Interval Type 2 Fuzzy-Logic DC Link Voltage Controller on Grid Connected PV System

This paper focuses on control strategy of the direct current link voltage of a voltage source converter based on an interval type 2 fuzzy logic controller. A PV array is connected to alternative current (AC) grid via a boost converter and a three-phase three-level voltage source converter. The three phase VSC converts the DC link voltage to AC and keeps unity power factor. The VSC control system uses two controllers. The first one is an external interval type 2 fuzzy controller which regulates the DC link voltage to its reference value and the second regulates active and reactive grid current components. The active current reference is the output of the DC voltage external controller. the reactive current reference is set to zero in order to maintain unity power factor. Vd and Vq voltage outputs of the current controller are converted to three modulating signals used by the PWM Generator. Result from the simulation shows that the IT2 F controller is capable to stabilize the DC link voltage in the vicinity of reference value in various temperature and irradiation condition.