Hydraulic Pump Torque Control for Single-Motor Load Protection
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Solution Overview
Problem
Efficient use of electric motors in work machines to drive accessory systems without overloading is a challenge, particularly when the combined torque requirements exceed the motor's capacity.
Innovation Solution
Implementing a controller to estimate the total torque of the motor and adjust the operating torque of hydraulic pumps to prevent overloading by modulating the displacement and pressure of variable displacement pumps and actuating valves in response to threshold torque limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a single electric motor drives multiple hydraulic pumps to power various accessory systems, then the vehicle can utilize electric motor power efficiently, but the motor may become overloaded when combined torque requirements exceed motor capacity
Solution Approach 1:
The controller continuously monitors the torque requirements of multiple hydraulic circuits and adjusts pump operations in real-time based on feedback from torque sensors and system pressure sensors, preventing motor overload by dynamically balancing the load across available power capacity
Solution Approach 2:
The system dynamically adjusts the operation of variable displacement pumps based on changing torque requirements, allowing the motor to operate within safe torque limits while still meeting the hydraulic demands of various accessory systems at different operating conditions
2Loss of energy
If variable displacement pumps are used to adjust hydraulic flow and pressure, then energy efficiency can be improved, but the system complexity increases
Solution Approach 1:
The controller serves multiple functions simultaneously: it manages variable displacement pump operations for energy efficiency, monitors torque across multiple hydraulic circuits, and coordinates between different pumps to prevent motor overload, consolidating control logic into a single intelligent component that handles diverse control tasks
Data Source
AI summary
A work machine includes a first hydraulic circuit, a second hydraulic circuit, a single electric motor, and a controller. The first hydraulic circuit includes a first pump and a first valve. The first pump is configured to drive a first group of hydraulic accessories. The second hydraulic circuit includes a second pump and a variable pressure valve. The second pump is configured to drive a second group of hydraulic accessories. The single electric motor is connected/configured to drive the first pump and the second pump. The controller configured to estimate a torque of the second pump, estimate a total torque of the motor as a sum of a current operating torque of the motor and the estimate of the torque of the second pump, and, on condition the total torque of the motor is greater than a threshold torque, lower an operating torque of at least one of the first pump or the second pump.