JP2007192615A - Abnormality detection method of voltage sensor, abnormality detection device, and the voltage sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an abnormality detection method of a monitoring measuring system in supply current monitoring that will not reduce measurement accuracy using a simple constitution, by solving the problems, wherein even though conventional methods for measuring both current and voltage are known for detecting an operation abnormalities of a monitoring device of the current supplied to a load from a direct-current power source, the number of components in a measuring system will increase and processing steps will also increase in the method by two-system measurement. <P>SOLUTION: This method has a constitution wherein a voltage applied to the load is detected, and a voltage sensor output is outputted by a differential voltage. An operation abnormality of the current monitoring device is detected, by detecting asymmetry of a differential output voltage generated by a defect of a circuit component or other wiring or the like in the voltage sensor. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an apparatus for detecting an abnormality of a voltage sensor that detects the voltage of a power source such as a battery for supplying power to an electric load, a detection method thereof, and a voltage sensor used for the apparatus.

Conventionally, as a device for determining an abnormal operation of a sensor that detects a charge / discharge current or voltage of a power source such as a battery for supplying power to an electric load, that is, a failure, a failure determination device described in Patent Document 1 below There is. This failure determination device has a configuration in which a voltage sensor and a current sensor are installed on the power supply line from the assembled battery to the load, and a temperature sensor is installed on the battery. Here, the voltage sensor calculates the supply current value from the measured voltage and compares it with the current sensor output, thereby detecting the abnormality of the current sensor. That is, a sensor failure detection is performed by comparing the outputs of two sensors.
JP-A-10-253682

  As described above, in the conventionally known current sensor failure determination device, a data processing circuit is provided for each of the plurality of sensors, and the failure determination is performed after the output of each data processing circuit is comprehensively processed. For this reason, the failure determination device reliability is lowered due to an increase in the number of components of the monitoring device. There is also a problem that the processing time becomes longer as the number of processing steps increases.

  For this reason, in the present invention, a failure determination device for a voltage sensor is realized without increasing the number of components of other sensors, thereby improving the reliability of failure determination and reducing the number of processing steps. The purpose of the present invention is to provide a failure determination device that can shorten the time required for failure determination processing.

  In order to achieve the above object, the present invention has the following configuration as a basic configuration. That is, the first and second voltages are generated in the differential output unit as a voltage difference of opposite phases according to the input voltage, and the intermediate value of these two voltages at the time of no input voltage, that is, the differential output unit This is a method for detecting the presence or absence of an abnormality in the differential output unit by detecting whether or not two output voltages having opposite phases from the differential output unit are symmetric with respect to the initial offset voltage.

  According to the present invention, the abnormality detection of the voltage sensor can be performed without providing other sensors, the number of parts of the device can be reduced, the reliability of failure detection is improved, and the processing steps required for failure detection The number can be reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows this basic configuration. The assembled battery 1 (battery) is connected to a load 3 via a main relay 2 constituting an electric main switch including an ignition switch. On the other hand, the output voltage of the assembled battery 1 is input to the differential output unit 6 via the switch 4 by dividing the voltage (input voltage) into a low voltage that can be input to the CPU 10 as the data processing unit by the voltage divider 5. The Here, the switch 4 is turned off when the CPU 10 is activated, and is used to check the initial offset of the differential voltage outputs V1 and V2 of the amplifier 9 immediately before the CPU 10 enters the operation state. Switch 4 is turned on when entering the operating state. The initial offset can be checked even when the chopper 7 is open.

  A signal (voltage) input to the differential output unit 6 is converted into an AC signal by the chopping (switching) operation of the chopper 7. Here, the voltage to be converted into the AC signal is remarkably different from that of the assembled battery 1 side and the signal processing circuit side after the differential output unit 6, and these two parts are electrically insulated to form AC coupling. This is necessary. In the circuit example of FIG. 1, transformer coupling is performed by a differential transformer 8. In order to achieve this transformer coupling, the chopper 7 converts the pulse signal into an AC signal. The oscillation circuit of this chopping frequency (pulse signal) is incorporated in the integrated circuit forming the amplifier 9.

