JPH08170973A - Voltage sensor circuit - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a voltage sensor circuit capable of suppressing the influence of the external environment by making it possible to use a resistance element having a relatively low resistance value. A detector for inputting a measured DC voltage is connected to a first resistance element connected to one measured DC voltage output terminal and to the other measured DC voltage output terminal.
A second resistance element having the same resistance value as that of the second resistance element, and a third resistance element connected in series between the first resistance element and the second resistance element on the differential operation section side. In the voltage sensor circuit, the differential operation section differentially operates outputs of both ends of the third resistance element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage sensor circuit that suppresses the influence of characteristic changes of a resistance element and facilitates maintenance.

[0002]

2. Description of the Related Art FIG. 10 is an electric circuit diagram showing a configuration of a voltage sensor circuit of a thyristor Leonard device used for controlling a DC motor, for example. In the figure, TH1 to TH6 are thyristors and constitute a converter 1 having AC input terminals U, V, W and DC output terminals P, N. Reference numeral 2 is a voltage sensor circuit for measuring the DC output voltage of the converter 1. The voltage signal measured and output by the voltage sensor circuit 2 is used as a signal for controlling the converter 1 or for other purposes / applications.

The voltage sensor circuit 2 comprises a detector 2A and a differential calculator 2B. The detection unit 2A is provided between the DC output terminals P and N and the differential operation unit 2B, and has a resistance R.
A resistor circuit composed of X1 and a resistor RX2,
The resistance values of the resistors RX1 and RX2 are equal. Detector 2
The terminal T1 on the input side of A is connected to the DC output terminal P of the converter 1, and the terminal T2 is connected to the DC output terminal N of the converter 1. The differential operation unit 2B includes a differential operation amplifier OP and resistors R4, R5, R6, R7, R externally attached to the periphery thereof.
8 and includes an input terminal T of the differential operation section 2B.
5 is connected to the output side terminal T3 of the detection section 2A, and the input terminal T6 of the differential operation section 2B is connected to the output side terminal T4 of the detection section 2A.

In this case, the detector 2A is provided near the converter 1 and is easily affected by the external environment. Further, since the differential operation unit 2B is mounted on a printed circuit board or the like, it is relatively insensitive to the external environment.

FIG. 11 is a numerical explanatory diagram showing variations in voltage and current of each part in the practical constant selection example of the resistance element of the voltage sensor circuit shown in FIG. 10, which is caused by a bad surrounding environment such as salt damage. Then, the output voltage value of the voltage sensor circuit that fluctuates when the resistance element leaks and its resistance value changes is also shown.

According to FIG. 11, the output voltage value of the converter 1 is 440 volts (the output voltage value of the DC output terminal P is 220 volts and the output voltage value of the DC output terminal N is -220 volts).
At this time, the output voltage value of the voltage sensor circuit 2 is -5.5 V, and this output voltage value is the normal value.

Here, the resistors RX1 and RX2 of the detector 2A
If a leak of 10 meg ohms occurs at 1 and the equivalent resistance value fluctuates to 1150 kilo ohms, the voltage sensor circuit 2
Output voltage value of -6.069 V, which is apparently increased by 10.3% in absolute value compared to the normal value, and this value is regarded as an abnormal value.

[0008]

Since the conventional voltage sensor circuit is constructed as described above, the resistance values of the resistors RX1 and RX2 forming the detecting portion 2A are easily influenced by the surrounding environment and fluctuate. As a result, there is a problem that the output voltage of the voltage sensor circuit 2 fluctuates.

There is also a problem that it is not easy to inspect the voltage sensor circuit 2 when the resistance value of the resistance element changes.

Furthermore, since the resistance value of each resistance element of the voltage sensor circuit 2, particularly the resistance element of the detection circuit is relatively high, there is a problem that the selection of parts is limited.

The present invention has been made to solve the above-mentioned problems, and a voltage sensor circuit capable of reducing the influence of the external environment is obtained by making it possible to use a resistance element having a relatively low resistance value. The purpose is to

Another object of the present invention is to obtain a voltage sensor circuit which can easily inspect whether it is functioning normally.

[0013]

A voltage sensor circuit according to the invention of claim 1 is connected to a first resistance element connected to one measured DC voltage output terminal and to the other measured DC voltage output terminal. A second resistance element having a resistance value equal to the resistance value of the first resistance element, and a third resistance connected in series between the first resistance element and the second resistance element on the differential operation section side. A detection unit is configured by the element and the differential operation unit is configured to perform differential operation on the outputs of both ends of the third resistance element.

A voltage sensor circuit according to the invention of claim 2 is
The resistance values of the first resistance element and the second resistance element are set to the same value, and the resistance values of the first resistance element, the second resistance element, and the third resistance element are set to approximately 100 kilohms or more. The range is set to several hundred kilohms or less.

The voltage sensor circuit according to the invention of claim 3 is
The detection unit is connected to a measured DC voltage output terminal that outputs the measured DC voltage, or connected to a reference voltage source that generates a reference voltage. It was done.

The voltage sensor circuit according to the invention of claim 4 is
The power supply voltage of the power supply for operating the differential operation unit is used as a reference voltage.

