To control the solar power, reliability and stability are two main challenges. In addition, the total harmonic distortion (THD) must be within limits for optimal operation. In an inverter, the harmonics are produced during the conversion of DC power to AC power, which will affect the power electronic devices. Therefore, to overcome such challenges in high voltage and high power systems multilevel inverter (MLI) topology is more useful. Such type of inverters uses various DC voltage levels to generate the stepped AC at its output, approaching the sinusoidal shape. The cascaded H-bridge, capacitor-clamped, and diode-clamped are the most commonly used multilevel inverters topologies. For photovoltaic (PV) usage, cascaded H-bridge (CHB) MLI is more adaptive among the three topologies, where for each H-bridge unit; each PV model behaves as an isolated DC source. This paper specifically focused on the simulation of PV power as a source to the system and displayed the potential of a single-phase 11-level CHB inverter. For switching the IGBT devices, sinusoidal pulse width modulation (SPWM) is applied. Moreover, the fuzzy logic control (FLC) is introduced to improve the power quality. FLC reduce the THD via finding the appropriate set of IGBT switch signals. To show the improvement in the operation and reduction in the complex harmony signal effects of the CHB 11-level inverter, the proposed system is designed in Matlab/Simulink software. Finally, the results show that the dynamic behavior of the FLC is much better than the traditional proportional integral derivative (PID) controller.
Simulation of single phase photovoltaic system based on fuzzy logic control with multilevel inverter
