SU782112A1 - Rotational speed regulator for dc micromotor - Google Patents

Description

Union of Soviet Socialist Republics

State Committee

USSR in matters of inventions and discoveries

ABOUT ^ XW-E OF THE INVENTION

TO AUTHOR'S CERTIFICATE (61) Additional to author. certificate-wu - (22) 3 announced on 12/27/78 (21) 2703303 / 24-07 with the addition of application No. - (23) Priority -

Published on 11/23/80. Bulletin No. 43

Date of publication of the description 27.111.80 "7821'12 (51) M. Cl

H 02 P 5/06 (53) UDC621.316.

.718.5 (088.8)

(72) The inventors

V.O. Vyazemsky and V. Yu. Sukhodolsky (71) Applicant - · - ^; .

Leningrad <? Renden Lenin Electrotechnical Institute named after V.I. Ulyanov (Lenin) / 54) ROTATION FREQUENCY REGULATOR FOR DC MICROELECTRIC MOTOR

I -

The invention relates to electrical engineering, in particular to an automated electric drive, and can be used in low-power low-speed electric drive systems.

Known speed controller ^{5 of a} DC motor containing an operational amplifier, a voltage reference>

Closest to the invention in technical essence is a device ¹⁰ comprising an operational amplifier, a voltage reference source, first and second controlled keys connected to a pulse control circuit [2 ^. _J5

The disadvantage of these regulators is-! unstable operation at low values of the adjustable speed of about 50-200 rpm. The main reason for such a low frequency _meters minute rotation, the value of counter electromotive force of the armature - of the order of tens of millivolts, difficulty of isolation consideration way - by compensating with the help of the bridge circuit the voltage drop across the ohmic resistance of the armature and the resistance of the brush collector transition. The latter component at low rotational speeds has the largest value compared to the others, and, including the significant noise component, which changes with time as the collector sections and brushes wear out, practically cannot be compensated.

11el of the invention - the expansion of the range of regulation of the frequency of rotation of the electric motor.

The goal is achieved in that the input of the first key is connected to the output of the operational amplifier, the output is connected to the motor collector and the input of the second key, the output of which is connected to the inverting input of the operational amplifier, and the non-inverting input of the operational amplifier is connected to a reference voltage source.

In FIG. 1 is a block diagram of a controller; FIG. 2 - time diagrams .X-gY:

> · We stress at various points in the regulator circuit.

The controller contains an operational amplifier 1, a first key 2, a motor 3, a second key 4, a voltage reference 5 and a pulse control circuit 6.

The pulses from the output of the control circuit 6 (Fig. 2a) unlock the first key. On its output, power pulses of the electric motor are formed, the amplitude of which changes under the action of the control signal at the output of the operational amplifier 1 so that the rotational speed of the electric motor is kept constant (Fig. 2c) .

In the pause between the power pulses at the end of the transient pulse from the output switch 2 circuit 6 controlled singing _w (FIG. 26) opens the second switch 4, whereby the motor armature through a low resistance to open the key 4 is connected to the inverting input of the operational amplifier 1 , and in _and 'the auto-regulation loop is fed against the EMF of the armature, which is directly proportional to the rotation frequency (Fig. 2 c, d). Since the current through the armature winding and the collector while offline and soprotivpenie input of the operational amplifier 1 is many times greater than the resistance of the armature and the brush collector transition, the input voltage to the operational amplifier 1 is no component of the voltage drop in the ohmic soprotivpe- SRI armature ³⁵ and the brush transition resistance collector, therefore ^ no compensation is required.

If an integral chopper is used as a switch on two transistors switched on opposite, the contact potential differences of the saturated transistors are mutually compensated, and the residual voltage on the open key, summing up against the armature EMF, is negligible. At the moments when the key 4 is closed, and a power pulse is supplied to the engine 3 from the output of the key 2, the high resistance of the private key 4 reliably protects the input of the operational amplifier 1 from overload.

