JP2007282299A - Fault diagnoser for voltage sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently diagnose the fault of a voltage sensor without applying a voltage, etc. for a fault diagnosis. <P>SOLUTION: The voltage sensor 15 of this fault diagnoser computes the output Pac1 of an AC motor 6 based on three-phase AC voltage commands vu<SP>*</SP>, vv<SP>*</SP>and vw<SP>*</SP>of an inverter 4, and current detected values iu, iv and iw of the current sensors 9a-9c, and computes the output Pac2 of the AC motor 6 based on a torque command Tmg and motor rotational speed ω. If the computed output Pac1 and the computed Pac2 do not accord with each other, it is determined that a fault has occurred in the inverter voltage sensor 5. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an apparatus for diagnosing a failure of a voltage sensor.

  Conventionally, a device for diagnosing a failure of a DC voltage sensor by further superimposing a voltage on a voltage applied to a motor is known (see Patent Document 1).

JP 2005-117756 A

  However, the conventional failure diagnosis apparatus has a problem in that failure diagnosis is not efficient because a superimposed voltage is required for failure diagnosis.

(1) In a fault diagnosis device for a voltage sensor used in a system for converting a DC voltage of a battery into an AC voltage by an inverter and supplying the AC voltage to an AC motor, calculation is performed using at least the DC voltage of the battery detected by the voltage sensor. Based on the voltage command value of the inverter and the current flowing from the inverter to the AC motor, the output of the AC motor (hereinafter referred to as the first motor output) is calculated, and based on the torque command value of the AC motor and the motor rotation speed. The output of the AC motor (hereinafter referred to as the second motor output) is calculated, and the failure of the voltage sensor is detected based on the first motor output and the second motor output.
(2) A first voltage sensor for detecting a battery voltage and a voltage input to the inverter from the battery, which are used in a system for converting a DC voltage of the battery into an AC voltage by an inverter and supplying the AC voltage to the AC motor. A failure diagnosis device for a voltage sensor that diagnoses a failure of a second voltage sensor is based on a first voltage detected by the first voltage sensor and a second voltage detected by the second voltage sensor. Thus, it is detected that a failure has occurred in at least one of the voltage sensors. In addition, at least using the voltage detected by the second voltage sensor, the output of the AC motor (hereinafter referred to as the first motor output) is calculated, and without using the voltage detected by the second voltage sensor, The output of the AC motor (hereinafter referred to as the second motor output) is calculated. When it is detected that a failure has occurred in at least one of the voltage sensors, the voltage sensor in which the failure has occurred is identified based on the first motor output and the second motor output.

  The voltage sensor failure diagnosis apparatus according to the present invention can diagnose a failure of a voltage sensor without applying a failure diagnosis voltage or the like.

  FIG. 1 is a block configuration diagram when a voltage sensor failure diagnosis apparatus according to an embodiment is applied to a hybrid vehicle. The DC voltage of the battery 1 composed of a plurality of cells is converted into a three-phase AC voltage in the inverter 4 on the basis of a command from the motor controller 10 and applied to the AC motor 6 that is a vehicle driving source. . The three-phase AC motor 6 is a motor generator that can generate electric power by performing a regenerative operation when the vehicle is decelerated or the like. The AC voltage generated by the AC motor 6 performing the regenerative operation is converted into a DC voltage by the inverter 4 and used for charging the battery 1.

  The battery voltage sensor 2 detects the total voltage VBf of the battery 1. The battery voltage Vbf detected by the battery voltage sensor 2 is transmitted to the vehicle controller 8. A relay 3 is provided between the battery 1 and the inverter 4. The inverter voltage sensor 5 detects a voltage downstream of the relay 3, that is, a voltage VIf (hereinafter referred to as an inverter voltage VIf) input from the battery 1 to the inverter 4.

