JP2017219444A - Gain adjustment device, battery monitoring system and gain adjustment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gain adjustment device capable of accurately measuring current, a battery monitoring system and a gain adjustment method.SOLUTION: A gain adjustment device includes: an amplification unit configured to amplify an output value of a sensor, which outputs an output value according to an input value to be measured; a gain adjustment unit configured to adjust gain of the amplification unit to switch to any measurement range among a plurality of different measurement ranges; an AD conversion unit having predetermined resolution, and configured to convert the output value amplified by the amplification unit into a digital value; and an acquisition unit configured to acquire a signal for estimating occurrence of an event that the input value of the sensor is equal to or more than a predetermined value. The gain adjustment unit is configured to adjust the gain of the amplification unit based on the signal acquired by the acquisition unit.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a gain adjusting device, a battery monitoring system including the gain adjusting device, and a gain adjusting method.

  In recent years, vehicles such as HEV (Hybrid Electric Vehicle) and EV (Electric Vehicle) are becoming widespread. HEV and EV are equipped with secondary batteries. In such a vehicle, charging and discharging of the secondary battery are repeatedly switched as the vehicle travels. In order to monitor the state of the secondary battery such as the internal resistance or the charging rate (SOC), it is necessary to accurately measure the current flowing through the secondary battery.

  As a method of measuring the current of the secondary battery, for example, the range of the current flowing through the secondary battery is divided into a current integration range which is a region around 0A and a large current range which is another region. A current measurement method is disclosed in which the output sensitivity of the current sensor is switched so that the output sensitivity of the current integration range is higher than the output sensitivity of the large current range (see Patent Document 1).

JP 2007-327823 A

  However, in the method disclosed in Patent Document 1, the output sensitivity for each range obtained by dividing the current range is set separately, and the current measured by the current sensor is relatively steady. Is assumed. For this reason, when the current changes sharply, the switching of the output sensitivity cannot follow, and the current may not be measured accurately.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a gain adjustment device capable of accurately measuring a current, a battery monitoring system including the gain adjustment device, and a gain adjustment method. .

  The gain adjustment device according to the embodiment of the present invention adjusts the gain of the amplification unit that amplifies the output value of the sensor that outputs the output value according to the input value to be measured, A gain adjusting unit that switches to a large or small measuring range among a plurality of measuring ranges having different ranges; an AD converting unit that has a predetermined resolution and converts an output value amplified by the amplifying unit into a digital value; and the sensor The gain adjustment unit adjusts the gain of the amplification unit based on the signal acquired by the acquisition unit.

  The battery monitoring system according to the embodiment of the present invention includes the gain adjusting device according to the above-described embodiment and a sensor that measures the current of the secondary battery.

  A gain adjustment method according to an embodiment of the present invention is a gain adjustment method performed by a gain adjustment device, and an amplification unit amplifies the output value of a sensor that outputs an output value corresponding to an input value to be measured, The gain adjustment unit adjusts the gain of the amplifying unit to switch to a large or small measuring range among a plurality of measuring ranges having different ranges, and AD conversion having a predetermined resolution for the output value amplified by the amplifying unit The acquisition unit acquires a signal that is converted into a digital value and estimates the occurrence of an event in which the input value of the sensor is greater than or equal to a predetermined value, and the gain adjustment unit is based on the acquired signal Adjust the gain.

  According to the present invention, current can be measured with high accuracy.

It is a block diagram which shows an example of a structure of the principal part of the vehicle carrying the battery monitoring apparatus as a gain adjustment apparatus of this Embodiment. It is explanatory drawing which shows an example of the relationship between the measurement range and sensitivity which are measured with the current sensor based on the gain adjustment by the battery monitoring apparatus of this Embodiment. It is explanatory drawing which shows an example of the switching method of the measurement range by the battery monitoring apparatus of this Embodiment. It is explanatory drawing which shows the 1st example of switching of the measurement range based on gain adjustment by the battery monitoring apparatus of this Embodiment. It is explanatory drawing which shows the 2nd example of switching of the measurement range based on the gain adjustment by the battery monitoring apparatus of this Embodiment. It is explanatory drawing which shows the 3rd example of switching of the measurement range based on gain adjustment by the battery monitoring apparatus of this Embodiment. It is a flowchart which shows an example of the process sequence of the battery monitoring apparatus of this Embodiment.

