Heat pump system capable of heating and defrosting simultaneously

The heat pump system comprises a gas-liquid separator and a compressor, an outlet of the compressor is provided with a heating main path and a defrosting branch in parallel, the other end of the heating main path and the other end of the defrosting branch are each connected with a first-stage liquid distribution head, the first-stage liquid distribution head is connected with N second-stage liquid distribution heads, and the N second-stage liquid distribution heads are respectively connected with N first-stage liquid distribution heads and N second-stage liquid distribution heads. Each secondary liquid separation head is connected with an outdoor heat exchanger, and an outlet of each outdoor heat exchanger is communicated with the gas-liquid separator; a temperature sensor is used in the system to detect the real-time temperature of the outdoor heat exchangers at any time and feed back the real-time temperature to the system, and the defrosting mode and the heating mode distributed to each outdoor heat exchan