SU1585765A1 - Method of digital measuring of engine rotational speed - Google Patents

Abstract

The invention relates to automation, relates to an adjustable electric drive and can be used to create digital speed controllers, mainly oriented to microprocessor circuitry, for various types of electric drives. The purpose of the invention is to improve the dynamic characteristics of the electric drive controller by accelerating the process of measuring the rotational speed. The goal is achieved by dividing the entire range of rotational speeds into a number of measurement subranges, for each of which the pulse tachogenerator signal is converted into a signal optimal for that subband, the parameters of all converted signals are measured simultaneously and simultaneously determined depending on the speed reference signal from measured signals. 2 Il.

Description

The invention relates to a controlled electric drive and automation, can be used to create digital rotational speed controllers, mainly focused on microprocessor circuitry, for various types of electric drives.

 one

. The purpose of the invention is to improve the dynamic characteristics of the controller

 electric drive by speeding up the rotational speed measurement process.

Figure 1 presents a diagram of the device, realizing the proposed method; figure 2 - the algorithm of the device.

: The device contains a pulse tachogenerator 1 mounted on the shaft of the control object, a crystal oscillator 2 generating a stable frequency pulse sequence, a block of counters 3, the number of counters in which is determined by the number of assigned measurement subbands, the device 4 setting the rotation speed and the control circuit 5, which forms the output rotational speed information in a digital code for controlling the control of the drive controller.

The device works as follows.

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Splitting the entire range of rotational speeds of the electric drive into a number of measuring subranges allows applying the control accuracy, speed and resolution of the pulse tachogenerator (number of pulses per shaft rotation) to a particular measurement parameter in accordance with the specified control accuracy, speed and resolution. This can be a tachogenerator pulse counting over a reference period of time (conveniently at high rotational speeds when the tachogenerator pulse frequency is high) or high stable frequency pulses counting over the tachogenerator pulse period (conveniently at low speeds of tachogenerator / mountain low ). In addition, different variations of these parameters can be applied on each measuring subrange (different durations of the reference time interval, frequency division of the tachogenerator pulses, etc.). Such a parametric variation makes it possible to obtain specified accuracy and measurement time in a wide range of rotational velocities. At the same time, the accuracy, measurement time, and width of the adjustment range are practically unlimited and are determined by the selected number of measurement subranges and the specific technical characteristics of the device implementing this measurement method. Measurement of all predetermined parameters (counting of the corresponding pulses) is performed simultaneously. At the same time, only one of all these parameters actually corresponds to the true rotational speed and ensures the specified accuracy. In order to immediately determine this unique parameter for a given speed, an analysis is made of the value of the rotational speed, the magnitude of which determines the working subband and the corresponding parameter, and this analysis is performed simultaneously with the pulse counting, which does not delay the measurement process than this method favorably with the prototype.

In the case of abrupt transients (speed leap), change

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rhenium is carried out as follows.

With an abrupt increase (decrease) in the rotation speed setting, a new measuring subrange is selected, which due to the inertia of the control object (electric motor) at the first moment will not correspond to the true rotation speed. At this moment, the measurement takes place with lower accuracy, and the result is close to the minimum (maximum), which provides the maximum effect on the speed controller and the rapid establishment of a new rotation speed,

The input information comes from the output of the pulse tachogenerator 1 to the input of the block of counters 3 in the form of a pulse sequence whose frequency is proportional to the speed of rotation. At the same time, a pulse sequence is applied to the same block. a stable frequency from the output of the crystal oscillator 2. As part of a block of counters 3, there are a number of main counters that perform measurement of parameters, depending on the speed of rotation. The number of these counters is determined by the number of measuring, subranges. In addition, in block 3, there are several auxiliary counters (timers) that perform the functions of frequency removal and the formation of reference time intervals. All major meters that measure are started at the same time and each counts its own parameter. Depending on the parameter, the inputs of these counters are connected either directly to the outputs of devices 1 and 2, or through auxiliary counters. At the end of the measurement, the counters stop, storing the received information in their registers, and give a readiness signal to the control device 5. The device 5 can be performed on one of the microprocessor sets (for example, series K580) with a standard architecture. All the connections of the microprocessor with the I / O devices shown in Fig. 1 are also standard.

Device 5 can be addressed to any of the main

counters, read the contents of their registers via a common data bus, and start all the counters to initiate a new measurement cycle. The rotation speed setting device 4 issues a digital code corresponding to the rotation speed to be set, which is periodically read by the control device.

A block diagram of the operation of the microprocessor device 5 is shown in FIG. His work is organized cyclically and consists of two programs: the main program and the interrupt processing program. The interruption of the main program can occur upon the readiness signal of each of the main counters. Such an organization of the program provides the maximum approximation to the principle of simultaneous operation of all measuring counters and analysis of the value of the reference signal, which is a necessary condition for the implementation of this method of measurement.

The effect of reducing the measurement time due to the application of the method is the greater, the greater the number of subbands.

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1585765

those. The application of this method is effective in designing a precision servo drive operating in a wide range of rotational speeds.

Claims (1)

Formula and inventions The method of digital measurement of the engine speed in an adjustable electric drive system, in which the whole range is divided into several sub-ranges, for each of which the pulse tachogenerator signal is converted into a signal optimal for this sub-band, and a measurement result is given for the subsequent calculation of the control action that differs that, in order to improve the dynamic characteristics of the control system by speeding up the process of measuring the rotational speed, the parameters of all Call signals simultaneously and also simultaneously determined depending upon the signal specifying the optimum frequency from the measured signals. CiJe / 77VU / M1 with emtiUKNi Counting1 L Bbfxod 1 Essential program initialization portob & 6odafSbiBoda Informatics Run ci emt uffoe Analysis of the signal value of the task, 8y5 or ctjemvu / a Resolution npepi, / Sa- minroprocessor Mathematics processing Result / PA previous .1 wh / 6d I resumta / zol / e a La Waiting for interruption Program about skirts lreryvoni CwmbfSaHtje pe3yjfbmama accounts Running ct / emviwoS 3anpem interrupt Return