Inverter Control Device for Current Sensor Diagnosis
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Solution Overview
Problem
The existing system for diagnosing battery current sensors in power conversion devices for hybrid and electric vehicles faces challenges in immediate detection after changes in current or torque commands, leading to potential abnormality misdetection due to deviations between PDU and battery current values.
Innovation Solution
An inverter control device calculates an estimated direct current value based on duty values and alternating current sensor values, allowing for continuous and reliable diagnosis of direct current sensors by comparing it with the actual direct current sensor values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the diagnosis is performed immediately after the current command value or voltage command value is changed, then the response speed of the diagnostic system is improved, but the measurement precision deteriorates due to temporal deviation between PDU current and battery current
Solution Approach 1:
The system performs preliminary actions by calculating both the PDU current (from command values) and battery current (from sensor) continuously and compares them in real-time. This preliminary continuous monitoring ensures that when a diagnosis is needed, the comparison data is already available, achieving both fast response and accurate measurement without waiting for current changes to complete.
2Measurement precision
If the diagnosis is delayed until after current changes complete, then the measurement precision is improved, but the productivity of the diagnostic system deteriorates
Solution Approach 1:
The diagnostic system maintains continuous operation by continuously calculating PDU current from command values and continuously measuring battery current from the sensor. This continuous useful action allows the system to provide immediate diagnostic results at any time without waiting for current changes to complete, thereby maintaining both high precision and high productivity simultaneously.
3Productivity
If real-time comparison is implemented, then the productivity of the diagnostic system is improved, but the reliability deteriorates due to abnormality misdetection
Solution Approach 1:
The system implements feedback by continuously comparing the calculated PDU current with the measured battery current and using this comparison to detect abnormalities. The feedback mechanism allows the system to maintain high productivity through continuous monitoring while ensuring high reliability by only detecting abnormalities when the feedback comparison shows significant deviations that exceed normal operational variations.
Data Source
AI summary
To carry out diagnosis of a current sensor while maintaining high reliability. An inverter control device according to the present invention controls an inverter circuit, calculates an estimated direct current value on the basis of a duty value and an alternating current sensor value output by an alternating current sensor, and performs diagnosis of a direct current sensor on the basis of the estimated direct current value and a direct current sensor value output by the direct current sensor.