JP2013180661A - Electronic control unit and abnormality detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic control unit capable of detecting a failure of a diode.SOLUTION: An electronic control unit 100 includes a first power supply means 12, a second power supply means 19, a first diode D1 whose anode side is connected to the first power supply means, a second diode D2 whose anode side is connected to the second power supply means and whose cathode side is short-circuited with the cathode side of the first diode, a switch means 13 that disconnects and connects the second power supply means and the second diode, a first voltage detection means 14 disposed between the first power supply means and the first diode, and a second voltage detection means 15 disposed between the switch means and the second diode. The electronic control unit also includes a failure detection means 54 that detects that the second diode is failed according to the magnitude relation of a first voltage that the first voltage detection means detects and a second voltage that the second voltage detection means detects.

Description

  The present invention relates to an electronic control device that detects a failure of a component.

  The concept of functional safety is known to ensure the safety of in-vehicle devices. In functional safety, it is determined according to the safety level (ASIL) of a component that a failure of a component or the like can be detected and that a major failure due to the failure is prevented. For example, although a lot of microcomputers are mounted on the vehicle, it is preferable that the elements of the microcomputer are the targets of failure monitoring in terms of functional safety if safety is involved.

  By the way, a vehicle often controls an in-vehicle device in response to ON / OFF of the IG-SW (see, for example, Patent Document 1). Patent Document 1 discloses a function (self-shutdown) in which an arithmetic unit detects that the supply of power supply voltage is interrupted by turning off the IG-SW, and interrupts the supply of constant voltage to the internal circuit after a predetermined time. An electronic control device having an OFF function is disclosed.

  Therefore, depending on the microcomputer, if the ON / OFF of the IG-SW cannot be detected, desired control may be difficult. Regarding the detection of the state of the IG-SW, a technique for detecting a disconnection between on-vehicle devices has been considered (see, for example, Patent Document 2). In Patent Document 2, an IG signal line is determined by determining ON / OFF of IG-SW using a voltage value from a sensor and comparing this determination result with its own IG switch information to determine an abnormal state. A technique for detecting disconnection or short-circuit is disclosed.

JP 2004-189055 A JP 2006-256562 A

  However, there is a fault that is difficult to detect the state of the IG-SW by the method disclosed in Patent Document 2.

  FIG. 1 is an example of a diagram illustrating ON / OFF determination of IG-SW. The control unit 17 on the substrate controls a control object 18 such as a motor. The control target 18 is supplied with power from the battery 12, and the control unit 17 is supplied with the power from the battery 12 or + B power supply after being stepped down. The PIG monitor 14 monitors the voltage of the battery 12 (hereinafter referred to as PIG voltage), and the IG monitor 15 monitors the voltage of the + B power source 19 via the IG-SW (hereinafter referred to as IG voltage). The control unit 17 detects the PIG voltage and the IG voltage. Since the + B power source 19 uses the battery 12 as a power source, the IG voltage and the PIG voltage are approximately the same. The diode D1 on the downstream side of the PIG monitor 14 is for preventing a reverse voltage from being applied to the + B power source 19, and the diode D2 on the downstream side of the IG monitor 15 is applied with a reverse voltage to the battery 12. This is to prevent this.

  When the IG-SW 13 is turned on, the control unit 17 is activated to control the relay circuit 11 to be turned on. As a result, power is supplied from the battery 12 to the controlled object 18 via the relay circuit 11. When the IG-SW 13 is turned off, the voltage detected by the IG monitor 15 becomes low (close to zero), so the control unit 17 detects the IG-SW 13 being turned off and executes a predetermined termination process. Since power is supplied to the control unit 17 from the IG-SW 13 or the battery 12, processing can be performed even when the IG-SW 13 is OFF. After completion of the termination process, the control unit 17 turns off the relay circuit 11.

  However, when the diode D2 downstream of the IG-SW 13 is short-circuited, the IG monitor 15 detects the PIG voltage via the relay circuit 11 even when the IG-SW 13 is turned off. Cannot be detected. If the control unit 17 does not detect the IG-SW 13 being turned off, it will not be detected even if the driving vehicle or the like operates the IG-SW 13 next time, so the initial processing performed immediately after the IG-SW 13 is turned on is not executed. There is a problem.

  In the initial processing, processing related to failure detection such as determination of welding of the relay circuit 11 and response confirmation of the control target 18 is performed, and therefore there is a possibility that failure of components related to the electronic control device cannot be detected. For example, when the relay circuit 11 is welded, power is continuously supplied from the battery 12 to the control target 18 and the control unit 17, so that power is consumed even during IG-OFF.

  Also, from the viewpoint of functional safety, it can be said that it is preferable to install a fail-safe mechanism that detects a failure of the diode D2 and does not cause a failure or suppresses the failure.

  In view of the above problems, an object of the present invention is to provide an electronic control device capable of detecting a failure of a diode.

