JP2012098188A - Abnormality diagnostic device in rotation angle detection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an abnormality diagnostic device improving an abnormality detection ratio by narrowing an abnormality detection disabled region in a rotation angle detection system using a one-input and two-output type resolver.SOLUTION: The square sum of two output signals (a SIN signal and a COS signal) of a resolver 11 is calculated as a diagnostic index during a normal time for every rotation angle detection system during an inspection before the shipment of the rotation angle detection system, and an abnormality determination threshold is calculated by making the diagnostic index during the normal time as a reference and is stored in a rewritable non-volatile memory such as an EEPROM 19. Accordingly, the abnormality determination threshold is changed corresponding to a change in the diagnostic index during the normal time according to a circuit error of the system and the abnormality determination threshold is set to a proper value. After that, the square sum of the two output signals of the resolver 11 is calculated as the diagnostic index, the diagnostic index is compared with the abnormality determination threshold, and the presence or absence of disconnection (for instance, disconnection of an excitation signal line, disconnection of a SIN signal line and disconnection of a COS signal line) in the rotation angle detection system is determined.

Description

  The present invention relates to an abnormality diagnosis device for a rotation angle detection system that determines the presence or absence of a disconnection using the sum of squares of two output signals of a 1-input 2-output type resolver as a diagnostic index.

  In general, a rotation angle detection system using a 1-input 2-output type (single-phase excitation 2-phase output type) resolver inputs an excitation signal (sine wave 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 rotation angle 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 rotation angle θ.

  As an abnormality diagnosis technique of a rotation angle detection system using such a resolver, for example, as described in Patent Document 1 (Japanese Patent No. 3136937), two output signals (SIN signal and resolver) are normally output. Focusing on the fact that the sum of squares of the COS signal is constant, if the sum of squares of the two output signals of the resolver is not within the specified range, a disconnection output signal is generated to detect the disconnection of the resolver There is something to do.

Japanese Patent No. 3136937

  By the way, in the rotation angle detection system using the resolver, the present applicant uses the sum of squares of the two output signals of the resolver as a diagnostic index, compares the diagnostic index with a predetermined abnormality determination threshold value, and disconnects (for example, resolver We are studying abnormality diagnosis technology that determines the presence or absence of disconnection of input signal lines and output signal lines. The following new problems were found during the research process.

  As shown in FIG. 2, if it is an ideal system with no circuit error (variation of resistance or capacitor, sampling timing deviation, etc.), the normal diagnostic index (sum of squares of two output signals of resolver) However, as shown in FIG. 3, in the actual system, there is a circuit error within the allowable range in the design, so the diagnosis index rotates even under normal conditions due to the influence of the circuit error. It varies according to the angle θ.

  In consideration of such circumstances, as shown in FIG. 4, in mass production, it is uniform for each rotation angle detection system, and the abnormality is based on the normal diagnostic index when the circuit error is the worst value. By setting the determination threshold, it is possible to avoid erroneous determination that there is an abnormality (disconnected) even though the rotation angle detection system is normal.

  However, as shown in FIG. 4, when the abnormality determination threshold is set based on the normal diagnostic index when the circuit error is the worst value, the abnormal diagnostic index is the normal diagnostic index with respect to the abnormal determination threshold. There is a disadvantage that the area on the same side becomes wider, and the area where abnormality cannot be detected (area where it is erroneously determined that there is no abnormality although the rotation angle detection system is abnormal) becomes wide.

  In addition, the fluctuation cycle of the diagnostic index changes depending on the rotation speed of the rotor, but the rotation speed of the rotor becomes a constant value and the fluctuation cycle of the diagnostic index matches the sampling cycle of the diagnostic index (diagnosis index calculation cycle). If the abnormality detection impossible area is wide when it continues, there is a high possibility that the diagnostic index sampling timing will enter the abnormality detection impossible area, and the state where the diagnostic index is sampled in the abnormality detection non-existence area continues each time. As a result, the abnormality detection rate may decrease.

  Therefore, the problem to be solved by the present invention is to provide an abnormality diagnosing device for a rotation angle detection system capable of narrowing an abnormality detection impossible region and improving an abnormality detection rate.

  In order to solve the above problems, the invention according to claim 1 is applied to a rotation angle detection system that detects a rotation angle based on two output signals of a 1-input 2-output type resolver, and two output signals of the resolver. Is a diagnostic index, and the diagnostic index is compared with an abnormality determination threshold value to determine the presence or absence of disconnection. In this configuration, an abnormality determination threshold value setting unit that sets an abnormality determination threshold value in consideration of the circuit error of the system is provided.

