Inductive Charging Field Feedback for EMC and Emission Control
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Solution Overview
Problem
Inductive energy transmission devices face efficiency losses and EMC interference due to unwanted energy emissions, leading to heating of metallic objects and violations of high-frequency regulations, which can result in equipment being taken out of service and incurring significant costs.
Innovation Solution
A method for operating a wireless energy transmission device that measures field strength between transmission and receiving coils to optimize working parameters, such as current, voltage, frequency, and modulation, using multiple measuring devices to reduce EMC interference and improve efficiency, while ensuring compliance with regulatory requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If inductive energy transmission is used to transmit electrical energy wirelessly, then energy can be transmitted without physical contact, but a portion of the transmitted energy is emitted into the surrounding space causing efficiency losses and undesirable effects
Solution Approach 1:
The patent employs measuring devices to detect the alternating magnetic field in the air gap between transmission and receiving coils. The control unit receives measurement results and adjusts the working point of the energy transmission device accordingly, creating a closed-loop feedback system that maximizes transmission efficiency while minimizing energy loss to the surrounding space
Solution Approach 2:
The control unit dynamically adjusts working parameters (such as frequency, voltage, or current) of the transmission coil based on measured field strength values. By changing these parameters in real-time, the system optimizes the coupling between coils and reduces unwanted energy emissions into the surrounding space
2Productivity
If high field strength is used to improve transmission efficiency, then energy transmission efficiency increases, but undesired emissions increase causing heating of metallic objects and EMC interference
Solution Approach 1:
Multiple measuring devices detect the alternating magnetic field strength in the air gap, providing real-time feedback to the control unit. This enables dynamic adjustment of transmission parameters to maintain optimal efficiency while preventing excessive field strength that would cause harmful emissions and EMC interference
Solution Approach 2:
The patent uses the measuring devices to detect not only the useful magnetic field for energy transmission but also the harmful emissions. By measuring the field strength, the system can identify when emissions become harmful and adjust parameters accordingly, converting the potential harm into useful information for optimization
3Measurement precision
If multiple measuring devices are used to detect field strength, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent divides the measurement task across multiple measuring devices positioned at different locations in the air gap. Each device measures local field strength, and the control unit processes these segmented measurements to determine the overall working point, improving measurement precision without requiring a single complex measurement system
Solution Approach 2:
The measuring devices serve multiple functions: they detect field strength for efficiency optimization, identify harmful emissions for EMC compliance, and provide data for dynamic working point adjustment. This multi-functionality justifies the added complexity by delivering multiple benefits from the same measurement infrastructure
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 method maximizes energy transmission efficiency, reduces unwanted emissions, and allows safe operation in EMC-sensitive environments, ensuring compliance with wireless communication regulations and preventing equipment shutdowns.
Implementation Method 1
the field strength of the alternating magnetic field in an air gap between the transmission coil and the receiving coil is measured
Implementation Method 2
a transmission coil, which is suitable for an inductive energy transmission
Data Source
AI summary
The invention relates to a method for operating a wireless energy transmission device (1), for example for charging an energy storage device (2) of an electric vehicle, comprising at least one transmission coil (4), which is suitable for an inductive energy transmission and which comprises a transmission coil control unit (5), and at least one receiving coil (6), which is suitable for an energy transmission and which comprises a receiving coil control unit (7). The wireless transmission device additionally comprises at least one first measuring element (8) and a first measuring device (9) which is connected to the measuring element, wherein in a first step, the field strength in an air gap (10) between the transmission coil (4) and the receiving coil (6) is measured by the at least one measuring device (9) using the measuring element (8), and, in a second step, the transmission coil control unit (5) sets the working point of the energy transmission while taking into consideration the field strength value measured by the measuring element (8) such that the degree of efficiency of the energy transmission device (1) is maximized.