Variable Displacement Hydraulic Pump Control for Motor Overheating
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Solution Overview
Problem
Conventional hydraulic systems in construction machinery face inefficiencies due to fixed displacement pumps, which do not adapt to varying hydraulic power requirements, leading to excess fluid pumping and increased energy consumption, particularly in electrically powered vehicles where power losses and parasitic energy consumption need to be minimized.
Innovation Solution
A hydraulic pump assembly featuring a load-sensing variable displacement pump driven by an electric motor, with a control unit that adjusts the pump's swivel angle and motor speed based on winding temperature to maintain efficient operation, reducing delivery rate when temperature thresholds are exceeded to prevent overheating, while ensuring maximum flow rate whenever possible.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed displacement pump is used, then the device complexity is reduced and cost is lowered, but energy consumption increases due to excess fluid pumping
Solution Approach 1:
The pump transitions from a fixed displacement design to a variable displacement design with adjustable swivel angle, enabling the delivery volume to dynamically adapt to system demands and reduce energy waste
2Use of energy by moving object
If a variable displacement pump is used, then energy efficiency is improved by adapting delivery volume to system demands, but device complexity increases
Solution Approach 1:
The pump's delivery volume is adjusted by changing the swivel angle parameter of the pump vanes, allowing the system to optimize energy efficiency by matching hydraulic output to actual demand conditions
3Use of energy by moving object
If the electric motor operates at high speed to maintain flow rate when pump delivery is reduced, then energy consumption is reduced, but winding temperature increases
Solution Approach 1:
The control unit continuously monitors the winding temperature of the electric motor and adjusts the pump delivery rate accordingly, reducing delivery when temperature thresholds are exceeded to prevent overheating while maintaining efficient operation
4Productivity
If the pump delivers maximum flow rate continuously, then productivity is maintained, but energy consumption increases during low-demand periods
Solution Approach 1:
The pump dynamically adjusts its delivery rate based on real-time system demands, delivering maximum flow when needed for high productivity while reducing flow during low-demand periods to minimize energy consumption
Data Source
AI summary
The present disclosure relates to a hydraulic pump assembly comprising: a variable displacement pump, preferably a load-sensing variable displacement pump, for outputting a volume flow rate of a hydraulic fluid, an electric motor for driving the variable displacement pump, in particular a swashplate or swivel angle pump, via a variable-speed drive shaft, and a control unit which is connected to the variable displacement pump and the electric motor and is configured to provide a predetermined volume flow rate by controlling the variable displacement pump and the electric motor. The hydraulic pump assembly is characterized in that the pump assembly further comprises a temperature sensor connected to the control unit, which senses a winding temperature of the electric motor, wherein as long as the winding temperature is below a threshold, the control unit is configured to provide the predetermined volume flow rate.