  The present invention includes a first power supply means, a second power supply means, a first diode having an anode connected to the first power supply means, and an anode connected to the second power supply means A second diode in which the cathode side and the cathode side of the first diode are short-circuited, a switch means for connecting and disconnecting the second power supply means and the second diode, and the first power supply means, An electronic control device comprising: first voltage detection means disposed between first diodes; and second voltage detection means disposed between the switch means and a second diode, According to the magnitude relationship between the first voltage detected by the first voltage detection means and the second voltage detected by the second voltage detection means, the failure of the second diode is detected. Fault detection means And wherein the Rukoto.

  An electronic control device capable of detecting a failure of a diode can be provided.

It is an example of the figure explaining determination of ON / OFF of IG-SW. It is an example of the figure explaining the rough method of determination whether the diode D2 is short-circuited. It is an example of the schematic block diagram of an electronic controller. It is an example of the figure explaining the outline of motor control. It is an example of the functional block diagram which performs the OFF determination of IG-SW, and the short determination of the diode D2 in a control part. It is an example of the flowchart figure which shows the procedure in which a control part performs the OFF determination of IG-SW, and the short determination of the diode D2. It is a figure which shows an example of the simulation result explaining the relationship between a PIG voltage and IG voltage. (Example 2) which is an example of the flowchart figure which shows the procedure in which a control part performs OFF determination of IG-SW, and short determination of the diode D2. (Example 3) which is an example of the flowchart figure which shows the procedure in which a control part performs OFF determination of IG-SW, and short determination of the diode D2.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  Consider a case where the diode D2 is short-circuited in the configuration shown in FIG. As described above, in this case, the control unit 17 cannot detect that the IG-SW 13 is turned off from the IG voltage. For this reason, in this embodiment, OFF of the IG-SW 13 is detected on the assumption that the IG voltage does not become zero.

  Specifically, the control unit 17 detects that the IG-SW 13 is OFF by detecting that the alternator is stopped. Further, it is detected that the diode D2 is short-circuited by comparing the IG voltage and the PIG voltage. When the alternator is stopped and the diode D2 is short-circuited, the control unit 17 turns off the relay circuit 11 and stops the electronic control unit.

  FIG. 2 is an example of a diagram illustrating a schematic method for determining whether or not the diode D2 is short-circuited. In FIG. 2, the situation is divided into four situations depending on whether or not the alternator is stopped and whether or not IG voltage <PIG voltage.

When the alternator is stopped When the alternator is stopped, the IG-SW 13 of a general vehicle powered by the internal combustion engine is OFF. Using this, the control unit 17 determines that the IG-SW 13 is OFF when the alternator is stopped.

When IG voltage <PIG voltage When IG voltage <PIG voltage, it can be estimated that the PIG voltage exceeds the diode D2 and affects the IG voltage, so it can be determined that the diode D2 is short-circuited.

Therefore, the following four states can be determined depending on whether the alternator is stopped and whether or not IG voltage <PIG voltage.
(I) IG voltage <PIG voltage and alternator stop (ii) IG voltage <PIG voltage and alternator stop (iii) IG voltage <PIG voltage and alternator not stopped (iv) IG voltage <PIG voltage and alternator The control unit 17 that has not stopped determines that the diode D2 is short-circuited when it is determined that (i) “IG voltage <PIG voltage and alternator stop”. In this case, by performing the termination process, the initial process can be performed when the IG-SW 13 is turned on next time. It should be noted that although the alternator is stopped in (ii), the IG-SW 13 is ON because it is possible to determine whether the diode D2 is short-circuited when the IG-SW is OFF and the diode D2 is not short-circuited when the IG-SW is ON. This is to explain that there is.

[Configuration example]
FIG. 3 shows an example of a schematic configuration diagram of the electronic control device. The electronic control device 100 will be described as functioning as a control device for electric power steering, but can detect a short circuit of the diode D2 and OFF of the IG-SW 13 regardless of the type of the electronic control device.

  The electronic control device 100 is connected to the relay circuit 11, the motor 22, and the IG-SW 13. The relay circuit 11 turns on / off the power supplied from the battery 12 to the electronic control device 100. Once the relay circuit 11 is turned ON, even if the IG-SW 13 is turned OFF, the ON state is maintained unless the relay circuit 11 is turned OFF.

  The IG-SW 13 is interlocked with the ON / OFF of the start button operated by the driver of the vehicle from the driver's seat, or the IG position and the ACC position (or OFF position) where the mechanical key is inserted into the key cylinder to perform the rotation operation. It is an electric switch that opens and closes. When an occupant such as a driver operates the start button, for example, the IG-SW 13 connects the + B power source 19 and the electronic control device 100, and when the start button is turned off, the + B power source 19 and the electronic control device 100 are disconnected.

  Note that the output voltage of the battery 12 (the output voltage of the relay circuit 11) and the voltage of the + B power source 19 are approximately the same. However, even if the two voltages are different, it can be dealt with by adjusting thresholds 1 and 2 described later.

