How big is the raised planter. If it's a big one yes but put them in the middle of the planter and mulch them with dry leaves after the ground is frozen a bit. You do it then so mice, voles and little critters don't get in there and make a winter nest and feed on your plants all winter. If you wait until the round is frozen a bit they will have already gone elsewhere.

Back to the planter. The trouble with over wintering in a planter or pot is the freeze thaw cycle and that kills plants. The sun warms the outside and it thaws a bit then freezes at night. You want the ground to remain frozen.

And there-in lies your answer-- if the bed is big enough that the ground around the plants will stay frozen then go ahead. The mulch will help keep it frozen and protect the roots too