M-Phase Vehicle Pickup Coil Layout for Low-Ripple Wireless Charging
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Solution Overview
Problem
Existing wireless power transfer systems for traveling vehicles experience power ripple due to fluctuations in the relative position of primary and secondary coils, leading to inefficiencies and increased losses in power transmission.
Innovation Solution
A dynamic wireless power transfer system is designed with a plurality of primary coils installed along a road and a secondary coil mounted in the vehicle, where the secondary coil is configured as an M-phase coil with a coil end extending along the front-rear direction and a main coil portion along the width direction, with a higher magnetic resistance for the coil end's magnetic path compared to the main coil portion, to reduce power ripple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a three-phase coil is used for both primary and secondary coils in wireless power transfer, then power transfer capability is improved, but power ripple increases due to relative position fluctuations
Solution Approach 1:
The secondary coil is segmented into M-phase coils (where M is 2 or higher), with each phase having distinct coil ends and main coil portions. This segmentation allows independent optimization of each phase's magnetic path characteristics to reduce power ripple while maintaining overall power transfer capability.
Solution Approach 2:
Different parts of the secondary coil are given different magnetic resistance characteristics. Specifically, the coil ends are designed with higher magnetic resistance than the main coil portions, creating local quality differences that balance mutual inductances and reduce power ripple during relative position fluctuations.
2Adaptability or versatility
If the secondary coil is configured with coil ends extending along the front-rear direction, then adaptability to vehicle motion is improved, but magnetic flux leakage increases
Solution Approach 1:
The magnetic path is designed with locally different resistance characteristics - the coil ends (which extend along the front-rear direction for adaptability) have higher magnetic resistance, while the main coil portions have lower magnetic resistance. This local differentiation allows the coil ends to accommodate vehicle motion while the main portions efficiently conduct magnetic flux.
Solution Approach 2:
The secondary coil structure is made asymmetric with respect to magnetic resistance distribution. The coil ends and main coil portions have deliberately different magnetic resistance values, creating an asymmetric magnetic path that simultaneously achieves motion adaptability and reduces flux leakage.
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 enables efficient power transfer with reduced power ripple, enhancing inverter efficiency and reducing losses by balancing mutual inductances and magnetic flux resistance.
Implementation Method 1
a dynamic wireless power transfer system is provided which is configured to perform, through a plurality of primary coils installed along a traveling direction of a road and a secondary coil mounted in a vehicle, power transfer to the vehicle while the vehicle is traveling
Implementation Method 2
the M coils each being configured such that a magnetic resistance of a magnetic path where a magnetic flux of the coil end passes is higher than a magnetic resistance of a magnetic path where a magnetic flux of the main coil portion passes
Data Source
AI summary
A dynamic wireless power transfer system performs, through a plurality of primary coils installed along a traveling direction of a road and a secondary coil mounted in a vehicle, power transfer to the vehicle while the vehicle is traveling. The secondary coil is an M-phase coil including M coils, M denoting an integer which is two or higher. The M coils each include a coil end extending along a front-rear direction of the vehicle and a main coil portion extending along a width direction of the vehicle, the M coils each being configured such that a magnetic resistance of a magnetic path where a magnetic flux of the coil end passes is higher than a magnetic resistance of a magnetic path where a magnetic flux of the main coil portion passes.