JP2015211591A - Failure diagnosis device for driving device for brushless motor, and failure diagnosis method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately perform failure diagnosis in simple configuration regarding a failure diagnosis device for a driving device for a brushless motor and a failure diagnosis method.SOLUTION: The failure diagnosis device for the driving device for the brushless motor includes: a plurality of drive terminals connectable to motor terminals of a plurality of phases included in the brushless motor; and a pair of switching elements provided correspondingly for each phase and connected in series between a power supply (+) line and a power supply (-) line of a DC power source. In the state where the motor terminals of the brushless motor are not connected to the plurality of drive terminals, between a pair of switching element of one phase, a switching element at a side of the power supply (+) line is turned on and between a pair of switching element of another phase, qa switching element at a side of the power supply (-) line is turned on. On the basis of whether a current flows from the side of the power supply (+) line to the side of the power supply (-) line in the driving device, it is diagnosed whether there is any failure in the driving device.

Description

  The present invention relates to a failure diagnosis device and a failure diagnosis method for a brushless motor drive device, and more particularly to a plurality of drive terminals connectable to a plurality of motor terminals of a brushless motor, and corresponding to each phase of a brushless motor. The present invention relates to a device and a method for diagnosing a failure of a brushless motor drive device having a pair of switching elements connected in series between a power source + line and a power source-line of a DC power source.

  2. Description of the Related Art Conventionally, an apparatus and a method for diagnosing a failure that has occurred in a brushless motor or its energization path are known (see, for example, Patent Document 1). The failure diagnosis apparatus described in Patent Document 1 includes a plurality of drive terminals that can be connected to a plurality of motor terminals of a brushless motor, and a DC power supply + line and a power supply provided corresponding to each phase of the brushless motor. A pair of switching elements connected in series with the line, and after all of the switching elements in the brushless motor drive device are turned off, the power supply + line side of the pair of switching elements of one phase A voltage is applied to one of the motor terminals by turning on the switching element. Based on the terminal voltage generated at each motor terminal, a failure diagnosis of circuit breakage, + B short circuit, and GND short circuit on the brushless motor side is performed.

Japanese Patent Application No. 2008-199852

  By the way, in order to accurately perform a failure diagnosis on a brushless motor, it is necessary that the rotation of the brushless motor is completely stopped so that the brushless motor driving device is not affected by the induced voltage caused by the motor rotation. is there. However, in the failure diagnosis device described in Patent Document 1 described above, failure diagnosis is performed on the assumption that the brushless motor and the brushless motor drive device are connected to each other, and therefore the rotation of the brushless motor is stopped. It is necessary to provide a sensor for detecting this, and the cost increases.

  The present invention has been made in view of the above-described points, and an object of the present invention is to provide a failure diagnosis device and a failure diagnosis method for a brushless motor drive device that can accurately perform failure diagnosis with a simple configuration. To do.

  One aspect of the present invention includes a plurality of drive terminals connectable to a plurality of phase motor terminals of a brushless motor, and a DC power supply + line and a power supply-line provided corresponding to each phase of the brushless motor. A device for diagnosing a failure of a brushless motor drive device having a pair of switching elements connected in series between the plurality of drive terminals, wherein the motor terminals of the brushless motor are not connected to the plurality of drive terminals. A switch control means for turning on the switching element on the power source + line side of the pair of switching elements of the phase and turning on the switching element on the power source line side of the pair of switching elements of the other phases; When the switch control by the switch control means is performed, the brushless motor driving device is connected to the power source + line side. A first diagnosis means for diagnosing whether or not the brushless motor driving device is out of order based on whether or not current flows from the power source to the line side. This is a failure diagnosis device.

  One embodiment of the present invention includes a plurality of drive terminals connectable to a plurality of phase motor terminals of a brushless motor, a DC power supply + line and a power supply − provided for each phase of the brushless motor. A method of diagnosing a failure of a brushless motor drive device having a pair of switching elements connected in series with a line, wherein the motor terminals of the brushless motor are not connected to the plurality of drive terminals. When turning on the switching element on the power source + line side among the pair of switching elements in one phase, and turning on the switching element on the power source line side in the pair of switching elements in the other phase, Based on whether or not current flows from the power source + line side to the power source-line side of the brushless motor drive device, Rashiresumota drive device is a fault diagnosis method for a brushless motor driving device comprising a first step of diagnosing whether a failure.

  According to the present invention, failure diagnosis can be performed accurately with a simple configuration.

1 is a configuration diagram of a failure diagnosis device for a brushless motor drive device according to an embodiment of the present invention. FIG. 1 is a schematic external view of a brushless motor driving apparatus according to an embodiment. It is a flowchart of an example of a main routine executed in the failure diagnosis device for the brushless motor drive device of the present embodiment. It is a flowchart of an example of the subroutine performed in the failure diagnosis apparatus of the drive apparatus for brushless motors of a present Example. It is a flowchart of an example of the subroutine performed in the failure diagnosis apparatus of the drive apparatus for brushless motors of a present Example. It is a flowchart of an example of the subroutine performed in the failure diagnosis apparatus of the drive apparatus for brushless motors of a present Example. It is a flowchart of an example of the subroutine performed in the failure diagnosis apparatus of the drive apparatus for brushless motors of a present Example. It is a figure showing an example of the relationship between the input from the electronic control unit in the control part which the drive device for brushless motors of a present Example has, and the output to a switching element.

