SU989721A1 - Dc electric drive - Google Patents

Description

The invention relates to electrical engineering and can be used in devices for stabilizing the speed of rotation of tape drives.

Known speed controllers ⁵ rotations of DC motors ^ containing a speed sensor, an amplifier-driver and a generator of the driving frequency, supplying the _10th motor with a constant voltage, changing with various external influences [1].

However, when operating the actuator at low speeds inscribed ki- ₁₅ kinetic energy of it is small, and the voltage applied to the motor armature, is comparable with the open circuit voltage, which greatly reduces engine acceleration. In connection with this, any change in the load moment on the motor shaft leads to significantly larger changes in the rotational speed than when operating at speeds close to the nominal

Closest to the invention is a direct current electric drive containing an electric motor, the anchor winding of which is connected to a power key, a rotational speed sensor rigidly connected to the electric motor shaft, and an output connected to a sensor signal amplifier, a reference frequency generator 12 J,

However, the known DC electric drive does not provide a wide range of speed control, since it requires additional flywheel masses at low rotational speeds, which provides a slight increase in uniformity and accuracy, but significantly reduces dynamic characteristics, delays transient processes, and creates large loads in the conditions of support nodes and, as a result, reduces the life of the product as a whole.

The purpose of the invention is the expansion of the range of rotation speed regulation and the improvement of dynamic characteristics.

This goal is achieved by the fact that two counters, four adders, two ren 10 histras, a code dial, a quantization and control unit, the first and second valves, a control signal valve and three code control units are additionally introduced into the DC drive, while the output of the reference generator frequency through 15 the first gate is connected to the counting input of the first counter, the input R of which through the quantization and control unit is connected to the output of the amplifier of the sensor signal, the outputs of the bits 20 of the first counter are connected to the first inputs of Vågå adder, the second inputs of which are connected to the outputs of the set point code bits, the outputs of the first adder are connected to inputs 25 of the first register and the first code control unit, a timing input of the first register is connected to one of the quantizer outputs and control outputs of the first register are connected to the ₃₀ first inputs the second and third adders, the output of the third adder is connected to the inputs of the third code control unit and to the inputs of the second register, the clock input of which through the second valve is connected to the third output of the block quantization and control, and the outputs of the bits of the second register are connected to the second inputs of the third and second adders, the outputs of the second adder are connected to the first inputs of the fourth adder and to the inputs of the second code control unit, the second inputs of the fourth adder are connected to the outputs of the discharges of the second counter, the counting input of which is connected with the second output of the reference frequency generator, the third output of which is connected to one of the inputs of the quantization and control unit, the output of the fourth adder and ⁵⁰ outputs of the first, second and third of the code control units are connected to the corresponding inputs of the control signal valve, the output of which is connected to the input of the key element ^{55 of the} power supply of the motor armature winding, and the third outputs of the first and third code control units are connected respectively to the inputs of the first and second valves, respectively.

The drawing shows the functional. DC electric drive circuit.

The direct current electric drive comprises a direct current electric motor 1, a key element 2 for supplying the armature of the armature of the electric motor 1, a frequency sensor 3, rigidly connected to the shaft of the electric motor 1, an amplifier 4 of the sensor signal, a reference frequency generator, counters 6 and 7, a quantization and control unit 8, gates 9 and 10, code setter 11, registers 12 and '13, adders 14-17, control signal gate 18 and three code control units 19 ”20 and 21.

The output of the frequency sensor 3 of the speed is connected to the inputs of the amplifier 4. The outputs of the generator 5 of the reference frequency are connected respectively with the counting input of the second counter 7, the first input of the valve 9 and with the input of the quantization and control unit 8. The output of the first gate 9 is connected to the counting input of the first counter 6, the R input of which is connected to the quantization and control unit 8, and the outputs of the bits of the counter are connected to the first inputs of the first adder 14, the second inputs of which are connected to the outputs of the code setter 11. The outputs of the first adder 14 are connected to the inputs of the first register 1 2 and to the inputs of the code control unit 19, the first outputs of which are connected to the control signal valve 18, and the second output to the second input of the valve 9. The clock input of the first register 12 is connected to the corresponding output of block 8 quantization and control, and the outputs of the register 12 are connected to the first inputs of the second 15 and third 16 adders, the second inputs of which are connected to the outputs of the bits of the second register 13, the inputs of which are connected to the outputs of the third adder 16, to which also the inputs of the third block 21 of the code control, one of whose outputs are connected to the corresponding inputs of the valve 18 of the control signal, and the other output is to the second input of the valve 10, the first input of which is connected to one of the outputs of the quantization and control unit 8, and the output is connected to the clock the entrance of the second register. 13. The outputs of the second adder 15 are connected to the first inputs of the fourth

989721 of the 6th adder 17 and with the inputs of the second code control unit 20, the outputs of which are connected to the inputs of the gate 18, and its output - to the input of the key element 2. The second inputs of the fourth adder 5 "are connected to the outputs of the bits of the second binary counter 7. The output of the amplifier 4 is connected to the block 8 quantization and control.

The DC electric drive ra-u operates as follows.

