U.S. patent application number 14/888462 was filed with the patent office on 2016-03-03 for method for detecting abnormality of resolver, angle detection device, motor, and transportation device.
The applicant listed for this patent is NSK LTD.. Invention is credited to Kei KONDO.
Application Number | 20160061631 14/888462 |
Document ID | / |
Family ID | 51416909 |
Filed Date | 2016-03-03 |
United States Patent
Application |
20160061631 |
Kind Code |
A1 |
KONDO; Kei |
March 3, 2016 |
Method for Detecting Abnormality of Resolver, Angle Detection
Device, Motor, and Transportation Device
Abstract
There are provided a method for detecting an abnormality of a
resolver, an angle detection device, a motor, and a transportation
device, by which the abnormality can be detected promptly without
the necessity of any complicated operations. There is provided a
circuit configured to switch between a sine wave and a direct
current voltage to be supplied, as an excitation signal of a
resolver (2). Then, immediately after the power is turned on, the
direct current voltage is applied to the resolver (2), and the
output voltages of the phases of the resolver (2) are measured when
the direct current voltage is applied. In this situation, the
output voltages of the phases are compared with each other. When
none of them matches each other, it is determined that an
abnormality (short-circuit abnormality, short-circuiting) occurs at
the resolver (2).
Inventors: |
KONDO; Kei; (Kanagawa,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NSK LTD. |
Tokyo |
|
JP |
|
|
Family ID: |
51416909 |
Appl. No.: |
14/888462 |
Filed: |
December 19, 2013 |
PCT Filed: |
December 19, 2013 |
PCT NO: |
PCT/JP2013/007484 |
371 Date: |
November 2, 2015 |
Current U.S.
Class: |
324/207.15 |
Current CPC
Class: |
G01D 5/2073 20130101;
G01D 5/20 20130101; H02P 29/024 20130101; G01D 3/08 20130101; H02P
29/0241 20160201; G01D 18/00 20130101; G01D 3/028 20130101 |
International
Class: |
G01D 5/20 20060101
G01D005/20; G01D 18/00 20060101 G01D018/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 15, 2013 |
JP |
2013-103395 |
Claims
1-6. (canceled)
7. An angle detection device, comprising: a resolver configured to
output rotating positional information of a rotating body, as an
electrical signal; a sine wave generator configured to generate a
sine wave signal; a direct current voltage generator configured to
generate a direct current voltage; an excitation signal supplier
configured to select one of the sine wave signal generated by the
sine wave generator or the direct current voltage generated by the
direct current voltage generator, and to supply the selected one to
the resolver as an excitation signal; a voltage measurement portion
configured to measure output voltages of phases of the resolver;
and an abnormality detector configured to detect an abnormality of
the resolver, by comparing the output voltages of the phases of the
resolver measured by the voltage measurement portion, when the
excitation signal supplier supplies the direct current voltage
generated by the direct current voltage generator, as the
excitation signal.
8. The angle detection device according to claim 7, wherein the
excitation signal supplier is configured to select the direct
current voltage generated by the direct current voltage generator
and to supply the direct current voltage to the resolver, as the
excitation signal, immediately after power is turned on.
9. A motor comprising the angle detection device according to claim
7.
10. A transportation device configured to transport a
transportation target by using the motor according to claim 9.
Description
TECHNICAL FIELD
[0001] The present invention relates to a method for detecting an
abnormality of a resolver configured to detect a rotating position
of a rotating body, an angle detection device having a function of
detecting the abnormality of the resolver, and a motor and a
transportation device each having the angle detection device.
BACKGROUND ART
[0002] In one technology, as a method for detecting an abnormality
of a resolver to be used for detecting a rotating angle of an
electric motor or the like, for example, there is a technique
disclosed in Patent Literature 1. In this technique, in
synchronization with a maximum value or a minimum value of an
excitation signal of the resolver, each resolver output signal is
sampled, and when an offset of the sampled value falls out of a
given range near 0, it is determined that an abnormality occurs at
the resolver.
[0003] In addition, as another method for detecting the abnormality
of the resolver, for example, there is a technique disclosed in
Patent Literature 2. In this technique, different values are set to
the respective voltage transformation ratios between the excitation
coil and the respective three resolver coils, and when three rotor
electrical angles (operation electrical angles) operated from the
three-phase resolver signal indicate different values from one
another, it is determined that a short-circuit abnormality occurs
at the resolver.
CITATION LIST
Patent Literature
PLT 1: JP 2001-343253 A
PLT 2: JP 2013-044679 A
SUMMARY
Technical Problem
[0004] In the technique disclosed in Patent Literature 1, however,
as the abnormality of the resolver is detected by the offset of the
sampling signal, an abnormality cannot be detected unless the
rotating angle reaches 180 degrees of the electrical angle at
maximum. Therefore, until the abnormality detection is performed,
the motor is controlled by using an abnormal signal and an adverse
effect may be given to the motor revolution behavior.
