Non-contact Charging Control via Load Modulation
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Solution Overview
Problem
Existing non-contact charging systems face challenges in charging multiple power receiving terminals with different charging patterns using a common power transmission terminal, often resulting in increased size and heat generation due to the need for individual charging control circuits in each terminal.
Innovation Solution
A non-contact charging system where the charging control unit is integrated into the power transmission terminal, allowing it to adjust the near-electromagnetic field based on reference information from the power receiving terminal, enabling appropriate charging patterns for various batteries while reducing the size and heat production of the power receiving terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a charging control circuit is disposed in each power receiving terminal to achieve appropriate charging patterns, then charging control capability is improved, but device complexity and size increase
Solution Approach 1:
The charging control circuit is extracted from the power receiving terminal and relocated to the power transmission terminal. The power transmission terminal now contains the charging control unit that communicates with the power receiving terminal via load modulation, separating the control function from the receiving terminal to reduce its complexity while maintaining charging control capability
Solution Approach 2:
Load modulation communication serves as an intermediary mechanism between the power transmission terminal's charging control unit and the power receiving terminal. This allows the control unit to manage charging parameters for multiple terminal types without requiring complex hardware in each receiving terminal
2Manufacturing precision
If individual charging control circuits are provided for each power receiving terminal type, then charging pattern accuracy is improved, but adaptability decreases
Solution Approach 1:
The power transmission terminal's charging control unit is designed with universal functionality to handle multiple types of power receiving terminals. By using load modulation communication to exchange charging pattern information, a single control unit can adapt to different battery types (lithium-ion, nickel-cadmium, electric double layer capacitor, nickel-hydrogen) without requiring dedicated control circuits for each type
3Reliability
If power receiving terminals include complete charging control functionality, then charging reliability is improved, but heat generation increases
Solution Approach 1:
The charging control unit is extracted from the power receiving terminal and placed in the power transmission terminal. This relocation removes the heat-generating control circuitry from the compact receiving terminal, reducing its heat generation while maintaining charging reliability through the transmission terminal's control unit that communicates via load modulation
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 charging of multiple power receiving terminals with different charging requirements using a single power transmission terminal, minimizing the size and heat generation of the receiving terminals, and allowing for updates to support new battery types through processing programs.
Implementation Method 1
a power transmission unit that excites a near-electromagnetic field based on an alternating current signal
Data Source
AI summary
In a power transmission terminal, a charging control unit outputs an alternating current signal having a charging control voltage based on a charging control signal. A power transmission unit excites a near-electromagnetic field. A primary-side signal processing unit acquires a reception signal on the basis of a voltage at the power transmission unit at the time of load modulation communication and sets the charging control signal on the basis of reference information included in the reception signal. In a power receiving terminal, a power receiving unit is couplable to the near-electromagnetic field excited by power transmission unit. A charging voltage generating unit generates a charging voltage for a rechargeable battery. A load modulation unit changes the load impedance of the power receiving unit as viewed from the power transmission unit by performing load modulation at the time of load modulation communication. A secondary-side signal processing circuit controls the load modulation unit at the time of load modulation communication using the acquired reference information.