Bring a big stockpot filled with water to a boil (If your electric pressure cooker pot is stovetop-safe, feel free to use that instead of dirtying another pot.) Add in the ribs and the wings. Return to boil, let cook for 5-8 minutes at a hard boil on high heat. Drain and discard the water. Rinse the ribs and wings with clean water, getting rid of any scum clinging to meat.
Following the manufacturer's directions, turn the electric pressure cooker to saute or brown, on high heat. Swirl in the cooking oil and add in the onions. Brown the onions, about 8 minutes. Take your time!
Add in the garlic and the ginger into the pot, then add ribs and wings. Fill pot with water up to the "MAX" line. Close lid of pressure cooker, set to cook on high pressure for 90 minutes.
After cooking, let pressure release naturally, or use a kitchen towel and tongs to manually release pressure, being very careful of splatters.
Strain broth with fine mesh strainer, discarding the solids. Skim any surface oils on the broth, if desired. Season broth with soy sauce or salt, to taste.