JPH05126867A - Controlling circuit of led of light-applied current-voltage sensor - Google Patents

Abstract

(57) [Abstract] [Purpose] Highly accurate temperature correction with a simple circuit configuration.
Provided is an optical applied current voltage sensor LED control circuit in an optical current voltage measuring device. An LED light emitting section 8, an optical sensor 11 for converting a current value or a voltage value of an electric line 12 into an optical modulation signal by using the Faraday effect or the Pockels effect, and a light receiving section for converting the optical modulation signal into an electric signal. 1, an amplification unit 2 that amplifies only the modulation component of the received light signal, that is, an AC component, a filter unit 3 that detects only the DC component from the received light signal, a reference voltage unit 7 that outputs a reference signal, and an output of the filter unit 3. And an output reference signal of the reference voltage unit 7 and outputs a control signal to the LED light emitting unit 8, a temperature detecting unit 9 for detecting the ambient temperature of the LED light emitting unit 8, and an input signal based on each input signal. And the arithmetic processing unit 4 that performs arithmetic processing, and the modulation error can be corrected by adjusting the reference signal value of the reference voltage unit 7 according to the ambient temperature change of the LED light emitting unit 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical current-voltage measuring device for measuring a voltage value or a current value of an electric line using the principle of the Faraday effect or Pockels effect by an electric field, and the temperature depending on the ambient temperature of an LED light emitting part. Make compensation,
The present invention relates to a current application voltage sensor LED control circuit.

[0002]

2. Description of the Related Art Conventionally, in order to perform temperature compensation in an optical applied current voltage sensor, (1) a coefficient corresponding to the ambient temperature of the LED light emitting portion is previously obtained, and the ambient temperature of the LED light emitting portion is constantly measured and observed. The configuration in which temperature compensation is performed by multiplying the data output from the amplification unit by a coefficient obtained in advance by the arithmetic processing unit, (2) Change in the ambient temperature of the device by always keeping the ambient temperature of the LED light emitting unit constant However, there is a configuration in which the light emission amount is always kept constant regardless of the above.

A conventional example will be described below with reference to the drawings. FIG. 5 shows the first conventional example. In FIG. 5, 1 is a light receiving section for converting a light modulation signal into an electric signal, 2 is an amplifying section for amplifying only a modulation component of the received light signal, that is, AC component, 3 is a filter section for detecting only a DC component from the received light signal, 4 Is an arithmetic processing unit that performs arithmetic processing based on each input signal, and 5 is an LE
D: a memory unit for storing a coefficient for the ambient temperature of the light emitting unit 8; a comparing unit 6 for comparing the output of the filter unit 3 with the output reference signal of the reference voltage unit 7 and outputting a control signal to the LED light emitting unit 8; Reference numeral 9 is a temperature detection portion for detecting the ambient temperature of the LED light emitting portion 8. Reference numeral 10 is an optical fiber for connecting the optical sensor 11 and the light receiving portion 1 using the Faraday effect by the electric field or the Pockels effect by the electric field and the optical sensor 11 and the LED light emitting portion 8. , 12 are electric lines.

In the conventional example configured as described above,
The temperature detection unit 9 constantly detects the ambient temperature of the LED light emitting unit 8, and the arithmetic processing unit 4 reads from the memory unit 5 a coefficient corresponding to the ambient temperature of the LED light emitting unit 8 detected by the temperature detection unit 9. On the other hand, the amplification unit 2 amplifies only the AC component of the electric signal detected by the light receiving unit 1 and outputs it to the arithmetic processing unit 4 as a measurement signal of the current value or the voltage value of the electric line 12. The arithmetic processing unit 4 multiplies the measured signal by the coefficient to correct the modulation output error due to the change in the ambient temperature of the LED light emitting unit 8.

Further, the DC component of the light receiving signal output from the filter unit 3 is such that a constant light receiving modulation signal can be obtained with respect to the light emitting characteristics of the LED light emitting unit 8 and various light amount change factors. The control signal to is corrected.

[0006]

However, in the above-mentioned conventional configuration, (1) it is necessary to set and store a coefficient in advance for the ambient temperature of the LED light emitting portion, and an extra memory for that is required. And Further, the resolution of the coefficient corresponding to the ambient temperature of the LED light emitting unit may cause an error corresponding to the minimum resolution in the temperature correction. In addition, the number of calculations for multiplying the measurement signal by a coefficient corresponding to the ambient temperature of the LED light emitting section has increased, which has been a cause of complicating and increasing the size of the calculation processing program.

