Comprehensive analysis of three- and five-phase PUC inverters with harmonic injection modulation techniques

Multiphase power electronic converters are gaining more popularity nowadays. Three-phase system is not enough to produce smooth torque in industrial application. So systems that have more than three phases are gaining popularity due to their smooth torque and more power than the three-phase systems for the same phase voltage and current. Selection of even number of phases is generally avoided because it degrades motor performance due to the coincidence of motor poles with each other. This paper deals with carrier-based pulse width modulation techniques with the third-harmonic and fifth-harmonic injections in three-phase and five-phase five-level packed U-cell (PUC) inverter. Harmonic injection gives improvement in DC bus utilization without going into the overmodulation region. The viability of this concept is verified by MATLAB/Simulink by taking the three-phase and five-phase VSI as an example. The relation between the three-phase and five-phase voltage and power is analyzed and verified mathematically. The PUC inverter comprises the least number of device count, so it can be a good option for multiphase application in industrial drives.