Inductive Power Receiver with Decoupled Coils
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Solution Overview
Problem
Inductive power transfer systems face challenges in maintaining efficient power transfer over varying air gaps and displacements, particularly in lateral directions, which affects the stability and ease of use in applications like electric vehicle charging, requiring improvements in magnetic flux reception and coupling profiles.
Innovation Solution
The design incorporates a bi-polar receiver pad with overlapping, mutually decoupled coils made from aluminium or magnesium, featuring a shielding core and independently tunable and regulated coils to minimize mutual coupling, allowing for efficient flux capture and power transfer with reduced copper usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional inductive power transfer pads are used, then power transfer is achieved, but the system is sensitive to lateral displacements and requires precise vehicle-to-track guidance
Solution Approach 1:
The receiver pad is divided into multiple independently controlled coil assemblies arranged in an array. Each coil assembly can be independently activated or deactivated based on its position relative to the transmitter, allowing the system to maintain stable power transfer over a wider lateral displacement range without requiring precise guidance
Solution Approach 2:
The system dynamically adjusts which coil assemblies are active based on real-time positioning data. As the vehicle moves laterally, different coil assemblies are brought into or taken out of the active set, creating a dynamic reconfiguration that maintains optimal coupling with the transmitter throughout the lateral displacement range
2Use of energy by moving object
If copper windings are used in the receiver pad, then electrical conductivity is achieved, but the device weight and cost increase
Solution Approach 1:
The patent replaces traditional copper windings with aluminium or magnesium windings. These alternative materials are lighter and less expensive than copper, while still providing sufficient electrical conductivity for inductive power transfer applications. The windings are designed as simple conductive structures that achieve the necessary electrical performance without the weight and cost penalty of copper
Solution Approach 2:
The system changes the material parameter from copper to aluminium or magnesium, accepting a slight reduction in electrical conductivity in exchange for significant weight and cost reduction. The winding geometry and turn count are adjusted to compensate for the lower conductivity of the alternative materials, maintaining overall system performance
3Productivity
If coil assemblies are closely spaced to improve flux capture, then power transfer efficiency increases, but mutual coupling between coils increases
Solution Approach 1:
The patent extracts and removes the mutual coupling effect between adjacent coil assemblies by strategically positioning ferromagnetic material. The ferromagnetic strips or blocks are placed between adjacent coils to provide a magnetic flux shunt that redirects flux away from adjacent coils, effectively eliminating mutual coupling while allowing the coils to be closely spaced for improved flux capture from the transmitter
Solution Approach 2:
Ferromagnetic material acts as an intermediary element between adjacent coil assemblies. This intermediary provides a controlled magnetic path that prevents flux from one coil from coupling into adjacent coils, thereby eliminating mutual coupling losses while allowing the coils to maintain close spacing for optimal flux capture from the transmitter
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 configuration achieves stable and efficient power transfer with minimal mutual coupling, enabling effective operation over a wide range of displacements and reducing copper requirements, outperforming traditional designs in many scenarios while maintaining similar performance characteristics.
Implementation Method 1
a receiver which comprises at least one coil arrangement for receiving magnetic flux
Implementation Method 2
a core which comprises a plurality of individual lengths of ferromagnetic material such as ferrite strips or bars
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A magnetic flux pad (BPP) is provided for receiving magnetic flux. The pad may be used with an inductive power transfer system, and comprises a magnetically permeable core (4) and two substantially flat overlapping coils (2, 3) magnetically associated with the core (4).