Wind Turbine Rotor Speed Control via Dual Setpoints

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Solution Overview

Problem

Existing wind turbine control systems face inefficiencies in transitioning between partial and full load operations, leading to yield losses and increased operating loads, as they struggle to optimize energy production and manage gusts effectively.

Innovation Solution

A method and system that utilize distinct speed setpoints for blade angle and generator torque control, allowing for seamless transition between partial and full load operations by using a third optimal speed setpoint, which is calculated based on current conditions, torque differences, and blade angle deviations, enabling efficient gust detection and optimal power output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single speed setpoint is used for both blade angle control and torque control, then the control system is simple, but energy yield is reduced during transition between partial and full load operations

Engineering Contradiction:
Improveenergy yieldVSAvoidcontrol system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent divides the single speed setpoint into two distinct speed setpoints: a first speed setpoint for blade angle control and a second speed setpoint for torque control. This segmentation allows each controller to operate with optimized parameters in the transition range, improving energy yield without requiring a completely new control architecture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic switching between different speed setpoint configurations. In the transition range from partial to full load, the system uses different speed setpoints for blade angle and torque control. Outside this range, a single speed setpoint is used, reducing complexity when it is not needed.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If pitch control is activated early to maintain constant speed, then speed stability is improved, but aerodynamic efficiency is degraded and energy yield is reduced

Engineering Contradiction:
Improvespeed stabilityVSAvoidaerodynamic efficiency
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The patent prepares both blade angle and torque controllers with their respective speed setpoints before the transition occurs. The first speed setpoint for blade angle control is calculated in advance, allowing the blade angle controller to be ready to take over smoothly when the transition range is reached, avoiding reactive adjustments that would degrade efficiency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the operational parameters of the control system by introducing a first speed setpoint that is optimized for aerodynamic efficiency in the transition range. This allows the blade angle controller to operate with parameters that maximize power capture rather than merely maintaining constant speed.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If torque control is used alone in the transition range, then the control structure is simple, but the system cannot respond effectively to gusts and optimize power output

Engineering Contradiction:
Improvepower output optimizationVSAvoidcontrol structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent merges the functionality of blade angle control and torque control in the transition range by providing both controllers with appropriate speed setpoints. This combination allows the system to leverage both control mechanisms for optimized power capture and gust response, with each controller contributing its strengths.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The control system is designed to be multi-functional by enabling both blade angle and torque controllers to operate simultaneously in the transition range. Each controller serves multiple purposes: the blade angle controller optimizes aerodynamic efficiency while the torque controller manages power extraction, creating a universal control approach that handles various operating conditions.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Productivity

If the speed setpoint is kept constant to simplify control, then control implementation is easier, but the system cannot adapt to varying wind conditions and optimize energy yield

Engineering Contradiction:
Improveenergy yield optimizationVSAvoidcontrol implementation
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent changes the speed setpoint parameter dynamically based on operating conditions. The first and second speed setpoints are calculated differently in the transition range compared to other operating ranges, allowing the system to adapt to varying wind conditions and optimize energy yield without requiring completely different control strategies.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP1893870B8Method and system for regulation of the rotational speed of a rotor on a wind energy unit
Publication Date: 2012.04.11 REPOWER SYST AG

AI summary

The invention relates to a method and a system for regulation of the rotational speed (52) of a rotor on a wind energy unit with a generator and a rotor blade. The first set parameter is a pitch angle (Pitch) of the rotor blade and the second set parameter is the torque of the generator. Said system comprises a pitch angle control or regulation device (32), a torque control or regulation device (33), a first device for determination of a first rotational speed set value (28) (first rotational speed set value determination device (29)) and a second device (26) for determination of a second rotational speed set value (29) (second rotational speed set value determination device (26)). The first rotational speed set value (28) may be supplied to the pitch angle control or regulation device (32) and the second rotational speed set value (29) may be supplied to the torque control or regulation device (33), wherein the first and second rotational speed set value (28, 2)) may be different from each other.