JP2012063246A - Calibration apparatus for current sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a calibration apparatus of a current sensor for calibrating an offset error of the current sensor.SOLUTION: The calibration apparatus of the current sensor includes: a current sensor 7 for measuring a charge and discharge current value i of a battery 1; a voltage sensor 13 for measuring a both-end voltage value V of an electric element 10 serially placed between the battery 1 and a load 6; state estimation means 17 to which the charge and discharge current value i measured by the current sensor 7 and the both-end voltage V measured by the voltage sensor 13 are inputted and which estimates an internal resistance value R of the electric element 10 on the basis of an equivalent circuit model 17A of the internal resistance of the electric element 10; and current calculation means 17 for calculating a current estimation value I from the internal resistance value R estimated in the state estimation means 17 and the voltage value V detected by the voltage sensor to define a result as a calibrated current value of the current sensor 7.

Description

  The present invention relates to a calibration device for a current sensor that detects a charge / discharge current of a battery of an electric vehicle or the like.

  For example, in an electric vehicle or a hybrid electric vehicle, electric power is supplied (discharged) to an electric motor used to drive these vehicles, or an electric motor that causes braking energy to function as a generator or on the ground. A rechargeable battery (secondary battery) is used to store electric energy by charging from an installed power source.

In this case, in order to keep the battery in an optimum state for a long period of time and to optimally control the electric motor, it is necessary to constantly monitor the charge / discharge current of the battery with a current sensor.
As this current sensor, a current sensor using the Hall effect is often used when a change in current charged / discharged is large as in an electric vehicle or the like.
In such a current sensor, in general, although the battery current does not flow (that is, current = 0 ampere), the detected current value is offset by a constant current, and an error is generated accordingly. There are many.

Therefore, attempts have been made to increase the accuracy of the current detection value by reducing the offset error of the current sensor.
One of them is that multiplex communication on the LAN (Local Area Network) is not performed between the vehicle-mounted electronic control units immediately after the ignition key is turned off while the battery is not charged. The current detection value detected in the state and the output of the current sensor in a predetermined standard characteristic regarding the output of the current sensor when the current flowing on the power supply line between the load including the battery and the electronic control unit is zero; Is determined and stored as an offset error adjustment, and is used when the ignition key is turned on next time (see, for example, Patent Document 1).

  As another device, there are a current detection resistor (so-called shunt resistor) connected in series with the battery, an amplifier that amplifies the voltage across the resistor, and a main current sensor that detects the current flowing through the battery with the output voltage of the amplifier. And a correction circuit having a calculation circuit for correcting the measurement value, and in a state where the output voltage of the amplifier becomes a set voltage, the correction circuit calculates the current flowing from the output voltage of the amplifier to the current detection resistor, A device that corrects the measured value of the main current sensor by comparing the calculated value and the detected current value of the main current sensor is known (for example, see Patent Document 2).

JP 2004-325235 A Japanese Patent No. 3691364

However, the conventional current sensor calibration apparatus has the following problems.
First, in the former current sensor calibration device, the current sensor error can be corrected only under specific conditions when the ignition key is OFF. However, there is a problem that the offset error cannot be sufficiently corrected, and a decrease in detection accuracy cannot be avoided.

  In the latter current sensor calibration device, it is necessary to add a new current detection resistor, and the temperature of the resistor increases with the passage of time. Therefore, there is a problem in that the correction is complicated in consideration of the change in the internal resistance of the device.

  The present invention has been made paying attention to the above-mentioned problems, and the object of the present invention is to offset the current sensor offset error that changes each time during running or charging without adding a shunt resistor or the like separately. An object of the present invention is to provide a calibration device for a current sensor that can calibrate the charge / discharge current measured by the current sensor so as to reduce the current.

