| Air compressors are widely used in machinery manufacturing, automatic production lines, glass, ceramics, clothing, toys, plastics, and many other industries. Generally, the factory has a 10-30% allowance for the air compressor in the design. In addition, the actual demand of the factory has seasonal and temporal fluctuations, which also leads to large fluctuations in gas consumption. Therefore, the air compressor does not operate at full load most of the time, and there is a lot of room for energy saving. Traditional air compressors also have many problems, mainly as follows: 1. High power frequency starting impulse current; Although the main motor adopts y- △ reduced voltage starting or reduced voltage starting, the starting current is still large and has a great impact on the power grid, which is easy to cause instability of the power grid and threaten the operation safety of other electrical equipment. For self generating plants, several times of the rated current impact may also lead to other equipment abnormalities; 2. Power consumption during loading and unloading; After the pressure reaches the required working pressure, the traditional control method determines that the pressure will continue to rise until the unloading pressure. In the process of pressurization, more heat and noise will be generated, resulting in power loss. On the other hand, before the high-pressure gas enters the pneumatic components, its pressure needs to be reduced by the pressure reducing valve, which also consumes energy. When the unloading pressure is reached, the air compressor automatically opens the unloading valve to make the motor idle, causing serious energy waste. The power consumption of the air compressor during unloading accounts for about 30% - 50% of the full load. It can be seen that the traditional air compressor has obvious energy-saving space. 3. Unstable pressure and low degree of automation; The traditional air compressor has a low degree of automation, and the output pressure is adjusted by controlling the loading and unloading valve and regulating valve. The adjustment speed is slow, the fluctuation is large, the accuracy is low, and the output pressure is unstable. 4. Large amount of equipment maintenance; The power frequency starting current of the air compressor is large, up to 5~8 times the rated current. The working mode determines that the loading and unloading valve must act repeatedly, the components are easy to age, the power frequency high-speed operation, the bearing wear is large, and the amount of equipment maintenance is large. Using frequency converter to transform the air compressor has obvious advantages and convenient transformation. The frequency conversion control system of air compressor is composed of frequency converter, pressure sensor and control indication circuit The working process is to use the pressure sensor device to detect the pressure of the pipe network, and the detection and display instrument transmits the analog signal reflecting the output pressure to the frequency converter. The frequency converter compares the feedback signal with the set signal, and uses the PID inside the frequency converter to automatically adjust the output frequency, so as to automatically adjust the speed and output power of the compression motor, forming a closed-loop feedback system to maintain the constant and automatic control of the pressure of the pipe network. The main advantages of using frequency converter transformation are as follows: 1. The starting current is small and has no impact on the power grid; When the frequency converter starts the motor, the current rises gently and has little impact on the power grid; 2. Stable output pressure; After adopting the frequency conversion control system, the pressure of the gas in the gas supply pipeline can be monitored in real time, so that the pressure of the gas in the gas supply pipeline remains constant, and the production efficiency and product quality can be improved; 3. Small amount of equipment maintenance; Due to the soft start of the frequency converter on the air compressor, the impact on the equipment is small. Because it can automatically reduce the frequency, the loading and unloading valve does not need to act repeatedly, the bearing wear is small, the service life of the equipment is extended, and the amount of maintenance work is reduced; 4. Energy saving; The air compressor basically belongs to constant torque load, and the motor speed can be adjusted by frequency conversion speed regulation according to the air supply volume, so that the output power of the motor is basically proportional to the speed (air supply volume). When the air consumption is reduced, the pressure at the exhaust port rises, which is fed back to the frequency converter through the closed loop, so that the motor speed is reduced and the shaft output power is reduced; When the air consumption increases, the pressure at the exhaust port decreases, which is fed back to the frequency converter through the closed loop, so that the motor speed increases and the shaft output power increases. Therefore, through the pressure closed loop, the variable frequency air compressor system can track the load change of the air supply system in real time, adjust the speed of the air compressor motor, ensure the constant pressure at the exhaust port, and make the compressor motor work in the most economical operation state. It avoids the frequent loading and unloading of the air compressor in the original control mode, and frequent startup and shutdown, which greatly reduces the electric energy absorbed from the power grid. 5. Provide strong and sensitive software / hardware current limiting protection, overcurrent and overvoltage protection, short circuit protection to ground, overload protection, short circuit protection of IGBT, abnormal current detection, abnormal relay pickup and other protection functions to ensure the stability and reliability of the air compressor system. Parameter setting Specific instructions (set according to actual needs) F0.02＝1 Start and stop of external terminal F0.03＝8 PID closed loop is valid F0.17＝XX Acceleration time (set according to actual demand) F0.18＝XX Deceleration time (set according to actual demand) F4.00＝1 X1 is defined as closed forward running （F4.13＝2） When Ai1 signal is 4 ~ 20mA, it corresponds to 4mA value. If it is 0 ~ 10V, this parameter does not need to be set F A.00＝0 The given source of PID is f a.01, and the size is set by F a.04 F A.01＝XX Set the demand pressure in 0.01Mpa. It can also be modified by pressing the up and down keys on the keyboard F A.02＝0 PID feedback channel is Ai1 F A.04＝1.0 Range of remote pressure gauge, unit: MPa; 1MPa = 10ba (kg) In short, after adopting the variable frequency constant pressure control system, it can not only save a considerable amount of power costs, prolong the service life of the compressor, but also achieve the purpose of constant pressure gas supply, and improve production efficiency and product quality. | |||||||
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