Electric Power Control Unit Sensor Failure Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electric vehicles become incapacitated for travel when even one current sensor fails, as existing systems lack the ability to detect and adapt to failures in multiple current sensors, leading to uncontrolled drive power delivery.
Innovation Solution
An electric power control unit equipped with multiple current sensors and a controller that compares measured values to detect failures and continue drive power control using remaining sensors, ensuring the electric motor can operate even if one sensor fails, by calculating phase currents and adjusting power supply accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple current sensors are arranged to detect failures, then reliability is improved, but device complexity increases
Solution Approach 1:
The controller compares measured values from multiple current sensors during a shutdown period before actual operation to detect failures in advance. This preliminary detection allows the system to identify faulty sensors before they affect motor control, resolving the contradiction by enabling failure detection without requiring continuous operation of all sensors.
Solution Approach 2:
The patent uses multiple current sensors as redundant copies to measure the same phase current. By arranging duplicate sensors and comparing their outputs, the system can detect failures without significantly increasing overall system complexity, as the additional sensors are simple measurement devices rather than complex control components.
2Productivity
If control continues with remaining sensors after one fails, then productivity is maintained, but reliability deteriorates due to undetected abnormalities
Solution Approach 1:
The system performs failure detection during shutdown periods before operation begins. By comparing sensor readings when no current should be flowing, the controller identifies faulty sensors in advance, ensuring that only functional sensors are used during actual motor control. This maintains reliability while allowing continuous operation with remaining good sensors.
Solution Approach 2:
The controller continuously monitors and compares measured values from multiple current sensors, providing feedback on sensor health status. When discrepancies are detected during shutdown periods, the system adjusts control strategies to rely only on verified functional sensors, maintaining both productivity and reliability through continuous feedback monitoring.
3Reliability
If current sensors are provided with self-diagnostic functions, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
Instead of adding self-diagnostic functions directly to the current sensors, the patent introduces a controller as an intermediary that performs the diagnostic function. The controller compares measured values from multiple sensors during shutdown periods to detect failures, thereby achieving reliable autonomous detection without modifying the sensor structure itself.
Solution Approach 2:
The patent uses multiple current sensors as redundant copies and achieves self-diagnostic capability through their collective output comparison rather than through individual sensor self-diagnostics. This approach provides autonomous failure detection while keeping individual sensor structures simple and unchanged.
Data Source
AI summary
An electric power control unit configured to control drive power of a three-phase alternating current to be supplied to an electric motor may include: an inverter configured to convert a direct current to the three-phase alternating current; first and second current sensors, each of which is configured to measure a first-phase current in the three-phase alternating current; third and fourth current sensors, each of which is configured to measure a second-phase current in the three-phase alternating current; and a controller configured to control the inverter, and under a condition in which the first current sensor fails, when measured values of the second, the third, and the fourth current sensors do not coincide with each other while the inverter is shut down, the controller may stop to further supply the drive power to the electric motor.