Transient Protection for Wireless Power Transfer Systems
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Solution Overview
Problem
Conventional wireless power transfer systems face challenges in providing a fast transient response due to inadequate feedback control, leading to over-voltage issues as power consumption increases and coupling or load conditions change.
Innovation Solution
A transient protection apparatus and method that includes a controller to detect current changes in the transmitter coil at one-fourth of the switching cycle, comparing it with predetermined thresholds to determine the type of transient occurring, and applying a control mechanism to the power converter to regulate output voltage effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional feedback control is used in wireless power transfer system, then the system structure remains simple, but the transient response becomes slow and cannot regulate output voltage effectively under coupling or load transients
Solution Approach 1:
The patent applies preliminary action by detecting the current at one-fourth of the switching cycle to predict transient conditions before they fully develop. This advance detection allows the control system to prepare and respond to coupling or load transients faster than conventional feedback control, improving transient response speed without requiring complex additional hardware
Solution Approach 2:
The patent implements an improved feedback mechanism that combines the one-fourth cycle current detection with traditional feedback control. By comparing the detected current with predetermined thresholds, the system generates appropriate feedback signals to regulate output voltage during transients, achieving both fast response and effective voltage regulation while maintaining reasonable system complexity
2Reliability
If over-voltage protection devices such as sink resistors and clamping capacitors are employed, then output voltage can be limited within predetermined range, but the transient response becomes slower and system efficiency decreases
Solution Approach 1:
The patent replaces passive over-voltage protection devices with an active feedback control mechanism that uses one-fourth cycle current detection. This feedback approach dynamically adjusts the power conversion device operating variables to prevent over-voltage conditions, providing both protection capability and maintained system efficiency by avoiding the continuous power loss associated with sink resistors and clamping capacitors
Solution Approach 2:
The patent changes the operational parameters of the power conversion device based on detected transient conditions. By adjusting operating variables such as duty cycle or switching frequency in response to current threshold comparisons, the system maintains reliable over-voltage protection while preserving high efficiency, unlike fixed passive protection devices that continuously reduce efficiency
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 enables a reliable and fast transient response, preventing over-voltage stress on the receiver by distinguishing between coupling and load transients and applying appropriate PID control mechanisms, thereby enhancing the system's operational stability and efficiency.
Implementation Method 1
A transmitter coil is configured to be magnetically couple to a receiver coil
Data Source
AI summary
A method includes in a switching cycle of a power converter in a wireless power transfer system, finding a time instant corresponding to one fourth of the switching cycle, wherein the power converter is coupled between an input power source and a transmitter coil magnetically coupled to a receiver coil, at the time instant, detecting a current flowing through the transmitter coil, wherein power transferred between the transmitter coil and the receiver coil is proportional to the current flowing through the transmitter coil, comparing the current flowing through the transmitter coil with a plurality of predetermined thresholds to determine whether a transient occurs, and applying a control mechanism to the power converter in response to an occurrence of the transient.