Magnetic Bearing Controller Initial Current for Smooth Levitation
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Solution Overview
Problem
Conventional magnetic levitation motor control methods experience excessive vibration and collisions between the rotor and auxiliary bearing at the start of levitation, leading to noise and potential damage.
Innovation Solution
A magnetic bearing controller that generates an initial operation current greater than zero at the start of levitation, using an initial value adder or integrator to ensure a steep rise in electromagnetic force, allowing the rotor to separate promptly from the auxiliary bearing and reduce vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ramp position command value is used at the start of levitation, then the rotor can eventually reach the target position, but excessive vibration and repeated collisions with the auxiliary bearing occur during the transition
Solution Approach 1:
The system performs preliminary action by detecting when the rotor is in contact with the auxiliary bearing and proactively switching to a stepped position command before levitation actually begins. This advance preparation prevents the vibration and collision problems that would occur with a simple ramp command, as the control strategy is adjusted in advance based on the rotor's contact state with the auxiliary bearing.
Solution Approach 2:
The system uses feedback from the rotor position detector to determine whether the rotor is in contact with the auxiliary bearing. This feedback information is used to dynamically switch between different position command strategies (ramp vs. stepped), allowing the system to adapt its control approach based on the actual rotor state and prevent harmful vibrations and collisions.
2Productivity
If the rotor is moved to the target position rapidly, then levitation time is reduced, but the rotor may overshoot and collide with the upper auxiliary bearing
Solution Approach 1:
The system dynamically adjusts the position command strategy based on the rotor's contact state with the auxiliary bearing. When contact is detected, a stepped position command is used to control the levitation speed and prevent overshooting. When no contact is detected, a ramp command can be used for faster positioning. This dynamic adaptation allows the system to achieve both fast levitation and accurate position control without overshooting.
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 effectively suppresses rotor vibration and repeated contact with the auxiliary bearing, ensuring smooth levitation and preventing damage by generating sufficient electromagnetic force for separation.
Implementation Method 1
a pair of electromagnets that causes the rotor to levitate by electromagnetic force
Data Source
AI summary
A magnetic bearing controller for controlling a magnetic levitation motor, the magnetic levitation motor including: a rotor; a pair of electromagnets that causes the rotor to levitate by electromagnetic force; an auxiliary bearing that supports a rotating shaft of the rotor when the rotor is stopped; and a rotor position detector that detects the rotor's position in a levitation direction. The magnetic bearing controller includes an operation current generator that generates an operation current value corresponding to a deviation between a position command value and the rotor's position detected by the rotor position detector. The operation current generator is configured to give a predetermined initial value greater than 0 to the operation current value at a start of levitation for causing the rotor in a state where the rotating shaft of the rotor is supported by the auxiliary bearing to levitate and be positioned at a predetermined target position.