Inductive Energy Transfer Circuit with Post-Stabilization

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Solution Overview

Problem

Current inductive energy transmission systems face complexities due to the need for separate signal feedback channels, which increase design and component complexity, and the coupling-independent operating point restricts system performance and efficiency, especially under varying load conditions and distances.

Innovation Solution

A three-stage concept for inductive energy transmission systems is proposed, eliminating the need for signal feedback by operating the resonant stage at a fixed frequency and adding a post-stabilization stage to condition the output voltage, allowing for a simpler design and improved efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If a separate physical channel is used for signal feedback between primary and secondary sides, then the current electrical state can be known for control purposes, but the structural complexity and component effort increase significantly

Engineering Contradiction:
Improvesignal feedback informationVSAvoidstructural complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent combines the signal feedback function with the existing magnetic coupling channel used for energy transfer. By utilizing the same transformer coupling for both power transmission and control signal feedback, the invention eliminates the need for separate physical channels, thereby reducing structural complexity while maintaining full control capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The magnetic coupling channel is designed to serve dual purposes: transferring energy between primary and secondary sides and simultaneously transmitting control signals for feedback. This multi-functional approach allows the same hardware infrastructure to handle both power and control functions, reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Device complexity

If coupling-independent operating point is used to simplify control, then system performance and efficiency are restricted under varying load conditions and distances

Engineering Contradiction:
Improvecontrol complexityVSAvoidsystem efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The invention implements dynamic control by continuously adjusting the switching frequency based on real-time feedback about load conditions and coupling status. This dynamic adaptation allows the system to maintain high efficiency across varying operating conditions, distances, and load requirements, rather than being constrained to a fixed coupling-independent operating point.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs feedback control where the electrical state information from the secondary side is used to adjust primary side control variables. This closed-loop feedback mechanism enables the system to optimize its performance dynamically, maintaining high efficiency under varying load conditions and distances by continuously adapting to changing operating parameters.

Inventive Principle:
Principle #23Feedback

3Reliability

If galvanic connections are used for power supply, then reliable electrical connection is achieved, but mechanical complexity and vulnerability to environmental influences increase

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidmechanical design complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical galvanic connections with contactless magnetic coupling for power transfer. By using electromagnetic induction through a transformer, the system eliminates the need for physical plugs, cables, and sliding contacts, thereby reducing mechanical complexity while maintaining reliable power supply and improving resistance to environmental influences.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 simplifies the construction of the resonant converter stage, reduces losses, and enables efficient energy transmission with stable output voltage, suitable for modern electronic loads, while avoiding the limitations of coupling-independent operating points.

Implementation Method 1

The core component in the case of contactless, inductive energy transfer is a loosely coupled transformer, which represents the magnetic coupling of a coil in the base unit 102 with a coil in the handset 104 at the circuit level.

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

operating the resonant stage at a fixed frequency

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP2393181B1Circuit for a system for a contactless, inductive energy transfer
Publication Date: 2019.09.04 FRIWO GERAETEBAU GMBH
  • EP2393181B1 patent drawingFigure 1a~1b
  • EP2393181B1 patent drawingFigure 2a~4
  • EP2393181B1 patent drawingFigure 5

AI summary

The circuit has a primary-sided circuit arranged on a primary side and connected with a primary-sided supply voltage. A secondary-sided circuit is connected with a load and includes an after-stabilization stage i.e. linear regulator. A transmission stage includes a resonant converter and a galvanic separation for contactless transmission of energy from the primary side over an air gap away from the secondary side. Two magnetically coupled coils are provided for inductive energy transmission and spatially separable from each other by separating the secondary side from the primary side.