Wind Turbine Pitch Control for Grid Synchronization
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Solution Overview
Problem
Wind turbine power generating apparatuses face connection failures when connecting to a utility grid due to rapid rotation speed increases, leading to synchronization issues with voltage, frequency, and amplitude, especially during high wind speeds, and low wind conditions that result in disconnection.
Innovation Solution
A wind turbine power generating apparatus with a controller that employs a constant rotation-speed control mode for the pitch drive part to maintain a target rotation speed, reducing the risk of connection failure by controlling the pitch angle changes and ensuring synchronization with the utility grid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the pitch angle is changed from feather side toward fine side to increase rotation speed, then the generator rotation speed reaches connection rotation speed, but the rotation speed increases too rapidly causing synchronization issues with utility grid voltage, frequency, and amplitude
Solution Approach 1:
The controller performs preliminary actions by detecting rotation speed trends before connection and preemptively adjusting the pitch angle change rate. When the rotation speed is predicted to exceed the connection rotation speed by a predetermined amount, the controller reduces the pitch angle change rate in advance, preventing excessive speed increase and ensuring smooth synchronization with the utility grid.
Solution Approach 2:
The controller continuously monitors the generator rotation speed and provides feedback to adjust the pitch angle control. By detecting whether the rotation speed is increasing too rapidly, the controller dynamically adjusts the pitch angle change rate, creating a closed-loop control system that maintains optimal connection conditions.
2Productivity
If the pitch angle is changed at constant rate to reach connection rotation speed, then the generator connects to utility grid, but the rotation speed may decrease to disconnection rotation speed immediately after connection under low wind conditions
Solution Approach 1:
The controller performs preliminary detection of rotation speed trends before connection occurs. By predicting whether the rotation speed may drop below the disconnection rotation speed after connection, the controller preemptively adjusts the pitch angle to maintain adequate rotation speed, preventing immediate disconnection.
Solution Approach 2:
The controller applies beforehand cushioning by maintaining a buffer margin between the connection rotation speed and disconnection rotation speed. When low wind conditions are detected, the controller adjusts the pitch angle to ensure the rotation speed remains sufficiently above the disconnection threshold, providing a safety cushion against speed drops.
3Reliability
If the pitch angle is adjusted to maintain rotation speed at connection rotation speed, then synchronization with utility grid is achieved, but the pitch angle change rate must be limited which extends the time to reach connection
Solution Approach 1:
The controller dynamically adjusts the pitch angle change rate based on real-time rotation speed conditions. During the acceleration phase, a higher pitch angle change rate is applied to quickly approach the connection rotation speed. Near the connection point, the change rate is reduced to ensure precise synchronization, creating a dynamic, adaptive control strategy.
Solution Approach 2:
The controller employs periodic detection and adjustment cycles, monitoring rotation speed at regular intervals and making phased adjustments to the pitch angle. This periodic control approach allows for efficient progression toward connection while maintaining synchronization quality through controlled deceleration phases.
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 effectively reduces the risk of connection failure by maintaining a stable rotation speed and facilitating smooth synchronization with the utility grid, even under varying wind conditions, thereby ensuring stable power transmission.
Implementation Method 1
a wind turbine rotor 2 including at least one blade 3... a generator 7 configured to be driven by rotational energy of the wind turbine rotor 2
Implementation Method 2
a pitch drive part 20 for changing a pitch angle of the at least one blade 3... controlling the pitch angle changes and ensuring synchronization
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A wind turbine power generating apparatus (1) includes: a wind turbine rotor (2) including at least one blade (3); a pitch drive part (20) for changing a pitch angle of the at least one blade (3); a generator (7) configured to be driven by rotational energy of the wind turbine rotor (2); a circuit breaker (10) for switching a connection state of the generator (7) with respect to a utility grid (100); and a controller (30) for controlling the wind turbine power generating apparatus (1). The controller (30) includes: a pitch control part (31) configured to control the pitch drive part (20) in a constant rotation-speed control mode for limiting a change rate of the pitch angle to be not greater than an upper limit value and maintaining a rotation speed of the wind turbine rotor (2) at a target rotation speed corresponding to a connection rotation speed of the generator (7), before the rotation speed of the wind turbine rotor (2) reaches the target rotation speed; and a connection-command generation part (32) configured to provide the circuit breaker (10) with a connection command to connect the generator (7) to the utility grid (100) while the rotation speed of the wind turbine rotor (2) is maintained at the target rotation speed.