Fuzzy logic controller for a photovoltaic array system to AC grid connected

Abstract

This research described a PV system supplied a large scale interconnected grid. A PV array is connected to AC grid via a DC-DC boost converter and a three-phase three-level Voltage Source Converter (VSC). Maximum Power Point Tracking (MPPT) is implemented in the boost converter by means of a Simulink model using the integral regulator technique. The fuzzy logic control are using to control of voltage source converter. Also a conventional PID control is using to damp a variation of output voltage. PV array delivering a maximum power at 1000 W/m⁁2 sun irradiance. Boost converter increasing voltage from PV natural voltage DC at maximum powe. Switching duty cycle is optimized by a MPPT controller that uses the integral regulator' technique. This MPPT system automatically varies the duty cycle in order to generate the required voltage to extract maximum power. A three phase VSC converts the 500 V DC link voltage to 260 V AC and keeps unity power factor. The VSC control system uses two control loops: an external control loop which regulates DC link voltage to 250 V and an internal control loop which regulates Id and Iq grid currents (active and reactive current components). Id current reference is the output of the DC voltage external controller. Iq 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. The control system uses a sample time of 100 microseconds for voltage and current controllers as well as for the PLL synchronization unit. Pulse generators of Boost and VSC converters use a fast sample time of 1 microsecond in order to get an appropriate resolution of PWM waveforms. The power full of proposed fuzzy control is fast than conventional PID control.