For this purpose, the current sensor calibration device according to the present invention comprises:
A current sensor for measuring the charge / discharge current value of the battery;
A voltage sensor for measuring a voltage value across an electric element arranged in series between the battery and the load;
A state estimating means for inputting the charge / discharge current value measured by the current sensor and the both-end voltage measured by the voltage sensor, and estimating the internal resistance value of the electric element based on an equivalent circuit model of the internal resistance of the electric element;
Current calculating means for calculating a current calibration value of the current sensor from the internal resistance value estimated by the state estimating means and the voltage values detected by the voltage sensor;
It is provided with.

  In the current sensor calibration apparatus according to the present invention, the internal resistance value is estimated from the charge / discharge current value measured by the current sensor and the both-end voltage measured by the voltage sensor using the equivalent circuit model of the internal resistance of the electric element, Since this value is used to divide the measured value of the voltage across the electrical element to obtain the current calibration value, using the electrical element that was originally required, without adding a shunt resistor, etc. Even during charging or charging, the charge / discharge current measured by the current sensor can be calibrated so that the offset error of the current sensor that changes each time becomes smaller.

It is a figure which shows the electric circuit for vehicles, such as an electric vehicle which consists of battery controllers which have the calibration apparatus of the current sensor of Example 1 of this invention, and peripheral devices, such as a battery and an electric motor. It is a block diagram which shows the structure of the calibration apparatus of the current sensor of Example 1. FIG. 2 is a diagram showing an internal resistance equivalent circuit model of the fuse used in the calibration device of the current sensor. It is a block diagram which shows the structure of the equivalent circuit parameter estimation part which calibrates the calibration apparatus of the current sensor of FIG. The figure which shows the result of having performed simulation about the relationship between the charging / discharging current of a battery, the both-ends voltage of a fuse, and the charging rate of the battery obtained by calibrating current with the current sensor calibration apparatus of Example 1 in time series. FIG. 4A is a diagram showing fluctuations in the charge / discharge current of the battery, FIG. 4B is a diagram showing fluctuations in the voltage across the fuse, and FIG. 4C is a diagram showing fluctuations in the charging rate. 6 is a flowchart illustrating a flow of current correction processing and current sensor failure diagnosis processing executed by the current sensor calibration apparatus according to the first embodiment. It is a block diagram which shows the structure of the equivalent circuit parameter estimation part used with the calibration apparatus of the current sensor of 2nd Example of this invention. It is a flowchart which shows the flow of the electric current correction | amendment and electric current sensor failure diagnostic processing which are performed with the calibration apparatus of the electric current sensor of 3rd Example of this invention. It is a figure which shows the characteristic of the electric current value at the time of using the current sensor of a prior art without offset correction | amendment, and a charging rate, (a) is a figure which shows the change of the electric current value containing an offset error, (b) is the electric current. It is a figure which shows the change of the charging rate obtained using this.

  Hereinafter, embodiments of the present invention will be described in detail based on examples shown in the drawings.

Hereinafter, Example 1 of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows the structural relationship between the current sensor calibration apparatus of Example 1 and the equipment to which the apparatus is connected.
In the present embodiment, the current sensor calibration device is used in vehicles such as electric vehicles and hybrid electric vehicles.

As shown in the figure, the battery 1 is constantly monitored and controlled by the battery controller 2.
The battery 1 is connected to a charger 3, a breaker 4, an inverter 5 and an electric motor 6 for charging the battery 1. When the vehicle travels, the drive power supplied to the electric motor 6 is controlled by the inverter 5. At the time of braking, the electric motor 6 functions as a generator, a part of braking energy is collected as electric energy, and the battery 2 is charged. This regeneration during braking is not always necessary.

Between the positive terminal of the battery 1 and the positive terminal of the charger 3, a relay 9 and a fuse 10 are connected in series in addition to the current sensor 7 that measures the charge / discharge current i of the battery 1. A voltage sensor 8 for measuring the terminal voltage v of the battery 1 is connected between both terminals. A relay 11 is connected between the cathode terminal of the battery 1 and the negative terminal of the charger 3.
Further, a breaker 4 and an inverter 5 are connected between the charger 3 and the electric motor 6.

