Defrosting device, defrosting method and air conditioner provided with defrosting device

The invention discloses a defrosting device, a defrosting method and an air conditioner provided with the defrosting device. A way of a first defrosting pipe is additionally arranged on a conveying pipe between indoor and outdoor heat exchangers; one end of the first defrosting pipe is communicated with the outdoor heat exchanger, and the other end is communicated with a conveying pipe at the front end of a heating flow direction throttling element; and a first controlled valve is arranged on the first defrosting pipe. The device uses one part of refrigerant in an outlet of the indoor heat exchanger for defrosting without being stopped, so that the continuous heating can be realized, the energy is not wasted, and the defrosting can be realized by only using a small part of heat; high-temperature and high-pressure refrigerant in an outlet of a compressor still passes through the indoor heat exchanger preferentially to guarantee no drop of the indoor heating temperature; and when the heating quantity of the air conditioner is effectively guaranteed, the indoor comfort of the air conditioner is greatly enhanced to achieve the undesirable effect. The device can finish the defrosting action under the condition of no stop, and can effectively prevent the outdoor heat exchanger from being defrosted by defrosting when detecting the frost of the outdoor heat exchanger.