How to ensure reliable control when EPS voltage drops?

When the mains voltage drops, the EPS needs to maintain reliable control and ensure normal emergency switching functionality. This requires coordinated hardware and software design.

Hardware aspects:

1. Wide input range auxiliary power supply: The auxiliary power supply for the control board and drive circuits should have a wide input voltage range (e.g., AC/DC 85-305V) to maintain stable output even when the mains power drops.

2. Critical voltage monitoring and holding: Monitor the MCU core voltage and use large-capacity energy storage capacitors or supercapacitors as temporary backups when necessary to maintain power supply to the control system during switching.

Software/control aspects:

1. Fast voltage detection algorithm: Real-time detection of mains voltage to quickly identify voltage drop events.

2. Seamless switching logic: The control algorithm needs to achieve a fast and smooth switch to inverter output mode after a mains fault, avoiding output interruption or large shocks.

3. Watchdog and status protection: Strengthen the software watchdog and save critical operating states in non-volatile memory to prevent the program from crashing during voltage disturbances and to quickly resume operation after recovery.