The voltage sensor circuit according to the invention of claim 5 is
A differential operation section switching means for selecting either the output of both ends of the third resistance element or the reference voltage source output and supplying it to the differential operation section is provided.

A voltage sensor circuit according to the invention of claim 6 is
The reference voltage source selected by the differential operation section switching means uses the power supply voltage of the power supply for operating the differential operation section.

The voltage sensor circuit according to the invention of claim 7 is
An alternative reference voltage source for generating a reference voltage, voltage detection means for detecting the potential level of each part with reference to the neutral point potential of the alternative reference voltage source, and one reference voltage output terminal of the alternative reference voltage source. And a fifth resistance element connected to the other reference voltage output terminal of the alternative reference voltage source, and the fourth resistance element and the fifth resistance element on the differential operation section side. Sixth connected in series with the resistance element of
And a switching means for switching to the alternative reference voltage source and the alternative detection section, or for switching to the alternative reference voltage source.

The voltage sensor circuit according to the invention of claim 8 is
Whether the detection unit including the first resistance element and the second resistance element is connected to the measured DC voltage output terminal that outputs the measured DC voltage or the reference voltage source that generates the reference voltage The detection unit switching means for selecting either one is provided.

A voltage sensor circuit according to a ninth aspect of the invention is
The reference voltage source selected by the detection unit switching means uses the power supply voltage of the power supply for operating the differential operation unit.

According to a tenth aspect of the present invention, in the voltage sensor circuit, either the output of the detection section formed of the first resistance element and the second resistance element or the reference voltage source output is selected and supplied to the differential operation section. It is provided with a differential operation section switching means for the purpose.

According to another aspect of the voltage sensor circuit of the present invention, there is provided an alternative reference voltage source for generating a reference voltage, and voltage detection for detecting the potential level of each part with reference to the neutral point potential of the alternative reference voltage source. And a third resistance element connected to one reference voltage output terminal of the alternative reference voltage source and a fourth resistance element connected to the other reference voltage output terminal of the alternative reference voltage source. Detecting section, the measured DC voltage output from the measured DC voltage output terminal is replaced with the reference voltage output by the alternative reference voltage source, and the detecting section is replaced with the alternative detecting section, or the measured DC voltage A switching means for substituting the measured DC voltage output from the output terminal for the reference voltage output by the alternative reference voltage source is provided.

[0024]

In the detector of the invention of claim 1, the third resistance element is inserted in series between the first resistance element and the second resistance element having the same resistance value on the differential operation section side, Since the constants of the first resistance element and the second resistance element can be set to values lower than conventional values, the first resistance element and the second resistance element due to the external environment, and further the third resistance element. The ratio of the influence on the output of the differential operation unit is reduced due to the change in the characteristic of, and the error appearing in the measurement result is reduced.

According to a second aspect of the present invention, the detection section sets the resistance values of the first resistance element and the second resistance element to the same value, and the first resistance element and the second resistance element.
And the resistance value of the third resistance element is approximately 10
By setting the range of 0 kilohms or more to several hundreds of kilohms or less, the influence of the first resistance element and the second resistance element, which are set to values lower than those of the related art, on the output of the differential operation unit is suppressed.

According to the third aspect of the invention, the detecting section switching means switches the connection of the detecting section to either the measured DC voltage output terminal side for outputting the measured DC voltage or the reference voltage source side for generating the reference voltage. It is possible to measure the reference voltage generated by the reference voltage source and facilitate the inspection and confirmation of whether the voltage sensor circuit is operating normally.

In the detector switching means in the invention of claim 4, the detector is connected to either the measured DC voltage output terminal side from which the measured DC voltage is output or the power supply side for operating the differential operation section. Switching is enabled, and a power supply voltage for operating the differential operation unit is measured as a reference voltage source to facilitate inspection and confirmation whether the voltage sensor circuit is operating normally.

According to the fifth aspect of the present invention, the differential operation section switching means selects either the output of both ends of the third resistance element or the reference voltage source output and supplies it to the differential operation section. By switching to, it becomes easy to check and confirm whether or not the differential operation unit is operating normally.

According to the sixth aspect of the present invention, the differential operation section switching means selects either the output across the third resistance element or the power supply voltage output of the power supply for operating the differential operation section to perform the differential operation. The power supply voltage for operating the differential operation section is measured to facilitate inspection and confirmation of whether the differential operation section is operating normally.

According to a seventh aspect of the voltage sensor circuit of the present invention, an alternative reference voltage source for generating a reference voltage, and a voltage detecting means for detecting the potential level of each part with reference to the neutral point potential of the alternative reference voltage source. A fourth resistance element connected to one of the reference voltage output terminals of the alternative reference voltage source, a fifth resistance element connected to the other reference voltage output terminal of the alternative reference voltage source, and a differential operation A sixth side connected in series between the fourth resistance element and the fifth resistance element
Whether a voltage sensor circuit, a detection unit of the voltage sensor circuit, or a differential operation unit is operating normally by separately providing an alternative detection unit composed of a resistance element and switching to the alternative reference voltage source or the alternative detection unit. Make it easy to confirm the inspection.

