Resonance Non-Contact Power Supply Impedance Matching
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Solution Overview
Problem
Resonance type non-contact power supply systems face inefficiencies in electric power transmission due to varying distances and impedance changes between the power supply and reception sides, particularly when charging batteries, as the load's impedance changes with the charging state, leading to increased reflected power and reduced efficiency.
Innovation Solution
The system adjusts the secondary matching unit before the primary matching unit, starting with a low AC power source output and gradually increasing it in multiple steps to minimize power loss during adjustment, ensuring efficient power transmission from the primary to the secondary side by matching the impedance of both units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the distance between resonance coils varies or impedance changes in the load, then the input impedance of the resonance system changes, but matching between the AC power source and the input impedance deteriorates, increasing reflected electric power
Solution Approach 1:
The patent applies dynamics by making the matching units variable rather than fixed. The primary matching unit (comprising variable capacitor C1 and variable inductor L1) and secondary matching unit (comprising variable capacitor C2 and variable inductor L2) can dynamically adjust their impedance values to match changing load conditions and distances, thereby maintaining efficient power transfer across varying operating conditions
Solution Approach 2:
The patent changes impedance parameters of the matching units to adapt to varying conditions. By adjusting the capacitance of variable capacitors C1 and C2, and the inductance of variable inductors L1 and L2, the system modifies its electrical parameters to maintain resonance and matching despite changes in distance or load impedance
2Adaptability or versatility
If the load varies with charging state of the battery, then the input impedance of the resonance system changes, but matching between the AC power source and the resonance system deteriorates, increasing reflected electric power
Solution Approach 1:
The matching units are designed as dynamic components that can adjust their impedance in real-time. The primary matching unit (variable capacitor C1 and variable inductor L1) and secondary matching unit (variable capacitor C2 and variable inductor L2) continuously adapt to load variations during battery charging, maintaining optimal matching conditions despite changing charging states
Solution Approach 2:
The system employs feedback control where the controller monitors the charging state and load conditions, then adjusts the matching units accordingly. This feedback mechanism ensures that the matching units respond to load variations and maintain efficient power transfer throughout the charging process
3Speed
If the AC power source output is increased before matching is accomplished, then power transmission speed increases, but power transmission efficiency deteriorates due to increased reflected electric power
Solution Approach 1:
The patent applies preliminary action by performing impedance matching adjustments before increasing the AC power source output. The controller first adjusts the primary matching unit (variable capacitor C1 and variable inductor L1) and secondary matching unit (variable capacitor C2 and variable inductor L2) to achieve proper matching, then increases power transmission. This preliminary matching prevents excessive reflected power during the adjustment phase
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 allows for efficient electric power transmission from the primary to the secondary side by synchronizing the impedance of both matching units, reducing reflected power and enhancing charging efficiency in non-contact power supply systems.
Implementation Method 1
a primary coil device (13) having a primary coil (13a) and a primary-side resonance coil (13b), and a secondary coil device (21) having a secondary-side resonance coil (21b) and a secondary coil (21a), wherein the primary coil (13a) is connected to the high-frequency power source (11) through the primary matching unit (12), and the secondary coil device (21) is arranged to receive the electric power from the primary coil device (13)
Implementation Method 2
the output frequency of the AC power source, which is the resonance frequency of the resonance system
Data Source
Figure 1
AI summary
Power supply equipment (10) is provided with an AC power supply (11) and a primary-side resonance coil (13b). Movable body equipment (20) is provided with a secondary-side resonance coil (21 b), which receives power from the primary-side coil, a rectifier (23), which rectifies the received power, a charger (24) to which the rectified power is supplied, and a secondary battery (25), which is connected to the charger. A primary matching unit (12) is provided between the AC power supply (11) and the primary-side resonance coil (13b). A secondary matching unit (22) is provided between the secondary-side resonance coil (21 b) and the rectifier (23). A control unit is provided to either the power supply equipment (10) or the movable body equipment (20). The control unit controls a primary matching unit adjustment unit (14) and a secondary matching unit adjustment unit (26). In order to efficiently transfer power from the primary side to the secondary side when charging the secondary battery, the control unit initially adjusts the secondary matching unit (22). After adjusting the secondary matching unit (22), the control unit adjusts the first matching unit (12).