Wireless Charging Receive End Controller Impedance Adjustment
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Solution Overview
Problem
Existing wireless charging systems for electric vehicles face inefficiencies due to losses in controllable switching transistors, limiting the distance and speed of charging, and the lack of widespread charging station resources.
Innovation Solution
The system adjusts the reflection impedance at the receive end to enable zero voltage switching (ZVS) in the transmit end inverter, reducing power consumption and improving efficiency by matching the equivalent output impedance to a resistance inductivity, using a receive end controller to adjust the phase difference between the input current and bridge arm voltage based on target impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional wireless charging systems use controllable switching transistors in the inverter, then the system can perform wireless power transfer, but the switching transistors generate power losses that reduce operational efficiency
Solution Approach 1:
The patent applies parameter changes by adjusting the reflection impedance at the receive end to enable zero voltage switching (ZVS) in the transmit end inverter. By changing the impedance parameters and phase difference between input current and bridge arm voltage, the system achieves soft switching conditions that minimize switching losses in the controllable switching transistors, thereby reducing power loss and improving operational efficiency
2Productivity
If the inverter does not implement zero voltage switching, then the switching process is simpler, but power consumption increases and operational efficiency decreases
Solution Approach 1:
The patent implements feedback control through the receive end controller that adjusts the reflection impedance based on the target impedance sent by the transmit end controller. This closed-loop feedback mechanism enables the system to automatically achieve and maintain zero voltage switching conditions by continuously monitoring and adjusting the phase difference between input current and bridge arm voltage, thereby improving operational efficiency while managing control complexity through systematic feedback
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 adjustment enables the controllable switching transistor to implement ZVS, reducing power consumption and enhancing the operational efficiency of the wireless charging system, thereby improving charging speed and distance.
Implementation Method 1
the transmit coil Ct is configured to transmit the alternating current in a form of an alternating magnetic field
Implementation Method 2
A receive coil Cr of the receive end is configured to receive an alternating magnetic field and output an alternating current
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The present invention discloses a receive end and a transmit end of a wireless charging system, and a wireless charging system. The receive end includes a receive coil, a rectifier, and a receive end controller, where the receive coil receives an alternating magnetic field and outputs an alternating current; the rectifier is configured to rectify the alternating current from the receive coil into a direct current; the receive end controller is configured to adjust, based on a target impedance sent by a transmit end controller, a reflection impedance reflected from the receive end to a transmit end, so that an inverter of the transmit end implements zero voltage switching; and a bridge arm voltage is a voltage between two bridge arm midpoints of a full bridge rectifier or a voltage between a single bridge arm midpoint of a half bridge rectifier and ground. The reflection impedance reflected from the receive end to the transmit end is adjusted, to further adjust an equivalent output impedance of the inverter of the transmit end, so that a controllable switching transistor of the inverter implements zero voltage switching, and a reflection impedance required by the transmit end is used as the target impedance, so that the receive end adjusts an actual reflection impedance of the receive end based on the target impedance to meet a requirement of the transmit end.