Finally, {HEAD ~ several power converters} convert {TAIL ~ the intermediate voltage} to the desired working voltages 
convert
Finally , { HEAD ~ several power converters } convert { TAIL ~ the intermediate voltage } to the desired working voltages
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH