Flux-Switching PM Machine Layout to Reduce Flux Leakage
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Solution Overview
Problem
Flux-switching permanent magnet machines experience higher copper losses, lower performance, low power factor, and high current consumption compared to conventional permanent-magnet synchronous motors.
Innovation Solution
Incorporating at least one secondary permanent magnet in each housing between the base and legs of the U-shaped modules in the active element, which modifies the magnetic flux to minimize leakages and enhance force or torque density and power factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional permanent-magnet synchronous motor design is used, then lower copper losses and higher performance are achieved, but the machine cannot provide high force density or torque density
Solution Approach 1:
The machine is divided into modular U-shaped modules in the active element, each containing windings and working with corresponding passive element modules. This segmentation allows for optimized flux paths and reduced leakage while maintaining high force density, resolving the contradiction between energy losses and force density
Solution Approach 2:
The invention uses localized permanent magnets (both primary and secondary) positioned specifically in the passive element modules to enhance magnetic flux density where needed. This local quality enhancement improves force density without proportionally increasing copper losses, addressing the technical contradiction
2Use of energy by moving object
If conventional permanent-magnet synchronous motor design is used, then lower current consumption is achieved, but the machine has low power factor
Solution Approach 1:
Secondary permanent magnets are pre-positioned in the passive element modules to establish optimal magnetic flux paths before the machine operates. This preliminary magnetic field configuration improves power factor by reducing reactive power requirements, thereby lowering current consumption without compromising manufacturability
Solution Approach 2:
The secondary permanent magnets act as intermediaries that mediate between the primary permanent magnets and the windings, optimizing the magnetic coupling and improving power factor. This intermediary magnetic field reduces the current needed to produce the same electromagnetic force
3Power
If U-shaped modules with windings around teeth are used, then flux-switching operation is achieved, but magnetic flux leakages occur
Solution Approach 1:
Secondary permanent magnets are strategically positioned in specific passive element modules to locally enhance and contain the magnetic flux. This localized flux management reduces leakage paths while maintaining the flux-switching operation in the active element, resolving the contradiction between power operation and flux leakage
Solution Approach 2:
The invention converts potential flux leakage paths into beneficial flux-concentrating paths by positioning secondary permanent magnets to guide and contain the magnetic flux within desired paths. What could be harmful leakage is transformed into useful flux concentration that improves overall machine efficiency
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
The addition of secondary permanent magnets improves the force density in linear machines and torque density in rotary machines, along with the power factor, resulting in a more compact and efficient machine with reduced consumption.
Implementation Method 1
the magnetic flux generated in the flux-switching permanent magnet machine is modified
Implementation Method 2
at least one secondary permanent magnet arranged in each housing
Implementation Method 3
the consecutive primary permanent magnets being magnetized with opposite orientations in the direction of relative movement
Implementation Method 4
The active element comprises a winding around at least one of every two consecutive teeth
Data Source
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AI summary
Flux-switching permanent magnet machine (1) comprising an active element (2) and a passive element (3) which are movable relative to each other in a direction of relative movement. The passive element (3) comprises a plurality of teeth (40). The active element (2) comprises a plurality of U-shaped modules (20) comprising a base (22) and two legs (21) defining a housing (30).The consecutive modules (20) are separated by primary permanent magnets (10), each primary permanent magnet (10) forming a tooth (23) with the adjacent leg (21) of each adjacent module (20). The active element (2) comprises a winding (24) wound around at least one of every two consecutive teeth (23), said winding (24) being partially housed in housings (30) contiguous to the respective tooth (23). The active element (2) comprises at least one secondary permanent magnet (11) arranged in each housing (30).