Design Of Grid-Connected Photovoltaic Inverter Digital Control Module

Abstract

This paper presents the design of control module of grid connected photovoltaic system. photovoltaic array is being widely used nowadays. Sun energy could be utilized by the use of photovoltaic systems. But the photovoltaic array output is highly non-linear to be directly connected to the utility grid. Hence the output is applied through  DC-DC boost converter. Output of converter is converted to AC using an inverter. Both the converter and the inverter is controlled by the digital control module. Control module generates PWM signals to operate the MOSFET switches of the inverter. PWM signal is in phase with the utility grid voltage. Hence the AC output voltage of the inverter also will be in phase with the grid voltage. Digital controller includes MPPT module and PI controller. MPPT algorithm makes sure that the photovoltaic output is taken at the maximum power point. PI controller stabilizes the output PWM signal. The controller is implemented using dsPIC30f.Tool used is MPLAB. Use of renewable resource makes the project highly attractive.