Wind Turbine DC Link Controller for Grid Fault Load Mitigation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wind turbines experience severe mechanical loads and oscillations during grid faults, leading to increased maintenance costs and reduced lifespan due to sudden increases in electromagnetic torque and over-speeding, which existing designs struggle to mitigate effectively.
Innovation Solution
An electrical system comprising a first resistive element, a storage element, and a controller coupled to the DC link of the wind turbine, which switches between these elements in response to grid side faults to minimize mechanical loads by controlling peak electromagnetic torque and oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the pitch control unit increases the pitch angle rapidly to reduce mechanical loads during grid faults, then the mechanical loads are reduced, but severe oscillations occur in wind turbine components especially the tower
Solution Approach 1:
The controller detects grid faults and activates the resistive element before severe oscillations can develop, preemptively controlling the electromagnetic torque to prevent the harmful pitch angle changes that would cause tower oscillations
Solution Approach 2:
The resistive element acts as an intermediary between the generator and the grid, providing a controlled path for energy dissipation that mediates the harmful interaction between grid faults and the pitch control system, preventing oscillations while still reducing mechanical loads
2Reliability
If wind turbine components are designed to withstand peak electromagnetic torque up to three times nominal operating torque, then reliability during grid faults is improved, but device size and cost increase
Solution Approach 1:
The resistive element provides beforehand cushioning by being pre-configured to absorb and dissipate excess electromagnetic torque during grid faults, protecting the gearbox from peak torques without requiring the gearbox itself to be oversized
Solution Approach 2:
The harmful peak torque is extracted from the power transmission path by diverting it through the resistive element, separating the fault management function from the gearbox and allowing the gearbox to be designed for normal operating conditions
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 effectively reduces mechanical loads and oscillations, enhancing the wind turbine's ability to withstand peak electromagnetic torque, thereby reducing maintenance costs and extending the turbine's lifespan while maintaining continuous operation.
Implementation Method 1
The first resistive element and the storage element are coupled to a DC link of the wind turbine. The controller is used for switching between the first resistive element and the storage element in response to a grid side fault condition to minimize mechanical loads induced by the grid side fault condition.
Implementation Method 2
The first resistive element and the storage element are coupled to a DC link of the wind turbine. The controller is used for switching between the first resistive element and the storage element in response to a grid side fault condition.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An electrical system for controlling a wind turbine is provided. The electrical system includes a first resistive element, a storage element and a controller. The first resistive element and the storage element are coupled to a DC link of the wind turbine. The controller is used for switching between the first resistive element and the storage element in response to a grid side fault condition to minimize mechanical loads induced by the grid side fault condition.