Wind Turbine Pitch Battery Testing via Rotor Position Segmentation
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Solution Overview
Problem
Modern wind turbines with curved rotor blades face challenges in testing the capacity of pitch system batteries, as the center of gravity shift introduces a strong dependency between blade position and motor torque, leading to inaccurate battery testing, where batteries may appear functional even if non-operative.
Innovation Solution
A method and system that define a rotor position range requiring energy equal to or above a gravity threshold to test the capacity of pitch system batteries, involving monitoring rotor positions, initiating a test procedure, pitching blades via the power grid and energy storage devices, measuring operating conditions, and determining battery capacity based on these conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If rotor blades are tested by driving them to feathered position using energy storage devices, then battery capacity can be evaluated, but curved rotor blades may be purely driven by gravity in certain rotor positions with no energy being required from the batteries, leading to false positive test results
Solution Approach 1:
The patent changes the test parameters by selecting specific rotor position ranges where gravity forces are minimized or controlled. Instead of testing at any rotor position, the system identifies and tests within position ranges where the gravitational torque on the blade is least, ensuring that battery energy consumption is the dominant factor. This parameter change (selecting specific position ranges) resolves the contradiction by making the test reliable even for curved blades where gravity might otherwise dominate.
Solution Approach 2:
The patent applies preliminary action by pre-determining the rotor position ranges where gravity forces are minimal before conducting the actual battery test. The system first identifies these optimal position ranges, then positions the blade within this range before initiating the battery-driven pitch test. This preliminary positioning ensures that when the test is executed, the batteries are the primary energy source, eliminating false positives from gravity-driven movement.
2Ease of operation
If a single test procedure is used for all rotor positions, then testing is simple, but it cannot account for gravity's varying influence on curved blades at different positions
Solution Approach 1:
The patent segments the rotor position into different ranges based on gravity influence. Instead of using a single test procedure for all positions, the system divides the 360-degree rotor position into multiple segments or ranges, where each range is characterized by specific gravitational conditions. The test procedure is then selected or adjusted based on which segment the current rotor position falls into. This segmentation maintains operational simplicity through automated selection while ensuring measurement precision by matching the test conditions to the physical realities at each position range.
3Device complexity
If rotor position is not considered in battery testing, then the test procedure is straightforward, but batteries may appear functional even if non-operative due to gravity-driven blade movement
Solution Approach 1:
The patent implements feedback by continuously monitoring the actual rotor position during the battery test and comparing it against the predetermined optimal position ranges. The system provides feedback on whether the blade is within the correct test range and adjusts or repositions it as needed. This feedback mechanism ensures that the test is always conducted under conditions where gravity influence is controlled, making the battery functional assessment reliable while keeping the procedure complexity manageable through automated control.
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
Ensures reliable battery testing by accounting for rotor position and gravity forces, preventing false positives and ensuring that batteries can effectively drive rotor blades to a feathered position during grid loss scenarios.
Implementation Method 1
the pitch drive motor is coupled to the pitch drive gearbox so that the pitch drive motor imparts mechanical force to the pitch drive gearbox
Implementation Method 2
curved rotor blades may be purely driven by gravity in certain rotor positions with no energy being required from the batteries to reach the feathered position
Data Source
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AI summary
A method for testing capacity of at least one energy storage device of a pitch drive mechanism to drive a first rotor blade 22 of a wind turbine 10 connected to a power grid includes defining a rotor position range for implementing a first test procedure for the energy storage device(s). Further, the method includes monitoring a rotor position of the first rotor blade 22. When the rotor position of the first rotor blade 22 enters the rotor position range, the method includes initiating the first test procedure. The first test procedure includes pitching the first rotor blade 22 via the energy storage device(s), measuring at least one operating condition of the energy storage device(s) during pitching, and determining a capacity of the energy storage device(s) to drive the first rotor blade 22 based on the operating condition(s) thereof.