JP6717166B2 - Current detector - Google Patents

Description

The present disclosure relates to a technique of detecting each phase current to a motor that is driven by being supplied with a three-phase current.

2. Description of the Related Art Various vehicles, such as electric vehicles and hybrid vehicles, equipped with a motor driven by a three-phase current (hereinafter referred to as a three-phase motor) have become widespread as a driving source for traveling. This type of vehicle is usually equipped with an inverter that generates U, V, and W phase currents, and the three-phase motor is driven by supplying the three-phase current from the inverter to the three-phase motor.

As a method of controlling each phase current from the inverter to the three-phase motor, a method of individually detecting the current of each phase and controlling each phase current based on each detected value is widely known. In this control method, a current sensor is provided for each phase current supply path, and control is performed based on each current value detected by each current sensor.

In recent years, with the increase in output of three-phase motors, the value of each phase current supplied from the inverter to the three-phase motor has also tended to increase. When the current of each phase becomes large, it becomes necessary to mount a current sensor having a large rating accordingly. However, if a current sensor with a large rating is newly selected, there is a concern that the cost will increase due to the cost of selection and the cost of the current sensor itself.

On the other hand, in Patent Document 1, a bus bar in which a current to be detected flows is branched into a plurality of parts, a current sensor is provided in one of the plurality of branch bars, and the current flows to the entire bus bar from the detection result of the one current sensor. Techniques for detecting current are described.

JP, 2002-257866, A

If the method described in Patent Document 1 is used as the method of detecting each phase current to the three-phase motor, even if the phase current is large, it is not necessary to directly detect the entire phase current, and a branched portion is used. It is sufficient to detect the current of. Therefore, it is not necessary to increase the rating of the current sensor according to the size of the entire phase current.

However, since the currents of all of the plurality of branch paths are not directly detected, the entire phase current may not be detected accurately. On the other hand, if the current sensors are provided on all of the plurality of branch paths and the detection values of the respective current sensors are summed up, the detection accuracy of the entire phase current can be improved.

However, if the current sensors are provided in all the branch paths, the total number of the current sensors naturally increases, and there is a concern that the failure probability of the current sensors as a whole increases accordingly. Further, when any of the current sensors of the same phase fails, it is difficult to identify which of the current sensors has failed.

The present disclosure relates to a motor drive device configured to supply each phase current to a three-phase motor by branching into a plurality of phases for each phase, and providing a current sensor in each of the plurality of branch paths. Provided is a technique that enables a failed current sensor to be detected quickly and accurately in the event of a failure.

One aspect of the present disclosure is a current detection device (13) used in a motor drive device (1). The motor drive device supplies a predetermined current to each of the current supply paths (21, 22, 23) for each phase from the drive circuit (12) that supplies a three-phase current to the motor (10) to the motor. A plurality of branch paths (21a, 21b, 22a, 22b, 23a, 23b) configured to branch into a plurality of branches at a branching ratio and join again are provided. Further, each phase is provided with a current sensor (UA, UB, VA, VB, WA, WB) for detecting a current flowing through the branch path of the phase.

The current detection device of the present disclosure used in the motor drive device having such a configuration, for each phase, of the detected current value that is the value of the current detected by each current sensor provided in the plurality of branch paths of the phase The sum is detected as the current value of the phase.

Then, the current detection device of the present disclosure includes a normality determination unit (13, S210, S220), a three-phase total sum calculation unit (13, S240), and a failure determination unit (13, S250, S310).

The normality determination unit determines, for each phase, a plurality of branches of the phase based on the ratio of the detected current values by the current sensors provided in the plurality of branch paths of the phase and the ratio of the branch ratio of the phase. It is determined whether all the current sensors provided on the path are normal.

When the normality determining unit determines that all of the phases are not normal, the three-phase total sum calculating unit determines that one abnormal current sensor is included in other words. In this case, for each current sensor in the abnormal phase that is the determined phase, the detected current value of the current sensor is divided by the branching ratio of the branch path in which the current sensor is provided. And the sum of the detected current values of the current sensors in the other two phases other than the abnormal phase, the three-phase total value is calculated.

When the three-phase sum total value calculated by the three-phase sum total calculation unit does not satisfy the specific normal condition, the failure determination unit detects the abnormal phase-deemed current value included in the three-phase total sum value. The failure of the current sensor that detected the current value is determined.

In the current detection device having such a configuration, when it is determined that any one of the phases is an abnormal phase, it is determined for each current sensor in the abnormal phase whether or not the current sensor is out of order. Specifically, the current value regarded as the abnormal phase is calculated by using the detected current value of one of the current sensors in the abnormal phase. This abnormal phase deemed current value is a value obtained by dividing the actual detected current value by the branching ratio, so if the actual detected current value is a normal value, it will match or almost match the actual current value of the abnormal phase. Will be equivalent.

Then, the three-phase sum total value is calculated using the abnormal phase regarded current value. Here, the sum of the three-phase currents is theoretically 0, as is well known. That is, no matter which timing the current values of the three phases that change in time series are added, theoretically it becomes zero.

By appropriately setting the normal condition in consideration of the theoretical characteristics of the three-phase current, it is possible to appropriately determine whether or not the current sensor has a failure based on the three-phase sum value. For example, the normal condition may be that the three-phase sum value is at or near zero.

Therefore, according to the current detection device of the present disclosure configured as described above, when any of the current sensors fails, the failed current sensor can be detected quickly and accurately.
It should be noted that the reference numerals in parentheses described in this column and the claims indicate the correspondence with the specific means described in the embodiments to be described later as one aspect, and the technical scope of the present disclosure. It is not limited.

It is explanatory drawing which shows schematic structure of the motor drive device of embodiment. It is explanatory drawing which shows an example of the sensor value of each phase detected when the U-phase 2nd electric current sensor is out of order. It is explanatory drawing for chronologically explaining various processes performed when a U-phase second current sensor fails. It is a flow chart of current sensor monitoring processing of an embodiment. 5 is a flowchart of a failure determination process of S120 in the current sensor monitoring process of FIG. 5 is a flowchart of the waveform information acquisition process of S140 in the current sensor monitoring process of FIG. 5 is a flowchart of a restoration/discard determination process of S160 in the current sensor monitoring process of FIG. It is a flow chart of phase current calculation processing of an embodiment.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.
[1. Embodiment]
(1-1) Configuration of Motor Drive Device The motor drive device 1 shown in FIG. 1 includes a motor 10, a battery 11, an inverter 12, and a control device 13. The motor drive device 1 of the present embodiment is mounted in, for example, a vehicle. The motor 10 is configured to rotate the drive wheels of the vehicle as a driving source for driving the vehicle.

