JPH0124454B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an analog optical conversion device, and more specifically, it converts the secondary electrical output of a voltage-current transformer into an optical signal using a light emitting diode, transmits it in analog form using an optical fiber, etc., and converts it into an optical signal. -Related to an analog optical conversion device that converts the signal back into an electrical signal using a diode or the like and outputs the signal.

Optical transformation devices that transmit signals using light can be made smaller and lighter because they are easier to insulate than electrical transmission type transformation devices, and the use of optical fibers to transmit signals of measured quantities solves the problem of guidance. It has great merits such as: Light-emitting diodes are often used to convert electrical signals into optical signals in such optical conversion devices because they have a wide range of linearity. It has the disadvantage that it cannot be converted, which causes a problem of large waveform distortion during analog transmission.

The purpose of this invention is to solve the above-mentioned problem. To put it simply, this invention uses optical transmission of AC zero-crossing phase detection pulses of a saturation transformer provided separately from a normal signal transmission section using light emitting diodes. By generating a correction signal synchronized with this on the optical receiving side and adding it to the signal of the normal signal transmission section, we have created an analog optical conversion device that accurately corrects waveform distortion caused by the light emission threshold of the light emitting diode. This is what we provide.

Hereinafter, this invention will be explained in detail based on embodiments shown in the drawings. Note that this invention is not limited to this.

Reference numeral 30 shown in FIG. 1 is an embodiment of the analog optical conversion device of the present invention, which is composed of a main signal transmission section 27, a correction signal transmission section 28, and a correction calculation section 29.

The main signal transmission section 27 includes a main transformer 1 , an electric-to-optical converter 3 , optical fibers 5 and 6 , an optical-to-electrical converter 7 and a differential amplifier 11 .

The correction signal transmission unit 28 includes the saturation transformer 2, the electrical
It consists of an optical converter 4, optical fibers 8, 9, an optical-to-electrical converter 10, amplifiers 12, 13 and bistable multivibrators 14, 15.

The correction calculation unit 29 includes AGC amplifiers 16, 17,
Differential amplifiers 18, 19, diodes 20, 21,
It consists of an inverting amplifier 22 and a summing amplifier 23.

Assuming that the primary current i is a sine wave alternating current, the output waveform of the main transformer 1 is the sine waveform shown in Fig. 2-2-a, and the output waveform of the saturation transformer 2 is the sine-waveform shown in Fig. 2-2-b. The result is a triangular pulse-like waveform. By appropriately selecting the transformer impedance and the load impedance, the output signal of the saturation transformer 2 will have a phase that has a peak at the zero crossing point of the output signal of the main transformer 1.

The output of the main transformer 1 is converted into optical output by separate positive and negative light emitting diodes in the electrical-to-optical converter 3.
Positive and negative signals are separately transmitted to the optical receiving side through two optical fibers 5 and 6. These optical signals are converted into electrical outputs by separate positive and negative PIN photodiodes in the opto-electrical converter 7, and are combined and amplified by the differential amplifier 11, resulting in the pulsating flow shown in FIG. 3-a.
θ in the figure is the light emission delay angle caused by the light emission threshold voltage of the light emitting diode. If the threshold voltage is Eth and the maximum AC value applied to the light emitting diode is Emax, then θ=Sin ^-1 Eth/Emax. and is almost inversely proportional to the maximum AC value Emax.
This means that it is approximately inversely proportional to the maximum value of the primary current i.

The output of the saturation transformer 2 is also converted into optical output by separate positive and negative light emitting diodes in the electric-to-optical converter 4, and transmitted separately to the optical-to-electrical converter 10 on the receiving side through two optical fibers 8 and 9. be done. The electrical output of the optical-to-electrical converter 10 is amplified by amplifiers 12 and 13, respectively, and bistable multivibrators 14 and
15 to generate the rectangular waves shown in FIG. 3-b and 3-c.