According to a eighth aspect of the present invention, there is provided a detection section switching means which includes a detection section including a first resistance element and a second resistance element, which is connected to a measured DC voltage output terminal for outputting a measured DC voltage or a reference voltage. One of the generated reference voltage sources is selected, and the reference voltage generated by the reference voltage source is measured to facilitate the inspection and confirmation of whether the voltage sensor circuit is operating normally.

According to a ninth aspect of the present invention, the detecting section switching means connects the detecting section to either the measured DC voltage output terminal side from which the measured DC voltage is output or the power source side for operating the differential operation section. Switching is enabled, and a power supply voltage for operating the differential operation unit is measured as a reference voltage source to facilitate inspection and confirmation whether the voltage sensor circuit is operating normally.

According to the tenth aspect of the present invention, the differential operation section switching means can select either the output of the detection section composed of the first resistance element and the second resistance element or the reference voltage source output for generating the reference voltage. By measuring the reference voltage, it becomes easy to check and confirm whether the differential operation unit is operating normally.

According to the eleventh aspect of the present invention, in the voltage sensor circuit, an alternative reference voltage source for generating a reference voltage, and voltage detection means for detecting the potential level of each part with reference to the neutral point potential of the alternative reference voltage source. And a fourth resistance element connected to one reference voltage output terminal of the alternative reference voltage source and a fifth resistance element connected to the other reference voltage output terminal of the alternative reference voltage source. By providing a separate section and switching to the alternative reference voltage source or the alternative detection section, it becomes easy to perform inspection and confirmation whether the voltage sensor circuit, the detection section of the voltage sensor circuit, or the differential operation section is operating normally. .

[0035]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an electric circuit diagram showing the configuration of the voltage sensor circuit of the first embodiment. In FIG. 1, parts that are the same as or correspond to those in FIG.
In the figure, RY is a DC output terminal P and a DC output terminal N
Of the resistor (first resistance element) RX1 and the resistance (second resistance element) RX2 connected to the respective elements of the differential operation unit 2B side, and the third resistance element connected in series to the resistors RX1 and RX2. is there.

Next, the operation will be described. Now, if the voltage (potential with respect to neutral potential) in each part of the circuit and the current flowing through each resistance of the circuit are set as shown in the figure, the following equations hold. The resistance RX of the detection unit
1 and RX2 are RX1 = RX2 = RX.

EP-E1 = [(E1-E2) / RY + {E1-E2 * R7 / (R5 + R7)} / R4] * RX ... (1) E2-EN = [(E1-E2) / RY-E2 / (R5 + R7)] × RX (2) E3 = E4 (3) E4 = E2 × R7 / (R5 + R7) (4) E1-E3 = I4 × R4 ... (5) I8 = (E3-E0) / R8 ... (6) I6 = E3 / R6 ... (7)

Here, the potentials EP, EN, E0 and the third
The values of the resistors RX1 and RX2 can be obtained by solving the equations (1) to (7) with the resistance element RY and the resistors R4, R5, R6, R7, and R8 of FIG.

Potentials EP, EN, E0 and resistors R4, R
The values of 5, R6, R7 and R8 are practical values, that is,
The resistors R4 and R5 have the same value, 300 KΩ, the resistor R6 is 20 KΩ, the resistor R7 is 10 KΩ, and the resistor R8 is 2.
0KΩ, potential EP is 220V, potential EN is -220V,
When the potential E0 is set to -5.5V, the resistances RX1 and R
When the relationship between X2 and the third resistance element RY is obtained, the result as shown in FIG. 2 is obtained.

Next, the potential (output voltage of the differential operation section 2B) E0 and its reference value when it is assumed that leaks of 10 megohms occur in the resistors RX1 and RX2 and the third resistance element RY due to salt damage and the like, respectively. (-5.5V)
If the error with respect to is changed, the result shown in FIG. 3 is obtained.

That is, the selection range of the third resistance element RY is 100 KΩ to 600 KΩ, and the resistors RX1 and RX2 are set to 1.
From 85 KΩ to 650 KΩ, it is found that the error generated in the output voltage E0 falls within the range of 1.0% to 2.78%. This result is clearly smaller than the error that occurs in the output voltage of the conventional voltage sensor circuit shown in FIG.

As described above, in the conventional voltage sensor circuit, when the resistors RX1 and RX2 leak and the equivalent resistance value decreases, the error of the output voltage E0 is 10.3% of the normal value.
On the other hand, in the present embodiment, while the constants of the respective resistance elements of the differential operation unit 2B are set to the same condition, the constant is 1.0% in the present embodiment.
To 2.78%, it is possible to obtain accurate measurement results even if a leak occurs in the resistance element of the detection unit due to the external environment.

Example 2. Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 is an electric circuit diagram showing the configuration of the voltage sensor circuit of the second embodiment. 4, the same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. In the figure, 11 is a positive-side power supply voltage output terminal for outputting the positive-side power supply voltage of the differential operation unit 2B, and 12 is the differential operation unit 2
This is a negative electrode side power supply voltage output terminal to which the negative electrode side power supply voltage of B is output. Reference numeral 13 denotes a first detection unit switching means (detection unit switching means) having a first fixed electrode 13a connected to the DC output terminal P and a second fixed electrode terminal 13b connected to the positive power supply voltage output terminal 11. is there. The first detection unit switching means 13 includes a first fixed electrode 13a or a second fixed electrode 13
The movable contact moves to b, and the common contact 13c and the first fixed electrode 1
3a or the second fixed electrode 13b is electrically connected. The common contact 13c is connected to one end of the resistor RX1 of the detector 2A.

