Wind Turbine Internal Power Supply Switching for Overvoltage Response
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Solution Overview
Problem
Existing wind turbine internal demand control systems face challenges in rapidly responding to dynamic voltage changes, particularly overvoltages, due to the use of variable transformers with long response times and the inefficiencies of autotransformers, which require significant installation and operational effort, and active switching elements like IGBTs that are not robust enough for quick switching off.
Innovation Solution
A switching device with a double configuration, featuring an active switching element and a passive inductance as a switching-off element, where the passive component is connected in parallel to the transformer during overvoltage faults, allowing for quick voltage reduction and minimizing power losses during normal operation, using a choke as the inductance to replace the need for active switching-off elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a variable transformer is used to supply the internal demand network, then voltage fluctuations in the supply network can be compensated, but the response time is very long and cannot respond rapidly to dynamic voltage changes
Solution Approach 1:
The patent divides the transformer into two separate components: a fixed transformer for voltage transformation and a switching device with inductance for rapid response. This segmentation allows each component to specialize - the transformer handles steady-state voltage compensation while the switching device handles dynamic overvoltage protection with millisecond response time.
Solution Approach 2:
The patent introduces a dynamic switching mechanism that can rapidly change the circuit configuration in response to overvoltage conditions. The switching device with active and passive switching elements provides dynamic protection by quickly connecting or disconnecting the inductance based on real-time voltage monitoring, enabling response times in the millisecond range.
2Adaptability or versatility
If an autotransformer with inverter is used to provide high voltage variability, then voltage can be adjusted in a wide range, but the installation effort and operational complexity are significantly increased
Solution Approach 1:
The patent extracts the voltage variability function from a complex autotransformer-inverter system and implements it through a simpler switching device configuration. By using a fixed transformer combined with a switching device that can connect or disconnect inductance, the system achieves adequate voltage adaptation without the complexity of variable transformers or inverters.
Solution Approach 2:
The patent replaces expensive, complex autotransformers with inverters with a simpler, more robust switching device configuration. The switching device with active and passive switching elements provides a cost-effective solution that achieves the necessary voltage adaptation while significantly reducing installation and operational complexity.
3Speed
If IGBTs are used as active switching elements for quick switching, then switching speed is sufficient, but they are not robust enough for reliable switching off in overvoltage conditions
Solution Approach 1:
The patent introduces a passive switching element (inductance) as an intermediary to assist the active switching element during the switching-off process. The inductance acts as a buffer that facilitates current commutation, allowing the active switching element to turn off reliably even under overvoltage conditions by providing a controlled path for current decay.
Solution Approach 2:
The patent creates a composite switching mechanism combining active and passive switching elements. This hybrid approach leverages the fast switching capability of active elements (like IGBTs) and the robustness of passive elements (inductance) to achieve both quick response and reliable operation under extreme conditions.
4Ease of operation
If the entire power flows through the main inductance of the autotransformer during normal operation, then voltage control is achieved, but power losses are significantly increased
Solution Approach 1:
The patent applies partial action by using the inductance only when needed for voltage control or overvoltage protection, rather than having all power flow through it continuously. The switching device connects or disconnects the inductance based on system conditions, minimizing power losses during normal operation while maintaining voltage control capability when required.
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 configuration enables rapid and robust switching, ensuring effective protection against overvoltage with reduced voltage supply, minimizing power losses, and simplifying the design while reducing the number of switching elements needed, thus achieving high robustness and quick switching dynamics.
Implementation Method 1
A switching device with a double configuration, featuring an active switching element and a passive inductance as a switching-off element
Implementation Method 2
with a transformer being provided for supplying the internal demand network
Data Source
Figure 1~2
Figure 3~5
Figure 6a~7
AI summary
The invention relates to a wind energy plant with a wind rotor (10), a generator (12) driven by it for generating electrical power and a connecting line (17) for delivering the electrical power to a grid (9), further comprising a personal demand grid (3) for supply electrically operated components (8) of the wind turbine and a personal requirement control (4) for controlling the voltage in the personal requirement network (3). In order to improve the personal requirement control (4) and its supply for wind turbines of the type mentioned at the outset, the invention provides that the personal requirement control (4) has a switching device (5) which is designed to switch between a normal supply from the connecting line (17) and a Accident supply, in which the voltage is reduced compared to the normal supply, the switching device (5) has a switching element (52) and a switching element (51), and only the switching element (52) is an active switching element and that switch-off element (51) is designed as a passive component, in particular an inductance.