The battery 11 is a power source for driving the motor 10. The battery 11 has a rechargeable secondary battery such as a nickel hydrogen battery or a lithium ion battery, and DC power is output from the secondary battery.

The inverter 12 converts the DC power supplied from the battery 11 into three-phase AC power of U phase, V phase, and W phase, and supplies the AC power to the motor 10. Inverter 12 supplies motor 10 with sinusoidal three-phase alternating currents having phases different from each other by 120 degrees, that is, three-phase currents of U-phase current Iu, V-phase current Iv, and W-phase current Iw. The inverter 12 of the present embodiment is equipped with, for example, an IGBT as a power conversion element.

The motor 10 is driven by the three-phase current supplied from the inverter 12. The motor 10 of this embodiment is, for example, a synchronous motor having a permanent magnet as a field.
The inverter 12 and the motor 10 are connected by a U-phase bus bar 21, a V-phase bus bar 22 and a W-phase bus bar 23 for supplying a three-phase current from the inverter 12 to the motor 10.

The U-phase current Iu output from the inverter 12 is supplied to the motor 10 by the U-phase bus bar 21 and input to the U-phase current input terminal of the motor 10. The V-phase current Iv output from the inverter 12 is supplied to the motor 10 by the V-phase bus bar 22 and input to the V-phase current input terminal of the motor 10. The W-phase current Iw output from the inverter 12 is supplied to the motor 10 by the W-phase bus bar 23 and input to the W-phase current input terminal of the motor 10.

In the U-phase bus bar 21, a part of the entire path from the inverter 12 to the motor 10 is branched by two branch bars 21a and 21b. That is, the U-phase current Iu output from the inverter 12 branches into two paths of the U-phase first branch bar 21 a and the U-phase second branch bar 21 b in the middle of the U-phase bus bar 21. Then, the branched currents merge again and are input to the motor 10 via the U-phase bus bar 21.

The branch ratio of the U-phase current Iu branched to each of the U-phase first branch bar 21a and the U-phase second branch bar 21b is 50%. That is, the U-phase current Iu is bisected by the two branch bars 21a and 21b at a branching ratio of 1:1.

Further, each of the U-phase first branch bar 21a and the U-phase second branch bar 21b is provided with a current sensor for detecting the value of the current flowing through the branch bar. Specifically, the U-phase first branch bar 21a is provided with a U-phase first current sensor UA, and the U-phase second branch bar 21b is provided with a U-phase second current sensor UB.

The V-phase bus bar 22 and the W-phase bus bar 23 also have basically the same configuration as the U-phase bus bar 21. That is, in the V-phase bus bar 22, a part of the entire path from the inverter 12 to the motor 10 is branched by the two branch bars 22a and 22b. The V-phase current Iv output from the inverter 12 branches into two paths of the V-phase first branch bar 22 a and the V-phase second branch bar 22 b in the middle of the V-phase bus bar 22. Then, the branched currents merge again and are input to the motor 10 via the V-phase bus bar 22.

In the present embodiment, the branch ratio of the V-phase current Iv branched to each of the V-phase first branch bar 22a and the V-phase second branch bar 22b is 50%, like the U-phase current branch ratio. That is, the V-phase current Iv is also bisected by the two branch bars 22a and 22b at a branching ratio of 1:1 like the U-phase current Iu.

Further, the V-phase first branch bar 22a and the V-phase second branch bar 22b are each provided with a current sensor for detecting the value of the current flowing through the branch bar. Specifically, the V-phase first branch bar 22a is provided with a V-phase first current sensor VA, and the V-phase second branch bar 22b is provided with a V-phase second current sensor VB.

Also in the W-phase bus bar 23, a part of the entire path from the inverter 12 to the motor 10 is branched by the two branch bars 23a and 23b. The W-phase current Iw output from the inverter 12 branches into two paths of the W-phase first branch bar 23 a and the W-phase second branch bar 23 b in the middle of the W-phase bus bar 23. Then, the branched currents merge again and are input to the motor 10 via the W-phase bus bar 23.

In the present embodiment, the branching ratio of the W-phase current Iw that branches into each of the W-phase first branch bar 23a and the W-phase second branch bar 23b is 50%, like the U-phase current branching ratio. That is, like the U-phase current Iu and the V-phase current Iv, the W-phase current Iw is equally bisected by the two branch bars 23a and 23b at a branching ratio of 1:1.

Further, the W-phase first branch bar 23a and the W-phase second branch bar 23b are each provided with a current sensor for detecting the value of the current flowing through the branch bar. Specifically, the W-phase first branch bar 23a is provided with a W-phase first current sensor WA, and the W-phase second branch bar 23b is provided with a W-phase second current sensor WB.

In the present embodiment, each of the current sensors UA, UB, VA, VB, WA, WB is a so-called through-type current sensor, has a ring-shaped detection core, and branches the branch bar to be detected with respect to the branch bar. The bar is arranged so as to penetrate the detection core. Then, the detection signal corresponding to the value of the current flowing through the branch bar to be detected is output. Various types of current sensors on the penetrating side are well known, including those having a Hall element as described in Patent Document 1, for example. The description is omitted. The detection signals output from the current sensors UA, UB, VA, VB, WA, WB are input to the control device 13.

The control device 13 is mainly composed of a well-known microcomputer having a CPU 13a and a memory 13b. The memory 13b has a semiconductor memory such as a RAM, a ROM, or a flash memory. Various functions of the control device 13 are realized by the CPU 13a executing a program stored in the non-transitional physical recording medium. In this example, the memory 13b corresponds to a non-transitional substantive recording medium storing a program. By executing this program, the method corresponding to the program is executed. It should be noted that the number of microcomputers forming the control device 13 may be one or more.

The programs stored in the memory 13b include a current sensor monitoring process program of FIGS. 4 to 7 described later and a phase current calculation process program of FIG. 8 described later. Some or all of the various functions realized by the execution of the program in the control device 13 may be realized by using one or a plurality of hardware.

The control device 13 detects the value of the current flowing through the U-phase first branch bar 21a based on the detection signal from the U-phase first current sensor UA, and U based on the detection signal from the U-phase second current sensor UB. The value of the current flowing through the phase second branch bar 21b is detected. The current value detected based on the detection signal from the U-phase first current sensor UA is referred to as the U-phase first sensor value IuA, and the current value detected based on the detection signal from the U-phase second current sensor UB is It is referred to as the U-phase second sensor value IuB. The control device detects the sum of the detected U-phase first sensor value IuA and U-phase second sensor value IuB as the U-phase current value Iu.

