Dual-loop Wireless Battery Charging System Voltage Ripple Control
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Solution Overview
Problem
Conventional wireless battery charging systems experience voltage ripples and interference with communication signals due to the shared inductive interface for power and communication, particularly during transitions between trickle and fast charging modes.
Innovation Solution
Implementing two separate charging regulators for trickle and fast charging modes, each controlling a distinct power FET with different current resolutions and ranges, to minimize voltage ripples and interference by using a digital control module to generate codewords for precise control of the charging currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single charging regulator controls the power FET for both trickle and fast charging modes, then the device complexity is reduced, but voltage ripples occur during mode transitions and communication interference increases
Solution Approach 1:
The patent divides the single charging regulator into two separate regulators: a first charging regulator for trickle charging mode and a second charging regulator for fast charging mode. Each regulator independently controls a power FET, allowing seamless mode transitions without voltage ripples that would interfere with communication signals.
2Productivity
If the charging current is rapidly switched between trickle and fast charging modes, then the charging speed is improved, but voltage ripples are generated that disrupt communication signals
Solution Approach 1:
The patent implements dynamic control by using a digital control module that generates codewords to switch between different charging modes based on battery state. The system can rapidly transition between trickle and fast charging modes while maintaining voltage stability through coordinated control of multiple regulators and power FETs.
3Device complexity
If the same inductive interface is used for both power transfer and communication, then the device complexity is reduced, but communication signals are interfered with during power switching
Solution Approach 1:
The patent segments the power control function into multiple independent regulators, each dedicated to specific charging modes. This segmentation allows precise control of power switching events, preventing voltage ripples from disrupting communication signals that share the same inductive interface.
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 solution reduces voltage ripples in the rectified DC voltage and minimizes interference with wireless communication, ensuring stable and efficient battery charging without disrupting communication signals.
Implementation Method 1
The TX and RX inductor coils 116 and 132 form an inductive interface 120 for wirelessly (i.e., magnetically) transferring power from the TX 110 to the RX 130
Data Source
AI summary
A wireless battery charging system includes a trickle power device (e.g., FET) that generates a trickle charging current for charging a battery and a trickle charging regulator that controls the trickle power device. A fast charging device generates a fast charging current for charging the battery, where the fast charging current is greater than the trickle charging current. A fast charging regulator controls the fast charging device. A digital control module generates a trickle charging codeword to control the trickle charging regulator and a fast charging codeword to control the fast charging regulator. Each charging regulator has a programmable current mirror that generates a mirrored current signal based on a codeword from the digital control module. The digital control module instructs the charging regulators to control the power devices to operate in a trickle charging mode, a fast charging mode, and transitions between those modes.