Non-Contact Power Inverter Control for Fast Coil Entry Detection
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Solution Overview
Problem
Existing non-contact power supply systems face challenges in high-speed detection of the entry and exit of a power receiving coil, leading to increased power loss and noise due to low failure tolerance in exit detection.
Innovation Solution
A power transmission device with an inverter and a controller that alternates between power transmission and coil detection modes, using a series unit of an inductor and capacitor, and a parallel unit of a second capacitor and power transmitting coil, to quickly determine the presence or absence of the power receiving coil based on input power parameters and state after mode transition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power transmitting side and power receiving side cooperate in sequence to detect coil entry and exit, then the detection can be performed with coordinated control, but the switching speed is limited and cannot achieve high-speed detection
Solution Approach 1:
The patent divides the detection function into independent segments: the power transmitting side performs detection independently using its own controller and circuit parameters, without waiting for coordination responses from the power receiving side. This segmentation enables the transmitting side to determine coil entry and exit based solely on its own operational parameters, achieving high-speed detection while maintaining reliable accuracy.
2Productivity
If the exit detection of the power receiving coil fails, then the system continues to operate, but current flows for a considerable time causing increased power loss and noise
Solution Approach 1:
The patent implements a feedback mechanism where the controller continuously monitors operational parameters (current, voltage, impedance) and automatically determines coil entry and exit states. When the coil is detected to have exited, the system provides feedback to stop current flow, preventing continued operation that would cause power loss and noise. This closed-loop feedback ensures energy efficiency while maintaining continuous operational capability.
3Power
If the inverter operates continuously at rated power, then maximum power transmission is achieved, but power loss increases when the power receiving coil is not present
Solution Approach 1:
The patent employs dynamic operation where the inverter's output power is adjusted based on real-time detection of coil presence. The controller dynamically switches between rated power operation (when coil is present) and reduced/zero power operation (when coil is absent or entering/exiting). This dynamic adjustment optimizes power transmission efficiency by matching output power to actual load conditions, reducing energy loss during transitions.
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
Enables high-speed detection of the power receiving coil's entry and exit, reducing power loss and noise by optimizing mode switching and current threshold settings.
Implementation Method 1
a power transmitting coil 5 to be magnetically coupled to an external power receiving coil 11 to transmit electric power to the power receiving coil
Data Source
AI summary
A series unit of an inductor and a first capacitor is connected to the AC side of the inverter, a series unit of a second capacitor and the power transmitting coil is connected in parallel to the first capacitor, a controller controls the inverter by switching between two modes that are a power transmission mode in which power is transmitted to the power transmitting coil and a coil detection mode in which a low output period and a zero output period are alternately repeated, and switching of the modes is performed on the basis of a state after mode transition in which information changes at a point in time when a predetermined condition is satisfied after mode switching, and a value of an operation parameter at least related to input power to the inverter.