Wireless Power Receiving Circuit With Inductance Compensation
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Solution Overview
Problem
Existing wireless power transfer systems face challenges in maintaining stable power transfer due to variations in the number of power transfer targets, leading to inappropriate power transfer and inefficiency.
Innovation Solution
A power receiving device equipped with a compensation element that cancels out variations in the inductance of the power transmitting coil, ensuring stable power transfer regardless of the number of power transfer targets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of power receiving coils varies to match mobile bodies moving along the power transmitting coil, then the system adapts to different power transfer targets, but circuit constants vary causing inappropriate power transfer and inefficiency
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the resonant frequency of the power transmitting coil to match the resonant frequency of the power receiving coil, regardless of the number of receiving coils. This frequency matching maintains stable power transfer by ensuring optimal magnetic coupling conditions are always met, resolving the contradiction between adaptability and reliability.
2Reliability
If a circuit with capacitor and switching element is added to control capacitive reactance according to the number of mobile bodies, then desired circuit operation is achieved, but the system becomes more complex and output varies due to detection delay
Solution Approach 1:
The patent employs self-service by enabling the power transmitting coil to automatically adjust its resonant frequency based on the load conditions detected by the power receiving coil. The receiving coil sends feedback signals that trigger frequency adjustment in the transmitting coil, eliminating the need for complex switching circuits and capacitors while maintaining stable operation.
3Reliability
If the resonant frequency of the power transmitting coil is adjusted to match the power receiving coil, then stable power transfer is maintained across different positions, but the system requires frequency control capability
Solution Approach 1:
The patent implements feedback by using the load detection signal from the power receiving coil to automatically adjust the resonant frequency of the power transmitting coil. This closed-loop control ensures the transmitting coil's frequency continuously matches the receiving coil's frequency, maintaining stable power transfer while the control system handles the complexity automatically.
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
The solution enables stable and efficient power transfer by maintaining constant resonant conditions in the power-transmitting resonant circuit, eliminating the need for complex load detection and control systems.
Implementation Method 1
a power transmitting source to generate a high frequency voltage and a power-transmitting resonant circuit with a power transmitting coil to generate an AC magnetic flux by resonance when receiving the high frequency voltage
Implementation Method 2
a power-receiving resonant circuit to receive the AC magnetic flux transmitted from the power-transmitting resonant circuit and convert the AC magnetic flux into AC power
Implementation Method 3
a power-transmitting resonant circuit with a power transmitting coil to generate an AC magnetic flux by resonance when receiving the high frequency voltage
Data Source
AI summary
A power receiving device and a wireless power transfer system including the same for non-contact power transfer to a plurality of mobile bodies are obtained, which allow stable power transfer even when the number of power transfer targets varies. In the wireless power transfer system, electric power is transmitted from a power transmitting source in a power transmitting device to generate a high frequency voltage and a power-transmitting resonant circuit with a power transmitting coil to generate an AC magnetic flux by resonance when receiving the high frequency voltage. A power-receiving resonant circuit receives the AC magnetic flux transmitted from the power-transmitting resonant circuit and converts the AC magnetic flux into AC power. At least one compensation element cancels out a variation of an inductance of the power transmitting coil attributable to the movement of the power-receiving resonant circuit to a position where electric power can be received.