  Hereinafter, specific embodiments of a failure diagnosis device and a failure diagnosis method for a brushless motor drive device according to the present invention will be described with reference to the drawings.

  FIG. 1 shows a configuration diagram of a failure diagnosis device 12 of a brushless motor drive device 10 according to an embodiment of the present invention. FIG. 2 is a schematic external view of the brushless motor driving apparatus 10 of this embodiment.

  A brushless motor driving device (hereinafter simply referred to as a driving device) 10 according to the present embodiment is a device that rotationally drives the brushless motor 14. The brushless motor 14 is a three-phase brushless motor including a rotor having no energization switching mechanism such as a brush and a commutator, and a stator having three-phase U, V, and W stator coils. The brushless motor 14 is an in-vehicle motor used in a vehicle, for example, a fuel pump that supplies fuel to the engine.

  The drive device 10 has drive terminals 18U, 18V, and 18W that can be connected to motor terminals 16U, 16V, and 16W of each phase of the brushless motor 14. The drive device 10 has a connector 20 provided with drive terminals 18U, 18V, and 18W. Hereinafter, this connector 20 is referred to as a motor-side connector 20. The motor-side connector 20 is also provided with a ground terminal 22. The drive terminals 18U, 18V, 18W of the drive device 10 are connected to the motor terminals 16U, 16V, 16W of the brushless motor 14 via a harness 24 connected to the motor side connector 20. The harness 24 can be attached to and detached from the motor-side connector 20.

  The drive device 10 also has a + B terminal 26 to which a + B potential of a battery that is a DC power source mounted on the vehicle is input, and a GND terminal 28 to which the GND potential of the battery is input. The same potential E as the GND potential input to the GND terminal 28 is input to the ground terminal 22 of the motor-side connector 20 described above. The drive device 10 has a connector 30 provided with a + B terminal 26 and a GND terminal 28. Hereinafter, this connector 30 is referred to as a power supply side connector 30.

  The driving device 10 also has switching elements Su, Sv, Sw provided corresponding to each phase of the brushless motor 14. The switching elements Su, Sv, Sw of each phase are composed of upper and lower switching elements Su, Sd connected in series between a + B line 32 connected to the + B terminal 26 and a GND line 34 connected to the GND terminal 28. Become. Each switching element Suu, Sud, Svu, Svd, Swu, Swd is, for example, an n-channel MOS transistor.

  A common connection point of the U-phase switching elements Suu and Sud is connected to the drive terminal 18U. A common connection point of the V-phase switching elements Svu and Svd is connected to the drive terminal 18V. The common connection point of the W-phase switching elements Swu and Swd is connected to the drive terminal 18W.

  The driving device 10 also has a control circuit 36 mainly composed of a microcomputer. The control circuit 36 is a circuit that controls ON / OFF of each switching element Suu, Sud, Svu, Svd, Swu, Swd. Specifically, pulse width modulation (PWM) control of each switching element Suu, Sud, Svu, Svd, Swu, Swd is performed so that the output adjustment of the brushless motor 14 is performed. Each switching element Suu, Sud, Svu, Svd, Swu, Swd is turned on / off in accordance with an instruction from the control circuit 36.

  The driving device 10 also has a current detection circuit 38 connected to the control circuit 36. The current detection circuit 38 is a circuit for detecting the current Iuvw flowing through the driving device 10 from the + B line 32 side toward the GND line 34 side. The current detection circuit 38 is provided between the switching element Sd on the GND line 34 side and the GND line 34 among the pair of switching elements Su and Sd of each phase. The current detection circuit 38 is composed of, for example, a resistor and outputs a voltage generated between both ends of the resistor. Based on the output of the current detection circuit 38, the control circuit 36 determines whether or not the current Iuvw flows from the + B line 32 side to the GND line 34 side.

  The driving device 10 also has a voltage detection circuit 40 connected to the control circuit 36. The voltage detection circuit 40 uses the potential generated at the common connection point of the switching elements Su and Sd of the respective phases with reference to the GND potential, that is, the output voltages Vu, Vv, and Vw at the drive terminals 18U, 18V, and 18W of the respective phases. It is a circuit for detecting. Based on the output of the voltage detection circuit 40, the control circuit 36 detects the output voltages Vu, Vv, Vw of each phase.

  An electronic control unit (hereinafter referred to as ECU) 42 mainly composed of a microcomputer is connected to the drive device 10. The ECU 42 and the drive device 10 are connected via a communication line 44. One end of the communication line 44 is connected to an SI terminal 45 provided on the power supply side connector 30 of the driving device 10. The ECU 42 is a device that controls the rotation of the brushless motor 14. The ECU 42 mainly gives a rotation instruction to the control circuit 36 of the drive device 10 so that the brushless motor 14 is rotationally driven at a desired rotational speed rpm.

