Stability Analysis and Implementation of Interleaved Bidirectional Converter as a High Current Interface in LVDC Microgrid

The interleaved bidirectional DC-DC converter (IBDC) is a viable alternative to the traditional converters for high current applications. It offers significant advantages in several applications with improved efficiency and reduced size of filter components. This paper delineates the small-signal stability analysis of a two and three-phase IBDC as a high current interface in an LVDC microgrid using the state-space averaging technique. The stability analysis can be performed for any number of phases in an interleaved converter, similar to the demonstrated analysis for a dual-leg IBDC. An analytical model for the average current mode-controlled IBDC is developed using a small signal modelling approach. It investigates the relationship between the DC bus voltage, inductor current, and the control parameter (i.e. duty cycle). The controller is designed and simulated in MATLAB/Simulink for 2 kW IBDC. From the simulation results, it is evident that the designed controller effectively maintains DC bus voltage at 48 V during various load transitions. Moreover, the open-loop experimental validation of the IBDC is carried out in the developed test-bed using C2000 microcontroller. In future, the work can be extended for closed-loop performance improvement and experimental validation for bidirectional power flow operation typically in a 48 V LVDC microgrid for residential applications or future DC homes.