Abstract: The invention provides a wireless charging system and a wireless charging apparatus for wirelessly charging a receiving device, and provides a method of controlling the wireless charging apparatus. The wireless charging apparatus comprises a power supply for providing a power voltage; a primary charging core; a switch module for changing the power voltage to an input voltage connected the power supply and the primary charging core so that the primary charging core has a primary current according to the power voltage supplied from the power supply; and a controller connected to the switch module and the primary charging core for measuring the primary current and for outputting a control signal for controlling the power voltage provided from the power supply.