Wireless Power Receiver Input Voltage Feedback Control
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Solution Overview
Problem
In wireless power transmission systems, the presence of a filter circuit at the front stage of the load complicates feedback control due to voltage delays and drops, leading to instability and inefficiency in power control.
Innovation Solution
A wireless power receiving device with an input voltage detection circuit, an output voltage detection circuit, and a target voltage generation circuit that calculates a second target voltage based on the output voltage to adjust the input voltage, allowing for effective feedback control by transmitting difference information to the transmitting device, thereby stabilizing power delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If feedback control is performed using the output voltage of the filter circuit, then feedback control can be implemented, but feedback speed decreases due to delay in the filter circuit, making it difficult to secure stability of power control
Solution Approach 1:
The invention uses the input voltage to the filter circuit (which is obtained earlier in the signal path) as the feedback parameter instead of the output voltage. This preliminary action allows feedback control to be performed before the voltage passes through the filter circuit, avoiding the delay introduced by the filter and maintaining fast feedback speed while still achieving stable power control.
2Speed
If the input voltage to the filter circuit is fed to the wireless power transmitting device side for feedback control, then feedback speed is maintained, but voltage to be applied to the load falls due to voltage drop in the filter circuit
Solution Approach 1:
The invention changes the feedback parameter from output voltage to input voltage of the filter circuit. By using the input voltage (which has not yet undergone the voltage drop in the filter circuit) as the feedback parameter, the system maintains fast feedback speed while the wireless power transmitting device can compensate for the expected voltage drop, ensuring stable voltage at the load.
3Reliability
If a filter circuit is provided at the front stage of the load, then ripple voltage is reduced, but feedback control becomes difficult due to delay and voltage drop in the filter circuit
Solution Approach 1:
The invention performs feedback control using the input voltage to the filter circuit before the voltage passes through the filter. This preliminary feedback action allows the system to maintain effective control while the filter circuit continues to perform its function of reducing ripple voltage, thus resolving the contradiction between voltage stability and feedback control performance.
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 stable and efficient feedback control even when a filter circuit is present at the front stage of the load, ensuring the output voltage converges to its target value without voltage drops, thus improving power transmission stability and efficiency.
Implementation Method 1
a receiving coil that receives AC power through an AC magnetic field
Data Source
AI summary
A wireless power receiving device includes a receiving coil that receives AC power through an AC magnetic field, a rectification circuit that converts the AC power received by the receiving coil into DC power and outputs the obtained DC power to a load, a filter circuit provided between the rectification circuit and the load, an input voltage detection circuit that detects the input voltage of the filter circuit, an output voltage detection circuit that detects the output voltage of the filter circuit, a target voltage generation circuit that generates a second target voltage that is a target value of the input voltage based on the output voltage and a first target voltage that is a target value of the output voltage, and a receiving-side transmitter that transmits difference information indicating the difference between the input voltage and the second target voltage to the wireless power transmitting device.