Design and Real-Time Implementation of Transformer-less Pure Sine-Wave Inverter

Transformer is the basic building block of the classical photovoltaic inverter. However, it has certain drawbacks i-e difficult to install, heavy weight, add complexity to the system, in efficient and increase total harmonic distortion. Therefore, this paper presents the design and real-time implementation of 1kW transformer less pure sine wave inverter. Input to the inverter is the 12 V regulated DC voltage from photovoltaic panel and output is the standard grid output i-e 220V with 50Hz frequency. The proposed topology is the two stage inverter, the first stage is DC/DC converter connected with the Photovoltaic panel to boost the regulated 12V DC to 320V DC and second stage is DC/AC inverter controlled by high frequency Sinusoidal Pulse Width Modulation signal and output of inverter is connected to load through passive filter to provide pure sinusoidal 220V with 50 Hz frequency. The simulation results are presented by first developing the code of SPWM in MPLAB and then simulating the inverter in Proteus software. At last, it is real-time implemented and tested for resistive load and the output voltage and and current is displayed on LCD.