Resolver exciting device and excitation method

Abstract

To appropriately control the exciting state of a resolver in response to an abnormality state when excitation abnormality or detection abnormality occurs.SOLUTION: A determination unit 32 determines which excitation state to be selected from continuous excitation for outputting an excitation signal continuously, intermittent excitation for outputting an excitation signal intermittently, and excitation stoppage for stopping excitation signal output, in response to an abnormality state detected by an excitation abnormality detection unit 26 and a detection abnormality detection unit 28. Therefore, when at least one of the excitation abnormality of an excitation-phase coil 14, the detection abnormality of a Sin-phase coil 16, and the detection abnormality of a Cos-phase coil 18 occurs, it is made possible to excite a resolver 10 in an excitation state suitable for the abnormality state that has occurred.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an excitation device for a resolver having an excitation phase coil to which an excitation signal is applied, and a Sin phase coil and a Cos phase coil that output a detection signal, and an excitation device for a resolver. [Background technology]

[0002] For example, Patent Document 1 discloses a resolver drive device. The resolver drive device described in Patent Document 1 is mounted on a vehicle. When the vehicle is moving, an excitation signal is output to the resolver in a constant excitation mode in which an excitation signal is output constantly. On the other hand, when the vehicle is stopped, an excitation signal is output to the resolver in an intermittent excitation mode in which an excitation signal is output intermittently. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5763420 Summary of the Invention [Problem to be solved by the invention]

[0004] In the resolver drive device of Patent Document 1, when the vehicle is stopped and the need for angle detection is low, an intermittent excitation mode is set to reduce the power required for exciting the resolver. However, the resolver drive device of Patent Document 1 does not take into consideration how to deal with cases in which an excitation abnormality or a detection abnormality occurs in the resolver.

[0005] For example, if an excitation abnormality occurs in which the wiring connected to the excitation phase has a ground fault, and excitation is continued in the constant excitation mode, a large current flows in the circuit that outputs the excitation signal, resulting in excessive power loss. On the other hand, if a detection abnormality occurs in a detection phase such as the Sin phase or Cos phase, the angle cannot be detected, but the excessive power loss described above does not occur. For this reason, even if excitation is performed in the constant excitation mode, this does not pose a major problem.

[0006] The present disclosure has been made in consideration of the above-mentioned points, and aims to provide a resolver excitation device that is capable of appropriately controlling the excitation state of a resolver depending on the nature of an excitation abnormality or detection abnormality when such an abnormality occurs. [Means for solving the problem]

[0007] In order to achieve the above object, a resolver excitation device according to the present disclosure is an excitation device for a resolver (10) having an excitation phase coil (14) to which an excitation signal is applied, and a Sin phase coil (16) and a Cos phase coil (18) which output a detection signal, an abnormality detection unit (26, 28) that detects the occurrence of at least one of an excitation abnormality in an excitation phase coil, a detection abnormality in a Sin phase coil, and a detection abnormality in a Cos phase coil; a determination unit (32) that determines which excitation state to use, among continuous excitation in which an excitation signal is output continuously, intermittent excitation in which an excitation signal is output intermittently, and excitation stop in which output of the excitation signal is stopped, according to the type of the abnormality detected by the abnormality detection unit; and an excitation signal control unit (22, 24, 34, 36, 38) that controls the excitation signal to be output to the excitation phase coil in accordance with the excitation state determined by the determination unit.

[0008] A resolver excitation method according to the present disclosure is an excitation method implemented by an excitation device (20) that excites a resolver (10) having an excitation phase coil (14) to which an excitation signal is applied, and a Sin phase coil (16) and a Cos phase coil (18) that output a detection signal, Detecting the occurrence of at least one of an excitation abnormality in an excitation phase coil, a detection abnormality in a Sin phase coil, and a detection abnormality in a Cos phase coil; determining whether the excitation state should be a continuous excitation state in which an excitation signal is continuously output, an intermittent excitation state in which an excitation signal is intermittently output, or an excitation stop state in which output of the excitation signal is stopped, according to the type of the detected abnormality; The method further comprises controlling an excitation signal to be output to an excitation phase coil in accordance with the determined excitation state.

[0009] As described above, in the resolver excitation device and excitation method disclosed herein, depending on the mode of the detected abnormality, it is determined which excitation state to use: continuous excitation in which an excitation signal is output continuously, intermittent excitation in which an excitation signal is output intermittently, or excitation stop in which output of an excitation signal is stopped. Therefore, when at least one of an excitation abnormality in the excitation phase coil, a detection abnormality in the Sin phase coil, and a detection abnormality in the Cos phase coil occurs, it is possible to excite the resolver in an excitation state suitable for the mode of the abnormality that has occurred.

[0010] The reference numbers in parentheses above are merely an example of a correspondence with a specific configuration in an embodiment described below, in order to facilitate understanding of the present disclosure, and are not intended to limit the scope of the present disclosure in any way.

[0011] In addition, technical features described in each claim in addition to the features of the present disclosure described above will become apparent from the description of the embodiments described below and the accompanying drawings. [Brief description of the drawings]

