Measurement system

Abstract

This measurement system is provided with: a voltage conversion circuit that converts and outputs a voltage between a first terminal and a second terminal; and an arithmetic device that detects an abnormality in the voltage conversion circuit, the voltage conversion circuit including: a first output circuit that outputs a first voltage signal obtained by multiplying a potential of the first terminal with respect to a predetermined reference potential by a conversion gain; a second output circuit that outputs a second voltage signal obtained by multiplying the potential of the second terminal with respect to the reference potential by the conversion gain; and a third output circuit that outputs a third voltage signal obtained by multiplying a voltage between the first terminal and the second terminal by a conversion gain, and the conversion gain of the first output circuit, the second output circuit, and the third output circuit can be set with at least a first group and a second group of values. The ratio of the conversion gain of the first group to the conversion gain of the second group, which is set for the third output circuit, is different from the ratio of the conversion gain of the first group to the conversion gain of the second group, which is set for the first output circuit or the second output circuit. The voltage sensor is used for measuring a first voltage signal, a second voltage signal and a third voltage signal; and a diagnostic unit that calculates, from the first voltage signal, the second voltage signal, and the third voltage signal, a first conversion value, a second conversion value, and a third conversion value corresponding to the input voltage to the first output circuit, the second output circuit, and the third output circuit, using a conversion gain of a selected group, which is one of the first group and the second group. When the sum of the first conversion value and the second conversion value deviates from the third conversion value by a predetermined value or more, it is determined that there is an abnormality.

Description

Technical Field

[0001] This invention relates to a measuring system. Background Technology

[0002] A structure is known for measuring high voltages by reducing the voltage with a predetermined gain. A method is known for switching the gain according to the object being measured when there are multiple voltage ranges for the object being measured. Patent Document 1 discloses a voltage detection device comprising: a first resistive element for dividing the voltage of a detection unit into a first voltage division value; and a test mode insertion circuit comprising a second resistive element for dividing the first voltage division value into a second voltage division value and a switching element, the test mode insertion circuit being connected to a connection point at the same potential as the first voltage division value, and detecting the state of the first resistive element based on the second voltage division value when the switching element is not conducting.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-112526 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] In the invention described in Patent Document 1, there is room for improvement in reliability.

[0008] Methods for solving problems

[0009] The measurement system of the first aspect of the present invention includes: a voltage conversion circuit that converts and outputs a voltage between a first terminal and a second terminal; and a computing device that detects an anomaly in the voltage conversion circuit, wherein the voltage conversion circuit includes: a first output circuit that outputs a first output voltage obtained by multiplying the potential of the first terminal relative to a predetermined reference potential by a conversion gain; a second output circuit that outputs a second output voltage obtained by multiplying the potential of the second terminal relative to the reference potential by a conversion gain; and a third output circuit that outputs a third output voltage obtained by multiplying the voltage between the first terminal and the second terminal by a conversion gain, wherein the conversion gains of the first output circuit, the second output circuit, and the third output circuit can be set to at least a first set and a second set of values, and the third output circuit is configured... The ratio of the conversion gain of the first group to the conversion gain of the second group is different from the ratio of the conversion gain of the first group to the conversion gain of the second group set for the first output circuit or the second output circuit. The arithmetic device includes: a voltmeter that measures the first output voltage, the second output voltage, and the third output voltage; and a diagnostic unit that uses the conversion gain of a selected group, which is one of the first group and the second group, to calculate a first conversion value, a second conversion value, and a third conversion value corresponding to the input voltage to the first output circuit, the second output circuit, and the third output circuit based on the first output voltage, the second output voltage, and the third output voltage, and determines an abnormality if the sum of the first conversion value and the second conversion value deviates from the third conversion value by more than a predetermined value.

[0010] Invention Effects

[0011] According to the present invention, gain switching faults can be detected without limitation of conditions, thereby improving reliability. Attached Figure Description

[0012] Figure 1 This is a structural diagram of the measurement system.

[0013] Figure 2 This is a hardware structure diagram of the computing device.

[0014] Figure 3 This is a flowchart illustrating the processes handled by the diagnostic department.

[0015] Figure 4 This is a diagram showing the output of each group in the configuration example.

[0016] Figure 5 This is a diagram showing the connection of the output circuit in Variation Example 3.

[0017] Figure 6 It means and Figure 5The corresponding output graphs for each group.

[0018] Figure 7 This is a diagram illustrating a calculation example in the second embodiment. Detailed Implementation

[0019] First Implementation Method

[0020] The following is for reference Figures 1-4 This describes the first embodiment of the measurement system.

[0021] (structure)

[0022] Figure 1 This is a structural diagram of the measurement system 1. The measurement system 1 includes a voltage conversion circuit 100 and a processing unit 200. An HV voltage 101V is applied from an HV power supply 101 to the voltage conversion circuit 100. The HV voltage 101V is, for example, a high voltage such as 800V, which is difficult to measure directly. Therefore, the voltage conversion circuit 100 converts the HV voltage 101V into a low voltage, and a voltmeter built into the processing unit 200 measures this low voltage. In order to measure the voltage with high accuracy, the processing unit 200 preferably converges to a relatively large value within the measurable range.

[0023] Furthermore, the voltage conversion circuit 100 and the arithmetic unit 200 do not always use the same HV power supply 101 as the measurement object. Therefore, by switching the gain (described later) of the voltage conversion circuit 100 in correspondence with the measurement object HV power supply 101, the arithmetic unit 200 can measure the voltage with high accuracy. The arithmetic unit 200 can calculate the voltage of the HV power supply 101 using the measured voltage and the gain value used by the voltage conversion circuit 100 in the measurement.

[0024] The voltage conversion circuit 100 includes a first output circuit 11, a second output circuit 12, a third output circuit 13, a gain adjustment unit 102, a standard indication unit 110, a correction indication unit 114, a difference compensation circuit 115, and first voltage divider resistors R1 to fourth voltage divider resistors R4. The input voltage to the first output circuit 11 is called the first input voltage VI1, and the output voltage of the first output circuit 11 is called the first output voltage VO1. The input voltage to the second output circuit 12 is called the second input voltage VI2, and the output voltage of the second output circuit 12 is called the second output voltage VO2. The input voltage to the third output circuit 13 is called the third input voltage VI3, and the output voltage of the third output circuit 13 is called the third output voltage VO3. The third input voltage VI3 is equal to the sum of the first input voltage VI1 and the second input voltage VI2.

[0025] The first voltage divider resistors R1 through R4 divide the 101V power supply voltage. In this embodiment, for ease of explanation, the first voltage divider resistors R1 through R4 are set to the same value. However, the first voltage divider resistors R1 through R4 can also have different values. The second voltage divider resistor R2 and the third voltage divider resistor R3 are connected to ground potential. When the power supply voltage 101V is 1000V, the first input voltage VI1 is +250V, the second input voltage VI2 is -250V, and the third input voltage VI3 is +500V.

[0026] The positive side of the fourth voltage divider resistor R4 is referred to as the first potential point P1. The area between the fourth voltage divider resistor R4 and the third voltage divider resistor R3 is referred to as the second potential point P2. The area between the third voltage divider resistor R3 and the second voltage divider resistor R2 is referred to as the third potential point P3. The area between the second voltage divider resistor R2 and the first voltage divider resistor R1 is referred to as the fourth potential point P4. The negative side of the first voltage divider resistor R1 is referred to as the fifth potential point P5. Hereinafter, the second potential point P2 will also be referred to as the "first terminal", and the fourth potential point P4 will also be referred to as the "second terminal".

[0027] The first output circuit 11, the second output circuit 12, and the third output circuit 13 are each set to one of two gains via the gain changing unit 102. The gains can be different, but the gain switching is at the same timing. Hereinafter, the two gains set will be referred to as "Group A" and "Group B". Furthermore, the group set in the voltage conversion circuit 100 within "Group A" and "Group B" will be referred to as the "circuit utilization group", and the group that the arithmetic device 200 identifies as being utilized will be referred to as the "device identification group". Additionally, for ease of drawing, in... Figure 1 Detailed descriptions are omitted, but the first output circuit 11 and the second output circuit 12 are differential amplifier circuits.

[0028] The gain of group A or the gain of group B is simultaneously set for the first output circuit 11, the second output circuit 12, and the third output circuit 13. For example, we do not consider a situation where the gain of group A is set for the first output circuit 11, and the gain of group B is set for the second output circuit 12 and the third output circuit 13. The gains of group A for the first output circuit 11, the second output circuit 12, and the third output circuit 13 are, for example, "0.1, 0.1, 0.3", and the gains of group B are, for example, "0.02, 0.02, 0.4". In this case, group A is applied when the gain of the first output circuit 11 is set to "0.1", therefore the gain of the second output circuit 12 is set to "0.1", and the gain of the third output circuit 13 is set to "0.3".

