JP5556635B2 - Vehicle and current detection device abnormality determination method - Google Patents

Description

  The present invention relates to a technique for determining an abnormality of a current sensor that detects a phase current of a three-phase AC motor mounted on a vehicle.

  In recent years, attention has been focused on hybrid vehicles, fuel cell vehicles, electric vehicles, and the like that travel with driving force from a motor as one of countermeasures for environmental problems. Such a vehicle is equipped with, for example, a three-phase AC motor that generates driving force. In order to appropriately control the drive of this three-phase AC motor, a technique for easily determining a failure of a current sensor by detecting a motor current of the same phase using a plurality of current sensors is known.

  For example, according to the current sensor failure detection method disclosed in Japanese Patent Application Laid-Open No. 2001-112295 (Patent Document 1), by detecting an arbitrary pair of alternating currents in a three-phase alternating current by each pair of current sensors. Which current sensor is in failure is determined.

JP 2001-112295 A

  However, in the current sensor failure detection method disclosed in the above-mentioned publication, motor currents in two phases are detected using four current sensors. From the viewpoint of reducing production costs, it is desirable to reduce the number of current sensors as much as possible.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a vehicle and a current detection device that can easily detect a failure of a current sensor and suppress an increase in production cost. An abnormality determination method is provided.

  A vehicle according to an aspect of the present invention includes a three-phase AC motor, a first current sensor for detecting a first current flowing in a first phase of the three phases, and a first phase different from the first phase. Second and third current sensors for detecting current flowing in the two phases, and a control unit for receiving the detection results from each of the first to third current sensors and controlling the three-phase AC motor; including. When it is determined that the second and third current sensors are in the normal state based on the detection results of the second and third current sensors, the control unit performs the first based on the detection results of the first current sensor. The first current sensor is abnormal when the magnitude of the first difference between the first amplitude of the current of the second phase and the second amplitude of the current of the second phase is greater than the first threshold value. It is determined that it is in a state.

  Preferably, the control unit has a second difference between the first detection value of the second current sensor and the second detection value of the third current sensor being smaller than the second threshold value. In this case, it is determined that the second and third current sensors are in a normal state.

  More preferably, the control unit determines that the first current sensor is in a normal state when the magnitude of the first difference is smaller than the first threshold value.

  More preferably, the second current sensor has a higher resolution than the third current sensor. When it is determined that the second and third current sensors are in the normal state, the control unit uses the second amplitude based on the detection result of the second current sensor and the first current sensor is in the abnormal state. It is determined whether or not there is.

  A vehicle according to another aspect of the present invention is different from the first phase in the three-phase AC motor, the first current sensor for detecting the first current flowing in the first phase of the three phases, and the first phase. Second and third current sensors for detecting the current flowing in the second phase, and a control unit for receiving the detection results from each of the first to third current sensors and controlling the three-phase AC motor Including. When the control unit determines that the first and second current sensors are in a normal state based on the detection results of the first and second current sensors, the control unit includes the first phase and the second phase. The third current when the magnitude of the difference between the first amplitude of one of the currents and the second amplitude of the current of the first phase based on the detection result of the third current sensor is greater than the threshold value. It is determined that the sensor is in an abnormal state.

  An abnormality determination method for a current detection device according to still another aspect of the present invention includes: a first current sensor for detecting a current flowing in a first phase of three phases of a three-phase AC motor; An abnormality determination method for determining an abnormality of a current detection device including second and third current sensors for detecting a current of a second phase different from a phase. The abnormality determination method includes a step of detecting a current of a first phase using a first current sensor, a step of detecting a current of a second phase using second and third current sensors, When it is determined that the second and third current sensors are normal based on the detection results of the second and third current sensors, the first current of the first phase based on the detection result of the first current sensor is determined. When the magnitude of the difference between the amplitude of 1 and the second amplitude of the current of the second phase is larger than the threshold value, it is determined that the first current sensor is in an abnormal state.

It is a figure which shows the whole structure of the vehicle which concerns on this Embodiment. It is a figure which shows the change of the motor current of each phase with respect to an electrical angle. It is a functional block diagram of MG-ECU mounted on the vehicle according to the present embodiment. It is a flowchart which shows the control structure of the program performed by MG-ECU mounted in the vehicle which concerns on this Embodiment. It is a timing chart which shows operation | movement of MG-ECU mounted in the vehicle which concerns on this Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  As shown in FIG. 1, vehicle 10 according to the present embodiment is a hybrid vehicle. The vehicle 10 includes a first motor generator (hereinafter referred to as MG) 12, a second MG 14, a PCU 16, a main battery 28, an auxiliary battery 100, and an air conditioner compressor (hereinafter referred to as A / C compressor). ) 102, a power management ECU (Electronic Control Unit) 300 (hereinafter referred to as P-ECU 300), an engine ECU 400, an engine 402, a power split device 404, and drive wheels 406. In the present embodiment, transmission 408 includes first MG 12, second MG 14, and power split device 404.

  Output shafts of first MG 12, second MG 14, and engine 402 are coupled to power split device 404. The vehicle 10 travels by driving force from at least one of the engine 402 and the second MG 14. The power generated by the engine 402 is divided into two paths by the power split device 404. One of the two paths is a path transmitted to the drive wheel 406, and the other is a path transmitted to the first MG 12.

