JP5494969B2 - Abnormality diagnosis device for rotation angle detection system - Google Patents

Description

  The present invention relates to an abnormality diagnosis device for a rotation angle detection system that determines the presence or absence of disconnection based on an output signal of a resolver that detects a rotation angle (rotation position) of a motor.

  Generally, a rotation angle detection system using a 1-input 2-output type (single-phase excitation 2-phase output type) resolver inputs an excitation signal (sinusoidal voltage signal) output from an excitation circuit to the resolver, and this excitation signal. The SIN signal modulated by sin θ and the COS signal modulated by cos θ according to the rotational position θ of the rotor are output from the resolver, and these two output signals (SIN signal and COS signal) are R / D converter (resolver digital converter) ) To detect the rotational position θ (rotation angle).

  As an abnormality diagnosis technique for a rotation angle detection system using such a resolver, for example, as described in Patent Document 1 (Japanese Patent No. 3071232), two output signals (SIN signal and COS signal) of the resolver are used. 1), a weak DC voltage for detecting disconnection is superimposed on the signal line, and the disconnection is detected by utilizing the fact that no DC voltage is detected when the signal line is disconnected.

Japanese Patent No. 3071232

  However, in the abnormality diagnosis technique disclosed in Patent Document 1, it is necessary to newly provide a circuit for superimposing a DC voltage for detecting disconnection on a signal line, and therefore, a request for cost reduction, which is an important technical problem in recent years. There is a drawback that it cannot be satisfied.

  In addition, in the rotation angle detection system using a resolver, the present applicant uses a sum of squares of two resolver output signals (SIN signal and COS signal) as a diagnostic index, and compares the diagnostic index with a predetermined abnormality determination threshold value. Then, we are studying abnormality diagnosis technology for determining the presence or absence of disconnection (for example, disconnection of resolver input signal line or output signal line), but the following new problems were found in the research process.

  As shown in FIG. 8, if it is an ideal system having no circuit error (resistance or capacitor variation, sampling timing deviation, etc.), the normal diagnostic index (the sum of squares of the two output signals of the resolver) However, in an actual system, since a circuit error exists, the diagnosis index fluctuates (vibrates) depending on the rotor rotational position even under normal conditions due to the influence of the circuit error. In this way, if the abnormality determination threshold is set taking into consideration that the normal diagnostic index fluctuates due to the influence of the circuit error, it is possible to avoid erroneously determining that there is an abnormality (disconnected) even though it is normal. it can. However, because the diagnostic index at the time of abnormality (disconnection) also fluctuates (vibrates) greatly depending on the rotor rotation position, the rotor rotation at which the diagnostic index at the time of abnormality is on the same side as the diagnostic index at normal time with respect to the abnormality determination threshold There is a position area, and this area is an “abnormality detection impossible area” in which an abnormality (disconnection) cannot be detected.

  For this reason, in order to detect disconnection at an early stage, if the abnormality diagnosis for determining the presence or absence of disconnection is executed while the rotation of the motor immediately after the motor control system is started, the rotor rotation stop position of the resolver is detected as abnormal. In the case of the impossible area, there is a problem that even if a disconnection occurs, the disconnection cannot be detected.

  Therefore, the problem to be solved by the present invention is to provide an abnormality diagnosis device for a rotation angle detection system that can detect the disconnection at an early stage when the disconnection occurs while satisfying the demand for cost reduction. It is in.

  In order to solve the above-mentioned problem, the invention according to claim 1 is directed to a state in which a motor as a power source of a vehicle can freely rotate (for example, power transmission even if the motor is disconnected from the power transmission system and the motor rotates). Rotation angle detection system provided with an abnormality diagnosis means that is applied to a vehicle having a state that does not affect the system) and that performs abnormality diagnosis that determines the presence or absence of disconnection based on the output signal of a resolver that detects the rotation angle of a motor In the abnormality diagnosis apparatus, the abnormality diagnosis means is configured to execute abnormality diagnosis by rotating the motor by other control without using the output signal of the resolver in a state where the motor can freely rotate immediately after starting the motor control system. It is a thing.

  In this configuration, immediately after the start of the motor control system, the motor is rotated by other control and an abnormality diagnosis is performed to determine the presence or absence of disconnection based on the output signal of the resolver. Even if the rotor rotation stop position is in an area where abnormality cannot be detected, if a disconnection occurs, it will enter the area where the resolver's rotor rotation position can be detected abnormally (area other than the area where abnormality cannot be detected) as the motor rotates. The disconnection can be detected. Thereby, when a disconnection occurs, the disconnection can be detected immediately after the start of the motor control system. In addition, it is not necessary to newly provide a circuit for superimposing a DC voltage for detecting disconnection on a signal line as in the prior art, and it is possible to satisfy the demand for cost reduction, which is an important technical problem in recent years. .

