Excitation device and excitation method for resolver

Abstract

A determination unit (32) determines which excitation state to choose from among continuous excitation in which an excitation signal is continuously output, intermittent excitation in which the excitation signal is intermittently output, and excitation stop in which the output of the excitation signal is stopped, in accordance with a mode of abnormality detected by an excitation abnormality detection unit (26) or a detection abnormality detection unit (28). This makes it possible to perform, when at least one of excitation abnormality of an excitation phase coil (14), detection abnormality of a Sin phase coil (16), and detection abnormality of a Cos phase coil (18) occurs, excitation of a resolver (10) in an excitation state suitable for the mode of abnormality that has occurred.

Description

Resolver excitation device and excitation method CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2023-107361 filed in Japan on June 29, 2023, and the contents of the original application are incorporated by reference in their entirety.

[0002] The present disclosure relates to an excitation device and an excitation method for a resolver having an excitation phase coil to which an excitation signal is applied, and a sine phase coil and a cosine phase coil that output a detection signal.

[0003] 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.

[0004] Patent No. 5763420

[0005] In the resolver drive device of Patent Document 1, when the vehicle is stopped and there is little need for angle detection, 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 excitation abnormalities or detection abnormalities that occur in the resolver.

[0006] For example, if an excitation abnormality occurs due to a ground fault in the wiring connected to the excitation phase, and excitation continues in the constant excitation mode, a large current will flow 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 sine phase or cosine phase, the angle cannot be detected, but the excessive power loss described above will not occur. Therefore, even if excitation is performed in the constant excitation mode, this does not pose a major problem.

[0007] The present disclosure has been made in consideration of the above-mentioned points, and aims to provide a resolver excitation device and excitation method that can appropriately control the excitation state of a resolver depending on the nature of the abnormality when an excitation abnormality or detection abnormality occurs.

[0008] In order to achieve the above object, the resolver excitation device according to the present disclosure is an excitation device for a resolver having an excitation phase coil to which an excitation signal is applied, and a sine phase coil and a cosine phase coil that output a detection signal, and is characterized by comprising: an abnormality detection unit that detects the occurrence of at least one of an excitation abnormality in the excitation phase coil, a detection abnormality in the sine phase coil, and a detection abnormality in the cosine phase coil; a determination unit that determines which excitation state to use, from continuous excitation that continuously outputs an excitation signal, intermittent excitation that intermittently outputs an excitation signal, or excitation stop that stops output of the excitation signal, depending on the type of abnormality detected by the abnormality detection unit; and an excitation signal control unit that controls the excitation signal to be output to the excitation phase coil in accordance with the excitation state determined by the determination unit.

[0009] Furthermore, a resolver excitation method according to the present disclosure is an excitation method implemented by an excitation device that excites 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 is characterized by 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, according to the type of the detected abnormality, which excitation state to use: 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 the excitation signal is stopped; and controlling the excitation signal to be output to the excitation phase coil according to the determined excitation state.

[0010] As described above, in the resolver excitation device and excitation method disclosed herein, the excitation state to be used is determined according to the type of abnormality detected: 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. 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 appropriate for the type of abnormality that has occurred.

[0011] The reference numbers in the claims merely indicate an example of a correspondence with specific configurations in the embodiments 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.

[0012] Furthermore, the technical features of the present disclosure other than those described above will become apparent from the following description of the embodiments and the accompanying drawings.