  Each of first MG 12 and second MG 14 is, for example, a three-phase AC rotating electric machine including a rotor in which a permanent magnet is embedded. Each of first MG 12 and second MG 14 includes three stator coils of U, V, and W phases. One ends of the three U, V, and W phase stator coils of each of the first MG 12 and the second MG 14 are commonly connected to a neutral point. The other end of each phase is connected to the midpoint of the switching elements of the upper and lower arms of each phase.

  First MG 12 generates power using the power of engine 402 divided by power split device 404. For example, when SOC (State of Charge) indicating the remaining capacity of main battery 28 becomes lower than a predetermined value, engine 402 is started and power is generated by first MG 12. The generated electric power is supplied to the PCU 16.

  The second MG 14 generates a driving force using the electric power supplied from the PCU 16. The driving force of the second MG 14 is transmitted to the driving wheels 406. When the vehicle 10 is braked, the second MG 14 is driven by the drive wheels 406, and the second MG 14 operates as a generator. In this way, the second MG 14 operates as a regenerative brake that converts braking energy into electric power. The electric power generated by the second MG 14 is supplied to the main battery 28 via the PCU 16.

  Power split device 404 is a planetary gear including a sun gear, a pinion gear, a carrier, and a ring gear (all not shown). The pinion gear engages with the sun gear and the ring gear. The carrier supports the pinion gear so as to be capable of rotating, and is connected to the crankshaft of the engine 402. The sun gear is connected to the rotation shaft of the first MG 12. The ring gear is connected to the rotation shaft of second MG 14.

  The main battery 28 is a rechargeable DC power source, such as a secondary battery such as a nickel metal hydride battery or a lithium ion battery, or a large capacity capacitor.

  In the present embodiment, a case where the main battery 28 is mounted on the vehicle 10 as a main power source will be described. However, the present invention is not particularly limited to such a configuration. For example, in addition to the main battery 28, One or two or more sub-batteries may be mounted.

  PCU 16 includes an inverter 18, a boost converter 20, a DC / DC converter 22, a first capacitor 24, a system main relay (hereinafter referred to as SMR) 26, and an MG-ECU 200.

  Inverter 18 includes a first IPM (Intelligent Power Module) 32, a second IPM 34, a second capacitor 36, a discharge resistor 38, and a current detection device 58. Each of first IPM 32 and second IPM 34 is connected to first power line MPL and first ground line MNL in parallel with each other. First IPM 32 converts the DC power supplied from boost converter 20 into AC power and outputs the AC power to first MG 12. Second IPM 34 converts the DC power supplied from boost converter 20 into AC power and outputs the AC power to second MG 14.

  Further, first IPM 32 converts AC power generated in first MG 12 into DC power and outputs the DC power to boost converter 20. Second IPM 34 converts AC power generated in second MG 14 into DC power and outputs the DC power to boost converter 20.

  Note that each of the first IPM 32 and the second IPM 34 includes, for example, a bridge circuit including switching elements for three phases.

  The first IPM 32 includes U-phase, V-phase, and W-phase upper and lower arms. The upper and lower arms of each phase are connected in parallel between the first power line MPL and the first ground line MNL. The upper and lower arms of each phase include switching elements connected in series between the first power line MPL and the first ground line MNL.

  For example, the upper and lower arms of the U phase include switching elements Q3 and Q4. The V-phase upper and lower arms include switching elements Q5 and Q6. The upper and lower arms of the W phase include switching elements Q7 and Q8. Antiparallel diodes D3-D8 are connected to switching elements Q3-Q8, respectively. On / off of switching elements Q3-Q8 is controlled by an inverter drive signal from MG-ECU 200.

  As the switching elements Q3-Q8, for example, a power semiconductor switching element such as an IGBT (Insulated Gate Bipolar Transistor), a power MOS (Metal Oxide Semiconductor) transistor, or a power bipolar transistor is used.

  The second IPM 34 has the same configuration as the first IPM 32. Therefore, detailed description thereof will not be repeated.

  First IPM 32 drives first MG 12 by performing a switching operation in accordance with an inverter drive signal from MG-ECU 200. Second IPM 34 drives second MG 14 by performing a switching operation in accordance with an inverter drive signal from MG-ECU 200.

  A current detection device 58 is connected to MG-ECU 200. Current detection device 58 detects the motor current (phase current) of each phase flowing through first MG 12 and outputs the detected motor current to MG-ECU 200. Since the sum of the instantaneous values of the three-phase currents is zero, the current detection device 58 detects the motor current for the two phases of the first MG 12. The MG-ECU 200 calculates the remaining one-phase motor current from the detected two-phase motor current. For example, when the first MG 12 is controlled to generate a constant torque, each of the currents Iv, Iw and Iu of each phase has a current waveform whose phase is shifted by 120 ° as shown in FIG.

