Don’t Cut Corners on Safety: A Deep Dive into AC EV Charger Emergency Stop Protection

In the realm of new energy charging infrastructure, the GB/T 18487.1-2023 standard suggests that power supply equipment "should" be equipped with Emergency Stop Protection. It is precisely this permissive wording that tempts some AC EV Charger manufacturers to remove this feature to cut costs. However, true safety protection is never as simple as "pressing a button to cut power." The emergency stop switch serves as an irreplaceable Safety Bottom Line for chargers.

The current mainstream emergency stop control logic in the industry is highly rigorous. The system begins with millisecond-level continuous monitoring of the stop signal. To prevent False Triggering, a critical Timing Verification mechanism is integrated: on the trigger side, once a stop signal is detected, the system must confirm the signal persists for over 100ms to filter out mechanical bouncing. Subsequently, the system immediately locks the protection status, achieving Physical Disconnection of the power circuit by opening the Relay and ceasing the transmission of the PWM Wave.

The recovery process is equally sophisticated. After the emergency button is released, the system requires the signal to remain stable for over 500ms and simultaneously verifies that the Control Pilot (CP) Signal has returned to normal (12V). This dual-validation mechanism ensures maintenance personnel have adequate time to troubleshoot hazards, preventing a restart before risks are cleared. Consequently, a well-designed emergency stop function represents the optimal balance between rapid response to genuine emergencies and avoiding unnecessary power interruptions.