  The secondary side of the differential transformer 8 has a grounded center tap, and outputs of opposite phases obtained from both ends of the secondary winding of the amplifier 9 constituting the differential input / differential output. Input to the input side. The amplifier 9 amplifies the inputted outputs having opposite phases, and outputs differential outputs V1 (first voltage) and V2 (second voltage) having opposite phases to the CPU 10. That is, the differential output unit 6 outputs differential voltages V1 and V2 having opposite phases to the A / D port 11 of the CPU 10 with a voltage difference corresponding to the voltage input from the voltage divider 5. The CPU 10 detects the voltage of the assembled battery 1 based on the voltage difference between the differential outputs V1 and V2 input from the A / D port 11, and is asymmetric with respect to the initial offset which is an intermediate value between the differential outputs V1 and V2 of the amplifier 9. Or a voltage detector for diagnosing an abnormality of the differential output unit 6 by performing an operation such as a shift in the intermediate value between the differential output voltages V1 and V2. That is, the voltage sensor 12 according to the present invention includes a differential output unit 6 and a CPU 10 including an A / D port 11 as shown in FIG. A method for detecting an operation abnormality of the differential output unit 6 in the battery operation monitoring apparatus having the above configuration by self-diagnosis will be described below.

(Embodiment 1)
FIG. 2 illustrates an abnormality detection process in the voltage sensor 12 that detects the output voltage of the power source such as the assembled battery 1 shown in FIG. When the apparatus of FIG. 1 is operating normally, the intermediate value of the differential outputs V1 and V2 of the amplifier 9 has the same value as an initial offset value Vmo described later in the amplifier 9, and the differential outputs V1 and V2 are The value is symmetrical with respect to this value. However, when, for example, the soldered portion of the winding portion of the differential transformer 8 is in a partially broken state due to corrosion or when the constants of the circuit components of the amplifier 9 change or the internal wiring of the integrated circuit causes a contact failure Etc., one or both of the differential outputs of the amplifier 9 change and become asymmetric. The processing procedure in the circuit example of FIG. 1 will be described below with reference to the flowchart of FIG.

If the differential output unit 6 is operating normally and the differential output of the differential output unit 6 when the chopper 7 is in the OFF state is V1o and V2o, respectively, the intermediate value becomes the initial offset value Vmo,
Vmo = (V1o + V2o) / 2 (Equation 1)
(Step S1). The intermediate value Vm between the differential outputs V1 and V2 of the differential output unit 6 when the chopper 7 is on is Vm = (V1 + V2) / 2 (Equation 2)
(Step S2). Here, the absolute value | ΔVm | of the difference voltage between the initial offset value Vmo and the intermediate value Vm of the differential outputs V1 and V2 is
| ΔVm | = | Vmo−Vm (normal) |
(Step S3). If the differential transformer 8 and the amplifier 9 are operating normally, the absolute value | ΔVm | should be zero. Here, when an abnormality occurs in the differential output unit 6 and one of the normal differential outputs V1 becomes V1 ′, the intermediate value Vm is shifted to the intermediate value Vm ′, and the absolute value ΔVm is 0. It takes no value.

| Vmo−Vm ′ (abnormality) |> abnormality determination value α (Equation 4)
When this value is larger than a predetermined first abnormality determination value α (step S4), it is determined that an abnormality has occurred (step S5).

  As described above, in the present invention, since it is possible to make an abnormality determination from a change in the intermediate value of the output voltage of the differential output unit 6, a conventional failure determination apparatus has a data processing circuit for each of a plurality of sensors. There is no need to provide a failure determination process by integrating data from multiple sensors, improving the reliability of the failure determination device, and at the same time suppressing an increase in processing steps. The increase in processing time could be suppressed.

  According to this method, since the absolute value | ΔVm | changes continuously from 0, not only when a complete failure occurs such as disconnection, short-circuiting, or sticking, but also the constants of circuit components change, for example. In this case, it is possible to detect a minor failure that can be a precursor to a future major failure such as a soldering failure of a differential transformer.

