Propulsion Motor Control for Rotor Magnet Demagnetization

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Solution Overview

Problem

Existing propulsion systems fail to adequately manage demagnetization of permanent magnets in motors, leading to potential motor abnormalities and reduced safety in moving objects like eVTOL aircraft.

Innovation Solution

A propulsion system with an information acquisition unit and demagnetization management unit that monitors and manages demagnetization of permanent magnets using driving information, taking proactive measures to prevent demagnetization progression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the motor is driven to propel the moving object, then propulsion function is achieved, but demagnetization of the permanent magnet occurs leading to motor abnormalities

Engineering Contradiction:

Improvepropulsion capabilityVSAvoidmotor safety

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The system performs preliminary demagnetization management by acquiring driving information before motor abnormalities occur. The demagnetization management unit proactively monitors driving states and manages demagnetization progression, preventing motor failures before they happen rather than reacting after damage occurs.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The information acquisition unit continuously monitors driving information (current, voltage, temperature) and feeds this data to the demagnetization management unit. This feedback loop enables real-time detection of demagnetization risks and allows the system to adjust operating parameters to prevent permanent magnet damage while maintaining propulsion.

Inventive Principle:

Principle #23Feedback

2Reliability

If demagnetization management is implemented, then motor safety is improved, but system complexity increases

Engineering Contradiction:

Improvemotor safetyVSAvoidsystem structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The information acquisition unit serves multiple functions: it monitors driving current, voltage, temperature, and other parameters needed for both general motor control and specific demagnetization management. By making this unit multi-functional, the patent avoids adding separate dedicated sensors and processing circuits, thereby limiting the increase in system complexity while achieving comprehensive demagnetization protection.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20260074643A1Propulsion system, propulsion control device, and non-transitory computer readable storage medium

Publication Date: 2026.03.12 DENSO CORP

AI summary

A propulsion system includes a propulsion device and a flight control device. The propulsion device includes a motor. The motor includes a rotor magnet. The flight control device acquires a motor temperature. The flight control device acquires a motor current. The flight control device performs management processing for managing demagnetization of the rotor magnet using driving information such as the motor temperature and the motor current. The management processing includes processing of determining whether a state of the motor is in an abnormal region, a demagnetization region, or a general region. In the management processing, the motor current is limited according to which region the state of the motor is in.