The relay 9 requires a voltage sensor 12 for measuring the voltage at both ends, the fuse 10 requires a voltage sensor 13 for measuring the voltage at both ends, and the relay 11 requires a voltage sensor 16 for measuring the voltage at both ends. The voltage value measured by these is input to the battery controller 2.
Similarly, the breaker 4 is provided with a voltage sensor 14 for measuring a voltage between both terminals on the positive electrode side, and a voltage sensor 15 for measuring a voltage between both terminals on the negative electrode side, as necessary. Each measured voltage value is input to the battery controller 2.

The voltage sensors 12 to 16 are set as follows. That is, among the voltage sensors 12-16, as an essential sensor, the voltage between both ends of the internal resistance of the equivalent circuit model 17A (see FIG. 2) used in the state estimation unit 17 (see FIG. 2) of the battery controller 2 is used. Only the voltage sensor to be measured is required.
Therefore, in the present embodiment, only the fuse 10 is the target of the equivalent circuit model, so that only the voltage sensor 13 among the voltage sensors 12 to 16 is sufficient, and other voltage sensors are not necessarily required. Here, since it is possible to target other elements, the case where voltage sensors are set for all is shown for convenience.
Relays 9 and 11, fuse 10 and breaker 4 correspond to electrical elements having an internal resistance of the present invention.

The electric circuit related to the present embodiment is configured as described above, and the main components will be described in detail below.
First, the battery 1 is composed of a rechargeable battery (secondary battery). In this embodiment, a lithium ion battery pack in which a number of cells are combined is used, but the present invention is not limited to this. It goes without saying that other types of batteries such as nickel-hydrogen batteries may be used.

The current sensor 7 measures the charge / discharge current of the battery 1. In this embodiment, the current sensor 7 uses a current sensor that uses the Hall effect, which is a kind of current magnetic effect. This makes it possible to measure even if fluctuates greatly.
On the other hand, the voltage sensor 8 detects the voltage between the terminals of the battery 1 and the battery 1.

  The relays 9 and 11 and the fuse 10 constitute a junction box. The relays 9 and 11 are used for switching between supply and interruption of large electric power from the battery 1 with small electricity.

  In order to suppress the inrush current to the smoothing capacitor (not shown) of the inverter 5 when turning on the relay, sequence control is performed such that a current is temporarily supplied via a resistor and the voltage of the smoothing capacitor is sufficiently increased and then short-circuited. Do. As this resistance, in this embodiment, a fuse 10 that cuts off the circuit in the event of an abnormality is used. In this embodiment, the fuse 10 is an equivalent circuit model of FIG. 3 whose internal resistance value is R (ohms). Represented.

The charger 3 is connected to a charging facility (not shown) outside the vehicle, and charges the battery 1 by supplying power by, for example, a constant current / constant voltage charging method.
The breaker 4 ensures safety by electrically interrupting the circuit when a current exceeding an allowable amount flows from the battery 1.

  The inverter 5 is a power converter that converts the DC power from the battery 1 into three-phase AC power for driving the AC electric motor 6 by pulse width modulation (PWM) control or the like and supplies it to the electric motor 6. It is. The inverter 5 determines its output power by an inverter controller (not shown) in accordance with information such as the accelerator pedal depression amount and the vehicle speed input to the controller.

  In this embodiment, the electric motor 6 is a permanent magnet synchronous motor using a rare earth permanent magnet, and is driven by AC power from the inverter 5. The electric motor corresponds to the load of the present invention.

  The battery controller 2 is composed of an in-vehicle microcomputer, and receives various information signals from the current sensor 7 and the voltage sensors 8 and 12 to 16 for each cell of the battery 1 or the temperature of a plurality of cells. Battery management is performed by constantly monitoring voltage and current.

The battery controller 2 has the current sensor calibration device of this embodiment, and its configuration and signal flow are shown in the block diagram of FIG.
As shown in the figure, the current sensor calibration apparatus includes a state estimation unit 17, a current calculation unit 19, a current sensor / offset error calculation unit 20, and a current sensor abnormality determination unit 21.

