EV Charger Fault Detection for Poor Plug Contact
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Solution Overview
Problem
Existing electric vehicle chargers face safety issues due to inaccurate temperature sensing and potential arc sparks from poor plug connections, which can lead to accidents and unreliable operation.
Innovation Solution
A charger that senses faults in the line or poor plug contact by measuring voltage and current, controlling output current based on these measurements, and periodically checks for connection reliability, eliminating the need for a temperature sensor and reducing the risk of temperature increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a temperature sensor is used to control output current, then temperature-based protection is provided, but measurement accuracy deteriorates due to sensor errors
Solution Approach 1:
The patent replaces the temperature sensor-based thermal detection system with an electrical measurement system that monitors line voltage and current. Instead of measuring temperature directly (which has sensor errors), the system measures electrical parameters (voltage and current) that indicate connection quality and calculates resistance to detect faults, thereby substituting a more accurate measurement approach.
2Temperature
If output current is controlled based on temperature, then overheating is prevented, but the temperature is already increased making internal circuits unreliable
Solution Approach 1:
The system performs preliminary detection of line faults and poor connections by monitoring voltage and current before significant temperature increase occurs. By detecting resistance abnormalities early in the charging process, the system can prevent or adjust current before thermal damage affects internal circuits, rather than reacting after overheating has already occurred.
3Ease of operation
If manual power switch is used to control current flow, then user safety is improved, but operation reliability deteriorates due to user mistakes
Solution Approach 1:
The system replaces manual user control with automated electronic control that continuously monitors charging conditions. The controller automatically adjusts or interrupts current based on detected faults (line issues, poor connections, temperature), eliminating the need for users to manually operate power switches and preventing errors from improper manual intervention.
4Device complexity
If plug connection is not monitored, then device complexity is reduced, but harmful factors increase due to arc sparks from poor connections
Solution Approach 1:
The system implements continuous feedback monitoring of voltage and current during charging operations. By measuring these parameters and comparing them against expected values, the system can detect poor plug connections and line faults in real-time, providing feedback that triggers current interruption or adjustment to prevent arc sparks and associated damage.
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 enhances user safety by preventing accidents and improving operational reliability by immediately detecting line faults and ensuring proper plug connections, while also simplifying the charger design and reducing costs by eliminating the need for temperature sensors.
Implementation Method 1
the controller receives a line voltage and a line current across the line resistor; and controls a charging operation based on the received line voltage and line current
Data Source
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AI summary
A charger body (110) of a charger for electric vehicles comprises: an internal line resistor disposed between a wall outlet and a first connector (120), one end of internal line resistor being connected to the wall outlet and the other end of the internal line resistor being connected to the first connector; a switch, one end of the switch being connected to the first connector and the other end of the switch being connected to one end of the internal line resistor; relays, one end of each of the relays being connected to the first connector and the switch and the other end of each of the relays being connected to a second connector (130); and a controller controlling operation of the switch and the relays depending on a predetermined operation mode.