(Embodiment 2)
FIG. 4 shows an abnormality detection procedure for the second embodiment. The absolute values | ΔV1m ′ | and | ΔV2m | of the differences between the differential outputs V1 ′ (when abnormal) and V2 (when normal) with respect to the intermediate output Vmo giving the initial offset value in the first embodiment are obtained.

| ΔV1m ′ | = | V1′−Vmo | (Equation 5)
| ΔV2m | = | Vmo−V2 | (Equation 6)
Next, the difference between the equation (Equation 5) that gives the first voltage and the equation (Equation 6) that gives the second differential voltage is obtained, and the absolute value ΔVu that is the amount of asymmetry between V1 and V2 is given by ) Calculate from the formula.

| ΔVu | = | ΔV1m | − | ΔV2m | (Equation 7)
When this absolute value ΔVu is compared with a second abnormality determination value β set in advance and the condition of the following equation (8) is satisfied: | ΔVu |> abnormality determination value β (8)
Determines that an abnormality has occurred in the differential output unit 6.

  Even in the abnormality detection method in the voltage sensor according to the second embodiment, the abnormality determination can be performed only by detecting the differential output voltage with respect to the initial offset value, so that the reliability of the abnormality determination device can be improved and the number of steps can be reduced. Since the determination can be made, the processing time can be shortened.

(Embodiment 3)
FIG. 5 shows an abnormality detection procedure in the third embodiment of the present invention. In the third embodiment, the variation ΔV1 of the differential output voltages V1 and V2 of the differential output unit 6 with respect to a range (variation ΔVb) in which the input voltage in the battery side voltage of the assembled battery 1 is changed by a predetermined voltage. And ΔV2 are equal in the normal state. That is, in the normal state, | ΔV1 | = | ΔV2 |
However, for example, if an abnormality occurs on the V1 side and becomes V1 ′ shown in FIG. 5, this equality is not established, and the variation ΔV1 ′ in this case is | ΔV1 ′ | ≠ | ΔV2 | (Equation 10)
The absolute value | ΔVd | which is the difference between these two variations
| ΔVd | = || ΔV1 ′ | − | ΔV2 || (Equation 11)
Exceeds a preset third abnormality determination value γ, it is determined that an abnormality has occurred in the differential output unit 6. All operations for the processes described above are executed by the CPU 10.

  In each of the abnormality detection processes described above, the first to third abnormality determination values (either α, β, or γ) are set to the assembled battery 1 side voltage (V) or the power supply voltage of the differential output unit 6. It is also possible to adopt a configuration that changes in response to fluctuations. FIG. 6 shows an example of this situation, and shows a case where the abnormality determination value (vertical axis) and the battery side input voltage (horizontal axis) have a linear function relationship. In FIG. 6, the coefficient k giving the abnormality determination value is given by the product of the coefficient (k1) corresponding to the battery side voltage range input to the differential output unit 6 and the coefficient (k2) corresponding to the power supply voltage of the differential output unit 6. (K = k1 · k2), and the abnormality determination value (any one of α, β, and γ) is given by the product of the k value and the battery side voltage V (abnormality determination value = k · V). Show. By registering this relationship in the arithmetic system in the CPU 10 in advance, the abnormality detection value is controlled in accordance with the change of the assembled battery 1 side voltage (V), the power supply voltage of the differential output unit 6, the measurement voltage range, and the like. You can keep getting. As a result, the abnormality determination that is the feature of the present invention can be performed with high reliability and the processing time can be shortened.

  Furthermore, the threshold value can be changed by the output of a thermometer mounted on the assembled battery 1 to prevent erroneous detection of abnormal operation due to a change in battery temperature.

(Embodiment 4)
FIG. 7 is a diagram for explaining a fourth embodiment of the present invention. In the fourth embodiment, within the output range of the differential output voltages V1 and V2, Va (first voltage threshold) is set on the differential output voltage V1 side, and Vb (second voltage threshold) is set on the V2 side. A voltage is set in advance, and when the values of the differential output voltages V1 and V2 exceed these threshold levels, a flag is set for the data in the data processing system by the CPU 10. As shown in FIG. 7, Va and Vb are symmetrical with respect to the initial offset value, that is, | Va−Vmo | = | Vb−Vmo |. When the assembled battery 1 side voltage (V) as an input voltage exceeds this threshold, if the differential output unit 6 is operating normally, the flag set in the data corresponding to the differential output voltages V1 and V2 is It should change at the same time. Therefore, it is possible to detect an abnormality in apparatus operation by detecting whether or not the flags change simultaneously. Table 1 summarizes the state of logic processing in each state of FIG.

