JP2859545B2 - Voltage sensor circuit - Google Patents

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 which suppresses the influence of a change in the characteristics 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 denotes a voltage sensor circuit that measures 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 another purpose or application.

[0003] The voltage sensor circuit 2 comprises a detection section 2A and a differential operation section 2B. The detection unit 2A is provided between the DC output terminals P and N and the differential operation unit 2B, and includes a resistor R
X1 and a resistor RX2.
The resistance values of the resistor RX1 and the resistor 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
8 and the input terminal T of the differential operation unit 2B.
Reference numeral 5 is connected to an output terminal T3 of the detection unit 2A, and an input terminal T6 of the differential operation unit 2B is connected to an output terminal T4 of the detection unit 2A.

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

FIG. 11 is a numerical explanatory diagram showing fluctuations in the voltage and current of each part in the practical constant selection example of the resistance element of the voltage sensor circuit shown in FIG. In addition, the output voltage value of the voltage sensor circuit that fluctuates when a leak occurs in the resistance element and the resistance value changes is also shown.

According to FIG. 11, the output voltage of the converter 1 is 440 volts (the output voltage of the DC output terminal P is 220 volts, and the output voltage of the DC output terminal N is -220 volts).
In this case, the output voltage value of the voltage sensor circuit 2 is -5.5 volts, and this output voltage value is regarded as a normal value.

Here, the resistances RX1 and RX2 of the detection unit 2A
In the case where the leakage of 10 megohms occurs and the equivalent resistance value fluctuates to 1150 kohms, the voltage sensor circuit 2
Is -6.069 volts, an apparent increase of 10.3% in absolute value as compared with the normal value, and this value is regarded as an abnormal value.

[0008]

Since the conventional voltage sensor circuit is configured as described above, the resistance values of the resistors RX1 and RX2 constituting the detection unit 2A are easily affected 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 another 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 values of the resistance elements of the voltage sensor circuit 2, particularly the resistance elements of the detection circuit, are relatively high, there is a problem that the selection of parts is limited.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and a voltage sensor circuit capable of reducing the influence of an external environment 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 provide a voltage sensor circuit capable of easily checking whether or not it is functioning normally.

[0013]

According to a first aspect of the present invention, a voltage sensor circuit is connected to a first resistance element connected to one DC voltage output terminal to be measured and to the other DC voltage output terminal to be measured. A second resistance element having the same resistance value as 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 unit side A detection unit is constituted by the element and the differential operation unit is configured to perform a differential operation on outputs at both ends of the third resistance element.

According to a second aspect of the present invention, there is provided a voltage sensor circuit comprising:
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 about 100 kohm or more. The range is set to a range of several hundred kilohms or less.

According to a third aspect of the present invention, there is provided a voltage sensor circuit comprising:
The detection unit may be connected to a measured DC voltage output terminal from which a measured DC voltage is output, or may be connected to a reference voltage source that generates a reference voltage. It was done.

According to a fourth aspect of the present invention, there is provided a voltage sensor circuit comprising:
The power supply voltage of a power supply for operating the differential operation unit is used as a reference voltage.

According to a fifth aspect of the present invention, there is provided a voltage sensor circuit comprising:
A differential operation unit switching means for selecting either the output at both ends of the third resistance element or the output of the reference voltage source and supplying it to the differential operation unit is provided.

According to a sixth aspect of the present invention, there is provided a voltage sensor circuit comprising:
The reference voltage source selected by the differential operation unit switching means uses a power supply voltage of a power supply for operating the differential operation unit.

According to a seventh aspect of the present invention, a voltage sensor circuit comprises:
An alternative reference voltage source for generating a reference voltage, voltage detecting means for detecting a potential level of each part with reference to a neutral point potential of the alternative reference voltage source, and one reference voltage output terminal of the alternative reference voltage source And a fifth resistor connected to the other reference voltage output terminal of the alternative reference voltage source, and the fourth resistor and the fifth resistor on the differential operation unit side. The sixth element connected in series between the
And a switching unit for switching to the alternative reference voltage source and the alternative detection unit or for switching to the alternative reference voltage source.

The voltage sensor circuit according to the invention of claim 8 is:
Whether to connect the detection unit including the first resistance element and the second resistance element to a DC voltage output terminal to which a DC voltage to be measured is output, or to a reference voltage source that generates a reference voltage , A detecting unit switching means for selecting either one of them.

