Generator Control Arrangement for Harmonic Loss Mitigation

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Solution Overview

Problem

In wind turbines, reduced channel operation of multiple-channel three-phase PM machines leads to electromagnetic unbalance, resulting in increased harmonic content in electrical and electromagnetic signals, which causes losses and potential overheating of the rotor magnets, limiting power production.

Innovation Solution

A control arrangement that includes a fundamental current controller and a harmonic flux controller to minimize harmonic losses by providing a reference harmonic voltage command, derived from flux linkage signals and electrical angles, to adjust stator currents and reduce harmonic content in the dq-frame, thereby maintaining efficiency and preventing demagnetization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the machine is operated with reduced number of channels, then the device complexity is reduced, but the electromagnetic balance deteriorates and harmonic content increases

Engineering Contradiction:

Improvenumber of channelsVSAvoidelectromagnetic balance

Core Design Contradiction:

Device complexityVSStability of the object's composition

Solution Approach 1:

The control arrangement applies preliminary anti-action by detecting harmonic flux linkages in advance and generating compensating voltage commands before the harmonics cause significant losses or overheating. The harmonic flux controllers continuously monitor the flux linkages and preemptively adjust the voltage commands to counteract the emerging harmonic content, preventing the deterioration of electromagnetic balance rather than reacting after the problem occurs.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The invention changes the control parameters by introducing harmonic flux controllers that specifically target harmonic components in the flux linkages. By adjusting the voltage commands based on detected harmonic flux linkages, the system dynamically modifies operational parameters to maintain electromagnetic balance during reduced channel operation, transforming the control strategy from fundamental frequency only to include harmonic compensation.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If the machine is operated with reduced number of channels, then the device complexity is reduced, but the harmonic losses in rotor magnet increase causing overheating

Engineering Contradiction:

Improvenumber of channelsVSAvoidharmonic losses in rotor magnet

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The control arrangement converts the harmful effect of reduced channel operation into a benefit by using the detected harmonic flux linkages to generate compensating voltage commands. What would normally be harmful harmonics causing losses are instead used as feedback signals to drive the harmonic flux controllers, which produce corrective actions that eliminate the harmful harmonics and reduce energy losses in the rotor magnet.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The system implements feedback by continuously monitoring the flux linkages to detect harmonic content and using this information to adjust the voltage commands. The harmonic flux controllers receive the detected harmonic flux linkages as feedback and generate appropriate compensating voltage commands, creating a closed-loop control system that actively reduces harmonic losses and prevents overheating during reduced channel operation.

Inventive Principle:

Principle #23Feedback

3Device complexity

If the machine is operated with reduced number of channels, then the device complexity is reduced, but the machine output power decreases due to demagnetization risk

Engineering Contradiction:

Improvenumber of channelsVSAvoidmachine output power

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The control arrangement applies beforehand cushioning by detecting harmonic flux linkages early and generating compensating voltage commands to prevent demagnetization before it occurs. The harmonic flux controllers continuously monitor the flux linkages and preemptively adjust the voltage commands to counteract the harmful harmonic effects, protecting the permanent magnets from overheating and demagnetization, thereby preserving the machine's power production capability during reduced channel operation.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 control arrangement effectively reduces harmonic losses in the rotor magnet, preventing overheating and demagnetization, and increases machine output power by minimizing harmonic content in the electrical and electromagnetic signals during reduced channel operation.

Implementation Method 1

a rotation shaft at which plural rotor blades are connected drives a generator in order to generate electric energy

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS10848087B2Control arrangment for a generator

Publication Date: 2020.11.24 SIEMENS GAMESA RENEWABLE ENERGY AS

AI summary

Provided is a control arrangement for controlling an electrical machine, including: a fundamental current controller, at least one harmonic flux controller related to a harmonic of an electrical frequency of the electrical machine, a summation system for adding voltage commands to obtain a summed voltage command based on which the electrical machine.