Electrostatic Shield for Inductive Link Coil De-tuning
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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, leading to increased weight and reduced longevity.
Innovation Solution
An electrostatic shield is inductively coupled with the coil, configured as an open circuit to protect it from external parasitic effects, allowing modulators and demodulators to operate on the coil signal while minimizing component stress and size.
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 element between the primary and secondary coils. The shield comprises conductive material with gaps that allow it to block parasitic electric fields while maintaining inductive coupling. This mediator structure reduces parasitic variations without requiring frequency shifting or active re-tuning, thus preserving both efficiency and fixed frequency operation capability
2Power
If large currents and voltages are used in the coils, then power transfer capability is improved, but the modulation and demodulation components increase in size, cost, and stress levels
Solution Approach 1:
The electrostatic shield acts as a mediator that reduces parasitic effects, allowing the system to achieve efficient power transfer with reduced current and voltage stress on modulation and demodulation components. By blocking parasitic electric fields, the shield enables smaller, less costly components to handle the power signal effectively
3Object-affected harmful factors
If the electrostatic shield is configured as a closed circuit, then shielding effectiveness is improved, but inductive coupling with the coil is reduced
Solution Approach 1:
The electrostatic shield is segmented by introducing gaps in the conductive material. These gaps prevent continuous current flow while maintaining the shield's ability to block parasitic electric fields. The segmented structure reduces inductive coupling losses compared to a fully closed circuit configuration, achieving a balance between shielding effectiveness and energy 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 solution enhances resistance to parasitic variations, reduces component stress, and minimizes the size and weight of the system, improving efficiency and longevity.
Implementation Method 1
An electrostatic shield is inductively coupled with the coil, configured as an open circuit to protect it from external parasitic effects
Data Source
Figure 1A
Figure 1B~1D
Figure 1E~1G
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.