Dynamic Analysis & Characterization of Conventional Hydraulic Power Supply Units

Research output: Contribution to book/anthology/report/conference proceedingArticle in proceedingResearchpeer-review

1 Citation (Scopus)

Abstract

Hydraulic power units operated as constant supply pres-sure systems remain to be widely used in the industry, to supply valve controlled hydraulic drives etc., where the hydraulic power units are constituted by variable pumps with mechanical outlet pressure control, driven by induction motors. In the analysis of supplied drives, both linear and rotary, emphasis is commonly placed on the drives themselves and the related loads, and the supply system dynamics is often given only little attention, and usually neglected or taken into account in a simplified fashion. The simplified supply system dynamics used in such analyzes is often justified by short supply lines and/or the utilization of accu-mulators near valve inlets, accounting for the majority of possi-ble supply pressure variations. Such considerations are reason-able in many test benches, where the supply pressure variations are small enough such that limited impact on the drive dynamics is observed. Such ideal properties however, are not necessarily present in industrial hydraulic applications for various reasons, with the most common being large volumes of supply lines. Long supply lines, hence large supply line volumes, between the sup-ply system and drives will reduce the flow-to-pressure gain of the supply system, and hence increase the time constant of the sup-ply pressure dynamics. A consequence of this may be large vari-ations in the supply pressure, hence large variations in the pump shaft torque, and thereby the induction motor load torque, with possible excitation of the induction motor dynamics as a result. In such cases, the coupled dynamics of the pressure controlled pump and induction motor may influence the supply pressure sig-nificantly, possibly affecting the dynamics of the supplied drives, especially in cases where pilot operated valves with internal pi-lot supply are used. This paper is concerned with the analysis and characterization of the coupled pump-induction motor dy-namics, confined to hydraulic power units constituted by an axial piston pump with mechanical outlet pressure control, driven by an induction motor operated at grid conditions. Furthermore, a simplified general model representation of the coupled dynamics is established, accounting for the entire dominating dynamics of the supply unit. Results demonstrate the accuracy of the simpli-fied model representation.
Original languageEnglish
Title of host publicationProceedings of the BATH/ASME 2016 Symposium on Fluid Power and Motion Control
Number of pages10
PublisherAmerican Society of Mechanical Engineers
Publication dateSep 2016
Article numberFPMC2016-1756
ISBN (Print)978-0-7918-5006-0
DOIs
Publication statusPublished - Sep 2016
Event BATH/ASME 2016 Symposium on Fluid Power and Motion Control - Bath, United Kingdom
Duration: 7 Sep 20169 Sep 2016
http://www.bath.ac.uk/mech-eng/research/ptmc/symposium

Conference

Conference BATH/ASME 2016 Symposium on Fluid Power and Motion Control
CountryUnited Kingdom
CityBath
Period07/09/201609/09/2016
Internet address

Fingerprint

Dynamic analysis
Hydraulics
Induction motors
Pumps
Pressure control
Torque
Hydraulic drives
Reciprocating pumps
Loads (forces)
Industry

Keywords

  • Dynamic analysis
  • Dynamics (Mechanics)
  • Pressure
  • Electromagnetic induction
  • Motors
  • Pumps
  • Valves
  • Pressure control
  • Accounting
  • System dynamics

Cite this

Schmidt, L., Liedhegener, M., Bech, M. M., & Andersen, T. O. (2016). Dynamic Analysis & Characterization of Conventional Hydraulic Power Supply Units. In Proceedings of the BATH/ASME 2016 Symposium on Fluid Power and Motion Control [FPMC2016-1756] American Society of Mechanical Engineers. https://doi.org/10.1115/FPMC2016-1756
Schmidt, Lasse ; Liedhegener, Michael ; Bech, Michael Møller ; Andersen, Torben O. / Dynamic Analysis & Characterization of Conventional Hydraulic Power Supply Units. Proceedings of the BATH/ASME 2016 Symposium on Fluid Power and Motion Control. American Society of Mechanical Engineers, 2016.
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keywords = "Dynamic analysis, Dynamics (Mechanics), Pressure, Electromagnetic induction, Motors, Pumps, Valves, Pressure control, Accounting, System dynamics",
author = "Lasse Schmidt and Michael Liedhegener and Bech, {Michael M{\o}ller} and Andersen, {Torben O.}",
year = "2016",
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Schmidt, L, Liedhegener, M, Bech, MM & Andersen, TO 2016, Dynamic Analysis & Characterization of Conventional Hydraulic Power Supply Units. in Proceedings of the BATH/ASME 2016 Symposium on Fluid Power and Motion Control., FPMC2016-1756, American Society of Mechanical Engineers, BATH/ASME 2016 Symposium on Fluid Power and Motion Control, Bath, United Kingdom, 07/09/2016. https://doi.org/10.1115/FPMC2016-1756

Dynamic Analysis & Characterization of Conventional Hydraulic Power Supply Units. / Schmidt, Lasse; Liedhegener, Michael; Bech, Michael Møller; Andersen, Torben O.

