JP2006081341A - Fault determination device in loading drive circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To determine an abnormal sensor by applying discharge processing if a deviation occurs between detected voltages of two voltage sensors. <P>SOLUTION: An ECU executes a program including a step (S100) of detecting a battery voltage VB with a VB sensor; a step (S110) of detecting an inverter voltage VH with the VH sensor; a step (S120) of calculating an absolute value ΔV of a difference between them; a step (S140) of limiting vehicle running if a large ΔV continues for a long period (YES in S130); and a step (S200) of detecting an inverter voltage with the VH sensor after discharge processing (S170), and determining the VH sensor to be failed unless the inverter voltage is not VH≈0 (NO in S180). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an apparatus for determining an abnormality of a load drive circuit, and more particularly to an abnormality determination apparatus for a load drive circuit that determines an abnormality of a sensor included in the load drive circuit.

  2. Description of the Related Art In recent years, attention has been paid to vehicles that run with a driving force from a motor, such as a hybrid vehicle, a fuel cell vehicle, and an electric vehicle, as part of measures for environmental problems. Such a vehicle is equipped with a battery for storing electric power to be supplied to the motor. The motor is connected to the inverter, and the inverter is connected to the battery. A motor (including a motor generator) and an inverter serve as loads for the battery. A circuit including such a battery, an inverter, and a motor is referred to as a load drive circuit.

  In such a load driving circuit, a voltage sensor for detecting an input voltage of the inverter and an output voltage of the battery is provided, and the load driving circuit is controlled based on the voltages detected by these sensors. For example, in a load drive circuit that is mounted on a hybrid vehicle and transmits part of the engine torque to the motor generator and the rest to the drive wheels, the battery voltage is high, for example, when traveling on a long downhill road. Then, when the motor generator is driven as a generator, the load applied to the inverter becomes large. Therefore, the generator torque is limited when the battery voltage is high.

  In such a hybrid vehicle load drive device, if an abnormality occurs in the battery voltage sensor, the battery voltage cannot be detected normally, and drive control cannot be performed smoothly. Japanese Patent Laying-Open No. 2003-47107 (Patent Document 1) discloses a hybrid vehicle drive control device capable of smoothly performing drive control when a voltage information detection abnormality occurs. The hybrid vehicle drive control device includes a generator that generates electric power by driving an engine, a generator inverter for driving the generator, a drive motor that drives the hybrid vehicle, and a drive motor that drives the drive motor. A drive motor inverter, a battery connected to the generator inverter and the drive motor inverter, a first voltage sensor for detecting a voltage applied to the generator inverter, and a voltage applied to the drive motor inverter A second voltage sensor for detecting the battery voltage, a third voltage sensor for detecting the battery voltage, and a system voltage determination processing unit for determining a system voltage based on detection results of the first to third voltage sensors.

According to this hybrid vehicle drive control device, the system voltage can be determined based on the difference between two detection results among the detection results of the first to third voltage sensors.
JP 2003-47107 A

  However, in the hybrid vehicle drive control device disclosed in Patent Document 1 described above, the difference between the three voltage sensors is calculated based on the detection results by the three voltage sensors, and the system voltage is calculated using them. Judgment. For this reason, three voltage sensors are required, and this is not applicable when there are only two voltage sensors. That is, in a load drive circuit having a voltage sensor that detects a battery voltage and a voltage sensor that detects an inverter voltage, if there is a difference between the voltage values detected by these voltage sensors, it cannot be determined which one has failed. .

  On the other hand, in such a load drive circuit, when an AC motor is driven by a battery that is a DC power supply, a power converter that converts the DC power supplied from the battery into an AC power supply is required. An inverter is used. A smoothing capacitor for smoothing the output of the DC power supply is provided on the input side of the inverter, that is, on the DC power supply side.