  The electronic control device 100 is controlled by the control unit 17. First, power that is stepped down by the DC / DC converter 16 is supplied to the control unit 17 from both the relay circuit 11 and the IG-SW 13. Since power is supplied from the two systems of the relay circuit 11 and the IG-SW 13, the control unit 17 can operate even if one of them is disconnected.

  On the power supply line from the relay circuit 11 to the DC / DC converter 16, a PIG monitor 14 and a diode D1 are arranged in order from the relay side. On the power supply line from the IG-SW 13 to the DC / DC converter 16, an IG monitor 15 and a diode D2 are arranged in order from the IG-SW side. The PIG monitor 14 is a sensor that detects a voltage between the relay circuit 11 and the diode D1, and the IG monitor 15 is a sensor that detects a voltage between the IG-SW 13 and the diode D1. The PIG monitor and the IG monitor are voltage detection circuits. For example, the PIG monitor and the IG monitor can be mounted by A / D converting a voltage divided by two resistors, or by arranging a voltage detection IC or the like.

  The diode D1 prevents the + B power source 19 on the IG-SW side from being reversely connected to the relay side battery, and the diode D2 prevents the relay side battery from being reversely connected to the + B power source 19 on the IG-SW side.

  Further, the electronic control device 100 shown in the figure has a CAN controller 31. The CAN controller 31 is connected to another controller via the CAN bus 32, receives a CAN frame transmitted on the CAN bus 32 during the IG-ON, and receives a CAN bus according to an instruction from the control unit 17. A CAN frame is transmitted to 32. The CAN frame to be received and the electronic control device 100 of the transmission destination are determined in advance. In addition, the electronic control device 100 includes an A / D converter, an I / O channel, and the like, but is omitted. Further, the CAN controller 31 can be configured to be included in the control unit 17.

  A torque sensor 24 is disposed on the steering shaft 25. A multipolar magnet is disposed on the input shaft side (steering wheel side) of the steering shaft 25, and a yoke is disposed on the output shaft side (steering gear side). The input shaft and the output shaft are connected via a torsion bar. A Hall element is arranged outside the yoke, and when the torsion bar is twisted, the relative value of the yoke and the multi-pole magnet changes, so that the Hall element detects a change in magnetic flux, and thus torque is detected.

  Further, a rotation angle sensor 23 that detects the rotation angle of the motor 22 is disposed. Each rotation sensor 23 is, for example, a resolver, but the rotation angle of the motor 22 may be detected by any method. In the case of a resolver, a primary coil is disposed on the rotor and two secondary coils are disposed on the stator, and the secondary coils of the stator are at an angle of 90 degrees with each other. When an AC voltage is applied to the primary side, a voltage is generated in the secondary coil by electromagnetic induction. Since the voltage generated in the secondary coil at that time is a function of the rotor angle φ (sin φ and cos φ), the resolver converts this into a motor electrical angle θ and outputs it to the controller 17.

  The inverter 21 includes a plurality of switching elements 29 such as FETs, for example, and uses the battery 12 as a power source to turn the switching elements 29 on and off by a PWM signal from the control unit 17. Thereby, the U-phase current IU, the V-phase current IV, and the W-phase current IW are generated, and the motor 22 is driven. Note that the output from the battery 12 may be boosted by a booster circuit. The booster circuit includes a capacitor, a reactor, and a switching element that controls accumulation and release of energy in the reactor.

  Two of the three-phase currents flowing through the motor 22 are detected by the current sensors 27 and 28 and output to the control unit 17. Since the motor currents IU, IV, and IW have a certain relationship, the control unit 17 can calculate the remaining one-phase current by adding the two phase currents and inverting the sign.

  The control unit 17 is called a general microcomputer, computer, or information processing device, and includes a CPU, a RAM, a ROM, and the like. In addition, circuits such as a timer, an interrupt controller, a DMAC, a bridge, and a bus are omitted, but the configuration is the same as that of a known microcomputer. The CPU executes a program stored in the ROM using the RAM as a working memory. When the CPU executes the program, motor control and abnormality monitoring are possible.

  The electronic control apparatus 100 according to the present embodiment detects steering torque, calculates assist torque that assists the driver's steering, and drives the motor 22. More specifically, the assist direction is determined based on the torque detected by the torque sensor 24, and the assist torque generated by the motor 22 is calculated based on the torque and the vehicle speed detected by a vehicle speed sensor (not shown). The vehicle speed signal is acquired by the CAN controller 31 from another electronic control device (for example, a meter ECU). The reason why the vehicle speed is used is that a large assist torque is required when the vehicle speed is low, and a large steering feeling is provided by reducing the assist torque when the vehicle speed is high. The motor control will be described below.

  The motor 22 is, for example, a DC motor, a DC brushless motor, or the like, but the type thereof is not limited as long as the steering shaft 25 can be driven.

[Motor control]
FIG. 4 is an example of a diagram illustrating an outline of motor control. Each function of FIG. 4 is provided by the control unit 17. The assist torque calculation unit 41 calculates assist torque from the torque signal and the vehicle speed signal detected by the torque sensor. The assist torque calculation unit 41 has a map in which the assist torque is associated with the torque and the vehicle speed in advance, and calculates the assist torque with reference to this map.