Further, the control device 13 detects the value of the current flowing through the V-phase first branch bar 22a based on the detection signal from the V-phase first current sensor VA, and based on the detection signal from the V-phase second current sensor VB. The value of the current flowing through the V-phase second branch bar 22b is detected. The current value detected based on the detection signal from the V-phase first current sensor VA is referred to as the V-phase first sensor value IvA, and the current value detected based on the detection signal from the V-phase second current sensor VB is It is referred to as a V-phase second sensor value IvB. The control device 13 detects the total sum of the detected V-phase first sensor value IvA and V-phase second sensor value IvB as the V-phase current value Iv.

Further, the control device 13 detects the value of the current flowing through the W-phase first branch bar 23a based on the detection signal from the W-phase first current sensor WA, and based on the detection signal from the W-phase second current sensor WB. The value of the current flowing through the W-phase second branch bar 23b is detected. The current value detected based on the detection signal from the W-phase first current sensor WA is referred to as the W-phase first sensor value IwA, and the current value detected based on the detection signal from the W-phase second current sensor WB is It is referred to as the W-phase second sensor value IwB. The control device 13 detects the sum of the detected W-phase first sensor value IwA and the detected W-phase second sensor value IwB as the W-phase current value Iw.

The control device 13 controls the drive of the motor 10 by controlling the output of the three-phase current by the inverter 12 based on various information including the detected phase current values Iu, Iv, and Iw.

Further, the control device 13 monitors whether or not the current sensors UA, UB, VA, VB, WA, WB are normal based on the sensor values IuA, IuB, IvA, IvB, IwA, IwB.

(1-2) Operation of the control device when the current sensor fails The specific contents of the monitoring of each current sensor by the control device 13 and the outline of the operation when a failure of any current sensor is detected will be described with reference to FIG. This will be described with reference to FIG.

The control device 13 of the present embodiment has a failure when any one of the six current sensors UA, UB, VA, VB, WA, WB fails and a normal detection signal is not output. One current sensor can be specified.

In this embodiment, each phase current supplied from the inverter 12 to the motor 10 is divided into two equal parts in the middle of the bus bar. Therefore, if all the current sensors are normal, the two sensor values detected by the control device 13 for each phase are the same.

On the other hand, for example, it is assumed that the U-phase second current sensor UB out of the current sensors UA and UB provided in the U-phase branch bars 21a and 21b fails. In this case, the U-phase first sensor value IuA and the U-phase second sensor value IuB may not match.

FIG. 2 shows an example of each sensor value when the U-phase second current sensor UB out of the six current sensors fails and all the other five current sensors are normal. As shown in FIG. 2, if the two current sensors in each phase are normal, the two sensor values will be the same value, but if one of the two current sensors fails, the two sensor values will be different values. Become.

From this, it is possible to determine whether the two current sensors are normal or whether at least one of them is defective depending on whether the sensor values of the two current sensors are the same in each phase. More generally speaking, the ratio of the sensor values of the two current sensors in each phase is the ratio of the branch ratios in each branch bar provided with the two current sensors (hereinafter, also referred to as “normal ratio”). It is possible to determine whether both of the two current sensors are normal depending on whether the two current sensors match.

Therefore, the control device 13 monitors, for each phase, the two sensor values of the phase and, based on the ratio of both and the normal ratio, monitors whether both of the two current sensors are normal. Then, in a certain phase of the three phases, when both of the two current sensors are not normal, the faulty current sensor is identified, and the sensor value of the faulty current sensor is corrected.

Here, the operation of the control device 13 when the U-phase second current sensor UB fails will be described with reference to FIG. FIG. 3 shows an example of changes in the U-phase sensor values IuA and IuB. FIG. 3 shows that the U-phase first current sensor UA is normal and the U-phase first sensor value IuA is normal, while the U-phase second current sensor UB has a failure at time t1 and is time t1. Hereinafter, examples in which the U-phase second sensor value IuB is no longer a normal value are shown. In FIG. 3, time t0, time t3, and time t7 are all timings when the U-phase first sensor value IuA becomes zero cross.

As illustrated in FIG. 3, until immediately before time t1, the two current sensors UA and UB are both normal, so that the sensor values IuA and IuB of both sensors are substantially the same. On the other hand, when the U-phase second current sensor UB fails at time t1 and the value of the U-phase second sensor value IuB becomes lower than the actual value and is detected, the respective sensor values IuA and IuB are detected. The difference becomes large. In other words, the ratio of the sensor values IuA and IuB is different from the normal ratio.

The control device 13 periodically performs a failure determination process including a determination as to whether the ratio of the sensor values IuA and IuB matches the normal ratio. In the present embodiment, since the normal ratio is 1:1, it is actually determined whether or not the sensor values IuA and IuB match with each other in determining whether the ratio of the sensor values IuA and IuB matches the normal ratio. It is done by judging. That is, in the present embodiment, that the sensor values IuA and IuB match and that the ratio of the sensor values IuA and IuB match the normal ratio are synonymous.

It should be noted that, here, that the sensor values match does not mean that the sensor values are literally exactly the same. For example, if the difference between the two is within a certain value, it is considered that they match. Good. The matching between the ratio of the sensor values IuA and IuB and the normal ratio does not mean that they are completely matched literally, but includes the case where they are within the range where they can be considered to be matched. For example, assuming that the normal ratio is x0:y0 and the ratio of the actual sensor values is x:y, if x/y is within a predetermined range including x0/y0, they may be considered to match. Good.

At time t1, when the U phase becomes an abnormal phase in which the sensor values IuA and IuB do not match, the control device 13 targets the U phase, which is the abnormal phase, and which of the sensor values IuA and IuB is incorrect? That is, it is determined which of the current sensors UA and UB is out of order.

Specifically, the three-phase total sum value described below is calculated individually for each of the U-phase current sensors UA and UB, and the presence or absence of a failure is determined based on the three-phase total sum value. That is, for example, first, for the U-phase first current sensor UA, the U-phase first sensor value IuA is divided by the branch ratio of the U-phase first branch bar 21a provided with the U-phase first current sensor UA. The result of this division is regarded as the U phase current value. This U-phase deemed current value should match the actual value of the U-phase current Iu if the U-phase first sensor value IuA is a normal value. In the present embodiment, since the branching ratio is 50% as described above, the U-phase deemed current value may be calculated by simply doubling the U-phase first sensor value IuA.

When the U-phase deemed current value is calculated using the U-phase first sensor value IuA, it is the sum of the U-phase deemed current value and the V-phase and W-phase sensor current values IvA, IvB, IwA, IwB, Calculate the three-phase sum value. Then, it is determined whether the three-phase sum value satisfies the normal condition. As described above, the total sum of the three-phase currents is theoretically zero. Therefore, in this embodiment, it is set that the three-phase sum value is 0 as a normal condition. Note that the three-phase sum value 0 here does not mean that the three-phase sum value is literally completely 0, and for example, from a negative predetermined value smaller than 0 to a positive predetermined value larger than 0. , 0 may be considered to be within a predetermined range including 0. The maximum difference between the three-phase total value and 0 may be appropriately determined as to how the three-phase total value is regarded as 0.