According to a ninth aspect of the present invention, there is provided a voltage sensor circuit comprising:
The reference voltage source selected by the detection unit switching means uses a power supply voltage of a power supply for operating the differential operation unit.

According to a tenth aspect of the present invention, the voltage sensor circuit selects either the output of the detection unit including the first resistance element and the second resistance element or the reference voltage source output and supplies the output to the differential operation unit. And a differential operation unit switching means.

According to a eleventh aspect of the present invention, there is provided a voltage sensor circuit comprising: an alternative reference voltage source for generating a reference voltage; and a voltage detection circuit for detecting a potential level of each part based on a neutral point potential of the alternative reference voltage source. Means, 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. A detection unit, which substitutes the measured DC voltage output from the measured DC voltage output terminal with the reference voltage output by the alternative reference voltage source and replaces the detecting unit with the substitute detecting unit, or the measured DC voltage There is provided switching means for replacing the measured DC voltage output from the output terminal with the reference voltage output from the alternative reference voltage source.

[0024]

According to a first aspect of the present invention, in the detection section, 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 lower values than in the past, the first resistance element, the second resistance element, and the third resistance element depending on the external environment The ratio of the influence on the output of the differential operation unit due to the change in the characteristic becomes small, and the error appearing in the measurement result decreases.

According to a second aspect of the present invention, the detecting section sets the resistance values of the first resistance element and the second resistance element to the same value, and sets the first resistance element and the second resistance element to the same value.
The resistance value of the third resistance element and the resistance value of
By setting the value in the range from 0 kOhm or more to several 100 kOhm or less, the influence on the output of the differential operation unit by the first resistance element and the second resistance element set to lower values than in the related art is suppressed.

According to a third aspect of the present invention, the detecting section switching means switches the connection of the detecting section to either a measured DC voltage output terminal side to which a measured DC voltage is output or a reference voltage source side to generate a reference voltage. And makes it easy to check and confirm whether the voltage sensor circuit is operating normally by measuring the reference voltage generated by the reference voltage source.

According to a fourth aspect of the present invention, the detecting section switching means connects the detecting section to either the DC voltage output terminal to which the DC voltage to be measured is output or the power supply for operating the differential operation section. Switching can be performed, and a power supply voltage for operating the differential operation unit is measured as a reference voltage source to easily check whether the voltage sensor circuit is operating normally.

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

According to a sixth aspect of the present invention, the differential operation unit switching means selects either the output at both ends of the third resistance element or the power supply voltage output of the power supply for operating the differential operation unit and performs the differential operation. The power supply voltage is supplied to the differential operation unit and the power supply voltage for operating the differential operation unit is measured, thereby facilitating the inspection and confirmation of whether or not the differential operation unit is operating normally.

According to a seventh aspect of the present invention, there is provided a voltage sensor circuit comprising: an alternative reference voltage source for generating a reference voltage; and a voltage detecting means for detecting a potential level of each part based on a neutral point potential of the alternative reference voltage source. 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; A sixth resistor connected in series between the fourth resistor and the fifth resistor on the unit side;
A separate detection unit consisting of a resistance element is separately provided, and by switching to these alternative reference voltage sources and alternative detection units, whether the voltage sensor circuit or the detection unit or the differential operation unit of the voltage sensor circuit is operating normally or not. Inspection is easily performed.

According to the eighth aspect of the present invention, the detecting section switching means includes a detecting section comprising a first resistive element and a second resistive element, which is connected to a DC voltage output terminal to be measured to output a DC voltage to be measured 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 easily check whether the voltage sensor circuit is operating normally.

According to the ninth aspect of the present invention, the detecting section switching means connects the detecting section to either the DC voltage output terminal to which the DC voltage to be measured is output or the power supply for operating the differential operation section. Switching can be performed, and a power supply voltage for operating the differential operation unit is measured as a reference voltage source to easily check whether the voltage sensor circuit is operating normally.

According to a tenth aspect of the present invention, the differential operation unit switching means can select either an output of the detection unit including the first resistance element and the second resistance element or a reference voltage source output for generating a reference voltage. By measuring the reference voltage, it is easy to check whether or not the differential operation section is operating normally.

According to the eleventh aspect of the present invention, there is provided a voltage sensor circuit comprising: an alternative reference voltage source for generating a reference voltage; and voltage detecting means for detecting a potential level of each part with reference to a 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. A separate section is provided, and switching to these alternative reference voltage sources and alternative detection sections facilitates inspection and confirmation as to whether the voltage sensor circuit or the detection section or differential operation section of the voltage sensor circuit is operating normally. .

