Wind Turbine Blade Electro-Thermal Heating Control
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Solution Overview
Problem
Wind turbines in cold climates face icing issues due to ice accumulation on blades, leading to reduced performance and potential damage, and existing Electro-Thermal Heating (ETH) systems face power output fluctuations from supply voltage variations, which can cause overheating and damage.
Innovation Solution
A method to control the ETH system by measuring supply voltage and inserting a variable time-off period in the switching duty cycle, calculated based on the ratio between measured and design voltages, to normalize power output and prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the ETH system is controlled by switching on and off the ETH elements according to a predetermined switching cycle, then the required heat is generated at the required locations in the wind turbine blade, but supply voltage fluctuations can cause the power output to be above design limits and may cause damage to the ETH system and/or to the blade
Solution Approach 1:
The control method measures the actual supply voltage to the ETH system and uses this feedback information to adjust the switching duty cycle. By continuously monitoring voltage fluctuations and modifying the on/off timing accordingly, the system maintains safe operating temperatures while adapting to changing electrical conditions, thus preventing damage without compromising heating effectiveness
Solution Approach 2:
The switching duty cycle is made dynamic rather than fixed. The system adjusts the duration of on and off periods in real-time based on measured supply voltage conditions. When voltage fluctuates, the duty cycle parameters are modified to compensate, ensuring the power output remains within design limits while still providing adequate heating when needed
2Power
If the supply voltage fluctuates, then the power output of the ETH system is affected, but this can increase the heat generated above design limits and cause damage
Solution Approach 1:
The system measures actual supply voltage and uses this feedback to modulate the switching duty cycle. When voltage increases, the system extends off-periods or reduces on-periods to compensate, preventing excessive power output and heat generation. This feedback mechanism ensures safe operating conditions while maintaining heating effectiveness
Solution Approach 2:
The system changes the temporal parameters of the switching duty cycle (on-time and off-time durations) in response to voltage fluctuations. By adjusting these timing parameters dynamically, the system compensates for power variations and prevents excessive heat generation without compromising the heating function when voltage is within acceptable ranges
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 effectively compensates for supply voltage fluctuations, ensuring consistent power output and preventing damage to the ETH system and wind turbine blades by adjusting the duration of the enforced off period within or between switching duty cycles.
Implementation Method 1
Several electro-thermal heating (ETH) elements are attached to, or embedded within, a wind turbine blade to form an ETH system which, when supplied with electrical power, generate heat to increase the surface temperature of the surface of the blade
Data Source
AI summary
The present invention relates to a method of controlling an electro-thermal heating system in a wind turbine blade, comprising measuring a supply voltage to the electro-thermal heating system, determining a duration of a variable time based enforced off period based on the measured supply voltage, and inserting the variable time based enforced off period between subsequent switching duty cycles that controls the electro-thermal heating system. The present invention also relates to a wind turbine that comprises one or more wind turbine blades wherein each wind turbine blade comprises an electro-thermal heating system and a processor adapted to perform the method.