Wireless Power Transfer Coil Vehicle Detection
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Solution Overview
Problem
Current dynamic wireless charging systems for electric vehicles face challenges in efficiently detecting vehicle presence on high-speed roadways without additional hardware, particularly due to the short duration of vehicle contact with individual charging pads and variability in magnetic topologies between vehicles and charging infrastructure.
Innovation Solution
A method and system that detect changes in coupling between wireless power transfer coils by monitoring induced currents or voltages, using existing coil structures and switches to resonate at specific frequencies, allowing for accurate vehicle detection without external sensors or additional hardware, thereby enabling reliable and robust power transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If individually energised pads are used to reduce power requirements, then power efficiency is improved, but device complexity increases due to requiring multiple inverters and synchronisation systems
Solution Approach 1:
The patent combines the detection and power control functions into a unified system where the detection coil integrated in the de-energised pad serves dual purposes: detecting vehicle presence and controlling power delivery to multiple pads simultaneously, thereby reducing the number of separate inverters and control systems needed
Solution Approach 2:
The de-energised pad is designed to perform multiple functions: it acts as a detection coil to sense vehicle presence, serves as a resonant circuit for signal detection, and controls power delivery to multiple other pads, eliminating the need for dedicated detection hardware and simplifying the overall system architecture
2Reliability
If a continuous magnetic field is generated over long road sections, then reliable power transfer is improved, but power consumption increases due to high VA rating inverters
Solution Approach 1:
The system uses periodic pulsed energisation of individual pads rather than continuous energisation of entire road sections. Each pad is energised only when a vehicle is detected in its vicinity, creating a periodic pattern of power delivery that maintains reliability while dramatically reducing overall power consumption
Solution Approach 2:
The system performs preliminary vehicle detection using the de-energised pad's resonant response before energising power transfer pads. This preliminary detection action allows the system to prepare and energise only the specific pads needed for upcoming vehicles, avoiding wasteful continuous energisation of entire road sections
3Measurement precision
If vehicle detection is performed using additional hardware, then detection accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent makes the de-energised pad multi-functional by using it both as a power transfer component and as a vehicle detection sensor. The pad's resonant circuit properties allow it to detect vehicle presence through changes in its electrical characteristics, eliminating the need for separate detection hardware while maintaining detection accuracy
Solution Approach 2:
The system uses the pad's own resonant response to detect vehicle presence without requiring external sensors or additional detection hardware. The de-energised pad self-services by providing detection capabilities inherent to its electromagnetic structure, reducing overall system complexity
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 allows for efficient and cost-effective detection of vehicle presence, enabling reliable power transfer to electric vehicles moving at high speeds, regardless of magnetic topology variations, without the need for extra hardware, thus enhancing the practicality of dynamic wireless charging.
Implementation Method 1
detecting a current or voltage induced in a de-energised wireless power transfer coil
Implementation Method 2
opening or closing a switch to make the de-energised coil resonant at a required frequency such that the induced current or voltage is resonant
Data Source
AI summary
A method of detecting a wirelessly powered vehicle on a roadway uses detection of induced voltages or currents in coils provided in the roadway. Once the vehicle has been detected the appropriate coils can be energised to power the vehicle.