[0029] When the gain adjustment unit 102 receives a change command from the standard indication unit 110 or the correction indication unit 114, it switches the gain of the first output circuit 11, the second output circuit 12, and the third output circuit 13. The standard indication unit 110 is an indication unit operated manually by the operator or by a setting device (not shown). The correction indication unit 114 is an indication unit operated by the arithmetic unit 200.

[0030] The standard indicator 110 and the correction indicator 114 operate from different entities, but their effects on the gain change unit 102 are the same regardless of which is operated. The difference compensation circuit 115 is a circuit that compensates for the difference between the standard indicator 110 and the correction indicator 114. Figure 1 In this configuration, both the standard indicator 110 and the correction indicator 114 are connected to the difference compensation circuit 115, and are connected to the gain change unit 102 via the difference compensation circuit 115. However, it is also possible for only one of the standard indicator 110 and the correction indicator 114 to be connected to the difference compensation circuit 115.

[0031] The hardware structures of the standard indicator 110 and the correction indicator 114 can be the same or different. For example, the standard indicator 110 is a push-button switch, which, when pressed, applies a predetermined voltage from a pre-prepared voltage source to the gain conversion unit 102. The correction indicator 114 is a contact that applies an electrical signal from the arithmetic unit 200, which can also apply a predetermined voltage if it determines that gain correction is needed. The difference compensation circuit 115 can be either an analog circuit or a digital circuit, or a combination of both. Furthermore, if the outputs of the standard indicator 110 and the correction indicator 114 are the same, the voltage conversion circuit 100 may not need to include the difference compensation circuit 115.

[0032] The arithmetic unit 200 includes a voltage measuring unit 210 and a diagnostic unit 220. The voltage measuring unit 210 is a voltmeter with a fixed measuring range, measuring a first output voltage VO1, a second output voltage VO2, and a third output voltage VO3, and outputting the measurement results to the diagnostic unit 220. The voltage measuring unit 210 uses ground potential as the reference for voltage measurement. The voltage measuring unit 210 can have three built-in voltmeters, or it can have one built-in voltmeter and a switching circuit. The voltage measuring unit 210 outputs the measured value directly to the diagnostic unit 220, without outputting the calculated result using gain. The voltage measuring unit 210 also uses the gain of the group recognized by the arithmetic unit 200, i.e., the device recognition group, to calculate the HV voltage 101V, and outputs it to the outside of the arithmetic unit 200.

[0033] The diagnostic unit 220 uses the voltage values ​​measured by the voltage measuring unit 210 to calculate the first input voltage VI1, the second input voltage VI2, the third input voltage VI3, and the HV voltage 101V. The diagnostic unit 220 also detects unwanted gain switching; in other words, it detects inconsistencies between the detection device identification group and the circuit utilization group. When an unwanted gain switching is detected, the diagnostic unit 220 outputs a gain switching indication to the correction indication unit 114 of the voltage conversion circuit 100.

[0034] The gain of each output circuit is changed by the gain changing unit 102 based on the input to the standard indicator 110 or the correction indicator 114, but sometimes it may change unexpectedly due to circuit malfunctions. The arithmetic unit 200 knows in advance the gain values ​​of groups A and B, as well as the information on the circuit utilization group. The arithmetic unit 200 does not obtain the value of the HV voltage 101V in advance, so it cannot detect undesirable changes in gain based on the measured value itself. The arithmetic unit 200 detects changes in gain using the correlation of the measured values, as detailed later.

[0035] The diagnostic unit 220 of the arithmetic unit 200 calculates the deviation DF using the following equations 1 to 4. G1 to G3 in equations 1 to 3 are the gains of the first output circuit 11, the second output circuit 12, and the third output circuit 13. In equations 1 to 3, the arithmetic unit 200 uses the gain values ​​of the device identification groups in groups A and B. Note that VO1 and VO2 in equations 1 and 2 below are not the measured first output voltage VO1 and second output voltage VO2 themselves, but rather the values ​​after removing the bias value.

[0036]

[0037] The diagnostic unit 220 determines that the deviation DF is normal if it is less than a predetermined threshold, and abnormal if the deviation DF is greater than or equal to the predetermined threshold. When the voltage conversion circuit 100 and the diagnostic unit 220 use the same gain value, the deviation DF is approximately zero. However, when the voltage conversion circuit 100 and the arithmetic unit 200 use different gain values—in other words, when the voltage conversion circuit 100 uses a gain value that is not in the device identification group—the deviation DF becomes a non-zero value. When the deviation DF is greater than or equal to the predetermined threshold, the diagnostic unit 220 instructs the correction indication unit 114 of the voltage conversion circuit 100 to change the gain.