  The rotation angle sensor 7 is, for example, a resolver and outputs a signal corresponding to the rotation angle of the AC motor 6. Current sensors 9a, 9b, and 9c detect U-phase current iu, V-phase current iv, and W-phase current iw flowing from inverter 4 to AC motor 6, respectively. The battery temperature sensor 20 detects the temperature of the battery 1. The vehicle controller 8 controls the entire vehicle.

  The motor controller 10 includes a three-phase / two-phase conversion unit 11, a current command unit 12, a current control unit 13, a two-phase / three-phase conversion unit 14, a voltage sensor diagnosis unit 15, A magnetic pole position detector 16, a motor rotation speed detector 17, and a PWM converter 21. In the control calculation performed inside the motor controller 10, among the currents flowing through the three-phase AC motor, the direction of the excitation current component is set to the d-axis, and the direction of the torque current component is set to the q-axis orthogonal to the d-axis. A rotational orthogonal coordinate system (dq coordinate system) is used. The dq coordinate system is a coordinate system that rotates in synchronization with the motor rotation.

  The magnetic pole position detector 16 detects the magnetic pole position θ of the AC motor 6 based on the signal output from the rotation angle sensor 7. The motor rotation speed detection unit 17 detects the rotation speed ω of the AC motor 6 based on the signal output from the rotation angle sensor 7.

Based on the magnetic pole position θ detected by the magnetic pole position detector 16, the three-phase / 2-phase converter 11 converts the current values iu, iv, iw detected by the current sensors 9a to 9c into excitation current components d. The shaft current id is converted into a q-axis current iq which is a torque current component, and is output to the current controller 13. The current command unit 12 determines the torque command value Tmg input from the vehicle controller 8, the motor rotation speed ω detected by the motor rotation number detection unit 17, and the inverter voltage VI output from the voltage sensor diagnosis unit 15 described later. Based on this, the d-axis current command value id ^* and the q-axis current command value iq ^* are calculated. The calculated current command values id ^* and iq ^* are sent to the current control unit 13.

The current control unit 13 performs, for example, a PI (proportional / integral) calculation in order to make the actual currents id and iq of the d-axis and q-axis coincide with the current command values id ^* and iq ^* , respectively, thereby calculating the d-axis voltage. The command value vd ^* and the q-axis voltage command value vq ^* are calculated. The two-phase / 3-phase converter 14 converts the d-axis voltage command value vd ^* and the q-axis voltage command value vq ^* into a three-phase AC voltage command value vu ^* based on the magnetic pole position θ detected by the magnetic pole position detector 16 ^. , Vv ^* , vw ^* . The converted three-phase AC voltage command values vu ^* , vv ^* , vw ^* are sent to the PWM converter 21.

The PWM converter 21 compares a three-phase AC voltage command value with a carrier wave (generally a triangular wave) of about 10 kHz, and a three-phase AC switching signal Pu, which is an ON / OFF signal for driving the power conversion element. Pv and Pw are generated. Here, since the peak of the carrier wave is equivalent to ± (battery voltage / 2), the three-phase AC voltage command values vu ^* , vv ^* , and vw ^* are represented by the inverter voltage VI as shown in the following expressions (a) to (c). And Pu, Pv, and Pw are obtained by comparison with the carrier wave.
vu ^* 1 = vu ^* / (VI / 2) (a)
vv ^* 1 = vv ^* / (VI / 2) (b)
vw ^* 1 = vw ^* / (VI / 2) (c)

  The inverter 4 converts the DC voltage of the battery 1 into a three-phase AC voltage by a power conversion element such as an IGBT based on the three-phase AC switching signals Pu, Pv, and Pw.

  The voltage sensor failure diagnosis unit 15 diagnoses the presence or absence of a failure in the voltage sensors 2 and 5 based on the battery voltage VBf detected by the battery voltage sensor 2 and the inverter voltage VIf detected by the inverter voltage sensor 5. When a failure of one of the voltage sensors is detected, a process of identifying the failed voltage sensor is performed. When a failure of the battery voltage sensor 2 is detected, a battery voltage sensor abnormality signal is output to the vehicle controller 8. A failure diagnosis method for the voltage sensors 2 and 5 will be described later.

