Hydraulic Pump Motor Control for Freewheeling Loss Reduction
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Solution Overview
Problem
Hydraulic systems face issues with freewheeling currents causing thermal losses and reduced efficiency due to constant torque requirements, leading to increased cooling demands and reduced system reliability.
Innovation Solution
Implementing active freewheeling control techniques with intelligent thermal management systems that monitor motor speed and current, using physics-based models to optimize freewheeling methods and fan speed, reducing thermal losses and improving system reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If constant torque requirements are maintained in hydraulic systems, then pump operation is ensured, but thermal losses increase due to freewheeling currents
Solution Approach 1:
The patent applies dynamics by making the freewheeling control adaptive rather than static. The controller dynamically adjusts the freewheeling current based on real-time motor speed feedback, switching between active and passive freewheeling modes depending on operating conditions. This dynamic control optimizes the balance between maintaining pump operation and minimizing thermal losses.
Solution Approach 2:
The patent changes the electrical parameters of the motor control system by implementing variable freewheeling resistance and switching between different freewheeling configurations. The controller modifies the equivalent circuit parameters dynamically, adjusting the freewheeling path resistance based on motor speed to reduce I²R losses while maintaining operational reliability.
2Temperature
If active cooling is continuously applied, then thermal management is maintained, but system efficiency decreases due to additional power consumption
Solution Approach 1:
The patent implements periodic action through intermittent cooling strategies. Instead of continuous cooling, the system periodically activates cooling mechanisms based on thermal accumulation patterns and operational cycles. The controller monitors temperature trends and applies cooling only when necessary, creating a periodic on-off cooling pattern that maintains thermal management while reducing overall power consumption.
Solution Approach 2:
The system applies self-service by utilizing the motor's own operational characteristics to manage its thermal conditions. The freewheeling control strategy leverages the motor's back-EMF and inductive properties to naturally dissipate heat during deceleration and idle periods. The system serves its own cooling needs through intelligent electrical control rather than requiring continuous external cooling power.
3Loss of energy
If freewheeling control is optimized, then power losses are reduced, but system complexity increases due to additional control mechanisms
Solution Approach 1:
The patent achieves universality by designing a multi-functional controller that handles multiple tasks: motor speed control, freewheeling management, thermal monitoring, and cooling activation. This single controller performs what would otherwise require separate dedicated circuits, reducing overall system complexity while maintaining optimized freewheeling control to minimize power losses.
Solution Approach 2:
The patent implements feedback mechanisms where the controller continuously monitors motor speed, current, and temperature to dynamically adjust freewheeling resistance and cooling activation. This closed-loop feedback enables the system to automatically optimize power loss reduction without requiring complex manual tuning or multiple independent control systems, simplifying the overall control architecture.
Data Source
AI summary
A hydraulic system includes a hydraulic pump and a motor configured to drive the hydraulic pump. A sensor measures motor speed. A controller includes a model configured to determine system parameters based on the measured motor speed, and the controller is configured to output control signals to the motor and a fan based on the determined system parameters.