IPM Generator Control Scaling Factor for Loss Reduction

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Solution Overview

Problem

Interior Permanent Magnet (IPM) generators face inefficiencies due to suboptimal rotor and stator geometry, leading to higher power losses and increased cooling requirements, which adversely affect the cost of energy and converter losses.

Innovation Solution

A method for operating IPM generators involves determining a magnetic field reference parameter and a scaling factor to adjust air-gap magnetization, reducing losses by optimizing copper and core losses, and fine-tuning the scaling factor based on temperature measurements to minimize power loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If standard MTPA control is used for IPM generators, then the control system is simple to implement, but generator efficiency is reduced due to suboptimal rotor and stator geometry

Engineering Contradiction:
Improvecontrol system complexityVSAvoidgenerator power loss
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent changes the control parameter from standard MTPA to a modified control strategy that incorporates a scaling factor applied to the magnetization flux reference. This parameter adjustment optimizes the air-gap magnetization level to reduce generator losses while maintaining reasonable control complexity. The scaling factor is determined based on generator loss minimization criteria, transforming the control approach to achieve better efficiency without excessive complexity.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If generator geometry is optimized for maximum efficiency, then power loss is reduced, but the generator design becomes more complex and costly

Engineering Contradiction:
Improvegenerator power lossVSAvoidrotor and stator geometry complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent replaces physical geometry optimization with a control-based solution. Instead of redesigning the rotor and stator geometry to achieve optimal magnetic field distribution, the invention uses a scaling factor in the control system to adjust the magnetization flux reference. This substitutes complex mechanical design modifications with a simpler control parameter adjustment, achieving loss reduction without increasing manufacturing complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Power

If higher current is used to compensate for generator losses, then power output is maintained, but converter losses and cooling requirements increase

Engineering Contradiction:
Improvepower outputVSAvoidconverter loss and cooling power
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent applies preliminary action by optimizing the magnetization flux reference before power conversion occurs. The scaling factor is applied to the magnetization flux reference in the generator control, which reduces generator losses upstream. This prevents the need to compensate with higher currents later, thereby reducing converter losses and cooling requirements before the problem propagates through the system.

Inventive Principle:
Principle #10Preliminary action

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

This approach enhances generator efficiency by minimizing power losses, reducing temperature, and optimizing the stator flux/current vector distribution, thereby improving the overall performance and reducing operational costs.

Implementation Method 1

an electromechanical generator, the method comprising, determining a magnetic field reference parameter based on an electromagnetic power reference representing a desired output of the electromechanical generator

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

determining a scaling factor for adjusting an air-gap magnetization level of the electromechanical generator to reduce loss in operating the electromechanical generator, modifying the magnetic field reference parameter with the scaling factor

Methodology Applied
Scientific EffectMagnetic field scaling: Magnetic Field

Data Source

PatentEP2477325B1Method for operating an electromechanical generator
Publication Date: 2019.04.24 VESTAS WIND SYSTEMS AS
  • EP2477325B1 patent drawingFigure 1
  • EP2477325B1 patent drawingFigure 2
  • EP2477325B1 patent drawingFigure 3

AI summary

According to an embodiment of the present invention, a method for operating an electromechanical generator is provided, the method comprising: determining a magnetic field reference parameter based on an electromagnetic power reference representing a desired output of the electromechanical generator, determining a scaling factor for adjusting an air-gap magnetization level of the electromechanical generator to reduce loss in operating the electromechanical generator, modifying the magnetic field reference parameter with the scaling factor; and operating the electromechanical generator based on at least the modified magnetic field reference parameter.