[0013] 1 is a configuration diagram schematically showing the configuration of an excitation device of a resolver according to a first embodiment; FIG. 2 is a waveform diagram showing normal sine phase detection signals and cosine phase detection signals; FIG. 3 is a waveform diagram showing abnormal sine phase detection signals and cosine phase detection signals; FIG. 4 is a waveform diagram showing normal sine phase detection signals and abnormal cosine phase detection signals; FIG. 5 is a diagram showing an example of a judgment table used by a determination unit when determining an excitation state; FIG. 6 is a waveform diagram showing an excitation output pattern and an output waveform to an excitation phase coil when continuous excitation is performed; FIG. 7 is a waveform diagram showing an excitation output pattern and an output waveform to an excitation phase coil when excitation is stopped; FIG. 8 is a waveform diagram showing an excitation output pattern and an output waveform to an excitation phase coil when intermittent excitation is performed; FIG. 9 is a diagram for explaining an excitation-on period and an excitation-off period in intermittent excitation; FIG. 10 is a flowchart showing processing executed to determine an excitation state by an excitation device; FIG. 11 is a diagram showing a first control example related to determination of an excitation state by an excitation device; FIG. 12 is a diagram showing a second control example related to determination of an excitation state by an excitation device; and FIG. 13 is a diagram showing a third control example related to determination of an excitation state by an excitation device. Fig. 1 is a configuration diagram that schematically shows the configuration of a resolver excitation device according to a second embodiment; Fig. 2 is a configuration diagram that schematically shows the configuration of a resolver excitation device according to a third embodiment; Fig. 3 is a configuration diagram that schematically shows the configuration of a resolver excitation device according to a fourth embodiment; Fig. 4 is a configuration diagram that schematically shows the configuration of a resolver excitation device according to a fifth embodiment;

[0014] Preferred embodiments of the present disclosure will be described below with reference to the drawings. Note that identical or similar configurations may be omitted from description by assigning the same reference numerals across multiple drawings. When only a portion of a configuration is described in each embodiment, the configuration of another previously described embodiment may be applied to the remaining portions of the configuration. Furthermore, configurations of multiple embodiments may be partially combined, even if not explicitly described, as long as there is no particular problem with the combination.

[0015] First Embodiment FIG. 1 is a diagram schematically illustrating the configuration of an excitation device 20 of a resolver 10 according to a first embodiment.

[0016] The resolver 10 is a sensor that detects the rotation angle of a motor (not shown). A 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 sine phase coil 16 and a cosine phase coil 18. The excitation phase coil 14 may be provided on the rotor 12 of the resolver 10, or 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.

[0017] 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, 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. As the rotor 12 rotates, the flux linkage of the sine-phase coil 16 and the cos-phase coil 18 due to the magnetic flux from the excitation phase coil 14 changes periodically. As a result, sine-wave sine-phase detection signals and cos-phase detection signals are induced in the sine-phase coil 16 and the cos-phase coil 18 as the rotor 12 rotates.

[0018] The sine-phase coil 16 and the cosine-phase coil 18 are arranged such that the phases of the sine-phase detection signals and the cosine-phase detection signals generated by the sine-phase coil 16 and the cosine-phase coil 18 are shifted by π / 2. Therefore, if the excitation signal of the excitation phase coil 14 is "sinωt," the sine-phase detection signal and the cosine-phase detection signal detected by the sine-phase coil 16 and the cosine-phase coil 18 are "sinθ×sinωt" and "cosθ×sinωt," respectively. θ represents the angle of the rotor 12. The rotation angle of the motor can be calculated based on the sine-phase detection signal and the cosine-phase detection signal of the sine-phase coil 16 and the cosine-phase coil 18. The rotor 12 may be configured to have multiple convex shapes formed on its outer periphery, thereby generating multiple cycles of frequency fluctuation per rotation of the rotor 12.

[0019] 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 from the sine phase coil 16 and the cosine phase coil 18. The excitation device 20 detects the occurrence of at least one of an excitation abnormality in 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 depending on the type of the detected abnormality: continuous excitation, which continuously outputs an excitation signal; intermittent excitation, which intermittently outputs an excitation signal; or excitation stop, which stops output of the excitation signal. The excitation device 20 then controls the excitation signal to be output to the excitation phase coil 14 of the resolver 10 in accordance with the determined excitation state. In this way, when at least one of an excitation abnormality in the excitation phase coil 14, a detection abnormality in the Sin phase coil 16, and a 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 type of abnormality that has occurred.

[0020] In order to perform the above-described functions, the excitation device 20 includes an excitation source signal generating unit 22, an amplifier unit 24, an excitation anomaly detecting unit 26, a detection anomaly detecting unit 28, an R / D converter 30, a determination unit 32, and an excitation output pattern generating unit 34. The excitation device 20 can be configured by a known computer including 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 unit 22, the excitation anomaly detecting unit 26, the detection anomaly detecting unit 28, the determination unit 32, and the excitation output pattern generating unit 34 by having the at least one processor execute a program stored in the memory.

