Radial Electromagnetic Actuator with Segmented Control Poles
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Solution Overview
Problem
Magnetic bearings face challenges in reducing size, weight, and power consumption while maintaining efficient magnetic field generation, particularly in using permanent magnets to support rotating members without mechanical contact.
Innovation Solution
The electromagnetic actuator employs a radial control magnetic pole assembly with permanent magnets and control coils to generate a radial magnetic field, allowing for efficient magnetic flux distribution and exertion of forces on a body without mechanical contact, using a combination of bias and control magnetic circuits to produce controllable radial forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If permanent magnets are used to generate magnetic field in magnetic bearings, then magnetic field generation efficiency is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The magnetic bearing system is divided into multiple independent radial control poles (typically 3-6 poles spaced around the rotor), with each pole having its own permanent magnet and control coil. This segmentation allows the magnetic field to be generated more efficiently through permanent magnets while keeping each pole module relatively simple and modular, thus resolving the contradiction between field generation efficiency and overall device complexity.
Solution Approach 2:
The patent combines permanent magnets with control coils in each radial control pole assembly, merging the advantages of both permanent magnet field generation (higher efficiency) and electromagnetic control (adjustability). This hybrid approach maintains manufacturing feasibility while significantly improving magnetic field generation efficiency compared to using only electromagnetic coils.
2Weight of moving object
If permanent magnets are used to support rotating members without mechanical contact, then weight reduction is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The radial control poles are positioned at specific locations around the rotor with precise angular spacing (e.g., 60 degrees apart for 6-pole configuration), and each pole operates independently with its own control coil. This local control approach allows the system to achieve stable non-contact support while tolerating certain manufacturing variations in other areas, thus reducing overall manufacturing precision requirements despite the need for precise pole positioning.
Solution Approach 2:
The control coils in each radial control pole can dynamically adjust the magnetic field strength and distribution to compensate for manufacturing tolerances and maintain stable rotor support. This dynamic adjustment capability allows the use of permanent magnets for weight reduction while mitigating the impact of manufacturing precision limitations through active control.
3Volume of moving object
If radial control magnetic pole assembly with permanent magnets is used, then size reduction is achieved, but control complexity increases
Solution Approach 1:
The control system is segmented into independent control channels for each radial control pole, with each pole having its own control coil that can be controlled independently. This segmentation allows for compact sizing of the overall system while managing control complexity through modular, independent control of each pole rather than a monolithic control system.
Solution Approach 2:
The control coils in the radial control poles work in conjunction with position sensors (typically capacitive or inductive sensors) to form closed-loop feedback control systems. This feedback mechanism enables precise control of the rotor position and maintains stable operation in a compact configuration, managing control complexity through automated feedback control rather than manual adjustment.
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 solution enables the reduction of size, weight, and power consumption while maintaining effective support of rotating members, achieving efficient and controlled radial electromagnetic forces, suitable for applications in electric machines and other rotating equipment.
Implementation Method 1
A bias magnetic field may be created in air gaps between magnetic radial control poles in a radial control pole assembly and a body using a permanent magnet magnetized along the rotational axis
Implementation Method 2
A control magnetic field may be generated in air gaps between magnetic radial control poles in a radial control pole assembly and a body by inducing control currents in control coils
Implementation Method 3
The magnetic fluxes entering the lateral surface of the body may exert radial forces on the body proportional to the magnetic fluxes in the radial magnetic control circuits
Data Source
AI summary
An electromagnetic actuator can exert a radial electromagnetic force on a body that is configured to rotate about a rotational axis. The actuator includes a radial control magnetic pole assembly that includes radial control poles adjacent to and spaced apart by air gaps from the body. The actuator includes a permanent magnet (PM) magnetized along the axis, having one pole in contact with an axial face of the assembly and located proximate to a lateral surface of the body. The PM is magnetically coupled to the body in a non-contact manner resulting in a bias magnetic flux in the air gaps. The actuator includes a control coil around the radial control poles located radially outwards from the PM. Electrical current in the coils generates control magnetic flux in air gaps. The non-uniform net magnetic flux distribution around the body results in a radial electromagnetic force exerted on the body.