  The current detection device 58 includes a first current sensor 60, a second current sensor 62, and a third current sensor 64. First current sensor 60 detects the current of the first phase among the three phases of first MG 12. Each of second current sensor 62 and third current sensor 64 detects a current of a second phase different from the first phase among the three phases of first MG 12. In the present embodiment, the “first phase” is assumed to be the W phase, and the “second phase” is assumed to be the V phase. However, the present invention is not particularly limited thereto. The MG-ECU 200 receives detection results from each of the first current sensor 60, the second current sensor 62, and the third current sensor 64.

  That is, first current sensor 60 detects W-phase current Iw of first MG 12 and outputs a signal indicating detected current Iw to MG-ECU 200. Each of second current sensor 62 and third current sensor 64 detects V-phase current Iv of first MG 12 and outputs a signal indicating detected current Iv to MG-ECU 200. In the following description, the detection value of the V-phase current Iv detected by the second current sensor 62 is described as Iv1, and the detection value Iv2 of the V-phase current Iv detected by the third current sensor 64 is described. To do.

  In the present embodiment, the second current sensor 62 is described as having a higher resolution than the third current sensor 64, but the present invention is not limited to this, and the third current sensor 64 is not limited thereto. May have a higher resolution than the second current sensor 62, and the second current sensor 62 and the third current sensor 64 may have the same resolution.

  The MG-ECU 200 is connected to a current detection device that detects a motor current flowing through the second MG 14 and outputs the detected motor current to the MG-ECU 200. This current detection device has a configuration similar to that of the current detection device 58. Therefore, detailed description thereof will not be repeated.

  A first resolver 50 and a second resolver 52 are connected to MG-ECU 200. First resolver 50 detects rotation angle θ1 of the rotation shaft of first MG 12, and outputs the detected rotation angle θ1 to MG-ECU 200. The MG-ECU 200 can calculate the rotation speed and the angular speed ω1 (rad / s) of the first MG 12 based on the rotation angle θ1. Second resolver 52 detects rotation angle θ2 of the rotation axis of second MG 14 and outputs the detected rotation angle θ2 to MG-ECU 200. The MG-ECU 200 can calculate the rotation speed and the angular speed ω2 (rad / s) of the second MG 14 based on the rotation angle θ2.

  The first resolver 50 and the second resolver 52 may be omitted when the rotation angles θ1 and θ2 are directly calculated from the motor voltage and current by the MG-ECU 200.

  Further, MG-ECU 200 receives inverter information from inverter 18. The inverter information is, for example, at least one of the temperature of the inverter 18, the voltage and current on the boost converter 20 side, the current of each phase supplied to the first MG 12, and the current of each phase supplied to the second MG 14. Contains one piece of information. The inverter 18 is provided with various sensors (not shown) for acquiring the inverter information described above.

  MG-ECU 200 controls the operations of inverter 18 and boost converter 20 by software processing by executing a prestored program by a CPU (Central Processing Unit) (not shown) and / or hardware processing by a dedicated electronic circuit. .

  Main battery 28 is connected to boost converter 20 via SMR 26. Main battery 28 is connected to one end of second power line PL and one end of second ground line NL. The other end of second power line PL and the other end of second ground line NL are connected to boost converter 20.

  Based on a control signal from P-ECU 300, SMR 32 is in a conductive state in which main battery 28 and boost converter 20 are electrically connected and in a disconnected state in which main battery 28 and boost converter 20 are electrically disconnected. Switch from one of the states to the other.

  Boost converter 20 is connected to first power line MPL and first ground line MNL. Boost converter 20 performs voltage conversion between main battery 28, first power line MPL, and first ground line MNL based on the boost converter drive signal from MG-ECU 200.

  MG-ECU 200 receives boost converter information from boost converter 20. Boost converter information includes, for example, at least one of boost converter temperature, voltage and current on inverter 18 side, voltage and current on main battery 28 side, and current flowing through reactor 44. The boost converter 20 is provided with various sensors (not shown) for acquiring the above-described boost converter information.

  The MG-ECU 200 starts the engine 402 by using the boost converter information from the boost converter 20 and the state of the electrical equipment mounted on the vehicle 10 (for example, the state where the A / C compressor 102 starts to operate or the first MG 12). The target voltage is set based on the state and the like, and the boost converter 20 is controlled so that the voltage of the main battery 28 changes to the target voltage. The target voltage may be set as zero boost, for example.

  Boost converter 20 includes switching elements Q 1 and Q 2, diodes D 1 and D 2, and a reactor 44. Switching elements Q1, Q2 are connected in series between first power line MPL and first ground line MNL. As the switching elements Q1 and Q2, for example, power semiconductor switching elements such as IGBTs (Insulated Gate Bipolar Transistors), power MOS (Metal Oxide Semiconductor) transistors, or power bipolar transistors are used.

  The reactor 44 includes an annular core part and a coil wound around the outer periphery of the core part. One end of the coil of the reactor 44 is connected to the positive terminal of the main battery 28 via the first power line MPL. The other end of the coil of reactor 44 is connected to a connection node between switching element Q1 and switching element Q2.

  The diode D1 is connected in antiparallel to the switching element Q1. That is, the diode D1 is connected in parallel to the switching element Q1 with the direction toward the first power line MPL as the forward direction.

