JP2009229291A - Sr motor drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To distinguish a disconnection failure of each phase coil winding in an SR motor from a ground short-circuit failure for detection with a simple configuration. <P>SOLUTION: For respective phase coil windings 3u, 3v, 3w of the SR motor 1 where a supply voltage VB is supplied to a connection point YP of Y connection, in an SR motor drive 20 having a connection terminal 5 to which its terminal is connected and a drive transistor 15, a pull-down resistor R2 is connected between the other end of a resistor R1 of which one end is connected to each connection terminal 5 and ground potential, and a pull-up resistor R3 is connected to the other end of the resistor R1 via a diode D1. Then, a microcomputer 11 monitors a voltage VM at the connection point of the resistors R1, R2 when the drive transistor 15 is off for each phase coil winding 3, determines the voltage VM to be abnormal when it is lower than a normal determination value, applies a voltage VP for pull-up to the pull-up resistor R3, and discriminates whether failure in the winding 3 is disconnection or ground short-circuit based on the voltage VM in that state. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an apparatus for driving an SR motor, and more particularly to a technique for detecting an abnormality in each phase winding of the SR motor.

  Conventionally, for example, in a vehicle, an SR motor (switched reluctance motor) is used as an actuator for operating a shift range switching mechanism of an automatic transmission (see, for example, Patent Document 1).

Here, FIG. 9 shows a configuration example of an apparatus for driving the SR motor.
In the SR motor drive device 100 shown in FIG. 9, the end portions of the windings 3u, 3v, 3w of the respective phases (U phase, V phase, W phase) of the SR motor 1 that are Y-connected (star-connected) are respectively provided. To turn on the motor power relay 7 that supplies the battery voltage VB as the power supply voltage to the connection terminals 5u, 5v, 5w to be connected and the connection points (Y connection points) YP between the windings 3u, 3v, 3w. The power supply control transistor 9 and the microcomputer 11 that performs processing for controlling the SR motor 1 are provided.

  Note that the lowercase letters u, v, and w that form part of the code indicate whether the corresponding code corresponds to the U phase, V phase, or W phase. For example, the winding 3u is a U-phase winding, and the connection terminal 5u is a connection terminal to which the U-phase winding 3u is connected. Further, in the following description, when it is not particularly distinguished which phase corresponds to, a code obtained by deleting the lowercase letters u, v, and w is used as the code.

  Furthermore, the SR motor driving device 100 is for winding energization provided in series between the connection terminal 5 to which the winding 3 is connected and the ground potential for each of the phase windings 3u, 3v, 3w. A drive transistor (N-channel MOSFET in this example) 15 as a switching element and two resistors R1 and R2 for causing the microcomputer 11 to monitor the voltage of the connection terminal 5 are provided. One resistor R1 is an input protection resistor having one end connected to the connection terminal 5 and the other end connected to the A / D conversion input port of the microcomputer 11, and the other resistor R2 is a resistor This is a pull-down resistor provided between the end of R1 on the microcomputer 11 side and the ground potential.

  In this example, a current detection resistor 17 for detecting the current flowing through the drive transistor 15 is provided on the downstream side of the drive transistor 15. When the potential difference generated in the current detection resistor 17 exceeds a specified value, an overcurrent detection signal is output from the overcurrent detection circuit 19 including a differential amplifier to the microcomputer 11.

  In FIG. 9, the drive transistor 15, resistors R1 and R2, current detection resistor 17 and overcurrent detection circuit 19 are shown only for the U phase, but similarly provided for each of the V phase and the W phase. It has been.

  In such an SR motor driving apparatus 100, when the microcomputer 11 operates the SR motor 1, the motor power supply signal, which is a drive signal for the power supply control transistor 9, is set to an active level (low in this example). When the power supply control transistor 9 is turned on, a current is passed through the coil of the motor power relay 7 to turn on the motor power relay 7. Then, the battery voltage VB is supplied from the motor power supply relay 7 to the connection point YP between the windings 3u, 3v, 3w.

  The microcomputer 11 detects the rotational position of the rotor (not shown) of the SR motor 1 based on a signal from a rotary encoder (not shown) provided in the SR motor 1, and based on the detected rotational position. The SR transistors 1 are operated by sequentially switching the windings 3 of the phase through which the current flows by switching on the driving transistors 15 of each phase sequentially. Each phase driving transistor 15 is turned on / off by a motor phase driving signal from the microcomputer 11. When the overcurrent detection signal from the overcurrent detection circuit 19 is input, the microcomputer 11 forcibly turns off the drive transistor 15 corresponding to the overcurrent detection circuit 19 to protect it from the overcurrent.

  Furthermore, the microcomputer 11 performs the following abnormality detection process in order to detect abnormality of each phase winding 3u, 3v, 3w. Here, the case where the winding 3 to be detected for abnormality is a U-phase winding 3u will be described as an example, but the same applies to the V-phase and W-phase windings 3v and 3w.

  First, when the motor power supply relay 7 is turned on and the drive transistor 15 corresponding to the U phase is turned off, the resistors R1 and R2 corresponding to the U phase (that is, provided for the connection terminal 5u) are provided. Monitoring is performed by A / D converting the voltage VMu (hereinafter also referred to as monitor voltage) VMu of the connection point of the resistors R1 and R2).

