Vehicle Power Converter Control for Sensor Fault Charging
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Solution Overview
Problem
Existing vehicle power source devices face challenges in continuing external charging without excessive ripple current when an abnormality is detected in one of the current sensors corresponding to multiple phases of an electric motor, potentially leading to interrupted charging.
Innovation Solution
A vehicle power source device with a control system that executes a ripple restraining control by adjusting the phase difference of switching elements in normal phases to 180° and restricts input current when temperature thresholds are exceeded, ensuring the ripple current does not exceed allowable limits, thus allowing continuous charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
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 pattern of the power conversion device based on the detected abnormality. When a current sensor abnormality is detected, the control device switches from normal three-phase operation to a modified two-phase operation mode, dynamically adapting the system's operating characteristics to maintain charging while managing ripple current through real-time control adjustments.
Solution Approach 2:
The patent changes the operational parameters of the power conversion device by modifying the switching element control strategy. Specifically, it adjusts the conduction periods and switching sequences of the remaining normal phases, changing the electrical parameters to ensure that ripple current remains within acceptable thresholds while maintaining charging functionality.
2Object-generated harmful factors
If switching elements in normal phases are controlled to maintain ripple current below threshold, then harmful effects are reduced, but charging efficiency may be compromised
Solution Approach 1:
The patent ensures continuous charging operation by maintaining the useful action of power transfer throughout the abnormal condition. The control device keeps the power conversion device operating in a modified mode rather than shutting down, ensuring that charging continues uninterrupted while ripple current is managed through controlled switching patterns of the remaining normal phases.
Solution Approach 2:
The patent converts the harmful situation of sensor abnormality into a manageable operating condition. By detecting the abnormality and automatically switching to a restricted two-phase mode, the system transforms a potentially dangerous ripple current situation into a controlled operating state where charging continues safely, effectively using the abnormality detection capability to initiate a beneficial protective response.
3Reliability
If ripple current is restrained by controlling switching elements, then system reliability is improved, but device complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the control device continuously monitors current sensor status and detects abnormalities. Based on this feedback, the system automatically adjusts its operating mode, switching from normal three-phase operation to modified two-phase operation when needed. This closed-loop feedback approach maintains system reliability through automatic adaptation without requiring complex external control systems.
Solution Approach 2:
The power conversion device performs self-diagnosis and self-adjustment when a current sensor abnormality is detected. The control device within the system autonomously identifies the abnormal condition and implements the appropriate control strategy modification, enabling the system to service itself without external intervention. This self-service capability maintains reliability while avoiding the need for additional complex external control equipment.
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 continuous external charging while effectively managing ripple current and temperature, preventing interruptions due to sensor abnormalities and maintaining efficient power transfer.
Implementation Method 1
an external power source is connected to a neutral point of an electric motor for vehicle traveling... electric power supplied from an external power source through a neutral point of the electric motor is boosted and thereafter is supplied to the battery
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
When an abnormality of one of current sensors (20) corresponding to a plurality of phases is detected during charging, a control device (16) of a vehicle power source device (10) configured to execute a ripple restraining control to continue the charging while controlling switching elements (Q1, Q2) in remaining normal phases of the plurality of phases such that a ripple current (Ir) to be generated by operation of the switching elements (Q1, Q2) in the normal phases does not exceed a ripple current threshold (THr). The ripple current threshold (THr) corresponds to an allowable value of the ripple current (Ir) to be generated by operation of the switching elements (Q1, Q2) in the plurality of phases when there is no abnormality in any of the current sensors (20) corresponding to the plurality of phases.