A closed circuit electro-hydraulic actuator with energy recuperation capability

Qu, Shaoyang; Fassbender, David; Vacca, Andrea; Busquets, Enrique; Neumann, Uwe

doi:10.25368/2020.16

Cited by 10 publications

(10 citation statements)

References 4 publications

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“…However, this issue is not new and well known for other pumpcontrolled concepts. In [12], it was proposed to install a proportional bypass valve in order to reduce the amount of returning flow at the hydraulic unit of an EHA during retraction. Such a bypass valve could be installed in parallel to the hydraulic motor in the novel concept as well if the high return line flow cannot be handled otherwise.…”

Section: Increased Flowsmentioning

confidence: 99%

Improving the Energy Efficiency of Single Actuators with High Energy Consumption

Fassbender¹,

Minav²,

Brach³

et al. 2021

Linköping Electronic Conference Proceedings

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A load sensing (LS) supply in combination with control valves is one of the most common solutions for the actuation of implements on heavy-duty mobile machines (HDMMs). A major drawback of this approach is its relatively low energy efficiency due to metering losses—especially for multi-actuator operation and load braking. Several novel, more efficient concepts have already been proposed but involve high component costs for each actuator, which is not acceptable for HDMMs with many actuators that have a medium to low energy turnover. Therefore, this work proposes a novel system design which is based on a conventional LS system—for cheap operation of a high number of low-energy-consuming actuators—but allows to avoid metering losses for single high-energy-consuming actuators by replacing their metering valves with electric-generator-hydraulic-motor (EGHM) units that work similar to pump-controlled concepts. The benefits of the novel concept are explained in detail by looking at the three main throttling functions of an actuator in a typical valve-controlled LS systems, which the novel concept avoids by applying pressure in the actuator return lines and recuperating energy electrically instead of dissipating it by throttling. Furthermore, advantages and challenges for the novel concept are analyzed, and ways to address the latter are presented. Before the novel concept is simulated, the required control algorithms are presented. The simulation study in Amesim and Simulink focuses on a telehandler that utilizes the novel concept for the boom, extension and tilt actuators. Simulation results show that the novel system can decrease the required input energy for typical duty cycles by up to 34% compared to a conventional LS system. At the same time, simulations show that, from an economic perspective, it seems most reasonable to utilize the novel EGHM units only for the boom and extension actuators of the studied telehandler.

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Section: Increased Flowsmentioning

confidence: 99%

Improving the Energy Efficiency of Single Actuators with High Energy Consumption

Fassbender¹,

Minav²,

Brach³

et al. 2021

Linköping Electronic Conference Proceedings

Self Cite

View full text Add to dashboard Cite

show abstract

“…That was when the primary interest was to reduce fuel consumption. Now the focus has shifted towards electrification, see e.g., [13][14][15][16]. This generally means that diesel engines are substituted by battery-powered electric motors.…”

Section: Introductionmentioning

confidence: 99%

Hysteresis Control in Pump-Controlled Systems—A Way to Reduce Mode-Switch Oscillations in Closed and Open Circuits

Kärnell¹,

Ericson²

2022

Energies

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There is growing interest in using electric motors as prime movers in mobile hydraulic systems. This increases the interest in so-called pump-controlled systems, where each actuator has its own drive unit. Such architectures are primarily appealing in applications where energy efficiency is important and electric recuperation is relevant. An issue with pump-controlled systems is, however, mode-switch oscillations which can appear when the pressure levels in the system are close to the switching condition. In this paper, the mode-switching behavior of different generalized closed and open circuit configurations is investigated. The results show that the choice of where to sense the pressures has a huge impact on the behavior. They also show that, if the pressure sensing components are properly placed, closed and open circuits can perform very similarly, but that mode-switch oscillations still can occur in all circuits. Active hysteresis control is suggested as a solution and its effectiveness is analyzed. The outcome from the analysis shows that active hysteresis control can reduce the risk for mode-switch oscillations significantly.

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“…However, almost all hydrostatic pumps have high friction losses, strong wear and often also high volumetric losses at speeds below 500 rpm. While there have been efforts to work around these minimum speed limitations of pumps, they typically depend on introducing new throttling losses via a variable leakage path [5,6].…”

Section: Introductionmentioning

confidence: 99%

Benchmarking the performance of hydrostatic pumps

Mommers¹,

Achten²,

Achten³

et al. 2021

Linköping Electronic Conference Proceedings

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In search for sustainable and clean solutions, the hydraulic industry is forced to develop more efficient alternatives to traditional systems. For mobile applications, battery driven machines are becoming an essential solution. But, electric driven hydraulic systems set completely different demands than classical systems. Since batteries are expensive and bulky, it is no longer acceptable that the majority of the battery stored energy is lost in the hydraulic system. One of the promising solutions for efficiency increase is the application of electrohydraulic actuators (EHAs). Aside from all the inherent control advantages, EHAs deliver energy to each load on demand. This makes them much more efficient than current valve controlled systems, at least in principle. In practice, EHAs require both low and high-speed operation of pumps. Almost all hydrostatic pumps have high friction losses, strong wear and often also high volumetric losses at speeds below 500 rpm. Additionally, it is obvious that the pumps must have the highest efficiency possible. Given these constraints and demands it is understandable that information is needed about the performance of pumps and motors. In the past years, Innas has measured and tested several positive displacement machines and published a comprehensive report about these measurements. This paper will analyse the outcome of the test results, with a special focus on the application in EHAs.

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A closed circuit electro-hydraulic actuator with energy recuperation capability

Cited by 10 publications

References 4 publications

Improving the Energy Efficiency of Single Actuators with High Energy Consumption

Improving the Energy Efficiency of Single Actuators with High Energy Consumption

Hysteresis Control in Pump-Controlled Systems—A Way to Reduce Mode-Switch Oscillations in Closed and Open Circuits

Benchmarking the performance of hydrostatic pumps

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