Reference numeral 14 denotes a second detecting portion switching means (detecting portion switching means) having a first fixed electrode 14a connected to the DC output terminal N and a second fixed electrode terminal 14b connected to the negative power supply voltage output terminal 12. Means). The second detection unit switching means 14 includes the first fixed electrode 14a or the second fixed electrode 14a.
The movable electrode moves to b, and the common contact 14c and the first fixed electrode 1
4a or the second fixed electrode 14b is electrically connected. The common contact 14c is connected to one end of the resistor RX2 of the detector 2A.

Next, the operation will be described. The first detection unit switching means 13 is switched, and the common contact 1 is made by the movable electrode.
3c and the first fixed electrode 13a are electrically connected, and the second detection unit switching means 14 is switched to electrically connect the common contact 14c and the first fixed electrode 14a by the movable electrode. The section 2A is connected to the DC output terminal P and the DC output terminal N, and measures the output voltage of the converter 1 applied to the DC output terminal P and the DC output terminal N.

Further, the first detecting portion switching means 13 is switched so that the common electrode 13c and the second fixed electrode 1 are moved by the movable electrode.
3b is electrically connected to the second detection unit switching means 1
4 is switched and the common contact 14c and the second fixed electrode 14b are electrically connected by the movable electrode, the detection unit 2
A is connected to the positive side power supply voltage output terminal 11 and the negative side power supply voltage output terminal 12 of the differential operation unit 2B. Since the voltage output from the positive-side power supply voltage output terminal 11 and the negative-side power supply voltage output terminal 12 of the differential operation unit 2B is a stabilized voltage whose output voltage value is clear in advance, it should be used as a reference voltage. Since it is possible to predict the output voltage of the voltage sensor circuit at this time, it is possible to know whether the voltage sensor circuit is operating normally by determining whether or not it matches the predicted value.

Example 3. Embodiments of the present invention will be described below with reference to the drawings. FIG. 5 is an electric circuit diagram showing the configuration of the voltage sensor circuit of the third embodiment. 5, the same parts as those in FIG. 4 are designated by the same reference numerals and the description thereof will be omitted. In the figure, 15 is a first fixed electrode 15a connected to one output terminal of the detection unit 2A and a positive-side power supply voltage output terminal 11
And a second fixed electrode terminal 15b connected to the first differential arithmetic unit switching means (differential arithmetic unit switching means). In this first differential operation unit switching means 15, the movable contact moves to the first fixed electrode 15a or the second fixed electrode 15b, and the common contact 15c and the first fixed electrode 15a or the second fixed electrode 1
5b is electrically connected. The common contact 15c is connected to one terminal of a resistor R4 connected to the inverting input terminal side of the differential operation amplifier OP of the differential operation section 2B.

Reference numeral 16 denotes a first fixed electrode 16a connected to the other output terminal of the detection section 2A and a negative-side power supply voltage output terminal 1
Second having a second fixed electrode terminal 16b connected to the second
It is a differential operation part switching means (differential operation part switching means). The second differential operation section switching means 16 includes a first fixed electrode 16a.
Alternatively, the movable contact moves to the second fixed electrode 16b to electrically connect the common contact 16c and the first fixed electrode 16a or the second fixed electrode 16b. The common contact 16c is connected to one terminal of a resistor R5 connected to the non-inverting input terminal side of the differential operation amplifier OP of the differential operation section 2B.

Next, the operation will be described. The first detection unit switching unit 13, the second detection unit switching unit 14, the first differential operation unit switching unit 15, and the second differential operation unit switching unit 16 are switched, and the circuit configuration shown in FIG. 5 is obtained. 2A, the detection unit 2A detects the DC output terminal P and the DC output terminal N.
The output voltage of the converter 1 is measured from the DC output terminal P and the DC output terminal N.

Further, the first differential operation section switching means 15 is switched to electrically connect the common contact 15c and the second fixed electrode 15b by the movable electrode, and the second differential operation section switching means 16 is switched. Common contact 1 by movable electrode
When 6c and the second fixed electrode 16b are electrically connected,
The differential operation unit 2B is connected to the positive power supply voltage output terminal 11 and the negative power supply voltage output terminal 12. Since the voltage output from the positive-side power supply voltage output terminal 11 and the negative-side power supply voltage output terminal 12 of the differential operation unit 2B is a stabilized voltage whose output voltage value is clear in advance, it should be used as a reference voltage. Since the output voltage of the differential operation unit 2B at this time can be predicted, it is possible to know whether the differential operation unit 2B is operating normally by determining whether the output voltage matches the predicted value. It is possible.