  The microcomputer 11 determines that the monitor voltage VMu is normal if the monitor voltage VMu is equal to or greater than the specified value Vth. It is determined that a short-circuit failure (hereinafter, also simply referred to as a ground short-circuit or a ground short-circuit failure) has occurred, and the power supply to the SR motor 1 is stopped by turning off the motor power supply relay 7 so that the subsequent SR motor 1 Stop driving.

  That is, when the motor power relay 7 is on and the U-phase compatible drive transistor 15 is off, if the winding 3u is normal, the monitor voltage VMu is greater than 0V, but the winding 3u is disconnected. If it is or is short-circuited to the ground potential, the monitor voltage VMu becomes 0 V. Therefore, in the abnormality detection process, the voltage drop phenomenon is detected as an abnormality.

Note that the resistance value of the winding 3 is a negligible value compared to the resistance values of the resistors R1 and R2, and can be regarded as zero. For this reason, the specified value Vth is set to a value equal to or smaller than an assumed minimum value (designed minimum value) in a normal state of a value obtained by dividing the battery voltage VB by the resistor R1 and the resistor R2, and larger than 0V. Has been. Therefore, if the winding 3u is normal, “VMu ≧ Vth” is satisfied. However, if the winding 3u is disconnected or short-circuited to the ground potential at the position (a) or (b) in FIG. 9, “VMu < Vth ”and the microcomputer 11 determines that the abnormality has occurred. Further, when the microcomputer 11 determines that the windings 3u, 3v, 3w of all phases are abnormal, it can determine that a disconnection or a ground short-circuit has occurred at the position (c) in FIG. .
JP 2000-170905 A

  In the above-described conventional SR motor driving apparatus 100, it is possible to detect the occurrence of disconnection or ground short-circuit in the windings 3u, 3v, 3w of each phase, but it is not possible to determine which one has occurred. .

  Therefore, in the conventional apparatus 100, when any one phase winding 3 is disconnected, the SR motor 1 can be operated by controlling the energization to the other two phase windings 3. However, since the failure mode may be a ground short-circuit, when an abnormality is detected, the power supply to the SR motor 1 is cut off for safety and the driving of the SR motor 1 must be stopped. .

  For example, when a current detection circuit capable of detecting current flowing from the connection point YP of the Y connection to each of the windings 3u, 3v, 3 is additionally provided and the winding 3 of any phase is determined to be abnormal In addition, if the current detection value of the current detection circuit corresponding to the phase is 0, it is determined that the abnormality is a disconnection, and if the current detection value is not 0, it is determined that the abnormality is a ground short circuit. It is also possible to adopt However, such a method complicates the circuit configuration and causes a significant cost increase.

  The present invention has been made in view of such problems, and an object of the present invention is to provide an SR motor drive device that can detect and detect a disconnection failure and a ground short-circuit failure of each phase winding of an SR motor with a simple configuration. .

  The SR motor drive device according to claim 1 includes: a connection terminal connected to the other end of each winding of each phase winding of the SR motor to which a power supply voltage is supplied to one end; the connection terminal and the ground potential; And a switching element that flows in the winding when turned on. Then, the SR motor is operated by controlling each switching element (that is, each switching element that supplies a current to each phase winding).

  Further, the SR motor driving device includes, for each of the phase windings, a voltage monitor signal line connected to the connection terminal, a pull-down resistor provided between the ground potential and the voltage monitor signal line, A pull-up resistor provided between the pull-up voltage higher than the potential and the voltage monitoring signal line is provided, and an abnormality detecting means is provided.

  The abnormality detecting means for each phase winding operates when the switching element of the phase corresponding to itself (hereinafter referred to as the relevant phase) is off, and is connected to the connection terminal of the relevant phase. Based on the voltage of the voltage monitoring signal line, the disconnection failure of the winding of the corresponding phase and the short-circuit failure to the ground potential are distinguished and detected.

  That is, when a winding of any phase is short-circuited to the ground potential, the voltage at the connection terminal of that phase becomes 0 V (= ground potential), whereas when the winding is disconnected, The voltage at the connection terminal is higher than 0 V due to the action of the pull-up resistor. Therefore, the voltage of the voltage monitoring signal line is higher when the wire is disconnected than when the winding is short-circuited to the ground potential. In addition, when the winding is normal, the voltage monitor signal line is applied not only to the voltage by the pull-up resistor but also to the voltage monitor signal line through the winding. The voltage is higher than the voltage when the winding is disconnected. Therefore, the abnormality detection means can determine whether or not the winding is normal based on the voltage of the voltage monitoring signal line, and can detect and detect the disconnection failure of the winding and the ground short-circuit failure.

  According to such an SR motor driving device, it is possible to distinguish and detect a disconnection failure and a ground short-circuit failure of each phase winding of the SR motor with a simple configuration without adding a current detection circuit as described above. Can do.

  Next, in the SR motor driving device according to claim 2, in the SR motor driving device according to claim 1, the abnormality detecting means applies the pull-up voltage to the pull-up resistor and stops applying the pull-up voltage. Are to be switched.

  According to this configuration, unless the disconnection failure of the winding and the ground short-circuit failure are detected separately, the pull-up voltage is not applied to the pull-up resistor (that is, the pull-up resistor is disabled). It is possible to cause a voltage reflecting the voltage of the connection terminal to appear as it is in the voltage monitor signal line without causing an increase in voltage due to the pull-up resistor. For this reason, the voltage of the voltage monitor signal line can be fed back to the control of the SR motor. For example, adjustment control such as changing the on-time of the switching element according to the voltage of the voltage monitoring signal line when the switching element is on or off can be performed correctly.

