How to reduce EMI spikes in EPS emergency switching circuits?

When EPS performs emergency switching after a power grid outage, the operation of relays or contactors and the instantaneous load on the inverter may generate large voltage and current transients and EMI spikes. Mitigation measures include:

1. Connecting a freewheeling diode or RC snubber circuit in parallel with the relay/contactor coil to suppress the high-voltage back EMF spikes generated when the coil is de-energized.

2. Controlling the switching sequence to implement a "break-before-connect" interlocking logic to avoid instantaneous short circuits or voltage overlap.

3. Using soft-start control for the inverter, gradually increasing output power after switching to avoid current surges to the battery and load.

4. Implementing filtering on the power and signal lines of the switching circuit, for example, using common-mode chokes and TVS diodes.

5. Ensuring the continuity of the system ground reference point before and after switching to avoid common-mode interference introduced by sudden changes in ground potential.