Design ofModular Converters Survey andIntroduction toGeneric Approaches

Thispaperpresents a new approachbasedon converter networks usingelementary cells (ec). Itdeals with thebeginning ofresearch anddevelopment carried outonthe design ofthe"ec", therandomcommandandthemagnetic coupling amongtheelementary cells. Thispaperintroduces at first therecent workscarried outoninterleaved "ec"and powerelectronics converters (cvs) intonetworks: frombasic interleaving approaches, trying tominimize filter sizes upto highly coupledsolutions trying tooptimize sizes butalso current andvoltage levels. Inthenextsections ofthepaper, the modularapproach willbepresented. Thepaperpresents a studyshowing howarandommodecontrol isusedtosimplify theimplementation ofa generic "ec"intoanynetwork. Evaluating theoutputvoltage filtering criteria, we compare classical synchronous interleaved andrandommodecontrols. Then,thepaperfocuses onthedesign andthecharacterization oftheelementary cell andespecially onitsactive part. Thelast partofthepaperfocuses onmagnetic coupling forconverter coupling andfiltering. Experimental results underline the importance ofcoupling amongelementary cells andinside the corresponding "cvs"andan analytical studyofmagnetic coupling ispresented. An2n-windings transformer formedofn identical three-winding transformers isusedtoconnect the "ec"amongthem.Theaimsofthesestudies aretoimprove electrical management ofmodular"cvs"network without any constraints on themodularity and thegenericity ofthe approach.