Wind Turbine Power-Limited Control via Speed and Torque Adjustment

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Solution Overview

Problem

Wind energy installations face challenges in power-limited operation, including unnecessary noise, poor control of wind turbines, and unfavorable torque and speed relationships, leading to excessive loading and inefficient operation.

Innovation Solution

A method for wind energy installations that incorporates rotor blade control, torque control, and a control unit to set and manage a target power value, determining a speed limit and adjusting torque to maintain optimal operation within power-limited conditions, using a characteristic curve to ensure efficient power generation and stable control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the wind turbine operates at rotational speeds corresponding to standard operation in power-limited mode, then the power generation capacity is maintained, but unnecessary noise is generated

Engineering Contradiction:
Improvepower generation capacityVSAvoidnoise
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by adjusting the rotational speed parameter from standard operation values to reduced values appropriate for power-limited mode. The control unit determines a reduced rotational speed setpoint that is lower than the standard operational speed, thereby reducing noise generation while maintaining appropriate power generation capacity for the limited operating conditions.

Inventive Principle:
Principle #35Parameter changes

2Power

If the wind turbine uses torque control and rotor blade control in reduced-power mode, then power output is reduced, but the turbine assumes operating states that lead to unnecessary stress and are difficult to control

Engineering Contradiction:
Improvepower outputVSAvoidcontrol stability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent implements feedback control by continuously monitoring the actual torque and rotational speed, comparing them with the setpoint values determined by the control unit. The control system adjusts the torque control and rotor blade control based on this feedback to maintain stable operating states, preventing excessive stress and ensuring controllable operation in power-limited mode.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies dynamics by making the torque and rotational speed setpoints variable rather than fixed. The control unit dynamically determines appropriate setpoint values based on the power-limited operating conditions, allowing the turbine to adapt its operating parameters in real-time to maintain stability and avoid unfavorable torque-speed combinations that cause stress and control difficulties.

Inventive Principle:
Principle #15Dynamics

3Power

If the wind turbine operates with high rotational speeds in power-limited mode, then power generation potential is maintained, but the torque and speed relationship becomes unfavorable for turbine operation

Engineering Contradiction:
Improvepower generation potentialVSAvoidtorque and speed relationship
Core Design Contradiction:
PowerVSEase of operation

Solution Approach 1:

The patent changes the rotational speed parameter from high values to reduced values that are appropriate for power-limited operation. The control unit calculates and applies a reduced rotational speed setpoint that creates a favorable torque-speed relationship, making the turbine easier to operate and control while still maintaining appropriate power generation potential for the limited conditions.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP1923568B8Method of operating a wind turbine in reduced output power mode
Publication Date: 2013.10.16 NORDEX ENERGY

AI summary

Method for operating a wind turbine with a rotor blade control, a torque control and a control unit which, in a power-limited operating mode, specifies a setpoint for the input power that is less than the rated power, and which, from a limiting speed, reduces the torque by means of the torque control in such a way that the specified setpoint for power is not exceeded, wherein the limiting speed is determined to a value that is less than the rated speed, depending on the specified setpoint for torque.