  The diode D2 is connected in antiparallel to the switching element Q2. That is, the diode D2 is connected in parallel to the switching element Q2 with the direction toward the reactor 44 as the forward direction.

  Based on the boost converter drive signal (duty signal) from MG-ECU 200, switching elements Q1 and Q2 of boost converter 20 are in opposite states (ie, Q2 is off when Q1 is on, and Q2 is on when Q1 is off. ). The voltage between the first power line MPL and the first ground line MNL is equal to or higher than the output voltage of the main battery 28 by alternately repeating the Q1 on period (Q2 off period) and the Q2 on period (Q1 off period). Controlled.

  The first capacitor 24 is connected between the second power line PL and the second ground line NL, and reduces the AC component included in the DC voltage between the second power line PL and the second ground line NL. The second capacitor 36 is connected between the first power line MPL and the first ground line MNL, and reduces the power fluctuation component included in the first power line MPL and the first ground line MNL.

  DC / DC converter 22 charges auxiliary battery 100 using the power of main battery 28 based on a control signal from P-ECU 300. The positive electrode of DC / DC converter 22 is connected to second power line PL, and the negative electrode of DC / DC converter 22 is connected to second ground line NL. Similarly, the positive electrode of A / C compressor 102 is connected to second power line PL, and the negative electrode of A / C compressor 102 is connected to second ground line NL.

  In the vehicle having the above-described configuration, the P-ECU 300 calculates the vehicle required power Ps based on detection signals such as a vehicle speed sensor, an accelerator position sensor, and a brake pedal depression force sensor (none of which are shown) and a traveling situation. The torque command values of the first MG 12 and the second MG 14 are calculated based on the calculated vehicle required power Ps.

  The MG-ECU 200 detects the torque command value for the first MG 12 input from the P-ECU 300, the inverter information from the inverter 18, the detection result by the current detector 58 that detects the motor current (phase currents Iv, Iw) of the first MG 12, and the first result. The operation of the inverter 18 is controlled so that the first MG 12 outputs a torque according to the torque command value based on the detection result by the one resolver 50 and the like.

  Similarly, the MG-ECU 200 determines the second MG 14 based on the torque command value for the second MG 14 input from the P-ECU 300, the inverter information from the inverter 18, the motor current of the second MG 14, the detection result by the second resolver 52, and the like. Controls the operation of the inverter 18 so as to output torque according to the torque command value.

  The MG-ECU 200 generates an inverter drive signal for controlling the inverter 18 and outputs the generated inverter drive signal to the inverter 18.

  MG-ECU 200 calculates a torque command value Trqcom of first MG 12 based on vehicle request power Ps input from P-ECU 200, for example. The MG-ECU 200 generates a d-axis current command value Idcom and a q-axis current command value Iqcom according to a predetermined map stored in a memory or the like from the calculated torque command value Trqcom.

  MG-ECU 200 calculates d-axis voltage command value Vd and q-axis voltage command value Vq based on the generated d-axis current command value Idcom and q-axis current command value Iqcom, and calculates the calculated d-axis voltage command value Vd and Based on the q-axis voltage command value Vq and the rotation angle θ2 of the rotation axis of the second MG 14, coordinate conversion from two phases to three phases is performed to generate three-phase voltage command values Vu, Vv, Vw. MG-ECU 200 generates an inverter drive signal based on the generated three-phase voltage command values Vu, Vv, Vw. As a result, PWM control is executed in inverter 18 and torque according to torque command value Trqcom is output in first MG 14. When the MG-ECU 200 generates the d-axis current command value Idcom and the q-axis current command value Iqcom, or generates the three-phase voltage command value, the MG-ECU 200 detects the detection result (that is, the motor current Iu, Iv, Iw) is fed back.

  In order to appropriately perform the drive control of such a three-phase AC motor, it is necessary to determine the failure of the current sensor by detecting the current of the same phase using a plurality of current sensors. However, it is desirable to reduce the number of current sensors as much as possible from the viewpoint of reducing production costs.

  Therefore, in the present embodiment, MG-ECU 200 determines that each of second current sensor 62 and third current sensor 64 is normal based on the detection results of second current sensor 62 and third current sensor 64. When it is determined that the current is in the state, the difference between the amplitude Aw of the W-phase current Iw detected by the first current sensor 60 and the amplitude Av of the V-phase current Iv is the threshold A (0). The first current sensor 60 is characterized in that it is determined to be in an abnormal state when the value is larger than.

  In the present embodiment, the abnormal state of the sensor is, for example, a value lower than a value (lower limit value) lower by a predetermined value than the output value when the sensor is in a normal state due to failure, short circuit or disconnection. Or a value that exceeds a value (upper limit value) that is higher by a predetermined value than the output value when the sensor is in a normal state.

  FIG. 3 shows a functional block diagram of MG-ECU 200 mounted on vehicle 10 according to the present embodiment. MG-ECU 200 includes a first abnormality determination unit 202, an amplitude calculation unit 204, a second abnormality determination unit 206, and a substitute value calculation unit 208.