  By the way, the abnormality detection means in the SR motor drive device of claim 2 can be configured as described in claim 3, for example. That is, the abnormality detection means determines whether the winding is normal or abnormal based on the voltage of the voltage monitor signal line in a state where the application of the pull-up voltage to the pull-up resistor is stopped, and is abnormal. Is applied, a pull-up voltage is applied to the pull-up resistor, and based on the voltage of the voltage monitor signal line, it is determined whether the winding abnormality is a disconnection failure or a short-circuit failure to the ground potential. It is the structure of doing.

  With this configuration, the pull-up resistor is disabled until the winding is determined to be abnormal, and the winding is determined to be abnormal. The pull-up resistor can be made effective only when it is determined whether or not. Therefore, the period during which the pull-up resistor is valid can be minimized.

  Next, an SR motor drive device according to a fourth aspect is the SR motor drive device according to any one of the first to third aspects, wherein when the disconnection failure of any one phase winding is detected by the abnormality detection means, Among them, the degenerate operation for operating the SR motor is performed by controlling only the switching elements corresponding to the windings of the normal phase.

  According to such an SR motor driving device, even if any one phase winding is disconnected, the SR motor can be operated by energizing the remaining normal phase windings. It is possible to increase the probability that the SR motor can operate (operation continuation probability for abnormality).

  Next, an SR motor drive device according to a fifth aspect is the SR motor drive device according to the fourth aspect, further comprising abnormality notification means. Then, the abnormality notification means notifies the user of the SR motor that an abnormality has occurred when the degenerate operation is performed. The SR motor user is a user of a system in which the SR motor is used as a power source, or a user of an object on which the system is mounted.

According to this configuration, it is possible to notify the user of the occurrence of an abnormality and prompt treatment such as repair. For this reason, it is possible to prevent the state in which the degenerate operation is performed from continuing.
Next, the SR motor drive device according to claim 6 is the SR motor drive device according to claims 1 to 5, in the case where a short circuit failure to the ground potential of any one phase winding is detected by the abnormality detection means, Supply of power supply voltage to each phase winding is cut off.

  According to such an SR motor driving device, it is possible to reliably prevent an excessive current flowing when the winding is short-circuited to the ground potential. For this reason, it is possible to prevent the power source generation source from being consumed.

  Next, an SR motor driving device according to a seventh aspect of the present invention is the SR motor driving device according to the sixth aspect, further comprising short-circuit failure notification means. The short-circuit failure notification means notifies the SR motor user that a short-circuit failure to the ground potential of the winding has occurred when the supply of the power supply voltage is interrupted.

According to this configuration, since it is possible to notify the user that a ground short-circuit fault has occurred in the winding, it is easy to identify the fault location when repairing.
Next, in the SR motor drive device according to claim 8, in the SR motor drive device according to claims 1 to 7, the abnormality detection means is a short circuit for determining that a short circuit failure to the ground potential has occurred in the winding. It has a failure determination value and a disconnection failure determination value that is larger than the short-circuit failure determination value and for determining that a disconnection failure has occurred in the winding.

Then, the abnormality detection means determines that an indefinite abnormality has occurred in the winding if the voltage of the voltage monitor signal line is a voltage between the short-circuit failure determination value and the disconnection failure determination value.
According to this configuration, the state in which the winding is not completely at ground potential but is short-circuited with a certain degree of impedance (so-called rare short state) is further distinguished from ground short-circuit failure and disconnection failure. It can be detected as an abnormality.

  Next, the SR motor drive device according to claim 9 is the SR motor drive device according to claim 8, wherein when the indefinite abnormality of any one-phase winding is detected by the abnormality detection means, each switching element is turned on. It is controlled to check whether the SR motor operates.

  According to this configuration, when the degree of rare short to the ground potential of the winding is light and the SR motor can be operated, the SR motor can be continuously operated. For this reason, the operation continuation probability for an abnormality can be increased.

  In the SR motor drive device according to claim 9 as well, in order to prevent the operation of the SR motor from continuing in a state where an abnormality has occurred, the abnormality notification means similar to the SR motor drive device according to claim 5 is used. It is preferable to provide (means for notifying the user of the SR motor that an abnormality has occurred).

Hereinafter, an SR motor driving apparatus according to an embodiment to which the present invention is applied will be described.
[First Embodiment]
First, FIG. 1 is a configuration diagram showing the configuration of the SR motor drive device 20 of the first embodiment. In FIG. 1, the same components as those in FIG. 9 are denoted by the same reference numerals as those in FIG. In addition, the SR motor drive device 20 of the present embodiment is provided in a vehicle, for example, and operates the SR motor 1 in accordance with the operation of the shift lever by the driver, so that the automatic transmission is driven by the power of the SR motor 1. The shift range is switched.

  Compared with the conventional SR motor driving device 100 shown in FIG. 9, the SR motor driving device 20 has a pull-up resistor R3 and a diode D1 for each of the phase windings 3u, 3v, 3w in terms of hardware. The point that is added is different. In FIG. 1, the pull-up resistor R3 and the diode D1 are shown only for the U phase, but are similarly provided for the V phase and the W phase.

  The cathode of the diode D1 is connected to the connection point of the resistors R1 and R2, and one end of the pull-up resistor R3 is connected to the anode of the diode D1. The other end of the pull-up resistor R3 is connected to the output port of the microcomputer 11, and the pull-up voltage VP is applied from the output port. The pull-up voltage VP from the microcomputer 11 is the same voltage as the constant operating voltage VC supplied to the microcomputer 11 from a power supply circuit (not shown), and is 5V in this embodiment.

