In　order　to　break　from　the　status　que　that　the　mainstream　design　method　of　intelligent　controllers　for　contactors　is　one　for　one,　a　digital　controller　is　proposed,　which　can　be　applied　to　series　of　AC　contactors　without　adjustment　through　estimating　the　control　parameters　based　on　the　online　measurement　results　of　coil　impedance.　During　the　closure,　the　duty　is　constant　and　the　pull-in　consumption　is　reduced　by　the　electro-magnetic　interference　filter　with　a　capacitor-free　coil　drive　circuit.　When　contactors　are　in　closed　position,　the　closed-loop　control　parameters　are　designed　according　to　the　online　measurement　results.　During　the　opening,　the　voltage　of　coil　became　negative　so　that　the　coil　current　decrease　rapidly.　Series　of　double-E　type　AC　contactors　from　18A　to　170A　are　used　as　prototypes　to　experiment.　The　results　show　that　the　digital　controller　for　series　of　AC　contactors　performs　well.　©　2019　IEEE.