Single-phase nine-level SHE-PWM inverter with single DC source suitable for renewable energy systems

This paper presents an efficient nine-level inverter controlled by selective harmonic elimination pulse width modulation (SHE-PWM) method. The proposed inverter circuit is supplied with a single DC voltage source which makes it a very attractive for renewable energy systems e.g. inverter-based PV systems and fuel cell. The proposed method employs a single multi-winding transformer with two-winding of different turn numbers at the primary side and one-winding at the secondary side to synthesis the multilevel waveform. The device-account is considerably reduced when compared with conventional multilevel inverters for the same number of output voltage levels. The quality of the output voltage is enhanced using the SHE-PWM technique which guarantees the elimination of the low order harmonics and the magnetizing inductance of the transformer will get rid of high order of harmonics. The effectiveness of the proposed inverter is validated with different cases using simulation studies.