Sounds like the fan is trying to speed up according to the performance power settings, then locks up. You will probably need a new fan. The laptop will have to be send for service, or you could try to do that yourself if you feel adventurous. Sony makes things kinda difficult for laymen to do that themselves.
A temporary fix, in case I was right, would be to go to advanced power settings and make sure that the plugged-in setting is the same as the on-battery setting.
If need instructions how to do that hit us back.