[0012] [Figure 1] 1 is a configuration diagram illustrating a schematic configuration of a resolver excitation device according to a first embodiment. [Diagram 2] 4A to 4C are waveform diagrams showing normal Sin phase detection signals and Cos phase detection signals. [Diagram 3] 11 is a waveform diagram showing an abnormal Sin phase detection signal and an abnormal Cos phase detection signal. FIG. [Figure 4] 11 is a waveform diagram showing a normal Sin phase detection signal and an abnormal Cos phase detection signal. FIG. [Diagram 5] 13 is a diagram showing an example of a judgment table used by a determination unit when determining an excitation state; FIG. [Figure 6] 5 is a waveform diagram showing an excitation output pattern and an output waveform to an excitation phase coil when continuous excitation is performed. FIG. [Figure 7] 10 is a waveform diagram showing an excitation output pattern and an output waveform to an excitation phase coil when excitation is stopped. FIG. [Figure 8] 5 is a waveform diagram showing an excitation output pattern and an output waveform to an excitation phase coil when intermittent excitation is performed. FIG. [Figure 9] 10A and 10B are diagrams for explaining excitation-on periods and excitation-off periods in intermittent excitation. [Figure 10] 4 is a flowchart showing a process executed to determine an excitation state in an excitation device. [Figure 11] FIG. 4 is a diagram illustrating a first control example regarding determination of an excitation state by an excitation device. [Figure 12] FIG. 11 is a diagram illustrating a second control example regarding determination of an excitation state by an excitation device. [Figure 13] FIG. 13 is a diagram illustrating a third control example regarding determination of an excitation state by an excitation device. [Figure 14] FIG. 11 is a configuration diagram illustrating a schematic configuration of a resolver excitation device according to a second embodiment. [Figure 15] FIG. 11 is a configuration diagram illustrating a schematic configuration of a resolver excitation device according to a third embodiment. [Figure 16] FIG. 11 is a configuration diagram illustrating a schematic configuration of a resolver excitation device according to a fourth embodiment. [Figure 17] FIG. 13 is a configuration diagram illustrating a schematic configuration of a resolver excitation device according to a fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, preferred embodiments of the present disclosure will be described with reference to the drawings. Note that the same or similar configurations may be omitted from description by assigning the same reference number across multiple drawings. When only a portion of a configuration is described in each embodiment, the configuration of another embodiment described above may be applied to the other portion of the configuration. In addition to the combination of configurations explicitly stated in the description of each embodiment, configurations of multiple embodiments may be partially combined together even if not explicitly stated, as long as there is no particular problem with the combination.

[0014] (First embodiment) FIG. 1 is a configuration diagram that shows a schematic configuration of an excitation device 20 of a resolver 10 according to the first embodiment.

[0015] The resolver 10 is a sensor that detects the rotation angle of a motor (not shown). The rotor 12 of the resolver 10 is attached to the rotating shaft of the motor and rotates in the same manner as the motor. The resolver 10 includes an excitation phase coil 14 and a pair of detection phase coils, a Sin phase coil 16 and a Cos phase coil 18. The excitation phase coil 14 may be provided on the rotor 12 of the resolver 10, or may be provided on the stator of the resolver 10. When the excitation phase coil 14 is provided on the stator of the resolver 10, the resolver becomes a VR type resolver that utilizes reluctance changes in the air gap between the rotor 12 and the stator.

[0016] The excitation phase coil 14 is excited by a sine-wave excitation signal. When the excitation phase coil 14 is excited by the excitation signal, a magnetic flux is generated from the excitation phase coil 14. The magnetic flux generated in the excitation phase coil 14 is linked to the sine phase coil 16 and the cos phase coil 18. In response to the rotation of the rotor 12, the magnetic flux linkage of the sine phase coil 16 and the cos phase coil 18 due to the magnetic flux of the excitation phase coil 14 changes periodically. As a result, a sine-wave sine phase detection signal and a cos phase detection signal are induced in the sine phase coil 16 and the cos phase coil 18 in response to the rotation of the rotor 12.

[0017] The sine phase coil 16 and the cos phase coil 18 are arranged such that the phases of the sine phase detection signal and the cos phase detection signal generated in the sine phase coil 16 and the cos phase coil 18 are shifted from each other by "π / 2". Therefore, if the excitation signal of the excitation phase coil 14 is "sinωt", the sine phase detection signal and the cos phase detection signal detected by the sine phase coil 16 and the cos phase coil 18 are "sinθ×sinωt" and "cosθ×sinωt", respectively. θ indicates the angle of the rotor 12. The rotation angle of the motor can be calculated based on the sine phase detection signal and the cos phase detection signal of the sine phase coil 16 and the cos phase coil 18. Note that the rotor 12 may be configured to have a plurality of convex shapes formed on the outer periphery thereof, so that a plurality of periods of frequency fluctuation occurs per one rotation of the rotor 12.

[0018] The excitation device 20 of the resolver 10 generates the above-mentioned excitation signal and outputs it to the excitation phase coil 14. The excitation device 20 also calculates the rotation angle of the motor based on the sine phase detection signal and the cosine phase detection signal by the sine phase coil 16 and the cosine phase coil 18. The excitation device 20 also detects the occurrence of at least one of an excitation abnormality by the excitation phase coil 14 and a detection abnormality in the sine phase coil 16 and the cosine phase coil 18, and determines which excitation state to use, that is, continuous excitation in which an excitation signal is continuously output, intermittent excitation in which an excitation signal is intermittently output, or excitation stop in which output of an excitation signal is stopped, according to the mode of the detected abnormality. The excitation device 20 then controls the excitation signal to be output to the excitation phase coil 14 of the resolver 10 according to the determined excitation state. In this way, when at least one of the excitation abnormality in the excitation phase coil 14, the detection abnormality in the Sin phase coil 16, and the detection abnormality in the Cos phase coil 18 occurs, the excitation device 20 is able to excite the resolver 10 in an excitation state appropriate to the nature of the abnormality that has occurred.

[0019] In order to perform the above-mentioned functions, the excitation device 20 has an excitation source signal generating section 22, an amplifier section 24, an excitation abnormality detecting section 26, a detection abnormality detecting section 28, an R / D converter 30, a determination section 32, and an excitation output pattern generating section 34. The excitation device 20 can be configured by a known computer having at least one processor such as a CPU, and memories such as a ROM and a RAM. The excitation device 20 can be configured to perform the functions of the excitation source signal generating section 22, the excitation abnormality detecting section 26, the detection abnormality detecting section 28, the determination section 32, and the excitation output pattern generating section 34 by having at least one processor execute a program stored in the memory.

[0020] The excitation original signal generating unit 22 generates and outputs an excitation original signal, which is a sine wave signal, during an excitation-on period when excitation-on is instructed by the excitation output pattern generating unit 34. On the other hand, the excitation original signal generating unit 22 stops outputting the excitation original signal during an excitation-off period when excitation-off is instructed by the excitation output pattern generating unit 34.

[0021] The amplifier 24 is an amplifier circuit that includes, for example, an operational amplifier, amplifies the excitation source signal generated by the excitation source signal generator 22 to generate an excitation signal, and outputs the excitation signal to the excitation phase coil 14. The excitation signal output by the amplifier 24 causes the excitation signal to flow through the excitation phase coil 14, exciting the excitation phase coil 14. In this embodiment, the excitation source signal generator 22, the amplifier 24, and the excitation output pattern generator 34 function as an excitation signal controller in the claims and control the excitation signal to be output to the excitation phase coil 14.