[Description of Embodiment of Present Invention]
The gain adjustment device according to the embodiment of the present invention adjusts the gain of the amplification unit that amplifies the output value of the sensor that outputs the output value according to the input value to be measured, A gain adjusting unit that switches to a large or small measuring range among a plurality of measuring ranges having different ranges; an AD converting unit that has a predetermined resolution and converts an output value amplified by the amplifying unit into a digital value; and the sensor The gain adjustment unit adjusts the gain of the amplification unit based on the signal acquired by the acquisition unit.

  The battery monitoring system according to the embodiment of the present invention includes the gain adjusting device according to the above-described embodiment and a sensor that measures the current of the secondary battery.

  A gain adjustment method according to an embodiment of the present invention is a gain adjustment method performed by a gain adjustment device, and an amplification unit amplifies the output value of a sensor that outputs an output value corresponding to an input value to be measured, The gain adjustment unit adjusts the gain of the amplifying unit to switch to a large or small measuring range among a plurality of measuring ranges having different ranges, and AD conversion having a predetermined resolution for the output value amplified by the amplifying unit The acquisition unit acquires a signal that is converted into a digital value and estimates the occurrence of an event in which the input value of the sensor is greater than or equal to a predetermined value, and the gain adjustment unit is based on the acquired signal Adjust the gain.

  The amplifying unit amplifies the output value output from the sensor according to the input value to be measured. The sensor is, for example, a current sensor, which converts a current (input value) into a voltage (output value) and outputs it. The gain adjusting unit adjusts the magnitude of the gain of the amplifying unit to switch to a larger or smaller measurement range among a plurality of measurement ranges having different ranges. Assume that the sensor measures the charge / discharge current of the battery. A plurality of measurement ranges having different ranges are provided, for example, as four measurement ranges having different ranges such as 0A to 200A, 0A to 400A, 0A to 800A, and 0A to 1600A. Can do. In addition, since predetermined charging control is performed for the charging current of the battery, the measurement range at the time of charging can be set to, for example, 0A to 200A.

  The AD conversion unit has a predetermined resolution (for example, 12 bits, 16 bits, etc.), and converts the output value amplified by the amplification unit into a digital value.

  For example, when the measurement range of the sensor is small (for example, 0A to 200A), the amplification unit amplifies the output value output from the sensor and outputs a predetermined value (for example, 0V to 5V) to the AD conversion unit. In this case, the gain adjusting unit adjusts the gain of the amplifying unit to a gain sufficient to amplify the voltage corresponding to 200 A to 5 V (the gain is large). If the AD conversion unit can decompose the input into 2000 steps, for example, the output of the AD conversion unit decomposes 200 A into 2000 steps, so the measurement sensitivity is 100 mA. When the measurement range of the sensor is large (for example, 0A to 1600A), the amplification unit amplifies the output value output from the sensor and outputs a predetermined value (for example, 0V to 5V) to the AD conversion unit. In this case, the gain adjusting unit adjusts the gain of the amplifying unit to a gain sufficient to amplify the voltage corresponding to 1600 A to 5 V (the gain is small). If the AD conversion unit can decompose the input into 2000 steps, for example, the output of the AD conversion unit decomposes 1600A into 2000 steps, so that the measurement sensitivity is 800 mA.

  That is, when the measurement range of the sensor is small, the sensitivity of measurement is increased by increasing the gain. In addition, when the measurement range of the sensor is large, the sensitivity of measurement is lowered by reducing the gain.

  An acquisition part acquires the signal which estimates generation | occurrence | production of the event in which the input value of a sensor becomes more than predetermined value. When the gain adjustment device is used for in-vehicle use, an event that exceeds a predetermined value is, for example, an event in which the battery discharge current suddenly increases when the engine is started (cold start, restart, etc.) It can be. The acquisition of a signal for estimating the occurrence of an event includes, for example, acquisition of ignition information, acquisition of timing when a predetermined stop time has elapsed when the vehicle is considered to be stopped from the transition of the battery current value, and the idling stop state is It is possible to acquire the timing when a predetermined time has passed.

  The gain adjustment unit adjusts the gain of the amplification unit based on the signal acquired by the acquisition unit. For example, the gain is decreased so that the measurement range of the sensor becomes the maximum range. With the above configuration, it is possible to increase the sensor's measurement range by assuming a sudden current change such as a cold start or restart in advance, so that it can properly follow a rapidly changing current. By adjusting the gain, the current can be measured with high accuracy by preventing the situation where the current cannot be measured.

