Inductive Battery Charging Resonant Circuit Adaptive Coupling
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Solution Overview
Problem
Existing inductive battery charging systems face inefficiencies when the physical relationship between primary and secondary windings is not precisely predetermined, leading to reduced magnetic coupling and power transfer efficiency, particularly due to increased leakage inductances and poor resonance matching between primary and secondary circuits.
Innovation Solution
The implementation of a system with transmit and receive resonant circuits that operate at matched resonant frequencies, utilizing high-Q coils and capacitors to maintain a strong magnetic field and efficiently couple power, along with adaptive control mechanisms to adjust the drive signal and coil configuration for optimal coupling, regardless of the relative position of the windings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If close and predetermined physical relationship between primary and secondary windings is used, then magnetic coupling is tight and power transfer efficiency is high, but adaptability to various receiving devices is reduced
Solution Approach 1:
The patent implements adaptive impedance matching and resonant frequency tuning that dynamically adjusts system parameters based on the specific receiving device being charged. This allows the system to maintain optimal power transfer efficiency across different device configurations and positions, resolving the contradiction between fixed tight coupling and adaptability.
Solution Approach 2:
The system changes operating parameters including resonant frequency, impedance matching values, and driving frequency to optimize coupling for different receiving devices. By adjusting these parameters adaptively, the system maintains high efficiency without requiring predetermined physical relationships.
2Adaptability or versatility
If precise physical relationship between primary and secondary windings is not predetermined, then adaptability to various devices is improved, but magnetic coupling becomes poor and power transfer efficiency decreases
Solution Approach 1:
The patent incorporates feedback mechanisms that monitor the actual coupling conditions and power transfer efficiency, then adjust driving frequency and impedance matching accordingly. This closed-loop control enables the system to maintain high efficiency even when precise physical relationships are not predetermined.
Solution Approach 2:
The system dynamically adapts its operating characteristics based on real-time detection of receiving device presence and position. Through adaptive impedance matching and resonant frequency adjustment, the system optimizes coupling conditions for each specific configuration.
3Adaptability or versatility
If general physical configuration is used instead of close predetermined coupling, then versatility is improved, but leakage inductance increases and coupling efficiency decreases
Solution Approach 1:
The patent employs parameter changes in resonant frequency and impedance matching to compensate for increased leakage inductance. By adjusting these parameters adaptively, the system maintains effective coupling despite greater physical separation or less precise alignment between windings.
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 power transfer efficiency by maintaining a strong magnetic field and adaptive coupling, even with varying positions of the windings, thereby improving volumetric efficiency and reducing power losses associated with shunting and flux concentration.
Implementation Method 1
the transmit coil is configured to produce alternating current in the transmit coil to generate a magnetic field at about the transmit resonant frequency
Implementation Method 2
transmit resonant circuit that exhibits resonance at a transmit resonant frequency
Implementation Method 3
the receive coil is configured to receive inductively coupled current
Implementation Method 4
transmit resonant frequency and the receive resonant frequency are about equal
Data Source
AI summary
Inductively coupled battery charging systems and methods are provided. Transmit circuitry can include a transmit coil operatively part of a transmit resonant circuit that exhibits resonance at a transmit resonant frequency and an unloaded Q value of at least about 20. Transmit coil can generate a magnetic field at about the transmit resonant frequency. Rechargeable battery assembly can include a receive coil configured to receive inductively coupled current, and circuitry configured to rectify the current and communicate charging power to a storage cell. Receive coil can be part of a receive resonant circuit that exhibits resonance at about the transmit resonant frequency. Transmit circuitry can be configured to detect the rechargeable battery assembly by monitoring a load on the transmit coil.