[0035]

【Example】

Embodiment 1 FIG. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an electric circuit diagram illustrating the configuration of the voltage sensor circuit according to the first embodiment. In FIG. 1, the same or corresponding parts as those in FIG.
In the figure, RY is a DC output terminal P and a DC output terminal N
Are connected on the differential operation unit 2B side of the resistor (first resistor element) RX1 and the resistor (second resistor element) RX2, respectively, with the third resistor element connected in series to the resistors RX1 and RX2. is there.

Next, the operation will be described. Now, when the voltage (potential with respect to the 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 are established. In addition, the resistance RX of the detection unit
1, RX2 is set as 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) using the resistance element RY and the resistors R4, R5, R6, R7, and R8 as known numbers.

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

Next, the potential (output voltage of the differential operation unit 2B) E0 and its reference value when it is assumed that a leak of 10 megohms has occurred in the resistors RX1, RX2 and the third resistor RY due to salt damage or the like, respectively. (-5.5V)
The result shown in FIG. 3 is obtained by determining how the error with respect to changes.

That is, the selection range of the third resistance element RY is 100 KΩ to 600 KΩ, and the resistances RX1 and RX2 are 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 resistances RX1 and RX2 leak and the equivalent resistance value decreases, the error of the output voltage E0 becomes 10.3% of the normal value.
On the other hand, in the present embodiment, the constant of each resistance element of the differential operation unit 2B is increased by 1.0% with the same condition being set.
To 2.78%, and accurate measurement results can be obtained even if a leak occurs in the resistance element of the detection unit due to the external environment.

Embodiment 2 FIG. Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 4 is an electric circuit diagram illustrating a configuration of the voltage sensor circuit according to the second embodiment. In FIG. 4, the same portions as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. In the figure, reference numeral 11 denotes a positive power supply voltage output terminal for outputting a positive power supply voltage of the differential operation unit 2B, and 12 denotes a differential operation unit 2B.
This is a negative-side power supply voltage output terminal from which the negative-side power supply voltage of B is output. Reference numeral 13 denotes a first detection unit switching unit (detection unit switching unit) 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 13a.
b, the movable contact moves to 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 detection unit 2A.

Reference numeral 14 denotes a second detector switching means (detector switching) 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 detector switching means 14 is provided with a first fixed electrode 14a or a second fixed electrode 14a.
b, the movable electrode moves to 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 detection unit 2A.

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

Embodiment 3 FIG. Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 5 is an electric circuit diagram illustrating the configuration of the voltage sensor circuit according to the third embodiment. In FIG. 5, the same portions as those in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted. In the figure, reference numeral 15 denotes a first fixed electrode 15a connected to one output terminal of the detection unit 2A and a positive power supply voltage output terminal 11
And a second fixed electrode terminal 15b connected to the first differential operation unit switching means (differential operation unit switching means). The first differential operation unit switching means 15 is configured such that 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 unit 2B.

Reference numeral 16 denotes a first fixed electrode 16a connected to the other output terminal of the detection section 2A and a negative power supply voltage output terminal 1
2 having the second fixed electrode terminal 16b connected to the second fixed electrode terminal 16b.
It is a differential operation unit switching unit (differential operation unit switching unit). The second differential operation unit switching means 16 includes a first fixed electrode 16a.
Alternatively, the movable contact moves to the second fixed electrode 16b, and electrically connects the common contact 16c to 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 unit 2B.

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

Further, the first differential operation section switching means 15 is switched so that the common contact 15c and the second fixed electrode 15b are electrically connected by the movable electrode, and the second differential operation section switching means 16 is switched. Common contact 1
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 power supply voltage output terminal 11 and the negative power supply voltage output terminal 12 of the differential operation unit 2B is a stabilized voltage whose output voltage value is apparent in advance, it is used as a reference voltage. Since the output voltage of the differential operation unit 2B at this time can also be predicted, it can be determined whether the differential operation unit 2B is operating normally by determining whether or not the output voltage matches the predicted value. It is possible.