  In the gain adjustment device according to the embodiment of the present invention, when the gain adjustment unit acquires the signal, the gain adjustment unit reduces the gain of the amplification unit and switches the measurement range of the sensor to the maximum range.

  When acquiring the signal, the gain adjusting unit reduces the gain of the amplifying unit and switches the measurement range of the sensor to the maximum range. As a result, even when the current suddenly changes such as cold start or restart, the current can be measured without causing a loss of current measurement.

  The gain adjustment device according to an embodiment of the present invention has a predetermined threshold value in each of the plurality of measurement ranges, and the gain adjustment unit has an input value of the sensor larger than the threshold value in an arbitrary measurement range. In such a case, the gain of the amplifying unit is adjusted to switch to the measurement range having the next largest range after the arbitrary measurement range.

  Each of the plurality of measurement ranges has a predetermined threshold value. For example, the threshold value in the measurement range 0A to 200A is set to Ith1, the threshold value Ith2 in the measurement range 0A to 400A (> Ith1), and the threshold value in the measurement range 0A to 800A is set to Ith3 (> Ith2).

  When the input value of the sensor becomes larger than the threshold value in an arbitrary measurement range, the gain adjustment unit adjusts the gain of the amplification unit and switches to the measurement range having the next largest range after the arbitrary measurement range. For example, assuming that the current measurement range is 0A to 200A, when the current I measured by the sensor is larger than the threshold value Ith1, the measurement range is switched from 0A to 200A to 0A to 400A. Further, assuming that the current measurement range is 0A to 400A, when the current I measured by the sensor becomes larger than the threshold value Ith2, the measurement range is switched from 0A to 400A to 0A to 800A.

  With the above-described configuration, the measurement range can be switched so as to increase the measurement range by adjusting the gain according to the increase in current, so that the current can be measured without causing loss of current measurement.

  In the gain adjusting device according to the embodiment of the present invention, the gain adjusting unit counts the number of times that the gain of the amplifying unit is adjusted, and the number of times counted by the counting unit in a predetermined time is a predetermined number or more. And an output unit for outputting a predetermined result.

  The counting unit counts the number of times that the gain adjustment unit adjusts the gain of the amplification unit. The output unit outputs a predetermined result when the number of times counted by the counting unit in a predetermined time is equal to or greater than a predetermined number. The predetermined time can be, for example, 1 minute, 2 minutes, etc., but is not limited to these values. Further, the predetermined number of times can be two times, three times, etc., but is not limited to these numerical values. The predetermined result refers to notifying a user (driver, passenger) of an alarm or a warning, for example.

  In an electric circuit connecting a battery and an electric load or the like, a phenomenon called a micro ground fault in which a relatively large current flows suddenly or intermittently appears as a sign before a ground fault or a short circuit phenomenon occurs. When the micro ground fault occurs, a current change in a different manner from the normal charge / discharge cycle in which a phenomenon in which a sudden large current flows is repeated in a relatively short time occurs. With the above-described configuration, it is possible to notify the occurrence of a fine ground fault following an irregular current change such as a fine ground fault.

  The gain adjustment device according to the embodiment of the present invention provides a predetermined result when the gain adjustment unit reduces the gain of the amplification unit and switches the measurement range to the maximum range when the signal is not acquired. Is provided.

  The output unit outputs a predetermined result when the gain adjustment unit reduces the gain of the amplification unit and switches the measurement range to the maximum range when no signal is acquired. When a signal is not acquired, that is, when a cold start, a restart, etc. do not occur, it is considered that the measurement range is not switched to the maximum range in a normal charge / discharge state. The predetermined result refers to notifying a user (driver, passenger) of an alarm or a warning, for example.

  In an electric circuit connecting a battery and an electric load or the like, a phenomenon called a micro ground fault in which a relatively large current flows suddenly or intermittently appears as a sign before a ground fault or a short circuit phenomenon occurs. When the micro ground fault occurs, a current change in a different manner from the normal charge / discharge cycle in which a phenomenon in which a sudden large current flows is repeated in a relatively short time occurs. With the above-described configuration, it is possible to notify the occurrence of a fine ground fault following an irregular current change such as a fine ground fault.

  In the gain adjusting device according to the embodiment of the present invention, the gain adjusting unit stops adjusting the predetermined stop time gain when the gain of the amplifying unit is adjusted.