  The first abnormality determination unit 202 determines whether at least one of the second current sensor 62 and the third current sensor 64 is in an abnormal state. Specifically, the first abnormality determination unit 202 does not match the detection value Iv1 of the current Iv detected by the second current sensor 62 with the detection value Iv2 of the current Iv detected by the third current sensor 64. In this case, it is determined that at least one of the second current sensor 62 and the third current sensor 64 is in an abnormal state. The first abnormality determination unit 202 determines that the second current sensor 62 and the third current sensor 64 are in a normal state when the detection values Iv1 and Iv2 match.

  The first abnormality determination unit 202 determines the detection values Iv1 and Iv2 when the magnitude of the difference between the detection values Iv1 and Iv2 of the current Iv, that is, | Iv1−Iv2 | is larger than the threshold value Iv (0). Are determined not to match. Further, the first abnormality determination unit 202 determines that the detected values Iv1 and Iv2 match the gAT when | Iv1-Iv2 | is equal to or less than the threshold value Iv (0). The threshold value Iv (0) is a statistical value based on, for example, sensor characteristics, an input mode from the sensor to the MG-ECU 200, a predicted value of | Iv1-Iv2 | To be determined.

  The first abnormality determination unit 202 turns on the first abnormality determination flag when determining that at least one of the second current sensor 62 and the third current sensor 64 is in an abnormal state, for example. You may do it.

  When the first abnormality determination unit 202 determines that the second current sensor 62 and the third current sensor 64 are in the normal state, the amplitude calculation unit 204 determines the amplitude Aw of the W-phase current Iw and the V-phase current sensor Iw. The amplitude Av of the current Iv is calculated. The amplitude calculation unit 204 measures the maximum value Iwmax and the minimum value Iwmin in a predetermined cycle of the current Iw detected by the first current sensor 60. The amplitude calculation unit 204 calculates the amplitude Aw using an equation of Aw = (Iwmax−Iwmin) / 2 based on the measured Iwmax and the minimum value Iwmin.

  The amplitude calculation unit 204 measures the maximum value Ivmax and the minimum value Ivmin in a predetermined cycle of the detection value Iv1 of the current Iv detected by the second current sensor 62. The amplitude calculation unit 204 calculates the amplitude Av using the equation Av = (Ivmax−Ivmin) / 2 based on the measured maximum value Ivmax and minimum value Ivmin. For example, when the first abnormality determination flag is OFF, the amplitude calculation unit 204 may calculate the amplitude Aw of the W-phase current Iw and the amplitude Av of the V-phase current Iv. The amplitude calculation unit 204 may calculate the amplitude Av using the detection value Iv1 using the detection value Iv2 of the current Iv detected by the third current sensor 64. Further, the predetermined period may be one period or a plurality of periods.

  The second abnormality determination unit 206 determines whether or not the first current sensor 60 is in an abnormal state. Specifically, the second abnormality determination unit 206 determines that the first current sensor 60 is in a normal state when the amplitude Aw calculated by the amplitude calculation unit 204 matches the amplitude Av. The second abnormality determination unit 206 determines that the first current sensor 60 is in an abnormal state when the calculated amplitude Aw and the amplitude Av do not match.

  The second abnormality determination unit 206 determines that the amplitude Aw and the amplitude Av match when the magnitude of the difference between the amplitude Aw and the amplitude Av, that is, when | Aw−Av | is equal to or less than the threshold value A (0). . The second abnormality determination unit 206 determines that the amplitude Aw and the amplitude Av do not match when | Aw−Av | is larger than the threshold value A (0). For example, the second abnormality determination unit 206 may turn on the second abnormality determination flag when it is determined that the first current sensor 60 is in an abnormal state. The threshold value A (0) is statistically determined based on the characteristics of the sensor, the mode of input from the sensor to the MG-ECU 200, and the predicted value of | Aw−Av | when the sensor partially fails. Is done.

  The substitute value calculation unit 208 calculates a substitute value of the current Iw when the second abnormality determination unit 206 determines that the first current sensor 60 is in an abnormal state. Specifically, the substitute value calculation unit 208 calculates a predicted waveform of the current Iw by shifting the current waveform of the current Iv obtained based on the detection value Iv1 detected by the second current sensor 62 by 120 °. For example, when the current waveform of the V-phase current Iv is described by an expression of Iv = Av × sin ωt, the current waveform of the W-phase current Iw is described by an expression of Iw = Aw × sin (ωt + 2π / 3). . Here, “ωt” is the electrical angle of the V phase. “Ω” is an angular velocity, “t” is time, and “Av” is a peak value (amplitude) of the V-phase current.

  The substitute value calculation unit 208 calculates a predicted value of the current Iw from the calculated predicted waveform of the current Iw. The substitute value calculation unit 208 determines the calculated predicted value as a substitute value of the W-phase current Iw.

  The substitute value calculation unit 208 may calculate the predicted waveform of the current Iw by shifting the phase of the current waveform of the current Iv based on the detection value Iv2 detected by the third current sensor 64 by 120 °.

  Further, the substitute value calculation unit 208 may calculate a substitute value of the current Iw, for example, when the second abnormality determination flag is turned on.

