A New Switching Time Calculation Algorithm for SPWM Three-Phase Voltaje Source Inverter

The voltage source inverter has become an important component for renewable energy sources. This inverter uses Sinusoidal Pulse Width Modulation (SPWM) as the most common method for inverter controlling due to presents some advantages to other modulation techniques as, output voltage harmonic content reduction, the power loss in the switching devices is low and can be easily implemented using a digital controller. However, the SPWM technique can be improved by mean of the own concepts, thus a simple and practical implementation can be achieved. In this paper, a simple and effective methodology for switching time calculation for a SPWM three phase inverter is presented. A detailed methodology and algorithm are provided to program three independent microcontrollers, one for each phase, which must be synchronized to produce the right modulation. Therefore, the three phases are handled independently, and each phase can be controlled in a decoupled mode. In addition, the programming can be carried out in any programming software for simple and known functions, in this case MATLAB is used. In order to assess the proposed methodology and corroborate the inverter proper behavior, the microcontrollers simulation with the calculated switching times in ISIS software is performed.