[0005] Besides, in the technique disclosed in Patent Literature 2,
amplitude components are respectively extracted from the
three-phase resolver signal, and the operation electrical angle is
operated in three methods from the extracted amplitude values.
Hence, complicated operations are needed for detection of the
short-circuit abnormality of the resolver.
[0006] Therefore, it is an object of the present disclosure to
provide a method for detecting an abnormality of a resolver, an
angle detection device, a motor, and a transportation device, by
which the abnormality can be detected promptly without the
necessity of any complicated operations.
Solution to Problem
[0007] In order to address the above issues, in one embodiment of
the present disclosure, there is provided a method for detecting an
abnormality of a resolver, the method including: applying a direct
current voltage to the resolver configured to output rotating
positional information of a rotating body, as an electrical signal;
and comparing output voltages of phases of the resolver, when the
direct current voltage is applied to detect the abnormality of the
resolver.
[0008] In this manner, although the resolver is excited by use of a
sine wave in general, the direct current voltage is applied to the
resolver and the resolver signal output as a result is confirmed,
so as to determine whether or not an abnormality occurs at the
resolver. In this manner, by use of the fact that the resolver
output signals when the direct current is applied to the resolver
have all the same potentials in a normal state, the output voltages
of the respective phases of the resolver are compared with each
other to detect an abnormal state. Therefore, no complicated
operation is necessary. Further, the abnormal state can be detected
without rotating a rotor.
[0009] In addition, in the above-described method for detecting the
abnormality of the resolver, when the output voltages of phases of
the resolver do not match each other, it may be determined that the
abnormality occurs at the resolver.
[0010] Accordingly, the abnormal state of the resolver can be
detected with a simple configuration appropriately.
[0011] Further, in another embodiment of the present disclosure,
there is provided an angle detection device, including: a resolver
configured to output rotating positional information of a rotating
body, as an electrical signal; a sine wave generator configured to
generate a sine wave signal; a direct current voltage generator
configured to generate a direct current voltage; an excitation
signal supplier configured to select one of the sine wave signal
generated by the sine wave generator or the direct current voltage
generated by the direct current voltage generator, and to supply
the selected one to the resolver as an excitation signal; a voltage
measurement portion configured to measure output voltages of phases
of the resolver; and an abnormality detector configured to detect
an abnormality of the resolver, by comparing the output voltages of
the phases of the resolver measured by the voltage measurement
portion, when the excitation signal supplier supplies the direct
current voltage generated by the direct current voltage generator,
as the excitation signal.
[0012] In this manner, it is possible to switch between the sine
wave and the direct current voltage to be supplied to the resolver.
Hence, after the direct current voltage is applied and the
abnormality is determined, switching is made to the sine wave so
that the general angle detection can be carried out.
[0013] Moreover, in the above-described angle detection device, the
excitation signal supplier may be configured to select the direct
current voltage generated by the direct current voltage generator
and to supply the direct current voltage to the resolver, as the
excitation signal, immediately after power is turned on.
[0014] In this manner, immediately after the power is turned on,
the direct current voltage is applied to the resolver and the
abnormality is determined. Hence, it is possible to confirm that
the resolver is in a normal state, and then it is possible to
detect the angle. Thus, the reliability of the angle detection can
be improved.
[0015] Furthermore, in yet another embodiment of the present
disclosure, there is provided a motor including the above-described
angle detection device.
[0016] Additionally, in further another embodiment of the present
disclosure, there is provided a transportation device configured to
transport a transportation target by using the above-described
motor.
Advantageous Effects
[0017] According to the present disclosure, the abnormality of the
resolver can be detected promptly without the necessity of the
rotor revolution. In addition, since an abnormal determination is
made possible by a simple comparing operation, it is possible to
achieve an abnormality detection function at a low cost.
BRIEF DESCRIPTION OF DRAWINGS
[0018] FIG. 1 is a schematic configuration view of an angle
detection device in one embodiment of the present disclosure;
[0019] FIG. 2 is a circuit diagram illustrative of a configuration
of the angle detection device;
[0020] FIG. 3 is a flow chart illustrative of a short-circuit
abnormality determination procedure; and
[0021] FIG. 4 is a schematic configuration view illustrative of the
angle detection device in another embodiment of the present
disclosure.
DESCRIPTION OF EMBODIMENTS
[0022] Hereinafter, embodiments of the present disclosure will be
described with reference to the attached drawings.
[0023] FIG. 1 is a schematic configuration view of an angle
detection device, in one embodiment of the present disclosure.