If the three-phase total value calculated using the U-phase deemed current value based on the U-phase first sensor value IuA satisfies the normal condition, that is, if the three-phase total value is 0, the U-phase first current sensor UA Judge as normal.

Then, as a target of the U-phase second sensor UB, a failure determination based on the three-phase total sum value is performed as described above. That is, the U-phase second sensor value IuB is divided by the branch ratio of the U-phase second branch bar 21b provided with the U-phase second current sensor UB, and the division result is regarded as the U-phase regarded current value. In the present embodiment, the U-phase second branch bar 21b has a branching ratio of 50% as described above. Therefore, the U-phase deemed current value should simply double the U-phase second sensor value IuB. It may be calculated by

When the U-phase deemed current value is calculated using the U-phase second sensor value IuB, it is the sum of the U-phase deemed current value and the V-phase and W-phase sensor current values IvA, IvB, IwA, and IwB. Calculate the three-phase sum value. Then, it is determined whether the three-phase sum value satisfies the normal condition. In the case of the example of FIG. 3, since the U-phase second sensor value IuB is no longer a normal value, the three-phase total value calculated using the U-phase deemed current value based on the U-phase second sensor value IuB is a normal condition. Does not meet. That is, the three-phase sum value does not become zero.

Therefore, the control device 13 makes a provisional determination that the U-phase second current sensor UB is out of order, and sets the state of the U-phase second current sensor UB to "during failure determination". Then, subsequently, a failure determination process for the U phase, which includes the presence/absence of a failure based on the above-described three-phase sum value, is periodically performed. Then, it is continuously determined that the three-phase total value based on the U-phase second sensor value IuB does not satisfy the normal condition, and when the cumulative number becomes equal to or more than the failure determination threshold value at time t4, the U-phase second current. The formal determination that the sensor UB is out of order is made, and the state of the U-phase second current sensor UB is set to "failure".

The controller 13 periodically calculates the phase current values Iu, Iv, and Iw by a phase current calculation process described later, and uses the calculated phase current values Iu, Iv, and Iw in various controls. .. For example, the U-phase current value Iu is calculated by adding the U-phase first sensor value IuA and the U-phase second sensor value IuB if both the U-phase current sensors UA and UB are normal.

At time t1, a tentative determination is made that the U-phase second current sensor UB has failed, but the U-phase current value Iu continues to be the U-phase first sensor value IuA until it is officially determined to be failed. And the U-phase second sensor value IuB are added.

When the failure of the U-phase second current sensor UB is officially determined at time t4, the control device 13 calculates the U-phase current value IuB by interpolation calculation using the U-phase first sensor value UA. To do. That is, the U-phase second sensor value IuB is invalidated and the use of the U-phase second sensor value IuB for the calculation of the U-phase current value IuB is stopped. Then, the U-phase current value IuB is calculated by interpolation calculation based on the U-phase first sensor value IuA and the branch ratio of the U-phase first branch bar 21a. The interpolation calculation is specifically the same as the calculation of the U-phase deemed current value described above. That is, the interpolation calculation means to calculate the deemed current value using the other sensor value that is not determined to be a failure. The control device 13 calculates the U-phase deemed current value using the U-phase first sensor value IuA, and uses it as the U-phase current value Iu for various controls.

When the control device 13 makes a provisional determination of the failure of the U-phase second current sensor UB at time t1, in addition to continuously executing the failure determination process, it newly newly executes the waveform information acquisition process. The waveform information acquisition process is a preliminary process for correcting the U-phase second sensor value IuB that is no longer a normal value and making it usable. The periodical execution of the failure determination process is continued until the failure of the U-phase second current sensor UB is officially determined at time t4.

Specifically, the control device 13 uses the U-phase first sensor value IuA detected by the U-phase first current sensor UA as the normal current sensor and the U-phase second sensor UB as the fault current sensor after the time t1. Each of the detected U-phase second sensor values IuB detects a plus peak, which is the maximum value, and a minus peak, which is the minimum value, in the process of periodically increasing and decreasing.

In the example of FIG. 3, after time t1, first, at time t2, the positive peak IppA of the U-phase first sensor value IuA and the positive peak IppB of the U-phase second sensor value IuB are detected. After that, at time t5, the minus peak IpnA of the U-phase first sensor value IuA and the minus peak IpnB of the U-phase second sensor value IuB are detected.

The control device 13 calculates the offset error Doff and the gain error Gd used to correct the U-phase second sensor value IuB when the positive and negative maximum and minimum values are detected at time t5.

The offset error Doff is calculated as follows. That is, the amplitude center value PB0 of the U-phase second sensor value IuB is calculated based on the plus peak IppB and the minus peak IpnB of the U-phase second sensor value IuB as the failure detection current value. Then, a value obtained by inverting the sign of the amplitude center value PB0 is calculated as an offset error Doff. For example, when the amplitude center value PB0 is −20 [A], the offset error Doff is calculated as 20.

The offset error Doff may be calculated more accurately by using the plus peak IppA and minus peak IpnA of the U-phase first sensor value IuA as the normal detection current value. For example, the amplitude center value is calculated based on at least one of the positive peak IppA and the negative peak IpnA of the U-phase first sensor value IuA, and the calculated amplitude center value and the amplitude center value PB0 of the U-phase second sensor value IuB. The difference between and may be calculated as an offset error Doff.

The gain error Gd is calculated as follows. That is, the amplitude of the U-phase second sensor value IuB is obtained based on the plus peak IppB and the minus peak IpnB of the U-phase second sensor value IuB. For example, the amplitude of the U-phase second sensor value IuB can be obtained by obtaining the peak-peak value of the U-phase second sensor value IuB and dividing the peak value into two.

Further, the amplitude of the U-phase first sensor value IuA is obtained based on at least one of the positive peak IppA and the negative peak IpnA of the U-phase first sensor value IuA. For example, either one of the absolute values of the plus peak IppA and the minus peak IpnA may be used as the amplitude of the U-phase first sensor value IuA, or the peak-peak value of the U-phase first sensor value IuA is obtained and divided into two. You may obtain|require amplitude by doing.

Then, the ratio of the amplitude of the U-phase first sensor value IuA to the amplitude of the U-phase second sensor value IuB is calculated, and the calculation result is set as the gain error Gd. For example, when the amplitude of the U-phase second sensor value IuB is K1 and the amplitude of the U-phase first sensor value IuA is K2, the gain error Gd is calculated by K2/K1.