  The voltage sensor failure diagnosis unit 15 also performs a process of calculating the control battery voltage VB and the control inverter voltage VI. When no failure has occurred in voltage sensors 2 and 5, control battery voltage VB and control inverter voltage VI are detected by battery voltage VBf and inverter voltage sensor 5 detected by battery voltage sensor 2, respectively. Equal to the inverter voltage VIf. The calculated control battery voltage VB is output to the vehicle controller 8, and the control inverter voltage VI is output to the current command unit 12 and the PWM conversion unit 21.

  FIG. 2 is a flowchart showing the contents of the failure diagnosis process performed in the voltage sensor diagnosis unit 15. When the vehicle is activated and the power supply of the motor controller 10 is turned on, the voltage sensor diagnosis unit 15 starts the process of step S10.

In step S10, the battery voltage VBf detected by the battery voltage sensor 2 and the inverter voltage VIf detected by the inverter voltage sensor 5 are acquired, and the process proceeds to step S20. In step S20, it is determined whether or not the relationship of the following expression (1) holds, that is, whether or not the absolute value of the difference between the battery voltage VBf and the inverter voltage VIf is greater than a predetermined value α. However, the predetermined value α is a predetermined threshold value for diagnosing a failure of the battery sensors 2 and 5.
| VIf−VBf |> α (1)

  When both the battery voltage sensor 2 and the inverter voltage sensor 5 are normal, the difference between the battery voltage VBf and the inverter voltage VIf is equal to or less than a predetermined value α. If it is determined that the relationship of Expression (1) does not hold, both the battery voltage sensor 2 and the inverter voltage sensor 5 are determined to be normal, and the process proceeds to step S70. In step S70, the battery voltage sensor abnormality signal is turned off, and the process returns to step S10. In this case, the control battery voltage VB is the voltage VBf detected by the voltage sensor 2, and the control inverter voltage VI is the voltage VIf detected by the inverter voltage sensor 5.

  On the other hand, if it is determined that the relationship of Expression (1) holds, it is determined that at least one of the battery voltage sensor 2 and the inverter voltage sensor 5 has failed, and the process proceeds to step S30.

In step S30, in order to determine which voltage sensor has failed, the output estimated value Pac1 of the three-phase AC motor 6 is calculated from the following equation (2), and from the following equation (3): The estimated output value Pac2 of the three-phase AC motor is calculated. The estimated output value Pac1 is set to the three-phase AC voltage command values vu ^* , vv ^* , vw ^* calculated by the two-phase / three-phase converter 14 and the current detection values iu, iv, iw of the current sensors 9a to 9c. Calculate based on Further, the estimated output value Pac2 is calculated based on the torque command value Tmg input from the vehicle controller 8, the motor rotation speed ω detected by the motor rotation speed detection unit 17, and the motor loss Wmg.
Pac1 = vu ^** iu + vv ^** iv + vw ^** iw (2)
Pac2 = ω × Tmg + Wmg (3)
However, the loss Wmg is a motor loss when the motor is driven at the operating point (ω, Tmg), and the motor loss for each operating point is obtained beforehand by experimentation or the like and referred to as a table. Ask for.

Here, when the inverter voltage sensor 5 is normal, Pac1≈Pac2. However, when the PWM converter 21 calculates the three-phase AC switching signals Pu, Pv, and Pw, the control inverter voltage VI (when the failure of the inverter voltage sensor 5 is not detected, the value of VI = VIf is For example, when the voltage detection value of the inverter voltage sensor 5 is smaller than the actual voltage value, the actual voltage applied to the AC motor 6 is the three-phase AC voltage command value vu. ^It becomes larger than ^* , vv ^* , and vw ^* . Accordingly, since the actual currents id and iq also do not match the current command values id ^* and iq ^* , the current control unit operates to match the actual currents id and iq with the current command values id ^* and iq ^* . Finally, the three-phase AC voltage command values vu ^* , vv ^* , vw ^* become smaller. For this reason, when a failure has occurred in the inverter voltage sensor 5, Pac1 ≠ Pac2.

