Motor-Inverter Charging Control Under Current Sensor Failure
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Solution Overview
Problem
The existing multi-charging system using a motor-inverter for electric vehicles faces issues with charging failure when one of the three current sensors fails, leading to unsafe vehicle movement and inability to charge the battery to 800 V, as it relies on precise current monitoring across phases.
Innovation Solution
A multi-charging apparatus and method that includes a power converter, first and second sensing units, and a controller to detect sensor failures, adjust current values, and prevent motor rotation, allowing charging to continue even with one failed sensor by comparing output values and adjusting control duty values based on normal phase currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If three current sensors are used to monitor each phase of the motor for precise charging control, then charging reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent removes one current sensor from the three-phase motor monitoring system, extracting the redundant component while maintaining charging functionality. The controller compensates for the missing sensor data through calculation based on the two remaining sensors, thereby reducing device complexity while preserving charging reliability.
Solution Approach 2:
The patent creates a virtual copy of the missing current sensor signal through computational methods. The controller calculates the current value of the failed phase by using the relationship between the three phases and the data from the two functioning sensors, effectively replicating the information that would have come from the third sensor without physically installing it.
2Measurement precision
If three current sensors are installed for monitoring all motor phases, then measurement precision is improved, but the system becomes vulnerable to failure and requires redundant components
Solution Approach 1:
The patent prepares for sensor failure in advance by designing a control system that can operate with only two functional sensors. The controller includes pre-programmed algorithms to detect sensor failure and automatically switch to a degraded mode of operation, cushioning against the impact of component failure and maintaining system reliability.
Solution Approach 2:
The patent changes the operational parameters of the motor control system when a sensor fails. The controller adjusts the control strategy from three-phase independent control to a modified two-phase control mode, changing how current values are measured and used while maintaining adequate measurement precision for safe operation.
3Object-affected harmful factors
If the system stops charging when a current sensor fails, then safety is improved, but productivity decreases due to charging interruption
Solution Approach 1:
The patent converts the harmful effect of sensor failure into a beneficial outcome by enabling continued charging operation. Instead of stopping charging (which would be the safe but productivity-reducing response), the system uses the failure condition to switch to a specialized control mode that maintains safety while preserving charging functionality, thus converting a negative event into a manageable situation.
Solution Approach 2:
The patent implements dynamic adaptability in the charging system. The control mode automatically transitions from normal three-sensor operation to degraded two-sensor operation based on the actual system state. This dynamic response allows the system to maintain safety through real-time monitoring adjustments while preserving productivity by continuing the charging process without interruption.
4Ease of operation
If motor rotation is allowed during charging with sensor failure, then ease of operation is improved, but harmful factors increase due to unbalanced motor force
Solution Approach 1:
The patent applies preliminary anti-action by implementing control measures that prevent the development of unbalanced motor forces before they can cause harmful effects. The controller detects sensor failure and immediately adjusts the motor control strategy to maintain force balance, preventing the generation of harmful vibrations or mechanical stress while still allowing controlled vehicle movement.
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
Enables reliable charging and prevents motor rotation even with sensor failures, increasing control precision and potentially reducing design costs by removing redundant components.
Implementation Method 1
a power converter for converting a first voltage power source introduced into a motor into a second voltage power source larger than the first voltage power source to supply the second voltage power source to a battery
Implementation Method 2
a first sensing unit provided on each of three phases of the motor to sense each power source for the first voltage power source
Data Source
AI summary
A multi-charging apparatus includes a power converter, a first sensing unit configured to sense a power source introduced into the power converter from a motor or introduced into the motor from the power converter, and a controller configured to determine whether failure occurs in the first sensing unit, and execute a charging operation control for the power converter when a failure occurs.