SU1032424A1 - Motor rotation speed adjusting system - Google Patents

Description

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9iv. 1 The invention relates to C11 automatic control systems, in particular to engine speed control systems. Known systems for controlling the speed of rotation of an engine, comprising a series-connected master oscillator, a correction unit, are made; for example, in the form of a frequency detector, an adder, the second input of which is connected to the output of the frequency detector, an amplifier “motor, a tachogenerator, made in the form of a pulse sensor, the output of which is connected to the inputs of the frequency delntel and the frequency detector. Using a pulse generator of a tachogenerator, the frequency of the pulses is directly proportional to the speed of its rotation. shaft, allows to achieve high accuracy measurement of the rotational speed of the engine. High measurement accuracy in a large range of speeds creates the necessary conditions for obtaining a large range of precise control of the rotation speed of the engine. However, these systems have a small range of static, i.e. accurate speed control, and (the high precision characteristics of the tachogenerator cannot be fully utilized. Of the known devices, the closest to the proposed technical essence is an engine speed control system containing first and second digital-to-analogue converters that drive a generator whose output is connected to the input the first frequency divider and the input of the correction unit, the output of which is connected to the first input of the adder, the second input of which is connected to the output frequency about the detector, and the output via serially connected amplifier-converter, motor and tachogenerator - with the inputs of the frequency detector and the second frequency divider. The average rotational speed of the engine in a known system with a high degree of accuracy corresponds to a given speed 2. A disadvantage of the known system is non-smooth rotation engine at low speed of rotation. Non-rotation is caused by errors in the digital-to-analog converters, which in the course of their work periodically pass through all their conditions and in the presence of conversion errors, form cyclic errors with a period equal to the perirdure between two adjacent faults of one of the dividers. At low engine speeds, these perturbing effects are in the passband of the control system and cause a non-smooth rotation of the engine. The purpose of the invention is to improve the accuracy of the engine speed control system. The goal is achieved by introducing a digital adder into the system, the first input of which is connected to the output of the third frequency divider, the second input to the output of the second frequency divider, the first and second outputs, respectively, through the first and second digital-to-analogue converters respectively. Such a design of the system allows full use of the high accuracy of the tachogenerator. FIG. 1 is a block diagram of the system; Fig. 2 shows timing diagrams explaining the operation of the proposed system. The system for automatically controlling the rotational speed of the motor contains a master oscillator 1, a digital adder 2, an adder 3, an amplifier converter k, an engine 5, a tacho generator 6, a first frequency divider 7, a frequency detector 8, a correction unit E. a second frequency divider 10, the first 11 and second 12 digital-to-analog converters. FIG. 2 denotes: a, b - signals at the outputs of the generators; c, d numbers coming from the outputs of dividers 10 and 7; d, e - the numbers at the outputs of the digital adder 2; g, h - signals at the outputs of digital-to-analog converters 11 and 12, and - smoothing signal at the output of the converter-converter:, k - signal of the speed of rotation of the engine 5, t - time. The system works as follows. With the arrival of each pulse of signals a, b, dividers 10 and 7 increase the values of the numbers registered in them by one. From the outputs of drivers 10 and 7, the numbers in the forward binary code, and the numbers t in the reverse or additional binary code arrive at the inputs of the digital adder 2. The representation of the number I in the reverse or additional binary code provides the number d in the digital adder representing the difference the numbers are b and 2, namely,% в - г, with B7f t; And +4 2, at С2,,. where and - the volume of the digital adder 2 and dividers 7 and 10 frequencies. The number e is a number, represented in reverse binary code, derived from the number & by replacing each number of this number with zero n units and ones with zero. The numbers 9 and in the converters 11 and 12 are converted into voltages X and. The difference of these voltages, formed by adder 3, amplified and smoothed by amplifier t, is converted

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JlrlЛJUlшшллJгrlnnJШJmrlГЛЛЛJ to the signal tc, which controls the engine 5 - Because the variable component in the signal R has a high frequency equal to the frequency of signals a and 5, which is higher than the transmission of the engine 5, the signal r of the engine rotation speed does not contain a variable component, . motor 5 rotates smoothly. To change the rotational speed of the engine, they change the signal size fi by changing the frequency of the generator 1 In the proposed system, the errors from the converters 12 and 13 do not form low-frequency disturbing influences, since in the period between adjacent faults of one of the dividers, the transmitters 12 and 13 pass only two neighboring states, not all, as in the prototype. Therefore, in the proposed system, the motor rotates smoothly over a wide range of speeds, the engine speed is maintained with high accuracy, approaching the accuracy of the tachogenerator.

Claims (1)

SYSTEM OF REGULATION OF SPEED ‘ENGINE ROTATION GROWTH, containing the first and second digital-analog | converters, a master oscillator whose output is connected to the input of the first frequency divider and to the input Fie. The first is connected to the first input of the adder, the second input of which is connected to the output of the frequency detector, and the output through series-connected amplifier-converter, motor and tachogenerator - with the inputs of the frequency detector and the second frequency divider, characterized in that, in order to increase accuracy, a digital adder was introduced into the system, the first input of which is connected to the output of the first frequency divider, the second input - with the output of the second frequency divider, the first and second outputs, respectively, through the first and second Diff Browsers • with third and fourth inputs GO boo F *