Aircraft Electrical Machine Stator Sensor for Low-Speed Rotor Position
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Solution Overview
Problem
Existing electrical machines for aircraft propulsion face challenges in accurately monitoring rotor position, especially at low speeds and loads, due to the limitations of integrated sensors and sensorless control methods.
Innovation Solution
The electrical machine incorporates a sensor integrated into the stator, with concentrated windings and a sensor coil wound around specific slots, allowing for accurate measurement of rotor position and temperature without the need for a rotating sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a shaft mounted sensor is used to measure rotor position, then measurement precision is improved, but weight increases and reliability decreases
Solution Approach 1:
The sensor is extracted from the rotating shaft and relocated to the stationary stator. This removes the sensor from the harsh rotating environment, improving reliability while maintaining measurement precision through the use of a stationary sensor that can use robust measurement techniques.
Solution Approach 2:
Instead of directly measuring rotor position with a shaft-mounted sensor, the invention uses a sensor coil on the stator to detect the magnetic field signature of the rotor magnets. This indirect measurement approach copies the rotor position information through magnetic field detection, eliminating the need for mechanical shaft sensors.
2Measurement precision
If a shaft mounted sensor is used to measure rotor position, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The sensor coil is merged with the stator structure, utilizing the existing magnetic circuit components. The sensor coil integrates with the stator slots and magnetic circuit, eliminating the need for separate shaft mounting structures and reducing overall device complexity.
Solution Approach 2:
The stator serves multiple functions: it provides the magnetic circuit structure, houses the phase windings, and integrates the sensor coil. This multi-functionality reduces the need for separate components and simplifies the overall machine design.
3Device complexity
If sensorless control laws are used to monitor rotor position, then device complexity is reduced, but measurement precision deteriorates at low speeds and loads
Solution Approach 1:
A sensor coil acts as an intermediary between the rotor magnets and the control system. This intermediary provides direct magnetic field information from the rotor, enabling accurate position measurement without complex sensorless algorithms, particularly at low speeds and loads where back EMF is insufficient.
4Manufacturing precision
If concentrated windings are used in the stator, then manufacturing precision is improved, but device complexity increases due to additional slots for sensor coil
Solution Approach 1:
The sensor coil is placed in the radial dimension between stator slots rather than requiring additional circumferential space. This utilizes the existing radial space in the stator structure, avoiding increases in stator outer diameter while accommodating the sensor coil.
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 configuration reduces the weight and cost of the machine, enhances accuracy and reliability of rotor position monitoring, and provides fault tolerance with redundant sensors.
Implementation Method 1
the voltage induced in the sensor coil can be used to determine the position of the rotor
Implementation Method 2
the rotor's magnetic field is produced by permanent magnets, which induces an AC voltage in the stator windings as the stator windings pass through the moving magnetic field of the permanent magnet
Data Source
AI summary
An electrical machine for use in an aircraft. The electrical machine includes a rotor that includes a plurality of rotor poles, and a stator including a plurality of phases. Each respective phase occupies at least one elementary block. The at least one elementary block of each phase includes a set of conductors of the respective phase wound around a plurality of slots of the respective elementary block in a concentrated winding configuration. The stator further includes at least one sensor located between two elementary block. The at least one sensor being configured to measure at least one parameter of the rotor.