Analysis and Simulation of Various PWM Control Techniques for Solar Power Grid-Tied Inverter

Abstract

PV (Photo-Voltaic) grid-connected is the emerging trend of solar system application, and grid-tied inverter is one of the key gears in PV grid-connected systems. Grid-Tied Inverter (GTI) systems are required to operate in parallel with electric grid. GTI are quite similar to that of conventional dc-ac converters, when it is compared for the power processing units, despite of control algorithm and safety features. Basically, GTI fetches variable dc source from solar panels and inverts it to ac through inverter, synchronized with the mains. The dc-dc boost converter circuit, along with conventional controlling technique and various PWM controlling techniques such as 1800 conduction mode, SPWM (Sinusoidal Pulse Width Modulation) and SVPWM (Space Vector Pulse Width Modulation) are used in the system with the function of Maximum Power Point Tracking (MPPT) algorithm. When the solar array generates additional power, despite of being used in the applications, the surplus is exported to the grid, and when the solar array generates a lesser amount of power, the difference is imported from the grid for the applications. The overall efficiency of the system depends on the efficiency of the Sunlight rays (photons)-into-dc and the dc-into-ac conversion efficiencies. The output power of photovoltaic (PV) module varies with module temperature, solar insolation, tilt angle and load changes. The controlling technique improves the performance of the system which gives significant output for PV grid-tied inverter applications. According to the specification and desired requirement, the inductor is design for the dc-dc boost converter. The dc-dc boost converter is further implemented on hardware part along with the integration of solar panel and various testing parameter are carried out for different conditions such as variation in irradiation, duty cycle and switching frequency. The boost converter is further linked with the inverter section, which is having different switching techniques, in which the firing of six IGBTs will lead to the generation of sinusoidal output. The sine output is further delivered to the grid and various other industrial and domestic applications. In order to showcase the output power of grid-connected PV system according to the output power of PV arrays, the results are carried out in simulation based softwares.