  The gain adjustment unit stops adjusting the predetermined stop time gain when the gain of the amplification unit is adjusted. The predetermined stop time can be, for example, 1 minute, but is not limited thereto. Since the adjustment of the predetermined stop time gain is stopped, it is possible to suppress a situation in which gain adjustment becomes difficult due to an irregular change in current, and current measurement is continuously lost.

[Details of the embodiment of the present invention]
Hereinafter, a battery monitoring system and a gain adjusting device according to embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an example of a configuration of a main part of a vehicle equipped with a battery monitoring device 100 as a gain adjusting device of the present embodiment. As shown in FIG. 1, the vehicle includes a battery 50, relays 61 and 63, a generator (ALT) 62, a starter motor (ST) 64, and an electric load 65 in addition to the battery monitoring device 100. The battery monitoring system includes a battery monitoring device 100, a battery 50 (at least a current sensor 53), and the like.

  The battery 50 is, for example, a lead battery, and a plurality of cells 51 are connected in series or series-parallel. The battery 50 includes a voltage sensor 52 and a current sensor 53 as a sensor. The voltage sensor 52 detects the voltage of each cell 51 and the voltage across the battery 50, and outputs the detected voltage to the battery monitoring device 100. The current sensor 53 is composed of, for example, a shunt resistor or a hall sensor, and detects the charging current and discharging current of the battery 50. The current sensor 53 outputs the detected current to the battery monitoring device 100.

  The battery 50 supplies power to the electric load 65 of the vehicle when the relay 61 is turned on, and supplies power for driving the starter motor 64 when the relay 63 is turned on. The generator 62 generates electric power by the rotation of the engine of the vehicle and outputs direct current by a rectifier circuit provided inside to charge the battery 50. The battery monitoring device 100 turns the relays 61 and 63 on and off.

  As shown in FIG. 1, the battery monitoring apparatus 100 includes a control unit 10 that controls the entire apparatus, an amplification unit 11, an AD conversion unit 12, a buffer 13, an acquisition unit 14, a gain adjustment unit 15, a counting unit 16, and an output unit 17. The voltage monitoring unit 18 is provided. The gain adjustment apparatus according to the present embodiment includes at least an amplification unit 11, a gain adjustment unit 15, an AD conversion unit 12, and an acquisition unit 14.

  The amplifying unit 11 amplifies the output value output from the current sensor 53 according to the input value to be measured. For example, the amplification unit 11 acquires the output value of the current sensor 53, amplifies the acquired output value based on the adjusted gain, and outputs the amplified output value to the AD conversion unit 12.

  The gain adjustment unit 15 adjusts the magnitude of the gain of the amplification unit 11 and switches the measurement range to a larger or smaller measurement range among a plurality of measurement ranges having different ranges. A plurality of measurement ranges having different ranges are provided, for example, as four measurement ranges having different ranges such as 0A to 200A, 0A to 400A, 0A to 800A, and 0A to 1600A. Can do. In addition, since predetermined charging control is performed for the charging current of the battery 50, the measurement range during charging can be set to, for example, 0A to 200A.

  The AD converter 12 has a predetermined resolution (for example, 12 bits, 16 bits, etc.), and converts the output value amplified by the amplifier 11 into a digital value at a predetermined sampling period (for example, 10 ms). . The AD conversion unit 12 stores the converted digital value in the buffer 13.

  The controller 10 can acquire the current value measured by the current sensor 53 by reading the digital value stored in the buffer 13.

  The voltage monitoring unit 18 acquires the voltage of the battery 50 (including the voltage of the cell 51) at a predetermined sampling period (for example, 10 ms). The voltage monitoring unit 18 outputs the acquired voltage to the control unit 10.

  FIG. 2 is an explanatory diagram showing an example of the relationship between the measurement range and sensitivity measured by the current sensor 53 based on gain adjustment by the battery monitoring apparatus 100 of the present embodiment. Modes include charging and discharging. As shown in FIG. 2, for example, when the charge / discharge current of the battery 50 is measured by the current sensor 53, the measurement ranges for measuring the current include a plurality of measurement ranges having different ranges. In the example of FIG. 2, four measurement ranges such as 0A to 200A, 0A to 400A, 0A to 800A, and 0A to 1600A are provided (for convenience, in FIG. Is the maximum value). In addition, since predetermined charging control is performed on the charging current of the battery, the measurement range during charging can be set to, for example, 0A to 200A. In addition, the measurement range illustrated in FIG. 2 is an example, and is not limited to these values.

