SU1390759A1 - Digital electric drive - Google Patents

Abstract

The invention relates to electrical engineering and can be used to regulate the speed of electric motors. The purpose of the invention is to increase the reliability of the electric drive. The electric drive contains a frequency divider 10, the input of which is connected to the output of the generator 7, and the output to the input of a controlled one-vibrator 9. &) The input of the controlled one-vibrator 9 is connected to the input of a pulse-pulse modulator 6. Feedback input over the current of the electric motor by shifting the moments of writing the code of the control signals relative to the reference pulses, eliminates the analog current feedback signal to digital converter, simplifies the digital electric drive and improves reliability. 3 il.

Description

so; about about

O1

with

1

The invention relates to electrical engineering and can be used in electric micro-EBM drives in a control loop.

The aim of the invention is to increase the reliability of the drive.

Fig „1 shows a diagram of the electric drive; FIG. 2 is a diagram of an Ip-pulsed modulator; in FIG. 3, time diagrams of the operation of the pulse-width modulus tor. a.

The digital electric drive contains an electric motor 1 connected to the output of a power amplifier 2, a rotational speed sensor 3, digital controller 4, a rotational speed setting device 5, a pulse-width modulator 6, a generator 7, a current sensor 8 connected to the output of the power amplifier 2, inputs which are connected to the output of the pulse-pulse modulator 6, the outputs of the digital controller 4 and the generator 7 are connected to the inputs of the pulse-width modulator 6, the inputs of the controller 4 are connected to the outputs of the sensor and the rotation frequency sensor 3 .

The electric drive also contains an uploaded mono vibrator 9, the control input of which is connected to the output of current sensor 8, a frequency divider 10, the input of which is connected to the output of the oscillator, and the pulse-width modulator 6 is equipped with a subtracting counter 11, the data input 1 | 1X which is connected to the output of the digital controller 4, the counting input is connected to the output of the generator 7, the synchronization input is connected to the output of the controlled single-vibrator, the start-up input of which is connected to the output of the 10 frequency divider, two circuits EXCLUSIVE ShZh 12 and 13, circuit 14 bum holders, inverse 15 and forward 16 triggers and two AND circuits whose outputs are - with the outputs of the Pulse Width Modulator 6, the output of the detracting counter 11 is connected to the input of the delay circuit 14 and the first inputs of the first EXCLUSIVE OR 12 and inverse trigger 15, the output of the delay circuit 14 is connected to the first € 1 and the inputs of the second circuit. ACCS: 1ZHI 13 and direct trigger 16. The output of the frequency divider is connected to the second inputs of the first 12 and second 13 circuits EXCLUSIVE OR and inverse 15 and direct 16 t-riggers, outputs of the first circuit ISKPYUCHAN) - SEE OR 12 and inverse trigger 15

connected to the inputs of the first circuit And 17, the outputs of the second circuit SKIPSYUPSCH OR 13 and the direct trigger 16 are connected to the inputs of the second circuit And 18. The positions in FIG. 3 reflect the operation of the corresponding circuit elements.

The digital drive works as follows.

The first input of the digital controller 4 with the variable speed setting device 5 receives information about the set frequency of rotation of the electric drive. The second input of the digital controller is 4 seconds. The transmitter 3 frequency of rotation enters a sequence of pulses with a frequency depending on the frequency of rotation of the electric drive.

Digital controller 4 measures the period, the phase shift of the pulses arriving at its second input, calculates the actual values of the parameters of the virus, compares them with the specified parameters, and generates a control signal for the value of N received in the form of a parallel n-bit binary code to the data input -impulsive module - iTopa 6 „

This code is rewritten in the subtracting counter 11 by the decay of the signal arriving at the synchronizing input of the pulse-width modulo 6 p. From the output of the controlled single-oscillator 9. At the same time, the start. (N + 1) -th bit of the subtracting counter 11 is set to state 1. A pulse signal with a frequency f | is continuously applied to the counting input of the downlink counter 11. from the output of generator 7, which changes the state of the subtracting counter 11.

At the output of the subtracting counter 11, which is the output of its highest (n - (- l) -ro discharge, a signal is generated, the decay moment of which is phase-shifted relative to the decay time of the signal at the sync input to Vapichin, K, -N .

 -. Pulses with a frequency f from the output of the generator and go also to the input

frequency divider 10 with a division factor of 2, at the output of which reference pulses with a period are formed

about

 ° f 7

The output signal from the frequency divider 10 is fed to the second input of the controlled one-shot 9, which is a logical one-shot with a variable pulse duration, depending on the input voltage. The duration of the pulses at the output of the controlled one-shot 9 depends on. the magnitude of the current communication signal supplied to its first input from current sensor 8. This duration is equal to

-2 - 1 - V, t 2H 5

where Ig is the magnitude of the current box motor 1;

t about 9P PERMANENT temporary

shift.