[0021] The excitation source signal generating unit 22 generates and outputs an excitation source 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 source signal generating unit 22 stops outputting the excitation source signal during an excitation-off period when excitation-off is instructed by the excitation output pattern generating unit 34.

[0022] 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 be applied to 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.

[0023] 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 receives the excitation signal output from the amplifier unit 24 and can detect the excitation abnormality based on whether the frequency of the excitation signal (sine wave signal) is within the frequency range of a normal excitation signal and / or whether 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.

[0024] The above 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.

[0025] The detection abnormality detector 28 detects detection abnormalities in the sine phase coil 16 and the cos phase coil 18. The detection abnormality detector 28 receives the sine phase detection signal and the cos phase detection signal from the sine phase coil 16 and the cos phase coil 18, respectively. The detection abnormality detector 28 can detect detection abnormalities based on, for example, whether the amplitudes of the sine phase detection signal and the cos phase detection signal exceed a predetermined threshold (fixed-zero threshold). However, the detection abnormality detector 28 may also detect detection abnormalities other than the fixed-zero state, such as when the sine phase detection signal and / or the cos phase detection signal is stuck at a value exceeding the fixed-zero threshold due to a power fault.

[0026] As an example, as shown in FIG. 2 , the detection abnormality detection unit 28 determines that a detection abnormality has not occurred and that the detection is normal when the peak values ​​of the Sin phase detection signal and the Cos phase detection signal from the Sin phase coil 16 and the Cos phase coil 18, respectively, periodically change and exceed the zero-stick threshold. If the detection abnormality detection unit 28 determines that the detection is normal, it may notify the determination unit 32 that the detection is normal. On the other hand, as shown in FIG. 3 , the detection abnormality detection unit 28 determines that a detection abnormality has occurred when the peak values ​​of the Sin phase detection signal and the Cos phase detection signal from the Sin phase coil 16 and the Cos phase coil 18, respectively, do not exceed the zero-stick threshold, or when the peak value of one of the detection signals from the Sin phase coil 16 and the Cos phase coil 18 exceeds the zero-stick threshold but the peak value of the other detection signal does not exceed the zero-stick threshold. When the detected abnormality detector 28 detects a detected abnormality, it notifies the determination unit 32 of the detection result of the detected abnormality together with information indicating the state of the detected abnormality.

[0027] 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 value can occur when the Sin phase coil 16 and / or Cos phase coil 18 is broken, when the Sin phase coil 16 and / or Cos phase coil 18 is 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 sin phase detection signal and the cos phase detection signal of the sin phase coil 16 and the cos phase coil 18 do not exceed the zero sticking threshold can actually occur when the sin phase coil 16 and the cos phase coil 18 suffer from a break, a ground fault, a mutual short circuit, or a short circuit between their output lines. However, it can also occur when one of the sin phase coil 16 and the cos phase coil 18 suffers from a break or a ground fault and the rotor 12 stops at an angular position where the peak value of the other detection signal is below the zero sticking threshold.

[0028] 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 cosine-phase detection signals of the sine-phase coil 16 and the cosine-phase coil 18, respectively. For example, the R / D converter 30 receives the detection signals of the sine-phase coil 16 and the cosine-phase coil 18 and converts each detection signal into a digital signal using an A / D converter (not shown) to identify its 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 cosine-phase detection signal. The A / D converter may be built into the R / D converter 30 or provided externally.

[0029] The determination unit 32 determines 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 determination 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.

[0030] The processing in the determination unit 32 will be described in detail below. The determination unit 32 first 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.

[0031] Regarding the type of 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 assume that a failure has occurred in the excitation source signal generation unit 22 and / or the amplifier unit 24, or that a short circuit to power has occurred in the excitation phase coil 14, and can determine that an excitation abnormality has been confirmed as the type of excitation abnormality. However, the determination unit 32 may also determine that an excitation abnormality has been confirmed if the notification of the abnormality described above continues for a first predetermined time.

