UNINTERRUPTIBLE POWER SUPPLY CONVERTER CIRCUIT

Uninterruptible power supply converter circuit (100, 200, 300, 400), comprising a controlled switching element (102), a filter capacitor (104), and a split DC capacitor comprising a plus DC capacitor (106) and a minus DC capacitor (116) split at a DC-link mid-point (112). The controlled switching element (102), the filter capacitor (104), the plus DC capacitor (106) and the minus capacitor (116) are connected to each other at the DC-link mid-point (112) on a respective first side. A second side of the input filter capacitor (104) at an AC point (114) is coupled via an inductor element (110) to a second side of the controlled switching element (102), the second side of the controlled switching element being coupled to the second side of the plus DC capacitor (106) and the minus capacitor (116). The controlled switching element (102) is configured to be controlled such that a current from the AC point (114) via the inductor element (110) flows alternatingly to either the plus DC output capacitor (106) or the minus DC capacitor (116), and to the DC-link mid-point, respectively, thereby discharging the input filter capacitor (104).