[0022] The excitation abnormality detection unit 26 detects an abnormality in the excitation by the excitation phase coil 14. For example, the excitation abnormality detection unit 26 takes in the excitation signal output from the amplifier unit 24, and can detect the excitation abnormality based on whether or not the frequency of the excitation signal (sine wave signal) is within the frequency range of a normal excitation signal and / or whether or not the magnitude of the amplitude of the excitation signal is within the amplitude range of a normal excitation signal. When the excitation abnormality detection unit 26 detects an excitation abnormality, it notifies the determination unit 32 of the detection result of the excitation abnormality together with information indicating the state of the detected excitation abnormality. When the excitation abnormality detection unit 26 does not detect an excitation abnormality, it may notify the determination unit 32 that the excitation is normal.

[0023] The above-mentioned excitation abnormality may occur due to a break in the path from the amplifier 24 to the excitation phase coil 14, a ground fault, a power fault, or a malfunction of the excitation source signal generator 22 and / or the amplifier 24.

[0024] The detection abnormality detection unit 28 detects detection abnormalities in the Sin phase coil 16 and the Cos phase coil 18. The detection abnormality detection unit 28 takes in the Sin phase detection signal and the Cos phase detection signal of the Sin phase coil 16 and the Cos phase coil 18, respectively. The detection abnormality detection unit 28 can detect a detection abnormality, for example, based on whether the amplitude of the Sin phase detection signal and the Cos phase detection signal exceeds a predetermined threshold (zero fixation threshold). However, the detection abnormality detection unit 28 may detect a detection abnormality other than the zero fixation, such as a detection abnormality in which the Sin phase detection signal and / or the Cos phase detection signal is stuck at a value exceeding the zero fixation threshold due to a power short.

[0025] As an example, as shown in FIG. 2, when the peak values ​​of the Sin phase detection signal and the Cos phase detection signal of each of the Sin phase coil 16 and the Cos phase coil 18 are both greater than the zero fixation threshold while the Sin phase detection signal and the Cos phase detection signal of each of the Sin phase coil 16 and the Cos phase coil 18 are periodically changing, the detection abnormality detection unit 28 judges that no detection abnormality has occurred and that the detection is normal. When the detection abnormality detection unit 28 judges that the detection is normal, the detection abnormality detection unit 28 may notify the decision unit 32 that the detection is normal. On the other hand, as shown in FIG. 3, when the peak values ​​of the Sin phase detection signal and the Cos phase detection signal of each of the Sin phase coil 16 and the Cos phase coil 18 are both not greater than the zero fixation threshold, and when the peak value of one of the detection signals of the Sin phase coil 16 and the Cos phase coil 18 is greater than the zero fixation threshold but the peak value of the other detection signal is not greater than the zero fixation threshold, as shown in FIG. 4, the detection abnormality detection unit 28 judges that a detection abnormality has occurred. When the detection abnormality detection unit 28 detects a detection abnormality, it notifies the decision unit 32 of the detection result of the detection abnormality together with information indicating the state of the detected detection abnormality.

[0026] As shown in Figures 3 and 4, a detection abnormality in which the peak values ​​of the Sin phase detection signal and / or Cos phase detection signal of the Sin phase coil 16 and / or Cos phase coil 18 do not exceed the zero fixation threshold may occur when the Sin phase coil 16 and / or Cos phase coil 18 are broken, when the Sin phase coil 16 and / or Cos phase coil 18 are grounded, when the Sin phase coil 16 and the Cos phase coil 18 are short-circuited to each other, or when the output lines of the Sin phase coil 16 and / or the output lines of the Cos phase coil 18 are short-circuited to each other. However, as shown in FIG. 3, a detection abnormality in which the peak values ​​of the sine phase detection signal and the cos phase detection signal of the sine phase coil 16 and the cos phase coil 18 do not exceed the zero stick threshold can actually occur when an open circuit, a ground fault, or a mutual short circuit occurs in the sine phase coil 16 and the cos phase coil 18, or when a short circuit occurs between the output lines of the sine phase coil 16 and the cos phase coil 18, or when the rotor 12 stops at an angular position where one of the sine phase coil 16 and the cos phase coil 18 is open circuited or has a ground fault and the peak value of the detection signal of the other is below the zero stick threshold.

[0027] The R / D converter 30 calculates the rotation angle of the rotor 12, i.e., the rotation angle of the motor, based on the peak values ​​of the sine phase detection signals and the cos phase detection signals of the sine phase coil 16 and the cos phase coil 18, respectively. For example, the R / D converter 30 takes in the detection signals of the sine phase coil 16 and the cos phase coil 18, and uses an A / D converter (not shown) to convert each detection signal into a digital signal to identify the peak value. The R / D converter 30 can calculate the rotation angle of the motor based on the peak values ​​of the sine phase detection signal and the cos phase detection signal. The A / D converter may be built into the R / D converter 30 or may be provided externally.

[0028] The decision unit 32 judges the type of abnormality related to the excitation and detection of the resolver 10 based on the notification from the excitation abnormality detection unit 26 and the notification from the detection abnormality detection unit 28, and determines which excitation state to use depending on the judgment result: continuous excitation, in which an excitation signal is continuously output, intermittent excitation, in which an excitation signal is intermittently output, or excitation stop, in which the output of the excitation signal is stopped.

[0029] The process in the determination unit 32 will be described in detail below. First, the determination unit 32 determines the type of excitation abnormality based on the notification from the excitation abnormality detection unit 26. Furthermore, the determination unit 32 also determines the type of detection abnormality based on the notification from the detection abnormality detection unit 28. Then, the determination unit 32 comprehensively determines the type of abnormality related to excitation and detection of the resolver 10 based on the determined type of excitation abnormality and type of detection abnormality.

[0030] Regarding the mode of the excitation abnormality, when the determination unit 32 is notified by the excitation abnormality detection unit 26 of an abnormality in which the frequency of the excitation signal greatly exceeds the upper limit of the normal frequency range or an abnormality in which the amplitude of the excitation signal greatly exceeds the upper limit of the normal amplitude range (i.e., the amplitude is very large), the determination unit 32 can determine that an excitation abnormality has been confirmed as the mode of the excitation abnormality, assuming that a failure has occurred in the excitation source signal generation unit 22 and / or the amplification unit 24, or that a short circuit to the power supply has occurred in the excitation phase coil 14. However, the determination unit 32 may also determine that an excitation abnormality has been confirmed when the notification of the abnormality described above continues for a first predetermined time.

