Virtual Dynamic Braking in Wind Turbine Power Converters
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Solution Overview
Problem
Wind turbines face wear and damage during grid events due to the time lag in detecting and responding to voltage fluctuations, leading to increased energy dissipation and component stress, which is exacerbated by the need for additional hardware in dynamic braking systems.
Innovation Solution
The implementation of a virtual dynamic braking system that utilizes existing components, such as line side inductors and semiconductor switching devices, to dissipate energy by regulating frequency, thereby increasing losses and eliminating the need for extra hardware, and cooperates with traditional or virtual AC crowbars and DC dynamic brakes to enhance LVRT/ZVRT and wind gust performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional dynamic braking circuits with fast switching devices and resistive devices are used to dissipate energy during grid events, then energy dissipation capability is improved, but device complexity, size, weight, and cost increase
Solution Approach 1:
The patent applies self-service by enabling the power converter's existing components (switching devices and inductors) to perform dynamic braking functions without requiring separate dedicated braking circuits. The controller directs the existing switching devices to operate in a braking mode, allowing the system to dissipate energy using its own built-in components rather than adding external braking equipment.
Solution Approach 2:
The patent implements multi-functionality by making the existing power converter components serve dual purposes: normal power conversion operations and dynamic braking operations. The same switching devices and inductors used for power conversion are repurposed for energy dissipation during grid events, eliminating the need for separate dedicated braking components and reducing overall system complexity.
2Loss of energy
If additional components are added to dynamic braking circuits to improve energy dissipation, then energy dissipation capability is improved, but the size and cost of power converters increase
Solution Approach 1:
The system uses its own existing components (switching devices and inductors) to perform the braking function, eliminating the need for separate external braking resistors or dedicated braking circuitry. This self-service approach allows the power converter to dissipate energy without increasing its physical size or weight.
3Reliability
If control devices detect and respond to grid events quickly, then reliability is improved, but the time lag for sensing and adjustment remains a limitation
Solution Approach 1:
The patent applies preliminary action by pre-configuring the control device and switching devices to be ready for immediate braking operation upon detecting grid events. The controller is programmed with predetermined braking strategies and the switching devices are positioned to可以快速 redirect current during braking, reducing the effective response time by having all components prepared in advance rather than requiring sequential configuration during the event.
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 approach allows for effective energy dissipation without additional components, reducing the size and cost of power conversion devices, while enhancing the system's resilience during grid disturbances and wind gusts.
Implementation Method 1
the switching devices of the dissipative circuit will open and close to transmit DC current to the resistive device, wherein the electric current is dissipated as heat energy
Data Source
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AI summary
A dynamic braking system for an electric power system includes a switching device coupled to an electrical conductor. The switching device is configured to open and close with a plurality of predetermined frequencies. The dynamic braking system also includes an inductive device coupled to the switching device. The power losses of the inductive device are at least partially a function of the plurality of predetermined frequencies. The dynamic braking system further includes a dynamic braking controller coupled to the switching device. The dynamic braking controller is configured to open and close the switching device with at least one of the predetermined frequencies to dissipate electric power from the electrical conductor at a predetermined rate by regulating the power losses of the inductive device as a function of the predetermined frequencies.