Current Sensor Offset Compensation Using Temperature Difference
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Solution Overview
Problem
Current sensor offset compensation abnormalities, such as noise and aging, lead to abnormal motor current control, increased fuel consumption, reduced drivability, and potential inverter damage, due to ineffective temperature-based offset determination methods.
Innovation Solution
A method for determining and re-compensating current sensor offset abnormalities by comparing power module estimation temperature with measured inverter temperature during vehicle stop and increased inverter temperature during driving, with a warning signal generated for frequent re-compensation needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If offset compensation is performed using average value of current sensor output, then offset compensation is achieved, but abnormal offset compensation occurs due to noise and disturbances
Solution Approach 1:
The patent changes the parameter used for offset compensation from current sensor output average value to temperature difference between power module estimation temperature and inverter measured temperature. This parameter change makes the offset compensation immune to electrical noise and disturbances while maintaining accuracy.
Solution Approach 2:
The patent introduces temperature difference as an intermediary parameter to determine offset compensation abnormalities. Instead of directly using current sensor output, the system uses temperature difference as a mediator to indirectly detect and compensate for offset abnormalities, eliminating the direct impact of noise on the compensation process.
2Ease of operation
If temperature-based offset determination is used, then offset compensation is simplified, but abnormal offset cannot be detected
Solution Approach 1:
The patent implements a feedback mechanism where the temperature difference is continuously monitored and used to determine both the offset compensation value and the abnormality status. The system feeds back the temperature difference information to the offset compensation unit, enabling both simplified operation and accurate abnormality detection through the same temperature-based parameter.
Solution Approach 2:
The patent uses temperature difference as the key parameter for both simplified offset determination and abnormality detection. By changing from current-based to temperature-based parameter, the system achieves both ease of operation and detection capability simultaneously.
3Productivity
If offset compensation abnormality is not detected, then system operation continues, but fuel consumption increases and drivability deteriorates
Solution Approach 1:
The patent uses feedback from temperature difference monitoring to detect offset compensation abnormalities in real-time. When an abnormality is detected through the temperature-based feedback mechanism, the system can take corrective actions to prevent increased fuel consumption and drivability deterioration, while maintaining continuous operation.
Solution Approach 2:
The patent converts the previously harmful effect of temperature difference (which was just a byproduct) into a beneficial detection mechanism. By utilizing the temperature difference that already exists in the system, the patent enables abnormality detection without adding significant complexity, turning a neutral or potentially harmful parameter into a useful diagnostic tool.
4Device complexity
If no additional hardware is added for detection, then system complexity is reduced, but offset abnormality detection capability is limited
Solution Approach 1:
The patent makes the existing temperature measurement system multi-functional. The temperature sensors and processing units that already exist in the motor driving system are used for both normal operation control and offset compensation abnormality detection. This universal use of existing hardware achieves detection capability without adding new components.
Solution Approach 2:
The system uses its own existing temperature measurement infrastructure to detect offset abnormalities, rather than requiring external or additional detection hardware. The motor driving system performs self-diagnosis using its built-in temperature sensing capability, eliminating the need for separate detection devices.
Data Source
AI summary
An offset compensation method of a current sensor is provided for determining whether an offset compensation of the current sensor is abnormal, and a motor driving system includes the current sensor. The offset compensation method includes: compensating for an offset of the current sensor, and determining whether the offset compensation of the current sensor is abnormal.