Interval Type 2 Fuzzy-Logic-Based Solar Power MPPT Algorithm Connected to AC Grid

In this article, an interval type-2 fuzzy logic controller (IT2FLC) is used as a Maximum Power Point Tracker (MPPT) to supply a large scale interconnected grid. The IT2FLC has the advantage of being able to regulate the MPP in case of severe variations of the weather conditions. A photovoltaic array is connected to AC grid via a DC-DC boost converter and a three-phase three-level Voltage Source Converter (VSC). The duty cycle of the boost converter is switched by the IT2FLC. A three phase VSC converts the V-DC link voltage to AC and keeps unity power factor. The VSC control system uses two control loops: an external control loop which regulates DC link voltage to alternative current and an internal control loop which regulates the active and the reactive grid currents. Vd and Vq voltage outputs of the current controller are converted to three modulating signals used by the PWM Generator.