Wind Turbine Pitch Control Grid Loss Ride-Through
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Solution Overview
Problem
Existing wind turbine pitch control systems struggle to maintain operation during grid loss conditions, particularly on the rotating side of the slip ring assembly, where power supply interruptions can occur, and existing solutions fail to effectively detect and respond to these issues.
Innovation Solution
A method and apparatus for grid loss ride-through in wind turbine pitch control systems that senses and monitors power supply voltage on the rotating side of the slip rings, switching to a backup power source when the voltage drops below a predetermined level, ensuring continuous operation even at 80% or lower AC main voltage for at least three seconds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pitch control system operates during grid loss conditions, then the turbine can maintain safety and grid stability, but the system requires additional backup power sources and monitoring equipment increasing complexity
Solution Approach 1:
The system performs preliminary actions by detecting voltage drops on the rotating side of slip rings before complete power loss occurs, and pre-switches to backup power sources (battery or DC bus) to maintain pitch control operation. This preliminary detection and switching capability ensures reliable operation during grid loss without requiring complex real-time decision systems.
Solution Approach 2:
The invention introduces an intermediary monitoring and control system that detects voltage conditions on the rotating side and mediates between the main AC power source and backup power sources. This intermediary layer manages the switching between power sources and ensures continuous operation, resolving the contradiction by adding intelligent control rather than brute-force redundancy.
2Measurement precision
If voltage monitoring is implemented on the rotating side of slip rings, then accurate detection of power supply issues is achieved, but the system complexity and cost increase
Solution Approach 1:
The monitoring system leverages existing system components and power pathways to perform self-diagnosis. By utilizing the existing voltage supply pathways through the slip rings and integrating monitoring functions into the existing pitch control electronics, the system achieves accurate voltage detection without requiring entirely separate monitoring infrastructure, thus reducing overall complexity.
3Duration of action of moving object
If the system switches to backup power source during voltage drop, then continuous operation is maintained, but response time and switching complexity increase
Solution Approach 1:
The system continuously monitors voltage levels and pre-charges backup power sources before actual power loss occurs. When a voltage drop is detected on the rotating side, the switching to backup power is immediate because the backup sources are already ready, eliminating delays associated with startup or charging sequences.
Solution Approach 2:
The system employs continuous feedback monitoring of voltage levels on the rotating side, with automatic triggering mechanisms that initiate switching when predetermined voltage thresholds are breached. This feedback-driven approach ensures rapid response without requiring complex real-time analysis or manual intervention, maintaining fast switching while ensuring reliable operation.
Data Source
AI summary
In a wind turbine/generator having a rotatable hub, at least one blade rotatably secured to the hub, a pitch control system for adjusting pitch of each blade, the pitch control system located within the rotatable hub, a stationary nacelle, and a slip ring assembly at a junction of an electrical circuit between the rotatable hub and the stationary nacelle, the slip ring assembly operatively arranged for transmission of electrical signals between equipment located within the rotating hub and equipment located within the stationary nacelle, an apparatus for grid loss ride-through for the pitch control system, comprising for example, operational amplifiers for sensing and monitoring power on the rotating side of the slip ring assembly, and, a contactor coil, for example, for supplying power to the pitch control system from a backup power source when the sensed power drops to a predetermined level.