  In this case, as in claim 2, when the motor is rotated by other control, the motor may be controlled so that the rotor of the resolver is rotated 180 degrees or more. Alternatively, as described in claim 3, when the motor is rotated by other control, the motor may be controlled to rotate until a predetermined rotational speed is reached. In this way, it is possible to ensure that the rotor rotational position of the resolver enters an area where abnormality can be detected as the motor rotates.

FIG. 1 is a diagram showing a schematic configuration of a drive system for a hybrid vehicle in Embodiment 1 of the present invention. FIG. 2 is a diagram showing a schematic configuration of the rotation angle detection system. FIG. 3 is a diagram for explaining the behavior of the excitation signal, the SIN signal, and the COS signal. FIG. 4 is a diagram for explaining a diagnosis index for abnormality diagnosis and a region in which abnormality cannot be detected according to the first embodiment. FIG. 5 is a flowchart for explaining the processing flow of the motor control routine of the first embodiment. FIG. 6 is a flowchart for explaining the flow of processing of the abnormality diagnosis routine (first abnormality diagnosis routine) of the first embodiment. FIG. 7 is a flowchart for explaining the processing flow of the disconnection determination routine of the first embodiment. FIG. 8 is a diagram for explaining an abnormality diagnosis diagnosis index and an abnormality non-detectable region of Example 2 as a reference example related to the present invention . FIG. 9 is a flowchart for explaining the flow of processing of the motor stop control routine of the second embodiment. FIG. 10 is a flowchart for explaining the flow of processing of the motor control routine of the second embodiment. FIG. 11 is a flowchart for explaining the processing flow of the abnormality diagnosis routine (second abnormality diagnosis routine) according to the second embodiment.

  Hereinafter, several embodiments in which the mode for carrying out the invention is applied to a hybrid vehicle will be described.

A first embodiment of the present invention will be described with reference to FIGS.
First, a schematic configuration of a hybrid vehicle drive system will be described with reference to FIG.
An engine 11 that is an internal combustion engine and an AC motor 12 are mounted as power sources for the vehicle. The power of the output shaft (crankshaft) of the engine 11 is transmitted to the transmission 13 via the AC motor 12, and the power of the output shaft of the transmission 13 is transmitted to the wheels 16 via the differential gear mechanism 14, the axle 15 and the like. Is done. The transmission 13 may be, for example, a torque converter and a transmission mechanism, and may be a stepped transmission that switches a gear step from a plurality of gear steps in a stepwise manner, or a CVT (steplessly variable) that changes continuously. Transmission).

  A first clutch 17 for interrupting power transmission is provided between the engine 11 and the AC motor 12 in the power transmission path for transmitting the power of the engine 11 to the wheels 16. And the transmission 13 is provided with a second clutch 18 for intermittently transmitting power. The first and second clutches 17 and 18 may be hydraulically driven hydraulic clutches or electromagnetically driven electromagnetic clutches. Both the first and second clutches 17 and 18 are in a disengaged state (a state in which power is not transmitted), so that the AC motor 12 can freely rotate (the AC motor 12 is disconnected from the power transmission system, and the AC motor 12 The state where the power transmission system is not affected even if the motor rotates.

  An inverter 19 that drives the AC motor 12 is connected to the battery 20, and the AC motor 12 exchanges power with the battery 20 via the inverter 19. An electronic control circuit for motor control (hereinafter referred to as “MG-ECU”) 21 controls the operation of AC motor 12 by controlling inverter 19 in accordance with the driving state of the vehicle.

Next, a schematic configuration of the rotation angle detection system will be described based on FIG.
A resolver 22 for detecting the rotation angle (rotation position) of the AC motor 12 is mounted on the AC motor 12 (see FIG. 1) used as a power source of the vehicle. This resolver 22 is a 1-input 2-output type (one-phase excitation two-phase output type) and is connected to the MG-ECU 21. The MG-ECU 21 inputs the excitation signal (sinusoidal voltage signal) output from the excitation circuit 23 to the resolver 22, and the resolver 22 uses the SIN signal obtained by modulating the excitation signal with sin θ according to the rotational position θ of the rotor and cos θ. A modulated COS signal is output. The MG-ECU 21 amplifies two output signals (SIN signal and COS signal) of the resolver 22 by the differential amplifier circuits 24 and 25, respectively, and inputs them to the R / D converter 26 (resolver digital converter). The D converter 26 converts the two output signals (amplified SIN signal and COS signal) of the resolver 22 into a rotational position θ (digital signal) and inputs the rotational position θ (digital signal) to the microcomputer 27 (microcomputer). θ (rotation angle) is detected.

