Current Measurement Verification via Test Current Superposition
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Solution Overview
Problem
Current methods for checking electrical current measurements in high-demand battery systems, such as those in electric vehicles, often require redundant designs and additional sensors, increasing costs and complexity.
Innovation Solution
A method and circuit that superimpose a known test current on the measured current to verify accurate measurement by comparing the resulting current, eliminating the need for redundant sensors and simplifying the measurement process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant current sensors are used to verify current measurements, then measurement reliability is improved, but device complexity and cost increase
Solution Approach 1:
The current measurement system performs self-verification by injecting a test current and comparing the measured change against the known test current value. This self-service mechanism eliminates the need for redundant sensors while maintaining measurement reliability through internal consistency checks.
Solution Approach 2:
The system changes the current parameter by superimposing a known test current on the measured current. By monitoring the change in current measurement when the test current is applied, the system can verify measurement accuracy without requiring additional sensors, thus resolving the contradiction between reliability and complexity.
2Measurement precision
If additional test equipment is added to verify current measurements, then measurement accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The verification system uses existing circuit components (current sensor, switching device, evaluation unit) to perform self-testing. By utilizing already-present hardware for verification purposes, the system achieves measurement accuracy improvement without additional manufacturing costs for separate test equipment.
Solution Approach 2:
The current sensor and evaluation unit serve dual functions: normal current measurement and verification testing. The switching device integrates both test current injection and normal circuit operation control. This multi-functionality eliminates the need for dedicated test equipment, reducing manufacturing costs while maintaining measurement precision.
3Reliability
If redundant measurement systems are implemented, then safety is improved, but system complexity increases
Solution Approach 1:
The system implements safety through self-verification rather than redundant parallel systems. The evaluation unit continuously monitors current measurements and detects inconsistencies by comparing expected versus actual current changes during test current injection, providing safety without the complexity of multiple independent measurement chains.
Solution Approach 2:
The system uses feedback from the current sensor during test current injection to verify measurement accuracy. The evaluation unit processes the feedback signal and determines whether the current measurement system is functioning correctly, enabling safety verification through a single integrated feedback loop rather than multiple independent systems.
Data Source
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AI summary
A method for checking an electrical current measurement is described. Said method comprises a first step of measuring a current to be measured IM using a current-measuring means (18). The method also comprises a second step of superimposing a test current IP on the current to be measured IM to form a resultant current IRes=IM+IP. This resultant current IRes is measured in a third step using the current-measuring means (18) within the period of time of the second step. In a fourth step, a check follows in order to determine whether the resultant current IRes measured in the third step corresponds to the sum of the current IM measured in the first step plus the known magnitude of the test current IP superimposed in the second step. An electrical circuit for carrying out the method according to the invention, a battery comprising the electrical circuit and a motor vehicle comprising the battery are also proposed.