Proceedings of the BATH/ASME 2016 Symposium on Fluid Power and Motion Control. American Society of Mechanical Engineers, 2016. FPMC2016-1756.

Research output: Contribution to book/anthology/report/conference proceedingArticle in proceedingResearchpeer-review

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AU - Schmidt, Lasse

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AU - Bech, Michael Møller

AU - Andersen, Torben O.

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N2 - Hydraulic power units operated as constant supply pres-sure systems remain to be widely used in the industry, to supply valve controlled hydraulic drives etc., where the hydraulic power units are constituted by variable pumps with mechanical outlet pressure control, driven by induction motors. In the analysis of supplied drives, both linear and rotary, emphasis is commonly placed on the drives themselves and the related loads, and the supply system dynamics is often given only little attention, and usually neglected or taken into account in a simplified fashion. The simplified supply system dynamics used in such analyzes is often justified by short supply lines and/or the utilization of accu-mulators near valve inlets, accounting for the majority of possi-ble supply pressure variations. Such considerations are reason-able in many test benches, where the supply pressure variations are small enough such that limited impact on the drive dynamics is observed. Such ideal properties however, are not necessarily present in industrial hydraulic applications for various reasons, with the most common being large volumes of supply lines. Long supply lines, hence large supply line volumes, between the sup-ply system and drives will reduce the flow-to-pressure gain of the supply system, and hence increase the time constant of the sup-ply pressure dynamics. A consequence of this may be large vari-ations in the supply pressure, hence large variations in the pump shaft torque, and thereby the induction motor load torque, with possible excitation of the induction motor dynamics as a result. In such cases, the coupled dynamics of the pressure controlled pump and induction motor may influence the supply pressure sig-nificantly, possibly affecting the dynamics of the supplied drives, especially in cases where pilot operated valves with internal pi-lot supply are used. This paper is concerned with the analysis and characterization of the coupled pump-induction motor dy-namics, confined to hydraulic power units constituted by an axial piston pump with mechanical outlet pressure control, driven by an induction motor operated at grid conditions. Furthermore, a simplified general model representation of the coupled dynamics is established, accounting for the entire dominating dynamics of the supply unit. Results demonstrate the accuracy of the simpli-fied model representation.

AB - Hydraulic power units operated as constant supply pres-sure systems remain to be widely used in the industry, to supply valve controlled hydraulic drives etc., where the hydraulic power units are constituted by variable pumps with mechanical outlet pressure control, driven by induction motors. In the analysis of supplied drives, both linear and rotary, emphasis is commonly placed on the drives themselves and the related loads, and the supply system dynamics is often given only little attention, and usually neglected or taken into account in a simplified fashion. The simplified supply system dynamics used in such analyzes is often justified by short supply lines and/or the utilization of accu-mulators near valve inlets, accounting for the majority of possi-ble supply pressure variations. Such considerations are reason-able in many test benches, where the supply pressure variations are small enough such that limited impact on the drive dynamics is observed. Such ideal properties however, are not necessarily present in industrial hydraulic applications for various reasons, with the most common being large volumes of supply lines. Long supply lines, hence large supply line volumes, between the sup-ply system and drives will reduce the flow-to-pressure gain of the supply system, and hence increase the time constant of the sup-ply pressure dynamics. A consequence of this may be large vari-ations in the supply pressure, hence large variations in the pump shaft torque, and thereby the induction motor load torque, with possible excitation of the induction motor dynamics as a result. In such cases, the coupled dynamics of the pressure controlled pump and induction motor may influence the supply pressure sig-nificantly, possibly affecting the dynamics of the supplied drives, especially in cases where pilot operated valves with internal pi-lot supply are used. This paper is concerned with the analysis and characterization of the coupled pump-induction motor dy-namics, confined to hydraulic power units constituted by an axial piston pump with mechanical outlet pressure control, driven by an induction motor operated at grid conditions. Furthermore, a simplified general model representation of the coupled dynamics is established, accounting for the entire dominating dynamics of the supply unit. Results demonstrate the accuracy of the simpli-fied model representation.

KW - Dynamic analysis

KW - Dynamics (Mechanics)

KW - Pressure

KW - Electromagnetic induction

KW - Motors

KW - Pumps

KW - Valves

KW - Pressure control

KW - Accounting

KW - System dynamics

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DO - 10.1115/FPMC2016-1756

M3 - Article in proceeding

SN - 978-0-7918-5006-0

BT - Proceedings of the BATH/ASME 2016 Symposium on Fluid Power and Motion Control

PB - American Society of Mechanical Engineers

ER -

Schmidt L, Liedhegener M, Bech MM, Andersen TO. Dynamic Analysis & Characterization of Conventional Hydraulic Power Supply Units. In Proceedings of the BATH/ASME 2016 Symposium on Fluid Power and Motion Control. American Society of Mechanical Engineers. 2016. FPMC2016-1756 https://doi.org/10.1115/FPMC2016-1756