Symmetry-Based Simulation of a Dual Inverter Under Different Load Conditions

Abstract

This paper presents a symmetry-based analysis applied to a dual-inverter system that powers different types of loads. The configuration consists of two three-phase inverters controlled using carrier-based space-vector pulse-width modulation (CBSV-PWM). The study investigates how the phase-shift angle α between the two inverters influences multilevel voltage synthesis and the resulting electrical behavior of the system. The main contribution is the systematic characterization of the complementary angular symmetry between phase-shift α and 360°-α, establishing their relationship with the differential output-voltage magnitude and the resulting voltage and current waveforms. The complete phase-shift range from 0° to 360° is evaluated to identify the evolution of the synthesized voltage and the symmetry between complementary operating points. Resistive, resistive–inductive, and induction-motor equivalent loads are considered to examine the influence of the load characteristics on the system response. PSIM simulation results show that complementary phase-shift pairs exhibit closely corresponding voltage behavior, while the maximum differential-voltage magnitude occurs around α = 180°. The results demonstrate that the phase-shift angle provides a systematic means of characterizing the voltage-synthesis behavior of the dual-inverter configuration and its complementary angular symmetry under different load conditions.