Ranking of IEEE conf:
1. Springer based (LNCS)
2. Others:Madbase, SCOPUS, COPERNICUS

You should choose a conference with the highest database rank and also a conference that lets you register for more than 1 paper.
For example Biomed, koalalumpur is Springer based (7 days to its deadline) and lets you register for more than 1 (two) with the same fee .
China , Shanghai even let you 3 by only one registration but is now closed.