Level conversion circuit, inverter and energy storage system thereof

The embodiment of the invention discloses a level conversion circuit, an inverter and an energy storage system thereof. The level conversion circuit comprises N controlled driving units of which the direct current sides are connected with a direct current side voltage source, and the controlled driving units are configured to respond to direct current side voltage and correspondingly output first voltage, second voltage or third voltage under the control of a control unit; the voltage ratios of the transformers are in an equal-ratio increasing trend; the alternating current sides of the controlled driving units are connected with the primary sides of the corresponding transformers, the secondary sides of the N transformers are connected in series and then output a modulation voltage with 3Nn levels, and under the control of the control unit, the modulation voltage is equivalent to an alternating current voltage; the equal ratio of the voltage ratios of the N transformers is n. The alternating voltage is modul