Wind Turbine Ring Gear Drive Control for Balanced Load Sharing
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Solution Overview
Problem
In wind turbines, the variation in backlash between drive devices and the ring gear leads to uneven load distribution, causing excessive stress on some devices and reducing their lifespan, especially during pitch and yaw control operations, particularly under extreme wind conditions.
Innovation Solution
A wind turbine drive system with multiple drive devices, each equipped with a motor drive portion, speed reducing portion, and motor braking portion, along with a state quantity detection unit and control unit that adjusts the load by measuring forces and controlling the motor drive and braking portions to equalize the load across all devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple drive devices are used to drive the ring gear, then the drive force is sufficient for pitch and yaw control, but the load is unevenly distributed among the drive devices due to backlash variation
Solution Approach 1:
The control unit receives load information from each drive device and adjusts the drive force of each device based on feedback about the actual load being applied. This closed-loop control ensures that all drive devices share the load evenly despite variations in backlash, resolving the contradiction between having sufficient total drive force and maintaining uniform load distribution across multiple devices
Solution Approach 2:
The system dynamically adjusts the drive force of each drive device based on real-time load conditions rather than applying static equal force to all devices. This dynamic control allows the system to adapt to varying backlash conditions and maintain optimal load distribution throughout operation
2Reliability
If a releasing unit is provided in each drive device, then the system can release drive force transmission, but the load variation among drive devices still causes reduced device life
Solution Approach 1:
The control unit proactively balances the load among drive devices before excessive load accumulation occurs. By continuously monitoring and adjusting drive forces, the system prevents any single device from bearing disproportionately high loads that would accelerate wear and reduce device life, even when releasing units are present
3Power
If the number of drive devices is increased to handle higher wind turbine output, then the power capacity is sufficient, but the load variation problem becomes more pronounced
Solution Approach 1:
The feedback control mechanism scales effectively to any number of drive devices. The control unit independently manages the drive force of each device based on its specific load conditions, allowing the system to maintain uniform load distribution regardless of whether there are three, six, or more drive devices working together to provide the required power capacity
Data Source
AI summary
A wind turbine drive system includes a plurality of drive devices, a state quantity detection unit, and a control unit. The plurality of drive devices are provided in a first structure (a nacelle), and a ring gear is provided in a second structure (a tower). Each of the drive devices includes a motor drive portion, a speed reducing portion, and a motor braking portion for braking the motor drive portion. The state quantity detection unit detects a load between a meshing portion of each of the drive devices and the ring gear. Based on the thus detected load for the each of the drive devices, the control unit controls at least one of the motor drive portion and the motor braking portion so as to reduce a degree of variation in the load among the drive devices.