  The state estimation unit 17 includes an internal resistance equivalent circuit model 17A of the fuse 10 and an equivalent circuit parameter estimation unit 17B as shown in FIG. The state estimation unit 17 corresponds to the state estimation unit of the present invention.

  The equivalent circuit parameter estimation unit 17B includes the internal resistance averaging processing unit 18 and the adaptation mechanism 23 of FIG. The equivalent circuit parameter estimation unit 17B and the internal resistance averaging processing unit 18 correspond to equivalent circuit parameter estimation means and internal resistance averaging processing means of the present invention, respectively.

  As shown in FIG. 4, the equivalent circuit parameter estimation unit 17 </ b> B receives the current value i (k) from the current sensor 7 to the actual fuse 10 and the internal resistance equivalent circuit model 17 </ b> A of the fuse 10. The voltage measurement value V (k) measured by the voltage sensor 13 and the estimated voltage value V (k) ^ as an output estimated by the equivalent circuit model 17A are compared by the subtractor 24, and these errors ε (k ) Is calculated. In the above symbols, the upper subscript ^ represents estimation, but is shifted to the right for convenience in the specification, unlike the drawings. Also, k is the sampling sequence number (time step), i (k) is the kth current value, V (k) is the kth voltage measurement, and V (k) ^ is the kth. Represents the estimated voltage values.

The adaptive mechanism 23 multiplies the error ε (k) by a feedback gain L (k) and feeds it back to the equivalent circuit model 17A so that the error ε (k) is minimized. Modify model 17A. By using the equivalent circuit model 17A in this way, the parameter R as the state quantity can be obtained.
Here, sequential calculation is performed using a Kalman filter, a sequential least square method, or the like, but since the internal resistance R of the fuse 10 is small, the internal resistance R is estimated with a relatively large current in order to increase the estimation accuracy. To do.

Therefore, as shown in FIG. 5 (a), these threshold values are set only when a positive current larger than the _first positive threshold value i1 and a negative current smaller than the _second negative threshold value i2 are measured. Using the positive side voltage and the negative side voltage (these are shown in FIG. 5B) of the voltage across the fuse 10 measured when the excess positive and negative currents are detected, the voltage value is expressed as a current value. By dividing, both the positive resistance value R (+) and the negative resistance value R (−) are estimated as parameters.
Here, the first threshold value i ₁ and the second threshold value i ₂ on the plus side are set to values having the same absolute value but different signs. In FIG. 5A, the true current value is indicated by a dotted line, and the current having an offset error is indicated by a solid line. In the figure, the state in which the offset error is higher than the true value is illustrated, but it is of course possible that the offset error is lower than the true value.

The internal resistance averaging processing unit 18 receives the parameters estimated by the equivalent circuit parameter estimation unit 17B, that is, the plus side resistance value R (+) and the minus side resistance value R (−), and performs the averaging process. To obtain the internal resistance R.
Here, the averaging process is performed because if the current i is offset to the plus side, the current value on the plus side is larger than its true value, so the internal resistance R (+) in that case is the voltage / Because it is current, it will be smaller than the true value. In this case, conversely, the current on the negative side decreases, and the estimated internal resistance R (−) increases. Therefore, since it is necessary to average these and cancel the offset amount, the averaging process is performed. The same applies when the current i is offset to the negative side.

The estimated resistance value R obtained by the internal resistance averaging processing unit 18 is input to the current calculation unit 19 where the fuse voltage measurement value V _FUSE measured by the voltage sensor 13 is divided by the estimated resistance value R. To obtain an estimated current value I. This estimated current value I is treated as a current calibration value (estimated value close to a true value) of the current sensor 7 from which the offset error of the current sensor 7 is removed, and is input to the current sensor / offset error calculation unit 20. The current calculation unit 19 corresponds to the current calculation unit of the present invention.