[0031] In addition, when the determination unit 32 is notified by the excitation abnormality detection unit 26 of an abnormality in which the frequency of the excitation signal is slightly above the upper limit or slightly below the lower limit of the normal frequency range, and / or an abnormality in which the amplitude of the excitation signal is slightly above the upper limit or slightly below the lower limit of the normal amplitude range, the determination unit 32 determines that the type of excitation abnormality is an unconfirmed excitation abnormality. In other words, when the deviation of the frequency or amplitude from the normal range is not so large that it is clearly regarded as abnormal, it is determined that there is a possibility of an excitation abnormality, but that it has not yet been confirmed.

[0032] In this way, the type of excitation abnormality determined by the determination unit 32 includes a confirmed excitation abnormality and an unconfirmed excitation abnormality.

[0033] Regarding the mode of the detection anomaly, for example, when the detection anomaly detector 28 notifies the determination unit 32 of detection anomalies in the Sin phase coil 16 and the Cos phase coil 18 at the same time, the determination unit 32 determines that the detection anomaly has occurred in both the Sin phase coil 16 and the Cos phase coil 18. However, in this case, as described above, while there is a possibility that an open circuit, a ground fault, a mutual short circuit, or a short circuit between the output lines of both the Sin phase coil 16 and the Cos phase coil 18 has actually occurred, there is also a possibility that an open circuit or a ground fault has occurred in one of the Sin phase coil 16 and the Cos phase coil 18, and the rotor 12 has stopped at an angular position where the detection signal of the other is equal to or lower than the zero fixation threshold.

[0034] In addition, for example, when the detection abnormality detection unit 28 notifies the determination unit 32 of a detection abnormality in either the Sin phase coil 16 or the Cos phase coil 18, the determination unit 32 determines that a detection abnormality has occurred in either the Sin phase coil 16 or the Cos phase coil 18 as the type of detection abnormality.

[0035] In this way, the detection abnormality determined by the determination unit 32 includes a detection abnormality in both the sine phase coil 16 and the cos phase coil 18, and a detection abnormality in either the sine phase coil 16 or the cos phase coil 18.

[0036] The determination unit 32 then determines the overall abnormality state related to the excitation and detection of the resolver 10 based on the determined excitation abnormality state and detection abnormality state. The determination unit 32 then determines which excitation state of the excitation phase coil 14 should be, among continuous excitation, intermittent excitation, and excitation stop, depending on the determination result of the overall abnormality state related to the excitation and detection of the resolver 10. Fig. 5 shows an example of a determination table used by the determination unit 32 when determining the excitation state.

[0037] As shown in the judgment table of Figure 5, if the excitation phase coil 14 is normally excited and the detection by the Sin phase coil 16 and the Cos phase coil 18 is also normally performed, the decision unit 32 decides that no abnormality has occurred and therefore that the excitation state of the excitation phase coil 14 is to be continuous excitation.

[0038] On the other hand, when an excitation abnormality is confirmed as the type of excitation abnormality, the decision unit 32 determines that an abnormality has occurred that requires excitation to be stopped as the type of abnormality related to the excitation and detection of the resolver 10, regardless of the type of detection abnormality in the Sin phase coil 16 and the Cos phase coil 18, and decides to change the excitation state to excitation stop.

[0039] Furthermore, when the excitation is normal or an undetermined excitation abnormality occurs and a detection abnormality occurs in either the Sin phase coil 16 or the Cos phase coil 18, the decision unit 32 determines that the abnormality state regarding the excitation and detection of the resolver 10 is such that continuous excitation will not result in a large power loss, and determines to set the excitation state to continuous excitation. In this case, since normal detection is being performed in either the Sin phase coil 16 or the Cos phase coil 18, even if an undetermined excitation abnormality occurs, it can be considered that it is temporary or minor and that no definite excitation abnormality has occurred. Therefore, even if continuous excitation is performed on the excitation phase coil 14, it is considered that there is no risk of excessive power loss occurring in the amplifier unit 24, etc.

[0040] However, if the unconfirmed excitation abnormality continues for a second predetermined time (longer than the first predetermined time), the decision unit 32 may determine that the excitation abnormality has been confirmed and decide to change the excitation state to excitation stop. Also, if a detection abnormality occurs in either the Sin phase coil 16 or the Cos phase coil 18, the rotation angle of the motor cannot be detected even if continuous excitation is performed. Therefore, the decision unit 32 may decide to change the excitation state to excitation stop instead of continuous excitation.

[0041] On the other hand, when the excitation is normal or an undetermined excitation abnormality occurs and detection abnormalities occur in both the Sin phase coil 16 and the Cos phase coil 18, the determination unit 32 determines that the excitation state is to be intermittent excitation.

[0042] Here, particularly when an undetermined excitation anomaly occurs in which the amplitude of the excitation signal becomes smaller than the normal range, and a detection anomaly occurs in both the sine phase coil 16 and the cos phase coil 18 in which the amplitude is below the zero fixation threshold, it is not possible to determine whether an anomaly such as a disconnection or ground fault has occurred in the excitation phase coil 14, causing a detection anomaly in both the sine phase coil 16 and the cos phase coil 18, or whether the excitation anomaly is temporary and an anomaly actually occurs in both the sine phase coil 16 and the cos phase coil 18. Therefore, it is necessary to continue exciting the excitation phase coil 14 in order to identify the location of the anomaly.

[0043] However, if continuous excitation is performed when a ground fault has occurred in the wiring connected to the excitation phase coil 14, the resistance due to the excitation phase coil 14 will disappear, causing a large current to flow through the amplifier section 24, which may result in excessive power loss.

[0044] In contrast, by the decision unit 32 deciding to set the excitation state to intermittent excitation, it becomes possible to suppress power loss in the amplifier unit 24 and the like, as compared to continuous excitation. Also, in the amplifier unit 24, there is no need for a margin design that can withstand excessive power loss, so it is possible to reduce the cost and size of the amplifier unit 24.