  The electronic control device 100 of this embodiment performs vector control of the motor torque. For this reason, it is necessary to calculate the current in each of the two axes of the d axis that is the magnetic pole axis of the rotor of the motor 22 and the q axis that is electrically rotated 90 degrees with respect to the d axis. The q-axis current is proportional to the torque generated by the motor 22, and the d-axis current is proportional to the excitation current. Therefore, the assist torque calculated by the assist torque calculation unit 41 is supplied to the q-axis torque control unit 42.

  The d-axis magnetic pole current control unit 43 generally controls the d-axis current so that the d-axis current = 0, but if necessary, by making the d-axis current and the q-axis current substantially equal, Field weakening control can be performed.

  The q-axis torque control unit 42 determines the control amount Cq of the q-axis current by PI control, for example. For feedback control, the q-axis torque control unit 42 receives q-axis current from the three-phase two-axis conversion unit 46. Similarly, the d-axis magnetic pole current control unit 43 determines the control amount Cd of the d-axis current by PI control, for example. For feedback control, d-axis current is input to the d-axis magnetic pole current control unit 43 from the three-phase two-axis conversion unit 46.

The three-phase two-axis converter 46 calculates a q-axis current and a d-axis current from the three-phase currents IU, IV, IW of the motor 22 and the motor electrical angle θ. The q-axis current and the d-axis current are calculated by the following formulas, for example. The conversion formula is an example, and other known conversion formulas can be employed.
q-axis current = √ (2/3) {− sinθ · IU−sin (θ−120) · IV−sin (θ + 120) · IW}
d-axis current = √ (2/3) {cosθ · IU + cos (θ−120) · IV + cos (θ + 120) · IW}
The q-axis torque control unit 42 calculates a q-axis current calculated from the three-phase currents IU, IV, IW and the motor rotation angle θ and a q-axis current deviation Δq determined from the assist torque, and performs PI control to obtain the deviation Δq. Performs an operation that becomes zero. The obtained control amount Cq of the q-axis current is output to the 2-axis 3-phase conversion unit 44. The d-axis magnetic pole current control unit 43 calculates a deviation Δd between the d-axis current calculated from the three-phase currents IU, IV, IW and the motor rotation angle θ and the zero d-axis current, and the deviation Δd is zero by PI control. Perform an operation that becomes. The obtained control amount Cd of the d-axis current is output to the two-axis three-phase conversion unit 44.

The two-axis three-phase conversion unit 44 converts the two-axis signals of the q-axis current control amount Cq and the d-axis current control amount Cd into three-phase signals SU, SV, and SW. The three-phase signals SU, SV, SW are calculated from the control amounts Cq, Cd and the motor electrical angle θ, for example, by the following formula.
SU = √ (2/3) {sin (θ + π / 2) · Cd + sinθ · Cq}
SW = √ (2/3) {− sin (θ + π / 6) · Cd−sin (θ + 2π / 3) · Cq}
SV = -SU-SW
The PWM converter 45 generates a duty signal (PWM signal) having a pulse width proportional to the magnitude of each of the three-phase currents IU, IV, and IW and outputs the duty signal to the inverter 21.

[OFF determination of IG-SW with diode D2 shorted]
FIG. 5 is an example of a functional block diagram in which the controller 17 performs the IG-SW 13 OFF determination and the diode D2 short determination. The control unit 17 includes a non-steering determination unit 51, an alternator stop determination unit 53, a short determination unit 54, and an IG-OFF control unit 52. The non-steering determination unit 51 determines whether or not the steering wheel 26 of the vehicle is being steered. When it is determined that the steering wheel 26 is not steered, a non-steering detection notification is output to the alternator stop determination unit 53 and the short determination unit 54.

  When the alternator stop determination unit 53 acquires the non-steering detection notification, the alternator stop determination unit 53 determines whether or not the alternator is stopped. An alternator is a generator that rotates with an engine to generate electricity. When the engine rotates when the IG-SW 13 is turned on, the alternator rotates at the same rotation speed or a rotation speed corresponding to the gear ratio of a reduction mechanism (not shown). Therefore, it can be estimated that the IG-SW 13 is OFF because the alternator is stopped. Although it can be detected from the engine speed or the like that the engine is stopped, the electronic control unit 100 cannot acquire the engine speed by CAN communication or the like when the IG-SW 13 is OFF.

  When the non-steering detection notification is acquired, the short determination unit 54 determines whether or not the diode D2 is short-circuited. Since the alternator stop determination and the short determination can be performed independently, the short determination can be performed during the alternator stop determination. Details will be described later.