Embodiment 4 FIG. Embodiments of the present invention will be described below with reference to the drawings. FIG. 6 is an electric circuit diagram showing the configuration of the voltage sensor circuit of the fourth embodiment. 6, parts that are the same as those in FIG. 5 are given the same reference numerals, and descriptions thereof will be omitted. In the figure, 17 is a first detection unit switching means (switching means) for switching the connection to one input terminal of the detection unit 2A to the DC output terminal P side or the reference voltage source (alternative reference voltage source) 21 side, Is a second detector switching means (switching means) for switching the connection to the other input terminal of the detector 2A to the DC output terminal N side or the reference voltage source (alternative reference voltage source) 22 side. Reference numeral 19 denotes the connection of the resistor R4 of the differential operation unit 2B to one terminal of the resistor RX1 of the detection unit 2A and the third resistance element RY, or the resistance of the alternative detection unit 3A (the fourth resistance element). ) First differential operation section switching means (switching means) for switching to the connection point side of RX01 and the resistance (sixth resistance element) RY0, 20 is connected to one terminal of the resistance R5 of the differential operation section 2B. Connect the resistor RX2 of the detector 2A
And the third resistance element RY on the connection point side, or the resistance (fifth resistance element) RX02 and the resistance RY0 of the alternative detection unit 3A.
It is a second differential operation section switching means (switching means) for switching to the connection point side with. The alternative detection unit 3A uses the resistor R
It has the same configuration as the detection unit 2A composed of X1, RX2 and the third resistance element RY, and has a relationship of resistance RX1 = resistance RX2 = resistance RX01 = resistance RX02. Also, the resistance RY
The resistance value of 0 is also the same as that of the third resistance element RY. The reference voltage sources 21 and 22 generate a reference voltage, and 23 is a voltmeter (voltage detection means) for measuring the potential of each part with reference to the neutral point potential of the reference voltage sources 21 and 22. Reference numeral 3 is a reference unit, which includes the alternative detection unit 3A and the reference voltage source 2
1 and 22 and a voltmeter 23. In addition, 2b1 and 2b2 of the differential operation part 2B are terminals to be subjected to voltage measurement.

In this voltage sensor circuit, the first detection section switching means 17 and the second detection section switching means 18 are switched to the reference unit 3 side, and the first differential operation section switching means 19 is provided.
And the second differential operation section switching means 20 is connected to the voltage sensor circuit 2
When switched to the detection unit 2A side, the reference voltage sources 21 and 22 are supplied to the voltage sensor circuit 2, and the voltage sensor circuit 2 measures the reference voltage sources 21 and 22 and outputs the measurement result.

Further, the first detector switching means 17 and the second detector
The detection section switching means 18 was switched to the DC output terminal P and the DC output terminal N side, and the first differential operation section switching means 19 and the second differential operation section switching means 20 were switched to the reference unit 3 side. In this state, the reference voltage sources 21, 2
2 is supplied to the differential operation unit 2B via the alternative detection unit 3A of the reference unit, and the alternative detection unit 3A and the differential operation unit 2B of the reference unit 3 measure the reference voltage sources 21 and 22 and the measurement result. Is output.

By measuring the input voltage of the voltage sensor circuit 2 or the potential of each part such as the input voltage and the output voltage of the differential operation part 2B by the voltmeter 23 while performing each such switching operation. It is possible to know whether the detection unit 2A and the differential operation unit 2B, or the detection unit 2A or the differential operation unit 2B are operating normally.

Therefore, according to this embodiment, the first detector switching means 17 and the second detector switching means 18, the first differential operation portion switching means 19 and the second differential operation portion switching means 2 are provided.
By combining switching with 0, the voltage sensor circuit 2
It is possible to efficiently and surely check the operation of each of the detection unit 2A and the differential operation unit 2B.

Example 5. Embodiments of the present invention will be described below with reference to the drawings. FIG. 7 is an electric circuit diagram showing the configuration of the voltage sensor circuit of the fifth embodiment. In FIG. 7, the same or corresponding parts as those in FIG. 4 are designated by the same reference numerals and the description thereof will be omitted. However, the first detection part switching means 13 and the second detection part switching means 14 of the voltage sensor circuit of this embodiment are The wiring structure includes the same configuration as the first detection unit switching unit and the second detection unit switching unit used in the voltage sensor circuit according to the second embodiment illustrated in FIG. 4, and the configuration of the voltage sensor circuit. Is the same as the conventional one.

Also in this embodiment, similarly to the second embodiment, the first detection section switching means 13 and the second detection section switching means 14 are connected to the positive side power supply voltage output terminal 11 and the negative side power supply voltage of the differential operation section 2B. By switching to the output terminal 12 side, it is possible to know whether the voltage sensor circuit is operating normally. Since the conventional voltage sensor circuit is used, the number of parts is smaller than that of the voltage sensor circuit of the second embodiment. The function check of the voltage sensor circuit can be performed with a simpler circuit configuration.

Example 6. Embodiments of the present invention will be described below with reference to the drawings. FIG. 8 is an electric circuit diagram showing the configuration of the voltage sensor circuit of the sixth embodiment. In FIG. 8, the same or corresponding parts as those in FIG. 5 are designated by the same reference numerals and the description thereof will be omitted, but the first detection part switching means 13 and the second detection part switching means 14 of the voltage sensor circuit of this embodiment, and First
The differential operation part switching means 15 and the second differential operation part switching means 16, including the wiring relationship, are used in the voltage sensor circuit of the third embodiment shown in FIG.
The detection section switching means, the first differential operation section switching means, and the second differential operation section switching means have the same configuration, and the configuration of the voltage sensor circuit is the same as the conventional one.

