SU1495758A1 - System for stabilization of electric motor rpms - Google Patents

Abstract

The invention relates to the field of automatic regulation and can be used in high-precision systems for stabilizing the speed of engines when operating at low speeds. The purpose of the invention is to improve the accuracy of stabilization of instantaneous speeds in the range of infra-low speeds. This is achieved by using in the system, along with the main control loop, based on a pulse velocity measurement, a correction loop, built on the basis of continuous velocity measurement and phase correction of the pulse signal from the measurement results. 3 il.

Description

The invention relates to the field of automatic control and can be used in high-precision systems for stabilizing the speed of engines when operating at infra-speeds.

The purpose of the invention is the higher accuracy of stabilization of instantaneous speeds in the range of fast speeds,

Figure 1 shows the structural diagram of the system; on Go2 - a flow diagram for calculating the speed deviation; FIG. 3 is a simplified system schematic diagram.

The system contains a second phase detector, integrator 2, an asynchronous counter 3, a controlled oscillator 4, a reference frequency generator 5, a first phase detector 6, a pulse sensor 7 of the motor shaft speed.

KJyuchevyy power amplifier 8, electric motor 9, continuous sensor 10 of the speed of the motor shaft, computer. 11 speed deviations, comparator 12, key element 13, integrator 14, comparator 15, task code information bus 16. The calculator 11 contains an operational amplifier 17, DAC 18, integrator 19.

The system works in the following way.

The first input of the phase detector 1 is supplied with a voltage with a frequency fi proportional to the angular velocity of rotation of the shaft of the electric motor, measured by the pulse velocity sensor 7. The second input of the phase detector 1 receives a pulse signal of frequency f5 from the asynchronous counter 3, and NS / N, where N

YKGLI

U1

 ate

00

N

3 aus

the current and maximum value of the target code, and g the frequency of the pulse signal at the output of the controlled oscillator 4 "The output signal of the phase detector 1 through the integrator 2 changes the frequency of the signal of the controlled oscillator f: until the condition f is fulfilled. N, / N,

f, f3

4 g, 3ma1h

Thus, blocks 1-4 together are intended to increase the frequency of the signal f by a factor of ..

The sawtooth signal with the frequency f from the output of the sawtooth voltage of the generator 4 through the comparator 12, where it is converted into a pulsed form, is fed to the phase detector 6, which is compared with the pulse signal of the constant reference frequency fg- The motor rotates until the condition is satisfied, 0 From which it follows that the rotation speed of the motor shaft is proportional to the magnitude.

 Max. The discrete method of measuring speed in the proposed system is the possibility of disturbed oscillations (deviations) of speed with frequency equal to and multiple c. The system is not sensitive to this. This phenomenon is most pronounced at infra-low speeds of rotation of the engine shaft.

A corrective circuit formed by a continuous speed sensor 10, a speed calculator 11 speed calculator and a comparator 12 is used to parry the speed deviations. The transfer function of the speed calculator 11 is determined by the relation (Fig. 2)

W (P)

LIi shlL Jlll + (TaN, / N,) P 9 Zma

de,

Qfl

I max

- max1-1mm value raboN

whose speed; M - the number of labels on the disk and 50 pulse speed sensor;

NI - task code; -j i,

5 max

the maximum value of the task code.

At the same time, at the maximum working speed, the time of the block 11 is the smallest, and at the minimum - the largest. Rebuilding the parameters of this

block B of the chilling code function N ensures that the amplitude of the output signal of the block is independent of the value of the given speed with the same amplitude of the periodic signal of the speed deviations SOdb 9 measured by the sensor 10. The output signal of the block 11 changes the phase of the pulses at the output of the block 12 entering the input of the comparator 12 with respect to its thresholds in such a way that the advance in phase corresponds to an increase in speed.

The transfer function of the correction circuit for the disturbance (Fig. 3), taking into account the integrating properties of the phase detector 6, has the form

Tr + 1

Tp + UK P

P-,

Whence it follows that with an increase in the gain of the Kdz system, the influence of the perturbation 01. "on the stabilizer

The controlled speed can be reduced. The correction loop is not sensitive to the constant component of the velocity due to the differentiating nature of the transfer function of the block 11.

Claims (1)

Invention Formula An electric motor speed stabilization system containing a series-connected reference frequency generator, a first phase detector, a key power amplifier, an electric motor, a pulse motor speed sensor, a second phase detector, an integrator, a control generator and an asynchronous counter connected by a code input to the information bus code of the task, and the output with the second input of the second phase vector, characterized in that, in order to increase the accuracy, it additionally contains Inline continuous shaft speed sensor. An electric motor, a speed deviation calculator and a comparator connected by an output to the second input of the first phase detector, while the output of the sawtooth generator voltage is connected to the second comparator input, and the code input of the deviation calculator is connected to the information code of the task code. R I Ana / ayu lal Z Output YU FIG. g W / 3 eJ