Interleaved High Gain Bidirectional DC-DC Converter for Grid Integrated Solar PV Fed Telecommunication BTS Load

In this paper, an interleaved boost based high gain bidirectional DC-DC converter for grid integrated solar PV fed telecommunication BTS (Base Transceiver Stations) load is proposed. A solar PV system is preferred to operate at low voltage due to the safety issues and the reduced power output in a series connected PV modules. The battery backup and the DC load in the system are also at low DC voltage and hence a system with low voltage DC bus is proposed. The low voltage DC bus (48V) is interfaced to high voltage (400 V) DC bus using a high gain DC-DC converter. A Voltage Source Converter (VSC) is used to connect this to the single phase AC grid of 230V. For the reliable operation of telecommunication station, the power flow has to be bidirectional. A bidirectional high gain DC-DC converter for this application is proposed and it is analysed, the expression for voltage gain is derived and the operation is verified with a MATLAB Simulink based modeling and simulation for both forward and reverse power flow. It is found that the switches are operated with less stress, the current ripple at low voltage DC bus is less and a high gain for boost and buck operation and is verified.