[0032] Furthermore, when the determination unit 32 is notified by the excitation anomaly detection unit 26 of an anomaly 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 anomaly 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 anomaly is an unconfirmed excitation anomaly. In other words, when the deviation of the frequency or amplitude from the normal range is not so large as to be clearly regarded as an anomaly, the determination unit 32 determines that there is a possibility of an excitation anomaly, but that it has not yet been confirmed.

[0033] In this way, the excitation abnormality determined by the determination unit 32 can be classified into a confirmed excitation abnormality and an unconfirmed excitation abnormality.

[0034] Regarding the type of detection abnormality, for example, if the detection abnormality detector 28 notifies the determination unit 32 of detection abnormalities in the Sin-phase coil 16 and the Cos-phase coil 18 at the same time, the determination unit 32 determines that the type of detection abnormality is detection abnormalities 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, causing the rotor 12 to stop at an angular position where the detection signal of the other coil is equal to or lower than the zero-fixing threshold.

[0035] In addition, for example, when the determination unit 32 is notified by the detection abnormality detection unit 28 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.

[0036] In this way, the detection abnormality determined by the determination unit 32 can be a detection abnormality in both the sine phase coil 16 and the cos phase coil 18, or a detection abnormality in either the sine phase coil 16 or the cos phase coil 18.

[0037] The determination unit 32 then comprehensively determines the type of abnormality related to excitation and detection of the resolver 10 based on the determined type of excitation abnormality and the type of detection abnormality. The determination unit 32 then determines whether the excitation state of the excitation phase coil 14 should be continuous excitation, intermittent excitation, or excitation stop, depending on the determination result of the overall type of abnormality related to 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.

[0038] 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 determines that no abnormality has occurred and that the excitation state of the excitation phase coil 14 is to be continuous excitation.

[0039] On the other hand, if 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.

[0040] Furthermore, if excitation is normal or an undetermined excitation abnormality has occurred and a detection abnormality has occurred in either the sine-phase coil 16 or the cosine-phase coil 18, the decision unit 32 determines that the abnormality in the excitation and detection of the resolver 10 is such that continuous excitation will not result in significant power loss, and decides to change the excitation state to continuous excitation. In this case, because normal detection is being performed in either the sine-phase coil 16 or the cosine-phase coil 18, even if an undetermined excitation abnormality has occurred, it can be considered that this is temporary or minor and that no definite excitation abnormality has occurred. Therefore, even if continuous excitation of the excitation phase coil 14 is performed, it is unlikely that excessive power loss will occur in the amplifier unit 24 or the like.

[0041] 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 stop the excitation state. Also, if a detection abnormality occurs in either the sine-phase coil 16 or the cosine-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 stop the excitation state instead of continuing the excitation state.

[0042] On the other hand, if the excitation is normal or an undetermined excitation abnormality has occurred and detection abnormalities have occurred in both the Sin phase coil 16 and the Cos phase coil 18, the decision unit 32 decides to change the excitation state to intermittent excitation.

[0043] In particular, when an undetermined excitation abnormality occurs in which the amplitude of the excitation signal is smaller than the normal range, and a detection abnormality occurs in both the Sin-phase coil 16 and the Cos-phase coil 18, where the amplitude is below the zero fixation threshold, it is impossible to determine whether an abnormality such as a wire break or ground fault has occurred in the excitation phase coil 14, causing the detection abnormality in both the Sin-phase coil 16 and the Cos-phase coil 18, or whether the excitation abnormality is temporary and an abnormality actually exists in both the Sin-phase coil 16 and the Cos-phase coil 18. Therefore, in order to identify the location of the abnormality, it is necessary to continue exciting the excitation phase coil 14.

[0044] However, if continuous excitation is performed when a ground fault has occurred in the wiring connected to the excitation phase coil 14, the resistance caused by the excitation phase coil 14 will disappear, causing a large current to flow through the amplifier unit 24, which may result in excessive power loss.

[0045] In contrast, when the determination unit 32 determines that the excitation state is to be intermittent excitation, it becomes possible to suppress power loss in the amplifier unit 24 and the like, compared to continuous excitation. Furthermore, there is no need to design the amplifier unit 24 with a margin to withstand excessive power loss, which makes it possible to reduce the cost and size of the amplifier unit 24.

