Battery Cell Voltage Filter Circuit Using Standardized Components
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Solution Overview
Problem
In power supply devices with assembled batteries, the frequency response of filter circuits is difficult to equalize due to varying capacitor values, leading to inconsistent output signals when standardized capacitors are not available.
Innovation Solution
A power supply device with filter circuits containing (N+1) pieces of filter resistors of the same resistance value and (N+1) pieces of filter capacitors of the same capacitance, where one end of each capacitor is connected between the resistors and output terminals, and the other end is common, ensuring standardized circuit components and equalized frequency responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If different capacitance values are used to equalize frequency responses in filter circuits, then the frequency response accuracy is improved, but the device complexity and component variety increase
Solution Approach 1:
The patent changes the resistance values of resistors in different filter circuits while keeping capacitor values standardized, thereby adjusting the frequency response characteristics without requiring different capacitor types. This resolves the contradiction by maintaining measurement precision through parameter adjustment while avoiding increased device complexity
Solution Approach 2:
The patent applies different resistance values to specific resistors in specific filter circuits based on their position in the battery string, allowing each filter circuit to have customized frequency response characteristics while using the same standardized capacitor components throughout, thus improving accuracy without increasing component variety
2Measurement precision
If non-standardized capacitors are used to achieve optimal capacitance values, then the frequency response equalization is improved, but the ease of manufacture deteriorates
Solution Approach 1:
Instead of changing capacitor values to achieve optimal frequency responses, the patent changes the resistance values of resistors, which come in standardized E-series values. This allows frequency response equalization using readily available standardized components, improving ease of manufacture while maintaining measurement precision
Solution Approach 2:
The patent uses the same standardized capacitor model across all filter circuits, copying the same component throughout the system. Different frequency responses are achieved by varying resistor values rather than capacitor values, making the design easier to manufacture and maintain
3Adaptability or versatility
If filter circuits with different frequency responses are used, then the adaptability to different battery configurations is improved, but the measurement precision of voltage detection deteriorates
Solution Approach 1:
The patent applies different resistance values to resistors in filter circuits depending on their position in the battery string (e.g., different values for filters monitoring different battery cells). This local customization of resistance values allows each filter to be optimized for its specific position while maintaining consistent capacitor values, thereby achieving both adaptability and measurement precision
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 configuration allows for easy equalization of frequency responses in filter circuits using standardized components, reducing costs and preventing noise in digital signals by attenuating high-frequency components, thus improving voltage detection accuracy.
Implementation Method 1
a filter circuit that attenuates a specified frequency component of analog signals corresponding to terminal potentials of battery cells
Implementation Method 2
the types of standardized capacitors (general-purpose capacitor) are limited, compared with the resistors
Implementation Method 3
the accuracy of the voltage detection may decrease. Concretely, it is necessary that the maximum frequency of an analog signal inputted into the analog/digital converter does not exceed the half value (Nyquist frequency) of the sampling frequency
Data Source
AI summary
A power supply device includes: an assembled battery that is configured of N pieces of battery cells connected in series; (N+1) pieces of measurement lines that obtain analog signals corresponding to terminal potentials of the battery cells; a filter circuit that attenuates a specified frequency component of the inputted analog signals and outputs; and an analog/digital converter that converts the analog signals outputted from the filter circuit into digital signals. The filter circuit is configured of: (N+1) pieces of input terminals; (N+1) pieces of output terminals; (N+1) pieces of filter resistors; and (N+1) pieces of filter capacitors of which one ends respectively connected between the filter resistors and the output terminals and the other ends are connected to each other in common.