The signal from the reference generator 5 is fed to the counting input of the first counter 6 through the valve 9. At the outputs of the bits of the counter 6 * 5 an increasing code appears, which is summed with the constant code from the output of the code setter 11. The total code goes to the inputs of the bits of the first register 12. 20

Simultaneously with the output of the amplifier 4. sensor signal to the input of the quantization and control device 8, pulses are received with a period determined by the rotation speed of the electric motor 25 of the motor 1. The quantization and control unit 8 quantizes these pulses with the pulses of the reference generator 5 and generates a signal allowing the census the total code in the first register 12, after which the block 8 gives a signal to reset the first counter 6. After this, the first counter 6 is refilled in such a way that by the arrival of the next pulse ₃₅ census in the first register 12 at the output of the counter 6, a code is generated proportional to the next frequency period of the rotation speed sensor 3. 40

In steady state operation is repeated.

From the outputs of the first register 12, the code goes to the inputs of the second 15 and third 1b adders. In the second register _{45, the} record 13 is made in the same way as the record in the first register 12. The code copied to the second register 13 ”is sent to the other inputs of the third adder 16. Thus, at the time of the next census, the code equal to the sum of codes is entered into the second register 13 the last period of the frequency of the speed sensor 3 and the code recorded in it earlier, From the output of the second register 13, the result is fed to the inputs ^{5 of the} second adder 15. At the output of the second adder 15, a code is generated containing information on the proportional and integral components of the speeds the rotation of the electric motor 1. From the output of the second adder 15, the resulting code is fed to the inputs of the fourth. of the adder 17 ”to the other inputs of which signals from the output of the second counter 7. The code on the output. The second counter 7 cyclically repeats that when summed with the code at the other inputs of the adder 17, the overflow signal periodically appears at the output of the adder 17, which disappears with each overflow of the second counter 7. The frequency of occurrence of the overflow signal is determined by the frequency of the reference generator 5 and the capacity of the second counter 7 _f and the duration of the overflow signal depends on the value of the code coming from the output of the adder

15. From the output of the fourth adder 17, the signal is supplied to the input of the valve 18. Thus, at the input and output of the valve 18 of the control signal, there is a pulse train with a constant frequency and variable duration, which is supplied to the key element 2 and then to the electric motor G.

Code control blocks are designed to reduce transient times and improve capture.

The first code control unit 19 determines the sign and value of the code at the output of the adder 14 and, when this code is exceeded, determines a signal to accelerate or decelerate to valve 18 depending on the code sign, and when the frequency of the sensor 3 exceeds the speed of a certain value, it closes valve 9.

The second block 20 of the code control determines the output of the code of the second adder beyond the permissible limits and outputs a si -, acceleration or deceleration tax to the valve of the control signal 18. The third block 21 of the code control determines the boundaries of the linear zone of operation of the blocks and 13 and when one of the boundaries is reached, it gives an acceleration or braking signal to the valve 18, and also closes the second valve 10.

The gate 18 of the control signal transmits pulses from the fourth adder 17 in the absence of acceleration and braking signals. In the presence of an acceleration or braking signal, the valve 18. sets the key element 2 in the corresponding state.

So when accelerating the electric motors 1 or when switching to a higher rotation speed at the first moment of time, the duration of the frequency periods of the speed sensor 3 significantly exceeds the nominal value, which is fixed primarily by the code control unit 19. It blocks the passage of pulses from the output of the fourth adder 17, a signal is supplied to the input of the key element 10 and 2, ensuring [connection of the electric motor 1 'to the maximum possible constant voltage for it, which ensures its accelerated acceleration, 15

The control unit 21 of the code provides a signal to the input of the valve 18 of the control signal, confirming the need for acceleration. The end of the acceleration signal is determined by the moment when the code control units 20 19, 20 and 21 give a signal indicating that the codes of the controlled adders are within acceptable limits and the electric drive has developed a rotation speed in the linear regulation zone.

A similar operation occurs when braking an electric drive or when switching to a lower speed of rotation.

Broke 19 code control by the value of the code at the output of the first adder 14 determines that the duration of the frequency period of the speed sensor 3 is less than ₃₅ required, and therefore, a signal is received from the output of the gate 18 of the control signal from it, blocking the passage of pulses from the output of the fourth adder 17 . The output of the Vienna ₄₀ till, 18 signal appears that sets a key element 2 in a position where the motor 1 is deenergized, and its winding is short-circuited, providing a Dean ₄₅ nomic braking actuator. The need for braking is confirmed by the block 21 code control. Braking is stopped as soon as the rotation speed becomes close to _{50 the} new required value and the control system enters the linear zone of operation, which is determined by the value of the codes.

During operation of the actuator ⁵⁵ at an uneven load moment, the magnitude of which 'varies with a significant frequency, may occur

98972I 8 times when the values of the codes of the first 14 and third 16 of the adders are admitted, but their total code has a value that indicates the approach to the boundary of the linear zone of the drive. In this case, the code control unit 20 at one of its outputs generates an acceleration or deceleration signal supplied to the input of the valve 18 of the control signal, which provides such a correction of the rotation speed at which the electric drive operates on the optimal section of the linear operation zone.

This electric drive does not contain devices with large time constants; the absence of such devices favorably affects the operation of the electric drive in the low-speed region and allows controlling the rotation speed in a wider frequency range, including frequencies much lower than the rated speed of the electric motor.

Introduction code control devices to minimize ⁴ duration transients during acceleration, deceleration and transition from one rotational speed to another, which in turn facilitates capturing a new mode of operation, the drive, eliminates the possible oscillations inherent in systems with regulation by the integrated component speed, provides aperiodic transients, which reduces the regulation time and makes the electric drive faster.

Claims (2)

1.Zimin E.N., Yakovlev V.I. Automatic control of electric drives. M., Higher School, 1979. 2. USSR author's certificate W, cl. H 02 P 5/06, 1978. 7 rl