(2) In the configuration for adjusting the ambient temperature of the LED light emitting section to be constant, it is necessary to provide a temperature control section, which makes the device large and the circuit complicated. Had problems such as.

The present invention is intended to solve such a conventional problem, and does not require a memory unit and a complicated and large-sized program, or a temperature control unit and a complicated circuit. An object of the present invention is to provide an optical applied current / voltage sensor LED control circuit in an optical type current / voltage measuring device that accurately performs temperature correction.

[0009]

In order to achieve the above object, the optical applied current voltage sensor LED control circuit of the present invention is an LED light emitting section for converting an electric signal into a light quantity in an optical system current voltage measuring apparatus, and an LED light emitting section thereof. A temperature detection unit that detects the ambient temperature of the LED light emitting unit, and light that uses the Faraday effect by the electric field or the Pockels effect by the electric field that converts the current value or voltage value of the electric line into an optical modulation signal that is proportional to the current value or voltage value. A sensor, a light receiving unit for converting a light modulation signal into an electric signal, an amplification unit for amplifying only a modulation component of the light reception signal, that is, an AC component, a filter unit for detecting only a DC component from the light reception signal, and the surroundings of the LED light emitting unit. A reference voltage unit that outputs a reference signal according to a temperature change is compared with an output of the filter unit and an output reference signal of the reference voltage unit, and a control signal is output to the LED light emitting unit. A comparing unit, in which as each input signal constituted by an arithmetic processing unit for performing based on calculation processing corrects the modulation error due to the peak wavelength variation of the LED light emission unit.

[0010]

According to the above construction, the reference signal value of the reference voltage section is changed in real time according to the ambient temperature of the LED light emitting section obtained by the temperature detecting section, so that the LED light emitting section control signal by the comparing section becomes the reference value. Since the control signal value is proportional to the signal value, the light emission amount in the LED light emitting part is adjusted, and the sensor signal error due to the peak wavelength fluctuation of the LED light emitting part due to the temperature change is corrected and the modulated signal is constantly measured current value or voltage. The value is proportional to the value. Further, the DC component detected by the filter unit and input to the comparison unit is
The control signal to the LED light emitting section is adjusted to correct the error in the light receiving modulation signal due to the light emitting characteristics of the LED light emitting section and other factors that change the light amount.

[0011]

EXAMPLE An optical applied current voltage sensor LED of the present invention will be described below.
One embodiment of the control circuit is shown in FIG. 1 and will be described. In FIG. 1, the same parts as those in FIG. 5 are designated by the same reference numerals, and the description will be omitted and different parts will be described.

The optical applied current voltage sensor LED control circuit of the present invention uses the optical fiber 1 to output the light amount signal from the LED light emitting section 8.
0 is transmitted, the optical sensor 11 converts it into an optical modulation signal proportional to the current value or the voltage value of the electric line, and the optical fiber 10 inputs it to the light receiving unit 1. FIGS. 2A and 2B show waveforms of the light emission amount P _o from the LED light emitting portion 8 and the light reception amount P _i received by the light receiving portion 1 converted by the optical sensor 11. In FIG. 2B, P _id is a DC component of the light modulation signal, and P _ia is an AC component which is the modulation component of the light modulation signal. The light modulation signal received by the light receiving unit 1 is converted into an electric signal, only the DC component is detected by the filter unit 3, and the reference voltage value output from the reference voltage unit 7 is compared with the comparison unit 6 to the LED light emitting unit 8. A control signal is output so that the error of the light reception modulation signal is corrected with respect to the light emission characteristics of the LED light emitting unit 8 and other various light amount change factors.
The control signal to the ED light emitting unit 8 is adjusted.

When current measurement is performed by the optical applied current / voltage sensor configured as described above, the light reception signal P _i is approximately represented by the following equation.

P _i = α × P _o × (1 + 2 × V × H × L) (1) where α is a loss coefficient, P _o emission amount, V is a Verdet constant,
H is the strength of the magnetic field generated by the current flowing in the electric line, and L is the length of the sensor element (Faraday element).

The light receiving section 1 converts the modulated signal P _i into an electric signal, and the amplifying section 2 includes P _ia = α × P _o × 2 × V × H × L ... (2) That is, only the modulation component is amplified and the arithmetic processing is performed as a current signal.