When the estimated output values Pac1 and Pac2 of AC motor 6 are calculated in step S30, the process proceeds to step S40. In step S40, it is determined whether or not the relationship of the following equation (4) holds, that is, whether or not the absolute value of the difference between the output estimated values Pac1 and Pac2 is greater than a predetermined value P0.
| Pac1-Pac2 |> P0 (4)

  If it is determined that the relationship of Expression (4) holds, it is determined that a failure has occurred in the inverter voltage sensor 5, and the process proceeds to step S50. On the other hand, if it is determined that the relationship of Expression (4) does not hold, it is determined that a failure has occurred in the battery voltage sensor 2 since no failure has occurred in the inverter voltage sensor 5, and the process proceeds to step S60.

In step S50, the control inverter voltage VI is estimated. The inverter voltage is smaller than the battery voltage VBf by the potential difference ΔVB1 of the resistance of the harness between the battery 1 and the inverter 5 and the error ΔVB2 due to communication delay. That is, the control inverter voltage VI (n) at time T (n) is expressed by the following equation (5).
VI (n) = VBf (n) − (ΔVB1 (n) + ΔVB2 (n)) (5)
However, VBf (n) is a voltage value detected by the battery voltage sensor 2 at time T (n), ΔVB1 (n) is a value of ΔVB1 at time T (n), and ΔVB2 (n) is time T (n). This is the value of ΔVB2 in n).

The potential difference ΔVB1 of the resistance of the harness between the battery 1 and the inverter 5 is the motor rotation speed at time T (n) is ω (n), the torque command value is Tmg (n), and between the battery 1 and the inverter 5 When the resistance value of the harness is R, it is represented by the following equation (6).
ΔVB1 (n) = R · (ω (n) · Tmg (n) / VBf (n)) (6)

The error ΔVB2 due to the communication delay is caused by the battery voltage VBf detected by the battery voltage sensor 2 being input to the voltage sensor 15 via the communication line, that is, the vehicle controller 8, and It is obtained from the change ΔP2 of the motor output calculated based on the rotational speed ω and the torque command value Tmg. The motor output change ΔP2 is expressed by the following equation (7).
ΔP2 = ω (n) · Tmg (n) −ω (n−1) · Tmg (n−1) (7)
However, ω (n−1) is the motor rotation speed at time T (n−1), and Tmg (n−1) is the torque command value at time T (n−1).

  FIGS. 3A and 3B are diagrams showing the relationship between the motor output change ΔP2 and the battery voltage change (error due to communication delay) ΔVB2. 3A is a diagram showing a relationship when the SOC of the battery 1 is a predetermined value SOC1, and FIG. 3B is a diagram showing a relationship when the SOC of the battery 1 is a predetermined value SOC2 (SOC2> SOC1). It is. When the temperature of the battery 1 is the same, the value of ΔVB2 with respect to ΔP2 becomes smaller when the SOC is higher than when the SOC is low. When the SOC of the battery 1 is the same, the value of ΔVB2 with respect to ΔP2 decreases as the temperature of the battery 1 increases.

  Here, as shown in FIGS. 3 (a) and 3 (b), an error ΔVB2 due to a communication delay with respect to the SOC of the battery 1, the battery temperature, and the motor output change ΔP2 is obtained in advance by experimentation and tabulated. By referring to this table, an error ΔVB2 due to communication delay is obtained. The battery temperature is a value detected by the battery temperature sensor 20, and the SOC of the battery 1 can be calculated by a known method.

