Grid Connected Solar System with PWM Operated Thirteen Level Inverter using Digital PI Controller

Authors: S. Sunisith , M. Saritha and D. Krishna Chaitanya


Abstract

Grid connected solar system uses to have converter circuits followed by two levels: A DC/DC boosters and PWM Inverter. This combination of converters leads to decrement of Quality and efficiency of electric power. This paper proposes a single phase thirteen-level photo voltaic inverter for grid connected solar system with a novel pulse width modulated control scheme. The fast variations of solar radiation can be compensated by digital proportional-integral controller. The inverter offers less total harmonic distortion and good power factor. This inverter topology uses two reference signals instead of one reference signal to generate PWM signals for the switches. Both the reference signals Vref1 and Vref2 are identical to each other, except for an offset value equivalent to the amplitude of the carrier signal Vc. Because the inverter is used in a Photo Voltaic system, a proportional–integral current control scheme is employed to keep the output current sinusoidal and to have high dynamic performance under rapidly changing atmospheric conditions and to maintain the power factor at near unity. PV arrays are connected to the inverter via a dc–dc boost converter. The proposed system offers improved performance over five level inverters.

 

Index Terms

Solar System, Photo Voltaic Cell, Multilevel Inverter and PI Controller

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Grid Connected Solar System with PWM Operated Thirteen Level Inverter using Digital PI Controller