Next, FIGS. 3 and 4 show changes in the LED peak wavelength deviation with respect to changes in the ambient temperature of the LED light emitting section 8 and changes in the Verdet constant (sensor sensitivity) with respect to changes in the LED peak wavelength. As is clear from FIGS. 3 and 4, when the light emission control is performed only by comparing the received light DC component, that is, P _id = α × P _o (3) with the reference value, L
Since the LED peak wavelength fluctuates and the sensor sensitivity changes due to the change in the ambient temperature of the ED light emitting unit 8, an error occurs in the output. In this case, the sensor output decreases with increasing temperature, so the modulation output decreases. Therefore, by correcting and controlling the reference signal level of the reference voltage unit 7 to increase with respect to the temperature rise in accordance with the sensor sensitivity change with respect to the ambient temperature change of the LED light emitting unit 8, the control signal of the LED light emitting unit 8 is also changed. Since the light emission amount increases in proportion to the reference signal level of the reference voltage unit 7, the P _ia shown in Formula (2), that is, the modulation component also increases, and the sensor sensitivity error with respect to the ambient temperature of the LED light emitting unit 8 is corrected. Done.

Also, when the voltage is measured by the optical current voltage sensor, as in the case where the Verdet constant for the ambient temperature change of the LED light emitting section 8 is corrected in the current measurement, the Pockels constant for the LED peak wavelength change is corrected. By performing the above correction, the voltage can be measured without being affected by the ambient temperature of the LED light emitting unit 8 by using the same circuit configuration as that in the current measurement.

According to the configuration of the present invention, since the correction coefficient for the ambient temperature of the LED light emitting section 8 is not used,
There is no error due to the minimum resolution of the correction coefficient,
Further, it does not require a memory for storing the correction coefficient, does not require arithmetic processing for multiplication of the measurement signal, and does not require a complicated processing program. Further, there is no need to increase the size and complexity of the device as in the configuration for adjusting the ambient temperature of the LED light emitting section 8.

[0019]

As is apparent from the above description, according to the optical applied current voltage sensor LED control circuit of the present invention, the current measurement is performed in the optical type current voltage measuring device using the optical applied current voltage sensor LED control circuit. The LED light emission part control signal is corrected in real time according to the change of the Verdet constant due to the change of the ambient temperature of the LED light emission part and the change of the Pockels constant due to the change of the ambient temperature of the LED light emission part at the time of voltage measurement. The sensor sensitivity error due to the ambient temperature of the part can be eliminated. Further, by inputting only the direct current component of the light receiving unit output to the comparing unit by the filter unit, the LED light emitting unit can obtain a constant light receiving modulation signal with respect to the light emitting characteristics of the LED light emitting unit and various other light amount change factors. Since the control signal is corrected, the current or voltage can be measured with high accuracy with a simple circuit configuration. Further, the optical application current voltage sensor LED of the present invention
If an optical current / voltage measuring device that uses a control circuit is adopted as an optical zero-phase current / voltage detector that detects the current value or voltage value of an electric line and monitors the condition of the electric line, it will be affected by the ambient temperature. Highly accurate measurement is possible.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of an optical applied current voltage sensor LED control circuit of the present invention.

FIG. 2A is a characteristic diagram showing a light emission waveform of an LED light emitting portion, and FIG. 2B is a characteristic diagram showing a light receiving waveform of a light receiving portion.

FIG. 3 is a characteristic diagram showing changes in the LED peak wavelength deviation with respect to changes in the ambient temperature of the LED light emitting section.

FIG. 4 is a characteristic diagram showing changes in Verdet constant with respect to changes in LED peak wavelength.

FIG. 5 is a block diagram of a conventional optical applied current voltage sensor LED control circuit.

[Explanation of symbols]

 1 Light-receiving part 2 Amplifying part 3 Filter part 4 Arithmetic processing part 6 Comparing part 7 Reference voltage part 8 LED light emitting part 9 Temperature detecting part 11 Optical sensor 12 Electrical line

Claims (1)

[Claims] 1. An LED light emitting section for converting an electric signal into a light quantity, a temperature detecting section for detecting an ambient temperature of the LED light emitting section, and a light in which a current value or a voltage value of an electric line is proportional to the current value or the voltage value. An optical sensor utilizing the Faraday effect by the electric field for converting into a modulated signal or the Pockels effect by the electric field, a light receiving section for converting an optical modulated signal into an electric signal, and an amplifying section for amplifying only the modulation component of the received light signal, that is, an AC component, The filter unit that detects only the DC component from the received light signal, the reference voltage unit that outputs the reference signal according to the ambient temperature change of the LED light emitting unit, and the output of the filter unit and the output reference signal of the reference voltage unit are compared. Compensation of modulation error due to peak wavelength variation of LED light emitting unit, which is composed of a comparing unit that outputs a control signal to the light emitting unit and an arithmetic processing unit that performs arithmetic processing based on each input signal. Applied Optics current voltage sensor LE performing
D control circuit.