Motor frequency change servo controlling system

Abstract

A servo control system of frequency conversion for motor includes a squirrel-cage motor, a main loop part consisting of rectifying, filtering and contravariant circuits which are connected between the outer power supply and the squirrel-cage motor, a power supply part for providing power supply to the control main panel, and the control loop part integrating of chip in system grade, intelligent power module and output-input circuit. The system which uses AC squirrel-cage motor with three-phase in low cost, long service life and no requirement of permanent magnet as well as the intelligent control can control the position, rotary speed, accelerated speed and output torque of the motor in any size effectively through the programing.

Description

technical field [0001] The invention relates to a frequency conversion servo control system, in particular to a motor frequency conversion servo control system. Background technique [0002] With the rapid development of microelectronics technology and power semiconductor technology, frequency conversion technology has made great progress in AC asynchronous motors, which account for 85% of the total power load. As we all know, DC brushed servo motors and AC brushless servo motors occupy the mainstream position in the control field at present. [0003] The rotation of the DC brushed servo motor is a constant magnetic field generated by the permanent magnet on the stator side. After the rectification of the rotor, a current orthogonal to the stator magnetic field passes through the armature coil of the rotor to generate a turning force. This orthogonal relationship is automatically maintained by the brushes and the commutator, so the control is relatively simple. However, th...

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Problems solved by technology

However, there are the following problems: the brush motor needs frequent maintenance, cleaning, and replacement of brushes, which brings about high maintenance costs; the temperature rise or vibration of the motor will cause the permanent magnet to weaken or fall off, causing the output power of the motor to drop or even There are accidents involving personal safety; due to the weak magnetic field of the permanent magnet and the spark of the commutator, it is difficult to start directly from a static state; and due to the spark of the commutator, it cannot be used in some specific fields (such as explosion-proof) and it is difficult to speed up

Its principle is the same as that of the DC servo machine, so its control is more complicated than the above-mentioned DC machine, the control is difficult, and the cost is high. At the same time, there are problems of weakening or falling off of the permanent magnet caused by high temperature or vibration.

In addition, due to the weakening of the permanent magnet, the capacity of the motor is limited to a certain extent, and the centrifugal effect of the rotor limits the speed increase to a certain extent

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