AC Input Voltage Sensor Diagnosis in EV Charging Systems
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Solution Overview
Problem
The existing charging systems for eco-friendly vehicles, such as electric and plug-in hybrid vehicles, face issues with delayed or impossible charging due to malfunctions in alternating current (AC) input voltage sensors, which are not accurately diagnosed, violating vehicle-related standards.
Innovation Solution
A charging system with a sensor diagnosis function that includes an AC input voltage sensor, a resistor, a power factor correction circuit, a capacitor, and a controller to estimate the resistance value of the resistor and diagnose the sensor based on current and voltage values, comparing detected and estimated AC input voltage values to determine the sensor's state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an AC input voltage sensor is installed to detect external AC input voltage, then charging control can be performed, but the sensor may malfunction causing charging delays or impossibility
Solution Approach 1:
The system performs preliminary diagnosis of the AC input voltage sensor before charging operations. The controller calculates expected sensor values based on circuit parameters (resistor values, capacitor voltages, current measurements) and compares these with actual sensor readings to detect malfunctions in advance, preventing charging delays caused by undetected sensor failures.
Solution Approach 2:
The system implements a feedback mechanism where the controller continuously monitors the AC input voltage sensor by comparing its output against calculated expected values derived from other circuit measurements. When discrepancies exceed predetermined thresholds, the system identifies sensor malfunction and adjusts charging operations accordingly, ensuring reliable charging control.
2Reliability
If sensor diagnosis function is added to detect sensor malfunction, then charging reliability is improved, but device complexity increases
Solution Approach 1:
The system performs self-diagnosis of the AC input voltage sensor using existing circuit components and measurements. The controller calculates expected sensor values based on known circuit parameters (resistor values, capacitor voltages, current measurements) and autonomously compares these with actual sensor readings to detect malfunctions, eliminating the need for additional dedicated diagnosis hardware.
Solution Approach 2:
The controller serves multiple functions: it manages normal charging operations, monitors circuit parameters, performs sensor diagnosis, and controls charging based on diagnosis results. By making the controller multi-functional, the system avoids adding separate dedicated diagnosis equipment, thereby improving reliability without proportionally increasing device complexity.
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
This solution enables accurate and timely diagnosis of AC input voltage sensors, preventing charging delays and ensuring compliance with vehicle standards by using a controller to estimate resistance and voltage values, thereby improving the reliability of the charging system.
Implementation Method 1
the resistor may have a varied resistance value based on temperature
Data Source
AI summary
A charging system with a sensor diagnosis function is provided. The system includes an AC input voltage sensor that detects a voltage of an input end with an AC power applied thereto and a resistor that is connected to the input end. A power factor correction circuit unit adjusts and outputs a power factor of AC power applied through the resistor. An output voltage of the power factor correction circuit unit is applied to a capacity of the system. A controller then diagnoses the AC input voltage sensor based on a value of current passing through the resistor, a value of a voltage of the capacitor, and a resistance value of the resistor.