Heat pump system and the control method thereof

A heat pump system comprising:

• a compressor with an air inlet and an air outlet;
• a heat storage heat exchanger, the pipeline connection of which is configured to be disconnectable from the heat pump system;
• an indoor heat exchanger and an outdoor heat exchanger;
• a plurality of throttling elements respectively arranged between any two of the indoor heat exchanger, the outdoor heat exchanger and the heat storage heat exchanger;
• and
• a first type four-way valve and a second type four-way valve, the ports of which are respectively connected to the air inlet and the air outlet of the compressor;
• wherein the unconnected ports of the first type four-way valve are respectively connected to the outdoor heat exchanger and the heat storage heat exchanger;
• and the unconnected ports of the second type four-way valve are respectively connected to the indoor heat exchanger and connected to the port connected to the air inlet through a capillary or on-off valve;
• wherein in a combined defrosting mode, the refrigerant dissipates heat from the indoor heat exchanger and the outdoor heat exchanger respectively, and absorbs heat from the heat storage heat exchanger.