Disclosed is single phase five-level inverter topology comprising a half-bridge inverter circuit with a floating capacitor which outputs five mutually different voltage levels including zero, wherein both the system cost and the size is reduced, the leakage current is eliminated substantially and high efficiency is achieved by using five-level half-bridge structure with only one AC filtering inductor. Provided also is three-phase five-level inverter topology wherein the voltage utilization is twice that of the present three-phase five-level half-bridge inverter under the same operating conditions; the AC filtering inductance is smaller than that of the three-level half-bridge inverter; the DC link mid-point voltage can be balanced without additional circuitry.