A new single-stage transformerless inverter for photovoltaic applications

In this paper a new single-stage transformerless inverter for photovoltaic (PV) application is proposed. Typical PV systems have multi-stage topology in order to perform different functions. These multi-stage inverters suffer from low efficiency and high components count. The proposed inverter is a combination of boost converter and half bridge inverter which can handle voltage boosting as well as feeding ac current to the grid in one stage. The introduced converter is transformerless which increases the overall efficiency and decreases cost, size and weight of the system. This topology has several desirable features like low switching losses, low total harmonic distortion (THD) and simple control technique. In this paper, operation principle, theoretical analysis and design of the proposed topology are discussed. Also, simulation and experimental results of a 100W inverter are presented to confirm the validity of theoretical analysis.