  The ECU 42 has a PWM communication circuit 46 connected to the control circuit 36 of the drive device 10 via the communication line 44. The ECU 42 uses the PWM communication circuit 46 to give the rotation instruction to the control circuit 36 via the communication line 44 by PWM communication. PWM communication is represented by a duty value that is a time ratio of a high time in one pulse. The control circuit 36 controls on / off of the switching elements Su, Sd of each phase according to the duty value by PWM communication from the ECU 42 that is input to the SI terminal 45 via the communication line 44.

  An engine rotation sensor 48 is connected to the ECU 42. The engine rotation sensor 48 is a sensor that outputs a signal corresponding to the engine speed. An output signal from the engine rotation sensor 48 is supplied to the ECU 42. The ECU 42 detects the engine speed based on the output signal of the engine rotation sensor 48 and determines whether or not the engine has stopped rotating.

  The failure diagnosis apparatus 12 has a scan tool 50. The scan tool 50 is detachably connected to the ECU 42 described above. The scan tool 50 includes a failure diagnosis instruction circuit 52 that instructs the ECU 42 to perform a diagnosis of a failure such as a short circuit or an open of the drive device 10. The scan tool 50 is not connected to the ECU 42 when failure diagnosis of the drive device 10 should not be performed, and is connected to the ECU 42 when failure diagnosis of the drive device 10 should be performed. When the execution of failure diagnosis is instructed from the failure diagnosis instruction circuit 52 of the scan tool 50 with the scan tool 50 connected, the ECU 42 performs failure diagnosis of the drive device 10 to the control circuit 36 of the drive device 10. Instruct to do so.

  The failure diagnosis apparatus 12 also has a tester 54 that is a general-purpose measuring instrument. The tester 54 is detachably connected to the driving device 10 described above. The tester 54 measures the output voltages Vu, Vv, and Vw of the drive terminals 18U, 18V, and 18W of the motor-side connector 20 of the drive device 10 with reference to the potential E (that is, the GND potential) of the ground terminal 22. have. The tester 54 is not connected to the drive device 10 when the failure diagnosis of the drive device 10 should not be performed, while the tester 54 is connected to the drive device 10 via the motor side connector 20 when the failure diagnosis of the drive device 10 should be performed. Connected. The tester 54 diagnoses a failure of the drive device 10 based on the output voltages Vu, Vv, and Vw measured by the voltage measurement circuit 56 in a state where the tester 54 is connected to the drive device 10 via the motor-side connector 20.

  Hereinafter, a method for diagnosing a failure of the drive device 10 by the failure diagnosis device 12 of the present embodiment will be described with reference to FIGS.

  FIG. 3 shows a flowchart of an example of a main routine executed in the failure diagnosis device 12 of the drive device 10 of the present embodiment. FIG. 4 shows a flowchart of an example of a subroutine executed in the failure diagnosis device 12 of the drive device 10 of this embodiment. FIG. 5 shows a flowchart of an example of a subroutine executed in the failure diagnosis device 12 of the drive device 10 of the present embodiment. FIG. 6 shows a flowchart of an example of a subroutine executed in the failure diagnosis device 12 of the drive device 10 of this embodiment. FIG. 7 shows a flowchart of an example of a subroutine executed in the failure diagnosis device 12 of the drive device 10 of this embodiment. FIG. 8 is a diagram showing an example of the relationship between the input from the ECU 42 and the output to the switching elements Su and Sd in the control circuit 36 of the drive device 10 of the present embodiment.

  In this embodiment, the failure diagnosis of the drive device 10 is performed without the harness 24 being connected to the motor-side connector 20 of the drive device 10 and without connecting the drive device 10 and the brushless motor 14. The failure diagnosis is performed in a state where the tester 54 is connected to the motor-side connector 20 of the drive device 10.

  After the power is turned on, the ECU 42 determines whether or not a failure diagnosis execution instruction is received from the scan tool 50 (step 100 shown in FIG. 3). If the scan tool 50 is not connected to the ECU 42, or if the scan tool 50 is connected to the ECU 42 but no failure diagnosis execution instruction is sent from the failure diagnosis instruction circuit 52, the ECU 42 Does not receive instructions for performing fault diagnosis. On the other hand, when the scan tool 50 is connected to the ECU 42 and a failure diagnosis execution instruction is sent from the failure diagnosis instruction circuit 52, the ECU 42 receives the failure diagnosis execution instruction from the scan tool 50.

  If the ECU 42 determines in step 100 that the failure diagnosis execution instruction is not received from the scan tool 50, the ECU 42 ends the routine processing shown in FIG. On the other hand, if it is determined that a failure diagnosis execution instruction has been received from the scan tool 50, it is next determined whether or not the engine has stopped based on the output signal of the engine rotation sensor 48 (step 102). ).

  As a result, when the ECU 42 determines that the rotation of the engine has not stopped, the routine processing shown in FIG. On the other hand, when it is determined that the rotation of the engine has stopped, the control circuit 36 or the tester 54 of the drive device 10 performs a process of diagnosing the failure of the drive device 10 (step 104). Specifically, the ECU 42 instructs the control circuit 36 of the drive device 10 to perform the failure diagnosis of the drive device 10 as a process for performing the failure diagnosis of the drive device 10.

