Wind Turbine Heating Circuit Using PWM for Stable Temperature Control
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Solution Overview
Problem
Wind turbines operating in remote and extreme weather locations face challenges in maintaining consistent power levels for ice mitigation systems due to limitations in power devices, leading to potential temperature cycling and electromagnetic compatibility issues.
Innovation Solution
A heating system with a heating circuit that receives a voltage signal from the electrical grid, processes it using pulse width modulation (PWM) and integral cycle control (ICC) to provide continuous temperature control to heating elements, minimizing temperature cycling and reducing harmonics and electromagnetic emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional heating systems are used in wind turbines, then heating function is provided, but temperature cycling occurs and electromagnetic compatibility issues arise
Solution Approach 1:
The patent applies periodic action by using pulse width modulation (PWM) to switch the heating element on and off in controlled cycles. The controller adjusts the duty cycle of the PWM signal to maintain the heating element temperature within a specified range, preventing excessive temperature cycling while providing continuous heating function. This periodic switching resolves the contradiction by eliminating harmful temperature excursions while maintaining reliable heating operation.
Solution Approach 2:
The patent changes the electrical parameters by using integral cycle control (ICC) to adjust the firing angle of the triac and modify the RMS voltage supplied to the heating element. By dynamically adjusting these electrical parameters based on temperature feedback, the system maintains stable heating performance while minimizing electromagnetic emissions and preventing harmful temperature cycling. This parameter adjustment resolves the contradiction between reliable heating and electromagnetic compatibility.
2Ease of operation
If PWM signal is superimposed on voltage signal for temperature control, then continuous temperature control is achieved, but system complexity increases
Solution Approach 1:
The patent merges multiple control functions into a single integrated heating circuit. The circuit combines PWM signal generation, ICC-based phase angle control, temperature sensing, and feedback control into one unified system. By merging these functions, the patent achieves precise continuous temperature control while minimizing the increase in system complexity through functional integration rather than adding separate independent control systems.
Solution Approach 2:
The heating circuit incorporates self-regulating features where the controller automatically adjusts the PWM duty cycle and ICC firing angle based on temperature feedback from the heating element. This self-service capability eliminates the need for external complex control systems, achieving precise temperature control while keeping the overall system complexity manageable through autonomous operation.
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
The system ensures reliable operation by maintaining heating element temperatures within a range, reducing harmonics effects on the grid, improving electromagnetic compatibility, and eliminating electromagnetic emissions.
Implementation Method 1
providing continuous temperature control to at least one heating element of the heating system via the PWM signal
Implementation Method 2
maintaining a temperature of the at least one heating element within a temperature range using the PWM signal to minimize temperature cycling
Data Source
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AI summary
A method of operating a heating system of a wind turbine connected to an electrical grid. The method includes receiving, via a heating circuit of the heating system, a voltage signal from the electrical grid. The method also includes processing the voltage signal using the heating circuit of the heating system. Processing the voltage signal using the heating circuit of the heating system includes superimposing a pulse width modulation (PWM) signal onto the voltage signal. Further, the method includes providing continuous temperature control to at least one heating element of the heating system via the PWM signal from the heating circuit. In addition, the method includes maintaining a temperature of the at least one heating element within a temperature range using the PWM signal during operation of the wind turbine to minimize temperature cycling of the at least one heating element.