  The smoothing capacitor is constantly charged and discharged during motor operation. For this reason, after the operation of the motor is terminated, for example, even after the ignition switch is turned off, the charge is often stored in the smoothing capacitor. It is desirable that no charge is stored in the smoothing capacitor. Therefore, in order to discharge the electric charge accumulated in the smoothing capacitor, after the ignition switch is turned off, a discharge process (discharge process) is performed in which the inverter is driven for a certain period of time to discharge the electric charge to the motor side. ing.

  The present invention has been made in order to solve the above-described problems. The object of the present invention is to apply an electrical discharge process (discharge process) to detect an abnormal sensor when a deviation occurs between two voltages. An object of the present invention is to provide an abnormality determination device in a load drive circuit that can be determined.

  An abnormality determination device in a load drive circuit according to a first invention determines an abnormality in a load drive circuit including a power storage device and a load circuit that transmits and receives power between the power storage devices. The abnormality determination device includes a first detection unit for detecting a voltage value of the power storage device, a second detection unit for detecting a voltage value on the input side of the load circuit, and the detected voltage of the power storage device. Calculating means for calculating a difference value between the value and the voltage value of the load circuit, monitoring means for monitoring abnormality of the detecting means based on the difference value and a predetermined threshold value, and detecting means Is detected based on the voltage value of the load circuit by the second detection means in correspondence with the discharge process of the storage element provided on the input side of the load circuit. Determination means for determining.

  According to the first invention, when the load driving circuit is in a steady state, the voltage value of the power storage device and the voltage value on the input side of the load circuit are substantially the same. However, if either one of the first detection means and the second detection means fails or both of them fail, a difference value between the voltage value of the power storage device and the voltage value of the load circuit is determined in advance. The threshold is exceeded. In such a case, the determination unit determines which detection unit has an abnormality. At this time, when the discharge process of the storage element of the load circuit is completed, the voltage value of the load circuit should be substantially zero if the second detection means is normal, but otherwise It can be determined that the second detection means is abnormal. As a result, it is possible to provide an abnormality determination device in a load drive circuit that can determine an abnormal sensor by applying this discharge process when a deviation occurs between two voltages.

  In the abnormality determination device according to the second invention, in addition to the configuration of the first invention, the monitoring means monitors the abnormality of the detection means depending on whether or not the difference value is equal to or greater than a predetermined threshold value. Means for doing so.

  According to the second invention, when the difference value between the voltage value of the power storage device and the voltage value of the load circuit is equal to or greater than a predetermined threshold value, at least one of the first detection means and the second detection means It can be determined that there is a possibility of abnormality.

  In the abnormality determination device according to the third aspect of the invention, in addition to the configuration of the first aspect, the monitoring means has a time when the difference value is equal to or greater than a predetermined threshold value being equal to or greater than a predetermined time. It includes means for monitoring the abnormality of the detecting means depending on whether or not.

  According to the third aspect of the invention, the difference value between the voltage value of the power storage device and the voltage value of the load circuit is equal to or greater than a predetermined threshold value (may be a duration or an integration time). If it is long, it can be determined that there is a higher possibility that at least one of the first detection means and the second detection means is abnormal.

  In the abnormality determination device according to the fourth invention, in addition to the configuration of the first invention, the monitoring means continues the time when the difference value is equal to or greater than a predetermined threshold value for a predetermined time or more. Means for monitoring the abnormality of the detection means is included depending on whether or not it is present.

  According to the fourth invention, if the time during which the difference value is equal to or greater than the predetermined threshold is continuously long, there is a possibility that at least one of the first detection means and the second detection means is abnormal. It can be judged that it is higher.

  In the abnormality determination device according to the fifth invention, in addition to the configuration of any one of the first to fourth inventions, the determination means has a voltage value of the load circuit by the second detection means of approximately 0 after the discharge process. Means for determining an abnormal detection means based on whether or not there is.

  According to the fifth invention, after the discharge process, the voltage value of the load circuit should be substantially zero. Therefore, when the second detection means is normal, the detected voltage value should be substantially zero. It is. Nevertheless, if the voltage value detected by the second detection means is not substantially 0, it can be determined that there is a high possibility that the second detection means is abnormal.

