EV Charging Inverter Control for Current Sensor Deterioration
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Solution Overview
Problem
Conventional electric vehicle charging systems face challenges in controlling current imbalances due to deteriorated current sensors, leading to output limitations and charging interruptions caused by increased IGBT temperatures, especially under adverse conditions like high outside temperatures or high current charging.
Innovation Solution
A method and apparatus that determine current sensor deterioration by comparing IGBT temperature sensing values across phases and adjust the current sensor scale in real-time to maintain charging stability, preventing further temperature increases and ensuring balanced current control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional current sensor scale is used for charging control, then the charging system operates normally under ideal conditions, but current imbalance control fails when the current sensor deteriorates, leading to IGBT overheating and charging interruption
Solution Approach 1:
The patent applies dynamics by making the current sensor scale adjustable rather than fixed. The scale is dynamically updated based on detected IGBT temperature differences across phases. When sensor deterioration is detected through temperature imbalance, the scale for the affected phase is automatically adjusted to compensate, maintaining accurate current control despite sensor degradation.
Solution Approach 2:
The patent implements feedback by continuously monitoring IGBT temperatures across all phases and using this information to detect current sensor deterioration. The temperature differences serve as feedback signals that trigger scale adjustment, creating a closed-loop system that automatically compensates for sensor degradation to maintain reliable charging operation.
2Reliability
If the current sensor deteriorates, then the MCU recognizes incorrect current values, but the system lacks the capability to detect or compensate for this deterioration, causing phase current imbalance and increased IGBT temperatures
Solution Approach 1:
The patent uses IGBT temperature as an intermediary indicator to detect current sensor deterioration. Instead of directly measuring sensor accuracy, the system monitors the temperatures of IGBTs across phases as a proxy. Temperature imbalances reveal current imbalances caused by sensor deterioration, enabling indirect detection and compensation without requiring direct sensor validation.
Solution Approach 2:
The patent replaces direct electrical current measurement validation with thermal field monitoring. By substituting the mechanical/electrical sensing approach with thermal sensing of IGBT temperatures, the system gains an alternative measurement modality that can detect sensor deterioration through temperature patterns rather than relying solely on electrical measurements.
3Productivity
If high current charging is performed to increase charging speed, then charging productivity improves, but IGBT temperatures increase further, exacerbating the effects of current sensor deterioration and risking overtemperature shutdown
Solution Approach 1:
The patent applies preliminary action by proactively adjusting current sensor scales based on temperature trends before overtemperature shutdown occurs. The system continuously monitors temperature differences and preemptively compensates for sensor deterioration by updating scales, preventing the escalation to critical overtemperature conditions that would force charging interruption.
Data Source
AI summary
A charging control method for an electric vehicle is configured to boost a charging voltage by using a motor and an inverter, and includes steps of determining whether a current imbalance control is normally operated based on currents input from the motor to three-phase inputs of the inverter during charging, determining whether a current sensor is deteriorated based on a result of an internal temperature sensing of the inverter when the current imbalance control is in a normal operation, and adjusting a scale of the current sensor to maintain the charging, when a deterioration of the current sensor is detected, as a result of the determination.