Abstract: A combined converter and inverter circuit is disclosed. A transformer has a primary winding connected across a DC source through two parallel switching thyristors with respective diodes and a secondary winding connected across two AC terminals through a filter. Two series thyristors with diodes are connected across the primary winding to be able to form closed current loops. In the DC-to-AC conversion the switching thyristors invert DC power to produce AC power including a reactive component flowing through the closed loop. In the AC-to-DC conversion the closed current loop causes the storage of electric power on the filter and the diodes across the switching thyristors rectify the stored power for charging the DC source.