SU1410256A1 - D.c. electric drive - Google Patents

Abstract

The invention relates to electrical engineering and m. used in automated electric drives to stabilize the frequency of rotation of DC motors. The purpose of the invention is to increase the accuracy of the drive. The drive contains a motor 1 with a rotational speed sensor 3. The required rotational speed is set by a generator of 5 clock pulses. A reversible counter 6 at the input of the counts counts the number of incoming pulses from the generator 5 through the shaper 4. The code of the reversible counter 6 is converted in block 11 of the code comparison to a pulse-width signal fed through the amplifier 2 to the engine control. The other input of block 11 receives a periodically increasing counter code 9. Both codes are continuously compared. In transient modes, by introducing the decoders 7, 8, it is possible to avoid overflow of the reversible counter 6, since the output of the decoder 7 (8) at the maximum (minimum) code of the reversible counter 6 creates a signal level, while the driver 4 (10) is locked until the counter code is reduced (increased) 6, 1 sludge. i

Description

Yu SP 0d

1.U

1 The invention relates to electrical engineering and can be used in automated electric drives for stabilizing the rotation frequency of DC motors.

The purpose of the invention is to increase the accuracy of the electric drive. I The drawing shows the structure of the | DC drive circuit.

I The electric drive contains an electric motor 1; the main winding is connected to the output of power amplifier 2. Sensor 3 of the rotational speed of the electric motor is connected to the first input of the short pulse voltage former 4, the second input of which is connected to the first code of the generator 5 clock pulses. Reversible counter 6 subtractive input connected to the output of the driver 4 short pulses. In addition, the drive contains two decoders 7, 8, the first of which is connected to the third input of the former 4 short pulses, and the counter 9, the input of which is connected to the third generator output 5 clock pulses, the second output connected to the second input of the second transformer 10 short pulses, the first input connected to the output of the second decoder 8. The output of the counter 9 is connected to the first input of the code comparison unit 11, the second input of which is connected to the output of the reversing counter 6 and the inputs of the first and second decoder tori. The output of the second shaper 10 short pulses is connected to the input of the addition of a reversible counter. The output of code comparison unit 11 is connected to the input of power amplifier 2.

The direct current drive operates as follows.

The required rotational speed of the engine 1 is set by the frequency from the second output of the clock pulse generator 5, supplied through the short pulse generator 10 to the addition input of the reversing counter 6. The code of the reversing counter 6 starts to increase rapidly. The conversion of the code of the reversible counter 6 into the duration of the pulse-width signal, fed through the power amplifier 2 to the motor control t, is carried out by the code comparison unit 11, one input of which

ten

0

five

five

0

five

0

five

0

five

A reversible counter code 6 is received, and another is a periodically increasing code from pulse counter 9. At the output of pulse counter 9, a code is formed that corresponds to the number of pulses continuously arriving at its input from the clock generator 5. When the pulse counter 9 is full, it is reset to the zero state, in which case its code changes from maximum value to zero, and the cycle repeats again.

The capacitance of the pulse counter 9 is chosen equal to the capacity of the reversible counter 6, in this case, with the maximum code value of the reversible counter 6, the inequality A B (A is the code of the reversible counter 6, B is the code of the pulse counter 9) for the whole period of the code information B This causes a high level to remain at the output of the code comparison unit 11 for the entire period and a constant connection of the engine 1 to the power supply network. When decreasing the code of the reversible counter 6, the inequality A B will be fulfilled only in part of the code information following period B, and therefore, at the output of the code comparison unit 11, a pulse signal is generated, the duration of which is proportional to the code of the reversible counter 6. Thus, by continuously comparing the current the values of codes A and B at the output of block 11 of the comparison of codes, a pulse-width signal is formed, the duration of which is proportional to the current code value of the reversible counter 6,

As a result of the addition by the reversing pulse counter 6, its code continuously increases, the pulse duration from the output of the code comparison unit 1.1 increases proportionally, and the engine 4 begins to accelerate. Feedback pulses with a frequency fgj, from the rotation frequency sensor 3, are fed to the input of a short pulse 4, at the output of which after the arrival of each frequency pulse fgj. one short pulse is formed that coincides in time with the pulse from the first output of the clock generator 5. Frequency pulses from the first and second outputs