[0045] In addition, when an unconfirmed excitation abnormality occurs in which the amplitude of the excitation signal is reduced, and detection abnormalities occur in both the Sin phase coil 16 and the Cos phase coil 18, if it is determined by performing intermittent excitation that there is an abnormality in the excitation by the excitation phase coil 14, the decision unit 32 can decide to change the excitation state to excitation stop. Furthermore, if it is found by the intermittent excitation that the excitation is normal but there is a detection abnormality in either the Sin phase coil 16 or the Cos phase coil 18, the decision unit 32 can decide to change the excitation state to continuous excitation or excitation stop. Similarly, if it is found by the intermittent excitation that the excitation is normal but there is a detection abnormality in both the Sin phase coil 16 and the Cos phase coil 18, the decision unit 32 may keep the excitation state as intermittent excitation, or may change the excitation state to continuous excitation or excitation stop.

[0046] For the same reason, when excitation is normal and detection abnormalities have occurred in both the Sin phase coil 16 and the Cos phase coil 18, the decision unit 32 decides to perform intermittent excitation, thereby making it possible to determine whether abnormalities have actually occurred in both the Sin phase coil 16 and the Cos phase coil 18, or whether the detection abnormality in one of them is temporary due to the stopped position of the rotor 12. When the detection abnormality in one of the Sin phase coil 16 and the Cos phase coil 18 is no longer detected while intermittent excitation is being performed and only the detection abnormality in the other is detected, the decision unit 32 decides to change the excitation state to continuous excitation or excitation stop.

[0047] In addition, when the excitation is normal, there is no risk of excessive power loss even if continuous excitation is performed. Therefore, even when the excitation is normal and detection abnormalities occur in both the Sin phase coil 16 and the Cos phase coil 18, the determination unit 32 may determine that the excitation state is to be continuous excitation.

[0048] The excitation output pattern generating unit 34 selects and outputs either an excitation-on signal that instructs the excitation source signal generating unit 22 to turn on excitation or an excitation-off signal that instructs the excitation source signal generating unit 22 to turn off excitation, so that an excitation signal is output from the amplifying unit 24 according to the excitation state determined by the determining unit 32. Specifically, when the determining unit 32 determines that the excitation state is to be continuous excitation, the excitation output pattern generating unit 34 continuously outputs an excitation-on signal to the excitation source signal generating unit 22 as shown in FIG. 6(b). During the excitation-on period in which the excitation-on signal is output, the excitation source signal generating unit 22 continuously outputs an excitation source signal having a sine waveform. As a result, the amplifying unit 24 continuously outputs an excitation signal to the excitation phase coil 14 as shown in FIG. 6(a), so that an excitation state according to continuous excitation can be realized.

[0049] Furthermore, when the determination unit 32 determines that the excitation state is to be excitation stopped, the excitation output pattern generation unit 34 outputs an excitation off signal to the excitation source signal generation unit 22 as shown in Fig. 7(b). During the excitation off period in which the excitation off signal is being output, the excitation source signal generation unit 22 stops outputting the excitation source signal. As a result, the amplification unit 24 stops outputting the excitation signal to the excitation phase coil 14 as shown in Fig. 7(a), thereby realizing an excitation state according to the excitation stop.

[0050] Furthermore, when the determination unit 32 determines that the excitation state is to be intermittent excitation, the excitation output pattern generation unit 34 alternately outputs an excitation-on signal and an excitation-off signal to the excitation source signal generation unit 22 as shown in FIG. 8(b). The excitation source signal generation unit 22 outputs the excitation source signal during an excitation-on period Ton when the excitation-on signal is output, and stops outputting the excitation source signal during an excitation-off period Toff when the excitation-off signal is output. As a result, the amplification unit 24 outputs an excitation signal to the excitation phase coil 14 only during the excitation-on period Ton, as shown in FIG. 8(a), and stops outputting the excitation signal during the excitation-off period Toff, thereby realizing an excitation state according to intermittent excitation.

[0051] The excitation-on period Ton in intermittent excitation is set to a time at least longer than the excitation start-up time shown in Fig. 9. The excitation start-up time is defined as at least the time during which a Sin phase detection signal and a Cos phase detection signal are induced in the Sin phase coil 16 and the Cos phase coil 18, respectively, by energization of an excitation signal to the excitation phase coil 14. By setting the excitation-on period Ton to a time longer than the excitation start-up time, it is possible to verify the authenticity of detection anomalies in the Sin phase coil 16 and the Cos phase coil 18 based on the Sin phase detection signal and the Cos phase detection signal while intermittent excitation is being performed.

[0052] Furthermore, the excitation-on period Ton in intermittent excitation is preferably set to a time longer than the sum of the excitation start-up time and the R / D converter settling time, as shown in Fig. 9. The R / D converter settling time is defined as the time from when a sine phase detection signal and a cosine phase detection signal are input to the R / D converter 30 until the R / D converter 30 calculates and outputs an angle corresponding to the input sine phase detection signal and cos phase detection signal.

[0053] When the exciter 20 starts to energize the excitation phase coil 14 of the resolver 10 and starts to detect the rotation angle of the motor by the resolver 10, the exciter 20 executes a startup sequence to detect the angle after the above-mentioned excitation start-up time and R / D converter settling time have elapsed. By setting the excitation-on period Ton in intermittent excitation to a time longer than the sum of the excitation start-up time and the R / D converter settling time, the exciter 20 can use the normal startup sequence as it is even during the excitation-on period in intermittent excitation.

[0054] Moreover, it is preferable that the excitation-on period ratio (Ton / (Ton+Toff)) in the intermittent excitation is set so that even if a large current flows through the amplifier unit 24 due to a ground fault, the power loss due to the excitation-on period Ton is smaller than the allowable power loss of the amplifier unit 24. This makes it possible to reliably protect the amplifier unit 24 even if a large current flows.

[0055] Next, referring to the flowchart of FIG. 10, an example of a process will be described in which the excitation device 20 detects that at least one of an excitation abnormality in the excitation phase coil 14 and a detection abnormality in the Sin phase coil 16 and the Cos phase coil 18 has occurred, and determines which excitation state should be selected, among continuous excitation, intermittent excitation, and excitation stop, depending on the nature of the detected abnormality.

