Active and reactive power control of grid-connected single-phase asymmetrical eleven-level inverter

Abstract

In recent times, multilevel inverters (MLIs) have become very popular for commercial and industrial applications. Here, an eleven-level inverter and its power flow control are presented. The presented topology has a lesser component count than other existing topologies, thus reducing the devices and overall cost of the inverter. This inverter comprises six bidirectional switches, two DC sources, one four-quadrant switch, and two capacitors for the voltage divider circuit. The conduction modes and corresponding switching states of the presented eleven-level inverter are shown in detail. Further, the apparent power control of the presented inverter under grid-connected operation is discussed, which provides simultaneous active and reactive power control over the power injected into the grid. Switching and conduction losses are calculated for 3 and 6 kVA grid injected power at 0.8 power factor lagging. The obtained results show that the total harmonic distortion (THD) of the inverter output voltage and grid current is 12.10% and 0.23%, respectively, under 6 kVA power transfer conditions. The real-time analysis is also carried out for 3 and 6 kVA power transfer conditions for the presented eleven-level inverter to validate the active and reactive power flow control.