Rotary Machine Rotor Position Sensing via Magnetic Field Demodulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing rotary machines require a complete measurement chain to detect rotor position, which is cumbersome and occupies space in the machine structure. This motivates the need for a method to detect rotor position without additional sensors, known as sensorless rotor position detection.
Innovation Solution
The rotary machine employs magnetic field sensors arranged stationary relative to the stator, which are designed to detect magnetic field changes and generate signals corresponding to the rotor position. These sensors can be motor coils that both drive the rotor and detect magnetic field changes, eliminating the need for additional sensors. A demodulator unit processes these signals to extract the rotor position information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional sensors are used to detect rotor position, then measurement precision is improved, but device complexity and space requirements increase
Solution Approach 1:
The patent combines the drive function and sensing function into a single integrated system. The motor coils that generate the magnetic field for driving the rotor are simultaneously used as sensors to detect rotor position by measuring back-EMF signals. This merging eliminates the need for separate additional sensors and simplifies the measurement chain while maintaining accurate rotor position detection.
Solution Approach 2:
The motor coils perform multiple functions: they generate the rotating magnetic field necessary for motor operation and simultaneously serve as position sensors by detecting the back-EMF induced by the rotor magnets. This multi-functionality reduces the overall component count and eliminates the need for dedicated sensing components, resolving the contradiction between measurement precision and device complexity.
2Measurement precision
If additional sensors are installed to detect rotor position, then measurement precision is improved, but the space occupied in the machine structure increases
Solution Approach 1:
The sensing function is merged with the existing motor coils, eliminating the need for separate sensor components that would occupy additional space in the machine structure. The same coils that generate the magnetic field are used to detect rotor position through back-EMF measurement, thus maintaining measurement precision without increasing spatial requirements.
3Measurement precision
If a complete measurement chain is used to detect rotor position, then measurement precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent merges the measurement chain with the existing drive system by using the motor coils for both driving and sensing purposes. This integration eliminates the need for separate sensor assemblies, connection wiring, and additional mounting procedures, thereby simplifying the manufacturing process and improving ease of assembly while maintaining accurate rotor position detection.
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 allows for rotor position detection without the need for additional sensors, reducing the complexity and space requirements of the measurement chain while maintaining accurate rotor position sensing.
Implementation Method 1
one or more magnetic field sensors 12 arranged stationary relative to the stator 13 at a radial distance from an axis 20 which is stationary relative to the stator 13
Implementation Method 2
at least one measuring device 1, which is designed to detect magnetic field changes with the aid of the aforementioned magnetic field sensors 12
Implementation Method 3
a rotor 11, which is designed to generate one or more electrical signals 101, 102, 103, 104, 105, 106, 107, 110 in each case with one or more constant magnetic source voltages and with one or more of the magnetic field sensors 12, said signals having signal components which correspond to the rotor rotation frequency 171 and to the distance between the magnetic field sensor 12 and rotor 11 in each case
Implementation Method 4
a demodulator unit 4 which is designed to carry out a demodulation of signals 101, 102, 103, 104, 105, 106, 107, 110, 120, 130 generated by or derived from the magnetic field sensors 12
Data Source
AI summary
The invention relates to a rotary machine comprising a stator and a rotatably mounted rotor, with one or more magnetic field sensors arranged stationary relative to the stator at a radial distance from a stationary axis, at least one measuring device which is configured to detect magnetic field changes with the aid of the aforementioned magnetic field sensors, a rotor which is configured to generate one or more electrical signals in each case, said signals having signal components which correspond to the rotor rotation frequency and to the distance between magnetic field sensor and rotor in each case, wherein a demodulator unit carries out a demodulation of signals generated by or derived from the magnetic field sensors, such that a signal is generated which corresponds to the distance between the rotor and the magnetic field sensor.