Line Voltages THD Optimization on a Multilevel Inverter for PV Systems

Abstract: This paper presents the optimization of total harmonic distortion (THD) applied directly to the line voltages output from a multilevel power inverter, with H-bridges cascaded common source of nine steps per phase applied to a photovoltaic system. The mathematical model of the THD of line voltages is presented in terms of commutation angles of the PWM phase modulation following the IEEE-519 standard. This equation gives a new and purely numerical optimization character, allowing to obtain excellent results using genetic algorithms reaching a THD of 0.3% in line voltages. To validate the results obtained by mathematical modeling and optimization, an algorithm using the FPGA Virtex5 XUPV5-LX110T is implemented.