[0024] In the drawing, reference numeral 1 indicates a motor
(rotating body), reference numeral 2 indicates a resolver
configured to detect a rotating position of the motor 1. Herein,
the motor 1 is, for example, a direct drive motor included in a
transportation device, and serves as a drive source configured to
drive a transportation target 10.
[0025] In addition, a servo motor includes the motor 1, a resolver
2, and a drive unit 3, to be described later. It is to be noted
that a mega torque motor can be used as the motor 1.
[0026] The resolver 2 is configured to include a cylindrical
stator, and a rotor configured to hold a rotation shaft and
arranged rotatably in the stator, and to change a reluctance
between the rotor and the stator depending on the location of the
rotor so that one cycle of a fundamental wave component of the
reluctance change indicates one revolution of the rotor. In other
words, the inner diameter center of the rotor is aligned with the
inner diameter center of the stator, the outer diameter center of
the rotor is configured to be eccentric by only a certain eccentric
amount from the inner diameter center thereof to change the
thickness of the rotor. Hence, the reluctance changes depending on
the location of the rotor.
[0027] The resolver 2 is a three-phase resolver configured, when a
since wave shaped excitation signal is given from the outside, to
output a resolver signal of phase A changing depending on the
turning angle of the rotation shaft, a resolver signal of phase B,
which is different in phase by 120 degrees from the resolver signal
of phase A, and a resolver signal of phase C, which is different in
phase by 120 degrees from the resolver signal of phase B.
[0028] The resolver 2 and the drive unit 3 are connected by an
electrical cable 5 through a connector 4. The electrical signal
(resolver signal) output from the resolver 2 is transmitted to the
drive unit 3 through the electrical cable 5.
[0029] The drive unit 3 is configured to have a position detection
function of detecting the rotating position (turning angle) of the
motor 1, and an abnormality detection function of detecting a
short-circuit abnormality between phases of the resolver 2. The
position detection function is a function of acquiring a resolver
signal transmitted from the resolver 2 as rotating positional
information of the motor 1, and detecting a rotating position
(turning angle) of the motor 1 based on the resolver signal. In
addition, the abnormality detection function is a function of
detecting short-circuiting/short-circuit abnormality of the
resolver 2, immediately after the power is turned on.
[0030] This drive unit 3 is configured to include an excitation
signal generation block 11, a short-circuit abnormality detection
signal generation block 12, a change-over switch 13, and a current
amplification circuit 14.
[0031] The excitation signal generation block 11 is configured to
generate a sine wave signal, and then to output the sine wave
signal. In addition, the short-circuit abnormality detection signal
generation block 12 is configured to generate a direct current
voltage as a short-circuit abnormality detection signal, and then
to output the short-circuit abnormality detection signal.
[0032] The change-over switch 13 is configured to switch between
the sine wave signal from the excitation signal generation block 11
and the direct current voltage from the short-circuit abnormality
detection signal generation block 12 in response to a switch signal
S1 from an abnormality determination controller 19 to be described
later, to output to the current amplification circuit 14. Herein,
the change-over switch 13 is configured to select and output the
sine wave signal from the excitation signal generation block 11
when the switch signal S1=0, and to select and output the direct
current voltage from the short-circuit abnormality detection signal
generation block 12 when the switch signal S1=1.
[0033] The current amplification circuit 14 is configured to
amplify the signal output from the change-over switch 13, and to
supply the amplified signal as an excitation signal to the resolver
2 through the electrical cable 5.
[0034] Furthermore, the drive unit 3 is configured to include an
angle detection signal reception block 15, an R/D conversion block
16, and a CPU 17. In addition, the CPU 17 is configured to include
an angle detector 18, an abnormality determination controller 19,
and a short-circuit abnormality determination unit 20.
[0035] The angle detection signal reception block 15 is configured
to receive inputs of the three-phase resolver signal output from
the resolver 2 when the excitation signal is applied. Herein, the
resolver signal is a three-phase analog signal of the phase A, the
phase B, and the phase C, each being different in phase by 120
degrees. The angle detection signal reception block 15 is
configured to convert the three-phase resolver signal that has been
input into a two-phase signal and to output the two-phase signal to
the R/D conversion block 16, and in addition, to detect the voltage
of the three-phase resolver signal that has been input and to
output the detected voltage to the short-circuit abnormality
determination unit 20, to be described later, of the CPU 17.
[0036] In other words, the angle detection signal reception block
15 has a configuration illustrated in FIG. 2. As illustrated in
FIG. 2, the angle detection signal reception block 15 is configured
to include shunt resistances R1, R2, and R3, and to detect voltages
(V.sub.A, V.sub.B, and V.sub.C) of the resolver by using the shunt
resistances R1 to R3. In this situation, the resistance values of
the shunt resistances R1 to R3 are all set to the same values. The
respective phase voltages V.sub.A to V.sub.C are converted into
digital values by A/D converters 21a to 21c, and then are input
into the CPU 17 (the short abnormality determination unit 20).
