SU662867A1 - Device for measuring contact-free dc motor rotational speed - Google Patents

Description

  i.

The invention relates to measurement technology, is intended to measure the angular velocity of rotation, and can be used, for example, in systems for stabilizing the rotational speed of non-contacting direct current motors (TIRs) with pulse-width sensors of the Rotor Position (DPR), as well as in automatic control systems development of non-reversible tachometric cl-s.

Non-contact reversible tachogens are known. The DC generators contain a synchronous alternator, the rotor of which is rigidly connected to the rotor position sensor, rectifier, phase-sensitive unit, reversing unit connected electrically to the rotor position sensor, and the reversing unit is made on reed switches switching windings of which are connected to the output of the phase-sensitive unit lU-,

In addition, contactless reversible tachogenerators are known. direct current, containing a multiphase synchronous generator, the statort winding of which is connected via a rectifier to a reversible

a bridge cascade controlled by voltage transducers with a position sensor containing four magnetic conductors with permanent magnetic and output windings connected with a logic device 2.

A common disadvantage of tachogenerators is the coordinate for the lag of the moment of switching the reversing unit relative to the time of the reverse of the rotation of the generator shaft.

Closest to the invention to the technical essence is a device for measuring the rotational speed of a contactless DC motor with a latitude. pulsed rotor position sensors,

made in the form of Tpiex two-input circuits AND, the inputs of each of which are connected in pairs with sensitive elements of a three-phase rotor position sensor, and the output is connected to the input of the OR circuit, the output of which is connected to the first input of the circuit

module two directly, and with the second input through a pulse delay circuit for carrier frequency (G).

The main disadvantage of the known device is the pulsation of the output voltage of the device due to the non-linearity of the selectable sinusoid sections used to generate the speed signal. The aim of the invention is to reduce the ripple of the output voltage of a device for measuring the rotational speed of a TAPD. This is achieved by introducing seven pulse shapers, an inverter, a matching circuit, an assembly circuit, a trigger and a generator into the proposed device, and three additional sensing elements connected with a phase shift relative to the first three sensing elements by 30 ° to the rotor position sensor, the outputs of the six DPR sensitive elements through six drivers are connected to the inputs of the assembly circuit, the output of which is connected to the first input of the coincidence circuit, to the second inputs of which through serially connected the seventh shaper generator and inverter, which is connected to the first input of the matching circuit, connects the first sensing element, and the output of the circuit, we match is connected to the first setup input of the trigger, to the second installation 18 of which the output of the trigger is connected to the input of the circuit delays of pulses for the period of the carrier frequency and with the second input of the circuit “addition by two. -. „...; .. In FIG. 1 shows a functional diagram of the device; in fig. 2 - dependence of the relative durations (duty ratio) of the output pulses of the DPR on the angle of rotation of the rotor; in fig. 3- timing diagrams explaining the principle of operation of the device circuit. The device for measuring the speed of rotation of the TIRBT consists of pulse-pulse DPR, which includes six sensitive elements, the outputs of which are connected to the assembly circuit 13 through six drivers, the output of which is connected to the first input of the coincidence circuit 14, the output of which is connected to the first installation input trigger 15. The output of one of the sensing elements, for example, the first I through the inverter 16 and the seventh driver 17, connected successively, is connected to: the input of the IS generator and the second setting 61 | input three Hera 15. The output of the generator 18 is connected to the second input of the matching circuit, and you (; one trigger 15 is connected to the first input of the "modulo two 19 addition circuit directly, and to the second input - through the pulse delay circuit for the period of the carrier frequency 20. The device works as follows: When the DPR shaft rotates, its pulse-sensitive elements 1 remove pulse-width-sequence, the duty cycle of which tf (see Fig. 2) varies according to the laws depending on the angle of rotation of the rotor, and the curves T |, T1.1Ga are shifted between themselves phase angle of ± 120 °, curves T4, fs-t 6 are also shifted between themselves in phase by angles of ± 120 °, and the systems iTf, ta, Ts and 14, T 5 T в form two three-phase sequences that are phase-shifted one relative to another 30 e. hail. In order to generate a pulse signal for the speed of rotation of the shaft BDPT, linear sections of sinusoids are selected. The selection scheme, which includes seven drivers, 17, inverter 16, generator 18, assembly circuit 13, matching circuit 14 and trigger 15, selects 30 ° sections from the system ZTj te - Pulses ft g (available at the inputs of the formers 7-н12 whose output pulses correspond to the leading edges of the ti-iyte sequences go through the assembly circuit 3 to the first input of the coincidence circuit 14. The pulses from the output of one of the sensitive DPR elements, for example, the first I, are inverted by the circuit 16 and arrive at the INPUT of the seventh former 17. impulses to The first, corresponding to the leading edges of the pulses 1 I, start the generator 18, which produces gating pulses Ui, which arrive at the second input of the coincidence circuit 14. At the output of the coincidence circuit 14 are those of the back edges of the sequences T (, the relative durations of which the condition of Go f is satisfied, i.e., the average duration of the pulses Г of the system 11 is 4-tg. The output pulses of the coincidence circuit 14 arrive at the first setup input of the trigger 15, the second setup input of which receives the pulses ode seventh shaper 17, corresponding to rising edges sequences tt -Te. At the output of the trigger, the ua modulated sequence Ua is restored (see Fig. 3), the relative duration of which varies with the linear law of the angle U of rotation of the DPR rotor. This dependence is shown in FIG. 2 line 21. The pulses from the output of the trigger 15 are fed to the input of the pulse delay circuit for the period of the carrier frequency 20 and to the first input of the “modulo-two” addition circuit 19, to the second input of which are pulses Uj from the output of the pulse delay circuit to the carrier frequency period. The duration of the output pulses. the device is equal to the difference between the durations of the signals Ua and the ultrasound of the neighboring pulses of the latitude-modulated sequence Ua and is proportional to the measured rotational speed of the shaft of the TIRD.

Claims (3)

1. USSR author's certificate number 386337, cl. G 01 P 3/46, 1973. 2. USSR author's certificate number 364900, cl. G 01 P 3/46, 1973. 3. USSR author's certificate number 503339, cl. G 01 P 3/46, 1976. fe h j YG.2