Biting???

I have a 5 month old Shepherd/Samoyed cross he is a great puppy except when he gets excited then he barks and lunges, bites and nips. We have only had him for a month now and have recently started puppy training. I have read so many things online and tried the tips our trainer has given about how to stop this and nothing I have done seems to work. Anybody out there can give me more ideas on what to do. At the moment the only thing I can do is put him in his kennel for a few minutes. He does seem to be spending a lot of time in there and I know its not fair but am desperate.