  During normal times when the ECU 42 does not instruct the control circuit 36 of the drive device 10 to perform the failure diagnosis, the brushless motor 14 is directed to the control circuit 36 of the drive device 10 via the communication line 44 at a desired rotational speed rpm. A rotation instruction for rotational driving is performed by PWM communication. At this time, the duty value by PWM communication fluctuates in accordance with the desired rotational speed rpm of the brushless motor 14, and specifically, as shown in FIG. It becomes linearly larger within a usage range limited to a part of 100% (specifically, a duty value of 5% to 65%; hereinafter, this usage range is referred to as a normal usage range).

  When the control circuit 36 of the driving device 10 determines that the duty value received by the PWM communication from the ECU 42 is within the normal use range, the brushless motor 14 is driven to rotate at a rotation speed rpm corresponding to the duty value. Further, on / off of each of the switching elements Su and Sd of each phase is controlled. According to such processing, the switching elements Su and Sd of each phase are turned on and off, so that the brushless motor 14 is rotationally driven at a desired rotational speed rpm.

  On the other hand, when the ECU 42 instructs the control circuit 36 of the drive device 10 to execute the failure diagnosis of the drive device 10 in step 104, the ECU 42 issues the failure diagnosis execution instruction by PWM communication. At this time, the duty value by the PWM communication uses a predetermined usage range different from the normal usage range used for instructing the rotation speed rpm of the brushless motor 14 among the duty values 0% to 100%, and further, It fluctuates depending on the phase where failure diagnosis should be performed. For example, as shown in FIG. 8, when instructing the execution of failure diagnosis for the U phase, the duty value 85% is used, and when instructing the execution of failure diagnosis for the V phase, the duty value 90% is used, When instructing the execution of failure diagnosis for the W phase, a duty value of 95% is used.

  When the control circuit 36 of the driving device 10 determines that the duty value received by PWM communication from the ECU 42 is within the predetermined use range that is different from the normal use range, the fault diagnosis for the phase according to the duty value is performed. Perform the process to be performed.

  Specifically, first, the control circuit 36 performs processing for determining an abnormality of the signal SI input to the SI terminal 45 via the communication line 44 (step 110 shown in FIG. 4). As such SI abnormality determination processing, the control circuit 36 first calculates the frequency (PWM frequency) of PWM communication input to the SI terminal 45 via the communication line 44 (step 130 shown in FIG. 5). The calculation of the PWM frequency is performed, for example, so as to be defined by the rising time interval of the high signal of the signal SI.

  Then, the control circuit 36 determines whether or not the PWM frequency calculated in step 130 is within a predetermined specified range (step 132). The predetermined specified range is a range having a certain width centered on a PWM frequency value specified in advance to be used in PWM communication between the ECU 42 and the control circuit 36. As a result, when it is determined that the PWM frequency is not within the predetermined specified range, it is determined that an SI abnormality due to noise superimposition or the like has occurred, and execution of the failure diagnosis of the drive device 10 is prohibited (step 134). ). On the other hand, if it is determined that the PWM frequency is within the predetermined specified range, it is determined that SI abnormality due to noise superimposition or the like has not occurred, and execution of failure diagnosis of the drive device 10 is permitted (step 136). .

  After the processing of step 110 shown in FIG. 4, the control circuit 36 determines whether or not the failure diagnosis of the drive device 10 is permitted based on the processing results of steps 134 and 136 shown in FIG. 5. (Step 112). As a result, when it is determined that the failure diagnosis of the drive device 10 is prohibited, the routine processing shown in FIG. On the other hand, when it is determined that the failure diagnosis of the drive device 10 is permitted, a process for determining whether or not the failure diagnosis of the drive device 10 can be performed is performed (step 114).

  As such a feasibility determination, the control circuit 36 first turns off all the pair of switching elements Su, Sd of all phases in the driving apparatus 10 (step 140 shown in FIG. 6). Then, the switching element Su on the + B line 32 side of the pair of switching elements Su, Sd of one phase (corresponding phase) arbitrarily selected from the three phases U, V, W is turned on (step 142), and Of the pair of switching elements Su and Sd for each phase (non-corresponding phase) different from the corresponding phase, the switching element Sd on the GND line 34 side is sequentially turned on (step 144). For example, the U-phase switching element Su is turned on and the V-phase switching element Svd is turned on. Thereafter, the V-phase switching element Svd is turned off and the W-phase switching element Svd is turned on while the U-phase switching element Suu is turned on. Turn on.

  The control circuit 36 determines whether or not the output voltages Vu, Vv, Vw of the corresponding phase detected based on the output of the voltage detection circuit 40 are the + B potential after performing the processing of the above steps 140 to 144. (Step 146). When the switching element Su on the + B line 32 side of the corresponding phase is on, the output voltages Vu, Vv, and Vw of the corresponding phase become + B potential unless the driving device 10 has failed, while the driving device 10 If a failure occurs, the potential may be different from the + B potential.

  If the control circuit 36 determines in step 146 that the output voltages Vu, Vv, and Vw of the corresponding phase are the + B potential, next, in step 144, the non-switched element Sd on the GND line 34 side is turned on. It is determined whether or not the output voltages Vu, Vv, and Vw detected based on the output of the voltage detection circuit 40 in the corresponding phase are the GND potential (step 148). When the switching element Sd on the GND line 34 side of the non-corresponding phase is turned on, the output voltages Vu, Vv, Vw of the corresponding phase are set to the GND potential unless the driving device 10 has failed. If 10 is out of order, the potential may be different from the GND potential.