[0046] In addition, when an undetermined excitation abnormality occurs, in which the amplitude of the excitation signal is reduced, and detection abnormalities are detected in both the Sin-phase coil 16 and the Cos-phase coil 18, intermittent excitation is performed, and if it is determined that there is an abnormality in the excitation by the excitation phase coil 14, the decision unit 32 can decide to stop the excitation state. Furthermore, when it is determined that the excitation is normal but there is a detection abnormality in either the Sin-phase coil 16 or the Cos-phase coil 18 due to intermittent excitation, the decision unit 32 can decide to change the excitation state to continuous excitation or stop excitation. Similarly, when it is determined that the excitation is normal but there are detection abnormalities in both the Sin-phase coil 16 and the Cos-phase coil 18 due to intermittent excitation, the decision unit 32 may maintain the excitation state as intermittent excitation, or may change the excitation state to continuous excitation or stop excitation.

[0047] 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 was 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.

[0048] Note that if the excitation is normal, there is no risk of excessive power loss even if continuous excitation is performed. Therefore, even if the excitation is normal and detection abnormalities have occurred in both the sine-phase coil 16 and the cosine-phase coil 18, the determination unit 32 may determine that the excitation state should be continuous excitation.

[0049] The excitation output pattern generation unit 34 selects and outputs either an excitation-on signal that instructs excitation-on or an excitation-off signal that instructs excitation-off to the excitation source signal generation unit 22 so that an excitation signal is output from the amplification unit 24 in accordance with the excitation state determined by the determination unit 32. Specifically, when the determination unit 32 determines that the excitation state is continuous excitation, the excitation output pattern generation unit 34 continuously outputs the excitation-on signal to the excitation source signal generation unit 22, as shown in FIG. 6(b). During the excitation-on period in which the excitation-on signal is being output, the excitation source signal generation unit 22 continuously outputs an excitation source signal having a sinusoidal waveform. As a result, the amplification unit 24 continuously outputs the excitation signal to the excitation phase coil 14, as shown in FIG. 6(a), thereby realizing an excitation state in accordance with continuous excitation.

[0050] Furthermore, when the determination unit 32 determines that the excitation state should be changed to excitation stop, 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 in accordance with excitation stop.

[0051] Furthermore, when the determination unit 32 determines that the excitation state should 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 Figure 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 the excitation signal to the excitation phase coil 14 only during the excitation-on period Ton and stops outputting the excitation signal during the excitation-off period Toff, as shown in Figure 8(a), thereby achieving an excitation state in accordance with intermittent excitation.

[0052] The excitation-on period Ton in intermittent excitation is set to a time that is 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 sine phase detection signal and a cosine phase detection signal are induced in the sine phase coil 16 and the cosine phase coil 18, respectively, by the application of an excitation signal to the excitation phase coil 14. By setting the excitation-on period Ton to a time that is longer than the excitation start-up time, it is possible to verify the authenticity of detection abnormalities in the sine phase coil 16 and the cosine phase coil 18 based on the sine phase detection signal and the cos phase detection signal while intermittent excitation is being performed.

[0053] 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 the sine phase detection signal and the cosine phase detection signal are input to the R / D converter 30 until the R / D converter 30 calculates and outputs the angle corresponding to the input sine phase detection signal and the cosine phase detection signal.

[0054] When the exciter 20 starts energizing the excitation phase coils 14 of the resolver 10 and starts detecting the rotation angle of the motor using the resolver 10, the exciter 20 executes a startup sequence to detect the angle after the above-mentioned excitation startup 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 startup time and the R / D converter settling time, the exciter 20 can use the normal startup sequence as is even during the excitation-on period in intermittent excitation.

[0055] Furthermore, it is preferable that the excitation-on period ratio (Ton / (Ton+Toff)) in intermittent excitation be 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 ensures that the amplifier unit 24 is protected even if a large current flows.

[0056] Next, referring to the flowchart of Figure 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 to use: continuous excitation, intermittent excitation, or excitation stop, depending on the nature of the detected abnormality.

