Control method for brushed direct current motor of electric running machine

Abstract

The invention relates to a control method for a brushed direct current motor of an electric running machine. A voltage negative feedback current compensation speed adjustment system is constructed, namely a power electronic converter outputs to a sampling resistor Rs connected in series with an armature driving circuit of the brushed direct current motor; a current positive feedback signal Id is sampled on the sampling resistor Rs; armature end voltage Ud is sampled through a parallel resistor on an armature of the direct current motor; the polarity of the current positive feedback signal Id is consistent with that of a rotating speed demand signal Un and is opposite to that of a voltage negative feedback signal Ud; after the three signals are amplified through an amplifier, an output is connected with the power electronic converter; an output of the power electronic converter drives the direct current motor; a static characteristic equation of a system is obtained according to a structure constructed by the system; the load disturbance is compensated by adopting a current positive feedback, and the external influence such as voltage fluctuation of a power grid is eliminated by adopting a voltage negative feedback, and therefore, the current positive feedback and the voltage negative feedback are combined to ensure that the output of the brushed direct current motor can be reasonably adjusted along with the ceaseless change of the load of the running machine, so that the aim of avoiding the troubles in mounting and maintenance of a speed measurement device according to the performance of the rotating speed negative feedback is fulfilled.

Description

technical field [0001] The invention relates to a motor control technology, in particular to a control method for a brushed DC motor of an electric treadmill. Background technique [0002] When a person runs on a treadmill, sometimes one foot is on the running belt, and sometimes both feet are on the running belt at the same time, so the load torque is not a constant value. The open-loop control of the brushed DC motor has a limited speed range, which cannot meet the speed drop requirements of the treadmill under different loads. [0003] The closed-loop system of brushed DC motor adopting feedback control can change the armature voltage correspondingly with the change of load to compensate the change of armature circuit resistance voltage drop, and obtain much better steady-state characteristics than the open-loop speed control system. Feedback control is generally To achieve negative speed feedback, speed detection devices must be installed, such as tachogenerators, photo...

AI Technical Summary

Problems solved by technology

[0004] The present invention aims at the troublesome installation and maintenance of the brushed DC motor of the electric treadmill using negative feedback control of the rotational speed, and proposes a control method for the brushed DC motor of the electric treadmill. The system performance is close to the speed negative feedback system performance

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