  Further, the MG-ECU 21 uses the microcomputer 27 to output two output signals (amplified SIN signal and COS signal) of the resolver 22 via the A / D converter 28 in order to perform abnormality diagnosis of the rotation angle detection system. And an excitation signal (REF signal) that is an input signal of the resolver 22 is input to the microcomputer 27 via the A / D converter 28. It should be noted that the excitation signal (REF signal) may not be input to the microcomputer 27.

  As shown in FIG. 3, during normal operation, the excitation signal (REF signal), the SIN signal, and the COS signal input to the microcomputer 27 of the MG-ECU 21 oscillate around a reference voltage (for example, 2.5 V).

  On the other hand, when an abnormality occurs (when a break occurs in any of the excitation signal line L1, the SIN signal line L2, and the COS signal line L3), the SIN signal and the COS signal input to the microcomputer 27 of the MG-ECU 21 are It shows the following behavior.

(1) When the excitation signal line L1 is disconnected, both the SIN signal and the COS signal input to the microcomputer 27 become constant values (for example, 2.5 V).
(2) When both the SIN signal line L2 and the COS signal line L3 are disconnected, both the SIN signal and the COS signal input to the microcomputer 27 have a constant value (for example, 2.5 V).
(3) When only the SIN signal line L2 is disconnected, only the SIN signal input to the microcomputer 27 becomes a constant value (for example, 2.5 V).
(4) When only the COS signal line L3 is disconnected, only the COS signal input to the microcomputer 27 becomes a constant value (for example, 2.5 V).

  Focusing on such characteristics, in the first embodiment, as shown in FIG. 4, the difference between the SIN signal input to the microcomputer 27 and a reference voltage (for example, 2.5 V) is expressed as a diagnostic index ( = SIN signal-reference voltage), and the difference between the COS signal input to the microcomputer 27 and the reference voltage (for example, 2.5 V) is used as a diagnostic index (= COS signal-reference voltage) on the COS signal side. An abnormality diagnosis for determining the presence or absence of disconnection based on the diagnostic index on the SIN signal side and the diagnostic index on the COS signal side is performed as follows.

  (A) The absolute value of the diagnostic index on the SIN signal side (= | SIN signal−reference voltage |) is smaller than the first threshold (for example, 0.2 V), and the absolute value of the diagnostic index on the COS signal side (= When | COS signal−reference voltage |) is smaller than the first threshold value (for example, 0.2 V), since the diagnostic index on the SIN signal side and the diagnostic index on the COS signal side are both near 0, the SIN signal And COS signals are both determined to be constant values, and it is determined that there is an abnormality (the excitation signal line L1 is disconnected, or both the SIN signal line L2 and the COS signal line L3 are disconnected).

  (B) The absolute value of the diagnostic indicator on the SIN signal side (= | SIN signal−reference voltage |) is smaller than the first threshold (for example, 0.2 V), and the absolute value of the diagnostic indicator on the COS signal side (= When | COS signal−reference voltage |) is smaller than the second threshold value (for example, 1.4 V), only the diagnostic index on the SIN signal side is near 0, so that only the SIN signal is determined to be a constant value. Then, it is determined that there is an abnormality (the SIN signal line L2 is disconnected).

  In this case, as shown in FIG. 4A, in the rotor rotation stop position region A1 where the absolute value of the diagnostic index on the COS signal side is equal to or greater than a second threshold value (eg, 1.4 V), the SIN signal is normal. Since the absolute value of the diagnostic index on the side may be smaller than the first threshold (for example, 0.2 V), this region is excluded as an abnormality detection unusable region A1 on the SIN signal side.

  (C) The absolute value of the diagnostic index on the COS signal side (= | COS signal−reference voltage |) is smaller than the first threshold (for example, 0.2 V), and the absolute value of the diagnostic index on the SIN signal side (= When | SIN signal−reference voltage |) is smaller than the second threshold value (for example, 1.4 V), only the diagnostic index on the COS signal side is close to 0, so that only the COS signal is determined to be a constant value. Then, it is determined that there is an abnormality (the COS signal line L3 is disconnected).