以下、表１及び図７により本実施の形態４の動作を説明する。

The operation of the fourth embodiment will be described below with reference to Table 1 and FIG.

Here, when the differential output unit 6 is operating normally, the difference voltage between the differential output voltages V1 and V2 is ΔV, and the region sandwiched between both thresholds is Vlow, that is, ΔV = V1−V2 (Equation 12 )
Vlow = Va−Vb (Equation 13)
Even if ΔV in (Equation 12) is larger or smaller than Vlow in (Equation 13), if there is a flag in the processing data corresponding to each of the differential output voltages V1 and V2, the device operates normally. It shows that. This corresponds to the operation of the time areas (1) to (3) in FIG. For example, as shown in the time domain (4), when the differential output voltage V1 side is operating normally and does not exceed the threshold value Va, an abnormal operation occurs on the voltage V2 side and the voltage V2 exceeds the threshold value Vb. , (Equation 12) even when ΔV is smaller than Vlow, the threshold comparison signal shown in FIG. 7 is in the High region on the V2 side, and therefore the flag exists only in the V2 region. Abnormal operation of the apparatus can be detected.
It is also possible to set a plurality of the above threshold values, and this makes it possible to detect the operation abnormality step by step. For example, an abnormality is detected when a plurality of threshold values are exceeded, and only one threshold value is exceeded. Then, if the abnormality is not detected, the abnormality can be detected more reliably, and the operation abnormality detection logic can be set up so as to reduce the possibility of erroneous detection.

(Embodiment 5)
FIG. 8 explains the processing steps of the fifth embodiment according to the present invention. Even when an abnormality of the differential output unit 6 is detected by the above-described method, it is usually not a complete failure state and measurement is impossible. Therefore, in this case, the presence / absence of a flag is detected in the above-described threshold comparison. For example, as shown in FIG. 7, it is assumed that a flag is generated and an abnormality occurs when the threshold is exceeded. If it is determined that the one that does not cause the error is normal, the output voltage (B in FIG. 8) on the abnormal side is replaced with the output voltage on the normal side (A = Vmo−V2 in FIG. 8), and the differential output It is also possible to make a voltage with the output of the unit 6. According to this method, one of the differential output voltages is processed by replacing the other abnormal output voltage with the other abnormal output voltage, and thus a decrease in accuracy is inevitable. However, the battery pack uses only the normal output voltage. Since the total voltage of 1 can be obtained, it is possible to perform fail-safe processing for abnormal operation of the detection device.

  In each of the embodiments described above, the outputs V1 and V2 of the differential output unit 6 are all voltage outputs, but the same processing can be performed even for current outputs.

The circuit diagram which shows the basic composition of the voltage sensor abnormality detection apparatus by this invention. FIG. 3 is a voltage relationship diagram illustrating the principle of the abnormal operation detection method according to the first embodiment. FIG. 3 is a flowchart showing a procedure of an abnormal operation detection method according to the first embodiment. FIG. 6 is a voltage relationship diagram illustrating the principle of the abnormal operation detection method according to the second embodiment. FIG. 10 is a voltage relationship diagram illustrating the principle of the abnormal operation detection method according to the third embodiment. FIG. 5 is a diagram showing the relationship between an abnormality determination value and an assembled battery side voltage when the abnormality determination value is changed under voltage conditions. FIG. 10 is a voltage change waveform diagram showing the principle of the abnormal operation detection method according to the fourth embodiment. FIG. 10 is a voltage relationship diagram illustrating the principle of the abnormal operation detection method according to the fifth embodiment.