  In step S50, since the battery voltage sensor 2 is normal, the voltage value VBf detected by the battery voltage sensor 2 is set to the control battery voltage VB and the battery voltage sensor abnormality signal is turned off. When the control inverter voltage VI and the control battery voltage VB are obtained in step S50, the process returns to step S10.

On the other hand, in step S60, since the inverter voltage sensor 5 is normal, the control inverter voltage VI uses the voltage value VIf detected by the inverter voltage sensor 5 to perform a process of estimating the control battery voltage VB. The control battery voltage VB (n) at time T (n) is expressed by the following equation (8). Again, (n) following each parameter means that the value is detected at time T (n).
VB (n) = VIf (n) + R · (ω (n) · Tmg (n) / VIf (n)) (8)

  When the control battery voltage VB is obtained, it is transmitted to the vehicle controller 8 together with the battery voltage sensor abnormality signal turned on, and the process returns to step S10. The vehicle controller 8 that has received the battery voltage sensor abnormality signal informs the user that a failure has occurred in the battery voltage sensor 2, for example, by turning on an indicator (not shown).

According to the failure diagnosis device for a voltage sensor in one embodiment, the failure of the voltage sensors 2 and 5 is diagnosed and detected by the voltage sensor in which the failure is detected by the following procedures (I) to (III). Estimate the voltage value.
(I) The battery voltage VBf detected by the battery voltage sensor 2 and the inverter voltage VIf detected by the inverter voltage sensor 5 are compared. If the absolute value of the difference between the two is larger than a predetermined value α, at least one of the voltages It is determined that a failure has occurred in the sensor.
(II) Based on the three-phase AC voltage command values vu ^* , vv ^* , vw ^* and the three-phase AC current detection values iu, iv, iw, the estimated output value Pac1 of the AC motor 6 is calculated, and at least the torque Based on the command value Tmg and the motor rotation speed ω, the estimated output value Pac2 of the AC motor 6 is calculated. If the absolute value of the difference between the output estimated values Pac1 and Pac2 is larger than the predetermined value P0, it is determined that a failure has occurred in the inverter voltage sensor 5, and the absolute value of the difference between Pac1 and Pac2 is less than the predetermined value P0. For example, it is determined that a failure has occurred in the battery voltage sensor 2.
(III) If it is determined that a failure has occurred in the inverter voltage sensor 5, the voltage VBf detected by the battery voltage sensor 2, the potential difference ΔVB1 between the battery 1 and the inverter 5, and the error ΔVB2 due to communication delay Based on this, the value of the inverter voltage VI is estimated. When it is determined that a failure has occurred in the battery voltage sensor 2, the value of the battery voltage VB is determined based on the inverter voltage VIf detected by the inverter voltage sensor 5 and the potential difference between the battery 1 and the inverter 5. Is estimated.

  According to the voltage sensor failure diagnosis apparatus in the embodiment, after detecting the failure of at least one of the battery voltage sensor 2 and the inverter voltage sensor 5 by the method (I) described above, the method (II) Thus, the faulty voltage sensor is identified, so that efficient fault diagnosis using the existing configuration can be performed without using a fault diagnosis voltage or the like. Thereby, not only can the user know that one of the voltage sensors has failed, but also the user can be notified of the failed voltage sensor.

  According to the failure diagnosis device for a voltage sensor in one embodiment, when a failure in the inverter voltage sensor 5 is detected, the inverter voltage VI is estimated based on the voltage VBf detected by the battery voltage sensor 2, so that the inverter voltage VI It is possible to continue processing based on the above. Further, when the failure of the battery voltage sensor 2 is detected, the processing based on the inverter voltage VIf detected by the inverter voltage sensor 5 can be continuously performed. In particular, the voltage detected by the failed voltage sensor is estimated in consideration of the potential difference between the battery 1 and the inverter 5, so that the accuracy of voltage estimation can be improved.

  Further, in the circuit shown in FIG. 1, the voltage VBf detected by the battery voltage sensor 2 is input to the voltage sensor diagnosis unit 15 via the vehicle controller 8, so that an inverter voltage VI is also taken into account in consideration of errors due to communication delay. Therefore, the accuracy of voltage estimation can be further improved.

