Experimental Validation of a Three-Phase Voltage-Source Inverter with SPWM Modulation for Low-Voltage Microgrid-Oriented Applications

Abstract

This work presents the design, implementation, and experimental validation of an open-loop three-phase inverter prototype. The experimental campaign was carried out with a regulated 48 V DC bus, while the bus-monitoring circuit was dimensioned for a wider voltage range. Control was implemented on an STM32 using digital SPWM, with a 120° phase shift and an adjustable output frequency between 60 and 80 Hz. To reduce the risk of cross-conduction in the MOSFETs, dead-time insertion was configured in both hardware and firmware. Tests with resistive loads verified three-phase operation in star and delta configurations, with balanced line voltages under laboratory conditions. The efficiency close to 92% corresponds to the tested low-load condition. Characterization at higher power levels and harmonic-distortion measurements are proposed as the next validation stage.