[0038] Figure 2This is a hardware structure diagram of the arithmetic unit 200. The arithmetic unit 200 includes a CPU 41 as a central processing unit, a ROM 42 as a dedicated read / write storage device, a RAM 43 as a read / write storage device, a voltmeter 44, and a signal output unit 45. The arithmetic unit 200 is a microcomputer, a single-board computer, or an electronic control device, etc. The CPU 41 implements the diagnostic unit 220 by expanding and executing a program stored in the ROM 42 in the RAM 43. The voltmeter 44 is capable of measuring at least one measurement range, for example, 0~5V. The signal output unit 45 is hardware used to output action commands to the correction instruction unit 114. The signal output unit 45 only needs to be able to output a signal corresponding to the hardware structure of the correction instruction unit 114, for example, it only needs to be able to output a predetermined voltage signal or a predetermined voltage signal.

[0039] The arithmetic unit 200 can also replace the combination of CPU 41, ROM 42, and RAM 43 by having an FPGA (Field Programmable Gate Array) as a rewritable logic circuit or an ASIC (Application Specific Integrated Circuit) as an application-specific integrated circuit. Alternatively, the arithmetic unit 200 can replace the combination of CPU, ROM, and RAM by using combinations of different structures, such as a combination of CPU, ROM, RAM, and FPGA.

[0040] (Actions of the diagnostic department)

[0041] Figure 3 This is a flowchart illustrating the processing of the diagnostic unit 220. The diagnostic unit 220 performs operations at predetermined intervals, such as every minute or every hour. Figure 2 The processing shown is as follows. The computing device 200 uses the gain of the device identification group to perform the processing of this flowchart.

[0042] In step S301, the diagnostic unit 220 first calculates the deviation DF using the output of the voltage measuring unit 210. In the next step S302, the diagnostic unit 220 determines whether the deviation DF calculated in step S301 is less than a threshold. If the diagnostic unit 220 determines that the deviation DF is less than the threshold, it determines that there is no abnormality, i.e., the circuit utilization group and the device identification group are the same, and the process ends. Figure 2 The process is as shown. If the deviation DF is above the threshold, the diagnostic unit 220 determines it to be abnormal and proceeds to step S303.

[0043] In step S303, the diagnostic unit 220 instructs the correction instruction unit 114 to change the gain. This instruction, for example, applies a predetermined voltage to the correction instruction unit 114. In the next step S304, the diagnostic unit 220 recalculates the deviation DF using the output of the voltage measurement unit 210 after step S303. The purpose of this recalculation is to confirm that the gain used by the voltage conversion circuit 100 has been changed according to the correction instruction in step S303. Therefore, a predetermined standby time, such as several seconds, can be allowed after step S303 is executed.

[0044] In the next step S305, the diagnostic unit 220 determines whether the deviation DF calculated in step S304 is less than a threshold. If the diagnostic unit 220 determines that the deviation DF is less than the threshold, it determines that the correction indication in step S303 is functioning normally, the problem has been eliminated, and the process ends. Figure 2 The process is as shown. If the diagnostic unit 220 determines that the deviation DF is above the threshold, it proceeds to step S306. In step S306, even if the diagnostic unit 220 sends a correction instruction to the voltage conversion circuit 100, it does not perform a correction; therefore, as a suboptimal countermeasure, it changes the device identification group to the other party and ends the process. Figure 2 The processing shown.

[0045] (Example setting)

[0046] Gain is typically determined by the ratio of the maximum value that the voltmeter can measure to the maximum voltage value output by the object being measured. When considering changes to the object being measured, the maximum value that the voltmeter can measure is usually kept constant, while the maximum voltage value output by the object being measured is varied to determine different gains. In this embodiment, the maximum value that the voltmeter can measure is intentionally changed to set the gain. The purpose of this change is to determine the gain group. In the setting example described below, the maximum voltage value in the third output circuit 13 is changed for each group.

[0047] The following describes examples of gain setting and calculation for the HV voltage 101V of the measured object being 800V and 1200V. In this example, the gain corresponding to 800V is designated as group A, and the gain corresponding to 1200V is designated as group B. The maximum voltage of the third output voltage VO3 is set to 4.5V at 1200V and 4.8V at 800V. These values ​​are, for example, set to 4.8V with a 0.2V margin above the upper limit of the voltmeter built into the voltage measuring unit 210 (5.0V), and further reduced to 4.5V by 0.3V for the purpose of group discrimination.

