Fluid Counterweight for Balanced Wind Turbine Hub Installation
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Solution Overview
Problem
The installation of wind turbine blades, especially in offshore direct drive turbines, is hindered by the need for high torque to rotate an unbalanced rotor hub, which can exceed the capacity of the gearbox, leading to increased costs and complexity, particularly due to limited wind windows and the requirement for large crane operations.
Innovation Solution
A counterweight system that uses a support structure with a counterweight mass, which can be rotated about a pitch axis and filled with fluid to adjust its weight and torque, allowing for balanced rotation of the hub during blade installation without relying on an unbalanced rotor turning gear, thereby reducing strain on the drive train.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If individual blades are mounted horizontally or vertically, then installation time is reduced and higher wind speeds are tolerated, but very high torque is required to rotate the unbalanced hub
Solution Approach 1:
The patent applies a counterweight system mounted on the hub that can be adjusted to compensate for the unbalanced weight during blade installation. The counterweight is positioned to offset the gravitational torque caused by the unbalanced blade configuration, enabling the hub to be rotated with significantly reduced torque requirements. This allows individual blades to be installed in horizontal or vertical positions without overloading the drive train.
2Ease of manufacture
If a complete rotor assembly is hoisted and mounted, then installation is simplified, but a large surface area is required which is typically not available in offshore wind turbines
Solution Approach 1:
The patent divides the rotor assembly into separate components (hub and individual blades) that can be installed sequentially. The hub is first mounted to the nacelle, then blades are attached one at a time using the counterweight system. This segmentation eliminates the need for large surface areas required for complete rotor assembly handling, making the process suitable for offshore installations with limited workspace.
3Reliability
If the gearbox is designed to withstand the extreme loads from unbalanced rotor rotation, then the system can handle individual blade installation, but cost and weight of the wind turbine increase
Solution Approach 1:
The counterweight system prevents extreme loads from being imposed on the gearbox during blade installation. By balancing the hub dynamically, the counterweight reduces the torque requirements to levels that the normally-rated gearbox can handle without modification. This avoids the need to oversize the gearbox, thereby preventing increased cost and weight.
4Ease of operation
If blades are installed in the 'bunny ears' configuration with two blades pointing upwards, then no rotation of the rotor is needed for mounting the third blade, but the prevailing wind speed must be below a predetermined value for a prolonged period time
Solution Approach 1:
The patent employs a dynamic counterweight system that can be adjusted during the installation process. This allows the installation team to install blades in horizontal or vertical positions regardless of wind speed conditions. The counterweight compensates for the unbalanced configuration, enabling safe rotation and installation even in higher wind speeds, thus increasing adaptability to varying weather 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 method enables efficient and balanced rotation of the wind turbine rotor during blade installation, reducing the load on the gearbox and allowing for installation in higher wind conditions, thus minimizing costs and operational challenges.
Implementation Method 1
A counterweight system that uses a support structure with a counterweight mass, which can be rotated about a pitch axis and filled with fluid to adjust its weight and torque
Implementation Method 2
A counterweight system for mounting a rotor blade on a balanced rotatable hub... The at least one counterweight mass can be coupled to the distal end of the at least one support structure
Data Source
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AI summary
A counterweight system for mounting a rotor blade on a balanced rotatable hub of a wind turbine is disclosed. The rotatable hub can have at least one blade root region configured to receive a blade root of the rotor blade, and also have a pitch system configured to rotate the rotor blade around a pitch axis. The counterweight system can have at least one support structure having a proximal end spaced apart from a distal end with the proximal end mountable to at least one blade root region of the rotatable hub. The at least one counterweight mass can be at least partially filled with fluid and coupled to the distal end of the at least one support structure. The at least one support structure can be arranged substantially parallel to the pitch axis such that the pitch system rotates the counterweight mass about the pitch axis.