Common-ground five-level single-phase photovoltaic inverter and control method thereof

The invention discloses a common-ground five-level single-phase photovoltaic inverter based on switched capacitors and a control method thereof, the inverter comprises two split capacitors on a direct current side, five switch tubes, one switched capacitor, a diode and a network side filter, and the switch tube S2 is a bidirectional switch. The photovoltaic negative electrode of the inverter is directly connected with the negative end of the power grid; the switching tubes S1, S2 and S3 form a half-bridge T-type three-level circuit and are connected with the direct current side split capacitor. The emitters of the switching tubes S4 and S5 are connected with one end of the filter, and the collectors are connected with the two ends of the switched capacitor respectively; the anode of the diode D1 is connected with the collector of the switching tube S5, and the cathode is connected with the negative end of the power grid. The five-level inverter topology provided by the invention has fewer switching devices, a