[0048] The third input voltage VI3 becomes 400V when the HV voltage is 101V (800V) through a voltage divider resistor, and becomes 600V when the HV voltage is 101V (1200V). Therefore, the gain of the third output circuit 13 is 4.5V / 400V = 0.01125 in group A and 4.8V / 600V = 0.008 in group B. The first input voltage VI1 and the second input voltage VI2 are differential amplifier circuits with a bias voltage of 2.5V, and the measurement range is divided into 200V and 300V respectively. That is, the gain in group A is 2.0V / 200V = 0.01, and the gain in group B is 2.0V / 300V = 0.0067.

[0049] Figure 4 This diagram illustrates the outputs of each group in the given configuration example. In this diagram, the first output voltage VO1 is represented by a straight line, the second output voltage VO2 by a dashed line, and the third output voltage VO3 by a dotted line. In group A, the maximum value of the HV voltage (101V) is 800V. At this time, the first output voltage VO1 to the third output voltage VO3 are 4.8V, 0.5V, and 4.8V, respectively. In group B, the maximum value of the HV voltage (101V) is 1200V. At this time, the first output voltage VO1 to the third output voltage VO3 are 4.5V, 0.5V, and 4.8V, respectively. Furthermore, in... Figure 4 The maximum value of each input voltage, i.e. the value at the right end of the graph, is shown in parentheses at the bottom of each graph.

[0050] The ratio of the gain of group A to the gain of group G set for the third output circuit 13, i.e., the third circuit gain ratio GR3, and the ratio of the gain of group A to the gain of group G set for the first output circuit 11, i.e., the first circuit gain ratio GR1, are as follows. Furthermore, the ratio of the gain of group A to the gain of group G set for the second output circuit 12, i.e., the second circuit gain ratio GR2, is the same as the first circuit gain ratio GR1.

[0051]

[0052] The ratio of the third circuit gain ratio GR3 to the first circuit gain ratio GR1 is approximately 0.942, therefore the difference is approximately 5.8%. If the voltage measurement accuracy in the voltage measurement unit 210 is 2%, it is preferable to add a 0.5% margin to twice 4%, resulting in a difference of 4.5%. In this example, the ratio of the third circuit gain ratio GR3 to the first circuit gain ratio GR1 satisfies the benchmark that the ratio difference is 4.5% or more.

[0053] With the HV voltage in group A being 101V and 400V (half of the maximum value in group A), the absolute values ​​of the first input voltage VI1 and the second input voltage VI2 are 100V through the voltage divider resistors, and the third input voltage VI3 is 200V. Therefore, the output is as follows: The first output voltage VO1 is 2.5 + 100V. 0.01 = 3.5V. The second output voltage VO2 is 2.5-100. 0.01 = 1.5V. The third output voltage VO3 is 200. 0.01125 = 2.25V. In this case, the arithmetic unit 200 calculates the deviation DF as follows when the group is identified as group A.

[0054] HVP is calculated as 100V by dividing 1V (excluding the bias voltage of 2.5V) by G1 (0.01). HVN is also calculated as 100V. HVC is calculated as 200V by dividing 2.25V by 0.01125 (G3). Therefore, the diagnostic unit 220 calculates the deviation DF as zero using 100 + 100 - 200.

[0055] However, assuming the identification is group B, the arithmetic unit 200 calculates the deviation DF as follows: HVP divides 1V by 0.0067 (G1) to calculate 149.25V. HVN also calculates 149.25V. HVC divides 2.25V by 0.008 (G3) to calculate 281.25V. Therefore, the deviation DF is 149.25 + 149.25 - 281.25 = 17.25, which is non-zero. Therefore, the diagnostic unit 220 can detect gain switching faults, in other words, the difference between the circuit utilization group and the device identification group, by using appropriate thresholds, such as "5" or "10".

[0056] According to the first embodiment described above, the following effects can be obtained.

