Optimized auto-cascade refrigeration system and method

The invention discloses an optimized auto-cascade refrigeration system and method, and belongs to the technical field of auto-cascade refrigeration. The system comprises a compressor, a condenser, a gas-liquid separator, a filter, a high-temperature throttling device, a heat exchanger, a low-temperature throttling device and an evaporator which are connected in sequence; the high-temperature-stage throttling device is composed of an electromagnetic valve and a capillary tube, and a thermostatic expansion valve or an electronic expansion valve can also be directly adopted; and the high-temperature stage throttling device is also connected with a temperature controller. According to the method, temperature signals at the tail end of the high-temperature-level throttling device and an inlet of the heat exchanger are collected through the temperature controller, the temperature signals are compared, and opening and closing of the high-temperature-level throttling device are controlled. According to the system, th