Pull-Pull Electromagnetic Actuator Without Magnetic Bias Lock-Up
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Solution Overview
Problem
Existing electromagnetic actuators require magnetic bias from current or permanent magnets, leading to inefficiencies and potential 'lock up' issues, especially when generating wide band forces with a large ratio of peak force to RMS force.
Innovation Solution
The development of electromagnetic actuators that produce bidirectional linear force output without magnetic bias from current or permanent magnets, utilizing a coil assembly with inner and outer flux cylinders, top and bottom electrical coils, and magnetic flux sensors to measure and control the force across axial air gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If magnetic bias is provided by current-conducting drive coils, then bidirectional linear force output is achieved, but power consumption increases significantly and efficiency decreases
Solution Approach 1:
The patent extracts and removes the magnetic bias requirement from the actuator system. By eliminating permanent magnets and bias windings, the design achieves bidirectional force without the continuous power consumption associated with maintaining magnetic bias flux. The force is generated purely by the interaction of coil currents with the magnetic circuit, allowing efficient bidirectional operation.
Solution Approach 2:
The patent employs periodic alternation of coil currents to achieve bidirectional force. By switching current direction between opposing coils in a periodic manner, the actuator generates linear force in both directions without requiring continuous magnetic bias. This periodic action allows the system to operate efficiently across the full force range.
2Loss of energy
If magnetic bias is provided by permanent magnets, then efficiency improves, but 'lock up' issues occur when gaps close to zero width
Solution Approach 1:
The patent extracts and removes permanent magnets from the actuator design. By eliminating the permanent magnetic bias source, the system avoids the lock-up problem that occurs when air gaps close to zero width. The magnetic circuit is designed to rely on coil-generated flux rather than permanent magnet bias, ensuring reliable operation across all gap conditions.
Solution Approach 2:
The patent creates a dynamically controllable magnetic circuit where flux levels are adjusted by coil currents rather than fixed by permanent magnets. This dynamic approach allows the magnetic bias to be varied or eliminated as needed, preventing lock-up conditions while maintaining efficiency during normal operation.
3Force
If magnetic bias is maintained high to generate peak force, then peak force capability is achieved, but power consumption increases during low force output
Solution Approach 1:
The patent implements dynamic control of magnetic flux levels through coil currents. The system adjusts flux levels in real-time based on the required force output, maintaining high flux only when peak force is needed. This dynamic adjustment eliminates the waste of maintaining high bias flux during low-force operations, significantly improving overall productivity and efficiency.
Solution Approach 2:
The patent changes the operational parameters of the magnetic circuit by varying coil currents to match the required force output. Rather than maintaining fixed high bias levels, the system dynamically adjusts current magnitude and direction, changing magnetic flux parameters to optimize both peak force capability and operational efficiency across different operating conditions.
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 achieves improved electromagnetic actuator performance and efficiency by eliminating the need for magnetic bias, reducing power consumption, and preventing 'lock up' issues, while maintaining bidirectional linear force output.
Implementation Method 1
top and bottom electrical coils located radially between the inner and outer flux cylinders
Implementation Method 2
generating pull force across a gap that is quadratic with respect to the total flux crossing the gap
Implementation Method 3
top and bottom magnetic flux sensors positioned to measure magnetic flux crossing the respective top and bottom axial air gaps
Data Source
AI summary
Electromagnetic actuators are provided, which generate bidirectional linear force output without magnetic bias from current or permanent magnets. Systems and methods based on the electromagnetic actuators are also provided.