  The present invention is not limited to the embodiment described above. For example, instead of the battery voltage sensor 2, a cell voltage sensor that detects the voltage of each cell constituting the battery 1 may be provided. In this case, the battery voltage VBf is the sum of the cell voltages detected by the cell voltage sensor.

  In the above-described embodiment, the voltage sensor in which the failure has occurred is identified by the procedures (I) and (II). However, only the process (II) may be performed without performing the process (I). That is, the output estimated values Pac1 and Pac2 are calculated, and if the absolute value of the difference between the calculated Pac1 and Pac2 is larger than the predetermined value P0, it is determined that a failure has occurred in the inverter voltage sensor 5. According to this method, a failure of the inverter voltage sensor 5 can be detected.

In the above-described embodiment, at least the value of the inverter voltage VI is used to calculate the three-phase AC voltage command values vu ^* , vv ^* , vw ^* , but the battery voltage detected by the battery voltage sensor 2 is used. When the value of VBf is used, a failure of the battery voltage sensor 2 can be detected by the same method. That is, the output estimated values Pac1 and Pac2 are calculated, and if the absolute value of the difference between the calculated Pac1 and Pac2 is larger than the predetermined value P0, it is determined that the battery voltage sensor 2 has failed.

  In the above-described embodiment, an example in which the failure diagnosis device for a voltage sensor is applied to a hybrid vehicle has been described. However, it can be applied to an electric vehicle or a system other than a vehicle.

  The present invention is not limited by the type of battery 1, the type of inverter 4, the types of voltage sensors 2 and 5, the type of motor 6, and the like.

  The correspondence between the constituent elements of the claims and the constituent elements of the embodiment is as follows. That is, the motor controller 10 includes voltage command value calculation means, first motor output calculation means, second motor output calculation means, failure detection means, failure voltage sensor identification means, and voltage estimation means as current sensors 9a to 9c. Constitutes the current detection means, and the rotation angle sensor 7 and the motor rotation speed detection section 17 constitute the motor rotation speed detection means. In addition, the above description is an example to the last, and when interpreting invention, it is not limited to the correspondence of the component of said embodiment and the component of this invention at all.

1 is a block diagram when a voltage sensor failure diagnosis apparatus according to an embodiment is applied to a hybrid vehicle. Flow chart showing the contents of failure diagnosis processing performed in the voltage sensor diagnosis unit FIGS. 3A and 3B are diagrams showing the relationship between the motor output change ΔP2 and the battery voltage change (error due to communication delay) ΔVB2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Battery, 2 ... Battery voltage sensor, 3 ... Relay, 4 ... Inverter, 5 ... Inverter voltage sensor, 6 ... Three-phase alternating current motor, 7 ... Rotation angle sensor, 8 ... Vehicle controller, 9a, 9b, 9c ... Current sensor DESCRIPTION OF SYMBOLS 10 ... Motor controller, 11 ... 3 phase / 2 phase conversion part, 12 ... Current command part, 13 ... Current control part, 14 ... 2 phase / 3 phase conversion part, 15 ... Voltage sensor diagnostic part, 16 ... Magnetic pole position detection , 17 ... Motor rotation speed detection unit, 20 ... Battery temperature sensor, 21 ... PWM conversion unit

Claims (7)