Embodiment 4 FIG. Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 6 is an electric circuit diagram illustrating the configuration of the voltage sensor circuit according to the fourth embodiment. In FIG. 6, the same portions as those in FIG. 5 are denoted by the same reference numerals, and description thereof will be omitted. In the figure, reference numeral 17 denotes 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 (alternate reference voltage source) 21 side; Is a second detection unit switching means (switching means) for switching the connection to the other input terminal of the detection unit 2A to the DC output terminal N side or the reference voltage source (alternate reference voltage source) 22 side. Reference numeral 19 denotes a connection between the resistor R4 of the differential operation unit 2B and one terminal of the resistance R4 of the detection unit 2A on the connection point side between the resistance RX1 and the third resistance element RY, or a resistance (the fourth resistance element ) A first differential operation unit switching means (switching means) for switching to a connection point side between RX01 and a resistance (sixth resistance element) RY0, and 20 is connected to one terminal of a resistor R5 of the differential operation unit 2B. Connect the connection to the resistor RX2 of the detection unit 2A.
(The fifth resistance element) RX02 and the resistance RY0 of the alternative detection section 3A, or the connection point side between the second detection element and the third resistance element RY.
The second differential operation unit switching means (switching means) for switching to the connection point side with the second differential operation unit. The replacement detection unit 3A is provided with the resistor R
It has the same configuration as the detection unit 2A including X1, RX2 and the third resistance element RY, and has a relationship of resistance RX1 = resistance RX2 = resistance RX01 = resistance RX02. The resistance RY
The resistance value of 0 is 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 detecting 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 denotes a reference unit, and the substitute detection unit 3A and the reference voltage source 2
1 and 22 and a voltmeter 23. Note that 2b1 and 2b2 of the differential operation unit 2B are voltage measurement terminals.

In this voltage sensor circuit, the first detector switching means 17 and the second detector switching means 18 are switched to the reference unit 3 side, and the first differential operation section switching means 19 is switched.
And the second differential operation unit switching means 20 is connected to the voltage sensor circuit 2
, 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.

The first detector switching means 17 and the second detector
With the detection unit switching unit 18 switched to the DC output terminal P and the DC output terminal N side, the first differential operation unit switching unit 19 and the second differential operation unit switching unit 20 are switched to the reference unit 3 side. In the state, the reference voltage sources 21 and 2
2 is supplied to the differential operation unit 2B via the substitution detection unit 3A of the reference unit, and the substitution detection unit 3A and the differential computation unit 2B of the reference unit 3 measure the reference voltage sources 21 and 22 and measure the measurement results. Is output.

The voltage of the voltage sensor circuit 2 is measured by measuring the input voltage of the voltage sensor circuit 2 or the potential of each section such as the input voltage and output voltage of the differential operation section 2B by the voltmeter 23 while performing such switching operations. 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 is operating normally.

Therefore, according to this embodiment, the first detector switching means 17 and the second detector switching means 18, the first differential operation section switching means 19 and the second differential operation section switching means 2 are provided.
By combining the switching with 0, the voltage sensor circuit 2
The operation check of each of the detection unit 2A and the differential operation unit 2B can be efficiently and reliably performed.

Embodiment 5 FIG. Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 7 is an electric circuit diagram illustrating the configuration of the voltage sensor circuit according to the fifth embodiment. 7, the same or corresponding parts as in FIG. 4 are denoted by the same reference numerals and description thereof is omitted, but the first detection unit switching unit 13 and the second detection unit switching unit 14 of the voltage sensor circuit of this embodiment are The configuration is the same as the first detection unit switching unit and the second detection unit switching unit used in the voltage sensor circuit of the second embodiment shown in FIG. 4 including the wiring relationship. Is the same as the conventional one.

In this embodiment, as in the second embodiment, the first detector switching means 13 and the second detector switching means 14 are connected to the positive power supply voltage output terminal 11 and the negative power supply voltage output terminal 11 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, and 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.

Embodiment 6 FIG. Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 8 is an electric circuit diagram illustrating the configuration of the voltage sensor circuit according to the sixth embodiment. 8, the same or corresponding parts as those in FIG. 5 are denoted by the same reference numerals and description thereof will be omitted. However, the first detection unit switching unit 13 and the second detection unit switching unit 14 of the voltage sensor circuit of this embodiment, First
The differential operation unit switching unit 15 and the second differential operation unit switching unit 16 include the first detection unit switching unit used in the voltage sensor circuit of the third embodiment shown in FIG.
It has the same configuration as the detection unit switching unit, the first differential operation unit switching unit, and the second differential operation unit switching unit, and the configuration of the voltage sensor circuit is the same as that of the related art.

