A Single Switch Multiple Step Gain Converter for Solar PV Applications

In this writeup a new converter having multiple step-gain voltage output for solar PV applications is introduced. The proposed converter is an improved buck-boost converter and its voltage gain is expandable. The gain is higher when compared to conventional converters such as ordinary boost,ZETA, SEPIC and Cuk converters, for a specific duty ratio. This converter makes use of only one power switch. Also the voltage stress across it is low. As the converter has only single switch, it is easy to control, and implement MPPT(maximum power point tracking) to it, thereby providing maximum output of the most available renewable energy resource. Incremental Conductance MPPT control is used along with this converter for MPP tracking, desirable for solar PV applications. N level voltage output can be obtained from this same converter by repeatedly following the same topology. The converter is also capable of supplying power to the connected loads at all its port at various voltage levels. Ordinary switches are used to separate different volage levels. The operating principle and the mathematical analysis for voltage gain and output current of the proposed converter are discussed. Simulation results with InCond MPPT and converter hardware are presented to validate the designed converter and its working.