In FIG. 3, time t6 is the timing when the offset error Doff and the gain error Gd are calculated and the preparation for correction is completed.
In this way, when the offset error Doff and the gain error Gd are obtained at time t6, the state of the U-phase second current sensor UB is set to “restoration determination in progress”. Then, thereafter, every time the U-phase second sensor value IuB is detected, a correction calculation is performed on the U-phase second sensor value IuB. The correction calculation is stopped when the state of the U-phase second current sensor UB returns to "normal" or "discard".

Specifically, the correction calculation is performed by the following equation (1). In the formula (1) below, IuBc represents a U-phase second failure correction value which is a failure correction value of the U-phase second sensor value IuB.
IuBc=(IuB+Doff)*Gd (1)
When the state of the U-phase second current sensor UB is set to "during restoration determination" at time t6, the control device 13 periodically executes restoration/discard determination processing instead of the waveform information acquisition processing. The restoration/discard determination processing determines whether the U-phase second failure correction value obtained by the correction calculation is an appropriate value, in other words, whether the calculated offset error Doff and gain error Gd are appropriate values. This is a process for doing.

The restoration/discard determination processing is performed based on whether or not the ratio between the U-phase first sensor value IuA and the U-phase second failure correction value IuBc matches the corresponding branch ratio ratio. In the present embodiment, since the normal ratio is 1:1, it is actually determined whether or not the U-phase first sensor value IuA and the U-phase second failure correction value IuBc match, more specifically, both. Based on whether or not the difference is less than or equal to the threshold.

Then, in the recovery/discard determination processing that is periodically performed, when it is continuously determined that the difference between the two is less than or equal to the threshold value for the recovery threshold value, the U-phase second failure correction value IuBc obtained by the correction calculation is appropriate. The value of the U-phase second current sensor UB is set to “restored”. In the example of FIG. 3, it is set to “recovery” at time t8.

When "recovery" is set at time t8, the periodical execution of the recovery/discard determination processing is stopped. Then, thereafter, the failure determination process is periodically executed again. In the failure determination process executed in the “recovery” state, it is monitored whether the ratio between the U-phase first sensor value IuA and the U-phase second failure correction value IuBc matches the normal ratio.

When set to "recovery" at time t8, the control device 13 uses the U-phase second failure correction value IuBc obtained by the correction calculation as the value of the current flowing through the U-phase second branch bar 21b. That is, for the U-phase current value Iu, the control device 13 calculates the sum of the U-phase first sensor value IuA and the U-phase second failure correction value IuBc, and uses this as the U-phase current value Iu for various processes. .. In the restoration/discard determination processing, if the U-phase second failure correction value IuBc obtained by the correction calculation is not determined to be an appropriate value, the U-phase current value Iu continues to be the U-phase first value. The U-phase deemed current value using the sensor value IuA is used.

(1-3) Current Sensor Monitoring Process Next, the current sensor monitoring process executed by the control device 13 to realize the operation illustrated in FIG. 3 will be described with reference to FIG. After activation, the control device 13 repeatedly executes the current sensor monitoring process of FIG. 4 in a predetermined control cycle during a predetermined monitoring period in which each current sensor should be monitored. The current sensor monitoring process is actually executed in the control device 13 by the above-described CPU according to the current sensor monitoring process program stored in the memory.

The current sensor monitoring process is individually executed for each phase of U, V, and W. That is, the current sensor monitoring process executed with each of the U-phase current sensors UA and UB as a monitoring target, the current sensor monitoring process executed with each of the V-phase current sensors VA and VB as a monitoring target, and each of the W-phase The current sensor monitoring process executed with the current sensors WA and WB as the monitoring targets is executed in parallel as, for example, a multitask.

When the control device 13 starts the current sensor monitoring process of FIG. 4, in S110, the state of the first current sensor is “normal”, “recovery”, or “during failure determination”, and the second current sensor It is determined whether the state is also “normal”, “recovery”, or “during failure determination”. In addition, in the description after FIG. 4, the “first current sensor” and the “second current sensor” mean two current sensors corresponding to the phase to be processed. For example, when the processing target is the U phase, it means the U phase first current sensor UA and the U phase second current sensor UB.

If an affirmative decision is made in S110, the operation proceeds to S120, and if a negative decision is made in S110, the operation proceeds to S130.
In S120, a failure determination process is executed. The details of the failure determination process are as shown in FIG. When proceeding to the failure determination process, the control device 13 acquires each sensor value of the relevant phase at the present time and calculates a ratio of each sensor value in S210. For example, when the processing target is the U phase, the ratio between the U phase first sensor value IuA and the U phase second sensor value IuB is calculated. When there is a current sensor whose state is “recovery” out of the two current sensors, the failure correction value is used for the current sensor instead of the sensor value itself.

In S220, based on the ratio calculated in S210, it is determined whether or not each sensor value is normal. Specifically, it is determined whether the calculated ratio matches the normal ratio. In this embodiment, the normal ratio is 1:1. Therefore, in S210 to S220, it is determined whether or not the sensor values actually match.

If both sensor values are normal in S220, the failure determination process is terminated, and the process proceeds to S130 in FIG. The case where both sensor values are normal is the case where the calculated ratio matches the normal ratio, and the case where the normal ratio is 1:1 is the case where the sensor values match.

If both sensor values are not normal, that is, if at least one of them is defective, the process proceeds to S230. In S230, the variable X is set to the number of the next current sensor. When the process of S230 is performed for the first time after the current sensor monitoring process is started, the variable X is set to the initial value “1”.

In S240, the apparent current value of the phase is calculated using the Xth sensor value of the phase. Then, the deemed current value is used to calculate the three-phase sum value. For example, when the processing target is the U-phase, the U-phase X-sensor value is used to calculate the U-phase considered current value, and the U-phase considered current value and each of the V-phase and W-phase sensor current values IvA, IvB, IwA. , IwB is calculated as a three-phase total sum value.

In S250, it is determined whether or not the three-phase sum value calculated in S240 is normal, that is, whether or not the above-described normal condition is satisfied. If the three-phase sum value satisfies the normal condition, the process proceeds to S280. In S280, the counter value of the failure counter (hereinafter, failure counter value) is cleared to 0. In S290, the state of the Xth current sensor is set to "normal". However, if it is already set to "Recovery", the setting of "Recovery" is maintained. After the processing of S290, the process proceeds to S300.

If the three-phase total value does not satisfy the normal condition in S250, the process proceeds to S260. In S260, the failure counter value is incremented by 1 from the current value. In S270, the state of the Xth current sensor is set to "during failure determination".