In this configuration, the following operation is obtained for each of the phase windings 3u, 3v, 3w.
First, assuming that the winding 3 is normal when the driving transistor 15 is off and the motor power relay 7 is on and the pull-up voltage VP is not applied to the pull-up resistor R3, the resistance value of the winding 3 is assumed to be normal. Is ignored, the voltage Vn obtained by dividing the battery voltage VB by the resistors R1 and R2 appears as the monitor voltage VM, while the winding 3 is disconnected or shorted to the ground potential. Then, since the monitor voltage VM becomes 0 V due to the pull-down action of the resistor R2, it is detected based on the monitor voltage VM that either a disconnection failure or a ground short-circuit failure has occurred in the winding 3. Can do. Note that the resistance value of the winding 3 is negligible because it is sufficiently smaller than the resistance values of the resistors R1 to R3.

  If the winding 3 is disconnected when the driving transistor 15 is off and the pull-up voltage VP is applied to the pull-up resistor R3, the forward voltage of the diode D1 from the pull-up voltage VP. A voltage Vo obtained by dividing the voltage obtained by subtracting Vf (“VP−Vf”) by the resistor R3 and the resistor R2 appears as the monitor voltage VM. On the other hand, when the winding 3 is short-circuited to the ground potential. Then, since the voltage Vs obtained by dividing the voltage “VP−Vf” by the resistor R3 and the parallel resistance of the resistor R2 and the resistor R1 appears as the monitor voltage VM, based on the monitor voltage VM. It is possible to determine whether the failure mode of the winding 3 is a disconnection failure or a ground short-circuit failure.

  Here, as an example, in the present embodiment, the resistance values of the resistors R1 and R3 are both set to 30 kΩ, and the resistance value of the resistor R2 is set to 10 kΩ. The forward voltage Vf of the diode D1 is assumed to be 0.6V. Under this condition, the voltage Vo is 1.1V and the voltage Vs is 0.88V. The voltage Vn varies depending on the battery voltage VB. For example, if VB = 14V, Vn = 3.5V, and if VB = 8V (assumed minimum value), Vn = 2V. Become. The resistance value ratio between the resistors R1 and R2 is such that the monitor voltage VM does not exceed the voltage range (maximum 5V) that can be read by the microcomputer 11 even if the battery voltage VB reaches the assumed maximum value (for example, 16V). Is set.

  In the SR motor drive device 20 according to the present embodiment, the microcomputer 11 detects the abnormality in FIG. 2 in order to distinguish and detect the disconnection failure and the ground short-circuit failure for each of the phase windings 3u, 3v, and 3w. Processing is to be executed.

In the following, the case where the abnormality detection process of FIG. 2 is executed for the U-phase winding 3u will be described as an example, but the same applies to the other-phase windings 3v and 3w.
As shown in FIG. 2, when the microcomputer 11 starts executing the abnormality detection process for the U-phase winding 3u, first, in S105, the power supply control transistor 9 is turned on to turn on the motor power relay 7. Then, the drive transistor 15 corresponding to the U phase, which is an abnormality detection target phase, is turned off. At this time, the microcomputer 11 does not output the pull-up voltage VPu to the pull-up resistor R3 corresponding to the U phase. That is, the pull-up resistor R3 is invalidated.

  Next, in S110, the U-phase monitor voltage VMu is A / D converted and read, and it is determined whether or not the monitor voltage VMu is equal to or higher than a predetermined normal determination value Vth1. The normality determination value Vth1 is set to the assumed minimum value (> 0V) when the voltage Vn is normal.

  Here, if the monitor voltage VMu is equal to or higher than the normal determination value Vth1 (S110: YES), it is determined that the winding 3u is normal and the abnormality detection process is terminated as it is, but the monitor voltage VMu is normal. If not Vth1 or more (S110: NO), it is determined that the winding 3u is abnormal, and the process proceeds to S120.

In S120, the pull-up voltage VPu is output to the pull-up resistor R3 corresponding to the U phase.
Next, in S130, the U-phase monitor voltage VMu is read again by A / D conversion, and it is determined whether or not the monitor voltage VMu is equal to or higher than a predetermined disconnection failure determination value Vth2H. Note that when the reading of the monitor voltage VMu is completed in S130, the output of the pull-up voltage VPu to the pull-up resistor R3 is stopped. Also, the disconnection failure determination value Vth2H is the same as the voltage Vo (= 1.1V) described above, or more than the voltage Vo in consideration of variations in the resistors R2, R3, the diode D1, and the pull-up voltage VPu. It is set to a slightly small value (that is, the minimum value for calculation of Vo) (see FIG. 3).

If it is determined that the monitor voltage VMu is equal to or higher than the disconnection failure determination value Vth2H (S130: YES), it is determined that the winding 3u is disconnected, and the process proceeds to S140.
In S140, it is prohibited to subsequently turn on the drive transistor 15 corresponding to the U phase, which is an abnormality detection phase.