  In this case, as shown in FIG. 4B, in the region A2 of the rotor rotation stop position where the absolute value of the diagnostic indicator on the SIN signal side is equal to or greater than a second threshold (for example, 1.4 V), the COS signal is normal even. Since the absolute value of the diagnostic index on the side may be smaller than the first threshold (for example, 0.2 V), this region is excluded as an abnormal detection unusable region A2 on the COS signal side.

  By the way, in order to detect the disconnection at an early stage, the abnormality diagnosis (diagnosis index on the SIN signal side and the COS signal side) described above is performed while the rotation of the AC motor 12 is stopped immediately after the motor control system is started (for example, immediately after the ignition switch is turned on). If an abnormality diagnosis for determining the presence or absence of disconnection based on the diagnostic index is performed, if the rotor rotation stop position of the resolver 22 is in an area where an abnormality cannot be detected, even if a disconnection occurs, the disconnection occurs. May not be detected. For example, when the rotor rotation stop position of the resolver 22 is in the abnormality detection impossible area A1 on the SIN signal side, the disconnection of the SIN signal line L2 cannot be detected. Further, when the rotor rotation stop position of the resolver 22 is in the abnormality detection unusable area A2 on the COS signal side, the disconnection of the COS signal line L3 cannot be detected.

  As a countermeasure, in the first embodiment, immediately after the motor control system is started (for example, immediately after the ignition switch is turned on), the AC motor is controlled by other control without using the output signal of the resolver 22 while the AC motor 12 can freely rotate. 12 is rotated by a predetermined angle (for example, 180 degrees) or more, and abnormality diagnosis is performed to determine the presence or absence of disconnection based on the diagnostic index on the SIN signal side and the diagnostic index on the COS signal side. Thus, even if the rotor rotation stop position of the resolver 22 before the rotation of the AC motor 12 is in the abnormality detection impossible area A1 on the SIN signal side, if the disconnection of the SIN signal line L2 occurs, the rotation of the AC motor 12 Accordingly, when the rotor rotational position of the resolver 22 enters the region where the abnormality can be detected on the SIN signal side (region other than the region A1 where the abnormality cannot be detected), the disconnection of the SIN signal line L2 can be detected. Further, even when the rotor rotation stop position of the resolver 22 before the rotation of the AC motor 12 is in the COS signal side abnormality detection impossible region A2, if the disconnection of the COS signal line L3 occurs, the AC motor 12 is rotated. Along with this, when the rotor rotational position of the resolver 22 enters the region where the abnormality can be detected on the COS signal side (region other than the region A2 where abnormality cannot be detected), the disconnection of the COS signal line L3 can be detected.

  The abnormality diagnosis according to the first embodiment described above is executed by the MG-ECU 21 according to the routines shown in FIGS. Hereinafter, the processing content of each of these routines will be described.

[Motor control routine]
The motor control routine shown in FIG. 5 is repeatedly executed at a predetermined cycle after the MG-ECU 21 is turned on (after the ignition switch is turned on). When this routine is started, first, at step 101, it is determined whether or not it is immediately after the start of the inverter 19 (at the time of the first start of this routine after the start of the inverter 19). If it is determined, the process proceeds to step 102 where initial setting (for example, setting of an initial value) is performed.

  Thereafter, the process proceeds to step 103, and a first abnormality diagnosis routine of FIG. 6 to be described later is executed, so that immediately after the motor control system is started, the AC motor 12 is controlled by other control in a state where the AC motor 12 can freely rotate. , And an abnormality diagnosis is performed to determine the presence or absence of disconnection based on the diagnostic indicator on the SIN signal side and the diagnostic indicator on the COS signal side during the rotation. Thereafter, the routine proceeds to step 104 where normal control for controlling the operation of the AC motor 12 by controlling the inverter 19 in accordance with the driving state of the vehicle and the like is executed.

[First abnormality diagnosis routine]
The first abnormality diagnosis routine shown in FIG. 6 is a subroutine executed in step 103 of the motor control routine of FIG. 5 and serves as abnormality diagnosis means in the claims. When this routine is started, first, at step 201, it is determined whether or not the rotor of the resolver 22 has rotated by a predetermined angle or more. Here, the predetermined angle is set to an angle of 180 degrees or more (for example, 180 degrees, 270 degrees, 360 degrees, etc.).

