A three-level inverter, wherein the three-level inverter comprises two direct current power supplies (C301, C302), power frequency rectifier transistors (Q301, Q302, Q303, Q304), a first equivalent transistor and a second equivalent transistor, wherein each of the two equivalent transistors (Q305, Q306) comprises a first transistor, a second transistor, and a diode; a source electrode of the first transistor is electrically connected to a source electrode of the second transistor; a gate electrode of the first transistor is electrically connected to a gate electrode of the second transistor; and one end of the diode is electrically connected to a drain electrode of the first transistor, and the other end of the diode is electrically connected to a drain electrode of the second transistor wherein a connection end of the first equivalent transistor and the second equivalent transistor is an output end of the three-level inverter, wherein the two direct current power supplies (C301, C302) are a first direct current power supply and a second direct current power supply respectively, wherein the power frequency rectifier transistors (Q301, Q302, Q303, Q304) comprise a first power frequency rectifier transistor and a second power frequency rectifier transistor, wherein a second end of the first power frequency rectifier transistor is electrically connected to a first end of the second power frequency rectifier transistor, and wherein a second end of the first direct current power supply and a first end of the second direct current power supply are electrically connected and grounded; characterized in that the three-level inverter further comprises: a third power frequency rectifier transistor, and a fourth power frequency rectifier transistor; and a first end of the first power frequency rectifier transistor is electrically connected to a first end of the first direct current power supply, a second end of the second power frequency rectifier transistor is electrically connected to the second end of the first direct current power supply, a first end of the third power frequency rectifier transistor is electrically connected to the first end of the second direct current power supply, a second end of the third power frequency rectifier transistor is electrically connected to a first end of the fourth power frequency rectifier transistor, and a second end of the fourth power frequency rectifier transistor is electrically connected to a second end of the second direct current power supply; wherein a second end of the first equivalent transistor is electrically connected to a first end of the second equivalent transistor, a first end of the first equivalent transistor, the second end of the first power frequency rectifier transistor, and the first end of the second power frequency rectifier transistor are electrically connected, and a second end of the second equivalent transistor, the second end of the third power frequency rectifier transistor, and the first end of the fourth power frequency rectifier transistor are electrically connected. a third power frequency rectifier transistor, and a fourth power frequency rectifier transistor; and a first end of the first power frequency rectifier transistor is electrically connected to a first end of the first direct current power supply, a second end of the second power frequency rectifier transistor is electrically connected to the second end of the first direct current power supply, a first end of the third power frequency rectifier transistor is electrically connected to the first end of the second direct current power supply, a second end of the third power frequency rectifier transistor is electrically connected to a first end of the fourth power frequency rectifier transistor, and a second end of the fourth power frequency rectifier transistor is electrically connected to a second end of the second direct current power supply; wherein a second end of the first equivalent transistor is electrically connected to a first end of the second equivalent transistor, a first end of the first equivalent transistor, the second end of the first power frequency rectifier transistor, and the first end of the second power frequency rectifier transistor are electrically connected, and a second end of the second equivalent transistor, the second end of the third power frequency rectifier transistor, and the first end of the fourth power frequency rectifier transistor are electrically connected.