The current sensor / offset error calculation unit 20 receives the current measurement value i from the current sensor 7 and the current estimation value I obtained by the current calculation unit 19. The offset amount is I _OFFSET . This offset amount I _OFFSET is input to the current sensor abnormality determination unit 21.

The current sensor abnormality determination unit 21 determines whether or not the input offset amount I _OFFSET is normally within the range of the offset amount generated by the normal current sensor 7. If the calculated offset amount I _OFFSET is within this range, it is determined that the current sensor 7 is functioning normally, but if it is not, it is determined that the current sensor 7 is abnormal and the current sensor is abnormal. The signal of the flag FA is output so that the battery controller 2 can cope with it. The current sensor abnormality determination unit 21 corresponds to a current sensor abnormality determination unit of the present invention.

FIG. 6 is a flowchart showing the flow of current calibration and abnormality determination processing of the current sensor 7 executed by the calibration device for the current sensor 7 configured as described above.
In the figure, when an ignition key (not shown) is turned ON, the current value i, voltage value V, V _FUSE, etc. are read into the battery controller 2 from the current sensor 7 and the voltage sensors 8 and 13 in step S1. Next, as shown in step S2, when the vehicle starts to travel, the process proceeds to step S3.

In step S3, a state estimating unit 17, whether the current i read from the current sensor 7 exceeds a threshold value, i.e., a current of the positive side of the current first threshold value i ₁ larger and whether minus side first 2 threshold i ₂ is smaller than or not is determined. If this determination result is YES, the process proceeds to step S4, and if NO, the process returns to step S3.

  In step S4, it is determined whether or not the sign of the current exceeding the threshold is positive. If the determination result is YES, the process proceeds to step S5, and if the determination result is NO, the process proceeds to step S6.

In step S5, the equivalent parameter estimation unit 17B uses the plus current measurement value i (+) exceeding the first threshold i ₁ and the fuse voltage measurement value V _FUSE measured by the voltage sensor 13 to perform the equivalent. The parameter estimation of the circuit model 17A is sequentially performed, and the resistance value R (+) on the plus side is estimated. Next, the process proceeds to step S7.

Similarly, in step S6, at the equivalent parameter estimating unit 17B, the measured current value on the negative side exceeding the second threshold value i ₂ i (-) and a fuse voltage measurements V _FUSE measured by voltage sensor 13, Is used to sequentially estimate the parameters of the equivalent circuit model 17A and estimate the negative resistance value R (-). Next, the process proceeds to step S7.

  In step S7, the internal resistance averaging processing unit 18 performs an averaging process on the positive resistance value R (+) and the negative resistance value R (-) estimated as described above. The internal resistance R of the fuse 10 is calculated. Next, the process proceeds to step S8.

  In step S8, the internal resistance value calculated during the previous run and the internal resistance value calculated during the current run are averaged, and this value is used as the internal resistance value R of the fuse 10. Then, it progresses to step S9.

In step S9, the current calculation unit 19 uses the internal resistance value R calculated in step S8 and the fuse voltage measurement value V _FUSE measured by the voltage sensor 13 to calculate the current estimated value I from the relationship of current = voltage / resistance. Is calculated. This value is a current calibration value, and is close to the true value of the charge / discharge current of the battery 1 in which the offset error of the current sensor 7 is reduced. Next, the process proceeds to step S10.

In step S10, the current sensor / offset error calculation unit 20 subtracts the estimated current value I obtained by the current calculation unit 19 from the current measurement value i measured by the current sensor 7, thereby obtaining the offset amount I of the current sensor 7. Calculate _OFFSET . Whether or not the offset amount I _OFFSET calculated by the current sensor / offset error calculation unit 20 is within a predetermined range (a range of offset amounts that can be taken by a normal current sensor in advance) in the current sensor abnormality determination unit 21. Determine whether. If it is within this range, it is determined that the current sensor 7 is normal. If it is outside this range, it is determined that the current sensor 7 is abnormal, the current sensor abnormal flag FA is set, and this flag signal is output. Next, the process proceeds to step S11.

