Precompensated Master Slave Control of Parallel DC-DC Converter in DC-Microgrid

Abstract

DC microgrid comprises of various loads at various voltage levels, the load side demand is contributed by DC-DC converters based on the load requirement. A single DC-DC converter suffers a higher current stress when it powers all the loads connected on the system. So in order to reduce the current stress on the converter and to increase the efficiency of the system, paralleling of DC-DC converters is employed. For paralleled converters it is necessary to share the load current equally among the converters and to provide proper voltage regulation on the load side. Parallel DC-DC converters require a special current sharing mechanism to share the current equally. This paper proposes a modified Master Slave Current sharing mechanism to adjust the duty ratio of the converters' PWM signal. The slave converter follows the reference current generated by the master converter. Precompensation has been employed for the master-slave current for proper gain control and stability. This paper also discusses the dynamic response of the system for various loading conditions. The proposed work was simulated using Matlab / Simulink platform. The hardware was implemented using PIC18f458 microcontroller and the results were inferred to have better stability and proper voltage regulation on the load side converters.