To test control performance of the present electronic expansion valve and real-time controller developed with MCU

the experimental research of refrigeration systems was performed in cool startup or cooling load variation under a steady operating conditions. These systems were individually assembled with three kinds of expansion valves: thermostatic

electric driven by the stepmotor and electromagnetic. Results show that compared with conventional thermostatic expansion valves

electronic expansion valves are more suitable to integral controller and superheat controlled by continuous devices is more stable than that controlled by discrete devices; the integral element promotes control quantity greatly. The present electronic expansion valve and controller are of high-performance and low-cost. Compared with similar products of foreign companies

their control effectiveness is also obvious.