Dual-Power Electro-Hydrostatic Control for Smooth Mode Transitions
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Solution Overview
Problem
Current state-of-the-art technologies have not provided a cost-effective and energy-efficient solution for high-power applications of electro-hydrostatic actuators, particularly in off-highway vehicles, which require efficient power delivery and control.
Innovation Solution
A blended power system combining electrical and hydraulic power, utilizing a bi-directional hydraulic pump, electric motor/generator, and a valve arrangement to manage fluid flow paths and actuator connections, allowing smooth transitions between operational modes and minimizing jerkiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a hydraulic system uses self-contained electro-hydrostatic actuators for high-power applications, then power delivery capability is improved, but energy efficiency and cost-effectiveness deteriorate
Solution Approach 1:
The system dynamically switches between hydraulic power source and electrical power source based on real-time power demands and operating conditions. The control system monitors load requirements and transitions between power sources to optimize energy efficiency while maintaining high power delivery capability when needed.
Solution Approach 2:
The hybrid power system integrates multiple power sources (hydraulic and electrical) into a single unified system that can deliver power through either source or both simultaneously. This multi-functional architecture allows the system to adapt to varying power requirements and improve overall energy efficiency compared to dedicated high-power hydraulic actuators.
2Adaptability or versatility
If the hydraulic system switches between different operational modes, then adaptability to different load conditions is improved, but system complexity increases
Solution Approach 1:
The valve arrangement is divided into multiple independent valves (first valve, second valve, third valve) that can be controlled separately to manage different hydraulic flow paths. This segmentation allows flexible mode transitions by independently controlling each valve's position, enabling adaptability to different load conditions while maintaining manageable system complexity through modular valve control.
3Adaptability or versatility
If the system transitions between hydraulic and electro-hydrostatic modes, then power delivery flexibility is improved, but mechanical jerkiness may increase
Solution Approach 1:
The control system prepares for mode transitions by pre-positioning valves and pre-charging hydraulic circuits before actual power source switching occurs. This preliminary action ensures that hydraulic pressure and flow paths are ready before the transition, preventing sudden pressure changes and minimizing mechanical jerkiness during mode switches.
Solution Approach 2:
The valve arrangement acts as an intermediary mechanism that smoothly mediates transitions between hydraulic and electro-hydrostatic power sources. By controlling valve positions and hydraulic flow paths, the system can gradually transfer power delivery from one source to another, reducing abrupt changes and minimizing mechanical jerkiness during mode transitions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The blended power system enhances operating efficiency by leveraging high power density of hydraulic power and control accuracy of electrical power, enabling seamless mode transitions and reducing mechanical jerkiness in high-power applications.
Implementation Method 1
a bi-directional hydraulic pump (102) having a first pump port (104) and a second pump port (106)... a first hydraulic flow path (116) for fluidly connecting the hydraulic pressure source (114) to the first pump port (104)... a third hydraulic flow path (124) for fluidly connecting the first pump port (104) to the first actuator port (120)
Implementation Method 2
an electric motor/generator (108) mechanically coupled to the bi-directional hydraulic pump (102)
Implementation Method 3
A first valve (132) may be positioned along the first hydraulic flow path (116)... A second valve (134) may be positioned along the second hydraulic flow path (118)... A third valve (136) may be positioned along the third hydraulic flow path (124)
Data Source
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AI summary
The present disclosure relates to a blended or hybrid power system with increased operating efficiency. The blended power system combines the advantages of electrical power with the advantages of hydraulic power when delivering power to a hydraulic actuator. The hydraulic power provides higher power density and the electrical power provides high efficiency and control accuracy in the blended power system. In a blended power system, a control system may be configured to select different modes of operation based on the loads encountered in the combined hydraulic and electrohydrostatic system. The blended power system also allows for smooth and uninterrupted transitions between the different modes of operation within the blended power system. Thus, jerkiness in the blended power system may be minimized or eliminated.