Inductive Link Coil Electrostatic Shield for Parasitic Variation Compensation
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Solution Overview
Problem
Inductive power transfer and communication systems are susceptible to parasitic variations, which reduce efficiency and require large, costly components to handle high currents and voltages, limiting their resistance to external interference and longevity.
Innovation Solution
An electrostatic shield is inductively coupled with the coil, configured as an open circuit, to protect the coil from parasitic effects and allow signal processing elements to operate on the coil, reducing the stress on components and improving system resilience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If frequency shifting or active re-tuning is used to address parasitic variations, then the inductive link efficiency is improved, but the system cannot operate at very fixed frequencies required by regulatory standards
Solution Approach 1:
An electrostatic shield is introduced as an intermediary component between the primary coil and the external environment. The shield comprises conductive material with gaps that allow it to block parasitic electric fields while permitting magnetic field coupling. This mediator protects the inductive link from parasitic variations caused by nearby conductive objects or tissue, maintaining efficiency without requiring frequency shifts that would violate fixed frequency regulations.
2Power
If large currents and voltages are used in the coils, then power transfer capability is improved, but the size, cost, and stress on modulation and demodulation components increase
Solution Approach 1:
The electrostatic shield acts as a mediator that isolates the high-voltage primary coil from parasitic effects, allowing the use of smaller, less expensive modulation and demodulation components. By blocking parasitic electric fields, the shield reduces the stress on these components, enabling them to be smaller and more cost-effective while still handling the necessary power levels.
3Object-affected harmful factors
If the electrostatic shield is made as a continuous closed circuit, then shielding effectiveness is improved, but inductive coupling with the coil is lost
Solution Approach 1:
The electrostatic shield is segmented into multiple conductive sections with gaps between them. This segmentation allows the shield to block parasitic electric fields (since the gaps prevent continuous current flow) while still permitting magnetic field lines to pass through and induce current in the primary coil. The segmented structure thus simultaneously achieves both shielding effectiveness and inductive coupling.
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 solution enhances the resistance of inductive power transfer and communication systems to parasitic variations, reducing component stress and costs, while maintaining efficiency and longevity.
Implementation Method 1
The electrostatic shield is inductively coupled with the coil and is configured as an open circuit
Data Source
AI summary
An inductive wireless power transfer and communication system includes an electrostatic shield for one of the coils. The electrostatic shield is inductively coupled with the coil and is configured as an open circuit. A signal processing element or elements, especially a modulator or a demodulator, are connected across the electrical discontinuity in the electrostatic shield. Because the electrostatic shield is inductively coupled to the coil, the modulator or demodulator can operate on the signal on the coil. A variable impedance element is connected across the electrical discontinuity in the electrostatic shield. Because the electrostatic shield is inductively coupled to the coil, the variable impedance element can tune the impedance of the system.