Battery Current Measurement Using Test Pattern Signal Verification
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Solution Overview
Problem
Current battery systems face challenges in cost-effectiveness and development effort due to the need for high ASIL levels in microcontrollers for current measurement, which is complex and costly, especially with the use of Hall sensors and shunt resistors, and are sensitive to magnetic fields, requiring additional shielding.
Innovation Solution
A method where a first microcontroller with a higher safety level generates and compares a test pattern signal with the current measurement signal, outsourcing these tasks from a second microcontroller with lower safety level, eliminating the need for additional hardware like Hall sensors and reducing wiring complexity, while ensuring ASIL C safety levels are met.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Hall sensors and shunt resistors are used for current measurement, then measurement precision is improved, but device complexity and cost increase due to additional shielding requirements
Solution Approach 1:
The patent extracts the current measurement function from the second microcontroller and relocates it to the first microcontroller. This eliminates the need for additional Hall sensors and shunt resistors, removing the associated magnetic shielding requirements while maintaining measurement precision through the existing current sensor integration
Solution Approach 2:
The first microcontroller is designed to perform multiple functions including both control operations and current measurement verification. By making the first microcontroller universal, the system eliminates dedicated current measurement hardware and reduces overall system complexity while maintaining ASIL C safety levels
2Measurement precision
If Hall sensors are used for current measurement, then measurement precision is improved, but manufacturing cost increases due to expensive components and shielding
Solution Approach 1:
The patent removes the need for expensive Hall sensors and associated magnetic shielding by extracting the current measurement function to the first microcontroller, which utilizes existing current sensor integrations already present in the battery management system, thereby significantly reducing component costs
Solution Approach 2:
The patent replaces expensive, sensitive Hall sensors with a software-based measurement verification approach using the first microcontroller. This substitution uses lower-cost existing system resources rather than expensive dedicated hardware, reducing manufacturing costs while maintaining measurement accuracy
3Device complexity
If current measurement tasks are performed by a microcontroller with lower safety level, then device complexity is reduced, but reliability decreases due to insufficient safety level
Solution Approach 1:
The first microcontroller acts as an intermediary that verifies the current measurement signal from the second microcontroller. It generates test pattern signals, compares them with actual measurement signals, and validates the integrity of current measurements, thereby ensuring ASIL C reliability without requiring the second microcontroller to have high safety level
Solution Approach 2:
The first microcontroller implements a feedback mechanism by generating test pattern signals and comparing them with actual current measurement signals. This closed-loop verification ensures measurement reliability and maintains ASIL C safety levels even when the primary measurement microcontroller has lower safety level
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 reduces implementation costs and development efforts, eliminates the need for magnetic shielding, and simplifies the system by using a microcontroller with lower safety levels for current measurement tasks, ensuring reliable and safe current verification without additional hardware or complexity.
Implementation Method 1
a shunt resistor 26 for measuring the electric current
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
An electric current measuring arrangement (1) and a corresponding method for a battery system with a first control unit (10) comprising a first microcontroller (12) and a second control unit (20) with a second microcontroller (22), an amplifier (24, 32) electrically interconnected between the second microcontroller (22) and terminals (T1, T2) of a shunt resistor (26) for current measurement, a node (N1, N2) interconnected between one of the terminals (T1, T2) of the shunt resistor (26) and the amplifier (24, 32) and a communication line (50) communicatively connecting the first control unit (10) and the second control unit (20). The first microcontroller (12) is configured to generate a test pattern signal (60) and transmit the test pattern signal (60) to the second control unit (20) through the communication line (50). The second control unit (20) is configured to transmit the test pattern signal (60) to the node (N1, N2). The second microcontroller (22) is configured to receive a measuring signal (64, 66) in response to the transmitted test pattern signal (60) through the amplifier (24, 32). The first microcontroller (12) is configured to receive the measuring signal through the communication line (50) from the second microcontroller (22), compare the measuring signal (64, 66) with the generated test pattern signal (60) and detect the functionality of the current measurement based on the comparison.