Bearing, photovoltaic support and photovoltaic power generation system

The embodiment of the invention discloses a bearing, a photovoltaic support and a photovoltaic power generation system. The bearing comprises a bearing shell and a bearing cover, wherein the bearing shell is provided with an electromagnet; an axially arranged communicating part and at least one limiting part are formed on the inner surface of the bearing outer ring; the bearing inner ring is arranged in the bearing outer ring in a relatively rotating manner; the sliding piece is arranged between the bearing outer ring and the bearing inner ring in a sliding mode in the axial direction, and relative rotation between the sliding piece and the bearing inner ring is limited; the sliding piece has magnetism and is driven by the magnetic force of the electromagnet to slide; at least one limiting structure is formed on the outer surface, facing the bearing outer ring, of the sliding part, and comprises a locking block which can elastically stretch in the radial direction; the locking piece slides along with the slid