SU949504A1 - Contactless tacho generator - Google Patents

Description

The invention relates to measurement technology, and more specifically, to devices designed to measure angular velocity of rotation, and can be used, for example, in speed stabilization systems for most non-contacting constant-torque motors (DPDC) with pulse-width rotor position sensors, as well as in automatic control systems for generating tacho pulse signals.

Non-contact reversible DC generators are known that 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, the reversing unit is made on reed switches, switch :) whose coils are connected to the output of the air sensitive unit 1.

The disadvantages of these tachogenerators are the coordinate delay of the moment of switching the reversing unit in accordance with the time of reverse of the rotation of the generator shaft /

as well as the complexity of the presence of an electromechanical unit.

It is also known a device for measuring the rotational speed of a contactless permanent-torque motor, contains a two-phase pulse-width sensor position, the first output of which is connected to the first input through the first driver

10 of the OR circuit, the second input of which through the second driver is connected to the second output of the position sensor, and the output to the first input of the coincidence circuit, the second input of which is connected

15 through serially connected one-orbit, the third driver and the inverter with the first output of the position sensor, and the output with the first trigger inputs, the second input of which

20 is subconnected to the output of the third driver, and the output to the first input of the comparator and to the input of the delay circuit, the output of which is connected to the second input of the comparator (2.

25

The disadvantage (m "(the device is its complexity (the presence of six sensitive elements, i.e., their doubled set) and the large number of electrical wires connected to it)

30 between the sensor and the electronic unit 1 block.

The purpose of the invention is to simplify the design by reducing the number of sensing elements and reducing the number of electrical connections between the electromechanical part and the Hbff-i electro unit.

The goal is achieved by contacting a tachogenerator with three integrators, two adders and two drivers, the first output position sensor through the first integrator connected in series, the first cvMMaTop and the fourth driver connected to the third input of the OR circuit, the fourth input of which is connected The fifth fifth driver, the second adder and the second integrator are connected to the second input of the position sensor, while the second input of the first adder is connected to the first input of the second totalizer ra, the second input of which via a third integrator connected to the output of the inverter.

1 shows a functional diagram of the device; Figure 2 shows signal plots explaining how the device works.

The contactless tachogenerator contains a two-phase pulse-width position sensor 1, two outputs of which through series-connected drivers 2 and 3, OR circuit 4, coincidence circuit 5, trigger 6, delay circuit 7 are connected to the first input of the comparator 8, to the second input of which trigger output 6 is connected. The device contains an inverter 9 connected in series to the first input of the position sensor, a third driver 10, whose input is connected to the second input of trigger b, and a one-shot 11, the output of which is connected to the second input m scheme 5 matches. The tachogenerator contains three integrators 12-14, two adders 15 and 16, and two formers 17 and 18. Position sensor 1 outputs through series-connected circuits consisting of the first 13 and second 14 integrators, first 15 15 and the second 16 adders, and the fourth 17 and The fifth 18 drivers are connected to the inputs of the assembly 4. A second output of the integrator 14 is connected to the second input of the first adder 15, and an output of the inverter is connected to the second input of the second adder 16 via the third integrator 12.

The device works as follows.

When the sensor shaft 1 of the position rotates, pulse-width signals 19 and 20 arrive from its outputs, the laws of which change from the angle about (19 and 20, Fig. 2) are out of phase by 90. When implementing tachometer

devices according to these laws produce significant output ripple. In the device, the phase splitting is achieved in an electronic unit, through the introduction of additional equipment - 12 - 1B units.

The signal from the first output of sensor 1 is inverted by inverter 9, and through driver 10 triggers a one-shot 11, the output pulse 21 of which is resolving for coincidence circuit 5. Pulse 21 is located in the middle of the pulse width modulation period ..

Duration of the signal 21 Corresponds to the length of the sections of sinusoids 19, 20, 22 and 23 that are close to linear. Moreover, the sinusoids 19 and 20 of the sensor 1 are fed to the formers 2 and 3, the output short pulses of which correspond to the position in the period T of the information front of the PWM Signals 19 and 20 are integrated by the first and second integrators 13 and 14, and the signal 19 is inverted by block 9 and then also integrated by the third integrator 12. Thus, by the end of each period, voltages corresponding to the durations of signals 19, 20 and 19 are obtained at the outputs of the three integrators.

In the adder 15, the signals 19 and 20 are added, and the driver 17 produces a short pulse, the location of which in period T corresponds to law 22. Similarly, signals 19 and 20 are added in adder 16, and driver 18 produces a signal 23.

Four sequences of short pulses from the outputs of shapers 2, 3, 17, and 18 arrive at the assembly circuit, the relative position of which (pulses) in the period T of the PWM corresponds to laws 19, 20. 22 and 23.

The pulses from the output of the circuit OR 4 arrive at the circuit 5 of coincidence, which passes one output trigger 6. The signal from the output of the assembly only during the existence of the pulse 21 of the output of the one-oscillator. So, the trigger on the signals of two PWM fronts: fixed - from the output of the imaging device .10 and informational - from the output of the matching circuit 5 forms the PWM signal 24, the law of changing the duration of which is shown by a solid line (Fig. 2).

The output pulses of the trigger 6 are fed to one input of the comparator 8 through the delay circuit 7, and to the second directly. A signal appears at the output of the comparator 8, the duration of which is proportional to the speed of rotation of the shaft of the position sensor 1.

Thus, in the proposed device, instead of installing an additional set of sensitive elements in position sensor 1, a two-phase pulse signal was converted (with a shift of 90) into a four-phase (with a shift of 45) relative to each other. In this case, the pulsations of the tachometric signal are insignificant, since narrow pongs of sinusoids close to linear (line 24) are used to determine the speed, and the number of electrical connections of the position sensor, the electronic unit, is halved.

Claims (2)

1. Author's certificate of the USSR 386337, cl. G 01, 1973. 2. Authors certificate of the USSR 662867, cl. G 01 P 3/46, 1979 (prototype).