Zero-crossing Current Detection for Dynamic Wireless Power Transfer
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Solution Overview
Problem
Synchronous wireless power transfer systems with active inverters face instability due to complex synchronization requirements, making them difficult to control, especially in dynamic environments without external hardware for detection and communication.
Innovation Solution
A synchronous inverter system with a primary inverter and controller that detects zero-crossing currents using a reactive component network and switching enable circuit, enabling robust and modular dynamic wireless power transfer by controlling switches based on current polarity and thresholds, eliminating the need for external synchronization or communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If synchronous WPT systems with active inverters are used, then wireless power transfer capability is achieved, but system stability deteriorates due to complex synchronization requirements
Solution Approach 1:
The system uses the existing primary current signal to generate synchronization information without requiring external communication hardware or complex synchronization protocols. The zero-crossing detection of the primary current automatically provides the timing reference needed for synchronous operation, making the system self-synchronizing and eliminating the instability caused by complex synchronization requirements.
Solution Approach 2:
The patent introduces a zero-crossing detection mechanism as an intermediary between the primary and secondary inverters. This intermediary extracts synchronization information from the primary current waveform and uses it to control the switching of the secondary inverter, thereby achieving stable synchronous operation without direct communication between the inverters.
2Measurement precision
If external hardware for detection and communication is added, then synchronization accuracy is improved, but device complexity increases
Solution Approach 1:
The system utilizes the primary current signal that already exists in the WPT system to provide synchronization information. No additional sensors, communication modules, or external detection hardware are required. The zero-crossing points of the primary current serve as natural synchronization markers, eliminating the need for complex external hardware while maintaining synchronization accuracy.
Solution Approach 2:
The primary current signal serves multiple functions: it carries power transfer information and simultaneously provides synchronization timing information through its zero-crossing points. This multi-functionality eliminates the need for separate detection and communication hardware, reducing system complexity while maintaining synchronization capability.
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 provides stable and efficient wireless power transfer to moving vehicles, ensuring robustness and autonomy in dynamic conditions without additional hardware, maintaining unity power factor and minimizing power losses.
Implementation Method 1
The primary pad wirelessly transmits power to a synchronous secondary inverter
Data Source
AI summary
An inverter for wireless power transfer includes a primary inverter connected in series with a first primary inductor. A first primary capacitor is connected in parallel with the first primary inductor and primary inverter. A series-connected second primary capacitor and primary pad inductor are in parallel with the second primary capacitor. The synchronous inverter includes a controller configured to detect a first primary current in the first primary inductor to control switches in the primary inverter to provide a positive primary inverter voltage across the output of the primary inverter in response to detecting a positive first primary current, and control the switches in the primary inverter to provide a negative primary inverter voltage across the output of the primary inverter in response to detecting a negative first primary current.