Active Rectifier Current Feedback for Wireless Power Transfer
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Solution Overview
Problem
Wireless power systems face inefficiencies in charging and heating high-voltage batteries due to limitations in active rectification, particularly in managing input currents and power transmission efficiently.
Innovation Solution
The method involves determining a reference value for the current in the active rectifier based on load requirements, transmitting signals to adjust the input current, and using PWM signals to drive transistors when the new current value is within a predetermined range, along with capacitive snubbers to reduce reactive current and switching losses, ensuring efficient power delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If active rectification is used in wireless power receivers, then power transmission efficiency is improved, but managing input currents and reducing switching losses becomes more challenging
Solution Approach 1:
The patent implements a feedback control mechanism where the controller continuously monitors the input current to the active rectifier and compares it against a reference value. Based on this comparison, the controller dynamically adjusts the switching signals to the transistors, creating a closed-loop system that automatically maintains optimal current levels without requiring complex manual intervention or oversight.
Solution Approach 2:
The active rectifier system performs self-regulation of its input current through the feedback mechanism. The controller autonomously determines when the input current exceeds the reference value and automatically generates appropriate PWM signals to adjust transistor switching, enabling the system to manage its own current without external control intervention.
2Power
If input current is increased to meet load requirements, then power delivery is improved, but reactive current increases
Solution Approach 1:
The feedback control mechanism monitors not only the magnitude of the input current but also its characteristics. When reactive current components cause the input current to exceed the reference value, the controller adjusts the switching signals to correct the current waveform, thereby maintaining power delivery while suppressing reactive current components.
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 approach enhances the efficiency of wireless power systems by allowing precise control of power transmission, reducing reactive current, and increasing output power while maintaining low switching losses, enabling effective charging and heating of high-voltage batteries.
Implementation Method 1
capacitive snubbers to reduce reactive current and switching losses
Implementation Method 2
capacitive snubbers to reduce reactive current and switching losses
Implementation Method 3
driving at least one transistor in the rectifier with a PWM signal
Implementation Method 4
transmitting, to a wireless power transmitter, a signal representative of the required value change
Data Source
AI summary
Disclosed herein are methods and systems for controlling an active rectifier of a wireless power receiver. The exemplary methods can include determining a reference value of a current into the rectifier, the reference value being based on a load requirement; determining a required value change in a present input current into the rectifier based on the reference value; transmitting, to a wireless power transmitter, a signal representative of the required value change in the present input current; determining a new value of the present input current after transmitting the signal; and, when the new value is within a predetermined range of the required value change, driving at least one transistor in the rectifier with a PWM signal based on the new value.