Magnetic Suspension Control Using Shared Coil Current Sources
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Solution Overview
Problem
Magnetic suspension systems, such as active magnetic bearing (AMB) systems, face instability due to the increase in magnetic attractive force with a decreasing airgap, requiring a high number of controller current sources for effective levitation, which complicates control and increases costs when centralized, or reduces controllability and stability when decentralized.
Innovation Solution
A control system with a master and slave controller configuration, where the master controller communicates digital data for reference current values to slave controllers, allowing centralized control without the need for a high number of controller current sources, and multiple controllers can connect to the same coil for redundancy and adaptability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high number of controller current sources are used to provide magnetic levitation, then stability and controllability are improved, but device complexity and cost increase
Solution Approach 1:
Multiple controller current sources are merged to share control of the same coil. The first and second controller current sources are both connected to the same coil, allowing them to cooperate in providing the magnetic field, thereby reducing the total number of controllers needed while maintaining stability and controllability.
Solution Approach 2:
The controller current sources are designed to be multi-functional, where each controller can potentially control multiple coils or work in conjunction with other controllers. This universal design allows the system to achieve the required control capability with fewer dedicated controllers.
2Reliability
If a centralized control approach is used to maintain controllability, then stability is improved, but device complexity increases due to the high number of controller current sources
Solution Approach 1:
The control architecture merges multiple controller current sources into a coordinated system where they share control responsibilities. By having controllers work together on the same coil rather than each controller being fully independent, the system maintains centralized controllability with reduced complexity.
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 enables efficient centralized control of magnetic levitation systems, reducing the complexity and cost of power electronics while maintaining stability and controllability, and allows for scalable systems without increasing the number of controller current sources.
Implementation Method 1
a magnetic attractive force acting between a magnet and an object made of e.g. ferromagnetic material increases when an airgap between the magnet and the object gets smaller
Implementation Method 2
at least one of the magnets is a controllable electromagnet
Implementation Method 3
Some systems use permanent magnet material to generate bias magnetic fluxes, while others use direct biasing currents to generate the bias magnetic fluxes. The biasing is used to linearize the operation of the system and to improve control dynamics of the system.
Data Source
Figure 1a~1b
Figure 2
Figure 3a~3b
AI summary
A control system for controlling a magnetic suspension system comprises controllers (101, 102) each being configured to control one or more of magnetic actuators (108-111) magnetically levitating an object (113). One of the controllers is configured to operate as a master controller and other one or ones of the controllers are configured to operate as one or more slave controllers. The master controller is communicatively connected with one or more digital data transfer links (104) to the one or more slave controllers and configured to control operation of the one or more slave controllers. The control system makes it possible to implement a centralized control with separate controllers, and thereby without a need for a controller having a high number of controller current sources.