An Improved Two-Stage Inverter with High Voltage Boosting Capability and Continuous Input Current Feasible for Low-Power Solar Applications

In this paper, an improved structure for two-stage inverters is proposed, which profits from high voltage boosting ability without using a transformer. The proposed structure consists of two main stages, including an improved dc-dc converter and an H-bridge. Using only one switch in the input section (the proposed dc-dc converter), not only reduces the cost and dimensions of the converter, but also minimizes the number of working modes (only two modes) and, as a result, simplifies its control. The presence of a common ground point in the input section is a feature that can eliminate the leakage current caused by solar cells in photovoltaic applications. Due to the continuity of the input current and the ability to increase the voltage in the proposed structure, it will be possible to track the maximum power point in the application of solar cells. It will be possible to control the effective value of the output voltage of the proposed structure by controlling the duty cycle of the switch of the input section. In this article, the proposed structure is introduced and additional explanations about its different operational modes are provided along with calculations related to loss and efficiency analysis. Also, a comparison between the proposed structure and a number of existing structures is presented. To prove the correct operation of the proposed converter as well as the correctness of theoretical calculations, simulation results extracted from PSCAD/EMTDC software are presented.