On-board Charger Insulation Detection Circuit
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Solution Overview
Problem
Existing insulation detection methods for on-board chargers in electric vehicles are cumbersome, not easily operable, and lack real-time monitoring capabilities, posing a risk of electric shock and component damage due to inadequate insulation detection between live and ground lines.
Innovation Solution
An insulation detection circuit and method that detects insulation impedance between the AC output and the vehicle body in an inverting mode using Y capacitors, sampling circuits, and a controller to determine insulation failure, ensuring safety by monitoring voltage balance and impedance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional insulation detection methods are used, then detection can be performed, but the operation is cumbersome and real-time monitoring is not achieved
Solution Approach 1:
The insulation detection circuit is integrated into the on-board charger system, enabling the system to automatically monitor its own insulation status without requiring external instruments or manual operations. The controller continuously acquires voltage signals from the sampling circuit and automatically determines insulation failure states,实现ing self-service monitoring that eliminates operational complexity while maintaining real-time detection capability
Solution Approach 2:
The system implements continuous feedback monitoring by constantly acquiring voltage signals from the AC output lines through the sampling circuit, processing these signals through the controller, and immediately determining insulation status. This closed-loop feedback mechanism ensures real-time monitoring capability while keeping the system simple to operate
2Reliability
If insulation detection is not implemented, then the structure remains simple, but safety risks such as electric shock and component damage occur
Solution Approach 1:
The insulation detection function is merged with the existing on-board charger control system. The sampling circuit shares the AC output lines with the charging function, and the controller integrates insulation detection with the existing control logic. This merging approach enhances safety by adding insulation monitoring while avoiding the need for separate independent detection equipment, thus limiting the increase in structural complexity
Solution Approach 2:
The controller serves multiple functions: it controls the normal charging operation and simultaneously performs insulation detection by processing voltage signals from the sampling circuit. The sampling circuit also serves dual purposes by monitoring both operational parameters and insulation status. This multi-functionality approach improves safety 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
The solution provides real-time detection of insulation failures, preventing electric shock and enhancing safety and reliability of on-board chargers with a simple, practical, and cost-effective structure.
Implementation Method 1
a first Y capacitor C1 connected between an output live line and a ground line of the inverter circuit, a second Y capacitor C2 connected between an output neutral line and the ground line
Data Source
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AI summary
The present invention discloses an insulation detection circuit and a detection method thereof for a two-way on-board charger. The detection circuit comprises an inverter circuit, a first Y capacitor connected between an output live line and a ground line of the inverter circuit, a second Y capacitor connected between an output neutral line and the ground line of the inverter circuit, a live line sampling circuit and a neutral line sampling circuit which are connected with the output live line and the output neutral line of the inverter circuit, and a controller. The controller determines an insulation state of the two-way on-board charger according to two sampling voltages.