  In the present embodiment, all of first abnormality determination unit 202, amplitude calculation unit 204, second abnormality determination unit 206, and substitute value calculation unit 208 are programs in which the CPU of MG-ECU 200 is stored in memory. However, it may be realized by hardware. Such a program is recorded on a storage medium and mounted on the vehicle.

  With reference to FIG. 4, a control structure of a program executed by MG-ECU 200 mounted on vehicle 10 according to the present embodiment will be described. In the flowchart, the Iw sensor means the first current sensor 60, and the Iv sensor means the second current sensor 62 and the third current sensor 64.

  In step (hereinafter referred to as S) 100, MG-ECU 200 determines whether Iv1 and Iv2 match. If Iv1 and Iv2 match (YES in S100), the process proceeds to S102. If not (NO in S100). The process proceeds to S104.

  In S102, MG-ECU 200 uses first current sensor 60 to measure maximum value Iwmax and minimum value Iwmin in a predetermined cycle of current Iw. Furthermore, MG-ECU 200 measures maximum value Ivmax and minimum value Ivmin in a predetermined cycle of current Iv using second current sensor 62.

  In S104, MG-ECU 200 determines that at least one of second current sensor 62 and third current sensor 64 is in an abnormal state.

  In S106, MG-ECU 200 calculates amplitude Aw based on measured maximum value Iwmax and minimum value Iwmin. Furthermore, MG-ECU 200 calculates amplitude Av based on measured maximum value Ivmax and minimum value Ivmin.

  In S108, MG-ECU 200 determines whether or not amplitude Av of current Iv matches amplitude Aw of current Iw. Since the method for determining whether or not the amplitude Av and the amplitude Aw match is as described above, detailed description thereof will not be repeated. If amplitude Av and amplitude Aw match (YES in S108), the process proceeds to S110. If not (NO in S108), the process proceeds to S112.

  In S110, MG-ECU 200 determines that first current sensor 60, second current sensor 62, and third current sensor 64 are all in a normal state. In S112, MG-ECU 200 determines that first current sensor 60 is in an abnormal state and second current sensor 62 and third current sensor 64 are in a normal state.

  In S114, MG-ECU 200 selects the failsafe mode of vehicle 10. When the fail safe mode of the vehicle 10 is selected, the MG-ECU 200 sets, for example, the upper limit value of the vehicle speed of the vehicle 10 to a value lower than the normal value.

  In S116, MG-ECU 200 calculates a substitute value for current Iw. Since the method for calculating the substitute value of current Iw is as described above, detailed description thereof will not be repeated.

  The operation of MG-ECU 200 mounted on vehicle 10 according to the present embodiment based on the above-described structure and flowchart will be described with reference to FIG.

<When all current sensors are in normal condition>
The magnitude | Iv1−Iv2 | of the difference between the detection value Iv1 (thin solid line in FIG. 5) from the second current sensor 62 and the detection value Iv2 (dotted line in FIG. 5) from the third current sensor 64 is a threshold value. If Iv (0) or less, it is determined that detected values Iv1 and Iv2 match (YES in S100).

  Therefore, the maximum value Iwmax and the minimum value Iwmin in a predetermined cycle (t_w) of the current Iw (thick solid line in FIG. 5) detected by the first current sensor 60 are measured. Further, the maximum value Ivmax and the minimum value Ivmin in a predetermined cycle (t_v) of the current Iv (thin solid line in FIG. 5) detected by the second current sensor 62 are measured (S102). Then, the amplitude Aw is calculated based on the measured maximum value Iwmax and the minimum value Iwmin, and the amplitude Av is calculated based on the measured maximum values Ivmax and Ivmin (S106).

  When the difference between the calculated amplitude Av and amplitude Aw is | Av−Aw | is equal to or smaller than threshold value A (0), it is determined that amplitude Av and amplitude Aw match (YES in S108). . Therefore, it is determined that all current sensors are in a normal state (S110), and the control of the first MG 12 is continued.

<When only the first current sensor 60 is in an abnormal state>
For example, it is assumed that the current waveform of the current Iw becomes a waveform as shown by a two-dot chain line in FIG. At this time, if the difference | Av−Aw ′ | between the calculated amplitude Av and the amplitude Aw ′ is larger than the threshold value A (0), it is determined that the amplitude Av and the amplitude Aw ′ do not match (S108). NO). If the amplitude Av and the amplitude Aw ′ do not match, it is determined that the first current sensor 60 is in an abnormal state (S112). For this reason, the fail-safe mode of the vehicle is selected (S114), and a predicted waveform (FIG. 5) obtained by shifting the phase of the current waveform of the current Iv (thin solid line in FIG. 5) detected by the second current sensor 62 by 120 °. A substitute value of the current Iw is calculated from the waveform substantially matching the thick solid line (S116). MG-ECU 200 controls inverter 18 using detected value Iv1 and a substitute value for current Iw. Thus, even when it is determined that the first current sensor 60 is in an abnormal state, the control of the first MG 12 is continued.

