Gearbox Pump Displacement Control for Stable Lubrication Pressure
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Solution Overview
Problem
Existing wind turbine gearboxes face issues with insufficient lubrication at low speeds and temperatures due to mechanical pumps operating at fixed displacements, leading to potential oil leakage and increased energy consumption when designed for rated conditions.
Innovation Solution
A control device with a mechanical pump having two-stage displacements and a sensor module to adjust pump operation based on input speed, oil pressure, and optionally rotation speed and temperature, ensuring adequate lubrication while preventing excessive oil flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the displacement of the mechanical pump is designed based on rated load and rated speed, then the pump can provide sufficient oil flow at rated conditions, but at low input speed the rotation speed of the mechanical pump is also low leading to insufficient oil supply
Solution Approach 1:
The mechanical pump is designed with variable displacement capability, allowing the displacement to be adjusted dynamically based on operating conditions. At low speeds, the pump operates at higher displacement to maintain sufficient oil flow, while at rated speeds it operates at lower displacement to avoid excessive flow and high pressure. This dynamic adjustment resolves the contradiction between maintaining adequate lubrication across varying speed conditions.
Solution Approach 2:
The pump displacement parameter is changed based on the input speed condition. The control system adjusts the mechanical pump displacement to be higher when input speed is low and lower when input speed is high, thereby maintaining optimal oil flow and pressure across the entire operating range, preventing both insufficient lubrication and excessive oil flow.
2Reliability
If the displacement of the mechanical pump is designed based on low input rotation speed situation, then sufficient oil supply is provided at low speed, but under rated operating condition an excessive flow occurs causing high oil pressure and increased energy consumption
Solution Approach 1:
The mechanical pump employs variable displacement mechanism that dynamically adjusts pump output based on actual system needs. When operating at rated conditions, the pump reduces displacement to match the lower oil demand, preventing excessive flow and high pressure buildup. This ensures reliable lubrication at all speeds while minimizing energy consumption during high-speed operation.
Solution Approach 2:
The control system monitors operating conditions (speed, pressure, temperature) and provides feedback to adjust the mechanical pump displacement accordingly. This closed-loop control ensures the pump delivers appropriate oil flow and pressure for each operating condition, preventing both insufficient lubrication and excessive energy consumption from over-pumping.
3Reliability
If the displacement of the mechanical pump is designed based on low input rotation speed situation, then sufficient oil supply is provided at low speed, but under rated operating condition excessive flow occurs causing high oil pressure and increased risk of oil leakage
Solution Approach 1:
The pump displacement parameter is dynamically changed based on operating speed. At low speeds, higher displacement ensures sufficient oil supply for reliable lubrication. At rated speeds, displacement is reduced to prevent excessive flow and high pressure, thereby eliminating the root cause of oil leakage risk while maintaining lubrication reliability across all operating conditions.
Data Source
AI summary
A control device for a gearbox which includes a mechanical pump and an electric pump, with the mechanical pump having a first-stage displacement and a second-stage displacement, and the first-stage displacement being less than the second-stage displacement. The control device includes a sensor module for detecting an input speed of a wind wheel, and a rotation speed of the electric pump. The control device also includes a mechanical pump control module for, when the input speed of the wind wheel is greater than or equal to a speed threshold, controlling the mechanical pump to operate at the first-stage displacement, and when the input speed of the wind wheel is less than the speed threshold and the rotation speed of the electric pump is less than a rotation speed threshold, controlling the mechanical pump to operate at the second-stage displacement.