  In the abnormality determination device according to the sixth invention, in addition to the configuration of any one of the first to fourth inventions, the determination means has a voltage value of the load circuit by the second detection means of substantially 0 after the discharge process. If there is, means for determining that the first detection means is abnormal is included.

  According to the sixth invention, after the discharge process, the voltage value of the load circuit should be substantially zero. Therefore, when the second detection means is normal, the detected voltage value should be substantially zero. It is. If the voltage value detected by the second detection means is substantially 0, it can be determined that the second detection means is normal and the first detection means is likely to be abnormal.

  In the abnormality determination device according to the seventh invention, in addition to the configuration of any one of the first to fourth inventions, the determination means has a voltage value of the load circuit by the second detection means that is not substantially zero after the discharge process. And means for determining that the second detection means is abnormal.

  According to the seventh invention, after the discharge process, the voltage value of the load circuit should be substantially zero. Therefore, when the second detection means is normal, the detected voltage value should be substantially zero. It is. If the voltage value detected by the second detection means is not substantially 0, it can be determined that the second detection means is abnormal and the first detection means is likely to be normal.

  In the abnormality determination device according to the eighth invention, in addition to the configuration of any one of the first to seventh inventions, the power storage device is a battery, the load circuit is an inverter, and the power storage element is a smoothing capacitor of the inverter. It is.

  According to the eighth aspect of the present invention, any abnormality of the voltage sensor that measures the voltage of the battery and the voltage sensor that measures the input voltage of the inverter can be determined using the discharge process of the smoothing capacitor.

  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.

  With reference to FIG. 1, a vehicle equipped with an abnormality determination device according to an embodiment of the present invention will be described. This vehicle includes a battery 100, an inverter 200, a traveling motor 300, a capacitor 400, an SMR (1) 500, a limiting resistor 502, an SMR (2) 504, an SMR (3) 506, an ECU ( Electronic Control Unit) 600. The abnormality determination device according to the present embodiment is realized by a program executed by ECU 600. In the present embodiment, the vehicle will be described as an electric vehicle that travels only by the driving force from the traveling motor 300, but the vehicle on which the abnormality determination device in the load drive circuit according to the present invention is mounted is not limited to an electric vehicle. Alternatively, it may be mounted on a hybrid vehicle, a fuel cell vehicle, or the like.

  The battery 100 is an assembled battery in which a plurality of modules in which a plurality of cells are connected in series are further connected in series. A capacitor may be used instead of the battery 100.

  Inverter 200 includes six IGBTs (Insulated Gate Bipolar Transistors) and six diodes connected in parallel to each IGBT so that current flows from the emitter side to the collector side of the IGBT. The inverter 200 converts the current supplied from the battery 100 from an alternating current to a direct current by turning on / off (energizing / cutting off) the gate of each IGBT based on a control signal from the ECU 600. 300. Inverter 200 and IGBT may use a well-known technique, and therefore, detailed description thereof will not be repeated here.

  Traveling motor 300 is a three-phase AC motor. The rotation shaft of the traveling motor 300 is finally connected to a drive shaft (not shown) of the vehicle. The vehicle travels by the driving force from the travel motor 300.

  The capacitor 400 is connected in parallel with the inverter 200. Capacitor 400 temporarily stores electric charge in order to smooth the power supplied from battery 100 or the power supplied from inverter 200. The smoothed power is supplied to the inverter 200 or the battery 100.

  SMR (1) 500 and SMR (2) 504 are provided on the positive electrode side of battery 100. SMR (1) 500 and SMR (2) 504 are connected in parallel. A limiting resistor 502 is connected to the SMR (1) 500 in series. SMR (1) 500 is a precharge SMR that is connected before SMR (2) 504 is connected and prevents an inrush current from flowing through inverter 200. SMR (2) 504 is a positive SMR connected after SMR (1) 500 is connected and precharge is completed. SMR (3) 506 is a negative SMR provided on the negative electrode side of battery 100. Each SMR is controlled by ECU 600.