[0057] In step S100, the excitation device 20 determines whether 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 this 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.

[0058] In step S110, since an 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 generation unit 34.

[0059] 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 if 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.

[0060] In step S130, since detection abnormalities have been detected in both the sine-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 sine-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.

[0061] Next, some examples of control by the excitation device 20 will be described with reference to FIGS.

[0062] Case 1 shown in Figure 11 illustrates an example in which an excitation abnormality occurs in the excitation phase coil 14. When an 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 sine phase coil 16 and the cosine phase coil 18. Therefore, the excitation device 20 continues excitation by setting the excitation state to intermittent excitation. This makes it possible to attempt to identify the location of the abnormality while suppressing power loss in the amplifier unit 24.

[0063] Then, when the excitation abnormality continues for a second predetermined period while intermittent excitation is being performed, the excitation device 20 determines that the excitation abnormality has been confirmed. In response to this confirmation of the excitation abnormality, the excitation device 20 switches the excitation state from intermittent excitation to excitation stop.

[0064] Case 2 shown in Figure 12 illustrates an example in which a detection abnormality due to a wire break occurs 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-fixing threshold at the timing when the detection abnormality due to a wire break occurs in the Cos-phase coil 18. In this case, excitation is normal, but because detection abnormalities occur in both the Sin-phase coil 16 and the Cos-phase coil 18, the excitation device 20 switches the excitation state to intermittent excitation.

[0065] Then, while intermittent excitation is being performed, the motor begins to rotate, which in turn causes the rotor 12 of the resolver 10 to rotate. As a result, the amplitude of the detection signal from the sine-phase coil 16 exceeds the zero-sticking threshold, allowing the exciter 20 to determine that no detection abnormality has occurred in the sine-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 sine-phase coil 16 and the cos-phase coil 18, the exciter 20 changes the excitation state to continuous excitation.

[0066] 13 illustrates an example in which a detection abnormality due to a wire break occurs in the Cos-phase coil 18, but the amplitude of the detection signal from the Sin-phase coil 16 remains greater than the zero-fixing threshold. In Case 3, excitation is normal, and a detection abnormality occurs in only one of the Sin-phase coil 16 and the Cos-phase coil 18. Therefore, although a detection abnormality occurs in the Cos-phase coil 18, the excitation device 20 maintains the excitation state as continuous excitation.

[0067] Second Embodiment Next, a second embodiment of the present disclosure will be described.

[0068] In the first embodiment described above, the excitation output pattern generation unit 34 outputs an excitation-on signal or an excitation-off signal to the excitation source signal generation unit 22, thereby realizing excitation in accordance with the excitation state determined by the determination unit 32, namely, continuous excitation, intermittent excitation, or excitation stop.

[0069] 14 , in the excitation device 20A according to this embodiment, the excitation output pattern generation unit 34 is configured to output an excitation-on signal or an excitation-off signal to a power switch 36 provided on a line supplying power to the amplifier unit 24. When the excitation output pattern generation unit 34 outputs an excitation-on signal, the power switch 36 turns on and supplies power to the amplifier unit 24. Therefore, the amplifier unit 24 can generate an excitation signal by amplifying the excitation source signal output from the excitation source signal generation unit 22 and supply the excitation signal to the excitation phase coil 14. On the other hand, when the excitation output pattern generation unit 34 outputs an excitation-off signal, the power switch 36 turns off and stops the supply of power to the amplifier unit 24. Therefore, the amplifier unit 24 cannot amplify the excitation source signal output from the excitation source signal generation 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 generator 22, amplifier 24, excitation output pattern generator 34, and power switch 36 function as an excitation signal controller in the claims and control the excitation signal to be output to the excitation phase coil 14.

[0070] As with the first embodiment, the configuration of the second embodiment also makes it possible to realize continuous excitation, intermittent excitation, and excitation stop in accordance with the excitation state determined by the determination unit 32. Note that other configurations and operations of the second embodiment are similar to those of the first embodiment, and therefore will not be described here.

[0071] Third Embodiment Next, a third embodiment of the present disclosure will be described.

[0072] In the second embodiment described above, 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 .