  The IG-OFF control unit 52 performs IG-OFF control when the alternator stop determination unit 53 determines that the alternator is stopped and the short determination unit 54 determines that the diode D2 is short-circuited. The IG-OFF control includes a termination process. As the end processing, for example, the control parameters of the motor 22, the operation time, the motor temperature, etc. are read from the RAM and saved in the flash memory, or if there is a movable part, it is saved in the storage state. Then, when the end process is completed, the relay circuit 11 is controlled to be OFF. Since the IG-SW 13 is already OFF, the power is not supplied to the control unit 17 and the control unit 17 stops. Therefore, power consumption can be suppressed, and at the next start-up, the control unit 17 can perform an initial process and reliably determine whether or not the relay circuit 11 is welded.

  FIG. 6 is an example of a flowchart illustrating a procedure in which the control unit 17 performs the IG-SW 13 OFF determination and the diode D2 short determination. The procedure of FIG. 6 is executed at predetermined cycle times, for example.

  The non-steering determination unit 51 determines whether or not the steering torque detected by the torque sensor 24 is zero (S10). The fact that the steering torque is zero means that the driver is not applying a force in the steering direction to the steering wheel 26.

  When the steering torque is zero (Yes in S10), the non-steer determination unit 51 determines whether or not the motor electrical angle θ has not changed (S20). Since the motor electrical angle θ is detected from the resolver every cycle time, the motor electrical angle θ in the previous cycle is recorded and compared with the current motor electrical angle θ. The fact that there is no change in the motor electrical angle θ means that the motor 22 is not rotating, so it can be seen that the steering wheel 26 is not rotating.

  Even if the steering torque is zero and there is no change in the motor electrical angle θ, the IG-SW is not OFF and the driver may be driving. For example, when the vehicle is traveling on a straight road at high speed, or when the vehicle is stopped by a signal or the like.

  For this reason, the non-steering determination unit 51 further determines whether or not the CAN communication is abnormal (S30). If the IG-SW 13 is OFF, the CAN controller 31 described above does not receive a CAN frame from another electronic control device. Even if the electronic control device 100 tries to transmit a CAN frame, if the IG-SW 13 is OFF, the differential voltage is dominant (0), so the CAN bus 32 is always in use and cannot transmit the CAN frame. Therefore, the non-steering determination unit 51 detects an abnormality in CAN communication when the IG-SW 13 is OFF. A state in which an abnormality in CAN communication is detected is referred to as a diode failure detection start state.

  In addition, it is not necessarily a non-steering state only by having abnormality in CAN communication. This is because the CAN controller 31 temporarily buses off or an abnormality has occurred in the CAN controller 31. Therefore, in addition to determining all of steps S10 and S20, it is preferable to determine that the diode failure detection start state is abnormal in CAN communication.

  It may be extremely rare that the unsteered state and the diode failure detection start state occur simultaneously for a long period of time. Therefore, when these are detected over a predetermined time, it is determined that the IG-SW is OFF.

  Before determining that the IG-SW is OFF, it is determined that the non-steering state and the diode failure detection start state are not in the non-steering state and the diode failure detection start state. This is because it is not necessary to determine that the Further, in order to control the steering torque in the determination of whether or not the IG-SW described below is OFF, it is desirable to be in a non-steering state and a diode failure detection start state.

  When determining whether the alternator is stopped or the diode D2 is short-circuited for another electronic control device, it is only necessary to monitor the sensing result of the object controlled by the electronic control device, the absolute value of the control amount, or the temporal change. For example, the brake ECU monitors whether the master cylinder pressure is zero, the state of the stop lamp switch, the time variation of the electromagnetic valve opening of the brake actuator, and the like.

<Alternator stop judgment>
If it is determined that the state is the non-steering state and the diode failure detection start state, the alternator stop determination unit 53 determines the alternator stop (S50).

  As described above, it is difficult for the electronic control device 100 to directly monitor the rotation speed, the charge amount, and the like of the alternator in a state where there is an abnormality in CAN communication. Therefore, the alternator stop determination unit 53 focuses on the PIG voltage.

  The alternator stop determination unit 53 first requests the q-axis torque control unit 42 as it is, and requests the d-axis magnetic pole current control unit 43 to set the d-axis current target value to a value other than zero. (S501). The target value of the q-axis current may be set to zero, for example. Setting the target value of the q-axis current to zero is equivalent to setting the assist torque to zero, so that it is possible to prevent the motor 22 from rotating and moving the steering wheel 26. Since it is already determined that the state is the non-steering state and the diode failure detection start state, the steering of the driver is not limited even if the steering wheel 26 is controlled to be stationary. Even if it is limited, the driver can override the steering wheel 26 to overcome the assist torque. The control in step S501 is hereinafter referred to as “static power consumption control”.

  Further, setting the target value of the d-axis current to a value other than zero means increasing the excitation current, and thus means that the motor 22 consumes electric power (this electric power is not converted into torque, so it is almost It turns into heat.) As shown in FIG. 3, even if the IG-SW 13 is turned on, the power is not supplied from the + B power source 19 to the motor 22 by the diode D1. For this reason, the electric power consumed by the motor 22 is always supplied from the battery 12 via a relay.