  Then, in the next S150, it is determined whether or not an abnormality is detected for any of the other two-phase windings 3 (3v, 3w in this example), and the other two-phase windings 3 are abnormal. If there is no (normal), the process proceeds to S160, and the drive mode for operating the SR motor 1 is set to the two-phase drive mode. In this two-phase driving mode, only the driving transistor 15 corresponding to the normal two-phase winding 3 among the three-phase driving transistors 15 is turned on / off, and the energization control to the normal-phase winding 3 is performed. This is a drive mode in which the SR motor 1 is operated only by the above. When the setting in S160 is performed, the SR motor 1 is subsequently operated in the two-phase drive mode. In this case, since the output and control accuracy of the SR motor 1 are lower than normal, the operation of the SR motor 1 in the two-phase drive mode is a degenerate operation in which the operation is continued even if the performance is reduced when an abnormality occurs. It can be said that. Such a two-phase drive mode itself is a known technique.

  Next, in S170, a notification process for notifying the user (a driver of the vehicle in the present embodiment) that an abnormality has occurred in the SR motor 1 is performed. Then, the abnormality detection process ends.

  Note that the notification process performed in S170 may be, for example, a process of turning on a warning light in an instrument panel of a vehicle or displaying a message (such as a character or an icon) indicating the occurrence of an abnormality on a display device. In addition to the occurrence of an abnormality, for example, the type of abnormality (in this case, the winding 3 of the SR motor 1 is broken) and which phase of the winding 3 is operating are operated. A message for informing the user may be displayed on the display device. By such notification processing in S170, the driver can detect an abnormality even when the shift range of the automatic transmission is normally switched by the control (degenerate operation) of the SR motor 1 in the two-phase drive mode. You will notice that it has occurred. Therefore, it is possible to prompt the driver to perform a repair or the like, and it is possible to prevent the two-phase drive mode from continuing.

  On the other hand, if it is determined in S130 that the monitor voltage VMu is not equal to or higher than the disconnection failure determination value Vth2H, the process proceeds to S180, and it is determined whether or not the monitor voltage VMu is equal to or less than the short-circuit failure determination value Vth2L. To do. The short-circuit failure determination value Vth2L is smaller than the disconnection failure determination value Vth2H and is the same as the voltage Vs (= 0.88V) described above, or the resistors R1 to R3, the diode D1, and the pull-up In consideration of the variation of the voltage VPu, the voltage Vs is set to a value slightly larger than the voltage Vs (that is, the maximum value for calculating Vs) (see FIG. 3).

  If it is determined that the monitor voltage VMu is equal to or less than the short circuit failure determination value Vth2L (S180: YES), it is determined that the winding 3u is short-circuited to the ground potential, and the process proceeds to S190.

  In S190, the motor power supply relay 7 is turned off to cut off the supply of the battery voltage VB to the SR motor 1 and set the SR motor 1 in a prohibited state. This is because the SR motor 1 can no longer be operated when a ground short circuit failure of the winding 3 occurs in any one phase, and an excessive current that flows due to the winding 3 being short-circuited to the ground potential. This is to prevent the battery as a power source from being consumed.

  Then, in the subsequent S200, the function of the SR motor 1 (in this embodiment, the shift range switching function) does not work, and a ground short circuit failure has occurred in the winding 3 of the SR motor 1. Is notified to the driver. For example, a message (characters, icons, etc.) indicating them is displayed on a display device in the instrument panel of the vehicle. In addition to the type of abnormality, a message indicating which phase winding 3 is abnormal may be displayed on the display device. Then, the abnormality detection process ends. Note that the notification process of S200 can tell the driver the content of the failure (ground short circuit of the winding 3), and the failure location can be easily identified when repairing.

  Further, when it is determined in S150 that an abnormality is detected in any of the other two-phase windings 3, the process proceeds to S190 and the supply of the battery voltage VB to the SR motor 1 is cut off. Then, the SR motor 1 is set in a prohibited state. This is because even if the abnormality of the winding 3 is a disconnection failure, the SR motor 1 can no longer be operated if two or more phases are not normal.

  In addition, when it transfers to this S150 from S150, since the ground short circuit failure does not necessarily arise, in S200, for example, the function which the SR motor 1 bears to the driver (shift range switching function) A process for notifying only that there is a problem is performed. Still further, a process for notifying the failure contents of each abnormal phase winding 3 may be performed.

  On the other hand, if it is determined in S180 that the monitor voltage VMu is not equal to or less than the short-circuit failure determination value Vth2L, that is, if the monitor voltage VMu is greater than the short-circuit failure determination value Vth2L and smaller than the disconnection failure determination value Vth2H, It is determined that an indefinite abnormality that cannot be determined as a disconnection or a ground short-circuit has occurred in the winding 3u (see FIG. 3), and the process proceeds to S210. As the indefinite abnormality, a rare short (not a complete short) to the ground potential of the winding 3u can be considered.

In S210, a setting for performing temporary driving is performed, and then the abnormality detection process is terminated.
And the microcomputer 11 implements the following temporary drive, when the setting of said S210 is performed. That is, the operation of the SR motor 1 is attempted by controlling the drive transistor 15 of each phase. If it can be confirmed that the SR motor 1 operates normally on the basis of the signal from the rotary encoder described above, an indefinite abnormality of the U-phase winding 3u may cause a light rare short that can operate the SR motor 1. The normal control operation for driving the SR motor 1 in accordance with the operation of the shift lever is continued. In this case, the notification process similar to S170 described above may be performed. On the other hand, if the SR motor 1 does not operate normally, it is determined that the indefinite abnormality of the U-phase winding 3u is a severe rare short that does not allow the SR motor 1 to operate, and S190 and S200 in FIG. The same processing is performed.