The clock pulses 5 are shifted relative to each other, which eliminates the simultaneous appearance of the pulses of the frequencies fo and f at the inputs of the reversible counter 6. The pulses of the frequency fog are fed to the input of the subtraction of the reversible counter 6, which continuously compares the reference frequency f and the feedback frequency f . In the steady state, the equality fg fo is established (. And the code of the reversible counter 6 ke is changed. Therefore, the pulse duration from the output of the jj 11 code comparison block in the steady state is constant.

In transient modes in the system, the occurrence of such a mode is possible, when fо foe or f if f f, the maximum code can be written in the reversing counter 6. Under this condition, the output of the decoder 8 creates such an output level at which the short pulse shaper 10 is locked and the frequency pulses ft do not pass to the frequency addition input of the reversing counter 6, which eliminates its overflow and, therefore, the possibility of changing its code from maximum to minimum when the next pulse arrives, the frequency fo. The next frequency pulse f (3 reduces the value of the reversing code is the level at which the driver 4 is open and the rtpo again compares the frequencies fg and f. Thus, the main advantage of the electric drive is the high dynamic accuracy of the stabilization of the rotation frequency of the engine, which is achieved by that the duration 0 of the generated pulse-width signal is proportional to the current code value of the reversible counter, at which the reference frequency and the feedback frequency from the sensor sk are continuously compared orosti.

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Claims (1)

Invention Formula Electric drive DC In the case of 2Q containing an electric motor, the main winding of which is connected to the output of the power amplifier, the rotational speed sensor of the electric motor, the output connected to the first input of the short pulse generator, the second input of which is connected to the first output of the clock generator, a reversible counter, input the subtraction of which is connected to the output of the short pulse generator, and the counter, which differs in that, in order to increase the accuracy of the electric drive, a second form Tel of short pulses, two decoders and block 30 the counter 6, the output of the decoder 8 sets the level at which the short pulse shaper 10 is opened, and the frequencies f and f are further compared, If . A reverse counter 6 is recorded the minimum code at which the output of the decoder 7 appears such a level at which the formation of codes is blocked, the first driver of short pulses and the generator of clock pulses are equipped with third pins connected respectively to the output of the first decoder and the input of the counter , the output connected to the first input of the code comparison unit, the second input of which is connected to the output of the reversible counter and the inputs of the first and second 40 rover 4 short pulse, and the encoders, the output of the second decoder jj 410256 A level appears at which shaper 4 is open and the rtpo is again compared between frequencies fg and f. Thus, the main advantage of the electric drive is the high dynamic accuracy of the engine rotation frequency stabilization, which is achieved by the fact that the duration 0 of the pulse width signal generated is proportional to the current value of the reversible counter code, at which the reference frequency and feedback frequency from the speed sensor are continuously compared. . 25 2Q 2Q thirty A DC motor, Q containing an electric motor, the root winding of which is connected to the output of the power amplifier, a rotational speed sensor of the electric motor, an output connected to the first input of the short pulse generator, the second input of which is connected to the first output of the clock generator, a reversible counter, the read input of which is connected with the output of a short pulse shaper, and a counter, which is different in that, in order to increase the accuracy of the electric drive, a second shaper has been entered into it powerful pulses, two decoders and a code comparison unit, the first short pulse shaper and the clock generator are equipped with third terminals connected, respectively, to the output of the first decoder, and the counter input, an output connected to the first input of the code comparison unit, the second input of which is connected to the output reversible counter and the inputs of the first and second 0  decoders, the output of the second decoder the pulses of frequency f do not pass to the subtracting input of the reversible counter 6, which excludes a jump-like change of the code of the reversible counter from minimum to maximum. The next pulse of frequency f increases the value of the code of the reversible counter 6, - at the output of the decoder 7 the torus is connected to the first input of the short pulse shaper, the second input of which is connected to the second output of the clock generator, and the output to the input of the reversible counter, the output of the code comparison unit is connected to the input of the power amplifier.