  If the control circuit 36 determines in step 148 that the output voltages Vu, Vv, and Vw of the non-corresponding phases are the GND potential, the control circuit 36 then switches the drive device 10 based on the output of the current detection circuit 38. It is determined whether or not the current Iuvw is flowing from the + B line 32 side toward the GND line 34 side (step 150). Since the failure diagnosis of the drive device 10 is performed without the brushless motor 14 being connected to the drive device 10, the current Iuvw does not flow unless the drive device 10 has failed, while the drive device 10 has failed due to a short circuit. If it is, it may flow.

  When the control circuit 36 determines that the current Iuvw does not flow in step 150, the control circuit 36 selects all the three phases U, V, and W as the corresponding phases and then performs steps 142 to 150 for each phase. It is determined whether or not the process is completed (step 152). As a result, when it is determined that all the three phases U, V, W are not selected as the corresponding phase and the processing of steps 142 to 150 is not completed for at least one of the phases, The corresponding phase is changed by selecting a phase that has not been selected as the corresponding phase among the three phases U, V, and W as the corresponding phase (step 154). When the relevant phase is changed, the processing after Step 140 is repeated for the relevant phase after the change.

  On the other hand, if it is determined in step 152 that all three phases U, V, and W are selected as the corresponding phases and it is determined that the processing in steps 142 to 150 has been completed for each phase, failure diagnosis of the drive device 10 is performed. Is determined to be possible, and the execution is permitted (step 156).

  When the control circuit 36 determines that the output voltages Vu, Vv, Vw of the corresponding phase are not the + B potential in the step 146, the control circuit 36 determines that the output voltages Vu, Vv, Vw of the non-corresponding phase are not the GND potential in the step 148. If it is determined in step 150 that the current Iuvw is flowing, next, all the pair of switching elements Su, Sd of all phases in the driving device 10 are turned off (step 158), and then the driving device It is determined that the failure diagnosis 10 cannot be performed, and the execution is prohibited (step 160).

  After the process of step 114 shown in FIG. 4, the control circuit 36 determines whether or not the failure diagnosis of the drive device 10 is permitted based on the process results of steps 156 and 160 shown in FIG. 6. (Step 116). As a result, if it is determined that failure diagnosis of the drive device 10 is prohibited, it is then determined that a failure has occurred in the drive device 10 (step 118). When the control circuit 36 determines that a failure has occurred in the drive device 10, the control circuit 36 notifies the ECU 42 via the communication line 44 that the drive device 10 has failed. Also good.

  On the other hand, if the control circuit 36 determines that the failure diagnosis of the drive device 10 is permitted, then the control circuit 36 tests the output voltages Vu, Vv, Vw of the drive terminals 18U, 18V, 18W of the drive device 10. Processing is performed (step 120).

  As such test processing, the control circuit 36 first determines whether or not the phase to be subjected to the failure diagnosis determined based on the duty value by PWM communication from the ECU 42 is the U phase (step shown in FIG. 7). 170). As a result, when it is determined that the phase on which the failure diagnosis is to be performed is the U phase, the pair of U-phase switching elements Suu and Sud are alternately turned on and off (step 172). At this time, the U-phase switching elements Suu and Sud by the control circuit 36 are turned on and off at a predetermined duty value (for example, 50%).

  When no failure has occurred in the U phase of the driving apparatus 10, a desired voltage corresponding to the duty value to the switching elements Suu and Sud appears at the U phase drive terminal 18U. For example, when the duty value is 50%, a voltage having an intermediate value (+ B / 2) between the potential + B of the + B line 32 and the potential GND of the GND line 34 appears at the U-phase drive terminal 18U. On the other hand, when a failure such as an open or short occurs in the U phase of the driving device 10, a voltage different from a desired voltage corresponding to the duty value to the switching elements Suu and Sud at the U phase driving terminal 18U. Appears.

  Therefore, when the control circuit 36 executes the processing of step 172, the tester 54 connected to the driving device 10 measures the output voltage Vu of the driving terminal 18U with the voltage measuring circuit 56 as a reference based on the GND potential (step). 174).

  If the control circuit 36 determines in step 170 that the phase on which failure diagnosis is to be performed is not the U phase, the control circuit 36 then determines whether or not the phase on which failure diagnosis is to be performed is the V phase. (Step 176). As a result, if it is determined that the phase on which the failure diagnosis is to be performed is the V phase, the pair of switching elements Svu and Svd for the V phase are then alternately turned on and off (step 178). At this time, the V-phase switching elements Svu and Svd by the control circuit 36 are turned on and off at a predetermined duty value (for example, 50%).

  When no failure has occurred in the V phase of the drive device 10, a desired voltage corresponding to the duty value to the switching elements Svu and Svd appears at the V phase drive terminal 18V. For example, when the duty value is 50%, a voltage having an intermediate value (+ B / 2) between the potential + B of the + B line 32 and the potential GND of the GND line 34 appears at the V-phase drive terminal 18V. On the other hand, when a failure such as an open or short occurs in the V phase of the drive device 10, a voltage different from a desired voltage corresponding to the duty value to the switching elements Suu and Sud is applied to the V phase drive terminal 18V. Appears.

