Quadrature Transmitter Pad for Misaligned EV Wireless Charging
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Solution Overview
Problem
Wireless charging systems for electric vehicles face challenges with lateral misalignment between the receiver and transmitter pads, leading to decreased power transfer efficiency and potential safety issues due to leakage electrical fields.
Innovation Solution
The proposed solution involves an improved transmitter pad architecture that includes a first and second auxiliary charging coil, which interoperate with an excitation coil to deliver power to a receiver pad. The power delivery is balanced between the auxiliary coils to automatically steer the magnetic flux towards a misaligned receiver pad, eliminating the need for external guidance mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional single-coil transmitter pad is used, then the system structure is simple, but power transfer efficiency decreases significantly when lateral misalignment occurs
Solution Approach 1:
The transmitter pad is divided into multiple independent coil units (first coil unit, second coil unit, third coil unit, fourth coil unit) arranged in a 2x2 grid pattern. Each coil unit can be independently controlled to generate magnetic flux, allowing the system to segment the power transmission function across multiple units to maintain efficiency under misalignment conditions.
Solution Approach 2:
The system dynamically adjusts the excitation of individual coil units based on real-time detection of receiver pad position and alignment status. When misalignment is detected, the control system modifies which coil units are active and their respective excitation levels, enabling adaptive power transfer that maintains efficiency despite lateral displacement.
2Ease of operation
If the transmitter pad operates with lateral misalignment, then ease of operation is improved, but leakage magnetic field increases causing safety issues
Solution Approach 1:
Different coil units are selectively activated based on the specific misalignment pattern detected. When lateral displacement occurs in a particular direction, only the coil units positioned to compensate for that specific displacement are energized, creating a localized magnetic field correction that maintains safety while accommodating the misalignment.
Solution Approach 2:
The system incorporates detection mechanisms that continuously monitor receiver pad alignment and provide feedback to the control system. Based on this feedback, the control system adjusts the excitation of individual coil units in real-time, creating a closed-loop system that maintains both safety and operational ease by dynamically responding to alignment conditions.
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 enhances the efficiency of wireless power transfer by maintaining a high transfer efficiency even with lateral misalignment, while also reducing leakage magnetic flux density, thereby improving safety.
Implementation Method 1
an excitation coil and a first and second auxiliary charging coil that interoperate together to deliver power
Implementation Method 2
Power delivery from the first auxiliary charging coil and the second auxiliary charging coil is controlled such that electrical power delivery is balanced as between the first auxiliary charging coil and the second auxiliary charging coil to automatically steer (e.g., re-orienting, re-directing, projected, shifting, etc. the overall magnetic field from both auxiliary coils to the receiver pad) a magnetic flux towards a misaligned (e.g., laterally misaligned) transmitter pad
Data Source
AI summary
There is described a wireless power transfer system utilizing a new excitation-quadrature-quadrature transmitter pad which includes one excitation coil and at least two decoupled quadrature auxiliary coils. A described resonant tank design method is proposed for constant-current charging and zero phase angle conditions. When there is a lateral misalignment in the receiver pad, the auxiliary coil that is better coupled with the receiver pad conducts more current than the more distant auxiliary coil does, reducing the leakage magnetic field in the surrounding area and/or improving transmission efficiency.