[0056] In step S100, the excitation device 20 determines whether or not an excitation abnormality has been confirmed. As described above, an excitation abnormality is confirmed when the frequency and / or amplitude of the excitation signal greatly exceed their respective normal ranges, or when the deviation from the normal range is not large but the state continues for a second predetermined time. If it is determined in step S100 that an excitation abnormality has been confirmed, the excitation device 20 proceeds to step S110. On the other hand, if the excitation device 20 determines that the excitation is normal or that an unconfirmed excitation abnormality has occurred, it proceeds to step S120.

[0057] In step S110, since the excitation abnormality has been confirmed, the excitation device 20 determines the excitation state to be excitation stopped, and outputs the determined excitation state (excitation stopped) to the excitation output pattern generating unit .

[0058] In step S120, the exciter 20 determines whether or not a detection abnormality has been detected in both the sine phase coil 16 and the cos phase coil 18. If it is determined that a detection abnormality has been detected in both the sine phase coil 16 and the cos phase coil 18, the exciter 20 proceeds to step S130. On the other hand, if no detection abnormality has been detected or a detection abnormality has been detected in only one of the sine phase coil 16 and the cos phase coil 18, the exciter 20 proceeds to step S140.

[0059] In step S130, since detection abnormalities have been detected in both the Sin phase coil 16 and the Cos phase coil 18, the exciter 20 determines the excitation state to be intermittent excitation and outputs the determined excitation state (intermittent excitation) to the excitation output pattern generator 34. In step S140, since no detection abnormality has been detected or a detection abnormality has been detected in only one of the Sin phase coil 16 and the Cos phase coil 18, the exciter 20 determines the excitation state to be continuous excitation and outputs the determined excitation state (continuous excitation) to the excitation output pattern generator 34.

[0060] Next, some examples of control by the excitation device 20 will be described with reference to FIGS.

[0061] Case 1 shown in Fig. 11 shows an example in which an excitation abnormality occurs in the excitation phase coil 14. When the excitation abnormality occurs in the excitation phase coil 14, it is an undetermined excitation abnormality. When an excitation abnormality occurs in the excitation phase coil 14, a detection abnormality occurs in both the Sin phase coil 16 and the Cos phase coil 18. Therefore, the excitation device 20 sets the excitation state to intermittent excitation and continues excitation. This makes it possible to try to identify the location of the abnormality while suppressing power loss in the amplifier unit 24.

[0062] Then, when the excitation abnormality continues for a second predetermined period while the intermittent excitation is being performed, the excitation device 20 determines that the excitation abnormality has been confirmed. In response to the confirmation of the excitation abnormality, the excitation device 20 switches the excitation state from intermittent excitation to excitation stop.

[0063] 12 illustrates an example in which a detection abnormality occurs due to a disconnection in the Cos phase coil 18. In Case 2, it is assumed that the motor stops at an angular position where the amplitude of the detection signal from the Sin phase coil 16 becomes smaller than the zero fixation threshold at the timing when a detection abnormality occurs due to a disconnection in the Cos phase coil 18. In this case, the excitation is normal, but since a detection abnormality occurs in both the Sin phase coil 16 and the Cos phase coil 18, the excitation device 20 sets the excitation state to intermittent excitation.

[0064] Then, while intermittent excitation is being performed, the motor starts to rotate, which also rotates the rotor 12 of the resolver 10. As a result, the amplitude of the detection signal from the Sin phase coil 16 exceeds the zero-fixation threshold, and the exciter 20 is able to determine that no detection abnormality has occurred in the Sin phase coil 16, and that a detection abnormality has occurred only in the Cos phase coil 18. Then, since a detection abnormality has occurred in only one of the Sin phase coil 16 and the Cos phase coil 18, the exciter 20 changes the excitation state to continuous excitation.

[0065] 13 illustrates an example in which a detection anomaly due to a disconnection occurs in the Cos phase coil 18, but the amplitude of the detection signal from the Sin phase coil 16 maintains a value greater than the zero fixation threshold. In Case 3, excitation is normal, and a detection anomaly occurs in only one of the Sin phase coil 16 and the Cos phase coil 18. Therefore, although a detection anomaly occurs in the Cos phase coil 18, the exciter 20 maintains the excitation state as continuous excitation.

[0066] Second embodiment Next, a second embodiment of the present disclosure will be described.

[0067] In the first embodiment described above, the excitation output pattern generating unit 34 outputs an excitation-on signal or an excitation-off signal to the excitation source signal generating unit 22 to realize excitation in accordance with any one of the excitation states, namely, continuous excitation, intermittent excitation, or excitation stop, determined by the determining unit 32.

[0068] In contrast, in the excitation device 20A according to the present embodiment, as shown in FIG. 14, the excitation output pattern generating unit 34 is configured to output an excitation-on signal or an excitation-off signal to a power switch 36 provided on a line that supplies power to the amplifier 24. When the excitation output pattern generating unit 34 outputs an excitation-on signal, the power switch 36 is turned on to supply power to the amplifier 24. Therefore, the amplifier 24 can generate an excitation signal by amplifying the excitation original signal output from the excitation original signal generating unit 22 and supply the excitation signal to the excitation phase coil 14. On the other hand, when the excitation output pattern generating unit 34 outputs an excitation-off signal, the power switch 36 is turned off to stop the power supply to the amplifier 24. For this reason, the amplifier 24 cannot amplify the excitation original signal output from the excitation original signal generating unit 22, and as a result, the excitation signal is not supplied to the excitation phase coil 14. In this embodiment, the excitation source signal generating unit 22, the amplifier 24, the excitation output pattern generating unit 34, and the power switch 36 function as an excitation signal control unit in the claims and control the excitation signal to be output to the excitation phase coil 14.

[0069] As in the first embodiment, the configuration of the second embodiment can also realize continuous excitation, intermittent excitation, and excitation stop according to the excitation state determined by the determination unit 32. Other configurations and operations of the second embodiment are similar to those of the first embodiment, and therefore will not be described.

[0070] Third embodiment Next, a third embodiment of the present disclosure will be described.

[0071] In the above-described second embodiment, the excitation output pattern generating unit 34 is configured to output an excitation-on signal or an excitation-off signal to the power switch 36 provided on the line that supplies power to the amplifier unit 24.