Explanation of symbols

1: assembled battery 2: main relay 3: load 4: switch 5: voltage divider 6: differential output unit 7: chopper 8: differential transformer 9: amplifier 10: CPU
11: A / D port 12: Voltage sensor

Claims (9)

A differential output unit that outputs a first voltage and a second voltage that are opposite in phase with a voltage difference corresponding to an input voltage that is input, and the first voltage and the second voltage that are output from the differential output unit In a voltage sensor abnormality detection method comprising a voltage detection unit that detects the input voltage based on a difference voltage between
The first voltage and the second voltage when the input voltage is greater than 0 with respect to the initial offset voltage that is an intermediate value between the first voltage and the second voltage when the input voltage is 0 And detecting an abnormality in the differential output unit by detecting that the two are asymmetric. The voltage sensor abnormality detection method according to claim 1,
When the input voltage is greater than 0, an absolute value of a difference voltage between the intermediate value between the first voltage and the second voltage output from the differential output unit and the initial offset voltage is set in advance. An abnormality detection method for a voltage sensor, wherein an abnormality of the differential output unit is determined when the first abnormality determination value is exceeded. The voltage sensor abnormality detection method according to claim 1,
Obtaining an absolute value of a first differential voltage that is a difference between the initial offset voltage and one of the first voltage and the second voltage output from the differential output unit, and the initial offset Find the absolute value of the second differential voltage, which is the difference between the voltage and the other one of the first voltage and the second voltage output from the differential output unit,
When the third difference voltage, which is the absolute value of the difference between the absolute value of the first difference voltage and the absolute value of the second difference voltage, is equal to or greater than a preset second abnormality determination value. A method for detecting an abnormality of a voltage sensor, comprising: determining that the differential output unit is abnormal. The voltage sensor abnormality detection method according to claim 1,
A first voltage change amount that is an absolute value of a change amount of each of the first voltage and the second voltage output from the differential output unit when the input voltage is changed by a predetermined voltage; A second voltage change amount is detected, and when the difference between the first voltage change amount and the second voltage change amount is equal to or greater than a preset third abnormality determination value, the differential output unit An abnormality detection method for a voltage sensor, characterized in that the abnormality is determined. An abnormality detection method for a voltage sensor according to any one of claims 1 to 4,
An abnormality detection method for a voltage sensor, wherein the abnormality determination value is changed according to the magnitude of the input voltage. The voltage sensor abnormality detection method according to claim 1,
Two threshold values, a first voltage threshold value and a second voltage voltage threshold value, which are symmetrical with respect to the initial offset voltage, corresponding to the first voltage and the second voltage output from the differential output unit, respectively. Set,
An abnormality of the voltage sensor, wherein the abnormality of the differential output unit is determined when the second voltage is not the second voltage threshold when the first voltage becomes the first voltage threshold. Detection method. It is a voltage sensor abnormality detection method of Claim 6, Comprising: The said input voltage is a voltage output from a battery, Comprising: The temperature detection means which detects the temperature of this battery is provided, The temperature detected by this temperature detection means An abnormality detection method for a voltage sensor, characterized in that the first voltage threshold and the second voltage threshold are changed based on A differential output unit that outputs a first voltage and a second voltage that are opposite to each other with a voltage difference corresponding to an input voltage input from the power source connected to the power source, and the differential output unit In a voltage sensor including a voltage detector that detects the input voltage based on a voltage difference between the output first voltage and the second voltage,
Provided between the power source and the differential output unit, comprising a switch that can switch the connection between the power source and the differential output unit to a disconnected state or a connected state,
With respect to an initial offset voltage that is an intermediate value between the first voltage and the second voltage when the switch is in a disconnected state, a first voltage and a second voltage when the switch is in a connected state, An abnormality detection device for a voltage sensor, comprising abnormality detection means for detecting an abnormality in the differential output unit by detecting that the signal is asymmetric. A voltage sensor comprising the voltage sensor abnormality detection device according to claim 8,
When an abnormality is detected by the abnormality detection means, the apparatus further comprises a specifying means for specifying a voltage at which an abnormality has occurred between the first voltage and the second voltage,
When an abnormality is detected by the abnormality detecting means, the input voltage is detected based on a voltage difference between the other voltage different from the voltage specified by the specifying means and the initial offset voltage. A voltage sensor.

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