  If it is determined in this step 201 that the rotor of the resolver 22 has not yet rotated more than a predetermined angle, the process proceeds to step 202 where the output signal of the resolver 22 is not used while the AC motor 12 is freely rotatable. The AC motor 12 is rotated by the control. At this time, the AC motor 12 is controlled so as to rotate the rotor of the resolver 22 by a predetermined angle or more (for example, the AC motor 12 so that the rotor of the resolver 22 stops at a position rotated by a predetermined angle or slightly larger angle). Control the current).

  In this way, by controlling the AC motor 12 so that the rotor of the resolver 22 is rotated by a predetermined angle (for example, 180 degrees) or more, the rotor rotation position of the resolver 22 can be reliably detected in the SIN signal side abnormality detection region (abnormality). An area other than the undetectable area A1) and an area in which an abnormality can be detected on the COS signal side (an area other than the undetectable area A2) can be entered.

  Thereafter, the process proceeds to step 203, where the difference between the SIN signal input to the microcomputer 27 and a reference voltage (for example, 2.5V) is calculated as a diagnostic indicator (= SIN signal−reference voltage) on the SIN signal side, and the microcomputer 27 The difference between the COS signal input to the reference voltage and a reference voltage (for example, 2.5 V) is calculated as a diagnostic index (= COS signal−reference voltage) on the COS signal side.

Thereafter, the process proceeds to step 204, and a disconnection determination routine of FIG. 7 described later is executed to determine the presence or absence of disconnection based on the diagnostic index on the SIN signal side and the diagnostic index on the COS signal side. Thereafter, the process proceeds to step 205, and it is determined whether or not an abnormality (disconnection) has been established based on the determination result of the disconnection determination process (step 204).
If it is determined in step 205 that an abnormality (disconnection) has not been established, the process proceeds to step 206, and this routine is terminated while the abnormality flag is kept off.

  On the other hand, if it is determined in step 205 that an abnormality (disconnection) has been established, the process proceeds to step 207, the abnormality flag is set to ON, and a warning lamp (not shown) provided on the instrument panel of the driver's seat is displayed. Light up or flash, or display a warning on the warning display (not shown) on the instrument panel of the driver's seat to warn the driver and back up the abnormal information (abnormal code, etc.) The program is stored in a rewritable non-volatile memory such as a RAM (not shown), and this routine is terminated.

[Disconnection judgment routine]
The disconnection determination routine shown in FIG. 7 is a subroutine executed in step 204 of the first abnormality diagnosis routine of FIG. When this routine is started, first, in step 301, the absolute value (= | SIN signal−reference voltage |) of the diagnostic index on the SIN signal side is smaller than a first threshold (for example, 0.2V), and It is determined whether or not the absolute value (= | COS signal−reference voltage |) of the diagnostic index on the COS signal side is smaller than a first threshold (for example, 0.2 V).

  If “Yes” is determined in step 301 (that is, the absolute value of the diagnostic index on the SIN signal side is smaller than the first threshold value, and the absolute value of the diagnostic index on the COS signal side is smaller than the first threshold value). If it is determined that the diagnostic index on the SIN signal side and the diagnostic index on the COS signal side are both near 0, it is determined that both the SIN signal and the COS signal are constant values. Proceeding to 304, it is determined that there is an abnormality (the excitation signal line L1 is disconnected, or both the SIN signal line L2 and the COS signal line L3 are disconnected). It should be noted that it may be determined that there is an abnormality when the number of consecutive times or the number of integration times determined as “Yes” in step 301 exceeds a predetermined value.

  On the other hand, if “No” is determined in step 301, the process proceeds to step 302, where the absolute value (= | SIN signal−reference voltage |) of the diagnostic index on the SIN signal side is the first threshold (for example, 0. It is determined whether or not the absolute value (= | COS signal−reference voltage |) of the diagnostic index on the COS signal side is smaller than a second threshold value (for example, 1.4 V).

  When it is determined as “Yes” in step 302 (that is, the absolute value of the diagnostic index on the SIN signal side is smaller than the first threshold value, and the absolute value of the diagnostic index on the COS signal side is smaller than the second threshold value). If it is determined that it is small), since only the diagnostic index on the SIN signal side is near 0, it is determined that only the SIN signal is a constant value, and the process proceeds to Step 305, where there is an abnormality (in the SIN signal line L2). It is determined that there is a break. It should be noted that it may be determined that there is an abnormality when the number of consecutive times or the number of integrations determined as “Yes” in step 302 exceeds a predetermined value.

  On the other hand, if “No” is determined in step 302, the process proceeds to step 303, where the absolute value (= | COS signal−reference voltage |) of the diagnostic index on the COS signal side is the first threshold value (for example, 0. It is determined whether or not the absolute value (= | SIN signal−reference voltage |) of the diagnostic index on the SIN signal side is smaller than a second threshold (for example, 1.4 V).