[0072] In contrast, in the excitation device 20B according to the present embodiment, as shown in Fig. 15, the excitation output pattern generating unit 34 is configured to output an excitation-on signal or an excitation-off signal to an output switch 38 provided on an output line extending from the amplifier 24 to the excitation phase coil 14. When the excitation output pattern generating unit 34 outputs an excitation-on signal, the output switch 38 turns on, enabling the amplifier 24 to output an excitation signal to the excitation phase coil 14. Therefore, the amplifier 24 can supply an excitation signal obtained by amplifying the excitation original signal output from the excitation original signal generating unit 22 to the excitation phase coil 14. On the other hand, when the excitation output pattern generating unit 34 outputs an excitation-off signal, the output switch 38 turns off, disabling the amplifier 24 from outputting the excitation signal to the excitation phase coil 14. In this embodiment, the excitation source signal generating unit 22, the amplifier 24, the excitation output pattern generating unit 34, and the output switch 38 function as an excitation signal control unit in the claims and control the excitation signal to be output to the excitation phase coil 14.

[0073] As in the first embodiment, the configuration of the third embodiment can also realize continuous excitation, intermittent excitation, and excitation stop in accordance with the excitation state determined by the determination unit 32. Other configurations and operations of the third embodiment are similar to those of the first embodiment, and therefore will not be described.

[0074] (Fourth embodiment) Next, a fourth embodiment of the present disclosure will be described.

[0075] In the first embodiment described above, the excitation device 20 is configured to perform functions such as the excitation source signal generation unit 22, the excitation anomaly detection unit 26, the detection anomaly detection unit 28, the determination unit 32, and the excitation output pattern generation unit 34 by at least one processor executing a program stored in a memory.

[0076] In contrast, in the excitation device 20C of this embodiment, at least one of the excitation source signal generating unit 22, the excitation anomaly detection unit 26, the detection anomaly detection unit 28, the determination unit 32, and the excitation output pattern generating unit 34 is configured by a hardware circuit such as a logic circuit or a discrete circuit.

[0077] FIG. 16 shows an example in which, in an excitation device 20C, the excitation source signal generating unit 22, the excitation anomaly detecting unit 26, and the detection anomaly detecting unit 28 are respectively constituted by discrete circuits 22C, 26C, and 28C, and the determination unit 32 and the excitation output pattern generating unit 34 are respectively constituted by logic circuits 32C and 34C.

[0078] With the configuration of the fourth embodiment, similar to the first embodiment, continuous excitation, intermittent excitation, and excitation stop can be realized according to the excitation state determined by the determination unit 32 based on excitation abnormalities and / or detection abnormalities.

[0079] Fifth embodiment Next, a fifth embodiment of the present disclosure will be described.

[0080] In the above-described first to fourth embodiments, the excitation abnormality detection unit 26 detects the excitation signal output from the amplifier unit 24 as a voltage signal, and detects an excitation abnormality based on whether the frequency and amplitude of the detected excitation signal are within or outside of a normal range. Similarly, the detection abnormality detection unit 28 detects the Sin phase detection signal and the Cos phase detection signal of the Sin phase coil 16 and the Cos phase coil 18, respectively, as a voltage signal, and detects a detection abnormality based on whether the amplitudes of the detected Sin phase detection signal and Cos phase detection signal exceed a zero fixation threshold.

[0081] In contrast, in the excitation device 20D of this embodiment, the excitation abnormality detection unit 26D and / or the detection abnormality detection unit 28D are configured to detect at least one of the excitation signal, the Sin phase detection signal, and the Cos phase detection signal as a current signal.

[0082] For example, Fig. 17 shows an example in which the excitation signal, the Sin phase detection signal, and the Cos phase detection signal are all detected as current signals by corresponding current sensors 40, 42, 44. Note that the R / D converter 30 is omitted in Fig. 17.

[0083] In this manner, the excitation anomaly detector 26D and / or the detection anomaly detector 28D may detect at least one of the excitation signal, the Sin phase detection signal, and the Cos phase detection signal as a current signal. In this case, too, the occurrence of an excitation anomaly or a detection anomaly can be detected from the excitation signal, the Sin phase detection signal, and the Cos phase detection signal detected as a current signal.

[0084] Finally, this specification discloses the following technical ideas and combinations thereof. The combinations of the following technical ideas apply not only to the resolver excitation device but also to the resolver excitation method.

[0085] (Technical thought 1) An excitation device for a resolver (10) having an excitation phase coil (14) to which an excitation signal is applied, and a Sin phase coil (16) and a Cos phase coil (18) which output a detection signal, an abnormality detection unit (26, 28) that detects occurrence of at least one of an excitation abnormality in the excitation phase coil, a detection abnormality in the Sin phase coil, and a detection abnormality in the Cos phase coil; a determination unit (32) that determines which excitation state to use, among continuous excitation in which an excitation signal is output continuously, intermittent excitation in which an excitation signal is output intermittently, and excitation stop in which output of the excitation signal is stopped, according to the type of the abnormality detected by the abnormality detection unit; and an excitation signal control unit (22, 24, 34, 36, 38) that controls an excitation signal to be output to the excitation phase coil in accordance with the excitation state determined by the determination unit.

[0086] (Technical thought 2) The determination unit determines to change the excitation state to the intermittent excitation when the abnormality detection unit detects all of the excitation abnormality in the excitation signal, the detection abnormality in the detection signal of the Sin phase coil, and the detection abnormality in the detection signal of the Cos phase coil.

[0087] (Technical Thought 3) The resolver excitation device described in Technical Idea 2, wherein when the abnormality detection unit continuously detects the excitation abnormality in the excitation signal while the intermittent excitation is being performed, the determination unit assumes that the excitation abnormality has been confirmed and decides to change the excitation state to the excitation stop.

[0088] (Technical Thought 4) The determination unit determines to change the excitation state to the intermittent excitation when the abnormality detection unit does not detect the excitation abnormality but detects both the detection abnormality in the detection signal of the Sin phase coil and the detection abnormality in the detection signal of the Cos phase coil.

[0089] (Technical Thought 5) The determination unit determines whether to change the excitation state to the continuous excitation or the excitation stop when, during the intermittent excitation, the abnormality detection unit no longer detects either the detection abnormality in the detection signal of the Sin phase coil or the detection abnormality in the detection signal of the Cos phase coil and only detects the other detection abnormality.

[0090] (Technical Thought 6) The determination unit determines to change the excitation state to the excitation stop when the abnormality detection unit detects an excitation abnormality that confirms an excitation abnormality.

