Coupling peak absorption circuit at input end of motor

Abstract

The invention discloses a coupling peak absorption circuit at the input end of a motor, wherein the coupling peak absorption circuit is placed at the input end of the torque motor in a PWM (pulse width modulation) driving way and used for absorbing coupling peak voltage pulses at the input end of the motor. The absorption circuit comprises a voltage stabilizing circuit constituted by a plurality of capacitors connected in parallel and four fast recovery diodes, wherein the voltage stabilizing circuit is connected between a driving power supply and a power supply ground in parallel, the diodes are subjected to serial connection in pair and then connected at the two ends of the voltage stabilizing circuit, and the first and the second input ends of the motor are connected between the two diodes which are in series connection. The coupling peak absorption circuit disclosed by the invention is favorable for eliminating the impacts of the coupling peak voltage pulses at the end of the long-distance PWM driving motor on the reliability of the motor and simultaneously has the characteristics of low energy consumption, good compatibility, obvious wave absorption effect, low cost and the like.

Description

technical field [0001] The invention belongs to the field of motor control, and mainly relates to a motor input terminal coupling peak voltage pulse absorbing circuit, in particular to an absorbing circuit capable of suppressing the input terminal coupling peak voltage of a long-distance PWM driven motor. Background technique [0002] At present, the motor drive is mainly driven by PWM. The PWM driving method is to transmit a set of PWM carrier waves to the motor input terminal (see standard carrier waveform figure 1 ), drive the motor to rotate by controlling the duty cycle of the carrier. The PWM carrier mostly appears in the form of a square wave. [0003] In the design of the control system, it is often difficult to adopt an integrated design scheme for the drive control components and the motor, and in most cases they are connected by wires. When the connection line is too long, spikes will be coupled at the motor input (see figure 2 , the voltage waveform amplitud...

AI Technical Summary

Problems solved by technology

There are following problems in these two kinds of absorbing circuits: 1) system energy consumption increases

Since the current of the PWM fundamental wave is relatively large, the energy contained in its high-frequency component is much greater than the energy of the peak voltage, and the above filter circuit absorbs the high-frequency component of the PWM fundamental wave and the peak voltage pulse together, so the filter circuit will increase. High Frequency Energy Loss of Fundamental Wave

In addition, the filter circuit generates a lot of heat, and the power value of the resistor R in the filter circuit generally requires tens of watts to hundreds of watts, which is not good for the thermal effect design and energy consumption design of the instrument.

2) Filter circuit parameters are difficult to match

There are two reasons for this. One is that when the pulse width of the peak voltage is large, the corresponding main frequency is closer to the fundamental frequency, and the parameters cannot be configured; the other is that the filter parameter setting is related to the distribution parameters of the actual transmission cable. The transmission environment of the site is difficult to be completely consistent, and the adjusted parameters may not be suitable after the instrument is installed

3) It is difficult to completely eliminate the peak voltage pulse

This is due to the nature of the filter circuit, the filter circuit can only suppress the amplitude of the interference

The filtering quality of the second-order filter circuit is better, but the inductance L is added to the armature circuit, which will also affect the dynamic performance of the motor.

4) Higher implementation cost

Although inductors, resistors, and capacitors are commonly used devices, inductors involve large currents; resistors are high-power non-inductive resistors; capacitors require high frequency response and high withstand voltage; these devices usually need to be customized separately

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