By the way, when current flows from the battery 12, the battery voltage generally decreases. However, if the alternator is not stopped, the alternator generates power so as to maintain the battery voltage, so the battery voltage does not drop significantly. In this embodiment, the battery voltage fluctuation is detected by the PIG voltage and compared with the threshold value 1 to determine whether or not the alternator is stopped (S502).
-PIG voltage <threshold value 1-> alternator is stopped-PIG voltage> threshold value 1-> alternator is not stopped As described above, the alternator stop determination unit 53 determines that the alternator is stopped when the PIG voltage is less than threshold value 1. (S503). As described above, since the alternator is stopped, it can be estimated that the IG-SW 13 is OFF.

The threshold 1 can be determined experimentally. For example, if the rated battery voltage is V ₀ [V], the threshold 1 is set to a value lower by about 1 to 2 [V] than V ₀ .

<Short judgment>
Next, the short determination unit 54 performs short determination of the diode D2 (S60). The short determination can be executed regardless of the result of the alternator stop determination. Further, when the short determination is performed, the control of the static power consumption control may or may not be performed (S601). This is because the accuracy of the short determination is not greatly affected by the presence or absence of static power consumption control. However, by performing the short determination under the static power consumption control in S601, the alternator stop determination and the short determination can be performed in parallel.

  The short determination unit 54 determines whether or not “IG voltage−PIG voltage <threshold 2” (S602). The IG voltage is lower when the diode D2 is short-circuited than when the diode D2 is not short-circuited. The PIG voltage increases slightly when the diode D2 is short-circuited. As a result, when the diode D2 is short-circuited, IG voltage <PIG voltage. Therefore, for example, by setting the threshold value 2 to zero, it is detected that IG voltage <PIG voltage.

  When “IG voltage−PIG voltage <threshold 2” (Yes in S602), the short determination unit 54 determines that the diode D2 is short-circuited (S603).

  As will be described below, since the difference between the IG voltage and the PIG voltage when the diode D2 is short-circuited is not large, it is conceivable that IG voltage> PIG voltage due to a diode, transistor, wiring, parasitic capacitance, etc. (not shown). . Therefore, the magnitude relationship between the IG voltage and the PIG voltage is not absolute, and the feature of this embodiment is to determine whether the diode D2 is short-circuited by focusing on the magnitude of the IG voltage and the PIG voltage. For this reason, the threshold value 2 can be determined experimentally as appropriate.

  The IG-OFF control unit 52 determines whether or not the IG-SW 13 is OFF (alternator stopped) and the diode D2 is short-circuited (S70). If the IG-SW 13 is not OFF or the diode D2 is not short-circuited (S70 No), the determination from step S10 is repeated. When the IG-SW 13 is OFF (alternator stopped) and the diode D2 is short-circuited, the IG-OFF control unit 52 performs IG-OFF control (end processing) (S80).

[Short determination of diode D2 and OFF determination of IG-SW]
FIG. 7 is a diagram illustrating an example of a simulation result for explaining the relationship between the PIG voltage and the IG voltage. In this embodiment, since it is unknown whether the IG-SW 13 is OFF or not, a short circuit of the diode D2 is detected. Therefore, even if the alternator stops (the amount of power generation is zero), the + B power source 19 on the IG-SW side It is not zero (IG-SW is ON in (ii)).

  FIG. 7 (i) shows the relationship between the PIG voltage and the IG voltage when the alternator is stopped (IG-SW OFF) and the diode D2 is shorted, and FIG. 7 (ii) is the diode D2 when the alternator is stopped (IG-SW ON). FIG. 7 (iii) shows the relationship between the PIG voltage and the IG voltage when the alternator is not stopped (IG-SW OFF) and the diode D2 is short-circuited. 7 (iv) shows the relationship between the PIG voltage and the IG voltage when the alternator is not stopped (IG-SW ON) and the diode D2 is not short-circuited. The alternator stop determination unit 53 starts static power consumption control at times t1 to t4 shown in the figure.

  In FIG. 7 (i), the PIG voltage is greatly reduced from V1 [V], and in FIG. 7 (ii), the PIG voltage is greatly reduced from V2 [V]. Therefore, it can be determined that the alternator is stopped. On the other hand, in FIG. 7 (iii), the PIG voltage decreases from V3 [V] to about V4 [V], and in FIG. 7 (iv), the PIG voltage decreases from V5 [V] to about V6 [V]. However, it can be seen that the amount of decrease is small. Therefore, it can be determined that the alternator is not stopped. In FIG. 7 (ii), the IG voltage is not zero (IG-SW ON) in order to explain that the short circuit of the diode D2 can be detected on the assumption that it is unknown whether the IG-SW 13 is OFF. .

  In FIGS. 7 (i) and (iii), IG voltage <PIG voltage regardless of static power consumption control. Therefore, it can be determined that the diode D2 is short-circuited. 7 (ii) and (iv), the IG voltage and the PIG voltage are the same or IG voltage> PIG voltage regardless of the static power consumption control. Therefore, it can be determined that the diode D2 is not short-circuited.