  Therefore, when the control circuit 36 executes the processing of step 178, the tester 54 connected to the driving device 10 measures the output voltage Vv of the driving terminal 18V with reference to the GND potential in the voltage measuring circuit 56 (step). 180).

  Further, if the control circuit 36 determines in step 176 that the phase for which failure diagnosis is to be performed is not the V phase, the control circuit 36 can determine that the phase for which failure diagnosis is to be performed is the W phase. The pair of switching elements Swu and Swd are alternately turned on and off (step 182). At this time, the W-phase switching elements Swu and Swd by the control circuit 36 are turned on and off at a predetermined duty value (for example, 50%).

  When no failure has occurred in the W phase of the drive device 10, a desired voltage corresponding to the duty value to the switching elements Swu and Swd appears at the W phase drive terminal 18W. For example, when the duty value is 50%, a voltage having an intermediate value (+ B / 2) between the potential + B of the + B line 32 and the potential GND of the GND line 34 appears at the W-phase drive terminal 18W. On the other hand, when a failure such as an open or short occurs in the W phase of the driving device 10, a voltage different from a desired voltage corresponding to the duty value to the switching elements Swu and Swd at the W phase drive terminal 18W. Appears.

  Therefore, when the control circuit 36 executes the processing of step 182 described above, the tester 54 connected to the driving device 10 measures the output voltage Vw of the driving terminal 18W with reference to the GND potential in the voltage measuring circuit 56 (step). 184).

  The tester 54 determines whether or not the output voltages Vu, Vv, Vw measured in steps 174, 180, 184 are within a predetermined specified range (step 122). The predetermined specified range is a range having a certain width centered on a desired voltage corresponding to a duty value in which the control circuit 36 turns on and off the pair of switching elements Su and Sd of each phase. As a result, when it is determined that the measured output voltages Vu, Vv, and Vw are within a predetermined specified range, that is, not a value that is more than a predetermined distance from the desired voltage, it is determined that the drive device 10 has not failed. . On the other hand, when it is determined that the measured output voltages Vu, Vv, and Vw are not within the predetermined specified range, that is, not a value that is not less than a predetermined value from the above-described desired voltage, it is determined that a failure has occurred in the drive device 10 ( Step 118).

  As described above, in this embodiment, it is possible to perform a diagnosis as to whether or not a failure has occurred in the drive device 10 in accordance with an instruction from the scan tool 50 connected to the ECU 42. Specifically, in accordance with an instruction from the scan tool 50, first, the control circuit 36 turns on the switching element Su on the + B line 32 side of the pair of switching elements Su and Sd of one phase in the driving device 10, and When the switching element Sd on the GND line 34 side is turned on among the pair of switching elements Su and Sd in other phases, the output voltages Vu, Vv, Vw of the phase in which the switching element Su on the + B line 32 side is turned on Is the + B potential, whether the output voltage Vu, Vv, Vw of the phase in which the switching element Sd on the GND line 34 side is turned on is the GND potential, and the drive device 10 from the + B line 32 side. It is determined whether or not the current Iuvw flows toward the GND line 34, and whether or not the failure diagnosis of the drive device 10 can be performed based on the determination result. It can be constant.

  Specifically, the output voltage Vu, Vv, Vw of the phase in which the switching element Su on the + B line 32 side is turned on is the + B potential, and the phase in which the switching element Sd on the GND line 34 side is turned on. When the output voltages Vu, Vv, and Vw are determined to be the GND potential and the current Iuvw is not flowing, it is determined that the failure diagnosis of the drive device 10 can be performed. On the other hand, the output voltages Vu, Vv, Vw of the phase in which the switching element Su on the + B line 32 side is turned on are not the + B potential, and the output voltages Vu, Vv, Vw of the phase in which the switching element Sd on the GND line 34 side are turned on. When it is determined that the potential is not the GND potential or the current Iuvw is flowing, it is determined that the failure diagnosis of the drive device 10 cannot be performed, and the drive device 10 is determined to have a failure.

  In this respect, the switching element Su on the + B line 32 side of the pair of switching elements Su and Sd of one phase in the driving device 10 is turned on, and the GND line 34 of the pair of switching elements Su and Sd of the other phase is turned on. When the switching device Sd on the side is turned on, the current condition Iuvw does not flow from the + B line 32 side to the GND line 34 side when the driving device 10 is turned on is set as an execution condition of the fault diagnosis of the driving device 10. If the current Iuvw is flowing, it can be determined that the drive device 10 has failed.

  In such a configuration, when the failure diagnosis of the drive device 10 is performed, the motor terminals 16U, 16V, and 16W of the brushless motor 14 are connected to the motor side connector 20 of the drive device 10, that is, the drive terminals 18U, 18V, and 18W. Is unnecessary. That is, based on whether or not the current Iuvw flows from the + B line 32 side to the GND line 34 side when the switching elements Su and Sd are turned on without connecting the brushless motor 14 to the drive device 10. Thus, failure diagnosis of the drive device 10 can be performed.