Also in this embodiment, as in the third embodiment, the first differential operation section switching means 15 and the second differential operation section switching means 16 are connected to the positive power supply voltage output terminal 11 of the differential operation section 2B. By switching to the negative power supply voltage output terminal 12 side, it is possible to know whether the differential operation unit 2B is operating normally, and since the conventional voltage sensor circuit is used, the voltage sensor circuit of the third embodiment is used. It is possible to check the functions of the detection unit 2A and the differential operation unit 2B of the voltage sensor circuit 2 with a simpler circuit configuration having a smaller number of parts than the above.

Example 7. Embodiment 7 of the present invention will be described below with reference to the drawings. FIG. 9 is an electric circuit diagram showing the configuration of the voltage sensor circuit of this embodiment. In FIG. 9, parts that are the same as or equivalent to those in FIG. 6 are given the same reference numerals and explanations thereof are omitted, but the first detection part switching means 17 and the second detection part switching means 18 of the voltage sensor circuit of this embodiment, and The first differential operation section switching means 19, the second differential operation section switching means 20, and the reference unit 3 are shown in FIG.
The first detection section switching means, the second detection section switching means, the first differential operation section switching means, the second differential operation section switching means, and the reference unit used in the voltage sensor circuit of the fourth embodiment shown in FIG. The voltage sensor circuit has the same configuration, and the configuration of the voltage sensor circuit is the same as the conventional one.

Also in this embodiment, as in the case of the fourth embodiment, the first detector switching means 17 and the second detector switching means 18, the first differential operation portion switching means 19 and the second differential operation portion switching are performed. By combining the switching with the means 20, it is possible to efficiently and surely check the operation of each of the detection unit of the voltage sensor circuit and the differential operation unit 2B.

In this embodiment, particularly, when the conventional voltage sensor circuit shown in FIG. 10 is continuously used, the change of the circuit configuration is minimized, and the function check is easily performed. Alternatively, it is effective when it is difficult to additionally mount the third resistance element RY.

[0063]

As described above, according to the first aspect of the invention, the first resistance element in which the detection portion of the voltage sensor circuit is connected to one of the measured DC voltage output terminals, and the first resistance element And a second resistance element connected to the other of the measured DC voltage output terminals having the same resistance value, and in series between the first resistance element and the second resistance element on the differential operation side. Since the differential operation unit is configured to perform differential operation on outputs from both ends of the third resistance element, the influence of changes in the external environment on the measurement results. There is an effect that a voltage sensor circuit that can suppress the above can be obtained.

According to the second aspect of the present invention, the resistance values of the first resistance element and the second resistance element are set to the same value, and the first resistance element and the second resistance element are arranged on the differential operation section side. And a resistance value of the first resistance element and the second resistance element connected in series between the second resistance element and the third resistance element are set in a range of approximately 100 kilohms or more to several hundred kilohms or less. With this configuration, the rate of change in the resistance value of the first resistance element, the second resistance element, and the third resistance element due to leakage or the like becomes smaller than the normal value, and the influence on the measurement result is reduced. There is an effect that a voltage sensor circuit that can be reduced is obtained.

According to the third aspect of the present invention, the detection is switched to either one of the measured DC voltage output terminal side which outputs the measured DC voltage and the reference voltage source side which generates the reference voltage. Since it is configured to include the unit switching unit, there is an effect that a voltage sensor circuit that can easily perform an inspection as to whether the detection unit and the differential operation unit are functioning normally can be obtained.

According to the invention of claim 4, when the measured DC voltage output terminal side from which the measured DC voltage is output or the power supply voltage of the power supply for operating the differential operation section is used as the reference voltage source. Select one of the reference voltage source side,
Since the detection section switching means for switching the connection of the detection section is provided, whether the detection section and the differential calculation section are functioning normally based on the power supply voltage of the power supply for operating the differential calculation section. There is an effect that a voltage sensor circuit that can easily perform the inspection of whether or not it can be obtained.

According to the fifth aspect of the present invention, the differential operation section switching means for selecting either the output across the third resistance element of the detection section or the reference voltage source output and supplying it to the differential operation section. Since the differential calculation section switching means or the detection section switching means selects the reference voltage source output, it is determined whether the detection section or the differential calculation section is functioning normally. There is an effect that a voltage sensor circuit that can be easily tested is obtained.

According to the invention of claim 6, the power supply voltage of the power supply for operating the differential operation section is used as the reference voltage,
Since the differential operation section switching means for selecting either the output across the third resistance element of the detection section or the reference voltage and supplying it to the differential operation section is provided, the differential operation section is provided. There is an effect that a voltage sensor circuit can be obtained that can easily inspect whether the detection unit or the differential operation unit is functioning normally based on the power supply voltage of the power supply for operating the.