  If the current sensor 53 is a shunt resistor, for example, if the resistance value of the shunt resistor is 1 mΩ, the current sensor 53 outputs a voltage of 0.2 V when the current is 200 A. Similarly, when the current is 400 A, 800 A, and 1600 A, the current sensor 53 outputs voltages of 0.4 V, 0.8 V, and 1.6 V, respectively. The resistance value of the shunt resistor is an example and is not limited to 1 mΩ.

  When the measurement range is 0 A to 200 A, the amplifying unit 11 amplifies the output value (voltage value) 0 V to 0.2 V output from the current sensor 53 and supplies a predetermined value (for example, 0 V to 5 V) to the AD converting unit 12. Output. In this case, the gain adjusting unit 15 adjusts the gain of the amplifying unit 11 to be a gain 25 (the gain is large) sufficient to amplify the voltage 0.2V corresponding to 200A to 5V. For example, if the AD conversion unit 12 can decompose the input into 2000 steps, the output of the AD conversion unit 12 decomposes 200 A into 2000 steps, so that the measurement sensitivity is 100 mA.

  Here, if the resolution of the AD conversion unit 12 is, for example, 12 bits, the input can be decomposed into 4096 stages. If half the resolution is used for both charging and discharging, for example, in the case of discharging, it can be broken down into 2048 stages, but in the example of FIG. .

  When the measurement range is 0A to 400A, the amplifying unit 11 amplifies the output value (voltage value) 0V to 0.4V output from the current sensor 53 and converts the predetermined value (for example, 0V to 5V) into the AD converting unit. 12 is output. In this case, the gain adjustment unit 15 adjusts the gain of the amplification unit 11 so that the gain becomes 12.5 which is sufficient to amplify the voltage 0.4V corresponding to 400A to 5V. Since the output of the AD converter 12 decomposes 400 A into 2000 steps, the measurement sensitivity is 200 mA.

  When the measurement range is 0A to 800A, the amplifying unit 11 amplifies the output value (voltage value) 0V to 0.8V output from the current sensor 53 and converts the predetermined value (for example, 0V to 5V) into the AD converting unit. 12 is output. In this case, the gain adjusting unit 15 adjusts the gain of the amplifying unit 11 to be a gain 6.25 sufficient to amplify the voltage 0.8V corresponding to 800A to 5V. Since the output of the AD converter 12 decomposes 800A into 2000 steps, the measurement sensitivity is 400 mA.

  When the measurement range is 0A to 1600A, the amplifying unit 11 amplifies the output value (voltage value) 0V to 1.6V output from the current sensor 53 and converts a predetermined value (for example, 0V to 5V) into an AD conversion unit. 12 is output. In this case, the gain adjusting unit 15 adjusts the gain of the amplifying unit 11 to be a gain 3.125 (the gain is small) enough to amplify the voltage 1.6V corresponding to 1600A to 5V. Since the output of the AD converter 12 decomposes 1600 A into 2000 steps, the measurement sensitivity is 800 mA.

  The acquisition unit 14 acquires a signal that estimates the occurrence of an event in which the input value of the current sensor 53 is greater than or equal to a predetermined value. When the battery monitoring apparatus 100 is used for in-vehicle use, an event that is equal to or greater than a predetermined value is, for example, that the discharge current of the battery 50 rapidly increases when the engine is started (cold start, restart, etc.). Event. Acquisition of a signal for estimating the occurrence of an event includes, for example, acquisition of ignition information, acquisition of timing when a predetermined stop time has elapsed when the vehicle is considered to be stopped from the transition of the current value of the battery 50, idling stop state Acquisition of timing when a predetermined time elapses.

  The gain adjustment unit 15 adjusts the gain of the amplification unit 11 based on the signal acquired by the acquisition unit 14. With the above-described configuration, it is possible to increase the measurement range of the current sensor 53 on the assumption that the current suddenly changes, such as a cold start or restart, and accordingly appropriately follow the rapidly changing current. Thus, the gain can be adjusted to prevent a situation where current cannot be measured (loss of current measurement) and the current can be measured accurately.

  In addition, when the acquisition unit 14 acquires a signal, the gain adjustment unit 15 reduces the gain of the amplification unit 11 and switches the measurement range of the current sensor 53 to the maximum range. As a result, even when the current suddenly changes such as cold start or restart, the current can be measured without causing a loss of current measurement.

