I. Overview:

 

In recent years, with the development of society and the improvement of people's living standards, the continuous development of urban construction, the concentration of urban populations, the rapid increase of industrial and domestic water use, and the shortage of urban water supply have become increasingly prominent. Traditional irrigation methods can no longer meet the requirements of modern irrigation, and it is imperative to adopt efficient irrigation methods. Only automatic control methods can meet the requirements of modern irrigation. This article introduces the application of easy drive ED3100 series frequency converter in farmland irrigation system.

 

2. Irrigation system

 

Irrigation systems are divided into sprinkler irrigation systems, drip irrigation systems, and low-pressure pipeline water delivery irrigation systems. They are mainly composed of three parts: the first water intake and pressurization facility, the water delivery pipe network and the irrigation water outlet device. The pipeline irrigation system is usually divided into three parts according to its mobility. There are three types: fixed, semi-fixed and mobile. Pipeline irrigation system has the advantages of saving irrigation water, reducing channel occupation, improving irrigation efficiency and irrigation water quality, etc. It has become the direction of technological transformation in water-lifting irrigation areas and well irrigation areas. The farmland water-saving irrigation system adopts the principle of adapting measures to local conditions. According to the different needs of different regions and different crops, different irrigation facilities are selected, and advanced technologies such as computers, frequency converters, sensors and other advanced technologies are used to monitor and manage farmland irrigation to ensure timely and appropriate satisfaction. The water needed for crop growth can achieve the purpose of water-saving irrigation and water-saving irrigation automation.

 

3. Easy-drive frequency converter used in irrigation system

 

Easy drive inverter adopts advanced SPWM technology, built-in PID function, and carries the water pump of the pipe network. Through the pressure sensor installed on the pipe network, the water pressure is converted into an analog signal of 0-10v to adjust the speed of the pump motor. When the user's water consumption increases and the pipe network pressure is lower than the set pressure, the output frequency of the variable frequency speed regulation will increase, the speed of the water pump will increase, and the water supply will increase. When the set pressure is reached, the frequency reduction motor speed of the inverter will decrease. , Make the pressure of the pipe network constant at the set pressure; when the water is not used for a long time, the inverter enters the sleep state and the water pump stops working, and vice versa. In this way, the closed-loop PID control not only achieves the purpose of constant pressure water supply, but also reduces manual operation, saves water and electricity.

 

Compared with other water supply methods, the easy drive ED3100 variable frequency constant pressure water supply system has the following advantages in addition to significant energy saving effects:

 

1. The constant pressure water supply technology adopts a frequency converter to change the frequency of the motor power supply, and adjusts the speed of the pump to change the outlet pressure of the pump. Compared with the method of controlling the outlet pressure of the pump by adjusting the valve, it has the effect of reducing pipeline resistance and greatly reducing the interception loss.

 

2. As the water pump works under variable frequency conditions, when its outlet flow is less than the rated flow, the pump speed is reduced, which reduces the wear and heat of the bearings and prolongs the mechanical life of the pump and the motor.

 

3. The water pump motor adopts the soft start method and accelerates according to the set acceleration time to avoid the impact of the current when the motor starts and the influence of the fluctuation of the grid voltage. At the same time, it also avoids the vibration of the pump system caused by the sudden acceleration of the motor and eliminates the water hammer phenomenon. .

 

4. Realizes constant pressure automatic control, does not require frequent operation by operators, reduces the labor intensity of personnel, and saves manpower.

 

4. Application site: