Patent ID: 11949280
Assignee: ABB SCHWEIZ AG
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method for controlling an uninterruptable power supply,
wherein the uninterruptable power supply comprises a grid connection, a grid switch connected to the grid connection, a rectifier and an inverter interconnected via a DC link, an energy storage connected to the DC link, a load connection, to which the inverter is connected, and a bypass switch, which is connected in parallel to the rectifier, the DC link and the inverter between the grid switch and the load connection;
wherein the grid switch is a mechanical switch and the bypass switch is a semiconductor switch;
wherein the grid switch comprises a confirmation device configured to generate a confirmation signal in response to the uninterruptible power supply being disconnected from the grid connection;
the method comprising:
in a normal operation mode in which the bypass switch is opened, the grid switch is closed, the uninterruptable power supply is connected to a grid via the grid connection and connected to a load via the load connection, operating the rectifier in a rectifying mode, in which an AC current from the grid is converted to a DC current supplied to the DC link and operating the inverter to convert the DC current from the DC link into an AC current supplied to the load;
upon receiving a fault signal, which signals an electrical fault concerning at least one of the load and the grid, sending a disconnect signal to the grid switch to open the grid switch and disconnect the uninterruptable power supply from the grid; and
upon receiving the confirmation signal from the grid switch, which confirms disconnection from the grid, sending a closing signal to the bypass switch and sending a mode change signal to the rectifier to operate the rectifier in an inverting mode, in which a DC current from the energy storage is converted into an AC current, such that the load is supplied by the inverter and the rectifier.