  FIG. 3 is an explanatory diagram showing an example of a measurement range switching method by the battery monitoring apparatus 100 of the present embodiment. The upper diagram in FIG. 3 shows an example of the transition of the discharge current, and the lower diagram shows the transition of the measurement range switching. Each measurement range of the current sensor 53 has a predetermined threshold for adjusting the gain and switching the measurement range. For example, the threshold value in the measurement range 0A to 200A is set to Ith1, the threshold value Ith2 in the measurement range 0A to 400A (> Ith1), and the threshold value in the measurement range 0A to 800A is set to Ith3 (> Ith2). Note that Ith3 is not shown in FIG.

  The threshold value Ith1 can be set to 150A, the threshold value Ith2 can be set to 350A, and the threshold value Ith3 can be set to 700A, but is not limited to these numerical values.

  When the input value of the current sensor 53 becomes larger than the threshold value in an arbitrary measurement range, the gain adjustment unit 15 adjusts the gain of the amplification unit 11 and switches to the measurement range having the next largest range after the arbitrary measurement range.

  For example, as shown in FIG. 3, when the current measurement range is 0A to 200A, when the current I measured by the current sensor 53 is larger than the threshold value Ith1, the measurement range is changed from 0A to 200A to 0A to 400A. Switch to. Further, assuming that the current measurement range is 0A to 400A, when the current I measured by the current sensor 53 is larger than the threshold value Ith2, the measurement range is switched from 0A to 400A to 0A to 800A.

  With the above configuration, the measurement range can be switched so that the measurement range becomes larger by adjusting the gain according to the increase in current, so even if the current fluctuates, the current can be measured without causing loss of current measurement. can do.

  In the example of FIG. 3, the measurement range is switched when the current measured by the current sensor 53 increases. However, the measurement range is switched similarly when the current measured by the current sensor 53 decreases. Can do. For example, when the current measurement range is 0A to 1600A, when the current I measured by the current sensor 53 is smaller than the threshold Ith3 in the measurement range 0A to 800A, which is the next smaller than the current measurement range, the measurement range Is switched from 0A to 1600A to 0A to 800A. The same applies to other measurement ranges.

  FIG. 4 is an explanatory diagram showing a first example of measurement range switching based on gain adjustment by the battery monitoring apparatus 100 of the present embodiment. The upper diagram in FIG. 4 shows an example of the transition of the charge / discharge current, and the lower diagram shows the transition of the measurement range switching. In the lower diagram, the measurement range between the maximum ranges indicates a required measurement range other than the maximum range.

  As shown in the upper diagram of FIG. 4, the vehicle is initially parked with the engine turned off. When the ignition is turned on (cold start) and the engine is started, a large discharge current flows. Thereafter, charging / discharging of the battery 50 is performed according to the driving state of the vehicle. When idling is stopped when waiting for a signal or the like, the discharge current of the battery 50 becomes small (for example, a current value that is considered to be that the vehicle is stopped). When the engine is started by restarting in the idling stop state, a large discharge current flows.

  In this embodiment, when a signal for estimating a cold start and a signal for estimating a restart are acquired (timing indicated by a broken line in FIG. 4), for example, the measurement range is switched to the maximum range. Even when the current changes suddenly, such as when restarted, the current can be measured without causing a loss of current measurement.

  Further, when the gain adjustment unit 15 adjusts the gain of the amplification unit 11 to switch the measurement range, the gain adjustment unit 15 stops adjusting the predetermined stop time gain. In the example of FIG. 4, the maximum range is maintained during the stop time indicated by the arrow, and switching to a measurement range other than the maximum range is stopped. The predetermined stop time can be, for example, 30 seconds, 1 minute, but is not limited to this. Since the adjustment of the predetermined stop time gain is stopped, it is possible to suppress a situation in which gain adjustment becomes difficult due to an irregular change in current, and current measurement is continuously lost.

  FIG. 5 is an explanatory diagram showing a second example of measurement range switching based on gain adjustment by the battery monitoring apparatus 100 of the present embodiment. The upper diagram of FIG. 5 shows an example of the transition of the charge / discharge current, and the lower diagram shows the transition of the measurement range switching. The current transition in the figure shows a situation where a fine ground fault occurs. In an electric circuit that connects the battery 50 and an electric load or the like, a phenomenon referred to as a fine ground fault in which a relatively large current flows suddenly or intermittently appears as a sign before a ground fault or a short-circuit phenomenon occurs. When the micro ground fault occurs, a current change in a different manner from the normal charge / discharge cycle in which a phenomenon in which a sudden large current flows is repeated in a relatively short time occurs.