In a fault diagnosis device for a voltage sensor used in a system that converts a DC voltage of a battery into an AC voltage by an inverter and supplies the AC voltage to an AC motor.
Voltage command value calculation means for calculating a voltage command value of the inverter using at least a DC voltage of the battery detected by the voltage sensor;
Current detection means for detecting a current flowing from the inverter to the AC motor;
Motor rotation speed detection means for detecting the rotation speed of the motor;
A first motor that calculates an output of the AC motor (hereinafter referred to as a first motor output) based on a voltage command value calculated by the voltage command value calculation unit and a current detected by the current detection unit. Output calculation means;
Second motor output calculation that calculates an output of the AC motor (hereinafter referred to as a second motor output) based on at least the torque command value of the AC motor and the motor rotation speed detected by the motor rotation speed detection means. Means,
A failure that detects a failure of the voltage sensor based on the first motor output calculated by the first motor output calculation unit and the second motor output calculated by the second motor output calculation unit A fault diagnosis apparatus for a voltage sensor, comprising: a detecting unit. A first voltage sensor that detects the voltage of the battery, and detects a voltage input from the battery to the inverter, which is used in a system that converts the DC voltage of the battery into an AC voltage by an inverter and supplies the AC voltage to the AC motor. In the voltage sensor failure diagnosis device for diagnosing the failure of the second voltage sensor,
At least one voltage sensor based on a voltage detected by the first voltage sensor (hereinafter referred to as a first voltage) and a voltage detected by the second voltage sensor (hereinafter referred to as a second voltage) A failure detection means for detecting that a failure has occurred;
First motor output calculation means for calculating an output of the AC motor (hereinafter referred to as a first motor output) using at least a voltage detected by the second voltage sensor;
Second motor output calculation means for calculating the output of the AC motor (hereinafter referred to as second motor output) without using the voltage detected by the second voltage sensor;
When the failure detection means detects that a failure has occurred in at least one of the voltage sensors, the first motor output calculated by the first motor output calculation means and the second motor output calculation A fault diagnosis device for a voltage sensor, comprising: fault voltage sensor specifying means for specifying a voltage sensor in which a fault has occurred based on a second motor output calculated by the means. The failure diagnosis device for a voltage sensor according to claim 2,
Voltage command value calculating means for calculating a voltage command value of the inverter using at least a voltage detected by the second voltage sensor;
Current detection means for detecting a current flowing from the inverter to the AC motor;
Motor rotation speed detection means for detecting the rotation speed of the AC motor,
The first motor output calculation means calculates the first motor output based on the voltage command value calculated by the voltage command value calculation means and the current detected by the current detection means,
The second motor output calculation means calculates the second motor output based on at least a torque command value of the AC motor and a motor rotation speed detected by the motor rotation speed detection means. Fault diagnosis device for voltage sensor. The more detailed calculation method of Pac1 and Pac2 In the fault diagnosis apparatus of the voltage sensor of Claim 3,
The first motor output calculation means is configured to output the first motor based on a three-phase AC voltage command value calculated by the voltage command value calculation means and a three-phase AC current detected by the current detection means. Calculate the output,
The second motor output calculation means calculates the second motor output based on a torque command value of the AC motor, a motor rotation speed detected by the motor rotation speed detection means, and a loss during motor driving. A fault diagnosis device for a voltage sensor, characterized by: In the fault diagnosis apparatus of the voltage sensor as described in any one of Claims 2-4,
If the absolute value of the difference between the first motor output and the second motor output is less than or equal to a predetermined threshold value, the fault voltage sensor specifying means is that a fault has occurred in the first voltage sensor Determining that if the absolute value of the difference between the first motor output and the second motor output is greater than the predetermined threshold, it is determined that a failure has occurred in the second voltage sensor. A fault diagnosis device for a voltage sensor. In the voltage sensor failure diagnosis device according to any one of claims 2 to 5,
Voltage estimation means is further provided for estimating a voltage detected by the voltage sensor whose failure is specified by the failure voltage sensor specifying means based on a voltage detected by a voltage sensor in which no failure has occurred. Fault diagnosis device for voltage sensor. The voltage sensor failure diagnosis device according to claim 6,
The voltage estimation means is detected by the voltage sensor in which the failure is specified based on at least a voltage detected by a voltage sensor in which no failure has occurred and a potential difference between the battery and the inverter. A voltage sensor failure diagnosis apparatus characterized by estimating a voltage.

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