SU761933A1 - Photoelectric apparatus for measuring angle of syncronous machine - Google Patents

Description

The invention relates to instrumentation, in particular to the device, m for measuring the angle of a synchronous machine in static and dynamic modes.

A device for the intention of the angle машины of a synchronous machine, based on measuring the phase shift between the voltage taken from the sensor of the angular position of the shaft, contains a sensor, the phase emf of which depends on the angular position of the shaft, recorders of a sinusoidal voltage through zero (threshold elements), differentiating circuit, multivibrator standby, controlled sawtooth generator, electronic key, memory capacitor, low pass filter, differential voltmeter and automatic adjustment unit amplification factor of a voltmeter, performed on diodes, capacitors and resistors [1].

In the known device, the use of a block for automatically adjusting the gain of a differential voltmeter makes it possible to slightly increase the measurement accuracy and eliminate the effect of a change in the frequency of the reference (mains) voltage. However, the disadvantage of the known device is the lack of high measurement accuracy in dynamic pe2

zhimnh works of the synchronous machine. This is explained by the fact that the accuracy of operation of this device largely depends on the linearity of the sawtooth generator.

5 voltage, stability of electronic circuit parameters and memory capacitor. Cro? Moreover, the presence of a low-pass filter significantly reduces the speed of this device and introduces a very significant θ error in the measurement result during dynamic modes of synchronous operation.

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The purpose of the invention is to improve the accuracy and speed and simplify the design.

This goal is achieved in that a device containing an angular shaft sensor and a registering unit is inserted in series with a network voltage frequency multiplier and a radiation source, a disk raster grating fixed on the shaft of a synchronous machine, a sector raster grating fixed on the machine body, sequentially United photoreceiver and detector, the output of which is connected to the recording unit, two optical systems, the first of which is located between the radiation source and rastro761933

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the second is between the sector raster grid and the photodetector.

“The latter circumstance allows us to significantly simplify the circuit diagram of the device, as well as to improve the measurement accuracy, since“ the most unstable elements, such as a sawtooth generator, a memory capacitor and a differential voltmeter, are excluded from the circuit.

The block diagram of the device is shown in FIG. one; in fig. 2 shows the stress plots explaining his work.

A photoelectric device for measuring the angle Θ of a synchronous machine contains a multiplier 1 of mains voltage and _c , consisting of two series-connected blocks 2, 3, a photoelectric transducer of the angular position of the shaft 4, containing a radiation source 5, a disk raster 6, a pie raster grating 7 , optical systems' 8, 9 and photodetector 10; the detector 11 and the recording unit 12, 13 is the shaft of the synchronous machine.

The radiation source 5 can be made on the basis of light-emitting diodes. The disk and sector gratings have an identical construction, i.e. they are made “with the same number of strokes, pupil sizes and steps.

The multiplication factor of frequency 1 of the mains voltage ί is chosen so that the frequency of the converted voltage and _c / is equal to the overlap frequency of the strokes of the raster gratings ω _ρ at a given nominal rotor speed of the synchronous machine l „. The overlap frequency of the photoelectric converter strokes is determined by the lattice pitch and is ω _ρ = —sec ~ ', where «„ is the nominal rotor speed of the synchronous machine, rpm; t is the number of strokes of the disk array.

The network (reference) voltage of 11 _s = = ί / _Β 8ίη <Μ after multiplication in multiplier 1 is converted by the radiation source 5 “into light pulses with frequency ον '. The resulting light pulses are sent by the optical system 8 to the measuring interface of the raster gratings 6, 7. Since the frequency of the light pulses emitted by the source 5 is equal to the overlap frequency of the lines of the photoelectric converter, when the angle Θ is zero, the light pulses do not arrive at the photodetector 10. When the angle измерение is measured, the disk "lattice 6 is shifted" relative to "sector lattice 7, and light impulses of the radiation source 5 arrive at the photodetector 10." 11, in which the signal is proportional to the angular displacement of the gratings, that is, the angle Θ.

Frequency multipliers increase the angle measurement accuracy измерения, and the electrical connection of the radiation source through the frequency multiplier with the mains voltage makes it possible to measure the angle по not by the phase shift between the mains voltage and the pulses taken from the angle sensor of the shaft position, but by the intensity of the light flux, passed through the raster lattice at their relative displacement.

Claims (1)

Claim A photoelectric device for measuring the angle Θ of a synchronous machine, containing a shaft angular position sensor and a recording unit, characterized in that, in order to improve accuracy and speed, the serially connected multiplier of the mains voltage and the radiation source, a disk raster grating mounted on the shaft of a synchronous machine, a pie raster grating mounted stationary on the machine body, connected in series with a photodetector and a detector, the output of which is connected to egistriruyuschemu unit, the two optical systems, the first of which is located between radiation source and scanning grating disk, 'the second - between the sector scanning grating and a photodetector.