Permanent Magnet Actuator with Opposing Rotor Currents

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Solution Overview

Problem

Existing permanent magnet electromagnetic actuators face limitations in achieving high torque and short reaction time due to the natural limit of magnetic induction field value, which restricts the use of high currents and increases the risk of demagnetization, making it difficult to meet the requirements of high torque and rapid actuation in applications like mechatronic circuit breakers.

Innovation Solution

The design incorporates two superimposed rotor parts with opposite current directions in the same air gap, utilizing radial currents and axial magnetic induction fields, and optimizing the geometry of magnets and driving tracks to maximize Laplace forces while minimizing the risk of demagnetization, allowing for high-intensity currents and high torque without compromising the magnets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If high currents are used to increase motor torque, then torque increases, but the risk of demagnetization of permanent magnets increases

Engineering Contradiction:
Improvemotor torqueVSAvoidrisk of demagnetization
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The rotor is divided into two separate rotor parts (first rotor part and second rotor part) that can be independently controlled. This segmentation allows the currents in the two rotor parts to be configured in opposite directions, creating opposing magnetic fields that cancel each other's demagnetizing effect on the permanent magnets while both contributing to torque production.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines two rotor parts with opposite current directions into a single actuator system sharing the same permanent magnets. The torques from both rotor parts are additive, while their magnetic fields are opposing, creating a synergistic effect that doubles the torque output without increasing the demagnetization risk.

Inventive Principle:
Principle #5Merging (Combining)

2Force

If very high currents are circulated to exceed torque limits, then motor torque increases, but permanent magnets may be demagnetized

Engineering Contradiction:
Improvemotor torqueVSAvoidmagnet integrity
Core Design Contradiction:
ForceVSStrength

Solution Approach 1:

Instead of using a single rotor part with high current that risks demagnetization, the patent inverts the approach by using two rotor parts with opposite current directions. The opposing currents create opposing magnetic fields that neutralize each other's harmful demagnetizing effect while both fields contribute constructively to torque generation.

Inventive Principle:
Principle #13The other way round (Inversion)

3Ease of manufacture

If conventional actuator geometries are used, then design simplicity is maintained, but motor torque is limited by demagnetization risk

Engineering Contradiction:
Improveactuator geometryVSAvoidmotor torque
Core Design Contradiction:
Ease of manufactureVSForce

Solution Approach 1:

The patent adds a dimensional aspect by introducing a second rotor part that operates in the same physical space as the first rotor part. This dual-rotor configuration within the same air gap allows the system to achieve higher torque by utilizing both rotor parts simultaneously with opposite current directions, effectively doubling the torque capability without significantly complicating the overall actuator geometry.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 solution enables the development of a permanent magnet actuator capable of delivering high torque with a long service life and rapid reaction time, overcoming the limitations of existing technologies by allowing high electric currents and reducing the risk of demagnetization, while maintaining low inertia and minimal displacement.

Implementation Method 1

a pole of a magnet of the second series is facing a inverted pole of a magnet of the first series so as to create intense magnetic induction fields in the air gaps thus formed between first and second stator parts

Methodology Applied
Scientific EffectMagnetic induction field: Magnetic Field

Implementation Method 2

an element made of electrically conductive material immersed in a magnetic induction field is subjected, when it is traversed by an electric current, to a driving force oriented in a direction perpendicular to the plane formed by the current and the magnetic induction field

Methodology Applied
Scientific EffectLaplace driving force: Lorentz Force

Data Source

PatentEP2795649B8Electromagnetic actuator comprising permanent magnets and mechanical load interrupter actuated by such an actuator
Publication Date: 2016.03.09 GENERAL ELECTRIC TECH GMBH

AI summary

The invention relates to a novel electromagnetic actuator comprising permanent magnets and having improved tripping speed and motor torque in relation to those of the prior art. The main use of the invention is the actuation of an electro-mechanical load interrupter specifically to carry out the sectioning operations of a mechatronic circuit breaker intended to interrupt high currents at high voltage.