  ECU 600 executes a program stored in a ROM (Read Only Memory) based on the amount of depression of an ignition switch (not shown), an accelerator pedal (not shown), the amount of depression of a brake pedal (not shown), etc. Then, the inverter 200 and each SMR are controlled to drive the vehicle in a desired state. ECU 600 is connected to a VH sensor 602 that detects the voltage of capacitor 400. By detecting the voltage of the capacitor 400, the voltage VH of the inverter 200 (travel motor 300) is detected. Furthermore, a VB sensor 604 that detects the voltage VB of the battery 100 is connected to the ECU 600.

  SMR (1) 500, SMR (2) 504, and SMR (3) 506 are relays that close contacts that are turned on when an exciting current is applied to the coil. The relationship between the operation state of SMR (1) 500, SMR (2) 504, and SMR (3) 506 and the position of the ignition switch will be described. The ignition switch has an OFF (off) position, an ACC position, an ON (on) position, and a STA (start) position. When the power is shut down, that is, when the position of the ignition switch is in the OFF position, SMR (1) 500, SMR (2) 504, and SMR (3) 506 are turned off. That is, the excitation current for the coils of each SMR (1) 500, SMR (2) 504, and SMR (3) 506 is turned off. The ignition switch position is switched in the order of OFF position → ACC position → ON position → STA position, and automatically returns from the STA position to the ON position.

  When the power is connected, that is, when the ignition switch position is switched from the OFF position to the STA position via the ACC position and the ON position, ECU 600 first turns on SMR (3) 506 and then turns on SMR (1) 500. Then, precharge is executed. Since the limiting resistor 502 is connected to the SMR (1) 500, the inverter voltage VH rises gently even when the SMR (1) 500 is turned on, and the occurrence of an inrush current can be prevented. Note that, when a discharge process is performed such as when the ignition switch position is switched from the ON position to the OFF position, an abnormality determination process described later is executed. The abnormality determination process may be performed separately from the operation of the ignition switch, and may be performed when the discharge process is performed.

  ECU 600 completes the precharge when inverter voltage VH reaches about 80% of battery voltage VB, for example, and turns on SMR (2) 504. ECU 600 turns off SMR (1) 500 and turns on power from battery 100 when inverter voltage VH becomes substantially equal to battery voltage VB.

  On the other hand, when the position of the ignition switch is switched from the ON position to the OFF position, ECU 600 first turns off SMR (2) 504 and then turns off SMR (3) 506. As a result, the electrical connection between the battery 100 and the inverter 200 is cut off, and the power supply is cut off. At this time, the residual voltage on the drive circuit side is discharged, and the inverter voltage VH gradually converges to about 0 V (voltage at shut-off). Note that the cutoff voltage is not necessarily 0 V, and may be a weak voltage of about 2 or 3 V, for example.

  With reference to FIG. 2, a control structure of a program executed by ECU 600 in order to realize the abnormality determination device in the load drive circuit according to the present embodiment will be described.

  In step (hereinafter, step is abbreviated as S) 100, ECU 600 detects battery voltage VB by VB sensor 604. In S110, ECU 600 detects inverter voltage VH by VH sensor 602. In S120, ECU 600 calculates an absolute value ΔV (= | VB−VH |) of a difference between battery voltage VB and inverter voltage VH.

  In S130, ECU 600 determines whether or not the time during which absolute value ΔV of the difference between battery voltage VB and inverter voltage VH is equal to or greater than a threshold value continues for a predetermined time or more. If the time during which absolute value ΔV of the voltage difference is equal to or greater than the threshold value continues for a predetermined time or longer (YES in S130), the process proceeds to S140, that is, in the steady state, the battery voltage VB and inverter voltage VH must be approximately equal. If the difference (deviation) between the battery voltage VB and the inverter voltage VH is large, it is considered that one of the voltage sensors is out of order, so the processing from S140 is performed. Otherwise (NO at S130), this process ends.

