Wind Turbine Bearing Preload Control via Thermal Expansion
Solution Overview
Problem
The preload of wind turbine bearings varies significantly due to temperature changes and operating conditions, leading to stress, wear, and reduced efficiency and lifespan of the bearings, especially in direct-drive wind turbines.
Innovation Solution
A control method and system that estimates and adjusts the preload of wind turbine bearings by monitoring the temperature of the outer and inner rings, maintaining the preload within a predetermined range through heating or cooling, thereby optimizing the bearing's working life and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the bearing is assembled with a relatively small amount of interference (preload), then the initial air gap is small and the electric machine efficiency is high, but the preload varies significantly over time due to temperature changes and operating conditions, leading to stress, wear, and reduced bearing lifespan
Solution Approach 1:
The patent implements a feedback control system that continuously monitors the actual preload of the bearing using sensors (such as strain gauges or pressure sensors) and compares it with a reference preload value. Based on the deviation detected, the system automatically adjusts the preload by controlling the thermal expansion of the bearing housing or support structure, thereby maintaining optimal preload conditions throughout operation and preventing both excessive wear and air gap variations
Solution Approach 2:
The patent utilizes thermal expansion parameter changes by heating or cooling the bearing support structure or housing to dynamically adjust the bearing preload. By changing the temperature of the support structure, the dimensional parameters of the housing change, which in turn adjusts the preload on the bearing and the air gap in the electric machine, allowing optimization of both efficiency and reliability under varying operating conditions
2Reliability
If the bearing preload is increased to ensure long working life and reduce wear, then the bearing can withstand higher stresses, but the air gap size increases and the efficiency of the electric machine decreases
Solution Approach 1:
The patent transforms the static preload setting into a dynamic adjustment system where the bearing preload is continuously adapted based on real-time operating conditions such as temperature, load, and speed. This dynamic control allows the system to maintain the bearing preload within an optimal range that ensures both sufficient load capacity for long bearing life and appropriate air gap for high electric machine efficiency, rather than relying on a fixed initial preload setting
3Adaptability or versatility
If the preload is set to accommodate a wide temperature range at installation, then the bearing can operate in various environmental conditions, but the preload varies significantly during operation due to heat generated by the rotary electric machine and friction in the bearing
Solution Approach 1:
The feedback control system continuously monitors the actual preload during operation and compares it with the desired reference value. When temperature changes cause preload deviation, the system detects this through sensors and automatically compensates by adjusting the thermal state of the support structure, thereby maintaining stable preload despite variations in operating temperature and ensuring consistent bearing performance across different environmental conditions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures a stable preload, extending the bearing's lifespan and improving the efficiency of the electric machine by maintaining a consistent air gap, thus addressing the issues of stress and wear caused by preload variations.
Implementation Method 1
detecting the temperature of the outer ring; detecting the temperature of the inner ring
Implementation Method 2
correcting the preload on the bearing comprises directly or indirectly heating or cooling the outer ring and/or inner ring
Implementation Method 3
correcting the preload on the bearing comprises directly or indirectly heating or cooling the outer ring and/or inner ring
Implementation Method 4
controlling the temperature of the outer ring and the inner ring as a function of the temperature difference between the outer ring and the inner ring so as to keep the preload within the predetermined acceptance range
Data Source
AI summary
A control method configured to control the preload of a bearing includes estimating the preload on the bearing; comparing the estimated preload with a predetermined acceptance range; and correcting the preload on the bearing when the preload is outside the acceptance range.