Hydraulic Energy Regeneration Control for Work Machine Pumps
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Solution Overview
Problem
The existing hydraulic fluid energy regeneration devices for work machines face issues with increased drag loss and decreased regeneration efficiency due to excessive or insufficient revolution speed of the electric motor relative to the regeneration power and pump power.
Innovation Solution
A work machine configuration that includes multiple hydraulic actuators, pumps, and sensors, with a controller that computes and adjusts the regeneration flow rate, pump power, and target assist flow rate to select the required revolution speed of the regeneration hydraulic motor and hydraulic pump, ensuring optimal operation and preventing drag loss and efficiency decline.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the revolution speed of the electric motor is controlled according to a target flow rate or constant revolution speed command, then the electric motor can operate at a predetermined speed, but the drag loss of the regeneration hydraulic pump and hydraulic pump increases when the speed is excessive relative to the regeneration power or pump power
Solution Approach 1:
The patent applies dynamics by transitioning from a static constant revolution speed command to a dynamic speed control system. The controller continuously adjusts the electric motor's revolution speed based on real-time feedback from operation amount sensors and pressure sensors, ensuring the motor operates at the optimal speed that matches the current regeneration power and pump power requirements, thereby preventing excessive drag loss.
Solution Approach 2:
The patent implements feedback control by using operation amount sensors to detect the operator's input and pressure sensors to monitor the actual pressure in the hydraulic system. The controller receives these feedback signals and adjusts the electric motor's revolution speed accordingly, creating a closed-loop control system that prevents the motor from operating at excessive speeds relative to the available power, thus reducing drag loss.
2Speed
If the revolution speed of the electric motor is controlled according to a target flow rate or constant revolution speed command, then the electric motor can operate at a predetermined speed, but the regeneration efficiency of the regeneration hydraulic motor decreases when the speed is insufficient relative to the regeneration power or pump power
Solution Approach 1:
The patent applies dynamics by transitioning from a static constant revolution speed command to a dynamic speed control system. The controller continuously adjusts the electric motor's revolution speed based on real-time feedback from operation amount sensors and pressure sensors, ensuring the motor operates at the optimal speed that matches the current regeneration power and pump power requirements, thereby preventing excessive drag loss.
Solution Approach 2:
The patent implements feedback control by using operation amount sensors to detect the operator's input and pressure sensors to monitor the actual pressure in the hydraulic system. The controller receives these feedback signals and adjusts the electric motor's revolution speed accordingly, creating a closed-loop control system that prevents the motor from operating at excessive speeds relative to the available power, thus reducing drag loss.
3Power
If the electric motor operates at high revolution speed to meet high flow rate demands, then the pump can deliver sufficient hydraulic fluid, but energy is wasted when the regeneration power is insufficient to drive the pump at the required speed
Solution Approach 1:
The patent implements feedback control by using operation amount sensors to detect the operator's input and pressure sensors to monitor the actual pressure in the hydraulic system. The controller receives these feedback signals and adjusts the electric motor's revolution speed accordingly, creating a closed-loop control system that prevents the motor from operating at excessive speeds relative to the available power, thus reducing drag loss.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the revolution speed parameter of the electric motor based on the balance between regeneration power and pump power requirements. Instead of maintaining a constant high speed, the system varies the speed parameter to match the available regeneration power, thereby reducing energy conversion losses while still meeting the hydraulic power demands when regeneration power is sufficient.
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
This configuration effectively prevents drag loss and maintains regeneration efficiency by optimizing the revolution speed of the electric motor, ensuring efficient energy regeneration and use in work machines.
Implementation Method 1
a regeneration hydraulic motor 13 that is driven by a return hydraulic fluid discharged from a first hydraulic actuator 3a
Implementation Method 2
a first hydraulic pump 15 mechanically coupled to the regeneration hydraulic motor 13
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Provided is a work machine capable of regenerating a return hydraulic fluid from a hydraulic actuator while preventing a drag loss of a regeneration hydraulic motor and a hydraulic pump from increasing and preventing the regeneration efficiency of the regeneration hydraulic motor from decreasing. A controller 100 computes a required regeneration hydraulic motor revolution speed from a displacement of a regeneration hydraulic motor 13 and a regeneration flow rate of the regeneration hydraulic motor, computes a required first hydraulic pump revolution speed from a displacement of a first hydraulic pump 15 and a target assist flow rate of the first hydraulic pump, and selects a greater one of the required regeneration hydraulic motor revolution speed and the required first hydraulic pump revolution speed as a target revolution speed of an electric motor 14.