Abstract: A method controls an UPS with a system having: first and second terminals, a switch having: first and second switch terminals respectively connected to the first and second terminals; first and second thyristors connected between the first and second switch terminals in anti-parallel; and an inverter connected to the second terminal and the energy store. Switch current and a first potential at the first terminal are detected. In a first fault, where the first potential drops past a first rule and the switch current rises above a second rule: a second potential at the second switch terminal is set using the inverter so the switch current becomes zero. Then the switch current is compared with a second threshold, and if it is exceeded, a first check result is positive, otherwise it's negative. When positive, the second potential is reversed.

Abstract: A method controls an UPS with a system having: first and second terminals, a switch having: first and second switch terminals respectively connected to the first and second terminals; first and second thyristors connected between the first and second switch terminals in anti-parallel; and an inverter connected to the second terminal and the energy store. Switch current and a first potential at the first terminal are detected. In a first fault, where the first potential drops past a first rule and the switch current rises above a second rule: a second potential at the second switch terminal is set using the inverter so the switch current becomes zero. Then the switch current is compared with a second threshold, and if it is exceeded, a first check result is positive, otherwise it's negative. When positive, the second potential is reversed.