[0057] (1) The measurement system 1 includes: a voltage conversion circuit 100 that converts and outputs the voltage between a first terminal and a second terminal; and an arithmetic unit 200 that detects abnormalities in the voltage conversion circuit 100. The voltage conversion circuit 100 has: a first output circuit 11 that outputs a first output voltage VO1 obtained by multiplying the potential of a second potential point P2, which is a first terminal relative to a predetermined reference potential, by a conversion gain; a second output circuit 12 that outputs a second output voltage VO2 obtained by multiplying the potential of a fourth potential point P4, which is a second terminal relative to a reference potential, by a conversion gain; and a third output circuit 13 that outputs a third output voltage VO3 obtained by multiplying the voltage between the second potential point P2 and the fourth potential point P4 by a conversion gain. The conversion gains of the first output circuit 11, the second output circuit 12, and the third output circuit 13 can be set to at least values ​​of group A and group B. The ratio of the conversion gain of group A to the conversion gain of group B set for the third output circuit 13, i.e., the third circuit gain ratio GR3, is different from the ratio of the conversion gain of group A to the conversion gain of group B set for the first output circuit 11, i.e., the first circuit gain ratio GR1. The arithmetic unit 200 includes: a voltage measuring unit 210 comprising a voltmeter for measuring a first output voltage VO1, a second output voltage VO2, and a third output voltage VO3; and a diagnostic unit 220 which uses a switching gain of group A or group B to calculate a first input voltage VI1, a second input voltage VI2, and a third input voltage VI3 based on the first output voltage VO1, the second output voltage VO2, and the third output voltage VO3. If the sum of the first input voltage VI1 and the second input voltage VI2 differs from the third input voltage VI3 by a predetermined value or more, an abnormality is determined. Therefore, gain switching faults can be detected regardless of the specific condition, improving reliability.

[0058] (2) When the arithmetic unit 200 determines that the diagnostic unit 220 is abnormal ( Figure 3 If (S302: No), a correction instruction is sent to the correction instruction unit 114 (S303), thereby changing the conversion gain of the first output circuit 11, the second output circuit 12, and the third output circuit 13 to the conversion gain of other groups. Therefore, the gain of the voltage conversion circuit 100, which may change due to adverse conditions, can be changed.

[0059] (3) When the diagnostic unit 220 determines that the arithmetic unit 200 is abnormal after changing the conversion gain of the first output circuit 11, the second output circuit 12, and the third output circuit 13 to the conversion gain of the selection group, Figure 3(S305: No), the arithmetic unit 200 uses a conversion gain (S306) that is different from the current identification group to calculate the first input voltage VI1, the second input voltage VI2, and the third input voltage VI3. Therefore, even if the gain setting in the voltage conversion circuit 100 cannot be corrected, the arithmetic unit 200 can continue to measure the HV voltage 101V by switching the gain used by the arithmetic unit 200.

[0060] (4) The ratio of the gain of group A to the gain of group G set for the third output circuit 13, i.e., the third circuit gain ratio GR3, and the ratio of the gain of group A to the gain of group G set for the first output circuit 11, i.e., the first circuit gain ratio GR1, are set to be a ratio that differs by more than 4.5%. Therefore, the arithmetic unit 200 can reliably detect gain switching faults in the voltage conversion circuit 100.

[0061] (Variation Example 1)

[0062] In the first embodiment described above, the voltage conversion circuit 100 includes four voltage divider resistors, namely, the first voltage divider resistor R1 to the fourth voltage divider resistor R4. However, the voltage conversion circuit 100 only needs to include at least two voltage divider resistors. That is, it can also be a structure that does not include the first voltage divider resistor R1 and the fourth voltage divider resistor R4, but only includes the second voltage divider resistor R2 and the third voltage divider resistor R3.

[0063] (Variation Example 2)

[0064] In the first embodiment described above, when an anomaly is detected, a correction instruction is first sent to the voltage conversion circuit 100. Figure 3 (S302: No, S303) Only if the subsequently calculated deviation DF is above the threshold will the unit change its own identification group (S306). However, the diagnostic unit 220 may also change its own identification group without sending a correction instruction. In this case, Figure 3 If a negative judgment is made in step S302, proceed to step S306.

[0065] According to this modified example, the following effects can be achieved.

[0066] (5) When the diagnostic unit 220 determines that there is an abnormality, the arithmetic unit 200 uses the conversion gain of the unidentified one of group A and group B to calculate the first input voltage VI1, the second input voltage VI2 and the third input voltage VI3.

[0067] (Variation Example 3)

[0068] In the first embodiment described above, the first output circuit 11 and the second output circuit 12 employ differential amplifier circuits. However, the first output circuit 11 and the second output circuit 12 may also not employ differential amplifier circuits. In this case, the same method as in the first embodiment described above can also be used.

