An air conditioning device includes an alternating current (AC) bus, a direct current (DC) bus, a first AC/DC circuit, a first DC/AC circuit, and a backup power supply apparatus. The AC bus is connected to two power supplies through a switching circuit. The backup power supply apparatus is connected to the DC bus or the AC bus. The backup power supply apparatus provides electric energy for the DC bus or the AC bus when the two power supplies are switched or fail, so that the first air conditioning load is not powered off. The backup power supply apparatus may supply power to the load when the two power supplies are switched or fail.