  In step S11, the calibration device for the battery 1 detects whether or not the vehicle is stopped from the vehicle speed signal obtained from the vehicle speed sensor. If the determination result is YES, the process proceeds to step S12, and if the determination result is NO, the process returns to step S3.

  In step S12, the estimated internal resistance R is recorded in the memory of the battery controller 2, and the process ends. The stored internal resistance R is used when the vehicle starts next time.

  As described above, in the calibration device for the current sensor 7 according to the first embodiment, the estimated current value I with the offset error of the current sensor 7 suppressed can be obtained, and the normality of the current sensor 7 can be obtained from this offset amount.・ Determine abnormalities.

FIG. 5 (c) shows the charge rate true value SOC _TRUE when the current measurement value of the current sensor 7 fluctuates with time as shown in FIG. 5 (a), and the charge when the offset error correction of the current sensor 7 is not performed. A simulation result comparing the rate SOC _NOOF and the charge rate SOC _COMP when the offset amount is reduced by the calibration apparatus of the present embodiment is shown. In the figure, offset correction is performed after time t1. As can be seen from the figure, the charge rate SOC _COMP obtained by calibrating the offset amount in this example is closer to the charge rate true value SOC _TRUE than the charge rate SOC _NOOF obtained by the conventional technique without offset correction. It can be seen that the estimation accuracy is high.

As described above, the current sensor calibration apparatus according to the first embodiment can obtain the following effects.
(1) In the first embodiment, an internal resistance equivalent circuit model 17A of this fuse is provided using a fuse 10 arranged in series between the battery 1 and the electric motor 6, and the internal resistance value as a state quantity is provided. Since the estimated current I is obtained by estimating R and dividing the voltage V _FUSE across the fuse 10 by this value, the offset error of the current sensor 7 can be reduced and measured by the current sensor 7. The charge / discharge current i can be calibrated.

  (2) Since the internal resistance equivalent circuit model 17 </ b> A uses the fuse 10 that was originally necessary for driving the electric motor 7, no additional member is required. Further, since the fuse 10 is modeled only by the internal resistance, modeling and calculation are simple.

(3) In the equivalent circuit parameter estimating unit 17B, among the charging and discharging current i measured by the current sensor 7, the absolute value exceeds the threshold value (second threshold value i ₂ of the first threshold value i ₁ and the negative side of the positive _side) Since the internal resistance value R is estimated by the internal resistance equivalent circuit model 17A only when the current is detected, the internal resistance value R can be obtained even when the internal resistance is small and a relatively large current flows as in the fuse 10. Can be estimated more accurately.

(4) Further, in the estimation of the internal resistance value R, the positive internal resistance value R (+) estimated by using a charge / discharge current larger than the positive first threshold value i1 and the negative side first resistance value R1. Since the negative internal resistance value R (−) estimated using the two threshold values i ₂ is obtained and averaged by the internal resistance averaging processing unit 18, the internal resistance value R is estimated. Even when the current sensor 7 has an offset error, the internal resistance value R can be estimated more accurately.

  (5) Further, the current sensor abnormality determination unit 21 calculates a difference between the current estimation value I calculated by the current calculation unit 19 and the charge / discharge current value i measured by the current sensor 7, and this difference is within a predetermined range. Since it is determined that the current sensor 7 is abnormal when it is outside, the abnormality of the current sensor 7 can be determined inexpensively and easily.

  Next, a second embodiment of the present invention will be described. In the description of the second embodiment, the same components as those of the first embodiment are not shown, or the same reference numerals are given, the description is omitted, and only the differences are described.

