Wind Turbine Voltage Expander for Extended Range
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Solution Overview
Problem
Wind energy installations, particularly offshore farms, face challenges with voltage deviations due to insufficient infrastructure, leading to the need for increased dielectric strength and voltage range, which existing solutions like step transformers and semiconductor elements are unable to address effectively, especially in modern, high-power turbines.
Innovation Solution
A voltage expander system using a small transformer with a switching mechanism, looped into the connection line between the wind turbine and the grid, allows for multi-stage voltage adjustments with significantly reduced power requirements, enabling faster and more efficient voltage range expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a step transformer with tap changer is used to increase voltage range, then the voltage range can be covered, but the switching times are relatively long (up to a few minutes) and the tap changers are subject to wear
Solution Approach 1:
The patent replaces the mechanical tap changer system with a semiconductor-based switching mechanism. The voltage range is adjusted by switching between different transformer winding connections (star/delta configurations) using semiconductor switches, eliminating the need for mechanical movement and contact wear while achieving instantaneous switching.
Solution Approach 2:
The patent changes the electrical parameters (connection configuration) of the transformer windings rather than physically moving taps. By switching between star and delta connections and adjusting the phase displacement, the voltage range is modified without mechanical intervention, reducing switching time and wear.
2Loss of time
If semiconductor elements are used to avoid wear and reduce switching time, then switching performance improves, but the semiconductor elements have to be dimensioned extremely large and are therefore expensive
Solution Approach 1:
Instead of using semiconductor switches to handle the full transformer power, the patent uses them only for switching between predefined voltage configurations. The semiconductor elements control the connection state rather than carrying the full load current continuously, allowing for smaller, more cost-effective components.
Solution Approach 2:
The transformer is divided into multiple windings with different connection configurations. The semiconductor switches segment the power flow paths, directing current through different winding combinations to achieve various voltage outputs without requiring a single large switch to handle all configurations.
3Adaptability or versatility
If additional transformers are fed from the phase itself, then voltage can be changed, but in the event of undervoltage, the voltage provided by the additional transformer also drops, which is counterproductive for stabilization
Solution Approach 1:
The patent introduces an intermediary power source (energy storage element) that decouples the additional transformer from direct dependence on the unstable grid voltage. The energy storage element acts as a buffer, providing the necessary power to the additional transformer even when grid voltage is low, enabling the transformer to provide stabilizing voltage support.
Solution Approach 2:
The energy storage element is pre-charged during periods of normal or high voltage, storing energy in advance. When voltage drops occur, this pre-stored energy is immediately available to power the additional transformer, allowing it to provide voltage support without being constrained by the undervoltage condition.
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 solution achieves a considerable extension of the voltage range with minimal additional effort and cost, reducing the need for oversized equipment and minimizing installation space, while ensuring efficient operation and reduced losses.
Implementation Method 1
it can increase the voltage of the wind turbine by inducing an additional voltage with the same sign as the voltage emitted by the wind turbine, or reduce it by inducing a voltage with the opposite sign to the wind turbine
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a wind turbine having a wind rotor (12), a generator (14) powered therewith for generating electrical energy, and a connecting line for delivering the electrical energy, optionally via a system transformer (2). The wind turbine is provided with a voltage expander (3) that expands the voltage range of the wind turbine by means of an auxiliary voltage source. The voltage expander (3) comprises a small transformer (30) of its own having a primary and a secondary winding (31, 32), and a switching mechanism (33). The small transformer (30) is looped into the connecting line (17) with the secondary winding (32), and the switching mechanism (33) is connected to the primary winding (31) of the small transformer (30), actuating the primary winding (31) in a switchable multi-stage manner. Thus, a multi-stage expansion of the voltage range of the wind turbine is achieved, wherein thanks to the arrangement of the small transformer lengthwise in the connecting line, the small transformer needs to have only a fraction of the nominal power of the wind turbine.