[0069] Figure 5 This is a diagram showing the connection of the output circuit in this variation. Figure 6 It means and Figure 5 The corresponding output graphs for each group. However, Figure 6 and Figure 4 Similarly, group A corresponds to the case where the HV voltage is 101V and the value is 800V, while group B corresponds to the case where the HV voltage is 101V and the value is 1200V.

[0070] (Variation Example 4)

[0071] In the first embodiment described above, the output voltage range of the third output circuit 13 is made different in groups A and B, but the output voltage ranges of the first output circuit 11 and the second output circuit 12 can also be made different. Alternatively, all output voltage ranges from the first output circuit 11 to the third output circuit 13 can be made different. In short, as long as the ratio of the third circuit gain ratio GR3 to the first circuit gain ratio GR1 differs by more than 4.5%, it is acceptable.

[0072] (Variation Example 5)

[0073] In the first embodiment described above, the voltage conversion circuit 100 and the arithmetic unit 200 were described as having different structures. However, the voltage conversion circuit 100 and the arithmetic unit 200 can also be configured as a single unit. In this case, the voltage conversion circuit 100 and the arithmetic unit 200 can be collectively referred to as a "voltage measuring device".

[0074] Second Implementation Method

[0075] Reference Figure 7 This section describes a second embodiment of the measurement system. In the following description, the same reference numerals are used to denote the same components as in the first embodiment, and the main differences are explained. Points not specifically described are the same as in the first embodiment. The main difference in this embodiment compared to the first embodiment is that the number of gain groups is four.

[0076] The structure and processing of the voltage conversion circuit 100 in the second embodiment are the same as those in the first embodiment, except that the gain group that the gain change unit 102 can change is four groups, and that it does not have the first voltage divider resistor R1 and the fourth voltage divider resistor R4. The structure and processing of the arithmetic device 200 are the same as those in the first embodiment. Hereinafter, an example of gain setting will be described.

[0077] In order to identify the difference between the circuit utilization group and the device identification group in the arithmetic unit 200 and to handle multiple HV voltage ranges of 101V, the maximum output voltage of the third output circuit 13 can be set to multiple values. If the voltage conversion circuit 100 and the diagnostic unit 220 use the same gain, the calculated deviation DF is approximately 0V. Furthermore, when the circuit utilization group and the device identification group are different, the deviation DF is non-zero, and the circuit utilization group can be determined based on the value of the deviation DF.

[0078] Here, as an example, the setting for the maximum measurement range of HV voltage 101V is explained when it is 400V, 600V, 800V, and 1200V. In this embodiment, the gain groups are named A, B, C, and D in order of the maximum measurement range. The maximum voltages of the third output circuit 13 are 4.00V, 4.19V, 4.39V, and 4.60V respectively. In this embodiment, the voltage conversion circuit 100 does not have the first voltage divider resistor R1 and the fourth voltage divider resistor R4, therefore the gains of the third output circuit 13 are 4.00V / 400V = 0.01, 4.19V / 600V = 0.006983, 4.39V / 800V = 0.005488, and 4.60V / 1200V = 0.003833 respectively.

[0079] The first output circuit 11 and the second output circuit 12 have a maximum fixed output voltage variation of 2.00V relative to the input voltages of 200V, 300V, 400V, and 600V. At this time, the gains of the PC voltage are 0.005, 0.003333, 0.0025, and 0.00166, respectively. Therefore, the gain ratios relative to the four gains are 0.01 / 0.005 = 2.000, 0.006983 / 0.003333 = 2.095, 0.005488 / 0.0025 = 2.195, and 0.003833 / 0.001667 = 2.300, respectively. These four gain ratios all differ from each other by more than 4.5%.

[0080] Figure 7 This is a diagram illustrating a calculation example in the second embodiment. Figure 7 This includes a voltmeter 801, a gain ratio table 802, and a deviation table 803. The voltmeter 801 displays the gain of each of the aforementioned groups and the values ​​used for gain calculation. Furthermore, the gain of the second output circuit 12 is the same as the gain of the first output circuit 11. The gain ratio table 802 displays the difference in gain ratios between each group. Specifically, the gain ratio table 802 displays the difference between the gain ratio of the group on the left side of the diagram and the ratio of the group at the top of the diagram, using the gain ratio of the group on the left side of the diagram as a reference. The gain ratio table 802 shows that all groups have a difference of 0.045, or 4.5%, or more.