In this way, depending on the combination of whether or not the alternator is stopped
(I) The diode D2 is short-circuited and the alternator stop can be distinguished from the other three states.

  Since the state (i) can be detected separately from the other states, the electronic control device 100 can estimate the OFF of the IG-SW 13 and stop the electronic control device 100 even if the diode D2 is short-circuited. Can be initialized at startup.

  As described with reference to FIG. 7, the change in the IG voltage is not so large between the state in which the diode D2 is short-circuited and the state in which it is not short-circuited. Therefore, depending on the accuracy of the IG monitor 15 and the PIG monitor 14, there is a possibility that PIG voltage> IG voltage in FIG. In this case, the states of FIGS. 7 (i) and (ii) cannot be distinguished (the states of FIGS. 7 (iii) and (iv) cannot be distinguished). Therefore, in this embodiment, an electronic control device 100 that detects a short circuit of the diode D2 without comparing the PIG voltage and the IG voltage will be described.

  The hardware configuration and the functional block diagram of the present embodiment are the same as those of the first embodiment, but the method for determining the short of the diode D2 by the short determination unit 54 is different. The short determination unit 54 of the present embodiment detects a short circuit of the diode D2 by turning off the relay circuit 11 without using the PIG voltage and the IG voltage.

  FIG. 8 is an example of a flowchart illustrating a procedure in which the control unit performs the IG-SW OFF determination and the diode D2 short determination. In the procedure of FIG. 8, the processing from step S10 to step S50 is the same as that of FIG. Also, the alternator stop determination procedure was omitted.

  When the alternator stop determination is completed in step S50, the short determination unit 54 determines whether or not the IG-SW 13 is OFF (S62).

  If the IG-SW 13 is not OFF (No in S62), it is difficult to determine a short in the present embodiment, so the processing from step S10 is repeated.

  When the IG-SW 13 is OFF (Yes in S62), the short determination unit 54 starts short determination (S64).

  First, the short determination unit 54 determines whether or not a certain time has elapsed since it was determined that the alternator has stopped (S611). This fixed time is a time sufficiently longer than the time until the end processing is completed and the control unit 17 turns off the relay circuit 11. Conventionally, when the IG voltage becomes substantially zero, the electronic control unit 100 estimates that the IG-SW 13 is OFF (determines that the alternator is stopped) and starts the termination process. When the diode D2 is short-circuited, the IG voltage does not become zero even when the IG-SW 13 is turned off, so the termination process is not performed. Therefore, when a certain period of time has elapsed since it was determined that the alternator has stopped, it is estimated that the diode D2 may be short-circuited, and short-circuit determination is performed. Note that the determination in S611 is equivalent to the determination that the IG voltage is sufficiently larger than zero.

  For this reason, the short determination unit 54 stores the start of the short determination in the nonvolatile memory (S612). By storing in the non-volatile memory, even if the control unit 17 is reset, the record can be read after the restart. Note that information necessary for the end process is recorded together with the record of the start of the short determination.

  Next, the short determination unit 54 controls the relay circuit 11 to be OFF (S613). If the relay circuit 11 is turned off while the IG-SW 13 is off, no power is supplied to the control unit 17. Therefore, similarly to the case where the diode D2 is not short-circuited and the IG-SW is turned off, the control unit 17 stops.

  Then, when the driver or the like turns on the IG-SW 13 next time, the control unit 17 is restarted (S614). For example, after the initial processing is completed by restarting, the short determination unit 54 determines whether or not a short determination start record is stored in the nonvolatile memory (S615).

  If the start record of the short determination is not stored in the nonvolatile memory (No in S615), the short returns cannot be determined, and the process returns to step S66.

  When the start record of the short determination is stored in the nonvolatile memory (Yes in S615), the short determination unit 54 determines that the diode D2 is shorted (S616). That is, since the diode D2 is short-circuited, the IG voltage does not become zero, and it can be seen that the relay circuit 11 is turned off by the short-circuit determination. After the determination, the start record of the short determination is deleted.

  Returning to step S66, the IG-OFF control unit 52 determines whether or not the diode D2 is short-circuited (S66). When the diode D2 is not short-circuited (No in S66), the determination from Step S10 is repeated. When the diode D2 is short-circuited (Yes in S66), the IG-OFF control unit 52 performs IG-OFF control (end processing) (S80). The IG-OFF control unit 52 also records that the diode D2 is short-circuited in the termination process. Therefore, when it is determined next time that the alternator has stopped, the processing of S611 to S616 becomes unnecessary, and the relay circuit 11 can be turned off early.

  Thus, according to the present embodiment, even if the accuracy of the PIG monitor 14 and the IG monitor 15 is low, a short circuit of the diode D2 can be determined.

  In the first embodiment, the alternator stop determination and the diode D2 short determination are performed independently. However, if the fact that the alternator is stopped is used, the short determination of the diode D2 can be easily performed. In the present embodiment, an electronic control device 100 that performs short-circuit determination of the diode D2 using the fact that the alternator is stopped will be described.

