Vehicle Power Source Charging Control Under Current Sensor Faults
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Solution Overview
Problem
Existing vehicle power source devices may stop external charging due to excessive ripple current when an abnormality is detected in one of the current sensors corresponding to multiple phases of an electric motor.
Innovation Solution
A vehicle power source device that includes a battery, an electric power conversion device with switching elements and current sensors for multiple phases, and a control device. The control device executes a ripple restraining control by controlling the switching elements in remaining normal phases to ensure the ripple current does not exceed a threshold, allowing continuous external charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external charging is continued using remaining normal phases after current sensor abnormality detection, then charging availability is improved, but ripple current increases excessively
Solution Approach 1:
The patent dynamically adjusts the switching element control strategy based on the detected abnormality. When a current sensor abnormality is detected during external charging, the control device switches from normal three-phase operation to a modified two-phase operation mode, dynamically adapting the system behavior to maintain charging while managing ripple current through phase-specific control adjustments
Solution Approach 2:
The patent changes the operational parameters of the power conversion device by modifying the switching patterns and control parameters for the remaining normal phases. The control device adjusts switching duty ratios, frequency, and timing for the healthy phases to optimize the balance between maintaining charging function and restraining ripple current within acceptable limits
2Object-generated harmful factors
If switching elements in remaining normal phases are controlled to restrain ripple current, then ripple current is reduced, but charging efficiency may be compromised
Solution Approach 1:
The patent applies partial action by focusing ripple current restraint efforts only on the critical aspects that can be controlled through the remaining normal phases. Rather than attempting to achieve complete ripple elimination or maintain full three-phase power transfer, the system accepts partial performance degradation while successfully restraining ripple current to acceptable levels through targeted control of the available phases
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
The vehicle power source device effectively continues external charging while restraining ripple current, ensuring reliable charging operations even when an abnormality is detected in one of the current sensors.
Implementation Method 1
an electric power conversion device that converts an input voltage supplied from an external electric power conversion device into a charging voltage for an in-vehicle electricity storage device
Data Source
AI summary
When an abnormality of one of current sensors corresponding to a plurality of phases is detected during charging, a control device of a vehicle power source device configured to execute a ripple restraining control to continue the charging while controlling switching elements in remaining normal phases of the plurality of phases such that a ripple current to be generated by operation of the switching elements in the normal phases does not exceed a ripple current threshold. The ripple current threshold corresponds to an allowable value of the ripple current to be generated by operation of the switching elements in the plurality of phases when there is no abnormality in any of the current sensors corresponding to the plurality of phases.