Experimental Investigation of a Digitally Current Controlled Synchronous Buck DC/DC Converter for Microgrids Applications

This paper investigates the synchronous buck DC/DC converter behavior, operating as a regulated current source (under peak current mode control) in the context of low voltage DC (LVDC) microgrids applications. A digital implementation scheme of the proposed control method is presented, based on TMS320F28027 microcontroller unit. The benefits of using peak current control, such as the constant switching frequency and the accommodation of synchronous rectification operation, are pointed out. A prototype converter is designed and constructed in order to validate the discussed approach and experimental results are presented, indicating the efficiency improvement that can be achieved due to the synchronous rectification mode. Moreover, the incorporation of the current controlled synchronous buck converter in a 28 V DC bus (which is a standard voltage level for on-board DC microgrids of aircraft electric systems) as well as its dynamic behavior are experimentally examined, through various transients and step changes. In this way, the present work becomes the basis for improving the synchronous buck converter operational behavior, in LVDC microgrids with regulated DC voltage buses.