Mains Charging Device Input Filter Adaptation
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Solution Overview
Problem
Mains-operated charging devices face challenges in operating efficiently with non-sinusoidal voltage profiles, which can lead to harmonic distortions and damage due to fast switching edges, especially when using inverters that output modified sine waves, causing excessive loading on input filters.
Innovation Solution
A charging device with a detection unit that analyzes the mains voltage for deviations from sinusoidality, using Fourier analysis or peak voltage evaluation, and automatically switches between different filter stages or connects a series resistor to adapt to sinusoidal or non-sinusoidal voltages, reducing inrush currents and filter loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the charging device uses a fixed input filter configuration designed for sinusoidal voltages, then it operates efficiently on sinusoidal mains voltage, but it experiences excessive loading and potential damage when connected to non-sinusoidal mains voltage with fast switching edges
Solution Approach 1:
The patent applies dynamics by making the input filter configuration adjustable rather than fixed. The control unit dynamically switches between different filter stages (first and second filter stages) depending on whether sinusoidal or non-sinusoidal mains voltage is detected. This dynamic adaptation allows the filter impedance to match the voltage characteristics, preventing excessive loading on non-sinusoidal voltages while maintaining efficiency on sinusoidal voltages.
Solution Approach 2:
The patent changes the electrical parameters of the input filter by switching between different filter configurations. When non-sinusoidal voltage is detected, the system changes the filter stage to one with appropriate impedance characteristics, thereby changing the filter's electrical parameters to suit the non-sinusoidal voltage profile and reduce harmful loading effects.
2Adaptability or versatility
If the charging device uses a single filter stage optimized for sinusoidal voltage, then the device complexity is low, but the adaptability to different voltage profiles is insufficient
Solution Approach 1:
The patent segments the input filter into multiple independent filter stages (first filter stage and second filter stage), each optimized for different voltage characteristics. The control unit selectively activates the appropriate stage based on voltage detection, enabling adaptability to both sinusoidal and non-sinusoidal profiles while managing complexity through modular segmentation.
Solution Approach 2:
The input filter unit is designed with multi-functionality by incorporating multiple filter stages that can be selectively activated. This universal design allows the same filter unit to handle both sinusoidal and non-sinusoidal voltage profiles effectively, making the charging device versatile across different voltage conditions without requiring entirely separate filter systems.
3Measurement precision
If the charging device continuously monitors mains voltage for sinusoidality detection, then the voltage profile accuracy is high, but the energy consumption and processing load increase
Solution Approach 1:
The patent implements feedback by continuously monitoring the mains voltage profile and using the detection results to control filter stage selection. The control unit receives feedback about voltage sinusoidality and adjusts the filter configuration accordingly, ensuring high measurement precision is translated into actionable control decisions that optimize both accuracy and resource usage.
Data Source
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AI summary
The invention relates to a method for operating a mains-operated charging device (10a; 10b) on a voltage supply mains having a mains voltage (12a; 12b) which, at least at times, can have a non-sinusoidal voltage curve (14a; 14b). According to the invention, in at least one method step, a deviation of the mains voltage (12a; 12b) from a sinusoidal form is detected.