  The hardware configuration and the functional block diagram of the present embodiment are the same as those of the first embodiment, but the method for determining the short of the diode D2 by the short determination unit 54 is different.

  FIG. 9 is an example of a flowchart illustrating a procedure in which the control unit 17 performs the IG-SW OFF determination and the diode D2 short determination. The procedure in FIG. 9 is almost the same as that in FIG. 8, and the short determination in step S64 is different.

  If it is determined in step S62 that the alternator is stopped, the short determination unit 54 determines whether or not the IG voltage is substantially zero (S621).

  Since the IG-SW 13 is OFF when the alternator is stopped, no power should be supplied from the + B power source 19 to the IG monitor 15. Therefore, when the IG voltage is not substantially zero (No in S621), it can be predicted that the diode D2 is short-circuited, and the short determination unit 54 determines that the diode D2 is short-circuited (S622). Since the subsequent processing is the same as that of the second embodiment, description thereof is omitted.

  According to the present embodiment, it is possible to determine whether or not the diode D2 is short-circuited using the fact that the alternator is stopped.

D1 D2 Diode 11 Relay circuit 13 IG-SW
DESCRIPTION OF SYMBOLS 14 PIG monitor 15 IG monitor 17 Control part 22 Motor 24 Torque sensor 51 Non-steering determination part 52 IG-OFF control part 53 Alternator stop determination part 54 Short determination part 100 Electronic controller

Claims (7)

A first power supply means; a second power supply means;
A first diode having an anode connected to the first power supply means;
A second diode in which the anode side is connected to the second power supply means, and the cathode side and the cathode side of the first diode are short-circuited;
Switch means for connecting / disconnecting between the second power supply means and the second diode;
First voltage detection means disposed between the first power supply means and the first diode;
An electronic control unit comprising: a second voltage detection unit disposed between the switch unit and a second diode;
Detecting failure of the second diode according to the magnitude relationship between the first voltage detected by the first voltage detecting means and the second voltage detected by the second voltage detecting means. Fault detection means to
An electronic control device. In a state where the power of the first power supply means is consumed by an electric load that operates the first power supply means as a power source,
If the first voltage is below a threshold,
A power generation device stop detection means for detecting that the power generation device whose stop state or operation state is linked to the connection / disconnection of the switch means is stopped, and that the switch means is in a disconnected state,
The electronic control device according to claim 1, comprising: The electrical load is a vector controlled electric motor;
The power generation device stopping means causes the electric motor to consume the power of the first power supply means by setting the target current of the d-axis current proportional to the excitation current to other than zero.
The electronic control device according to claim 2. The said failure detection means detects that the said 2nd diode has failed when said 2nd voltage is smaller than said 1st voltage. The any one of Claims 1-3 characterized by the above-mentioned. The electronic control device described. Based on the detection results of the driver's steering state detecting means and the other device operating state detecting means for detecting the operating state of the other device operating in conjunction with ON / OFF of the IG, the non-steering state and communication with the other device A determination means for determining whether or not an abnormality has occurred;
The failure detection means determines that the magnitude relationship between the first voltage and the second voltage is determined when the determination means determines that the steering is in a non-steering state and a communication abnormality with the other device is occurring. In response, detecting that the second diode is faulty,
The electronic control device according to claim 4. A first power supply means; a second power supply means;
A first diode having an anode connected to the first power supply means;
A second diode in which the anode side is connected to the second power supply means, and the cathode side and the cathode side of the first diode are short-circuited;
Switch means for connecting / disconnecting between the second power supply means and the second diode;
First voltage detection means disposed between the first power supply means and the first diode;
Second voltage detection means disposed between the switch means and a second diode;
A relay circuit for connecting and disconnecting the first power supply means and the first diode;
An electronic control device comprising:
When the first voltage is less than a threshold value in a state where the electric power of the first power supply means is consumed by an electric load that operates the first power supply means as a power supply, the switch means is disconnected / connected. A power generation device stop detection means for detecting that the power generation device linked with the stop state or the operation state is stopped and the switch means is in a disconnected state,
When a predetermined time has elapsed since the power generation device stop means detected that the power generation device is stopped, or when the second voltage is not substantially zero, failure determination information is recorded in the nonvolatile memory. Failure determination means for turning off the relay circuit,
An electronic control device. A first power supply means; a second power supply means;
A first diode having an anode connected to the first power supply means;
A second diode in which the anode side is connected to the second power supply means, and the cathode side and the cathode side of the first diode are short-circuited;
Switch means for connecting / disconnecting between the second power supply means and the second diode;
First voltage detection means disposed between the first power supply means and the first diode;
An abnormality detection method for an electronic control device comprising: a second voltage detection means disposed between the switch means and a second diode,
The first voltage detection means detecting a first voltage;
The second voltage detection means detecting a second voltage;
A step of detecting a failure of the second diode according to a magnitude relationship between the first voltage and the second voltage;
An abnormality detection method comprising:

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