  In this configuration, an abnormality determination threshold value is set for each rotation angle detection system or each production lot of the rotation angle detection system in consideration of the circuit error of the system, so that a diagnosis at normal time is performed according to the circuit error of the system. The abnormality determination threshold can be set to an appropriate value by changing the abnormality determination threshold corresponding to the change of the index. As a result, compared to a system that sets an abnormality determination threshold based on a normal diagnostic index when the circuit error is the worst value, there is no abnormality detection area (no abnormality even though the rotation angle detection system is abnormal). The area where it is erroneously determined that the error is detected can be reduced, and the abnormality detection rate can be improved.

  In the present invention, a circuit error (variation in resistance or capacitor, deviation in sampling timing, etc.) of the system may be actually measured, and the abnormality determination threshold value may be calculated based on the measurement result. As described above, a normal diagnostic index (the sum of squares of two output signals of the resolver) of the rotation angle detection system may be calculated, and the abnormality determination threshold may be calculated based on the normal diagnostic index. . In this way, even if the circuit error of the system is not actually measured, the abnormality determination threshold is changed in response to the change of the normal diagnostic index according to the circuit error of the system, thereby determining the abnormality. The threshold value can be set to an appropriate value corresponding to the normal diagnostic index of the system.

  In this case, as described in claim 3, the abnormality determination threshold value may be calculated and stored in the nonvolatile memory at the time of inspection before the rotation angle detection system is shipped. In this way, an appropriate abnormality determination threshold can be set in advance before the rotation angle detection system is shipped.

  Further, as described in claim 4, each time a predetermined update condition is satisfied, the abnormality determination threshold value may be calculated and updated. In this way, the abnormality determination threshold can be updated in response to changes in the normal diagnostic index due to changes in circuit errors due to temperature changes, deterioration over time, etc., and the abnormality determination threshold is always maintained at an appropriate value. can do.

FIG. 1 is a diagram showing a schematic configuration of a rotation angle detection system in one embodiment of the present invention. FIG. 2 is a diagram for explaining a diagnostic index at normal time in an ideal system. FIG. 3 is a diagram for explaining a diagnostic index at normal time in an actual system. FIG. 4 is a diagram for explaining a problem when an abnormality determination threshold is set with reference to a normal diagnostic index when the circuit error is the worst value. FIG. 5 is a diagram for explaining a method for setting an abnormality determination threshold according to the present embodiment. FIG. 6 is a flowchart for explaining the processing flow of the abnormality determination threshold value setting routine. FIG. 7 is a flowchart for explaining the flow of processing of the abnormality diagnosis routine.

Hereinafter, an embodiment in which the mode for carrying out the present invention is applied to an electric vehicle or a hybrid vehicle using an AC motor as a drive source will be described.
First, a schematic configuration of the rotation angle detection system will be described with reference to FIG.
A resolver 11 for detecting the rotation angle (rotation position) of the rotor is mounted on an AC motor (not shown) used as a power source of the vehicle. This resolver 11 is of a 1-input 2-output type (one-phase excitation two-phase output type) and is connected to an electronic control circuit (hereinafter referred to as “motor controller”) 12 for motor control. The motor controller 12 inputs the excitation signal (sine wave voltage signal) output from the excitation circuit 13 to the resolver 11, and the resolver 11 uses the SIN signal and cos θ obtained by modulating the excitation signal with sin θ according to the rotation angle θ of the rotor. A modulated COS signal is output. The motor controller 12 amplifies the two output signals (SIN signal and COS signal) of the resolver 11 by the differential amplifier circuits 14 and 15, respectively, and inputs them to the R / D converter 16 (resolver digital converter). The D converter 16 converts the two output signals (amplified SIN signal and COS signal) of the resolver 11 into a rotation angle θ (digital signal) and inputs the rotation angle θ (digital signal) to the microcomputer 17 (microcomputer). θ is detected.

  In addition, the motor controller 12 uses the microcomputer 17 to output two output signals (amplified SIN signal and COS signal) of the resolver 11 via the A / D conversion unit 18 in order to perform abnormality diagnosis of the rotation angle detection system. To enter.

  The motor controller 12 calculates a square sum of two output signals (amplified SIN signal and COS signal) of the resolver 11 as a diagnostic index by executing an abnormality diagnostic routine of FIG. 7 to be described later, and the diagnostic index Is compared with the abnormality determination threshold value to determine the presence or absence of disconnection of the rotation angle detection system (for example, disconnection of the excitation signal line, disconnection of the SIN signal line, disconnection of the COS signal line, etc.).

  As shown in FIG. 2, 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 11) ) Should be a constant value, but as shown in FIG. 3, in an actual system, there is a circuit error within a design allowable range. It fluctuates according to the rotation angle θ.

  In consideration of such circumstances, as shown in FIG. 4, in mass production, it is uniform for each rotation angle detection system, and the abnormality is based on the normal diagnostic index when the circuit error is the worst value. By setting the determination threshold, it is possible to avoid erroneous determination that there is an abnormality (disconnected) even though the rotation angle detection system is normal.