[0091] (Technical Thought 7) The resolver excitation device according to any one of Technical Ideas 1 to 6, wherein the abnormality detection unit detects the excitation abnormality when at least one of the frequency and amplitude of the excitation signal deviates from a normal range.

[0092] (Technical Thought 8) The resolver excitation device described in any one of Technical Ideas 1 to 7, wherein the abnormality detection unit detects the detection abnormality of the detection signal of the Sin phase coil and / or the Cos phase coil when the amplitude of the corresponding detection signal does not exceed a predetermined threshold value.

[0093] (Technical Thought 9) The excitation signal control unit includes a power amplifier circuit (24) that generates and outputs an excitation signal, The resolver excitation device according to any one of Technical Ideas 1 to 8, wherein an on-time ratio in the intermittent excitation is set so that even if a large current due to a ground fault flows through the power amplifier circuit, the power loss due to the on-time is smaller than the allowable power loss of the power amplifier circuit.

[0094] (Technical Thought 10) An excitation device for a resolver described in any one of Technical Ideas 1 to 9, wherein the on time of the intermittent excitation is set to be at least equal to or longer than the time during which the detection signals are induced in the Sin phase coil and the Cos phase coil by the application of an excitation signal to the excitation phase coil.

[0095] (Technical Thought 11) The excitation signal control unit includes a power amplifier circuit (24) that generates and outputs an excitation signal, The excitation signal control unit realizes the intermittent excitation by turning on and off the input of an excitation source signal to the power amplifier circuit, turning on and off the supply of power to the power amplifier circuit, or turning on and off the connection between the power amplifier circuit and the excitation phase. [Explanation of symbols]

[0096] 10: resolver, 12: rotor, 14: excitation phase coil, 16: sine phase coil, 18: cosine phase coil, 20: exciter, 22: excitation source signal generator, 24: amplifier, 26: excitation abnormality detector, 28: detection abnormality detector, 30: R / D converter, 32: determination unit, 34: excitation output pattern generator, 36: power switch, 38: output switch

Claims

1. An excitation device for a resolver (10) having an excitation phase coil (14) to which an excitation signal is applied, and a Sin phase coil (16) and a Cos phase coil (18) which output a detection signal, an abnormality detection unit (26, 28) that detects occurrence of at least one of an excitation abnormality in the excitation phase coil, a detection abnormality in the Sin phase coil, and a detection abnormality in the Cos phase coil; a determination unit (32) that determines which excitation state to use, among continuous excitation in which an excitation signal is output continuously, intermittent excitation in which an excitation signal is output intermittently, and excitation stop in which output of the excitation signal is stopped, according to the type of abnormality detected by the abnormality detection unit; and an excitation signal control unit (22, 24, 34, 36, 38) that controls an excitation signal to be output to the excitation phase coil in accordance with the excitation state determined by the determination unit.

2. 2. The resolver excitation device according to claim 1, wherein the determination unit determines to change the excitation state to the intermittent excitation when the abnormality detection unit detects all of the excitation abnormality in the excitation signal, the detection abnormality in the detection signal of the Sin phase coil, and the detection abnormality in the detection signal of the Cos phase coil.

3. 3. The resolver excitation device according to claim 2, wherein when the excitation abnormality of the excitation signal is continuously detected by the abnormality detection unit while the intermittent excitation is being performed, the determination unit determines that the excitation abnormality has been confirmed and determines to change the excitation state to the excitation stop.

4. 2. The resolver excitation device according to claim 1, wherein the determination unit determines to change the excitation state to the intermittent excitation when the abnormality detection unit does not detect the excitation abnormality but detects both the detection abnormality in the detection signal of the Sin phase coil and the detection abnormality in the detection signal of the Cos phase coil.

5. 5. The resolver excitation device according to claim 4, wherein the determination unit determines to change the excitation state to the continuous excitation or the excitation stop when, during the intermittent excitation, the abnormality detection unit no longer detects either the detection abnormality in the detection signal of the Sin phase coil or the detection abnormality in the detection signal of the Cos phase coil and only detects the other detection abnormality.

6. 6. The resolver excitation device according to claim 1, wherein the determination unit determines to change the excitation state to the excitation stop when the abnormality detection unit detects an abnormality that confirms the excitation abnormality.

7. 6. The resolver excitation device according to claim 1, wherein the abnormality detection unit detects the excitation abnormality when at least one of a frequency and an amplitude of the excitation signal deviates from a normal range.

8. 6. The resolver excitation device according to claim 1, wherein the abnormality detection unit detects the detection abnormality of the detection signal of the Sin phase coil and / or the Cos phase coil when the amplitude of the corresponding detection signal does not exceed a predetermined threshold.

9. The excitation signal control unit includes a power amplifier circuit (24) that generates and outputs an excitation signal, 6. The resolver excitation device according to claim 1, wherein an on-time ratio in the intermittent excitation is set so that a power loss due to an on-time is smaller than an allowable power loss of the power amplifier circuit even if a large current due to a ground fault flows through the power amplifier circuit.

10. 6. The resolver excitation device according to claim 1, wherein an on-time of the intermittent excitation is set to be at least equal to or longer than a time during which the detection signals are induced in the Sin phase coil and the Cos phase coil by energizing an excitation signal to the excitation phase coil.

11. The excitation signal control unit includes a power amplifier circuit (24) that generates and outputs an excitation signal, 6. The resolver excitation device according to claim 1, wherein the excitation signal control unit realizes the intermittent excitation by turning on and off an input of an excitation source signal to the power amplifier circuit, turning on and off a supply of power to the power amplifier circuit, or turning on and off a connection between the power amplifier circuit and the excitation phase coil.

12. An excitation method implemented by an excitation device (20) for exciting a resolver (10) having an excitation phase coil (14) to which an excitation signal is applied, and a Sin phase coil (16) and a Cos phase coil (18) which output a detection signal, comprising: Detecting the occurrence of at least one of an excitation abnormality in the excitation phase coil, a detection abnormality in the Sin phase coil, and a detection abnormality in the Cos phase coil; determining whether the excitation state should be a continuous excitation state in which an excitation signal is continuously output, an intermittent excitation state in which an excitation signal is intermittently output, or an excitation stop state in which output of the excitation signal is stopped, according to the type of the detected abnormality; and controlling an excitation signal to be output to the excitation phase coil in accordance with the determined excitation state.

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