In this embodiment, as in the third embodiment, the first differential operation unit switching means 15 and the second differential operation unit switching means 16 are connected to the positive power supply voltage output terminal 11 of the differential operation unit 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. The function check of the detection unit 2A and the differential operation unit 2B of the voltage sensor circuit 2 can be performed with a simpler circuit configuration having a smaller number of components than that of the first embodiment.

Embodiment 7 FIG. Hereinafter, a seventh embodiment of the present invention will be described with reference to the drawings. FIG. 9 is an electric circuit diagram illustrating the configuration of the voltage sensor circuit according to the present embodiment. In FIG. 9, the same or corresponding parts as those in FIG. 6 are denoted by the same reference numerals, and description thereof will be omitted. However, the first detection unit switching unit 17 and the second detection unit switching unit 18 of the voltage sensor circuit of this embodiment, The first differential operation unit switching unit 19, the second differential operation unit switching unit 20, and the reference unit 3 are connected to each other in FIG.
The first detection unit switching unit, the second detection unit switching unit, the first differential operation unit switching unit, the second differential operation unit switching unit, and the reference unit used in the voltage sensor circuit of the fourth embodiment shown in FIG. The configuration is the same, and the configuration of the voltage sensor circuit is the same as the conventional one.

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

In this embodiment, in particular, when there is a demand that the conventional voltage sensor circuit shown in FIG. 10 be continuously used, the change of the circuit configuration is minimized, and the function check is easily performed. Or when it is difficult to additionally mount the third resistance element RY.

[0063]

As described above, according to the first aspect of the present invention, the first resistance element in which the detection unit of the voltage sensor circuit is connected to one of the DC voltage output terminals to be measured, and the first resistance element A second resistance element connected to the other of the measured DC voltage output terminals having the same resistance value as the resistance value, and a serial connection between the first resistance element and the second resistance element on the differential operation unit side. And a third resistance element connected thereto, and the differential operation unit is configured to perform a differential operation on outputs at both ends of the third resistance element. This has the effect of obtaining a voltage sensor circuit capable of suppressing the occurrence of a voltage.

According to the second aspect of the 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 connected on the differential operation unit side. The resistance value of the third resistance element connected in series between the first and second resistance elements, and the resistance values of the first resistance element and the second resistance element are set in a range from about 100 kΩ or more to several hundred kΩ or less. With such a configuration, the rate of change of the resistance values 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 can be obtained.

According to the third aspect of the present invention, the detection unit switches the connection of the detection unit to one of the DC voltage output terminal for outputting the DC voltage to be measured and the reference voltage source for generating the reference voltage. Since the configuration is such that the unit switching means is provided, 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 properly can be obtained.

According to the fourth aspect of the present invention, when the measured DC voltage output terminal side to which the measured DC voltage is output or the power supply voltage of the power supply for operating the differential operation unit is used as the reference voltage source. Select either one of this reference voltage source side,
Since the detection unit switching means for switching the connection of the detection unit is provided, whether the detection unit and the differential operation unit are functioning normally based on the power supply voltage of the power supply for operating the differential operation unit There is an effect that a voltage sensor circuit that can easily perform a test of whether or not the voltage sensor can be obtained.

According to the fifth aspect of the present invention, the differential operation unit switching means for selecting either the output at both ends of the third resistance element of the detection unit or the output of the reference voltage source and supplying it to the differential operation unit. By selecting the reference voltage source output by the differential operation unit switching unit or the detection unit switching unit, whether the detection unit or the differential operation unit is functioning properly is determined. There is an effect that a voltage sensor circuit that can easily perform an inspection is obtained.

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

According to the seventh aspect of the present invention, a voltage detecting means for detecting the potential level of each section with reference to the neutral point potential of the alternative reference voltage source for generating the reference voltage, and one of the alternative reference voltage sources And a fifth resistor connected to the other reference voltage output terminal of the alternative reference voltage source, and a fourth resistor connected to the differential operation unit. And a sixth resistance element connected in series between the fifth resistance element and a sixth resistance element, and a measured DC voltage output from a measured DC voltage output terminal is supplied to the alternative reference voltage source. And a switching unit for replacing the detection unit with the replacement detection unit. Therefore, the operation of each unit of the voltage sensor circuit can be performed normally using the replacement reference voltage source and the voltage detection unit. Easily determine whether or not Voltage sensor circuit is effective to obtain that.

