High Voltage Inter-lock (HVIL), a safe design method for monitoring the integrity of high voltage circuits with low voltage signals. In theory, the low-voltage monitoring circuit is connected to the high-voltage first, then disconnected, and the necessary advance amount is maintained in the middle. The length of time can be determined according to the specific situation of the project, such as 150ms, which is generally on the order of magnitude. Specific high-pressure interlock implementations, different projects may have different designs. The monitoring target is an electrical interface component such as a high voltage connector that requires manual operation to turn the circuit on or off.
In the high-voltage circuit of electric vehicles, the electrical components requiring HVIL function are mainly high-voltage connectors and manual maintenance switches (MSD).