A speed difference control system of dual frequency converter and its control method

Abstract

The invention discloses a differential control system of double-frequency-converter, which comprises the following parts: host motor, accessory motor, host converter and accessory converter, wherein the power of host motor is supplied by 380V power after connecting DC power after communicating host motor and DC bus of the accessory motor; the accessory motor doesn' t connect 380V power, which adopts DC power after communicating the host motor as starting power. The modulating method of constant torque comprises the following steps: using comparator, PID adjuster, feed pump converter, feed screw pump and centrifuger and torque sensor to form the seal adjusting control system; adjusting the feed quantity of screw pump according to the PID output signal; realizing the modulation of constant torque. The modulating method of constant differential speed comprises the following steps: adopting comparator, PID adjuster, accessory motor converter, accessory motor and centrifuger and speed measuring device to form PID adjusting control system; adjusting the frequency of accessory converter of centrifuger according to specific PID control regulation; realizing the modulation of constant differential speed.

Description

technical field [0001] The invention relates to a dual frequency converter differential speed control system and a control method, belonging to the technical field of motor frequency conversion control. technical background [0002] Dual frequency converter differential speed control is an important form of differential speed control for decanter centrifuges. Although this control method can overcome the cumbersome pulley replacement required by traditional mechanical differentials to achieve differential speed control. [0003] However, in actual use, it is found that the dual frequency converter differential regulator still has the following two problems in use: [0004] First, the differential speed regulator of the dual frequency converter must solve the energy feedback problem of the auxiliary machine during braking, otherwise the frequency converter will alarm and stop soon due to the continuous increase of the pump voltage. Of course, the method to solve this problem...

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Problems solved by technology

It is also very important to maintain a certain differential speed when the centrifuge is running. The setting of the differential speed should be appropriate. If the differential speed is too large, although the processing capacity can be increased, the dryness of the separated matter cannot be guaranteed. If the differential speed is too small, the dryness of the separated matter cannot be guaranteed. It has been improved, but it is easy to block the machine and reduce the processing capacity; in addition, when the concentration of the centrifuge separator increases, the differential speed of the centrifuge will decrease due to the change of the load, which will also cause a blockage accident

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