  In S140, ECU 600 executes a limiting process due to the abnormality of the voltage sensor. As the restriction process, the following process can be considered. For example, when it is determined that the absolute value ΔV of the difference between the battery voltage VB and the inverter voltage VH does not cause a significant hindrance to the traveling control, the traveling is continued while limiting the charging of the battery, for example. Further, when it is determined that the absolute value ΔV of the difference between the battery voltage VB and the inverter voltage VH has a high possibility of causing a great trouble in the running control, for example, a process for stopping the running of the vehicle is performed. To do. At this time, SMR (1) 500, SMR (2) 504 and SMR (3) 506 are forcibly turned off.

  In S150, ECU 600 determines whether SMR (1) 500, SMR (2) 504, and SMR (3) 506 have been turned off. If SMR is turned off (YES in S150), the process proceeds to S160. If not (NO in S150), the process returns to S150 and waits until SMR is turned off. When the SMR is turned off, even when the ECU 600 is forcibly turned off, the ECU 600 determines that the driver has turned the ignition switch to the OFF position after seeing the warning of the voltage sensor abnormality displayed on the instrument panel. This includes cases where it is turned off by the other cases.

  In S160, ECU 600 performs a discharge process for driving inverter 200 for a certain period of time or more to discharge the electric charge of smoothing capacitor 400 to the motor 300 side.

  In S170, ECU 600 detects inverter voltage VH by VH sensor 602. In S180, ECU 600 determines whether or not inverter voltage VH is substantially 0 [V]. If inverter voltage VH is approximately 0 [V] (YES in S180), the process proceeds to S190. If not (NO in S180), the process proceeds to S200. That is, when the discharge process is completed, the inverter voltage VH should be almost 0 [V]. Nevertheless, the fact that the inverter voltage VH detected by the VH sensor 602 is not substantially 0 [V] indicates that there is a high possibility that the VH sensor 602 is abnormal.

  In S190, ECU 600 executes VB sensor abnormality determination processing that determines that there is a high possibility that VB sensor 604 is abnormal. In S200, ECU 600 executes VB sensor abnormality determination processing that determines that there is a high possibility that VH sensor 602 is abnormal. Such an abnormality confirmation result is stored in a diagnosis code. Further, an abnormality warning may be displayed on the instrument panel to notify the driver.

  An operation of ECU 600 that is an abnormality determination device in the load drive circuit according to the present embodiment based on the above-described structure and flowchart will be described.

  While the vehicle is operating using the motor 300, the load drive circuit is in a steady state (a state that is not a precharge state or a discharge state), and the VB sensor 604 detects that the VB sensor 604 and the VH sensor 602 are normal. There is no difference between the voltage of the battery 100 and the inverter voltage VH detected by the VH sensor 602.

  The battery voltage is detected by the VB sensor 604 (S100), the inverter voltage is detected by the VH sensor 602 (S110), the difference value ΔV that is the absolute value of the difference is calculated (S120), and the difference value ΔV Is continuously longer than the threshold value (YES in S130), VB sensor 604 and / or VH sensor 602 are regarded as not normal, and restriction processing is performed (S140).

  When SMR is turned off (YES in S150) and smoothing capacitor 400 is discharged (S160), inverter voltage VH after the discharge process should be approximately 0 [V]. However, if inverter voltage VH detected by inverter voltage sensor 602 is not substantially 0 (NO in S180), it is determined that inverter voltage sensor 602 is abnormal (S200). On the other hand, when inverter voltage VH detected by inverter voltage sensor 602 is substantially 0 (YES in S180), it is determined that battery voltage sensor 604 is abnormal (S190).

