Wireless Power Transmission Coil Current Control
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Solution Overview
Problem
Existing wireless power supply systems face challenges in accurately transmitting power due to sudden changes in relative impedance between the power transmission and receiving coils, leading to excess or deficiency in power transmission, especially during changes in the gap between the coils.
Innovation Solution
A wireless power supply system with a power transmission device and a power receiving device that utilize two communication loops: a first loop for stabilizing power supply based on battery state of charge and a second loop with a shorter sampling cycle to adjust voltage and current, ensuring accurate power transmission by continuously monitoring and adjusting output voltage and current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wireless communication between power transmission device and power receiving device is performed in a long cycle to stabilize communication, then communication stability is improved, but power transmission accuracy deteriorates due to inability to respond to sudden impedance changes
Solution Approach 1:
The patent segments the control loop into two distinct cycles: a long communication cycle for stable data exchange and a short detection cycle for rapid impedance monitoring. This segmentation allows each cycle to serve its specific function optimally without interfering with the other, resolving the contradiction between communication stability and power transmission accuracy.
Solution Approach 2:
The system employs periodic actions with different frequencies: long-cycle communication for stability and short-cycle detection for responsiveness. By using multiple periodic actions with different periods, the system achieves both communication reliability and accurate power transmission control.
2Reliability
If long-cycle communication is used to stabilize communication between devices, then communication reliability is improved, but response speed to situational changes deteriorates
Solution Approach 1:
The control system is segmented into communication functions (long cycle) and detection/control functions (short cycle). This segmentation enables the system to maintain reliable communication while simultaneously responding quickly to impedance changes through the separate short-cycle detection mechanism.
Solution Approach 2:
The system dynamically adjusts its operation by using two different time scales: long cycles for communication and short cycles for detection. This dynamic approach allows the system to be reliable when communicating and fast when detecting, adapting to different operational requirements.
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 effectively maintains constant power transmission levels, even with sudden changes in relative impedance, preventing overcharging and ensuring reliable battery charging, while also handling communication faults and variations in battery state of charge.
Implementation Method 1
a power transmission coil provided in a power transmission device on the ground side and a power receiving coil provided in a power receiving device mounted on a vehicle and facing the power transmission coil so as to supply electric power from the power transmission coil to the power receiving coil via a wireless connection
Data Source
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AI summary
A wireless power supply system includes a power transmission device (10) provided on a ground side and a power receiving device (20) mounted on a vehicle, the power transmission device (10) transmitting, to the power receiving device (20) via a wireless connection, electric power controlled by an inverter circuit (12), wherein the power receiving device (20) transmits a power supply command signal to the power transmission device (10) in a first cycle by use of a radio signal. The power transmission device (10) includes a power transmission coil current detection means for detecting a power transmission coil current flowing through a power transmission coil (13) and controls an output voltage of the inverter circuit (12) based on the power supply command signal and the power transmission coil current detected by the power transmission coil current detection means in a second cycle shorter than the first cycle.