A New Triswitching Double Duty High Voltage Gain Boost Converter for DC Nanogrid Application

Abstract

The Tri-switching Double Duty Converter (TSDDC) is a new non-isolated high gain DC-DC boost converter topology presented in this paper for 400V PV-based DC Nanogrid application. In a conventional DC nanogrid system, two DC-DC converter has been used, one for stepping up the voltage & the other for maximum power point tracking mechanism (MPPT). The proposed TSDCC can perform both operations in a single stage. The proposed converter has been controlled by two duty ratios ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\delta _{1}$</tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\delta _{2}$</tex-math></inline-formula> ) with the help of three switches. The highlighting feature of TSDDC are i) Controlled on two different duty cycles ii) High voltage gain at low duty ratio iii) Lower voltage stress on switches and diodes. The TSDDC is simulated for 500W power with 400V. The working of the converter is explained in detail for continuous conduction mode (CCM). In addition, design guideline and comparative study are also presented. Furthermore, a control scheme is implemented that controls MPPT(maximum power point tracking). A lab prototype of TSSDC was developed for 21V-400V, 400W and the switching frequency is 50kHZ. The proposed TSDDC converter's operating concept and controllability are verified by the simulation results.