Electric Hydraulic Pump Speed Control for Power-Limited Work Machines
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electrically driven hydraulic work machines, such as hydraulic excavators, can suddenly stop due to abnormal battery voltage drops or excessive power consumption, leading to instability and safety risks, especially when operating heavy work implements.
Innovation Solution
An electrically driven hydraulic work machine with a controller that adjusts the electric motor's revolution speed based on target power consumption, using a maximum allowable power setting device and pressure sensors to ensure power consumption remains within safe limits, preventing sudden stops and voltage drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the electric motor drives the hydraulic pump at high power to operate heavy work implements, then the work capability is improved, but the power consumption exceeds the maximum allowable power causing sudden stops
Solution Approach 1:
The controller continuously monitors the actual power consumption of the electric motor and compares it with the maximum allowable power. When the actual power consumption approaches or exceeds the maximum allowable power, the controller automatically adjusts the revolution speed of the electric motor to reduce power consumption, thereby preventing sudden stops while maintaining optimal work capability.
Solution Approach 2:
The system dynamically adjusts the revolution speed of the electric motor based on real-time power consumption conditions. The controller modifies the motor speed to ensure that power consumption remains within the maximum allowable limit, allowing the system to adapt to varying load conditions and prevent excessive power consumption that would cause sudden stops.
2Productivity
If the electric motor consumes high power to maintain operation speed, then the work efficiency is improved, but the battery voltage drops below the allowable range causing sudden stops
Solution Approach 1:
The controller monitors the power consumption and its effect on battery voltage in real-time. When high power consumption causes voltage to drop below the allowable range, the controller adjusts the electric motor's revolution speed to reduce power consumption, thereby stabilizing the voltage and preventing sudden stops while minimizing impact on work efficiency.
3Power
If the commercial power supply provides high current to the electric motor, then the power capacity is improved, but the current exceeds the breaker capacity causing interrupt operation
Solution Approach 1:
The controller monitors the current drawn from the commercial power supply and compares it with the breaker's current capacity. When the current approaches or exceeds the breaker capacity, the controller reduces the electric motor's revolution speed to limit current consumption, preventing breaker tripping and ensuring continuous operation while maintaining adequate power delivery.
Data Source
AI summary
In a hydraulic drive system used for an electrically driven hydraulic work machine that drives a hydraulic pump by an electric motor and supplies a hydraulic fluid to plural actuators to carry out work, the power consumption of the hydraulic pump is kept from exceeding a value decided in advance. For this purpose, a controller calculates target power to be consumed by the hydraulic pump on the basis of the capacity of the hydraulic pump, the delivery pressure of the hydraulic pump sensed by a pressure sensor, and a target revolution speed of the electric motor, and limits the target revolution speed of the electric motor in such a manner that the target power falls within a range of the maximum allowable power.