Wireless Energy Transmitter Hysteresis Foreign Object Detection
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Solution Overview
Problem
Existing wireless energy transmission systems face reliability issues due to foreign objects interfering with the electromagnetic field, causing heating and energy disruption, which can lead to operational failures and safety risks.
Innovation Solution
The method employs a hysteresis-based foreign object detection system with multiple hysteresis regions to determine when to initiate or suspend energy transmission, using resonant frequency and quality factors, and adjusts based on operating modes and energy transmission parameters to optimize detection accuracy and reduce unnecessary interruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If foreign object detection is performed frequently to improve safety, then reliability improves, but productivity deteriorates due to increased interruptions in energy transmission
Solution Approach 1:
The patent applies dynamics by making the foreign object detection frequency adaptive rather than static. The control unit dynamically adjusts the detection interval based on operating conditions: during startup and mode changes, detections are performed frequently; during stable operation, the interval is extended. This dynamic adjustment resolves the contradiction by maintaining high safety during critical transitions while improving productivity during stable operation.
Solution Approach 2:
The patent changes the parameter of detection frequency based on operating modes. Different detection intervals are applied depending on whether the system is in startup mode, energy transmission mode, or standby mode. This parameter change allows the system to optimize between safety and productivity by matching detection intensity to operational context.
2Reliability
If foreign object detection is performed continuously to improve reliability, then safety improves, but loss of time increases due to extended detection cycles
Solution Approach 1:
The patent implements periodic action by performing foreign object detections at specific intervals rather than continuously. Detection cycles are triggered at defined events (startup, mode changes) and repeated at configured intervals during stable operation. This periodic approach maintains detection accuracy when needed while minimizing time loss during normal operation.
Solution Approach 2:
The patent applies preliminary action by performing foreign object detections in advance at critical transition points before energy transmission begins or changes mode. This preliminary detection ensures safety is verified before potentially harmful operations commence, reducing the need for continuous monitoring during stable operation.
3Productivity
If the quality factor threshold is set low to improve productivity, then energy transmission efficiency improves, but reliability deteriorates due to reduced detection sensitivity
Solution Approach 1:
The patent applies dynamics by making the quality factor threshold adaptive rather than fixed. The control unit dynamically adjusts the threshold based on the detected resonant frequency and operating conditions. This allows the system to maintain high detection sensitivity when foreign objects are likely present while permitting efficient energy transmission during normal operation.
Solution Approach 2:
The patent applies local quality by setting different quality factor thresholds for different operating modes and frequency ranges. Rather than using a single global threshold, the system applies localized threshold values appropriate to each operational context, enabling both high sensitivity and high efficiency in different situations.
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 enhances the reliability and efficiency of wireless energy transmission by minimizing false positives and negatives in foreign object detection, reducing cycle times, and ensuring safer operations by accurately determining the presence of foreign objects, thereby preventing damage and maintaining consistent energy transfer.
Implementation Method 1
the wireless energy transmission takes place by means of an electromagnetic field from a primary-side energy supply device to a secondary-side consumer
Implementation Method 2
a resonant transformer of the inductive charging device generating an alternating electromagnetic field with a charging coil
Implementation Method 3
a resonant transformer of the inductive charging device generating an alternating electromagnetic field with a charging coil
Implementation Method 4
if an electrically conductive foreign object comes within the range of the electromagnetic field of the coils, eddy currents can form that heat up the foreign object
Implementation Method 5
eddy currents can form that heat up the foreign object
Implementation Method 6
If the foreign object can be magnetized, it can also be heated up by hysteresis or remagnetization losses
Data Source
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AI summary
The invention relates to a method for wirelessly transmitting energy, in particular in an inductive manner, from an energy transmitting device (14) to a load (18). In at least one method step (46, 50), at least one resonance frequency (fres) and an actual quality (Qact,n+1(fres)) of the wireless energy transmission are detected, and in at least one other method step (54), a decision is made to interrupt the energy transmission from the energy transmitting device (14) to the load (18) in order to detect a foreign object. According to the invention, the decision to carry out the foreign object detection is based on a hysteresis (72) for the limits of the resonance frequency (fres) and the actual quality (Qact,n+1(fres)). The invention further relates to a wireless energy transmitting device (14) for carrying out the method according to the invention.