[0081] Deviation Table 803 shows the deviation DF when an input of 300V is used. Specifically, the circuit utilization group is shown on the left side of the diagram, and the device identification group is shown at the top. The diagonally arranged zeros indicate that the deviation DF is zero when the circuit utilization group and the device identification group are the same. As shown in Deviation Table 803, it can be seen that when the circuit utilization group and the device identification group are inconsistent, the deviation DF is always a non-zero value. By using an appropriate threshold, such as "5", gain switching faults, in other words, differences between the circuit utilization group and the device identification group, can be detected.

[0082] In the above-described embodiments and variations, the structure of the functional blocks is merely one example. Several functional structures shown as different functional blocks can be integrally constructed, or the structure represented by a functional block diagram can be divided into two or more functions. Furthermore, other functional blocks can be configured to possess a portion of the functions of each functional block.

[0083] The various embodiments and modifications described above can also be combined. While various embodiments and modifications have been described above, the present invention is not limited to these. Other methods considered within the scope of the technical concept of the present invention are also included within the scope of the present invention.

[0084] Symbol Explanation

[0085] 1. Measurement system

[0086] 11 First output circuit

[0087] 13 Third output circuit

[0088] 100V conversion circuit

[0089] 101 HV power supply

[0090] 102 Gain Modification Unit

[0091] 110 Standard Instruction Department

[0092] 114 Correction Instructions Department

[0093] 115 difference compensation circuit

[0094] 200 computing devices

[0095] 210 Voltage Measurement Unit

[0096] 220 Diagnostic Department

[0097] DF deviation,

[0098] GR1 first circuit gain ratio,

[0099] GR3 third circuit gain ratio,

[0100] P2 second potential point

[0101] P4 fourth potential point

[0102] VI1 first input voltage,

[0103] VI3 third input voltage,

[0104] VO1 first output voltage,

[0105] VO3 is the third output voltage.

Claims

1. A measuring system, comprising: A voltage conversion circuit that converts and outputs the voltage between a first terminal and a second terminal; and a processing unit that detects abnormalities in the voltage conversion circuit, characterized in that... The voltage conversion circuit includes: The first output circuit outputs a first output voltage obtained by multiplying the potential of the first terminal relative to a predetermined reference potential by a conversion gain. A second output circuit outputs a second output voltage obtained by multiplying the potential of the second terminal relative to the reference potential by a conversion gain; and The third output circuit outputs a third output voltage obtained by multiplying the voltage between the first and second terminals by the conversion gain. The conversion gains of the first output circuit, the second output circuit, and the third output circuit can be set to at least the values ​​of the first and second groups. The ratio of the conversion gain of the first group to the conversion gain of the second group set for the third output circuit is different from the ratio of the conversion gain of the first group to the conversion gain of the second group set for either the first output circuit or the second output circuit. The computing device includes: A voltmeter that measures the first output voltage, the second output voltage, and the third output voltage; and The diagnostic unit uses the conversion gain of a selection group, which is one of the first group and the second group, to calculate a first conversion value, a second conversion value, and a third conversion value equivalent to the input voltages to the first output circuit, the second output circuit, and the third output circuit, based on the first output voltage, the second output voltage, and the third output voltage. If the sum of the first conversion value and the second conversion value deviates from the third conversion value by more than a predetermined value, it is determined to be abnormal.

2. The measuring system according to claim 1, characterized in that, If the diagnostic unit determines that an abnormality has occurred, the computing device uses the conversion gain of the first group and the group in the second group that is not the selected group to calculate the first conversion value, the second conversion value, and the third conversion value.

3. The measuring system according to claim 1, characterized in that, If the diagnostic unit determines that there is an abnormality, the arithmetic device changes the conversion gain of the first output circuit, the second output circuit, and the third output circuit to the conversion gain of the selection group.

4. The measuring system according to claim 3, characterized in that, When the diagnostic unit determines an abnormality after changing the conversion gain of the first output circuit, the second output circuit, and the third output circuit to the conversion gain of the selected group, the arithmetic device uses the conversion gain of the group that is not in the selected group from the first group and the second group to calculate the first conversion value, the second conversion value, and the third conversion value.

5. The measuring system according to claim 1, characterized in that, The ratio of the conversion gain of the first group to the conversion gain of the second group set for the third output circuit is set to a ratio that differs from the ratio of the conversion gain of the first group to the conversion gain of the second group set for the first output circuit or the second output circuit by more than 4.5%.

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