  The second embodiment is different from the first embodiment in that the equivalent circuit parameter estimation unit 17B of the state estimation unit 17 shown in FIG. 2 of the first embodiment is changed from that of FIG. 4 to that of FIG. That is, in the equivalent circuit parameter estimation unit 17B of the first embodiment, the parameters are estimated using the current value i (k) as the kth input and the voltage value v (k) as the kth output. On the other hand, in the equivalent circuit parameter estimation unit 17B of the second embodiment, the parameter R is estimated by sequential estimation using the input and output in combination with the k−1th previous value.

  In FIG. 7, a current value i (k) measured by the current sensor 7 is input to the fuse 10 as an input, and a voltage sensor 8 is obtained from the voltage value V (k) measured by the voltage sensor 8 as an output of the fuse 10. The previous (k−1) th voltage value v (k−1) measured in step S is subtracted by the subtractor 27 and input to the subtractor 28 as a reference signal (v (k) −v (k−1)). .

  On the other hand, the current value i (k) measured this time and the current value i (k-1) measured last time are input to the subtracter 25 by the current sensor 7, and the latter is subtracted from the former, and the fuse is Input to the internal resistance equivalent circuit model 17A.

The voltage difference estimated value difference V (k) ^-V (k-1) ^, which is the output of the internal resistance equivalent circuit model 17A, is input to the subtractor 28, and this voltage difference estimated value is calculated earlier. The error obtained by subtracting the reference signal is input to the adaptive mechanism 26, and the equivalent circuit model 17A is corrected according to the value obtained by multiplying the error by the feedback gain. The parameter R is obtained.
Others are the same as those of the first embodiment including the flowchart of FIG.

In addition to the effects (1), (2), (3), and (5) of the first embodiment, the current calibration device of the second embodiment has the following effects.
(6) In Example 2, the current value i (k) measured this time and the current value i (k-1) measured last time are input to the internal resistance equivalent circuit model 17A of the fuse 10, and Since the voltage difference estimated value difference V (k) ^-V (k-1) ^ is used as the output from the equivalent circuit model 17A, the estimation accuracy of the internal resistance value R can be increased.

  Next, a third embodiment of the present invention will be described. In the description of the third embodiment, the same components as in the first embodiment are not shown, or the same reference numerals are given, the description is omitted, and only the differences are described.

  In the current sensor calibration apparatus according to the third embodiment, the parameter estimation method in the equivalent circuit parameter estimation unit 17B of the fuse 10 is different from that in FIG. 2 of the first embodiment, and the internal resistance averaging processing unit 18 is not provided. The configuration is the same as in the first and second embodiments.

In the equivalent circuit parameter estimation unit 17B of the third embodiment, the estimation calculation of the internal resistance values R (+) and R (−) is branched by the sign of the current i as in the first and second embodiments, and the average of these is calculated. It does not take the calculation method of performing the conversion processing.
That is, in Example 3, the process shown in the flowchart of FIG. 8 is performed. In FIG. 6, steps S31 to S33 are the same as steps S1 to S3 in FIG. 6, but the subsequent steps S4 to S7 in FIG. 6 are eliminated, and step S34 is executed instead.

  In step S34, the equivalent circuit parameter estimator 17B uses the one in which the current value i exceeded the threshold value in step S3, and successively estimates the fuse voltage value measured by the voltage sensor 13 at that time. The internal resistance value R is estimated. Next, the process proceeds to step S35. Steps S35 to S39 are the same as steps S8 to S12 in FIG.

As described above, the current calibration apparatus according to the third embodiment has the following effects in addition to the effects (1), (2), (3), and (5) of the first embodiment.
(7) In the third embodiment, the equivalent circuit parameter estimation unit 17B divides the charging / discharging current i measured by the current sensor 7 into threshold values, and calculates the positive and negative internal resistance values R (+) and R (−). Since calculation and subsequent averaging are not performed, the estimation accuracy of the internal resistance value R is slightly lower than in the first and second embodiments, but the offset error of the current sensor 7 can be reduced by simple calculation. it can.

  The present invention has been described based on the above embodiments. However, the present invention is not limited to these embodiments, and is included in the present invention even when there is a design change or the like without departing from the gist of the present invention. .

