A New Transformerless Step-up Converter with Low Input Current Ripple for Photovoltaic System

In this paper, a step-up converter with very high voltage gain and low input current ripple for photovoltaic systems is presented. One of the main features of the converter is not using coupled- inductors and increasing gain by using switched-capacitors, so the volume and weight of the converter has been greatly reduced. The auxiliary circuit has provided zero voltage switching conditions for the main and auxiliary switches, and due to the low number of elements, the efficiency of the converter has been significantly improved. The input current ripple of the converter is very low, which makes it easy to track the maximum power point from the photovoltaic cells. Due to the increase in gain and decrease in voltage stress on the switches, it is possible to use switches with lower RDS(on), and conduction losses are subsequently reduced. Also, due to the complementary function of the switches, the design of the control circuit is simple and the control of the converter remains as PWM. The converter is simulated in PSPICE software with a power of 110 W and an output of 330 V, and finally a prototype is made of it, and the laboratory results confirm the simulation results.