  If the brushless motor 14 is not connected to the driving device 10 at the time of failure diagnosis of the driving device 10 based on the presence or absence of the current Iuvw, the current induced by the rotation of the brushless motor 14 does not flow to the driving device 10. The failure diagnosis of the drive device 10 is not affected by the induced voltage generated by the rotation of the brushless motor 14. For this reason, according to the present embodiment, the failure diagnosis of the drive device 10 based on the presence / absence of the current Iuvw can be accurately performed. Further, according to the present embodiment, since it is not necessary to guarantee that the rotation of the brushless motor 14 is stopped when diagnosing the failure of the drive device 10 based on whether or not the current Iuvw is distributed, the rotation is stopped. It is not necessary to provide components such as a rotation sensor and detection circuit for detecting the rotation, and it is not necessary to execute control for realizing the rotation stop, thereby reducing costs. Can do.

  Therefore, according to the failure diagnosis device 12 of the drive device 10 of the present embodiment, the failure diagnosis of the drive device 10 based on the presence / absence of the current Iuvw can be accurately performed with a simple and inexpensive configuration.

  Further, in this embodiment, when it is determined that the failure diagnosis can be performed as a result of the control circuit 36 determining whether or not the failure diagnosis of the drive device 10 can be performed according to the instruction from the scan tool 50, Thereafter, the control circuit 36 causes the tester 54 to measure the output voltages Vu, Vv, Vw of each phase of the driving device 10 while alternately turning on and off the pair of switching elements Suu, Sud for each phase at a predetermined duty value. A failure diagnosis of the device 10 can be performed.

  Specifically, the measured output voltages Vu, Vv, Vw are applied to the test terminals 54 connected to the drive terminals 18U, 18V, 18W of the drive device 10, that is, the motor-side connector 20, according to the predetermined duty values. If it is determined that it is in the vicinity (that is, within a predetermined specified range), it is determined that no failure has occurred in the drive device 10. On the other hand, if it is determined that the measured output voltages Vu, Vv, Vw are not in the vicinity of the desired voltage corresponding to the predetermined duty value (that is, within a predetermined specified range), the drive device 10 has a failure such as an open or short circuit. It is determined that has occurred.

  In this respect, failure diagnosis of the drive device 10 can be performed while the tester 54 is connected to the drive terminals 18U, 18V, 18W to which the brushless motor 14 is normally connected, that is, the motor-side connector 20, instead of the brushless motor 14. . In such a configuration, since it is not necessary to notify the failure information from the drive device 10 to the ECU 42 in performing the failure diagnosis of the drive device 10, a communication function in the drive device 10 or the ECU 42 is used for the notification. It is not necessary to provide communication lines, terminals, etc., and such failure diagnosis can be realized with a simple and inexpensive configuration.

  In this embodiment, the tester 54 is connected to the driving device 10 via the motor-side connector 20 and measures the output voltages Vu, Vv, Vw of the driving device 10 based on the potential E of the ground terminal 22. The potential E of the ground terminal 22 is the same as the reference potential (GND potential) of the driving device 10. In this regard, according to the present embodiment, since the vehicle earth or the like of the vehicle is not used as the reference potential of the tester 54, the voltage measurement result of the tester 54 includes a voltage drop due to the earth resistance or contact resistance associated with the use of the body earth. The measurement accuracy of the output voltages Vu, Vv, Vw of the driving device 10 by the tester 54 can be improved.

  Further, the tester 54 measures the output voltages Vu, Vv, Vw of the drive device 10 using the drive terminals 18U, 18V, 18W and the ground terminal 22 that are provided in the vicinity of the motor-side connector 20 of the drive device 10. To do. For this reason, it is possible to easily measure the output voltages Vu, Vv, Vw of the driving device 10 by the tester 54.

  In the present embodiment, the ECU 42 issues a failure diagnosis execution instruction to the drive device 10 by PWM communication using the communication line 44 in accordance with an instruction from the scan tool 50. The duty value by the PWM communication used when the ECU 42 instructs the drive device 10 to execute the failure diagnosis is different from the normal use range by the PWM communication used when the ECU 42 instructs the drive device 10 to rotate the brushless motor 14. Use the area. Therefore, according to such a configuration, the motor rotation instruction and the failure diagnosis execution instruction from the ECU 42 to the drive device 10 can be performed via the common communication line 44, so that the configuration is simplified and the cost is reduced. be able to.

  By the way, when the engine is rotating, noise may be superimposed on PWM communication from the ECU 42 to the driving device 10. When noise is superimposed on the PWM communication, the duty value by the PWM communication changes from a desired value due to the presence of the noise, and as a result, the failure diagnosis of the drive device 10 may be erroneously determined. On the other hand, in the present embodiment, the ECU 42 issues a failure diagnosis execution instruction to the drive device 10 only when the engine is stopped, and not when the engine is rotating. Therefore, according to the present embodiment, the failure diagnosis of the drive device 10 can be suppressed from being performed at a timing during engine rotation that may cause a false diagnosis, and the failure diagnosis of the drive device 10 can be performed with high accuracy. It can be carried out.

