Frequency conversion controller of motor

Abstract

The invention provides a frequency conversion controller of a motor, which comprises a power supply module, an optoelectronic isolation module, a control module and a two-phase three-leg inverter module, wherein the power supply module is connected with the control module, the control module is connected with the two-phase three-leg inverter module, the two-phase three-leg inverter module outputs three phases of power supplies to be connected to an external unidirectional asynchronous motor, the control module is also connected with the optoelectronic isolation module, and the optoelectronic isolation module is provided with a pulse signal input end, a direction signal input end and an enable signal input end. According to the product, the traditional control method of utilizing a silicon controlled rectifier to control the conduction angle and regulating the voltage is replaced by the control method of frequency conversion, the unidirectional asynchronous motor serves as a two-phase motor, and a starting winding serves as a one-phase running winding, the two-phase three-leg SVPWM (space vector pulse width modulation) combined with V / F (voltage / frequency) variable frequency control on the two-phase motor is realized, so that the control over the unidirectional asynchronous motor is perfected, and the requirement that the knitted piece pulling of a flat knitting machine is not influenced by the external power supply is met.

Description

technical field [0001] The invention relates to the field of textile equipment control, in particular to a motor frequency conversion controller specially used for bottom lifting motors and roller motors of computerized flat knitting machines. Background technique [0002] At present, the pulling of the fabric pieces of the computerized flat knitting machine needs to use the roller motor and the bottom lifting motor to participate in the completion. The roller motor and the bottom lifting motor are actually a single-phase asynchronous torque motor. In the computerized flat knitting machine The motor is required to maintain a constant torque during the pulling process of the fabric. The control method of the torque controller of the traditional roller motor and the lifting motor is to control the conduction angle of the AC power supply through the thyristor, and complete it through voltage regulation. However, due to grid voltage instability or poor AC power quality, it is d...

AI Technical Summary

Problems solved by technology

However, due to grid voltage instability or poor AC power quality, it is difficult to ensure constant torque traction by using the traditional conduction angle control voltage regulation method, that is, it is difficult to smoothly adjust the output voltage

Once the average effective voltage output by the frequency conversion controller of the motor is slightly high, it will cause the fabric to be pulled too quickly, which is easy to damage the fabric; and if the average effective voltage is slightly low, the fabric will be pulled slowly, which will easily lead to fabric stagnation

Therefore, the existing motor frequency conversion controller often needs to be manually adjusted during use, and needs to be readjusted from time to time as the external voltage changes, which brings a lot of inconvenience to the users of the computerized flat knitting machine

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