The coefficient K is chosen from the condition

m "" with That. K i, i g, LO.

From the output of the controlled single vibrator 9, the pulses arrive at the Sikhronizvaya input of the pulse-width modulator 6, the decay moments of these pulses are shifted in time relative to the front of the reference pulses arriving at the clock input of the pulse-width modulator 6, the total time shift of the decay moments the signal at the output of the subtracting counter 11 relative to the edge of the reference pulses is

t

i ° V t j-w.M 2 o L 2 - - “1

These signals are fed to the inputs of the first circuit, EXCLUSIVE OR 12, at the output of which a width-modulated signal with a period

 and a pulse duration equal to

() .N- - Vd / o This signal is fed to the input of the first circuit AND 17, to another input of which a signal is received, depending on the sign of the magnitude (KiN - - it) formed by the inverse trigger 15, which is D- trigger with inverse output, by recording the state of the output of the subtracting counter 11 at the time of the decay of the reference pulses arriving at

with

five

0

five

0 g about

its clock input, In case 7 O, the output of the inverse trigger 15 is logical O, and the output of the first circuit AND 17, which forms the first output of the pulse-width modulator 6, is out of signal. With 1: O, the output of the first phase of the pulse-width modulator 6 is formed at this output.

In order to form a second phase signal of a pulse width modulator 6, the output signal of the subtracting counter 1I is shifted by a delay circuit 14 equal to 2. In this case, the total time shift of the decay moments at the output of the delay circuit 14 relative to the edge of the reference pulses is

p + 0 - K ,, + K, N.

These signals are fed to the inputs of the second circuit EXCLUSIVE OR 13. The forward trigger 16, which is a D-trigger with direct output, generates a signal depending on the sign of the magnitude (k, N -, +,). The formation of the signal of the second phase at the second output of the wide and large modulator 6 occurs in the same way as the formation of the first phase o

The introduction of an additional time signal D is necessary to exclude the dead zone of the pulse-width modulator 6 at zero values N and 1 ". At the same time, the maximum value of the control signal should not exceed

N

Y-) / K,

0

five

From the output of the pulse-width modulator 6, the signals of the first and second phases are fed to the first and second inputs of the power amplifier 2, which is a bridge transistor circuit that regulates the voltage supplied to the core winding of the electric motor 1.

Thus, the pulse-width modulator 6 generates pulse-width signals depending on the magnitude of the control signal and the current feedback signal, with a constant period,

T

equal to -, while the maximum delay of the control signal and the current feedback signal in the pulse-width modulator 6 is T, the introduction of the current feedback of the core of the electric motor 1 by shifting the control signal code into the counter meter 11 relative to the reference pulses allows to exclude the analog current feedback to digital converter and thereby simplify the digital drive. At the same time, due to the presence of high-speed current feedback, the stability of the elect:) oprivode increases.

Claims (1)

Invention Formula A digital electric drive containing an electric motor connected to the output of the power amplifier, a sensor Motor speed and a current sensor connected to the output of the Power Amplifier, whose inputs are connected to the outputs of the pilot-pulse modulator, the digital controller inputs are connected to the outputs of the setpoint ; The sensor and the rotational speed sensor of the electric motor, characterized in that, in order to increase reliability, a frequency divider is additionally introduced in it, the input of which is connected to the generator output, a controlled one-shot control 0 five 0 5 o The input of which is connected to the output of the current sensor, and the starting input is connected to the output of the frequency divider and the clock input of the ip pulse modulator, the pulse width modulator is equipped with a reading counter, the data input of which is connected to the output of the digital controller, the counting input is connected to the output of the generator, and the synchronization input is connected to the output of a controlled one-shot, two TEMPERATURE OR OR circuits, a delay circuit, inverse and direct triggers, and two AND circuits whose outputs are pulse-width outputs modulator, the output of the detracting counter is connected to the input of the delay circuit and the first inputs of the first circuit EXCLUSIVE CEE OR and inverse trigger, the output of the circuit is in -. the holder is connected to the first inputs of the second EXCLUSIVE OR circuit and the forward trigger; the second inputs of the first and second EXCLUSIVE OR and inverse and forward trigger circuits are combined to form the clock input of the pulse-width modulator; the output of the first circuit is the EXCLUSIVE OR inverse trigger. the first circuit AND, the outputs of the second circuit EXCLUSIVE OR, and the direct trigger are connected to the inputs of the second circuit I. Fyg.2