1. Industry overview
Refrigeration equipment, mainly used for food refrigeration, various cargo refrigeration and cabin air conditioning equipment in summer. It is mainly composed of compressor, expansion valve, evaporator, condenser, accessories and pipelines. According to the working principle, it can be divided into compression refrigeration equipment, absorption refrigeration equipment, steam injection refrigeration equipment, heat pump refrigeration equipment and electrothermal refrigeration equipment. At present, the most common application is compression refrigeration equipment. The heat of the object and its surroundings is removed through the working cycle of the equipment, resulting in and maintaining a certain low temperature state.
The use of VFD control (variable compressor capacity control) for the compressor in the refrigeration equipment can make the refrigeration equipment always operate with high efficiency close to the design conditions for changes in the refrigeration load. Freezers are used for freezing and refrigerating food. Therefore, in the food industry, the use of refrigeration equipment is very popular, and the control of refrigeration equipment is increasingly using VFDs.
In the cooling process, the client uses the host computer to do PID operation feedback, realizing the speed regulation of the VFD, and controlling the speed of the motor to achieve high efficiency and energy saving for the entire operation system. For the transformation in the actual production process, The VFD itself can use the pressure sensor feedback signal to realize PID operation independently.
3. Electrical Schematic Diagram and Site Pictures:
A. After the installation of VFD, the compressor can be adjusted according to the air volume demand, which is a very economical operation state. The motor running frequency can be adjusted through the analog quantity change, so that it always runs under the effective demand condition, and the energy saving effect is remarkable. .
B. The automatic control of PID operation only needs to input the required cooling capacity, and the motor operation is completely automatically controlled, replacing the manual labor of the original operator to change the intake air volume of the valve, which meets the production needs more efficiently and safely.
C. After using the VFD, the air compressor starts from a low frequency, and its starting acceleration time can be adjusted to reduce
D. After using the VFD, the air compressor starts from a low frequency, and its starting acceleration time can be adjusted, thereby reducing the impact on the electrical components and mechanical components of the compressor during starting, avoiding the impact of high current at power frequency starting, and enhancing The reliability of the system extends the service life of the compressor.