If “Yes” is determined in step 303 (that is, the absolute value of the diagnostic index on the COS signal side is smaller than the first threshold value, and the absolute value of the diagnostic index on the SIN signal side is smaller than the second threshold value). If it is determined that the COS signal is small, only the COS signal-side diagnostic index is near 0, so it is determined that only the COS signal is a constant value, and the process proceeds to step 306, where there is an abnormality (the COS signal line L3). It is determined that there is a break. It should be noted that it may be determined that there is an abnormality when the number of consecutive times or the number of integrations determined as “Yes” in step 303 exceeds a predetermined value.
If all the determinations in Steps 301 to 303 are “No”, the process proceeds to Step 307 to determine that there is no abnormality (no disconnection).

  In the first embodiment described above, immediately after the start of the motor control system, the AC motor 12 is rotated by other control, and the presence or absence of disconnection is determined based on the diagnostic index on the SIN signal side and the diagnostic index on the COS signal side. Therefore, even if the rotor rotation stop position of the resolver 22 before the rotation of the AC motor 12 is in a region where an abnormality cannot be detected, if a disconnection occurs, the AC motor 12 is rotated. When the rotor rotational position of the resolver 22 enters an area where abnormality can be detected, the disconnection can be detected. Thereby, when a disconnection occurs, the disconnection can be detected immediately after the start of the motor control system. In addition, it is not necessary to newly provide a circuit for superimposing a DC voltage for detecting disconnection on a signal line as in the prior art, and it is possible to satisfy the demand for cost reduction, which is an important technical problem in recent years. .

  In the first embodiment, when the AC motor 12 is rotated by other control, the AC motor 12 is controlled so that the rotor of the resolver 22 is rotated by a predetermined angle (for example, 180 degrees) or more. For example, when the AC motor 12 is rotated by other control, the AC motor 12 may be controlled to rotate until a predetermined rotation speed (for example, several tens of rpm) is reached. Even in this case, the rotor rotational position of the resolver 22 can surely enter an area where abnormality can be detected as the AC motor 12 rotates.

  The method for determining the presence or absence of disconnection based on the diagnostic indicator on the SIN signal side and the diagnostic indicator on the COS signal side is not limited to the method described in the first embodiment, and may be changed as appropriate.

Next, a second embodiment as a reference example related to the present invention will be described with reference to FIGS. However, description of substantially the same parts as those in the first embodiment will be omitted or simplified, and different parts from the first embodiment will be mainly described.

  In the second embodiment, the sum of squares of two output signals of the resolver 22 (SIN signal and COS signal input to the microcomputer 27) is used as a diagnostic index, and the diagnostic index is compared with a predetermined abnormality determination threshold value. Execute an abnormality diagnosis to determine the presence or absence.

  As shown in FIG. 8, in an ideal system having no circuit error (resistance or capacitor variation, sampling timing deviation, etc.), the normal diagnostic index (the square sum of the two output signals of the resolver 22) ) Should be a constant value, but in an actual system, since a circuit error exists, the diagnosis index fluctuates (vibrates) depending on the rotor rotational position even under normal conditions due to the influence of the circuit error. In this way, if the abnormality determination threshold is set taking into consideration that the normal diagnostic index fluctuates due to the influence of the circuit error, it is possible to avoid erroneously determining that there is an abnormality (disconnected) even though it is normal. it can. However, because the diagnostic index at the time of abnormality (disconnection) also fluctuates (vibrates) greatly depending on the rotor rotation position, the rotor rotation at which the diagnostic index at the time of abnormality is on the same side as the diagnostic index at normal time with respect to the abnormality determination threshold There is a position area, and this area is an “abnormality detection impossible area” in which an abnormality (disconnection) cannot be detected.

  For this reason, in order to detect the disconnection early, the abnormality diagnosis described above (2 of the two output signals of the resolver 22) is performed while the rotation of the AC motor 12 is stopped immediately after the start of the motor control system (for example, immediately after the ignition switch is turned on). If the sum of the multiplication is compared with an abnormality determination threshold value and an abnormality diagnosis for determining the presence or absence of disconnection is executed, if the rotor rotation stop position of the resolver 22 is in the region where the abnormality cannot be detected, a disconnection has occurred. However, the disconnection cannot be detected.