In the input stage of the operating circuit 1 output voltage of the key 46q | is compared with the reference voltage (Fig. 2 g), which sets the required frequency of rotation of the electric motor, the error signal is amplified and fed to the input of the key 2, determining the amplitude of the power supply pulses of the electric motor, and therefore its rotational speed. The rectangle shape of the power supply pulses of the electric motor is provided by the correction circuit included in the operational amplifier.

The use of the armature measured in pauses between the power pulses of the electric motor against the EMF as a negative feedback signal in the autoregulation circuit eliminates the need to compensate for the voltage drop across the ohmic resistance of the armature and the resistance of the collector brush transition. This allows you to expand the range of regulation in the direction of low speeds. The controller entering stabilization mode does not depend on the gain of the operational amplifier; therefore, no tuning elements are required.

V.

Claims (2)

3 we are voltages at various points in the regulator circuit. The controller contains operational amplification 1, the first switch 2, the motor 3, the second switch 4, the source 5 of the reference voltage and the pulse control circuit 6. The pulses from the output of the control circuit 6 (Fig. 2a) unlock the first key 2 and the motor power pulses are generated at its output, the amplitude of kfbpijx is changed by the action of the yT11 signal at the output of the operational amplifier 1 in such a way that the rotation frequency of the motor is kept constant (Fig . 2c). In the pause between the power pulses, at the end of the overshoot process, the pulse from the output of the key 2 of the control circuit 6 (Fig. 26) unlocks the second key 4, as a result of which the electric motor through a small resistance of the public key 4 is connected to the inverting input of the second amplifier 1, and the contour of Shrovani’s authors is supplied by the counter-EMF of the core, dir1 о o, and proportional to the frequency of rotation (Fig. 2c, d). Since the current through the winding of the core and the collector is absent, and the input resistance of the amplifier 1 of amplifier 1 is many times greater than the resistance to the collector and brush nepexioioa of the collector, there is no drop in the voltage of ohmic resistance and resistance in the voltage at the input of the operative force of the bodies 1 brush collector junction, there is no need for their coupling factor. In the case of using as the key 4 of the integrated preproced np of two oppositely connected circuits, the flow of saturated transistors is compensated for, and the residual voltage on the open key, summing up with the EMF court, turns out to be a failure. At the same time, the key 4 is closed, and the motor 3 is supplied with an impulse from the output of the key 2, the high resistance of the private key 4 reliably protects the input of the operating device 1 from overload. 24 In the input stage of operating voltage 1, the output voltage of the 4CQi key is compared with the reference voltage (Fig. 2g), which sets the required rotation frequency of the electric motor, the error signal is amplified and fed to the input of the key 2, the amplitude of the power supply impulses of the electric motor is determined, and therefore, and its rotational speed. Directly on the shape of the electric motor supply pulses is provided by the correction circuit included in the operation of the amplifier. The measurement measured in the pauses Between the power supply pulses of the electric motor and the counter-emf of the core as a negative feedback signal in the Autocontrol circuit, eliminates the need for compensation of the voltage drop across the ohmic core resistance and the resistance of the brush collector junction. This allows a wider range. Adjustable to low speeds. The inclusion of the regulator in the stabilization mode does not depend on the gain of the operational amplifier; therefore, no trimming elements are required. Formula of frequency control Regulator of rotational speed for a microelectric motor of direct current, containing an operational amplifier, reference voltage suppressor, first and second controlled keys connected to a pulse control circuit, characterized in that in order to extend the range of regulation , the input of the first key is connected to the output of the online amplifier, the output is from. the collector of the electric motor and the input of the second switch, the output of which is connected to the inverting input of the operational amplifier, and non-inverting; the input of the operational amplifier is connected to the source of the reference voltage. Sources of information taken into account in the examination 1. USSR author's certificate number 598204, cl. H 02 P 5 / O6, 1978. 2. The patent of Germany No. 2224662, kp. H 02 R 5/06, 1975. SiS --- S -Fi-i - t; - - - -; fc up; b i-j -: - :. a d Chop