Single-Conductor Aerial Power Tether Using Capacitive Ground Return
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Solution Overview
Problem
Aerial station power tethers face challenges with weight, bulk, and stiffness due to the need for multiple conductors for bipolar current flow, which increases resistance and requires additional insulation at higher voltages.
Innovation Solution
Implementing unipolar current flow using capacitive coupling between the aerial station and a ground plane, eliminating the need for a return conductor and allowing higher voltages without insulation, with a Tesla coil or resonant transformer for voltage boosting and inductive coupling for power extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bipolar current flow with two conductors is used, then electrical circuit continuity is established, but tether weight and bulk increase
Solution Approach 1:
The invention extracts and eliminates one of the two conductors from the bipolar system. By using the ground plane as the return path, only a single conductor is needed in the tether, reducing tether weight and bulk while maintaining complete electrical circuit continuity through the ground connection.
Solution Approach 2:
The ground plane serves multiple functions: it acts as the return conductor for the electrical circuit, provides a reference potential, and eliminates the need for a second conductor in the tether. This multi-functionality resolves the contradiction by using existing infrastructure (ground) to replace additional tether components.
2Productivity
If higher voltages are used to reduce conductor size, then power transmission efficiency improves, but electrical insulation requirements increase tether bulk
Solution Approach 1:
The invention removes the insulation layer from the conductor by using unipolar current flow. Since current flows in only one direction through the single conductor (with return through ground), there is no risk of conductor-to-conductor shorting, eliminating the need for thick insulation and reducing tether bulk while enabling higher voltages.
Solution Approach 2:
The invention changes the current flow parameter from bipolar (alternating directions) to unipolar (single direction), and increases the voltage parameter. This parameter transformation allows higher operating voltages without insulation, directly resolving the contradiction between power efficiency and tether bulk.
3Reliability
If two conductors are used for bipolar current flow, then electrical circuit is complete, but conductor resistance increases with tether length
Solution Approach 1:
The invention extracts one conductor from the system and replaces it with the ground plane connection. This reduces the total conductor length in the tether from two conductors spanning the full distance to a single conductor, directly reducing resistance and energy loss while maintaining circuit completeness through the ground return path.
4Weight of moving object
If single conductor with unipolar current flow is used, then tether weight and bulk are reduced, but voltage boosting requires additional equipment
Solution Approach 1:
The invention introduces a Tesla coil or resonant transformer as an intermediary voltage-boosting device at the aerial station. This equipment transforms the single-phase input into high-voltage unipolar output, enabling the lightweight single-conductor configuration while managing the complexity through a dedicated voltage transformation stage.
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 approach significantly reduces the weight, bulk, and stiffness of the tether while enabling efficient power transmission with reduced conductor size and increased voltage, minimizing parasitic capacitance and power loss.
Implementation Method 1
capacitive coupling between the aerial station and a ground plane (for example, the earth supporting a base station) for the return conductor
Implementation Method 2
A voltage step-up circuit may be supported by the aerial station to boost the voltage between the tether and the capacitor plate structure
Implementation Method 3
inductive coupling for power extraction
Data Source
AI summary
A power tether for aerial devices such as balloons or drones operates with as few as a single conductor, providing a ground return by capacitive coupling between the aerial device and a ground plane at a base station. High-frequency, high-voltage power allows significant power transfer through the low capacitance between the aerial station and the ground minimizing the necessary current flow.