Prepare ribs by trimming off excess fat and rinsing to remove any bone shards. Place in a large, heavy duty storage bag.
In a medium bowl, combine soy sauce, water, vinegar, brown sugar, pepper, sesame oil, garlic, ginger, onion, and sesame seeds.
Pour sauce into bag with ribs. Seal and place in refrigerator. Marinate for 2 hours to overnight.
Add contents of the bag to pressure cooker. Top with shredded carrots.
Cook on high pressure for 6 minutes, then allow a 15 minute natural release.
Before serving, transfer the ribs to a foil-lined cookie sheet and broil for 5 minutes on each side.