Risley Prism Laser Charging for Faster EV Receiver Location
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Solution Overview
Problem
Conventional remote wireless charging systems for electric vehicles using High Intensity Laser Power Beaming (HILPB) face inefficiencies due to GPS errors, which prolong the time required to locate the Power Receiver (PRX) and photovoltaic panel, as pilot signals can only be transmitted in one direction at a time, increasing the overall power transmission time.
Innovation Solution
A system employing OOFDMA and Risley prisms to transmit pilot signals in multiple directions simultaneously by generating transmission power information for each wavelength using OOFDM, allowing the Risley prisms to rotate and transmit signals to areas where power transmission is available, enabling the receiver to determine the optimal power source and shorten the location-finding time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pilot signals are transmitted in one direction at a time, then the system can accurately locate the PRX and photovoltaic panel, but the time required to find the exact location increases
Solution Approach 1:
The system segments the pilot signal transmission by dividing the signal into multiple wavelength components (e.g., different frequency subcarriers in OFDM). Each wavelength component can be transmitted in a different direction simultaneously through the Risley prisms, allowing the system to cover multiple directions at once while maintaining the ability to identify the optimal direction through wavelength-specific detection at the receiver
Solution Approach 2:
The system adds the wavelength dimension to the traditional single-direction pilot signal transmission. By using multiple wavelengths that can be spatially separated by Risley prisms, the system transforms a one-dimensional (single direction) transmission into a multi-dimensional (multiple directions + multiple wavelengths) transmission, enabling simultaneous multi-directional coverage without sacrificing location accuracy
2Area of stationary object
If the number of directions for pilot signal transmission increases, then the coverage area increases, but the time to transmit all pilot signals increases proportionally
Solution Approach 1:
The pilot signal is segmented into multiple wavelength components, each carrying a portion of the directional information. The Risley prisms spatially separate these wavelength components, allowing simultaneous transmission to multiple directions. This segmentation enables the system to cover a large area without sequentially transmitting signals in each direction, thus avoiding the proportional increase in transmission time
Solution Approach 2:
The system merges multiple directional transmissions into a single multi-wavelength signal that is transmitted simultaneously. By combining the directional information across different wavelengths and using Risley prisms to spatially separate them, the system achieves multi-directional coverage in the time it would take to transmit a single directional signal, thereby expanding coverage area without increasing transmission time
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 time to find the exact location of the PRX and photovoltaic panel, allowing for efficient power transmission by simultaneously transmitting pilot signals in multiple directions, thus enhancing the speed and accuracy of power delivery.
Implementation Method 1
transmitting pilot signals in multiple directions simultaneously by using OOFDM, WDMA, and the Risley prisms
Data Source
AI summary
A system for remote wireless charging for an electric vehicle using OOFDMA and Risley prisms is proposed. The system includes a receiver configured to transmit location of the receiver and photovoltaic panel size information as a power request signal through V2I, and a transmitter configured to control power transmission based on the information on the power request signal, control a distance between the prisms according to the location of the receiver and the size of a photovoltaic panel, transmit transmission power information (PowerInfo) for all laser signals to be received by the photovoltaic panel, and rotate the Risley prisms by a predetermined angle, wherein the transmitter, after generating the transmission power information for each wavelength by OOFDM, transmits the signals to areas where the power transmission is available when the prisms are rotated by the predetermined angle, thereby reducing time to find exact locations of the receiver and photovoltaic panel.