The voltage control in single-phase five-level inverter for a stand-alone power supply application

Abstract

Inverters have been widely used since more devices require alternating current (AC) voltage source. However, these devices require a stable AC voltage source, so that the device is not easily damaged. The solution is to control the inverter output voltage to be applied as a standalone power supply. The main problem is that standalone power supplies generally use conventional inverters. Conventional inverters require high switching frequencies and large inductance filters so that harmonic distortion at undesirable voltages that affect the durability of electrical equipment does not exceed the IEEE 519 standard. The purpose of this research is to provide a solution using a single-phase five-level inverter for stand-alone power supply applications. This research method applies a new control strategy on sinusoidal pulse width modulation (SPWM) to control the output voltage of a single-phase five-level inverter. The SPWM signal is generated by comparing two sinusoidal reference signals that are shifted 180 degrees with two cascaded carrier signals. This research has been verified by simulating, implementing, and testing the THD voltage in the laboratory. As a result, the output voltage of the five-phase single-phase inverter has been controlled based on the reference voltage with a voltage THD value of 4.39%. This meets the standard THD voltage from IEEE 519 below 5%, so it can be applied as a stand-alone power supply. Another advantage, this inverter uses an asymmetric topology with fewer power switches compared to other topologies of five-level inverters.