<When the third current sensor 64 is in an abnormal state>
For example, it is assumed that the current waveform of the current Iv based on the detection value Iv2 becomes a waveform as shown by a broken line in FIG. 5 due to a failure of the third current sensor 64 or the like. At this time, when the magnitude | Iv1-Iv2 | of the difference between the detection value Iv1 detected by the second current sensor 62 and the detection value Iv2 detected by the third current sensor 64 is larger than the threshold value Iv (0), the detection is performed. It is determined that values Iv1 and Iv2 do not match (NO in S100). Therefore, it is determined that one of the second current sensor 62 and the third current sensor 64 is in an abnormal state (S104). Even when the second current sensor 62 is in an abnormal state, the same processing as that in the case where the third current sensor 64 is in an abnormal state is performed. Therefore, detailed description thereof will not be repeated.

  In the present embodiment, in particular, at least one of the first current sensor 60, the second current sensor 62, and the third current sensor 64 included in the current detection device 58 that detects the motor current of the first MG 12. Although it has been described that it is determined whether any one is in an abnormal state, the current sensor included in the current detection device that detects the motor current of the second MG 14 is similarly determined whether it is in an abnormal state. . Therefore, since the determination method is the same, detailed description thereof will not be repeated.

  As described above, according to the vehicle according to the present embodiment, at least one of the second current sensor 62 and the third current sensor 64 depends on whether or not the detection values Iv1 and Iv2 match. It is possible to determine with high accuracy whether or not the state is abnormal. Further, when it is determined that the second current sensor 62 and the third current sensor 64 are in the normal state, the amplitude Aw of the current Iw detected by the first current sensor 60 and the second current sensor 62 Whether or not the first current sensor 60 is in an abnormal state can be determined with high accuracy depending on whether or not the amplitude Av of the detected current Iv matches. In addition, since it is possible to determine whether or not each current sensor is in an abnormal state using three current sensors, a total of four current sensors, two for each phase, and two for each phase. The number of current sensors can be reduced as compared with the case where an abnormality is detected by comparing output values between the sensors. Therefore, it is possible to provide an abnormality determination method for a vehicle and a current detection device that can easily detect a failure of the current sensor and suppress an increase in production cost.

  In the present embodiment, it has been described that it is determined whether or not the first current sensor 60 is in an abnormal state based on the magnitude of the difference between the amplitude Aw and the amplitude Av, but for example, the amplitude Aw and the amplitude Av In addition to the magnitude of the difference between the current Iv and the current Iw, it may be determined whether or not the first current sensor 60 is in an abnormal state.

  For example, the MG-ECU 200 determines whether the phase difference between the current Iv and the current Iw is not 120 ° or the phase difference between the current Iv and the current Iw is about 120 ° even when the amplitude Aw and the amplitude Av match. If not within the range, the first current sensor 60 may be determined to be in an abnormal state.

  In the present embodiment, MG-ECU 200 determines that second current sensor 62 and third current sensor 64 are in a normal state because detection values Iv1 and Iv2 match. In the above description, the first current sensor 60 is determined to be in a normal state or an abnormal state based on the amplitude Aw and the amplitude Av based on the detection value Iv1 of the second current sensor 62. However, the amplitude Av is Alternatively, the average value of the detection values Iv1 and Iv2 may be used.

  Furthermore, in the present embodiment, MG-ECU 200 determines that second current sensor 62 and third current sensor 64 are in a normal state because detection values Iv1 and Iv2 match. The first current sensor 60 has been described as determining whether it is in a normal state or an abnormal state based on the amplitude Aw and the amplitude Av. In particular, whether the first to third current sensors are in a normal state. The method for determining whether the state is abnormal is not limited to this.

  For example, the MG-ECU 200 determines that the first current sensor and the second current sensor 62 are in a normal state when the amplitude Aw and the amplitude Av based on the detection value Iv1 of the second current sensor 62 match. . Further, when it is determined that the first current sensor 60 and the second current sensor 62 are in the normal state, the MG-ECU 200 determines that the amplitude Av based on the amplitude Aw and the detection value Iv2 of the third current sensor 64 is If they match, the third current sensor 64 may be determined to be in a normal state. Alternatively, when it is determined that the first current sensor 60 and the second current sensor 62 are in the normal state, the MG-ECU 200 determines that the third current sensor 64 matches the detected values Iv1 and Iv2. May be determined to be in a normal state.

  Alternatively, MG-ECU 200 determines that first current sensor 60 and third current sensor 64 are in a normal state when amplitude Aw and amplitude Av based on detection value Iv2 of third current sensor 64 match. To do. Further, when it is determined that the first current sensor 60 and the third current sensor 64 are in the normal state, the MG-ECU 200 determines that the amplitude Av based on the amplitude Aw and the detection value Iv1 of the second current sensor 62 is If it is determined that the second current sensor 62 is in a normal state, the second current sensor 62 may be determined to be normal. Alternatively, when it is determined that the first current sensor 60 and the third current sensor 64 are in the normal state, the MG-ECU 200 determines that the second current sensor 62 is equal to the detected value Iv1 and Iv2. May be determined to be in a normal state.

