps

Lasse Schmidt, Søren Ketelsen, Robin Mommers, Peter Achten

Publikation: Bidrag til bog/antologi/rapport/konference proceedingKonferenceartikel i proceedingForskningpeer review

2 Citationer (Scopus)


The increasing focus on energy efficient systems and energy recuperation functionalities calls for multi actuator hydraulic systems to be tightly integrated with regards to energy distribution. Such systems need to allow power to pass back and forth between loads and the supply, while also enabling the ability to store energy. Here two approaches are obvious; namely the usage of hydraulic transformers interconnected via common pressure rails containing accumulators, and variable-speed pumps interconnected via a common electric dc-bus containing capac-itors and/or batteries, both having the potential for energy storage and power sharing. A main question is when to apply which of these technologies, when considering specific requirements to actuator dynamics and control features. This paper presents an investigation into the analogy between hydraulic transformers and variable-speed pumps. The investigation takes offset in model based analyses of these technologies regarding their actuation dynamics related to torque generation, input-to-output pressure dynamics with and without a cylinder load. Finally a numerical study is presented, verifying and comparing their transient characteristics and energy losses. It is found that, disregarding the conventional speed control loop in variable-speed pumps, these are in fact equivalent with hydraulic transformers regarding secondary control abilities, dynamics and energy recovery, whereas hydraulic transformers generally must be expected to be more efficient than variable-speed pumps.
TitelProceedings of the 2020 Bath/ASME Symposium on Fluid Power and Motion Control
ForlagAmerican Society of Mechanical Engineers
Publikationsdatosep. 2020
ISBN (Elektronisk)978-0-7918-8375-4
StatusUdgivet - sep. 2020
BegivenhedBATH/ASME 2020 Symposium on Fluid Power and Motion Control, FPMC 2020 - Virtual, Online
Varighed: 9 sep. 202011 sep. 2020


KonferenceBATH/ASME 2020 Symposium on Fluid Power and Motion Control, FPMC 2020
ByVirtual, Online
SponsorFluid Power Systems and Technology Division


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