For example, in each of the above embodiments, the internal resistance equivalent circuit model 17A is provided for the fuse 10 and the voltage sensor 13 for measuring the voltage V _FUSE at both ends thereof is provided. For example, the fuse 10 is disposed on the battery 1 side of the relay 9. 1 may be provided with an inverter inrush current suppression resistor that suppresses the inrush current to the inverter 5 when the relay 9 is ON, instead of the fuse 10 in this case. You may make it measure the both-ends voltage of the resistance for a certain inverter inrush current with a voltage sensor. The target of the equivalent circuit model may be any of the relays 9 and 16 and the breaker 4 in FIG. 1 instead of the fuse 10, and in this case, voltage sensors (12, 14 to 16), and an equivalent circuit model as an object is created and used. When the relays 9 and 16 and the breaker 4 are used, an equivalent model of the internal resistance R can be used as in the case of the fuse 10, and the model and calculation are simplified.

  Moreover, the current sensor calibration apparatus of the present invention may be used in an electric circuit used for a load other than the electric motor 6 or may be applied to an electric circuit other than a vehicle such as an electric vehicle.

DESCRIPTION OF SYMBOLS 1 Battery 2 Battery controller 3 Charger 4 Breaker 5 Inverter 6 Electric motor (load)
DESCRIPTION OF SYMBOLS 7 Current sensor 8 Battery voltage sensor 9,11 Relay 10 Fuse 12-16 Voltage sensor 17 State estimation part 17A Fuse internal resistance equivalent circuit model 17B Equivalent circuit parameter estimation part 18 Internal resistance averaging process part 19 Current calculation part 20 Current Sensor offset error calculation unit 21 Current sensor abnormality determination unit 23, 25 Adaptation mechanism 24, 26, 27, 28 Subtractor

Claims (6)

A current sensor for measuring the charge / discharge current value of the battery;
A voltage sensor for measuring a voltage value across an electric element arranged in series between the battery and the load;
State estimation means for inputting the charge / discharge current value measured by the current sensor and the both-end voltage measured by the voltage sensor, and estimating the internal resistance value of the electrical element based on an equivalent circuit model of the internal resistance of the electrical element; ,
Current calculating means for calculating a current estimated value from the internal resistance value estimated by the state estimating means and the both-ends voltage value detected by the voltage sensor to be a current calibration value of the current sensor;
A calibration device for a current sensor, comprising: The calibration device for a current sensor according to claim 1,
The electrical element is one of a fuse, a relay, a breaker, and an inverter inrush current suppression resistor.
A calibration device for a current sensor. In the current sensor calibration device according to claim 1 or 2,
The state estimation means includes equivalent circuit parameter estimation means for estimating the internal resistance value using only a charge / discharge current value whose absolute value is larger than a predetermined threshold among charge / discharge current values detected by the current sensor.
A calibration device for a current sensor. The current sensor calibration device according to claim 3,
In the equivalent circuit parameter estimation unit, the state estimation unit has a positive first threshold value and a negative second threshold value as the threshold value, and a positive charging current value larger than the first threshold value and the first threshold value. Estimate the internal resistance value on the positive side and the internal resistance value on the negative side from the negative discharge current value smaller than 2 threshold values,
An internal resistance averaging processing means for averaging the positive internal resistance value and the negative internal resistance value to estimate the internal resistance value;
A calibration device for a current sensor. The current sensor calibration device according to any one of claims 1 to 4,
The charge / discharge current values sampled over the preceding and following times are used for the input to the equivalent circuit model of the internal resistance, and the both-end voltage values sampled for the preceding and following times are used for the output of the electrical element,
A calibration device for a current sensor. The current sensor calibration device according to any one of claims 1 to 5,
A current that calculates a difference between an estimated current value calculated by the current calculation means and a charge / discharge current value measured by the current sensor, and determines that the current sensor is abnormal when the difference is outside a predetermined range. Provided sensor abnormality determination means,
A calibration device for a current sensor.

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