[0073] 15 , in the excitation device 20B according to this embodiment, the excitation output pattern generation 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 unit 24 to the excitation phase coil 14. When the excitation output pattern generation unit 34 outputs an excitation-on signal, the output switch 38 turns on, enabling the amplifier unit 24 to output an excitation signal to the excitation phase coil 14. Therefore, the amplifier unit 24 can supply an excitation signal obtained by amplifying the excitation original signal output from the excitation original signal generation unit 22 to the excitation phase coil 14. On the other hand, when the excitation output pattern generation unit 34 outputs an excitation-off signal, the output switch 38 turns off, disabling the amplifier unit 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.

[0074] As with the first embodiment, the configuration of the third embodiment also makes it possible to realize continuous excitation, intermittent excitation, and excitation stop in accordance with the excitation state determined by the determination unit 32. Note that other configurations and operations of the third embodiment are the same as those of the first embodiment, and therefore will not be described here.

[0075] Fourth Embodiment Next, a fourth embodiment of the present disclosure will be described.

[0076] 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 abnormality detection unit 26, the detection abnormality detection unit 28, the determination unit 32, and the excitation output pattern generation unit 34 by having at least one processor execute a program stored in memory.

[0077] In contrast, in the excitation device 20C of this embodiment, at least one of the excitation source signal generation unit 22, excitation abnormality detection unit 26, detection abnormality detection unit 28, determination unit 32, and excitation output pattern generation unit 34 is configured by a hardware circuit such as a logic circuit or a discrete circuit.

[0078] Figure 16 shows an example in which, in an excitation device 20C, the excitation source signal generation unit 22, the excitation abnormality detection unit 26, and the detection abnormality detection unit 28 are respectively composed of discrete circuits 22C, 26C, and 28C, and the determination unit 32 and the excitation output pattern generation unit 34 are respectively composed of logic circuits 32C and 34C.

[0079] With the configuration of the fourth embodiment, similar to the first embodiment, continuous excitation, intermittent excitation, and excitation stop can be achieved according to the excitation state determined by the determination unit 32 based on excitation abnormalities and / or detection abnormalities.

[0080] Fifth Embodiment Next, a fifth embodiment of the present disclosure will be described.

[0081] In the first to fourth embodiments described above, 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 sine phase detection signal and the cosine phase detection signal of the sine phase coil 16 and the cosine phase coil 18 as voltage signals, and detects a detection abnormality based on whether the amplitudes of the detected sine phase detection signal and cos phase detection signal exceed a zero fixation threshold.

[0082] 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.

[0083] For example, Fig. 17 shows an example in which the excitation signal, the sine phase detection signal, and the cosine phase detection signal are all detected as current signals by corresponding current sensors 40, 42, and 44. Note that the R / D converter 30 is omitted from Fig. 17.

[0084] In this way, the excitation anomaly detector 26D and / or the detection anomaly detector 28D may detect at least one of the excitation signal, the sine phase detection signal, and the cosine phase detection signal as a current signal. In this case, too, it is possible to detect the occurrence of an excitation anomaly or a detection anomaly from the excitation signal, the sine phase detection signal, and the cosine phase detection signal detected as a current signal.

[0085] Finally, this specification discloses the following technical ideas and their combinations. The combinations of the following technical ideas apply not only to the resolver excitation device but also to the resolver excitation method.

[0086] (Technical Idea 1) An excitation device for a resolver (10) having an excitation phase coil (14) to which an excitation signal is applied, and a sine phase coil (16) and a cosine phase coil (18) that output a detection signal, the excitation device comprising: an abnormality detection unit (26, 28) that detects the occurrence of at least one of an excitation abnormality in the excitation phase coil, a detection abnormality in the sine phase coil, and a detection abnormality in the cosine phase coil; a determination unit (32) that determines, depending on the type of abnormality detected by the abnormality detection unit, which excitation state to select: continuous excitation that continuously outputs an excitation signal, intermittent excitation that intermittently outputs an excitation signal, or excitation stop that stops output of the excitation signal; 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.

[0087] (Technical Idea 2) The resolver excitation device described in Technical Idea 1, wherein the decision unit decides to change the excitation state to the intermittent excitation when the abnormality detection unit detects 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.