  In the present embodiment, the control circuit 36 of the drive device 10 calculates the PWM frequency of the PWM communication from the ECU 42. When the PWM frequency is within a predetermined specified range, the drive device 10 performs a failure diagnosis. On the other hand, if the PWM frequency is not within a predetermined specified range, the failure diagnosis of the drive device 10 is prohibited. Therefore, according to the present embodiment, when the PWM communication from the ECU 42 to the driving device 10 is performed with a deviation from the PWM frequency within a predetermined specified range due to noise superposition or the like, the driving device Therefore, the failure diagnosis of the drive device 10 can be prevented from being erroneously performed.

  In the above embodiment, the control circuit 36 of the driving device 10 performs the steps in the routine shown in FIG. 6 in a state where the motor terminals 16U, 16V, and 16W of the brushless motor 14 are not connected to the driving terminals 18U, 18V, and 18W. In the “switch control means” described in the claims that the processing of 142 and 144 is executed, it is claimed that the control circuit 36 executes steps 116 and 118 in the routine shown in FIG. In the “first diagnostic means” and “first step” described in the above-mentioned range, the tester 54 performs the processing of step 122 in the routine shown in FIG. 4 after the processing of steps 174, 180, and 184 in the routine shown in FIG. The execution corresponds to “second diagnostic means” and “second step” recited in the claims.

  Further, the + B line 32 is described in the “power supply + line” described in the claims, the GND line 34 is described in the “power supply-line” described in the claims, and the control circuit 36 is described in the claims. The scanning tool 50 corresponds to the “control unit” and the “instruction means” recited in the claims.

DESCRIPTION OF SYMBOLS 10 Brushless motor drive device 12 Failure diagnosis device 14 Motor 16 Motor terminal 18 Drive terminal 26 + B terminal 28 GND terminal 32 + B line 34 GND line 36 Control circuit 38 Current detection circuit 40 Voltage detection circuit 42 Electronic control unit (ECU)
48 Engine rotation sensor 50 Scan tool 54 Tester

Claims (7)

A plurality of drive terminals that can be connected to a plurality of phase motor terminals of the brushless motor, and a DC power supply + line and a power supply-line that are provided corresponding to each phase of the brushless motor are connected in series. A device for diagnosing a failure of a brushless motor drive device having a pair of switching elements,
In a state where the motor terminals of the brushless motor are not connected to the plurality of drive terminals, the switching element on the power source + line side among the pair of switching elements of one phase is turned on, and the pair of pairs of other phases Switch control means for turning on the switching element on the power source-line side among the switching elements;
When the switch control by the switch control means is performed, the brushless motor driving device is driven based on whether or not a current flows from the power source + line side to the power source -line side when the brushless motor driving device flows. First diagnostic means for diagnosing whether or not the device is faulty;
A failure diagnosis device for a brushless motor driving device.   When the pair of switching elements of each phase are alternately turned on and off at a predetermined duty ratio after the first diagnosis means diagnoses that the brushless motor drive device has not failed because the current does not flow. Second diagnostic means for diagnosing whether or not the brushless motor driving device is out of order based on whether or not a voltage generated between the pair of switching elements is a value corresponding to the predetermined duty ratio; The failure diagnosis device for a brushless motor drive device according to claim 1, comprising: The switch control unit is connected to an electronic control unit that instructs rotation of the brushless motor by PWM communication, and controls on / off of each switching element of the brushless motor driving device according to an instruction from the electronic control unit. Included in the part,
3. The brushless motor drive device according to claim 1, further comprising an instruction unit that is connected to the electronic control unit and instructs the electronic control unit to perform a failure diagnosis of the brushless motor drive device. Fault diagnosis device. The electronic control unit performs PWM using a duty value in a predetermined use range different from a normal use range used during normal use of the brushless motor drive device when execution of the failure diagnosis is instructed by the instruction means. Instructing the control unit to perform the fault diagnosis by communication,
The said control part performs the process for implementing the said fault diagnosis as said switch control means, when the said duty value by the PWM communication from the said electronic control unit is in the said predetermined use range. 4. A failure diagnosis device for a brushless motor drive device according to 3. The brushless motor driving device is mounted on a vehicle driven by engine rotation,
5. The failure diagnosis device for a brushless motor drive device according to claim 4, wherein the electronic control unit instructs the control unit to perform the failure diagnosis only while the engine rotation is stopped. A plurality of drive terminals that can be connected to a plurality of phase motor terminals of the brushless motor, and a DC power supply + line and a power supply-line that are provided corresponding to each phase of the brushless motor are connected in series. A method of diagnosing a failure of a brushless motor drive device having a pair of switching elements,
In a state where the motor terminals of the brushless motor are not connected to the plurality of drive terminals, the switching element on the power source + line side among the pair of switching elements of one phase is turned on, and the pair of pairs of other phases Based on whether or not the current flows from the power source + line side to the power source-line side when the switching element on the power source-line side among the switching elements is turned on, A failure diagnosis method for a brushless motor drive device, comprising a first step of diagnosing whether or not the brushless motor drive device has failed.   In the first step, when it is diagnosed that the brushless motor drive device has not failed because the current does not flow, the pair of switching elements of each phase are alternately turned on / off at a predetermined duty ratio. A second step of diagnosing whether or not the brushless motor driving device is out of order based on whether or not a voltage generated between the pair of switching elements is a value corresponding to the predetermined duty ratio; The failure diagnosis method for a brushless motor drive device according to claim 6.

Images