Wireless Charging Bias Voltage Dynamic Switching
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Solution Overview
Problem
High power wireless charging systems face efficiency issues due to significant power losses caused by the voltage difference between the output voltage of the receiver rectifier and the receiver bias voltage, which affects performance across various input and output conditions.
Innovation Solution
A high efficiency wireless charging system is designed with a rectifier, a first stage, and a second stage connected in cascade, along with a bias voltage source that can be connected to different voltage potentials through switches, allowing for efficient power management and reduced power losses by adjusting the bias voltage source based on output voltage thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a high power wireless power transfer system is used, then the power transfer capability is improved, but the power loss increases due to voltage difference between rectifier output and bias voltage
Solution Approach 1:
The bias voltage source is made dynamically adjustable through switching between multiple voltage sources (first voltage source, second voltage source, third voltage source) based on the output voltage level. This dynamic adaptation allows the bias voltage to track the rectifier output voltage, minimizing voltage difference and power loss while maintaining high power transfer capability.
Solution Approach 2:
The system changes the voltage parameter of the bias voltage source by selecting different voltage sources according to the rectifier output voltage. When output voltage is high, a higher bias voltage is selected; when output voltage is low, a lower or zero bias voltage is selected. This parameter adaptation resolves the contradiction by optimizing the voltage difference under different operating conditions.
2Device complexity
If the bias voltage is kept constant, then the circuit design is simplified, but the efficiency decreases under varying load conditions
Solution Approach 1:
The bias voltage source transitions from a constant fixed value to a dynamically adjustable value that changes with load conditions. The controller switches between multiple voltage sources based on real-time output voltage detection, enabling the system to adapt to varying load conditions and maintain high efficiency without excessive complexity.
Solution Approach 2:
The bias voltage source is designed to serve multiple functions by incorporating multiple voltage sources that can be selectively activated. This multi-functional design allows the same circuit structure to handle different operating conditions (light load, heavy load, varying output voltage) efficiently, resolving the trade-off between simplicity and adaptability.
3Loss of energy
If multiple voltage sources are used for bias voltage, then the efficiency under varying conditions is improved, but the device complexity increases
Solution Approach 1:
The system uses dynamic switching control to select among multiple voltage sources based on real-time output voltage detection. This dynamic approach enables efficient power transfer under varying conditions while managing complexity through intelligent control rather than hardware complexity. The controller activates only the necessary voltage sources based on current operating conditions.
Solution Approach 2:
The system performs self-adjustment by automatically selecting the appropriate bias voltage source based on its own output voltage level. The controller monitors the rectifier output and autonomously switches between voltage sources without external intervention, enabling the system to optimize its own efficiency while managing complexity through self-regulation.
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 system achieves high efficiency in wireless charging by dynamically managing the bias voltage source, improving power transfer efficiency across different load conditions and reducing power losses, thereby enhancing overall system performance.
Implementation Method 1
A wireless power transfer system typically comprises a primary side transmitter and a secondary side receiver. The primary side transmitter is magnetically coupled to the secondary side receiver through a magnetic coupling.
Implementation Method 2
The primary side transmitter is magnetically coupled to the secondary side receiver through a magnetic coupling.
Data Source
AI summary
A system includes a receiver coil configured to be magnetically coupled to a transmitter coil, a rectifier connected to the receiver coil, a first stage and a second stage connected in cascade between the rectifier and a load and a bias voltage source configured to be connected with a first voltage node through a first switch and a second voltage node through a second switch, wherein one of the first voltage node and the second voltage node supplies power to the bias voltage source.