Inertial Sensor Wireless Rotor Temperature and Position Detection

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Solution Overview

Problem

Current sensor systems for determining rotational properties and temperatures of rotating elements in electric machines are bulky, costly, and lack redundancy, with limited temperature measurement capabilities, especially for rotor temperatures, which affects performance and safety.

Innovation Solution

A sensor system combining inertial sensors with micromechanical acceleration and yaw rate sensors, and temperature sensors, along with an inductive position sensor, to detect rotational properties and temperatures, using wireless communication and energy harvesting, and featuring a flexible circuit carrier and application-specific integrated circuits for signal processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If resolvers are used to determine rotor position, then rotational property detection is achieved, but device size, cost, and complexity increase

Engineering Contradiction:
Improverotor position detection accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical resolver system with an inertial sensor that uses MEMS (Micro-Electro-Mechanical Systems) technology. This substitution eliminates the need for complex mechanical components like exciter coils and receiver coils, while achieving comparable or superior measurement precision through microelectronic means.

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

Solution Approach 2:

The patent changes the operating parameters by using piezoelectric or capacitive sensing mechanisms instead of electromagnetic induction. This allows for miniaturization and integration of the sensor system while maintaining detection accuracy through alternative physical principles.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If resolvers are used to determine rotor position, then rotational property detection is achieved, but manufacturing cost increases

Engineering Contradiction:
Improverotor position detection accuracyVSAvoidsensor system manufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces the mechanical resolver system with an inertial sensor that uses MEMS (Micro-Electro-Mechanical Systems) technology. This substitution eliminates the need for complex mechanical components like exciter coils and receiver coils, while achieving comparable or superior measurement precision through microelectronic means.

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

Solution Approach 2:

The patent changes the operating parameters by using piezoelectric or capacitive sensing mechanisms instead of electromagnetic induction. This allows for miniaturization and integration of the sensor system while maintaining detection accuracy through alternative physical principles.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If resolvers are used to determine rotor position, then rotational property detection is achieved, but sensor availability decreases due to lack of redundancy

Engineering Contradiction:
Improverotor position detection accuracyVSAvoidsensor availability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent merges multiple sensing functions (acceleration, velocity, position, and temperature detection) into a single integrated inertial sensor module. This consolidation inherently provides redundancy through multiple sensing elements within the same device, improving reliability without increasing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

4Temperature

If temperature sensors are wound in stator coils, then stator temperature detection is achieved, but rotor temperature measurement capability is lost

Engineering Contradiction:
Improvestator temperature detectionVSAvoid rotor temperature measurement information
Core Design Contradiction:
TemperatureVSLoss of information

Solution Approach 1:

The patent makes the inertial sensor multi-functional by enabling it to detect both mechanical parameters (acceleration, velocity, position) and thermal parameters (temperature). This universal sensor replaces multiple dedicated sensors, providing both stator and rotor temperature measurement capabilities while reducing overall system complexity.

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

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 system provides accurate and reliable detection of rotational properties and temperatures, enhancing functional safety, reducing size and cost, and enabling monitoring of rotor conditions without external magnetic field influence, with no speed limitations.

Implementation Method 1

at least one device (134) of at least one inertial sensor (132), which is set up to detect at least one mechanical variable of the rotating element (114)

Methodology Applied
Scientific EffectMicromechanical acceleration sensing: Accelerometer

Implementation Method 2

the inertial sensor (132) has at least one device (134) of at least one inertial sensor (132), which is set up to detect at least one mechanical variable of the rotating element (114)

Methodology Applied
Scientific EffectMicromechanical yaw rate sensing: Accelerometer

Implementation Method 3

the inertial sensor (132) has at least one temperature sensor (140) which is set up to detect at least one temperature of the rotating element (114)

Methodology Applied
Scientific EffectTemperature sensing: Thermocouple

Implementation Method 4

An alternating voltage signal is applied to the exciter coil and it permeates the entire arrangement with an alternating electromagnetic field. Depending on the angle of rotation, a sinusoidal amplitude-modulated voltage can be induced in a first receiver coil

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3833935B1Sensor system for determining the temperature and at least one rotation characteristic of an element rotating about at least one axis of rotation
Publication Date: 2022.08.10 ROBERT BOSCH GMBH
  • EP3833935B1 patent drawingFigure 1A~1C
  • EP3833935B1 patent drawingFigure 2~3
  • EP3833935B1 patent drawingFigure 4

AI summary

The invention relates to a sensor system (110) for determining the temperature and at least one rotation characteristic of an element (114) rotating about at least one axis of rotation (112). The sensor system comprises: i) at least one inertial sensor (132), the inertial sensor (132) having at least one device (134) which is designed to detect at least one mechanical variable of the rotating element (114), the inertial sensor (132) also having at least one temperature sensor (140) which is designed to detect at least one temperature of the rotating element (114), the inertial sensor (132) having at least one first evaluation unit (142) which is designed to generate at least one first signal (144) which contains at least one item of information about the detected temperature and at least one second signal (146) which contains at least one item of information about the detected mechanical variable; ii) at least one inductive position sensor (124) which is designed to detect at least one item of information about the rotation characteristic of the rotating element (114); iii) at least one second evaluation unit (130); characterised in that the inertial sensor (132) has at least one first interface (149) which is designed to transmit the first signal (144) and the second signal (146) wirelessly to the inductive position sensor (124), wherein the inductive position sensor (124) has at least one second interface (180) which is designed to receive the first signal (144) and the second signal (146), wherein the inductive position sensor (124) has at least one third interface (182) which is designed to transmit the first signal (144) and the second signal (146) and the information about the rotation characteristic to the second evaluation unit (130).