Power quality improvement of a class of reduced device count inverter

This paper presents a method to improve the power quality of a class of shared inverter topologies utilizing optimal sorting and the offsetting pulsewidth modulation (PWM) method. For the (3n + 3)-switch converter topologies, a PWM procedure with two degrees of freedom is proposed to enhance the quality at the power side of the shared loads without adding more passive elements. Moreover, the two degrees of freedom are analyzed and optimized to improve the power quality of the output current of the shared loads. The optimization is achieved using particle swarm optimization (PSO) method in which three objective functions are formulated, each of which impacts the power quality at the shared load sides. The objective functions are: the total harmonic distortion (THD), the scaled total harmonic distortion (STHD), and the summation of the eleventh order of harmonics (SFEH) of the current of the shared loads. A case study that compares the PSO results with the conventional results is investigated to highlight the effectiveness of the proposed procedure. Furthermore, a test bed is built and the proposed procedure is experimentally investigated, verified, and compared to the simulation.