  As described above, in the ECU that is an abnormality determination device in the load drive circuit according to the present embodiment, when the load drive circuit is in a steady state, the voltage value of the battery and the voltage value on the input side of the inverter are approximately Be the same. However, if either one of the battery voltage sensor and the inverter voltage sensor fails or both of them fail, the difference value between the battery voltage value and the inverter voltage value becomes equal to or greater than a predetermined threshold value. . In such a case, when the discharge process of the smoothing capacitor is finished, if the inverter voltage sensor is normal, the detected inverter voltage value should be almost zero, but if not, the inverter voltage sensor is normal. It can be determined that the voltage sensor is abnormal. As a result, when a deviation occurs between the two voltages, an abnormal sensor can be determined by applying this discharge process.

  In the flowchart of FIG. 2, when the battery voltage sensor 604 and the inverter voltage sensor VH are in a state showing substantially the same voltage, the absolute value ΔV of the difference between the battery voltage VB and the inverter voltage VH is constantly monitored, When this becomes smaller than the threshold value, the processing represented by this flowchart may be interrupted.

  Further, the determination process of S130 in the flowchart of FIG. 2 may be a condition of ΔV ≧ threshold only. Further, it may be determined whether or not the integrated value of the time when the absolute value ΔV of the difference between the battery voltage VB and the inverter voltage VH is equal to or greater than a threshold value is equal to or greater than a predetermined time (ie, , Not subject to continuation).

  Furthermore, even when the load drive circuit includes a DC / DC converter, the present invention can be applied.

  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.

1 is a diagram showing an overall configuration of a vehicle equipped with an abnormality determination device in a load drive circuit according to an embodiment of the present invention. It is a flowchart which shows the control structure of the abnormality determination program performed with ECU of FIG.

Explanation of symbols

  100 battery, 200 inverter, 300 travel motor, 400 capacitor, 500, 504, 506 SMR, 502 limiting resistance, 600 ECU, 602 VH sensor, 604 VB sensor.

Claims (8)

An abnormality determination device in a load drive circuit comprising a power storage device and a load circuit that transmits and receives power between the power storage device,
First detecting means for detecting a voltage value of the power storage device;
Second detection means for detecting a voltage value on the input side of the load circuit;
Calculating means for calculating a difference value between the detected voltage value of the power storage device and the voltage value of the load circuit;
Monitoring means for monitoring abnormality of the detection means based on the difference value and a predetermined threshold;
If it is determined that there is an abnormality in the detection means, the abnormality is detected based on the voltage value of the load circuit by the second detection means in correspondence with the discharge process of the storage element provided on the input side of the load circuit. And an abnormality determination device including determination means for determining the detection means.   The abnormality determination device according to claim 1, wherein the monitoring unit includes a unit for monitoring an abnormality of the detection unit based on whether or not the difference value is equal to or greater than a predetermined threshold value.   The monitoring means includes means for monitoring an abnormality of the detecting means depending on whether or not a time during which the difference value is equal to or greater than a predetermined threshold is equal to or greater than a predetermined time. Item 10. An abnormality determination device according to Item 1.   The monitoring means includes means for monitoring the abnormality of the detection means depending on whether or not the time during which the difference value is equal to or greater than a predetermined threshold continues for a predetermined time or more. The abnormality determination device according to claim 1.   The determination means includes means for determining an abnormal detection means based on whether or not the voltage value of the load circuit by the second detection means is substantially 0 after the discharge process. The abnormality determination apparatus in any one of 1-4.   The determination means includes means for determining that the first detection means is abnormal when the voltage value of the load circuit by the second detection means is substantially 0 after the discharge process. The abnormality determination apparatus in any one of 1-4.   The determination means includes means for determining that the second detection means is abnormal if the voltage value of the load circuit by the second detection means is not substantially 0 after the discharge process. The abnormality determination apparatus in any one of -4.   The abnormality determination device according to claim 1, wherein the power storage device is a battery, the load circuit is an inverter, and the power storage element is a smoothing capacitor of the inverter.

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