  As a countermeasure against this, in the second embodiment, when the rotation of the AC motor 12 is stopped, the rotational position of the resolver 22 suitable for abnormality diagnosis in a state in which the AC motor 12 can freely rotate (area where abnormality can be detected). By controlling the rotation stop position of the AC motor 12 so as to stop at the position, the rotor rotation stop position of the resolver 22 is controlled to an area where an abnormality can be detected (an area other than the area where an abnormality cannot be detected). Thereby, when the motor control system is stopped after the rotation of the AC motor 12 is stopped, the rotor rotation stop position of the resolver 22 can be set in a region where abnormality can be detected. Then, the abnormality diagnosis is executed in a state where the rotor rotation stop position of the resolver 22 is in a region where the abnormality can be detected by executing the abnormality diagnosis while the rotation of the AC motor 12 is stopped immediately after starting the next motor control system. If a disconnection occurs, the disconnection can be detected.

  The abnormality diagnosis according to the second embodiment described above is executed by the MG-ECU 21 according to the routines shown in FIGS. Hereinafter, the processing content of each of these routines will be described.

[Motor stop control routine]
Motor stop control routine shown in FIG. 9, Ru is repeatedly executed at a predetermined cycle during the power-on MG-ECU 21. When this routine is started, first, at step 401, it is determined whether or not a motor stop command has been generated. When it is determined that a motor stop command has been generated, the routine proceeds to step 402 where the motor rotation speed command value is determined. Based on (for example, 0 rpm) or a motor torque command value (for example, 0 Nm), the inverter 19 is controlled to execute normal stop control for stopping the rotation of the AC motor 12.

  Thereafter, the process proceeds to step 403, where it is determined whether or not the motor rotational speed (the rotational speed of the AC motor 12) has decreased below a predetermined value (for example, 10 rpm), and it is determined that the motor rotational speed is equal to or higher than the predetermined value. If so, the process returns to step 402 and the normal stop control is continued.

  Thereafter, when it is determined in step 403 that the motor rotation speed has decreased below a predetermined value, the process proceeds to step 404 where the rotor of the resolver 22 rotates in a state suitable for abnormality diagnosis while the AC motor 12 can freely rotate. Stop position control for controlling the rotation stop position of AC motor 12 so as to stop at the position (area where abnormality can be detected) is executed. In this case, for example, the current of the AC motor 12 is controlled so that the rotor of the resolver 22 rotates to a rotational position within a region where abnormality can be detected and stops.

[Motor control routine]
The motor control routine shown in FIG. 10 is repeatedly executed at a predetermined cycle after the MG-ECU 21 is turned on (after the ignition switch is turned on). When this routine is started, first, in step 501, it is determined whether or not it is immediately after starting the inverter 19 (at the time of starting the first main routine after starting the inverter 19). If it is determined, the process proceeds to step 502 and initial setting (for example, setting of an initial value) is performed.

  Thereafter, the process proceeds to step 503, and a second abnormality diagnosis routine shown in FIG. 11 to be described later is executed, so that the two output signals (microcomputers) of the resolver 22 are stopped while the rotation of the AC motor 12 is stopped immediately after the start of the motor control system. The sum of squares of the SIN signal and the COS signal input to 27 is calculated as a diagnostic index, and the diagnostic index is compared with a predetermined abnormality determination threshold value to perform abnormality diagnosis for determining the presence or absence of disconnection. Thereafter, the process proceeds to step 504, where normal control for controlling the operation of the AC motor 12 by controlling the inverter 19 according to the driving state of the vehicle and the like is executed.

[Second abnormality diagnosis routine]
Second abnormality diagnosis routine shown in FIG. 11, Ru subroutine der executed in step 503 of the motor control routine of FIG. 10. When this routine is started, first, in step 601, it is determined whether or not the rotation of the AC motor 12 is stopped. If it is determined that the rotation of the AC motor 12 is stopped, the process proceeds to step 602. The sum of squares of two output signals of the resolver 22 (SIN signal and COS signal input to the microcomputer 27) is calculated as a diagnostic index.

  Thereafter, the process proceeds to step 603, where it is determined whether the diagnostic index is smaller than a predetermined abnormality determination threshold value. Here, the abnormality determination threshold is set taking into consideration that the diagnostic index during normal operation varies due to the influence of a circuit error.

  If it is determined in step 603 that the diagnostic index is equal to or greater than the abnormality determination threshold value, the process proceeds to step 604, where it is determined that there is no abnormality (no disconnection), and this routine is performed while the abnormality flag is kept off. finish.