In S300, it is determined whether the failure counter value is greater than or equal to the failure determination threshold value. The failure determination threshold value may be appropriately determined, and is “12” in this embodiment. If the failure counter value is less than the failure determination threshold value, the process proceeds to S320. If the failure counter value is greater than or equal to the failure determination threshold value, the process proceeds to S310. In S310, the state of the Xth current sensor is set to "failure".

In S320, it is determined whether or not the determination has been performed for all the current sensors of the phase, that is, whether or not the processing of S240 and the following has been performed on the sensor values of all the current sensors of the phase. When all the current sensors of the phase have been determined, the process proceeds to S130 of FIG. If there is a current sensor that has not been determined yet, the process returns to S230.

For example, when the determination has been performed only up to the first current sensor, the process returns to S230. In this case, in S230, the variable X is set from the current "1" to "2" indicating the next current sensor, which allows the second current sensor to be processed in S240 below. Done.

In S130 of FIG. 4, whether one of the states of the first current sensor and the second current sensor is “during failure determination” or “fault”, and the other state is “normal” or “recovery”. To judge. If an affirmative decision is made in S130, the operation proceeds to S140.

In S140, waveform information acquisition processing is executed. The details of the waveform information acquisition processing are as shown in FIG. When proceeding to the waveform information acquisition process, the control device 13 performs a peak acquisition process in S410.

This peak acquisition process is a process of acquiring the above-mentioned plus peak and minus peak for each sensor value of the phase. The control device 13 acquires each sensor value of the relevant phase at the present time, and determines whether each is the maximum value or the minimum value. If there is a current sensor whose status is "recovery" out of the two current sensors, the current sensor is either the maximum value or the minimum value, not the sensor value itself, but the failure correction value. Judge whether there is.

Then, if there is a maximum sensor value, that sensor value is obtained as a plus peak of the current sensor, and if there is a minimum sensor value, that sensor value is obtained. Get as a negative peak. The acquired plus peak or minus peak is temporarily stored in the memory 13b.

In S420, it is determined whether or not both the positive peak and the negative peak have been acquired for both the first sensor value of the first current sensor and the second sensor value of the second current sensor, that is, they are stored in the memory 13b. Determine if both are in a saved state. If there is a peak that has not been acquired yet, the current sensor monitoring process ends. When all the plus peaks and minus peaks to be acquired are in the acquired state, the process proceeds to S430.

In S430, the offset error is calculated by the same method as the method of calculating the offset error Doff described above with reference to FIG. That is, the offset error is calculated by the above-mentioned method from the plus and minus peaks of the sensor value of the current sensor set to "during failure determination" or "failure" as the failure detection current value. ..

In S440, the gain error is calculated by the same method as the method of calculating the gain error Gd described above with reference to FIG. Specifically, the amplitude K1 of the sensor value of the current sensor set to "during failure determination" or "failure" as the failure detection current value is obtained from the plus peak and the minus peak of the sensor value. Further, for the sensor value of the other current sensor, the amplitude K2 is obtained using at least one of the plus peak and the minus peak of the sensor value. Then, the ratio between them, that is, K2/K1 is calculated as a gain error.

In S450, the correction process is started for the failure detection current value which is the sensor value of the current sensor in the "failure" state. That is, with respect to the sensor value of the current sensor, until the current sensor becomes the “normal” state or the “discard” state, the above-mentioned equation ( The fault correction value is calculated according to 1). That is, the current sensor may change to the “recovery determination in progress” state in S460 to be described later and further to the “recovery” state in S580 to be described later. Until the "normal" state or the "discard" state is reached, the fault correction value is calculated by performing a correction calculation on the fault detection current value. In S460, the state of the current sensor in the "fault" state is set to "restoring determination".

Returning to FIG. 4, the description will be continued. When a negative determination is made in S130, the process proceeds to S150. In S150, it is determined whether one state of the first current sensor and the second current sensor is "restoring determination" and the other state is "normal" or "restoring". When a negative determination is made in S150, the current sensor monitoring process ends. If an affirmative decision is made in S150, the operation proceeds to S160.

In S160, restoration/discard determination processing is executed. Details of the restoration/discard determination processing are as shown in FIG. 7. When the control device 13 proceeds to the restoration/discard determination processing, in S510, it is determined whether or not the ratio between the currently calculated failure correction value and the sensor value of the normal current sensor matches the normal ratio. For example, in the case of the operation example of FIG. 3, whether or not the ratio between the U-phase second failure correction value IuBc and the U-phase first sensor value IuA matches the normal ratio of 1:1, in other words, the difference between the two values. Is less than or equal to the threshold value.

When the ratio between the failure correction value and the sensor value of the normal current sensor matches the normal ratio, in S520, the counter value of the recovery counter (hereinafter, recovery counter value) is incremented by 1 from the current value. After the processing of S520, the process proceeds to S550.

If the ratio between the failure correction value and the sensor value of the normal current sensor does not match the normal ratio in S510, the counter value of the discard counter (hereinafter, discard counter value) is incremented by 1 in S530. In S540, the recovery counter value is cleared to 0. The initial values of the recovery counter value and the discard counter value are both 0.

The process of clearing the recovery counter value in S540 may be omitted. On the contrary, the discard counter value may be cleared to 0 before or after the recovery counter value is incremented by 1 in S520.

In S550, it is determined whether the discard counter value is equal to or greater than the discard threshold. If the discard counter value is equal to or greater than the discard threshold value, the state of the current sensor in the “restoring determination” state is set to “discard” in S560.

If the discard counter value is less than the discard threshold value in S550, it is determined in S570 whether or not the recovery counter value is greater than or equal to the recovery threshold value. If the restoration counter value is not greater than or equal to the restoration threshold value, the current sensor monitoring process ends. If the restoration counter value is equal to or greater than the restoration threshold value, the state of the current sensor in the “restoring determination” state is set to “restoration” in S580.

(1-4) Phase Current Calculation Process Next, the phase current calculation process executed by the control device 13 will be described with reference to FIG. 8. After activation, the control device 13 repeatedly executes the phase current calculation process of FIG. 8 in a predetermined control cycle during a predetermined current detection period in which the current value of each phase should be detected. The phase current calculation process is actually executed in the control device 13 by the above-described CPU according to the program of the phase current calculation process stored in the memory.

The phase current calculation process is individually executed for each of the U, V, and W phases. That is, the phase current calculation process for calculating the U-phase current, the phase current calculation process for calculating the V-phase current, and the phase current calculation process for calculating the W-phase current are performed in parallel as multitasks, for example. Will be executed.

When the control device 13 starts the phase current calculation process in FIG. 8, in S610, the states of the first current sensor and the second current sensor are both “normal”, or one is “normal” and the other is “normal”. It is determined whether the setting is changed from "normal" to "during failure determination". The state in which the setting is changed from "normal" to "during failure determination" is currently "during failure determination", and the state before switching to "during failure determination" is "normal". It means that.