According to the invention of claim 8, in the conventional voltage sensor circuit, the connection of the detecting section is switched and switched to either the DC voltage output terminal side to output the DC voltage to be measured or the reference voltage source side. Since the circuit configuration of the detection unit and the differential operation unit is the same as before, the difference when the connection of the detection unit is switched to the reference power supply side by the detection unit switching unit is configured. Based on the measurement result output from the dynamic operation 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 is obtained.

According to the ninth aspect of the present invention, the connection of the detection circuit is switched to one of a measured DC voltage output terminal from which a measured DC voltage is output and a power supply for operating a differential operation unit. Since the detection unit switching means is configured to be selected, the circuit configuration of the detection unit and the differential operation unit remains unchanged, and the connection of the detection unit is operated by the detection unit switching unit to operate the differential operation unit. Voltage sensor that can easily check whether the detection unit and the differential operation unit are functioning normally based on the measurement results output from the differential operation unit when switching to the power supply side There is an effect that a circuit can be obtained.

According to the tenth aspect of the present invention, a difference for selecting either the output of the detection unit including the first resistance element and the second resistance element or the output of the reference voltage source and supplying it to the differential operation unit. Since the dynamic calculation unit switching means is provided, the reference voltage source output is selected by the differential calculation unit switching unit or the detection unit switching unit while the circuit configuration of the detection unit and the differential calculation unit remains unchanged. Thus, it is possible to obtain a voltage sensor circuit that can easily inspect 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, a voltage detecting means for detecting a potential level of each section based on a neutral point potential of a substitute reference voltage source for generating a reference voltage, and one of the substitute reference voltage sources An alternative detection unit comprising: a fourth resistance element connected to the reference voltage output terminal of the first embodiment, and a 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. Is configured to replace the DC voltage to be measured output from the alternative reference voltage source with the switching unit for replacing the detection unit with the replacement detection unit, so that the circuit configuration of the detection unit and the differential operation unit Has the effect of obtaining a voltage sensor circuit that can easily determine whether or not each part of the voltage sensor circuit is operating normally using the alternative reference voltage source and the voltage detection means.

[Brief description of the drawings]

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

FIG. 2 is a numerical explanatory diagram illustrating 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 shows the 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; FIG. 5 is a numerical value explanatory diagram showing a ratio of an error to an output voltage value.

FIG. 4 is an electric circuit diagram showing a configuration of a voltage sensor circuit according to Embodiment 2 of the present invention.

FIG. 5 is an electric circuit diagram showing a configuration of a voltage sensor circuit according to Embodiment 3 of the present invention.

FIG. 6 is an electric circuit diagram showing a configuration of a voltage sensor circuit according to Embodiment 4 of the present invention.

FIG. 7 is an electric circuit diagram showing a configuration of a voltage sensor circuit according to Embodiment 5 of the present invention.

FIG. 8 is an electric circuit diagram showing a configuration of a voltage sensor circuit according to Embodiment 6 of the present invention.

FIG. 9 is an electric circuit diagram showing a configuration of a voltage sensor circuit according to Embodiment 7 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 value explanatory diagram numerically showing a state in which a potential and a current of each section change when a resistance RX changes in a conventional voltage sensor circuit.

[Explanation of symbols]

P, N DC output terminals (DC voltage output terminals to be measured), 2
Voltage sensor circuit, 2A detection unit, 2B differential operation unit,
RX1 resistance (first resistance element), RX2 resistance (second resistance element)
, RY 3rd resistance element, 13 1st detector switching means (detector switching means), 14 2nd detector switching means (detector switching means), 15 1st differential operation section switching means ( Differential operation unit switching unit), 16 second differential operation unit switching unit (differential operation unit switching unit), 17 first detection unit switching unit (switching unit), 18 second detection unit switching unit (switching unit), 19 First differential operation unit switching means (switching means), 2
0 Second differential operation unit switching means (switching means), 21, 22
Reference voltage source (alternate reference voltage source), 23 voltmeter (voltage detection means), RX01 resistor (fourth resistance element), RX0
2 resistance (fifth resistance element), RY0 resistance (sixth resistance element), 3A alternative detection unit.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-165598 (JP, A) JP-A-2-45768 (JP, A) JP-A-56-51609 (JP, A) JP-A-60-1985 22746 (JP, A) JP-A-4-351969 (JP, A) JP-A-59-160317 (JP, A) JP-A-5-322937 (JP, A) JP-A-6-289058 (JP, A) JP-A-4-138378 (JP, A) JP-A-63-113967 (JP, A) JP-A-59-175181 (JP, U) JP-A-60-113560 (JP, U) JP-B-58-280 (JP, B2) JP-B-51-29429 (JP, B1) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01R 19/00-19/32 G01R 35/00-35/06 G05F 1 / 10 H02M 7/48-7/5395