  2 may be executed during a period in which the SR motor 1 is not operated. However, while the SR motor 1 is being operated, any of the phases may be detected. During the period when the drive transistor 15 is turned off, the processing after S110 except S105 may be executed as abnormality detection processing for the winding 3 of that phase.

Next, the operation of the abnormality detection process will be described with reference to FIG. Here, the U phase will be described as an example.
First, as shown in FIG. 4 (A) before the time t1 (left side) or before the time t2 in FIG. 4 (B) (left side), the motor power relay 7 is turned on and the drive transistor corresponds to the U phase. In the state where 15 is off and the pull-up voltage VPu is not applied to the U-phase corresponding pull-up resistor R3, the voltage VMu at the connection point of the U-phase corresponding resistors R1 and R2 is monitored (S110).

  If the U-phase winding 3u is normal, the monitor voltage VMu becomes the above-described voltage Vn, which is equal to or higher than the normal determination value Vth1, and therefore the U-phase winding 3u is determined normal in S110 (S110). : YES)

  In contrast, when the U-phase winding 3u is disconnected or shorted to the ground potential, as shown immediately after time t1 in FIG. 4A or immediately after time t2 in FIG. Since the monitor voltage VMu is 0 V and is smaller than the normal determination value Vth1, the U-phase winding 3u is determined to be abnormal in S110 (S110: NO), and the U-phase corresponding pull-up resistor R3 is determined in S120. A pull-up voltage VPu (= VC: 5 V) is applied to the capacitor.

  Here, when the U-phase winding 3u is disconnected, as shown after time t2 in FIG. 4B, when the pull-up voltage VPu is applied to the pull-up resistor R3, the monitor Since the voltage VMu is the voltage Vo described above and is equal to or higher than the disconnection failure determination value Vth2H, it is determined in S130 that the U-phase winding 3u is disconnected (S130: YES). In this case, the abnormal state of the other two phases is confirmed. If there is no abnormality (S150: NO), the SR motor 1 is operated only with the other normal two phases (S160).

  Also, when the U-phase winding 3u is short-circuited to the ground potential, as shown after time t1 in FIG. 4A, when the pull-up voltage VPu is applied to the pull-up resistor R3. Since the monitor voltage VMu is the above-described voltage Vs and is equal to or less than the short-circuit failure determination value Vth2L, it is determined in S180 that the U-phase winding 3u is short-circuited to the ground potential (S180: YES). In this case, the supply of the battery voltage VB to the SR motor 1 is cut off and the driving of the SR motor 1 is prohibited (S190).

  On the other hand, if the monitor voltage VMu is a voltage between the short-circuit failure determination value Vth2L and the disconnection failure determination value Vth2H, it is determined as an indefinite abnormality (S180: NO), and the SR motor 1 is temporarily driven (S210). If the SR motor 1 operates normally, the normal control operation is continued as it is.

  In the SR motor drive device 20 of the present embodiment as described above, by providing the pull-up resistor R3, the monitor voltage VM monitored by the microcomputer 11 depending on whether the winding 3 is disconnected or shorted to the ground potential. The voltages can be different. For this reason, the disconnection failure and the ground short-circuit failure of each phase winding 3 can be distinguished and detected with a simple configuration.

  In the SR motor drive device 20 of the present embodiment, the determination as to whether or not there is an abnormality in the winding 3 (S110) does not always apply the pull-up voltage VP to the pull-up resistor R3. This is performed without applying the pull-up voltage VP to the pull-up resistor R3, and it is determined that the winding 3 is abnormal (S110: NO), and it is determined whether the abnormality is a disconnection or a ground short circuit failure. Only when trying to do so, the pull-up voltage VP is applied to the pull-up resistor R3 (S120).

  Therefore, when the winding 3 is normal, the monitor voltage VM does not show an increase in voltage due to the pull-up resistor R3, and the monitor voltage VM that is not affected by the pull-up resistor R3 is fed back to the control of the SR motor 1. Can be used. For example, when the SR motor 1 is driven, if the monitor voltage VM when the drive transistor 15 is turned on is read, the voltage of the connection terminal 5 when the drive transistor 15 is turned on (and Voltage drop at the drive transistor 15) can be detected, and if the monitor voltage VM when the drive transistor 15 is turned off is read, the voltage at the connection terminal 5 when the drive transistor 15 is turned off from that value (As a result, the battery voltage VB) can be detected. Then, the adjustment control such as changing the on-time of the drive transistor 15 according to the detected values can be performed correctly.

  Further, in the SR motor drive device 20 of the present embodiment, when a disconnection failure of any one phase winding 3 is detected, the SR motor 1 is operated in a normal two-phase two-phase drive mode. Even when the SR motor 1 can operate, the probability that the SR motor 1 can operate can be increased, and the function using the SR motor 1 (in this example, the shift range switching function) can be prevented as much as possible. Further, when the SR motor 1 is controlled in the two-phase drive mode, the driver is notified of the occurrence of an abnormality, so that the driver can be prompted to perform repairs and the state of the two-phase drive mode is continued. Can be prevented.

  In addition, according to the SR motor driving device 20 of the present embodiment, a rare short to the ground potential can be detected as an indefinite abnormality as distinguished from the disconnection of the winding 3 and the ground short circuit. Further, when the indefinite abnormality is detected, if it can be confirmed that the SR motor 1 can be operated by the temporary drive described above, the normal control operation for the SR motor 1 is continued as it is, so that the operation continuation probability for the abnormality is increased. be able to.