On the other hand, the outputs of the amplifiers 12 and 13 are shaped by the AGC amplifiers 16 and 17 into triangular waves as shown in FIGS. 3-d and 3-e with a peak value _ER ' equal to the rectangular wave voltage _ER . The pulse width θ′ of the triangular wave is the above-mentioned θ
Similarly, it is almost inversely proportional to the maximum value of the primary current i, so by appropriately selecting the core material and cross-sectional dimensions of the saturation transformer 2, it is always made to be twice the above-mentioned θ.

These triangular waves are applied to the inverting terminals of the differential amplifiers 18 and 19, respectively, and are subtracted from the output voltages of the bistable multivibrators 14 and 15, which are applied to the non-inverting terminals, respectively, so that the output voltage of the amplifier 11 corresponds to the luminescence value. It is amplified and output so that the amplitude Ec matches the voltage. Therefore, the output of the differential amplifier 18 is set to 3-f in FIG. 3, and the output of the differential amplifier 19 is set to the third
The waveform shown in Figure 3-g is obtained.

The outputs of these differential amplifiers 18 and 19 are outputted by diodes 20 and 21, respectively, to cut negative side spike voltages, and the output voltage of the diode 21 is transferred to an inverting amplifier 22.
After the polarity is inverted at , the output voltage of the diode 20 is added to the output of the differential amplifier 11 by the summing amplifier 23 . What should be noted is that these calculations should be performed at a voltage level that is sufficiently higher than the shoulder voltage of the diodes 20 and 21.

A sine wave alternating current as shown in Figure 3-3-h is obtained at the output of the differential amplifier 23, but this is a correction voltage (shaded area) created on the optical receiving side, and the main signal transmission section 2
This is a signal obtained by correcting the threshold distortion of the light emitting diode included in the output of No. 7.

As a modified example, the main transformer 1 and the saturation transformer 2 may be used as voltage transformers.

As can be understood from the above explanation, the analog optical conversion device of the present invention can accurately restore the primary AC signal, so there are no restrictions on the frequency characteristics and phase characteristics, and the analog optical conversion device of the present invention is Be able to meet the standards.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the analog optical transformer of the present invention, FIG. 2 is a waveform diagram showing the output waveforms of the main transformer 1 and the saturation transformer 2, and FIG. 3 is the same as that shown in FIG. FIG. 3 is a signal waveform diagram of each main part of the device shown in FIG. 1... Main transformer, 2... Saturation transformer, 3, 4...
...Electric-optical converter, 5,6,8,9...Optical fiber, 7,10...Optical-electrical converter, 11,18,
19...differential amplifier, 14,15...bistable multivibrator, 16,17...AGC amplifier,
23... Addition amplifier, 30... Analog optical conversion device.

Claims (1)

[Scope of Claims] 1 (a) A transformer that outputs an electrical signal to the secondary side in response to an AC electrical signal on the primary side, and an electricity that converts the output electrical signal of the transformer into an optical signal using a light emitting diode and outputs it. - Optical converter and its electricity - A main signal transmission section consisting of an optical-to-electrical converter that converts the optical signal of the optical converter into an electrical signal by a light receiving element and outputs it, (b) Zero crossing point of the primary side AC electrical signal A saturation transformer that outputs a triangular pulse-shaped electrical signal to the secondary side in response to a signal in the vicinity, an electric-to-optical converter that converts the output electrical signal of the saturation transformer into an optical signal using a light emitting element and outputs it. A correction signal consisting of an optical-to-electrical converter that converts the optical signal of the electric-to-optical converter into an electric signal using a light receiving element and outputs it, and a bistable multivibrator circuit that inverts using the output signal of the optical-to-electrical converter as a trigger. a transmission section; and (c) a trapezoidal AC-shaped electric signal is synthesized with the output of the optical-to-electrical converter of the correction signal transmission section and the output of the bistable multivibrator circuit, and this and the optical signal of the main signal transmission section are combined. An analog optical conversion device comprising: a correction calculation unit comprising a calculation circuit that synthesizes an electric signal faithful to the primary side AC electric signal with the output of an electric converter.