  As shown in FIG. 5, the current (discharge current) becomes larger than the threshold value Ith2 at the timing when the fine ground fault occurs. Then, at a timing when the current (discharge current) becomes larger than the threshold value Ith2 (threshold value in the measurement range 0A to 400A), the gain adjusting unit 15 adjusts the gain to set the measurement range to a predetermined measurement range (for example, 0A to 800A). Switch to. The measurement range other than the predetermined measurement range can be set to, for example, 0A to 200A according to the charge / discharge current.

  The counting unit 16 counts the number of times that the gain adjusting unit 15 adjusts the gain of the amplifying unit 11 to switch the measurement range.

  The output unit 17 outputs a predetermined result when the number of times counted by the counting unit 16 in the predetermined time T is equal to or greater than the predetermined number. The predetermined time T can be, for example, 1 minute, 2 minutes, etc., but is not limited to these numerical values. Further, the predetermined number of times can be two times, three times, etc., but is not limited to these numerical values. The predetermined result refers to notifying a user (driver, passenger) of an alarm or a warning, for example.

  If the predetermined number of times is, for example, 3 times, the output unit 17 outputs an alarm or warning when a fine ground fault occurs 3 times during the predetermined time T. With the above-described configuration, it is possible to notify the occurrence of a fine ground fault following an irregular current change such as a fine ground fault.

  FIG. 6 is an explanatory diagram showing a third example of measurement range switching based on gain adjustment by the battery monitoring apparatus 100 of the present embodiment. The upper diagram of FIG. 6 shows an example of the transition of the charge / discharge current, and the lower diagram shows the transition of the measurement range switching. The current transition in the figure shows a situation where a fine ground fault occurs.

  As shown in FIG. 6, the current (discharge current) becomes larger than the threshold value Ith3 at the timing when the fine ground fault occurs. Then, at a timing when the current (discharge current) becomes larger than the threshold value Ith3 (threshold value in the measurement range 0A to 800A), the gain adjustment unit 15 adjusts the gain and switches the measurement range to the maximum range (for example, 0A to 1600A). . The measurement range other than the maximum range can be set to 0 A to 200 A, for example, depending on the charge / discharge current.

  The output unit 17 outputs a predetermined result when the gain adjustment unit 15 adjusts the gain of the amplification unit 11 to switch the measurement range to the maximum range when the acquisition unit 14 has not acquired a signal. When a signal is not acquired, that is, when a cold start, a restart, etc. do not occur, it is considered that the measurement range is not switched to the maximum range in a normal charge / discharge state. Therefore, if the measurement range is switched to the maximum range in a situation where no cold start or restart occurs, it is considered that a fine ground fault has occurred. With the above-described configuration, it is possible to notify the occurrence of a fine ground fault following an irregular current change such as a fine ground fault.

  FIG. 7 is a flowchart showing an example of a processing procedure of the battery monitoring apparatus 100 of the present embodiment. Hereinafter, for the sake of convenience, the subject of processing will be described as the control unit 10. The control unit 10 sets the measurement range of the current sensor 53 to an initial value (for example, 0 A to 200 A) (S11), and measures the current at a predetermined sampling period (for example, 10 ms) (S12).

  The control unit 10 determines whether or not a cold start or restart occurrence estimation signal has been acquired (S13). If the generation estimation signal has not been acquired (NO in S13), the measured current value is the current measurement. It is determined whether or not it is larger than the threshold value within the range (S14). When the measured current value is larger than the threshold within the current measurement range (YES in S14), the control unit 10 switches the measurement range to the next larger measurement range (S15).

  The control unit 10 determines whether or not the maximum range has been switched (S16). If the maximum range has not been switched (NO in S16), it is determined whether or not the number of times the measurement range is switched is greater than or equal to the predetermined number in a predetermined time. Determine (S17). When the number of measurement range switching times is equal to or greater than the predetermined number (YES in S17), the control unit 10 outputs an alarm (S18) and performs the process of step S23 described later.

  If the number of measurement range switching times is not equal to or greater than the predetermined number (NO in S17), the control unit 10 performs the process of step S23 described later without performing the process of step S18. When switching to the maximum range (YES in S16), the control unit 10 performs the process of step S18.