  However, as shown in FIG. 4, when the abnormality determination threshold is set based on the normal diagnostic index when the circuit error is the worst value, the abnormal diagnostic index is the normal diagnostic index with respect to the abnormal determination threshold. There is a disadvantage that the area on the same side becomes wider, and the area where abnormality cannot be detected (area where it is erroneously determined that there is no abnormality although the rotation angle detection system is abnormal) becomes wide.

  In addition, the fluctuation cycle of the diagnostic index changes depending on the rotation speed of the rotor, but the rotation speed of the rotor becomes a constant value and the fluctuation cycle of the diagnostic index matches the sampling cycle of the diagnostic index (diagnosis index calculation cycle). If the abnormality detection impossible area is wide when it continues, there is a high possibility that the diagnostic index sampling timing will enter the abnormality detection impossible area, and the state where the diagnostic index is sampled in the abnormality detection non-existence area continues each time. As a result, the abnormality detection rate may decrease.

  As a countermeasure, in this embodiment, an abnormality determination threshold value setting routine of FIG. 6 described later is executed by the motor controller 12 to set an abnormality determination threshold value for each rotation angle detection system in consideration of the circuit error of the system. . As a result, the abnormality determination threshold is changed in accordance with the change in the normal diagnostic index according to the circuit error of the system, and the abnormality determination threshold is set to an appropriate value.

Specifically, as shown in FIG. 5, when the rotation angle detection system is inspected before shipment, the square of two output signals (amplified SIN signal and COS signal) of the resolver 11 for each rotation angle detection system. The sum is calculated as a normal diagnostic index, the abnormality determination threshold is calculated based on the normal diagnostic index, and the rewritable nonvolatile memory such as the EEPROM 19 (stored data is retained even when the motor controller 12 is powered off) Stored in a rewritable memory.
The processing contents of the routines for abnormality diagnosis shown in FIGS. 6 and 7 executed by the motor controller 12 will be described below.

[Abnormal judgment threshold setting routine]
The abnormality determination threshold value setting routine shown in FIG. 6 is executed at the time of inspection before shipment of the rotation angle detection system, and plays a role as abnormality determination threshold value setting means in the claims. When this routine is started, first, in step 101, the AC motor is rotated, and the square sum of the two output signals (amplified SIN signal and COS signal) of the resolver 11 at a predetermined cycle is diagnosed at normal time. The process of calculating as an index is repeated, the waveform of the diagnostic index at normal time is measured, and the normal range of the diagnostic index is measured.

  Thereafter, the process proceeds to step 102, where the abnormality determination threshold value is obtained by subtracting the predetermined value α from the lower limit value of the normal range of the diagnosis index (the bottom value of the waveform of the normal diagnosis index). Stored in the memory. Here, the predetermined value α is set to a value corresponding to, for example, a change in the diagnostic index due to a temperature change, deterioration with time, or the like.

[Abnormal diagnosis routine]
The abnormality diagnosis routine shown in FIG. 7 is repeatedly executed at a predetermined cycle (for example, 2 msec cycle) while the motor controller 12 is powered on. When this routine is started, first, in step 201, the sum of squares of two output signals (amplified SIN signal and COS signal) of the resolver 11 is calculated as a diagnostic index.

  Thereafter, the process proceeds to step 202, where it is determined whether or not the diagnostic index is smaller than an abnormality determination threshold value (an abnormality determination threshold value stored in a nonvolatile memory such as the EEPROM 19). If it is determined in this step 202 that the diagnostic index is equal to or greater than the abnormality determination threshold value, the process proceeds to step 203, where it is determined that there is no abnormality in the rotation angle detection system (no disconnection), and the normal flag is set to ON. Then, this routine is terminated.

  On the other hand, when it is determined in step 202 that the diagnostic index is smaller than the abnormality determination threshold, the process proceeds to step 204, and the state where the diagnostic index is smaller than the abnormality determination threshold is a predetermined number of times (for example, 10 times). It is determined whether or not it is continuous. If it is determined in step 204 that the diagnosis index is smaller than the abnormality determination threshold value for a predetermined number of times, this routine is terminated while the abnormality flag is kept off.

  Thereafter, if it is determined in step 204 that the state where the diagnostic index is smaller than the abnormality determination threshold value has continued for a predetermined number of times, the process proceeds to step 205, where it is determined that there is an abnormality in the rotation angle detection system (there is a disconnection). The abnormality flag is set to ON, and a warning lamp (not shown) provided on the instrument panel of the driver's seat is turned on or blinked, or a warning display section (not shown) of the instrument panel of the driver's seat is used. ), The driver is warned and the abnormality information (abnormality code or the like) is stored in a rewritable nonvolatile memory such as a backup RAM (not shown), and this routine is terminated.