According to a seventh aspect of the present invention, one of the alternative reference voltage source and voltage detecting means for detecting the potential level of each part with reference to the neutral point potential of the alternative reference voltage source for generating the reference voltage. And a fifth resistance element connected to the other reference voltage output terminal of the alternative reference voltage source, and the fourth resistance element on the differential operation side. And a sixth resistance element connected in series between the fifth resistance element and the fifth resistance element, and the measured DC voltage output from the measured DC voltage output terminal to the alternative reference voltage source. Since it is configured to include a switching unit for substituting the detection unit with the substitution detection unit, the operation of each unit of the voltage sensor circuit is normally performed using the substitution reference voltage source and the voltage detection unit. You can easily determine whether or not Voltage sensor circuit is effective to obtain that.

According to the eighth aspect of the present invention, in the conventional voltage sensor circuit, the connection of the detecting portion is selected by switching to either the measured DC voltage output terminal side where the measured DC voltage is output or the reference voltage source side. Since the circuit configuration of the detection unit and the differential calculation unit is the same as that of the conventional circuit, the difference between when the connection of the detection unit is switched to the reference power source side by the detection unit switching unit is maintained. It is possible to obtain a voltage sensor circuit that can easily perform an inspection as to whether or not the detection unit and the differential operation unit are functioning normally, based on the measurement result output from the dynamic operation unit.

According to the invention of claim 9, the connection of the detection circuit is switched to either the measured DC voltage output terminal side from which the measured DC voltage is output or the power source side for operating the differential operation section. Since the detection unit switching unit for selecting is provided, the circuit configuration of the detection unit and the differential calculation unit is the same as before, and the detection unit switching unit operates the differential calculation unit by connecting the detection unit. Voltage sensor that can easily inspect whether the detection unit and the differential operation unit are functioning normally based on the measurement result output from the differential operation unit when the power supply side is switched to There is an effect that a circuit can be obtained.

According to the tenth aspect of the present invention, the difference for selecting either the output of the detection section formed of the first resistance element and the second resistance element or the reference voltage source output and supplying it to the differential operation section. Since the dynamic calculation unit switching means is provided, the circuit configuration of the detection unit and the differential calculation unit remains the same as before, and the reference voltage source output is selected by the differential calculation unit switching unit or the detection unit switching unit. Thus, it is possible to obtain a voltage sensor circuit that can easily perform an inspection as to whether the detection unit or the differential operation unit is functioning normally based on the measurement result output from the differential operation unit. effective.

According to the eleventh aspect of the present invention, one of the alternative reference voltage source and voltage detecting means for detecting the potential level of each part with reference to the neutral point potential of the alternative reference voltage source for generating the reference voltage. Of the fourth resistance element connected to the reference voltage output terminal and the fifth resistance element connected to the other reference voltage output terminal of the alternative reference voltage source, and a DC voltage output terminal to be measured. Since the DC voltage to be measured output from the substitute reference voltage source is substituted, and the detection unit is configured to include switching means for replacing the substitute detection unit, the circuit configuration of the detection unit and the differential operation unit. As in the prior art, there is an effect that it is possible to obtain a voltage sensor circuit that can easily determine whether or not the operation of each part of the voltage sensor circuit is normally performed by using the alternative reference voltage source and the voltage detecting means.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing a configuration of a voltage sensor circuit according to a first embodiment of the present invention.

FIG. 2 is a numerical explanatory diagram showing a relationship between a resistance value of a resistor RX and a resistance value of a third resistance element RY of the voltage sensor circuit according to the first embodiment of the present invention.

FIG. 3 is an output voltage value of the voltage sensor circuit when the resistance value of the resistor RX and the resistance value of the third resistance element RY of the voltage sensor circuit according to the first embodiment of the present invention fluctuate, and in a normal state. It is a numerical explanatory view showing the ratio of the error to the output voltage value.

FIG. 4 is an electric circuit diagram showing a configuration of a voltage sensor circuit according to a second embodiment of the present invention.

FIG. 5 is an electric circuit diagram showing a configuration of a voltage sensor circuit according to a third embodiment of the present invention.

FIG. 6 is an electric circuit diagram showing a configuration of a voltage sensor circuit according to a fourth embodiment of the present invention.

FIG. 7 is an electric circuit diagram showing a configuration of a voltage sensor circuit according to a fifth embodiment of the present invention.

FIG. 8 is an electric circuit diagram showing a configuration of a voltage sensor circuit according to a sixth embodiment of the present invention.

FIG. 9 is an electric circuit diagram showing a configuration of a voltage sensor circuit according to a seventh embodiment of the present invention.

FIG. 10 is an electric circuit diagram showing a configuration of a conventional voltage sensor circuit.

FIG. 11 is a numerical explanatory diagram showing numerically the state in which the potential and current of each part change when the resistance RX changes in the conventional voltage sensor circuit.

[Explanation of symbols]

P, N DC output terminals (measured DC voltage output terminals), 2
Voltage sensor circuit, 2A detection unit, 2B differential operation unit,
RX1 resistance (first resistance element), RX2 resistance (second resistance element)
Resistance element), RY third resistance element, 13 first detection section switching means (detection section switching means), 14 second detection section switching means (detection section switching means), 15 first differential operation section switching means ( Differential operation section switching means), 16 second differential operation section switching means (differential operation section switching means), 17 first detection section switching means (switching means), 18 second detection section switching means (switching means), 19 First differential operation unit switching means (switching means), 2
0 Second differential operation unit switching means (switching means) 21, 22
Reference voltage source (alternative reference voltage source), 23 Voltmeter (voltage detection means), RX01 Resistance (fourth resistance element), RX0
2 resistance (5th resistance element), RY0 resistance (6th resistance element), 3A alternative detection part.

