Battery Pack Voltage Measurement Using Resistance Ratio Calibration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing high voltage battery pack measurement systems face challenges in achieving accurate and stable voltage measurements due to the instability and drift of components over time, leading to increased costs and potential safety issues.
Innovation Solution
The proposed system and method involve generating reference voltages associated with high voltage direct current input signals, measuring these voltages for a predetermined number of iterations, and calculating resistance ratios to determine the actual high voltage levels, thereby mitigating the effects of component instability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional voltage measurement systems use stable and matched resistors to achieve accurate measurements, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent changes the measurement parameter from absolute voltage measurement to resistance ratio measurement. By measuring the ratio of resistances (R1/R2) instead of absolute voltage values, the system eliminates the need for highly stable and matched resistors, as ratio measurements are inherently less sensitive to component drift and environmental factors.
Solution Approach 2:
The patent uses a digital copy of the resistance ratio value stored in memory during power-up or wake-up periods. This digital representation allows the system to reference the calibrated ratio without requiring the physical resistors to maintain their exact original values, thereby reducing the stability requirements of the physical components.
2Reliability
If traditional systems use highly stable and matched resistors to reduce component drift, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive, highly stable resistors with standard, lower-cost resistors. The system compensates for the lower stability of these cheaper components by performing measurements during power-up or wake-up periods when the system is in a controlled state, and by using ratio measurements that cancel out drift effects.
Solution Approach 2:
The patent performs resistance ratio measurements during power-up or wake-up periods before normal operation begins. This preliminary measurement establishes a baseline ratio that is stored in memory, allowing the system to operate reliably during normal conditions without requiring the resistors to maintain extreme stability throughout operation.
3Measurement precision
If measurements are taken continuously to account for component drift, then measurement precision is maintained, but energy consumption increases
Solution Approach 1:
The patent performs resistance ratio measurements periodically during power-up or wake-up events rather than continuously during operation. This periodic measurement approach maintains measurement precision by recalibrating at appropriate intervals while significantly reducing energy consumption compared to continuous measurement.
Data Source
AI summary
An apparatus includes a first analog-to-digital converter configured to measure a first reference voltage and a third reference voltage. The apparatus also includes a second analog-to-digital converter configured to measure a second reference voltage and a fourth reference voltage. The apparatus also includes a controller configured to calculate a first resistance ratio, and determine a positive high voltage associated with the positive high voltage direct current input signal based, at least in part, on the first resistance ratio. The controller is further configured to calculate a second resistance ratio, and determine a negative high voltage associated with the negative high voltage direct current input signal based, at least in part, on the second resistance ratio.