  When the measured current value is not larger than the threshold value in the current measurement range (NO in S14), the control unit 10 determines whether or not the measured current value is smaller than the threshold value in the next smaller measurement range than the current measurement range. Is determined (S19). If the measured current value is smaller than the threshold value in the next smaller measurement range than the current measurement range (YES in S19), the control unit 10 switches the measurement range to the next smaller measurement range (S20), and the process of step S17 I do.

  When the measured current value is not smaller than the threshold value in the measurement range that is the next smaller than the current measurement range (NO in S19), the control unit 10 performs the process of step S23 described later without switching the measurement range.

  When the generation estimation signal is acquired (YES in S13), the control unit 10 switches the measurement range to the maximum range (S21) and determines whether the stop time has elapsed (S22). When the stop time has not elapsed (NO in S22), the control unit 10 performs the process of step S22. The gain adjustment is stopped until the stop time elapses.

  When the stop time has elapsed (YES in S22), the control unit 10 determines whether or not to end the process (S23). When the process is not ended (NO in S23), the process from step S12 is continued. When the process is to be ended (YES in S23), the control unit 10 ends the process.

  In the present embodiment, battery 50 is not limited to a lead battery, and may be another battery (for example, a lithium ion battery).

  The embodiments and examples disclosed above should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above embodiments and examples but by the scope of claims, and is intended to include all modifications and variations within the meaning and scope equivalent to the scope of claims. .

DESCRIPTION OF SYMBOLS 10 Control part 11 Amplification part 12 AD conversion part 13 Buffer 14 Acquisition part 15 Gain adjustment part 16 Count part 17 Output part 18 Voltage monitoring part 50 Battery 51 Cell 52 Voltage sensor 53 Current sensor 100 Battery monitoring apparatus

Claims (8)

An amplifier for amplifying the output value of the sensor that outputs an output value corresponding to the input value to be measured;
A gain adjustment unit that adjusts the magnitude of the gain of the amplification unit and switches the measurement range to a larger or smaller measurement range among a plurality of measurement ranges having different ranges.
An AD conversion unit that has a predetermined resolution and converts the output value amplified by the amplification unit into a digital value;
An acquisition unit for acquiring a signal for estimating the occurrence of an event in which an input value of the sensor is a predetermined value or more,
The gain adjusting unit is
A gain adjusting device that adjusts the gain of the amplifying unit based on the signal acquired by the acquiring unit. The gain adjusting unit is
The gain adjusting device according to claim 1, wherein when the signal is acquired, the gain of the amplification unit is reduced to switch the measurement range of the sensor to the maximum range. A predetermined threshold value in each of the plurality of measurement ranges;
The gain adjusting unit is
3. The switch according to claim 2, wherein when the input value of the sensor becomes larger than the threshold within an arbitrary measurement range, the gain of the amplification unit is adjusted to switch to a measurement range having the next largest range after the arbitrary measurement range. Gain adjustment device. A counting unit for counting the number of times the gain adjusting unit adjusts the gain of the amplifying unit;
The gain adjusting apparatus according to claim 3, further comprising: an output unit that outputs a predetermined result when the number of times counted by the counting unit in a predetermined time is a predetermined number or more.   The output unit that outputs a predetermined result when the gain adjustment unit reduces the gain of the amplification unit and switches the measurement range to the maximum range when the signal is not acquired. 4. The gain adjusting device according to 3. The gain adjusting unit is
The gain adjusting apparatus according to any one of claims 2 to 5, wherein when the gain of the amplifying unit is adjusted, adjustment of a predetermined stop time gain is stopped.   A battery monitoring system comprising: the gain adjusting device according to any one of claims 1 to 6; and a sensor that measures a current of the secondary battery. A gain adjustment method performed by a gain adjustment device,
The amplification unit amplifies the output value of the sensor that outputs the output value according to the input value to be measured,
The gain adjustment unit adjusts the magnitude of the gain of the amplifying unit, and switches to a large or small measurement range among a plurality of measurement ranges having different ranges.
An AD conversion unit having a predetermined resolution converts the output value amplified by the amplification unit into a digital value,
The acquisition unit acquires a signal for estimating the occurrence of an event in which the input value of the sensor is equal to or greater than a predetermined value,
The gain adjusting unit is
A gain adjustment method for adjusting the gain of the amplification unit based on the acquired signal.

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