  Furthermore, when the detection values Iv1 and Iv2 do not match, the MG-ECU 200 determines whether or not the amplitude Aw and the amplitude Av based on the detection value Iv1 match, and the amplitude based on the amplitude Aw and the detection value Iv2 You may make it determine whether Av corresponds. In this way, for example, when the amplitude Aw and the amplitude Av based on the detection value Iv1 match, and the amplitude Av based on the detection value Iv2 does not match, the MG-ECU 200 detects that the third current sensor is abnormal. It can be determined that it is in a state. Further, for example, when the amplitude Aw and the amplitude Av based on the detection value Iv1 do not match, and the amplitude Av based on the detection value Iv2 matches, the MG-ECU 200 determines that the second current sensor 62 is in an abnormal state. It can be determined that

  In the present embodiment, the operation of the vehicle 10 is controlled using three ECUs of MG-ECU 200, P-ECU 300, and engine ECU 400, but the functions of the three ECUs are integrated. You may make it control operation | movement of the vehicle 10 using one ECU (For example, ECU enclosed with the frame of the dashed-dotted line of FIG. 1 is an example).

  In the present embodiment, vehicle 10 may be a front wheel drive vehicle or a rear wheel drive vehicle. The vehicle 10 may be a vehicle equipped with a rear motor that drives the rear wheels in addition to the configuration shown in FIG. Moreover, although the vehicle 10 was demonstrated as a hybrid vehicle, it is not limited to the hybrid vehicle of the format shown in FIG. For example, vehicle 10 may be a parallel hybrid vehicle including, for example, engine 402 and a drive motor generator directly connected to a crankshaft of engine 402. Alternatively, the vehicle 10 may be a vehicle in which front wheels are driven by an engine and rear wheels are driven by an electric motor.

  Moreover, the vehicle 10 should just be a vehicle which used the three-phase alternating current motor as a drive source, for example, may be an electric vehicle. As an electric vehicle, an electric motor may be provided on the vehicle body side, or an electric motor may be provided on the wheel side.

  Furthermore, in the present embodiment, when detecting a W-phase current using one current sensor and detecting a V-phase current using two current sensors, the two current sensors Arranged in series along the phase power cable. Therefore, the three current sensors can be arranged more compactly than the case where the three current sensors are provided in the power cables of the respective phases.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  10 vehicle, 18 inverter, 20 boost converter, 22 DC / DC converter, 24 first capacitor, 28 main battery, 36 second capacitor, 38 discharge resistance, 44 reactor, 50 first resolver, 52 second resolver, 58 current detection Apparatus, 60 first current sensor, 62 second current sensor, 64 third current sensor, 100 auxiliary battery, 102 A / C compressor, 200 MG-ECU, 202 first abnormality determination unit, 204 amplitude calculation unit 206, second abnormality determination unit, 208 substitute value calculation unit, 300 P-ECU, 400 engine ECU, 404 power split device, 406 drive wheel, 408 transmission.

Claims (5)

A three-phase AC motor,
A first current sensor for detecting a first current flowing in a first phase of the three phases;
Second and third current sensors for detecting a current flowing in a second phase different from the first phase;
A control unit for receiving a detection result from each of the first to third current sensors and controlling the three-phase AC motor;
The second current sensor has a higher resolution than the third current sensor;
When the control unit determines that the second and third current sensors are in a normal state based on the detection results of the second and third current sensors, the detection result of the first current sensor The first amplitude of the first phase current based on the second phase current and the second amplitude of the second phase current based on the detection result of the second current sensor is A vehicle that determines that the first current sensor is in an abnormal state when greater than a threshold value of 1.   The control unit is configured such that the magnitude of the second difference between the first detection value of the second current sensor and the second detection value of the third current sensor is smaller than a second threshold value. The vehicle according to claim 1, wherein the second and third current sensors are determined to be in the normal state.   The vehicle according to claim 1, wherein the control unit determines that the first current sensor is in a normal state when the magnitude of the first difference is smaller than the first threshold value. . A three-phase AC motor,
A first current sensor for detecting a first current flowing in a first phase of the three phases;
Second and third current sensors for detecting a current flowing in a second phase different from the first phase;
A control unit for receiving a detection result from each of the first to third current sensors and controlling the three-phase AC motor;
The second current sensor has a higher resolution than the third current sensor;
When the control unit determines that the first and second current sensors are in a normal state based on the detection results of the first and second current sensors, the detection result of the second current sensor a first amplitude of the current of the second phase based on, is greater than a threshold magnitude of the difference between the second amplitude of the second phase of the current based on a detection result of the third current sensor And determining that the third current sensor is in an abnormal state. A first current sensor for detecting a current flowing in a first phase of the three phases of the three-phase AC motor; a second for detecting a current of a second phase different from the first phase; An abnormality determination method for determining an abnormality of a current detection device including a third current sensor, wherein the second current sensor has a higher resolution than the third current sensor,
Detecting the current of the first phase using the first current sensor;
Detecting the current of the second phase using the second and third current sensors;
When it is determined that the second and third current sensors are normal based on the detection results of the second and third current sensors, the first based on the detection results of the first current sensor The first amplitude when the magnitude of the difference between the first amplitude of the phase current and the second amplitude of the second phase current based on the detection result of the second current sensor is greater than a threshold value. An abnormality determination method for a current detection device, wherein the current sensor is determined to be in an abnormal state.

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