  On the other hand, the microcomputer 11 reads the monitor voltage VM of each phase when the motor power relay 7 is turned off. If the monitor voltage VM is equal to or higher than the normal determination value Vth1, the winding 3 of the phase If the monitor voltage VM of all phases is equal to or higher than the normal determination value Vth1, the motor power relay 7 is in a failure state (on-fixed failure). It can also be configured such that it is determined.

In the present embodiment, the signal line from the connection terminal 5 to the A / D conversion input port of the microcomputer 11 via the resistor R1 corresponds to the voltage monitor signal line. Then, S110 to S130 and S180 in FIG. 2 correspond to the abnormality detection means. Further, S170 in FIG. 2 corresponds to the abnormality notifying unit, and S200 when proceeding from S180 in FIG. 2 corresponds to the short circuit failure notifying unit.
[Second Embodiment]
Next, FIG. 5 is a block diagram showing the configuration of the SR motor drive device 30 of the second embodiment. In FIG. 5, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG. Only the differences from the first embodiment will be described below.

As shown in FIG. 5, in the SR motor driving device 30 of the second embodiment, a pull-up voltage VP (= VC) of 5 V is constantly applied to one end of the pull-up resistor R3.
Therefore, if the driving transistor 15 is off and the motor power relay 7 is on and the winding 3 is normal, the monitor voltage VM is a voltage Vn obtained by dividing the battery voltage VB by the resistor R1 and the resistor R2 (FIG. 4 (see FIG. 6). This is because current flows through the pull-down resistor R2 not only from the connection terminal 5 side but also from the pull-up resistor R3 side.

  On the other hand, if the driving transistor 15 is off and the motor power supply relay 7 is on and the winding 3 is disconnected, the monitor voltage VM is pulled up as shown on the right side from time t4 in FIG. A voltage Vo obtained by subtracting the forward voltage Vf of the diode D1 from the voltage VP (“VP−Vf”) is a voltage Vo divided by the resistor R3 and the resistor R2, and the winding 3 is short-circuited to the ground potential. Then, as shown on the right side from time t3 in FIG. 6A, the monitor voltage VM divides the voltage “VP−Vf” by the resistor R3 and the parallel resistance of the resistor R2 and the resistor R1. The voltage is Vs.

  The magnitude relationship between the voltages Vn2, Vo, and Vs is “Vn2> Vo> Vs”. Therefore, based on the monitor voltage VM when the drive transistor 15 is off and the motor power supply relay 7 is on, it can be determined whether the winding 3 is normal, a disconnection failure, or a ground short-circuit failure.

  For this reason, in the SR motor drive device 30 of the second embodiment, the microcomputer 11 executes the process in which S120 is deleted from the abnormality detection process of FIG. 2 as the abnormality detection process. However, in S110, instead of the normal determination value Vth1, the monitor voltage VM is compared in magnitude with the normal determination value Vth3 set to the assumed minimum value when the voltage Vn2 is normal.

  That is, in the present embodiment, as shown in FIG. 7, for each phase winding 3u, 3v, 3w, if “VM ≧ Vth3”, it is normal, if “Vth3> VM ≧ Vth2H”, disconnection, “Vth2H> VM> Vth2L” ”Is determined as a rare short (undefined abnormality), and“ Vth2L ≧ VM ”is determined as a ground short.

  According to the SR motor drive device 30 of the second embodiment, except that the voltage increase due to the pull-up resistor R3 appears in the monitor voltage VM when the winding 3 is normal. The same effect as in the first embodiment can be obtained.

In the second embodiment as well, when the winding 3 is normal and normal, if the estimated value (calculated value) of the voltage increase due to the pull-up resistor R3 is subtracted from the detected value of the monitor voltage VM, the first value is obtained. Similar to the embodiment, the monitor voltage VM that is not affected by the pull-up resistor R3 can be obtained.
[Other Embodiments]
In each of the embodiments described above, the microcomputer 11 acquires the monitor voltage VM by performing A / D conversion. However, as shown in FIG. 8, the magnitude comparison between the monitor voltage VM and the determination value is performed outside the microcomputer 11. The comparators 23, 24, and 25 may be used.

  That is, the SR motor driving device 40 shown in FIG. 8 is a modification of the first embodiment. In the SR motor driving device 40, the comparator 23 that compares the monitor voltage VM with the normal determination value Vth1, and the monitor voltage A comparator 24 that compares the VM with the disconnection failure determination value Vth2H and a comparator 25 that compares the monitor voltage VM with the short-circuit failure determination value Vth2L are provided. In the abnormality detection process of FIG. 2, the microcomputer 11 determines whether or not “VM ≧ Vth1” based on the input signal from the comparator 23 in S110, and based on the input signal from the comparator 24 in S130. It is determined whether or not “VM ≧ Vth2H”. In S180, it is determined whether or not “VM ≦ Vth2L” based on the input signal from the comparator 24.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to such Embodiment at all, Of course, in the range which does not deviate from the summary of this invention, it can implement in a various aspect. .

