The utility model relates to a
power supply voltage sag protector of super
capacitor energy storage and a control method thereof, belonging to the technical field of
voltage sag protection. The protector comprises a mains supply
voltage amplitude detection circuit, a mains supply
voltage current phase detection circuit, a
DC bus voltage detection circuit, a
DC bus current detection circuit, a super
capacitor voltage detection circuit, a load voltage detection circuit, a load voltage and current phase detection circuit, a super
capacitor charging and discharging circuit, a power supply switching module, a super capacitor group and a balanced voltage circuit, a SCM (
single chip microcomputer)
control unit, a
rectifier circuit, and a DC step-down circuit. The control method comprises a step of setting the
cut back time length of a power supply switching module, a step of inputting load two-end current phase and
grid voltage phase into the SCM
control unit, a step of monitoring whether a mains supply grid has
voltage sag or not, judging the voltage current phase at that time if so, and switching the mains supply grid power supply to super capacitor group power supply, and a step of switching the super capacitor group power supply into the mains supply grid power supply when the
grid voltage is restored to be normal.