It sounds like your dad has some kind of issues with anxiety. Or he's going through a really really rough time in his marriage and is taking it out on you.
My best advice is, shut down around him. Don't talk back to him, don't answer back to his accusations, don't defend yourself, just completely shut down when he starts yelling at you and making you write sentences. Just say okay in a weak way, and write them robotically. He doesn't want to listen to you, and defending yourself is just a pure waste of time and energy and gives him the feeling he's right.
Best wishes. Soon you'll be old enough to get out of the house. In the meanwhile, enjoy your successes and the sports you play, and the classes you excel in.
Best wishes.
I am sorry this does happen where teens and parents butt heads..maybe he has a lot of stress going on and he has chosen to use you as a scapegoat..how does your Mom deal with it when he yells at you for the small stuff you describe , have you told her how you feel and asked for some help to speak to him about it .? If your family members agree with you about the issues , you know its something he has to deal with .It may be a good idea to avoid any confrontations as they can be upsetting, what did the counselor think about it ?