Claims (11)

(57) [Claims] An output of a detection unit connected to a DC voltage output terminal to which a DC voltage to be measured is applied is subjected to a differential operation in a differential operation unit, and a voltage output value as a result of the differential operation is calculated. A voltage sensor circuit for measuring a measured DC voltage output from the measured DC voltage output terminal, wherein a first resistance element connected to one of the measured DC voltage output terminals and the other of the measured DC voltage A second resistance element connected to an output terminal and having a resistance equal to the first resistance element;
The differential operation unit comprises the detection unit including a third resistance element connected in series between the first resistance element and the second resistance element. A voltage sensor circuit that performs a differential operation on outputs at both ends of a third resistance element. 2. The resistance value of the first resistance element and the resistance value of 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 adjusted. 2. The voltage sensor circuit according to claim 1, wherein the resistance value is set in a range from about 100 kΩ or more to several hundred kΩ or less. 3. A detection for selecting either to connect the detection unit to a DC voltage output terminal to which the DC voltage to be measured is output or to connect to a reference voltage source for generating a reference voltage. 3. The voltage sensor circuit according to claim 1, further comprising a unit switching unit. 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 unit switching means for selecting either an output at both ends of the third resistance element or a reference voltage source output for generating the reference voltage and supplying the output to the differential operation unit. 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 unit. 7. A differential operation unit performs a differential operation on an output of a detection unit connected to a measured DC voltage output terminal from which a measured DC voltage is output, and based on the voltage output value as a result of the differential operation. 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 each of the components based on the neutral point potential of the alternative reference voltage source Voltage detecting means for detecting a potential level, a fourth resistance element connected to one of the reference voltage output terminals 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 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 unit side; The voltage output from the DC voltage output terminal The measured DC voltage is replaced with a reference voltage output from the alternative reference voltage source, and the detection unit is replaced with the alternative detection unit, or the measured DC voltage output from the measured DC voltage output terminal is replaced with the alternative reference voltage. Switching means for substituting a reference voltage output from a voltage source, wherein the differential operation section performs differential operation on the output at both ends of the third resistance element or the output at both ends of the sixth resistance element. A voltage sensor circuit characterized by the above-mentioned. 8. A first resistive element connected to a measured DC voltage output terminal from which a measured DC voltage is output, 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 composed of the second resistance element connected to the terminal is subjected to a differential operation in the differential operation unit, and is output from the DC voltage output terminal to be measured based on the voltage output value that is the result of the differential operation. In the voltage sensor circuit that measures the measured DC voltage, whether the detection unit is connected to a measured DC voltage output terminal from which the measured DC voltage is output or to a reference voltage source that generates a reference voltage And a detecting unit switching means for selecting either one of the voltage sensor circuits. 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 unit. 10. A differential operation for selecting one of an output of a detection unit including the first resistance element and the second resistance element and an output of the reference voltage source and supplying the output to the differential operation unit. The voltage sensor circuit according to claim 8, further comprising a unit switching unit. 11. A first resistive element connected to a measured DC voltage output terminal from which a measured DC voltage is output, and connected to one of the measured DC voltage output terminals and the other of the measured DC voltage output. An output of the detection unit including the second resistance element connected to the terminal is subjected to a differential operation in a differential operation unit, and an output is output from the DC voltage output terminal to be measured based on a voltage output value as a result of the differential operation A reference voltage source for generating a reference voltage, and voltage detecting means for detecting a potential level of each part with reference to a neutral point potential of the alternative reference voltage source. When,
An alternative detection unit comprising 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; Replacing the measured DC voltage output from the measured DC voltage output terminal with the alternative reference voltage source and replacing the detecting unit with the alternative detecting unit, or outputting the measured DC voltage from the measured DC voltage output terminal. A voltage sensor circuit comprising switching means for replacing a measured DC voltage with a reference voltage output from the alternative reference voltage source.