Wind Turbine Controlled Shutdown via Generator Side Converter
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Solution Overview
Problem
Existing wind turbine shutdown methods using passive resistors can cause wear and tear and unwanted load inversions in the drive train due to discrete power variations, leading to backlashing and oscillations in gearboxes.
Innovation Solution
A method and system utilizing a power converter with a generator side converter acting as an active load, connected to a power dissipation or storage device, to maintain constant drive train torque during shutdown, allowing controlled power dissipation or storage to prevent backlashing and oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If passive resistors with fixed torque curves are used for wind turbine shutdown, then shutdown can be performed, but wear and tear of resistors and unnecessary load on drive train occur
Solution Approach 1:
The patent applies dynamics by transitioning from fixed, passive resistor torque curves to active, variable torque control. The generator side converter dynamically adjusts torque based on real-time operating conditions, allowing optimal shutdown performance while minimizing energy waste and component wear.
Solution Approach 2:
The invention changes the parameter of torque control from fixed to variable. By using the generator side converter to actively modulate torque according to a reference derived from generator torque-speed characteristics, the system achieves efficient shutdown without excessive energy dissipation or mechanical stress.
2Power
If dump load capacity is varied in discrete steps, then power dissipation can be controlled, but load inversions in gearbox may be induced
Solution Approach 1:
The patent implements feedback control where the generator side converter continuously monitors drive train conditions and adjusts torque in real-time. This closed-loop control prevents load inversions by maintaining torque direction stability while achieving precise power dissipation control during shutdown.
Solution Approach 2:
The system uses dynamic torque adjustment through the generator side converter to replace discrete dump load switching. This continuous control mechanism maintains stable torque direction while providing smooth power dissipation control, eliminating the instability caused by stepwise capacity changes.
3Productivity
If active control scheme with generator side converter is used, then shutdown is faster and gentler on drive train, but system complexity increases
Solution Approach 1:
The generator side converter performs multiple functions: it controls shutdown torque, manages power dissipation, prevents load inversions, and protects the drive train. By consolidating these functions into a single active component, the system achieves fast, gentle shutdown without proportionally increasing overall system complexity.
Solution Approach 2:
The patent replaces mechanical torque control mechanisms with electrical control through the generator side converter. This substitution enables precise, rapid torque adjustment for optimized shutdown performance while reducing mechanical wear and simplifying the physical control system architecture.
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
Facilitates a faster and gentler shutdown of wind turbines, reducing wear on the drive train and preventing gearbox backlashing, even during grid faults, by employing an active control scheme with a power converter and intermediate DC circuit.
Implementation Method 1
a power converter comprising generator side and grid side converters being separated by an intermediate DC circuit
Implementation Method 2
dissipating or storing a controlled amount of excess power in the power dissipation or power storage device
Implementation Method 3
power dissipation or power storage device being operatively connected to the intermediate DC circuit
Data Source
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AI summary
The present invention relates to a method for controlled shutdown of wind turbines. The method involves using a generator side converter, and optionally a DC chopper, as a generator load during controlled shutdown. In this way gearbox back-lashing and drive train oscillations can be avoided. The present invention also relates to a wind turbine capable of performing controlled shutdown in accordance with the before-mentioned method.