Dual-Power Electro-Hydrostatic Mode Switching for Smooth Transitions
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Solution Overview
Problem
Current electro-hydrostatic actuators are not cost-effective and energy-efficient for high-power applications, particularly in off-highway vehicles, as they lack efficient power delivery and control accuracy.
Innovation Solution
A blended power system combining hydraulic and electrical power, with a control system that selects operational modes based on load conditions, allowing smooth transitions between modes to minimize jerkiness and optimize power usage, utilizing a bi-directional hydraulic pump, electric motor/generator, and valve arrangement for fluid connections and disconnections to manage power flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If electro-hydrostatic actuators are used for high-power applications, then power delivery capability is improved, but energy efficiency deteriorates
Solution Approach 1:
The system dynamically switches between hydraulic mode and electro-hydrostatic mode based on real-time load conditions. The control system monitors power demands and automatically selects the optimal power source, using hydraulic power for high-power requirements and electrical power for lower-power operations, thereby resolving the contradiction between power delivery capability and energy efficiency
Solution Approach 2:
The system changes operational parameters by transitioning between different operating modes (hydraulic mode, electro-hydrostatic mode, blended mode). This parameter change allows the system to adapt to varying power demands while optimizing energy consumption, effectively resolving the contradiction between delivering high power and maintaining energy efficiency
2Use of energy by moving object
If mode transitions are implemented in the blended power system, then energy efficiency is improved, but system stability deteriorates due to potential jerkiness
Solution Approach 1:
The control system performs preliminary actions by anticipating mode transition requirements and preparing the hydraulic and electrical systems in advance. This includes pre-positioning valves and adjusting flow rates to ensure smooth transitions, thereby preventing jerkiness while maintaining energy efficiency improvements from mode switching
Solution Approach 2:
The system employs feedback mechanisms to monitor transition smoothness and system stability in real-time. The control system adjusts transition parameters based on feedback signals, damping any oscillations or jerky movements that occur during mode transitions, thus resolving the contradiction between energy efficiency and system stability
3Power
If a blended power system is used, then power delivery and control accuracy are improved, but device complexity increases
Solution Approach 1:
The hydraulic pump serves multiple functions by operating in different modes: as a hydraulic pump for high-power delivery, as an electro-hydrostatic actuator for precise control, and as a blended system for optimized performance. This multi-functionality reduces the need for separate dedicated components, thereby managing device complexity while maintaining improved power delivery and control accuracy
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 providing high power density and control accuracy, enabling smooth transitions between modes, thus reducing jerkiness and improving energy efficiency in high-power applications.
Implementation Method 1
an electric motor/generator (108) having a motor shaft (111)
Implementation Method 2
a bi-directional hydraulic pump (102) having a first pump port (104) and a second pump port (106)
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.