DROOP CONTROL STRATEGY USING RESONANT CONTROLLERS TO ACHIEVE RESISTIVE OUTPUT IMPEDANCE CHARACTERISTICS FOR UPS INVERTERS

ROBERTO CARBALLO; FERNANDO BOTTERON; GERMÁN G. OGGIER; GUILLERMO O. GARCÍA

Congreso; 14th Brazilian Power Electronics Conference (COBEP); 2017

A droop control strategy to achieve paralleloperation of single-phase inverters for UPS applications isproposed in this work. This strategy is based on multipleresonant controllers designed to comply with performancespecifications given by IEC62040-3. In order to reduce thecirculating current between the parallel connectedinverters, the inverters output impedances must beincreased. For this purpose a damping factor in theresonant controller tuned at the fundamental frequency isproposed. A design criteria for this damping factor isproposed based on a state-space model of the whole UPSsystem. Experimental results are presented to validate theproposal.