If an affirmative decision is made in S610, the operation proceeds to S620. In S620, the sum of the sensor values is calculated as the current value of the phase. That is, for example, in the case of the U phase, the sum of the U phase first sensor value IuA and the U phase second sensor value IuB is calculated as the U phase current value Iu.

When a negative determination is made in S610, the process proceeds to S630. In S630, it is determined whether or not one of the states of the first current sensor and the second current sensor is “normal” and the other is “fault”, “recovery determination in progress”, or “discard”.

If an affirmative decision is made in S630, the operation proceeds to S640. In S640, the sensor value of the current sensor whose status is "fault", "recovery determination in progress" or "discard" is invalidated, and the phase of the relevant phase is calculated by the above-described interpolation calculation using the sensor value of the current sensor in any other status. Calculate the current value. In the operation example of FIG. 3, the process of calculating a value twice the U-phase first sensor value IuA as the U-phase current value Iu between times t4 and t8 corresponds to the process of S640.

When a negative determination is made in S630, the sensor value of the current sensor whose state is not “normal” is replaced with the failure correction value. Then, the sum of the failure correction value and the sensor value of the current sensor in the “normal” state is calculated as the current value of the phase. In the operation example of FIG. 3, the process of calculating the sum of the U-phase first sensor value IuA and the U-phase second failure correction value IuBc as the U-phase current value Iu after time t8 corresponds to the process of S650. ..

(1-5) Effects of the Embodiment According to the embodiment described above, the following effects (1a) to (1) are achieved.
(1a) In the present embodiment, it is determined for each phase whether or not each current sensor is normal based on the ratio of the detected current value of each current sensor provided in the two branch paths. Then, if either one of the two current sensors has failed, which one has failed is specified. Specifically, the current value is calculated by dividing the sensor value of one current sensor by the branch ratio of the branch path provided with the current sensor, and the deemed current value and the other two-phase sensor values are calculated. Calculate the three-phase sum value of. Then, when the three-phase total sum value does not satisfy the normal condition, the failure of the one current sensor is determined.

Therefore, when any one of the current sensors fails, the failed current sensor can be detected quickly and accurately.
(1b) Instead of immediately determining a failure due to the fact that the three-phase sum value does not satisfy the normal condition, when the state in which the three-phase sum value does not satisfy the normal condition continues for more than the failure determination threshold, It is determined to be a failure. Therefore, it is possible to accurately determine the failure.

(1c) If one of the current sensors is officially determined to be faulty, the sensor value of the fault current sensor is invalidated. Then, as the current value of the branch bar provided with the fault current sensor, a fault correction value obtained by a correction calculation using the sensor value of the fault current sensor is used instead of the actual sensor value.

Further, when performing the correction calculation, the offset error and the gain error are calculated in advance. Then, after the offset error and the gain error are obtained, the correction calculation is performed using them.

Therefore, even if any of the current sensors fails, the sensor value of the failed current sensor is corrected to the failure correction value by the correction calculation, and therefore the current value of the phase is accurately measured using the failure correction value. It can be calculated.

(1d) When one of the current sensors is officially determined to be defective, until the offset error and the gain error for the correction calculation are obtained, the phase is calculated by the interpolation calculation using the sensor value of the other normal current sensor. The current value of is calculated. Therefore, until the offset error and the gain error are obtained, the calculation result of the current value of the phase can be maintained at a level where there is no practical problem.

(1e) Even if the offset error and the gain error are obtained and the failure correction value can be calculated, the failure correction value is not immediately used for calculating the current value of the phase, and the failure correction value is a practical problem. Check if there is no precision. Specifically, it is determined whether the difference between the failure correction value and the normal sensor value is less than or equal to the threshold value. Then, when the determination that the difference is less than or equal to the threshold value continues continuously for the failure determination threshold value times or more, the failure correction value is determined to be a value that causes no practical problem, and thereafter, the failure correction value is used. To calculate the current value of the phase. Therefore, the reliability of the phase current calculated using the failure correction value can be improved.

(1-6) Correspondence between Claims and Claims Here, the correspondence between the wording of the embodiment and the claims will be described. The control device 13 corresponds to a current detection device. The inverter 12 corresponds to a drive circuit. The bus bars 21, 22, 23 of each phase correspond to the supply path. Each branch bar 21a, 21b, 22a, 22b, 23a, 23b corresponds to a branch path.

The processing of S210 to S220 in FIG. 5 corresponds to the processing of the normality determining unit. The process of S240 in FIG. 5 corresponds to the process of the three-phase total sum calculation unit. The processing of S250 and S310 of FIG. 5 corresponds to the processing of the failure determination unit. The process of S410 of FIG. 6 corresponds to the process of the fault side peak acquisition unit and the normal side peak acquisition unit. The process of S430 in FIG. 6 corresponds to the process of the offset error calculation unit. The process of S440 in FIG. 6 corresponds to the process of the gain error calculation unit. The process of S450 of FIG. 6 corresponds to the process of the failure correction value calculation unit. The process of S510 in FIG. 7 corresponds to the process of the correction result determination unit. The processing of S640 and S650 in FIG. 8 corresponds to the processing of the abnormal phase current calculation unit.

[2. Other Embodiments]
Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications can be implemented.

(2-1) The number of branching of the bus bar for each phase, that is, the number of branching bars may be appropriately determined. That is, in the above embodiment, the two-branch configuration has two branch bars, but three or more branches may be used.

(2-2) It is not necessary to match the number of branches for each phase. For example, the number of branches of each phase may be appropriately determined such that the U phase has two branches and the V phase and the W phase have three branches, or the number of branches is different for each phase.

(2-3) For each phase, the branch ratios of the plurality of branch paths in the phase may be appropriately determined. For example, in the case of bifurcation, the bifurcation is not limited to bisection as in the above embodiment, and one bifurcation ratio may be less than 50% and the other bifurcation ratio may be greater than 50%.

(2-4) When the number of branches is three or more, and when one of the current sensors of each branch bar is determined to be in failure, the deemed current value is not determined to be in failure. It may be calculated by appropriately using the sensor values of the two or more current sensors. For example, the deemed current value may be calculated by using only one of the sensor values of the other two or more current sensors that are not determined to be faulty, or by using any two or more of them. The deemed current value may be calculated.

The calculation procedure in the case of calculating the considered current value using any two or more is as follows, for example. That is, each of the two or more sensor values used to calculate the deemed current is divided by the corresponding branch ratio. Then, the sum of the division results is set as the deemed current value.