  For example, in the SR motor drive device 20 of the first embodiment, when the microcomputer 11 determines that an indefinite abnormality has occurred in the winding 3 in S180 of the abnormality detection process, the pull-up voltage is applied to the pull-up resistor R3. VP is output in pulses, and the monitor voltage VM is continuously A / D converted and detected, and whether or not the winding 3 is rarely short-circuited by the time change of the monitor voltage VM, The degree of rare short may be determined. That is, the lighter the short-circuit to the ground potential of the winding 3, the more the connection terminal 5 becomes conductive to the ground potential with a large impedance, and the time constant increases, so the voltage VP is applied to the pull-up resistor R3. The rise of the monitor voltage VM at that time is delayed. For this reason, for example, the configuration may be such that the rare short is confirmed and the degree of the rare short is determined based on the delay time from when the voltage VP is applied to the pull-up resistor R3 until the monitor voltage VM becomes a predetermined value. .

  In each of the above embodiments, the pull-up resistor R3 is connected between the resistor R1 and the resistor R2. However, the pull-up resistor R3 may be connected between the connection terminal 5 and the resistor R1. In each of the above embodiments, the voltage at the connection terminal 5 is divided and monitored by the resistors R1 and R2. However, if the voltage at the connection terminal 5 is detected as a monitor voltage without being divided, the voltage is detected. The pull-down resistor R2 may be connected between the connection terminal 5 and the resistor R1.

  Further, the number of phases of the SR motor 1 may be three or more.

It is a block diagram showing the structure of SR motor drive device of 1st Embodiment. It is a flowchart showing the abnormality detection process of 1st Embodiment. It is explanatory drawing showing the setting state of the disconnection failure determination value Vth2H and the short circuit failure determination value Vth2L. It is explanatory drawing explaining the effect | action of 1st Embodiment. It is a block diagram showing the structure of the SR motor drive device of 2nd Embodiment. It is the 1st explanatory view explaining the operation of a 2nd embodiment. It is the 2nd explanatory view explaining operation of the 2nd embodiment. It is a block diagram showing the structure of the SR motor drive device of a modification. It is a block diagram showing the structure of the conventional SR motor drive device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... SR motor, 3 (3u, 3v, 3w) ... Winding, 5 (5u, 5v, 5w) ... Connection terminal, 7 ... Motor power relay, 9 ... Power supply control transistor, 11 ... Microcomputer, 15 ... Drive Transistor, 17 ... current detection resistor, 19 ... overcurrent detection circuit, 20, 30, 40 ... SR motor drive device, 23, 24, 25 ... comparator, D1 ... diode, R1 ... resistor, R2 ... pull-down resistor, R3 ... pull Up resistance

Claims (9)

For each phase winding of the SR motor to which a power supply voltage is supplied to one end, a connection terminal connected to the other end of the winding is provided in series between the connection terminal and the ground potential, and is turned on. In the SR motor driving device that includes a switching element that causes a current to flow through the winding, and operates the SR motor by controlling each switching element,
For each of the phase windings,
A voltage monitoring signal line connected to the connection terminal;
A pull-down resistor provided between a ground potential and the voltage monitoring signal line;
A pull-up resistor provided between a pull-up voltage higher than a ground potential and the voltage monitor signal line;
An anomaly detection means that operates when the switching element is off, and detects a disconnection failure of the winding and a short-circuit failure to the ground potential based on the voltage of the voltage monitoring signal line;
An SR motor driving device comprising: In the SR motor drive device according to claim 1,
The abnormality detecting means is adapted to switch between application of the pull-up voltage to the pull-up resistor and application stop of the pull-up voltage;
SR motor drive device characterized by this. In the SR motor drive device according to claim 2,
The abnormality detection means determines whether the winding is normal or abnormal based on the voltage of the voltage monitor signal line in a state where the application of the pull-up voltage to the pull-up resistor is stopped, If it is determined that there is an abnormality, the pull-up voltage is applied to the pull-up resistor, and based on the voltage of the voltage monitoring signal line, the winding abnormality is a disconnection failure and a short-circuit failure to the ground potential. To determine which one is
SR motor drive device characterized by this. In the SR motor drive device according to any one of claims 1 to 3,
When a disconnection failure of any one phase winding is detected by the abnormality detecting means, the SR motor is controlled by controlling only the switching elements corresponding to the normal phase windings among the switching elements. To perform a degenerate operation that activates
SR motor drive device characterized by this. In the SR motor driving device according to claim 4,
An abnormality notifying means for notifying a user of the SR motor that an abnormality has occurred when the degenerate operation is performed;
SR motor drive device characterized by this. In the SR motor driving device according to any one of claims 1 to 5,
When a short circuit failure to the ground potential of any one phase winding is detected by the abnormality detection means, the supply of the power supply voltage to each phase winding is cut off,
SR motor drive device characterized by this. In the SR motor drive device according to claim 6,
A short-circuit failure notification means for notifying a user of the SR motor that a short-circuit failure to the ground potential of the winding has occurred when the supply of the power supply voltage is interrupted;
SR motor drive device characterized by this. In the SR motor driving device according to any one of claims 1 to 7,
The abnormality detection means includes
A short-circuit fault determination value for determining that a short-circuit fault to the ground potential has occurred in the winding, and a value larger than the short-circuit fault determination value, and a disconnection fault has occurred in the winding A disconnection failure judgment value for judging
If the voltage of the voltage monitor signal line is a voltage between the short-circuit failure determination value and the disconnection failure determination value, it is determined that an indefinite abnormality has occurred in the winding;
SR motor drive device characterized by this. The SR motor drive device according to claim 8,
In the case where the indefinite abnormality of any one phase winding is detected by the abnormality detecting means, it is configured to check whether the SR motor operates by controlling the switching elements. ,
SR motor drive device characterized by this.

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