Using the frequency converter to control the speed of the screw pump can effectively save energy and improve the controllability of the screw pump. However, when determining the motor capacity and selecting the inverter for the on-site screw pump, the capacity of the motor and the type of inverter should be reasonably determined according to the actual situation to achieve the best cost performance.
Functional application of screw pump inverter
1. Instantaneous low voltage compensation function. In the variable frequency operation, the input voltage – once a power failure or instantaneous low voltage occurs, the inverter will trip due to instantaneous Undervoltage, so it cannot maintain continuous operation. With the low voltage compensation function, the duration of operation can be further extended. The so-called low voltage compensation function is to detect the drop in the output voltage and reduce the output frequency of the inverter before the alarm trips, and the inverter absorbs the regenerative energy generated by the motor so that the running time can last longer.
2. PID control function. The PID control function is based on the constant V/f control. The analog signal is used as a feedback signal, which is input into the inverter, and the deviation between it and the frequency command of the inverter is compared, and then the P (proportion), I ( Integral), D (derivative) control, so that the action of the load side can follow the command value. Therefore, when the load on the load side changes and the rotation speed drops, which affects the normal operation of the motor, the analog feedback signal obtained by the speed sensor is used to perform PID control through a closed loop, so that even if the load changes, the command value can be followed at any time to ensure operation. stability.
3. No impact start function. When the motor is idling, if the inverter starts suddenly, sometimes there will be excessive current and cause tripping. After using this function, the speed and direction of rotation of the motor can be searched, so as to achieve a shock-free start which was not possible in the past. In the submersible screw pump oil production system, even if the motor reverses under the action of the oil pressure head of the oil pipe, it can be stopped smoothly and then controlled to rotate in the original direction.