Direct driven hydraulic drive for new powertrain topologies for non-road mobile machinery

• Published in: Electric power systems research Vol. 152; pp. 390 - 400
• Main Authors: Minav, T.A., Heikkinen, J.E., Pietola, M.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-11-2017; Elsevier Science Ltd
• Subjects: Angular speed; Batteries; Cylinders; Direct driven hydraulics; Drive; Electric power; Energy efficiency; Hydraulic control; Hydraulics; Machinery; Machinery and equipment; Non-road mobile machinery; Power efficiency; Powertrain; Servomotor; Topology; Variable speed drive control; NRMM; Non-road mobile machinery; Hydraulics; SOC; DDH; Drive; Variable speed drive control; Energy efficiency; Topology; Direct driven hydraulics; Servomotor
• ISSN: 0378-7796; 1873-2046
• DOI: 10.1016/j.epsr.2017.08.003

•Evaluation of direct driven hydraulic drive usage for NRMM application.•Detailed analysis based on Sankey diagrams of the powertrain topologies.•DDH benefits electric powertrain without needs of conventional control valves.•174% improvement of efficiency by converting a conventional NRMM to electric topology.
Tightening of emission rules and a desire to improve energy efficiency pushes even further the need for hybridization of non-road mobile machinery (NRMM). Consequently, this paper illustrates potential of the application of directly driven hydraulic drive (DDH) for NRMM from an energy efficiency point of view. The control of the DDH system was implemented directly with a servomotor driving a pump without conventional hydraulic control valves. Angular speed of the servomotor, in-coming oil flow from the pump, and out-going flow to the hydraulic motor determined the velocity of the double-acting cylinder piston. An earlier study by the authors presented that the hydro-mechanical losses were dominant in the original DDH setup. Resulting theoretical investigation indicated that the best scenario efficiency for DDH was estimated to be 76.7%. Therefore, this paper provides a detailed analysis based on Sankey diagrams of various powertrain topologies with DDH. This study of powertrains illustrated that DDH has the highest impact with 174% efficiency improvement with an electric NRMM powered by batteries instead of a conventional topology.