Wireless Power Transmission Coil Inductance Balancing
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Solution Overview
Problem
Existing wireless power transmission devices face efficiency issues due to differences in inductance values among layered planar coils, leading to impedance imbalance and heat generation, especially when a magnetic substance is present, which reduces transmission efficiency and increases heat.
Innovation Solution
The power transmission device is configured with 2N or M planar coils, where coils with varying inductance values are connected in series and then in parallel, averaging their composite inductance values to maintain balance and reduce resistance loss, thereby enhancing transmission efficiency and minimizing heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the power transmission device is made thinner to reduce space occupation, then the device size is reduced, but the loss of the power transmission coil increases and transmission efficiency decreases
Solution Approach 1:
The power transmission coil is divided into multiple planar coils (first planar coil and second planar coil) with different inductance values. These segmented coils are connected in parallel to achieve an average composite inductance value, which balances impedance and reduces energy loss while maintaining a thin device profile.
Solution Approach 2:
The patent changes the inductance parameter by using planar coils with different inductance values (L1 and L2) instead of identical coils. This parameter variation allows the system to achieve balanced impedance and reduced losses while maintaining the thin device structure.
2Productivity
If planar coils with different inductance values are connected in parallel, then transmission efficiency is improved, but device complexity increases
Solution Approach 1:
The power transmission coil is segmented into multiple planar coils with different inductance values that are connected in parallel. This segmentation allows the system to achieve balanced impedance and improved transmission efficiency while maintaining a relatively simple overall structure.
Solution Approach 2:
The multiple planar coils serve the same function of power transmission but with different inductance characteristics. This multi-functionality approach allows the system to handle impedance balancing and loss reduction while maintaining a unified power transmission objective.
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 reduces current loss and heat generation, improving the overall efficiency of wireless power transmission while maintaining a thin profile, as demonstrated by reduced AC resistance and balanced impedance across coil groups.
Implementation Method 1
a power transmission device that transmits AC electric power noncontact by electromagnetic inductance between a transmission coil and a reception coil
Implementation Method 2
a wireless power transmission system using a resonance power transmission coil and a resonance power receiving coil can maintain high transmission efficiency even if the positions of the power transmission coil and the power receiving coil are deviated
Data Source
Figure 1
Figure 2~3
Figure 4A
AI summary
A power transmission device having a surface a part of which defines a power transmission plane, the device includes: a power transmission circuit converting DC power into AC power; and a power transmission coil structure including 2N planar coils laminated in a direction which is perpendicular to the power transmission plane, the power transmission coil structure wirelessly transmitting the converted AC power to a power receiving coil of a power receiving device via the power transmission plane and being disposed on a side toward the power transmission plane in the power transmission device. The 2N planer coils constitute coil groups including a coil group in which a planar coil having an i'th highest inductance out of the 2N planar coils and a planar coil having an i'th-lowest inductance are connected in series and the coil groups are connected in parallel to each other.