Resonance Circuit Mutual Inductance Detection for Wireless Power
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Solution Overview
Problem
Determining optimal mutual inductance values for wireless power transmission devices is challenging due to the complexity of circuit elements and varying states of the devices, which affects transmission efficiency.
Innovation Solution
A method and apparatus that utilize a resonance circuit unit with a controller to determine mutual inductance values by supplying power to one transmission resonance circuit while blocking another, using equations to calculate mutual inductance and determine its sign based on received voltages when currents of equal magnitude and phase or out of phase are supplied.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If various circuit elements are considered in the wireless power transmission device, then the determination of mutual inductance becomes more accurate, but the complexity of determining the mutual inductance value increases
Solution Approach 1:
The patent segments the mutual inductance determination process into two distinct phases: first determining the magnitude using power supply to one transmission resonance circuit with blocking of another, then determining the sign by comparing received voltages under in-phase and out-of-phase current conditions. This segmentation simplifies the overall complex determination process while maintaining accuracy by breaking it into manageable steps that account for circuit elements systematically.
Solution Approach 2:
The patent applies preliminary action by first determining the mutual inductance magnitude before determining the sign. The controller first calculates the magnitude using the formula M = (VRq × ZSq) / (ω² × IPt² × RLq) when power is supplied to one transmission resonance circuit, then uses this preliminary result as a basis for subsequently determining the sign through voltage comparison. This preliminary determination simplifies the overall process.
2Productivity
If mutual inductance is not accurately determined, then the wireless power transmission efficiency decreases, but the device operation remains simple
Solution Approach 1:
The patent employs feedback by having the controller compare the received voltages VRq,in-phase and VRq,out of phase from the reception resonance circuit under different current phase conditions. Based on this feedback comparison, the controller determines the sign of mutual inductance (positive or negative), ensuring accurate mutual inductance determination which directly maximizes wireless power transmission efficiency through proper resonance coupling.
3Power
If power is supplied to multiple transmission resonance circuits simultaneously, then the power transmission capability increases, but the mutual inductance determination becomes difficult
Solution Approach 1:
The patent applies dynamics by dynamically switching the power supply state during the mutual inductance determination phase. The controller temporarily supplies power to only one transmission resonance circuit while blocking others to determine mutual inductance magnitude, then switches to supplying power to multiple circuits for normal high-capacity power transmission. This dynamic adjustment allows accurate measurement when needed while maintaining high power transmission capability during operation.
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
Enables rapid and accurate determination of mutual inductance for maximizing wireless power transmission efficiency.
Implementation Method 1
a resonance circuit unit including at least one transmission resonance circuit and at least one reception resonance circuit and configured to transmit power supplied to the transmission resonance circuit to the reception resonance circuit
Implementation Method 2
determine a mutual inductance value related to a transmission resonance circuit to which power is supplied when power is supplied only to any one transmission resonance circuit of the at least one transmission resonance circuit
Data Source
AI summary
Disclosed is a method and apparatus for determining mutual inductance for effective wireless power transmission. The apparatus includes a resonance circuit unit including at least one transmission resonance circuit and at least one reception resonance circuit and configured to transmit power to the reception resonance circuit using power supplied to the transmission resonance circuit, and a controller configured to determine a mutual inductance value related to a transmission resonance circuit to which power is supplied when power is supplied only to any one transmission resonance circuit of the at least one transmission resonance circuit and power supply to another transmission resonance circuit is blocked, and to determine a sign of mutual inductance related to a transmission resonance circuit to which power is supplied when power is supplied only to a reference transmission resonance circuit and any one transmission resonance circuit except for the reference transmission resonance circuit.