  In the routine of FIG. 7, when the state where the diagnostic index is smaller than the abnormality determination threshold value continues for a predetermined number of times, it is determined that the rotation angle detection system is abnormal (disconnected). However, the present invention is not limited to this, and may be changed as appropriate. For example, when the state in which the diagnostic index is smaller than the abnormality determination threshold has exceeded a predetermined number of times within a predetermined period, there is an abnormality in the rotation angle detection system (with disconnection). May be determined.

  In the present embodiment described above, for each rotation angle detection system, a diagnostic index when the system is normal (the sum of squares of two output signals of the resolver 11) is calculated, and an abnormality occurs based on the normal diagnostic index. Since the determination threshold value is calculated, the abnormality determination threshold value is changed in response to the change of the normal diagnostic index according to the circuit error of the system without actually measuring the system circuit error. Thus, the abnormality determination threshold value can be set to an appropriate value corresponding to the diagnostic index when the system is normal. As a result, compared to a system that sets an abnormality determination threshold based on a normal diagnostic index when the circuit error is the worst value, there is no abnormality detection area (no abnormality even though the rotation angle detection system is abnormal). The area where it is erroneously determined that the error is detected can be reduced, and the abnormality detection rate can be improved.

  In this embodiment, the abnormality determination threshold value is calculated and stored in a rewritable nonvolatile memory such as the EEPROM 19 at the time of inspection before shipment of the rotation angle detection system. An appropriate abnormality determination threshold value can be set.

  In the above-described embodiment, for each rotation angle detection system, a normal diagnostic index of the system is calculated, and the abnormality determination threshold is calculated based on the normal diagnostic index. However, the present invention is not limited to this. Instead, for example, for each production lot of the rotation angle detection system, a diagnostic index when the system is normal may be calculated, and the abnormality determination threshold may be calculated based on the normal diagnostic index.

  Alternatively, for each rotation angle detection system or each production lot of the rotation angle detection system, system circuit errors (resistance and capacitor variations, sampling timing deviation, etc.) are actually measured and based on the measurement results. An abnormality determination threshold value may be calculated.

  In the above embodiment, the abnormality determination threshold value is calculated and stored in a rewritable non-volatile memory such as the EEPROM 19 at the time of inspection before shipment of the rotation angle detection system. Further, a predetermined update condition is satisfied. The abnormality determination threshold value may be calculated and updated every time (for example, every time it is determined that there is no abnormality in the rotation angle detection system, every time a predetermined time elapses, every time a predetermined distance is traveled, etc.). In this way, the abnormality determination threshold can be updated in response to changes in the normal diagnostic index due to changes in circuit errors due to temperature changes, deterioration over time, etc., and the abnormality determination threshold is always maintained at an appropriate value. can do.

  In the above embodiment, the present invention is applied to a rotation angle detection system for an AC motor mounted on an electric vehicle or a hybrid vehicle. However, the present invention is not limited to this, and rotation angle detection using a 1-input 2-output type resolver. The present invention can be applied to any system.

  DESCRIPTION OF SYMBOLS 11 ... Resolver, 12 ... Motor controller (abnormality determination threshold value setting means), 13 ... Excitation circuit, 14, 15 ... Differential amplifier circuit, 16 ... R / D converter, 17 ... Microcomputer, 19 ... EEPROM (nonvolatile memory)

Claims (4)

It is applied to a rotation angle detection system that detects a rotation angle based on two output signals of a 1-input 2-output type resolver. The sum of squares of the two output signals of the resolver is used as a diagnostic index, and the diagnostic index is determined to be abnormal. In the abnormality diagnosis device of the rotation angle detection system that determines the presence or absence of disconnection compared to a threshold value,
A rotation angle comprising an abnormality determination threshold setting means for setting the abnormality determination threshold in consideration of a circuit error of each rotation angle detection system or each manufacturing lot of the rotation angle detection system. Abnormality diagnosis device for detection system.   2. The abnormality determination threshold setting unit calculates a normal diagnostic index of the rotation angle detection system, and calculates the abnormal determination threshold based on the normal diagnostic index. Abnormality diagnosis device for rotation angle detection system.   3. The abnormality of the rotation angle detection system according to claim 2, wherein the abnormality determination threshold value setting means calculates the abnormality determination threshold value and stores the abnormality determination threshold value in a nonvolatile memory at the time of inspection before shipment of the rotation angle detection system. Diagnostic device.   The abnormality diagnosis device for a rotation angle detection system according to claim 2 or 3, wherein the abnormality determination threshold value setting means calculates and updates the abnormality determination threshold value every time a predetermined update condition is satisfied.

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