  On the other hand, if it is determined in step 603 that the diagnostic index is smaller than the abnormality determination threshold value, the process proceeds to step 605, where there is an abnormality (excitation signal line L1, SIN signal line L2, and COS signal line L3). Either one of them is broken), the abnormality flag is set to ON, and a warning lamp (not shown) provided on the instrument panel of the driver's seat lights or blinks, or the driver's seat A warning display unit (not shown) of the instrument panel is used to warn the driver, and the abnormality information (abnormal code, etc.) is stored in a rewritable nonvolatile memory such as a backup RAM (not shown). Then, this routine is finished. It should be noted that it may be determined that there is an abnormality when the number of consecutive times or the number of integration times determined as “Yes” in step 603 exceeds a predetermined value.

  In the second embodiment described above, when the rotation of the AC motor 12 is stopped, the rotation of the AC motor 12 is stopped so that the rotor of the resolver 22 stops at a rotation position suitable for abnormality diagnosis (an area where abnormality can be detected). Since the position is controlled, the rotor rotation stop position of the resolver 22 can be controlled to a region where abnormality can be detected (a region other than a region where abnormality cannot be detected). Thereby, when the motor control system is stopped after the rotation of the AC motor 12 is stopped, the rotor rotation stop position of the resolver 22 can be set in a region where abnormality can be detected. Then, while the rotation of the AC motor 12 is stopped immediately after the start of the next motor control system, the abnormality diagnosis for determining the presence or absence of disconnection is executed using the square sum of the two output signals of the resolver 22 as a diagnostic index. The abnormality diagnosis can be executed in a state where the rotor rotation stop position of the resolver 22 is in a region where the abnormality can be detected. If a disconnection occurs, the disconnection can be detected. Even if it does in this way, when disconnection generate | occur | produces, while being able to detect the disconnection immediately after starting of a motor control system, the request | requirement of the cost reduction which is an important technical subject in recent years is satisfied. it can.

Note that the method of determining the presence or absence of disconnection using the square sum of the two output signals of the resolver 22 as a diagnostic index is not limited to the method described in the second embodiment, and may be changed as appropriate.
Further, immediately after the start of the motor control system, the AC motor 12 is rotated by other control, and an abnormality diagnosis is performed to determine the presence or absence of disconnection using the sum of squares of the two output signals of the resolver 22 as a diagnostic index. May be.

  In the first embodiment, the present invention is applied to a system that executes an abnormality diagnosis for determining the presence or absence of disconnection based on the diagnostic index on the SIN signal side and the diagnostic index on the COS signal side. In the second embodiment, the resolver Although the present invention is applied to a system that executes an abnormality diagnosis for determining the presence or absence of disconnection using the sum of squares of two output signals of 22 as a diagnostic index, the present invention is not limited to this, and the present invention is not limited to this. The present invention can be widely applied to various systems that execute abnormality diagnosis that determines the presence or absence of disconnection based on a signal.

  In the first and second embodiments, the present invention is applied to the rotation angle detection system for a motor mounted on a hybrid vehicle using both the engine and the motor as power sources. However, the present invention is not limited to this, and only the motor is used. You may apply this invention to the rotation angle detection system of the motor mounted in the electric vehicle used as a motive power source.

11 ... engine (internal combustion engine), 12 ... AC motor, 13 ... transmission, 17: clutch, 19 ... inverter, 20 ... battery, 21 ... MG-ECU (abnormality diagnosis hand stage), 22 ... resolver, 23 ... Excitation circuit, 24, 25 ... differential amplification circuit, 26 ... R / D converter, 27 ... microcomputer

Claims (3)

An abnormality diagnosing unit that is applied to a vehicle in which a motor serving as a power source of the vehicle exists in a state in which the motor can freely rotate, and performs an abnormality diagnosis for determining the presence or absence of disconnection based on an output signal of a resolver that detects a rotation angle of the motor. In the abnormality diagnosis device of the rotation angle detection system provided,
The abnormality diagnosis means executes the abnormality diagnosis by rotating the motor by other control without using the output signal of the resolver in a state where the motor can freely rotate immediately after starting the motor control system. An abnormality diagnosis device for a rotation angle detection system.   2. The rotation angle detection according to claim 1, wherein the abnormality diagnosis unit controls the motor so as to rotate a rotor of the resolver by 180 degrees or more when the motor is rotated by the other control. System abnormality diagnosis device.   2. The rotation angle detection system according to claim 1, wherein when the motor is rotated by the other control, the abnormality diagnosis unit controls the motor to rotate until a predetermined rotation speed is reached. Abnormality diagnosis device.

Images