[0088] (Technical Idea 3) In the resolver excitation device according to Technical Idea 2, when the abnormality detection unit continuously detects the excitation abnormality in the excitation signal while the intermittent excitation is being performed, the decision unit determines that the excitation abnormality has been confirmed and decides to change the excitation state to the excitation stop.

[0089] (Technical Idea 4) The resolver excitation device according to Technical Idea 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.

[0090] (Technical Idea 5) The determination unit determines to change the excitation state to the continuous excitation or the excitation stop when, while the intermittent excitation is being performed, 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 the other detection abnormality is detected.This is an excitation device for a resolver described in Technical Idea 4.

[0091] (Technical Idea 6) The resolver excitation device according to any one of Technical Ideas 1 to 5, wherein the determination unit determines to change the excitation state to excitation stop when the abnormality detection unit detects an excitation abnormality that confirms an excitation abnormality.

[0092] (Technical Idea 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 a frequency and an amplitude of an excitation signal deviates from a normal range.

[0093] (Technical Idea 8) The resolver excitation device described in any one of Technical Ideas 1 to 7, wherein the abnormality detection unit detects the detection abnormality in 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.

[0094] (Technical Idea 9) The excitation device for a resolver according to any one of Technical Ideas 1 to 8, wherein the excitation signal control unit includes a power amplifier circuit (24) that generates and outputs an excitation signal, and an on-time ratio in the intermittent excitation is set so that even if a large current due to a ground fault flows in the power amplifier circuit, the power loss due to the on-time is smaller than the allowable power loss of the power amplifier circuit.

[0095] (Technical Idea 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 energizing an excitation signal to the excitation phase coil.

[0096] (Technical Idea 11) The resolver excitation device according to any one of Technical Ideas 1 to 10, wherein the excitation signal control unit includes a power amplifier circuit (24) that generates and outputs an excitation signal, and 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.

Claims

1. An excitation device for a resolver (10) having an excitation phase coil (14) to which an excitation signal is applied, and a sine phase coil (16) and a cosine phase coil (18) that output a detection signal, the resolver excitation device comprising: an abnormality detection unit (26, 28) that detects the occurrence of at least one of an excitation abnormality in the excitation phase coil, a detection abnormality in the sine phase coil, and a detection abnormality in the cosine phase coil; a determination unit (32) that determines which excitation state to select, depending on the type of abnormality detected by the abnormality detection unit, from continuous excitation that continuously outputs an excitation signal, intermittent excitation that outputs an excitation signal intermittently, or excitation stop that stops output of the excitation signal; 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.

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

3. The resolver excitation device of claim 2, wherein when the abnormality detection unit continuously detects an excitation abnormality in the excitation signal 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. The resolver excitation device of 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. The resolver excitation device of 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. A resolver excitation device as described in any one of claims 1 to 5, 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. A resolver excitation device as claimed in any one of claims 1 to 5, 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.

8. A resolver excitation device as described in any one of claims 1 to 5, wherein the abnormality detection unit detects the detection abnormality in 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.

9. A resolver excitation device as claimed in any one of claims 1 to 5, wherein the excitation signal control unit includes a power amplifier circuit (24) that generates and outputs an excitation signal, and the on-time ratio in the intermittent excitation is set so that the power loss due to the on-time is smaller than the 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. A resolver excitation device as described in any one of claims 1 to 5, 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.

11. The resolver excitation device according to any one of claims 1 to 5, wherein the excitation signal control unit includes a power amplifier circuit (24) that generates and outputs an excitation signal, and 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 coil.

12. An excitation method implemented by an excitation device (20) that excites a resolver (10) having an excitation phase coil (14) through which an excitation signal is applied, and a sine phase coil (16) and a cosine phase coil (18) that output a detection signal, the method comprising: detecting the occurrence of at least one of an excitation abnormality in the excitation phase coil, a detection abnormality in the sine phase coil, and a detection abnormality in the cosine phase coil; determining, according to the nature of the detected abnormality, which excitation state to be used: 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; and controlling the excitation signal to be output to the excitation phase coil in accordance with the determined excitation state.

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