(2-5) The motor to which the technique of the present disclosure can be applied is not limited to the synchronous motor having the permanent magnet as the field magnet, which is exemplified in the above embodiment. The present disclosure can be applied to various three-phase motors that can operate with three-phase current.

(2-6) In the determination processing of S250 based on the three-phase sum value, all the current sensors of the same phase may be in the "failure" state. In that case, the control device 13 does not calculate the current value of the phase using at least the sensor value of the phase, and controls the motor 10 using the sensor values of the two phases other than the phase. You may

(2-7) The fact that the current sensor is a through type is merely an example, and what kind of current sensor may be used may be appropriately determined.
(2-8) By implementing a plurality of functions of one component in the above embodiment by a plurality of components, or by implementing a single function of one component by a plurality of components Good. Further, a plurality of functions of a plurality of constituent elements may be realized by one constituent element, or one function realized by a plurality of constituent elements may be realized by one constituent element. Moreover, you may omit a part of structure of the said embodiment. Further, at least a part of the configuration of the above-described embodiment may be added or replaced with the configuration of the other above-described embodiment. Note that all aspects included in the technical idea specified by the wording recited in the claims are embodiments of the present disclosure.

DESCRIPTION OF SYMBOLS 1... Motor drive device, 10... Motor, 11... Battery, 12... Inverter, 13... Control device, 13a... CPU, 13b... Memory, 21... U phase bus bar, 21a... U phase 1st branch bar, 21b... U phase Second branch bar, 22... V-phase bus bar, 22a... V-phase first branch bar, 22b... V-phase second branch bar, 23... W-phase bus bar, 23a... W-phase first branch bar, 23b... W-phase second Branch bar, UA... U-phase first current sensor, UB... U-phase second current sensor, VA... V-phase first current sensor, VB... V-phase second current sensor, WA... W-phase first current sensor, WB... W-phase second current sensor.

Claims (5)

A plurality of currents of the phase are provided in a predetermined branch ratio in each of the current supply paths (21, 22, 23) for each phase from the drive circuit (12) that supplies the three-phase current to the motor (10) to the motor. A plurality of branch paths (21a, 21b, 22a, 22b, 23a, 23b) configured to be branched and rejoined are provided, and a current sensor (current sensor for detecting a current flowing through the branch path for each of the branch paths ( UA, UB, VA, VB, WA, WB) used in the motor drive device (1), and each phase is detected by each of the current sensors provided in the plurality of branch paths of the phase. A current detecting device (13) configured to detect a sum of detected current values, which are current values, as a current value of the phase,
Each of the phases, based on the ratio of the detected current value by each of the current sensors provided in the plurality of branch paths of the phase, and the ratio of the branch ratio in the phase, the plurality of branches of the phase. A normality determination unit (13, S210, S220) for determining whether or not all the current sensors provided on the path are normal;
When the normality determining unit determines that all of the phases are not normal, the detected current value of the current sensor is set to the current sensor for each of the current sensors in the abnormal phase that is the determined phase. Is a sum of an abnormal phase deemed current value that is a value divided by the branching ratio of the branching path provided with, and each of the detected current values of each of the current sensors in two phases other than the abnormal phase. , A three-phase total sum calculation unit (13, S240) for calculating a three-phase total sum value,
When the three-phase sum total value calculated by the three-phase sum total calculation unit does not satisfy a specific normal condition, the detected current used in the calculation of the abnormal phase deemed current value included in the three-phase sum total value A failure determination unit (13, S250, S310) that determines a failure of the current sensor that has detected a value;
A current detection device comprising: The current detection device according to claim 1, wherein
When a failure of the current sensor is determined by the failure determination unit, the detected current value by the current sensor that is determined to be the failure is invalidated, and detection is made invalid among the detected current values in the abnormal phase. At least one of the other detected current values other than the current value, and the current of the abnormal phase based on the branch ratio of the branch path provided with the current sensor detecting the at least one detected current value. An electric current detection device provided with the abnormal phase electric current calculation part (13, S640) which calculates a value. The current detection device according to claim 1 , wherein
When the failure determination unit determines a failure of the current sensor, the current sensor determined to be the failure in the abnormal phase is used as a failure current sensor, and the failure detection current value that is the detection current value by the failure current sensor. The failure-side peak acquisition unit (13, S410) that acquires the maximum value and the minimum value in the process of increasing and decreasing periodically.
The maximum value in the process of periodically increasing or decreasing the normal detection current value that is the detection current value by the normal current sensor, using at least one current sensor other than the fault current sensor in the abnormal phase as the normal current sensor. And a normal-side peak acquisition unit (13, S410) that acquires at least one of the minimum value and
The amplitude of the normal detection current value based on at least one of the maximum value and the minimum value of the normal detection current value acquired by the normal-side peak acquisition unit, in the branch path provided with the fault current sensor The value obtained by multiplying the ratio of the branch ratio and the branch ratio of the branch path provided with the normal current sensor, as the fault side normal amplitude which is the amplitude of the current that should be originally detected by the fault current sensor, Calculate a gain error that is a ratio between the fault-side normal amplitude and the actual amplitude of the fault-detection current value based on the maximum value and the minimum value of the fault-detection current value acquired by the fault-side peak acquisition unit. A gain error calculation unit (13, S440)
Offset that is the difference between the amplitude center value of the failure detection current value and the normal value of the normal detection current value based on the maximum value and the minimum value of the failure detection current value acquired by the failure side peak acquisition unit An offset error calculation unit (13, S430) for calculating an error;
The fault correction is performed by adding the offset error calculated by the offset error calculation unit to the fault detection current value, and further multiplying the addition result by the gain error calculated by the gain error calculation unit. A failure correction value calculation unit (13, S450) for calculating a value,
If the fault correction value is calculated by the previous SL fault correction value calculation unit, and the fault correction value, thus calculated, and the detected current value by each of the other said current sensor other than the fault current sensor in the abnormality phase An abnormal phase current calculation unit (S650) for calculating the sum of the above as an abnormal phase current value;
A current detection device comprising. The current detection device according to claim 3,
When the failure correction value is calculated by the failure correction value calculation unit, the ratio of the failure correction value and the current value detected by the current sensor other than the failure current sensor in the abnormal phase corresponds to A correction result determination unit (13, S510) for determining whether or not the ratio of the branching ratio
The abnormal phase current calculation unit, when it is determined by the correction result determination unit to match, the failure correction value and the detected current value of each of the current sensors other than the failure current sensor in the abnormal phase Calculating the sum as the current value of the abnormal phase,
Current detection device. The current detection device according to any one of claims 1 to 4,
In each of the phases, there are two branch paths,
In each of the phases, the two branch paths are configured so that the current of the phase is divided into two and branched.
Current detection device.

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