Magnetic Bearing Position Detection via Current Differential
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Solution Overview
Problem
Magnetic bearings require position sensors for determining positional deviations, which increases complexity and the risk of errors, and they often need multiple power amplifiers, making them less efficient.
Innovation Solution
A magnetic bearing system that uses a first and second magnetization module with coils connected in series and a bias module to levitate a body without contact, detecting positional deviations by measuring the difference in current changes over time without the need for position sensors, utilizing a transformer to directly detect the current difference for position determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If position sensors are used to determine positional deviations in magnetic bearings, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces mechanical position sensors with an electrical measurement system. By measuring current changes in the magnetization modules and processing these signals through evaluation circuits, the system determines positional deviations without physical sensors. This substitution eliminates sensor-related complexity while maintaining measurement capability.
Solution Approach 2:
The magnetic bearing system uses its own operational parameters (current changes in magnetization modules) to determine positional deviations. The system's normal operating signals serve dual purposes: both controlling the magnetic fields and providing information about body position, eliminating the need for separate sensing systems.
2Measurement precision
If multiple power amplifiers are used to control electromagnets, then control precision is improved, but the number of components increases
Solution Approach 1:
The patent combines the functions of multiple power amplifiers into a single amplifier. By using one amplifier to drive both magnetization modules and implementing differential control strategies, the system reduces the number of power amplifiers from multiple to one, thereby reducing component count while maintaining control precision through signal processing.
3Device complexity
If series connection of coils is used, then the number of power amplifiers is reduced, but control flexibility decreases
Solution Approach 1:
The patent implements dynamic control strategies that adapt to the series connection configuration. By using pulse-width modulation and adjusting duty cycles dynamically, the system maintains control flexibility despite the fixed series connection. The control system can independently modulate each coil's effective contribution through timing and signal shaping.
Solution Approach 2:
The patent changes control parameters from independent current control to differential voltage control with pulse-width modulation. This parameter transformation allows the series-connected coils to be controlled flexibly by manipulating voltage pulse widths and timing, effectively compensating for the reduced electrical independence of the coils.
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
Enables the determination of positional deviations without sensors, reducing complexity and the number of power amplifiers required, improving stability and efficiency by leveraging the difference in current changes to balance magnetic forces for levitation.
Implementation Method 1
a first electric current i1 through the first coil 110 induces a first magnetic field and a second electric current i2 through the second coil 210 induces a second magnetic field
Implementation Method 2
A transformer can be used to detect the current difference, which corresponds to the positional deviation
Implementation Method 3
the body 105 inserted into the magnetic bearing is suspended in a contactless state by a balance of magnetic forces
Data Source
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AI summary
A magnetic bearing for contactless holding of a body (105) in at least one direction (R) by means of a magnetic field comprises: a first terminal (11) and a second terminal (12) between which a voltage signal (Uc) can be applied; a first magnetization module (100); a second magnetization module (200); and a premagnetization module (300) which generates a third magnetic field. The first magnetization module (100) comprises a first coil (110) with a first coil end (111) electrically connected to the first terminal (11) and a second coil end (112) electrically connected to the second terminal (12), such that when the voltage signal (Uc) is applied, a first electric current through the first coil (110) induces a first magnetic field.The second magnetization module (200) comprises a second coil (210) with a first coil end (211) electrically connected to the first terminal (11) and a second coil end (212) electrically connected to the second terminal (12), such that when the voltage signal (Uc) is applied, a second electric current through the second coil (210) induces a second magnetic field. The first magnetization module (100), the second magnetization module (200), and the premagnetization module (300) are arranged such that, by controlling the voltage signal (Uc), the body (105) inserted into the magnetic bearing is suspended in a contactless state by a balance of magnetic forces between the first magnetization module (100), the second magnetization module (200), and the premagnetization module (300).