Synchronous Rectifier Shunting in Wireless Power Safety Circuits
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Solution Overview
Problem
High-power wireless charging systems pose safety hazards due to high currents and voltages, necessitating effective safety circuits to prevent electrical shocks during charging, especially in applications like electric vehicles.
Innovation Solution
The implementation of a magnetic inductive resonance charging circuit with a resonant network, synchronous rectifier, and shunting mechanisms that include balanced capacitors, normally open and closed switches, and sensors to monitor and control the AC and DC signals, ensuring safe power transfer by shunting power in fault conditions and mitigating electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-power wireless charging is implemented to achieve faster charging, then charging speed is improved, but safety hazards from high current and voltage increase
Solution Approach 1:
The patent implements preliminary safety actions by incorporating fault detection circuits and shunt switches that are pre-configured to activate before dangerous fault conditions can develop. The system continuously monitors for abnormal conditions and is ready to shunt power immediately upon detecting a fault, preventing electrical shock hazards from materializing while maintaining high-power charging operation.
Solution Approach 2:
The patent introduces intermediary safety components including shunt switches and fault detection circuits that act as mediators between the high-power wireless charging system and the user. These intermediaries detect fault conditions and intervene by shunting power away from potentially hazardous paths, thereby protecting users from electrical shock while allowing the high-power charging to continue operating under safe conditions.
2Reliability
If shunting mechanisms are added to improve safety, then safety is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by implementing shunt switches and fault detection only at critical points in the circuit where safety is most needed, rather than throughout the entire system. The shunt switches are strategically placed to shunt power only during fault conditions, and the fault detection circuits monitor specific parameters, thereby providing comprehensive safety coverage while minimizing the overall complexity of the circuit architecture.
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 enhances safety by preventing electrical shocks during high-power wireless charging, ensuring reliable and efficient power transfer while minimizing the risk of faults and electromagnetic interference, particularly in electric vehicle charging applications.
Implementation Method 1
a resonant network comprising an inductive secondary coil that converts a magnetic field received from an inductive primary coil into an alternating current (AC) signal
Implementation Method 2
a synchronous rectifier that rectifies the AC signal to generate a direct current (DC) signal for application to a load to be charged
Implementation Method 3
The resonant network includes first and second balanced capacitors connected in series to respective ends of the secondary coil whereby the AC signal series resonates with the first and second capacitors
Data Source
AI summary
A magnetic inductive resonance charging circuit includes a resonant network having an inductive secondary coil that converts a magnetic field received from an inductive primary coil into an alternating current (AC) signal and a synchronous rectifier that rectifies the AC signal to generate a direct current (DC) signal for application to a load. The synchronous rectifier includes a variety of configurations for shunting the AC waveform of an AC current source in the event of a fault. For example, a rectifier controller may hold a pair of normally open switches of the rectifier off and a pair of normally closed switches of the rectifier on to shunt the AC current source when an over-voltage, over-current fault condition or an over-temperature fault condition is detected. Configurations are provided for grounding the capacitive electromagnetic interference produced in the chassis of an electric vehicle when the resonant network is unbalanced.