Claims (11)

[Claims] 1. An output of a detection unit connected to a measured DC voltage output terminal to which a measured DC voltage is applied is differentially calculated by a differential calculation unit, and a voltage output value that is the differential calculation result is used as a basis. In a voltage sensor circuit for measuring a measured DC voltage output from the measured DC voltage output terminal, a first resistance element connected to one measured DC voltage output terminal and the other measured DC voltage A second resistance element connected to the output terminal and having a resistance value equal to that of the first resistance element;
The detection unit is composed of a third resistance element that is connected in series between the first resistance element and the second resistance element on the side of the differential calculation unit, and the differential calculation unit includes the third resistance element. A voltage sensor circuit characterized by differentially calculating outputs of both ends of a third resistance element. 2. The first resistance element and the second resistance element have the same resistance value, and the first resistance element, the second resistance element and the third resistance element have the same resistance value. 2. The voltage sensor circuit according to claim 1, wherein the resistance value is set in the range of approximately 100 kohm or more to several hundred kohm or less. 3. A detection which selects either one of the detection unit connected to a measured DC voltage output terminal for outputting the measured DC voltage or a reference voltage source for generating a reference voltage. The voltage sensor circuit according to claim 1 or 2, further comprising a section switching means. 4. The voltage sensor circuit according to claim 3, wherein the reference voltage source uses a power supply voltage of a power supply for operating the differential operation unit. 5. A differential operation section switching means for selecting either the output across the third resistance element or the output of a reference voltage source for generating the reference voltage and supplying it to the differential operation section. The voltage sensor circuit according to claim 3, wherein: 6. The voltage sensor circuit according to claim 5, wherein the reference voltage source uses a power supply voltage of a power supply for operating the differential operation section. 7. The differential operation section differentially operates the output of the detection section connected to the measured DC voltage output terminal from which the measured DC voltage is output, and based on the voltage output value which is the differential operation result. In the voltage sensor circuit for measuring the measured DC voltage output from the measured DC voltage output terminal, an alternative reference voltage source for generating a reference voltage, and a neutral point potential of each part based on the neutral point potential of the alternative reference voltage source. Voltage detection means for detecting a potential level, a fourth resistance element connected to one reference voltage output terminal of the alternative reference voltage source, and another reference voltage output terminal of the alternative reference voltage source An alternative detection unit including a fifth resistance element and a sixth resistance element connected in series between the fourth resistance element and the fifth resistance element on the differential operation section side; The DC voltage output from the measured DC voltage output terminal The measured DC voltage is replaced by the reference voltage output by the alternative reference voltage source, and the detection unit is replaced by the alternative detection unit, or the measured DC voltage output from the measured DC voltage output terminal is the alternative reference. A switching means for substituting the reference voltage output from the voltage source, wherein the differential operation section differentially operates the output across the third resistance element or the output across the sixth resistance element. A voltage sensor circuit characterized by. 8. A first resistance element connected to a measured DC voltage output terminal for outputting a measured DC voltage and connected to one of the measured DC voltage output terminals, and the other of the measured DC voltage outputs. The output of the detection unit including the second resistance element connected to the terminal is differentially calculated by the differential calculation unit, and is output from the measured DC voltage output terminal based on the voltage output value that is the differential calculation result. In the voltage sensor circuit for measuring the measured DC voltage, the detector is connected to the measured DC voltage output terminal to which the measured DC voltage is output, or to the reference voltage source for generating the reference voltage. , A voltage sensor circuit comprising a detection unit switching means for selecting either one. 9. The voltage sensor circuit according to claim 8, wherein the reference voltage source uses a power supply voltage of a power supply for operating the differential operation section. 10. A differential operation for selecting either the output of a detection unit formed of the first resistance element and the second resistance element or the output of the reference voltage source and supplying the selected output to the differential operation unit. The voltage sensor circuit according to claim 8 or 9, further comprising a section switching means. 11. A first resistance element connected to a measured DC voltage output terminal for outputting a measured DC voltage and connected to one of the measured DC voltage output terminals, and the other of the measured DC voltage output. The output of the detection unit including the second resistance element connected to the terminal is differentially calculated in the differential calculation unit, and is output from the measured DC voltage output terminal based on the voltage output value that is the differential calculation result. In a voltage sensor circuit for measuring a DC voltage to be measured, an alternative reference voltage source for generating a reference voltage, and a voltage detecting means for detecting the potential level of each part with reference to the neutral point potential of the alternative reference voltage source. When,
An alternative detection unit including a third resistance element connected to one reference voltage output terminal of the alternative reference voltage source and a fourth resistance element connected to the other reference voltage output terminal of the alternative reference voltage source. , The measured DC voltage output from the measured DC voltage output terminal is replaced with the alternative reference voltage source and the detection unit is replaced with the alternative detection unit, or is output from the measured DC voltage output terminal. A voltage sensor circuit comprising switching means for substituting the measured DC voltage for the reference voltage output by the alternative reference voltage source.