[0037] Further, after the three-phase resolver signal are converted
to the two-phase resolver signal with a three phase/two phase
converter, the angle detection signal reception block 15 is
configured to input the two-phase resolver signal into the R/D
conversion block (RD converter) 16.
[0038] The R/D conversion block 16 is configured to convert an
output signal from the resolver 2 into a digital angle data, and to
input the digital angle data into the angle detector 18 of the CPU
17, as illustrated in FIG. 1. The angle detector 18 is configured
to acquire the angle data that has been output from the R/D
conversion block 16, and to use the angle data for various kinds of
control (motor control and the like).
[0039] In addition, the abnormality determination controller 19 of
the CPU 17 is configured to output the switch signal S1=0, while a
short-circuit abnormality determination process of determining a
short-circuit abnormality of the resolver 2 is being performed, and
to output the switch signal S1=1 in any other case. In one
embodiment of the present disclosure, the short-circuit abnormality
determination process is configured to be carried out for a certain
period of time after the power is turned on, and the switch signal
S1=1 is output.
[0040] The short-circuit abnormality determination unit 20 of the
CPU 17 is configured to carry out the short-circuit abnormality
determination process based on the respective phase voltages
V.sub.A to V.sub.C output from the angle detection signal reception
block 15, while the abnormality determination controller 19 is
outputting the switch signal S1=1. A short-circuit abnormality
determination result is configured to be output to the outside so
that a given abnormality process should be carried out. For
example, the drive control of the motor 1 can be stopped as an
abnormality process.
[0041] Next, a short-circuit abnormality determination process to
be carried out by the CPU 17 will be described specifically.
[0042] FIG. 3 is a flowchart illustrative of the short-circuit
abnormal determination procedure. The short-circuit abnormality
determination process starts, when the power is turned on.
[0043] Firstly, at step S1, the abnormality determination
controller 19 outputs the switch signal S1=1 to the change-over
switch 13. Accordingly, the change-over switch 13 is in a state
indicated by a broken line of FIG. 2, and the short-circuit
abnormality detection signal (DC voltage) generated by the
short-circuit abnormality detection signal generation block 12 is
applied to the three-phase resolver 2.
[0044] Next, at step S2, the short-circuit abnormality
determination unit 20 acquires the voltages of the resolver output
signals output from the three-phase resolver 2. The voltages of the
resolver output signals to be acquired here are values obtained by
the A/D converters 21a to 21c converting the respective phase
voltages V.sub.A to V.sub.C of the resolver 2 detected by the angle
detection signal reception block 15 into digital values.
[0045] At step S3, it is determined whether or not the respective
phase voltage values acquired at step S2 are all equal. Then, when
it is determined that all values have equal potentials at step S4,
processing goes to step S4, whereas when it is determined that all
values do not have equal potentials at step S4, processing goes to
step S5.
[0046] At step S4, it is determined that the resolver signal is in
a normal state, that is, it is determined that no short-circuit
abnormality or short-circuiting occurs at the resolver 2, a
short-circuit abnormality determination result indicating "normal
state" is output, and then the short-circuit abnormality
determination process ends.
[0047] On the other hand, at step S5, it is determined that the
resolver signal is in a short-circuit state or in an open state, a
short-circuit abnormality determination result indicating "abnormal
state" is output, and then the short-circuit abnormality
determination process ends.
[0048] As described above, after the power is turned on, the DC
voltage is applied to the three-phase resolver 2, as the excitation
signal. The impedance characteristic of the resolver coil is
j.omega.L (.omega.: angular acceleration, L: inductance), and the
angular acceleration of the DC voltage is 0 rad/s.sup.2. Hence,
when the DC voltage is applied, the impedance is 0.OMEGA..
Therefore, when the resolver signal is in a normal state, the
voltages available at the shunt resistances R1 to R3 when the DC
voltage is applied are all equal. On the other hand, when the
resolver signal is in an abnormal state (short-circuit state, open
state), the voltages available at the shunt resistances R1 to R3
when the DC voltage is applied are all different from one
another.
[0049] Thus, the abnormal state of the resolver 2 can be detected
by use of the fact that the voltages made available at the shunt
resistances R1 to R3 when the DC voltage is applied change
depending on whether the resolver signal is in an abnormal state
(short-circuit state, open state) or in a normal state.
[0050] It is to be noted that in FIG. 1, the excitation signal
generation block 11 corresponds to a sine wave generator, the
short-circuit abnormality detection signal generation block 12
corresponds to a direct current voltage generator, the change-over
switch 13 and the current amplification circuit 14 correspond to an
excitation signal supplier, the angle detection signal reception
block 15 corresponds to a voltage measurement portion, and the
short-circuit abnormality determination unit 20 corresponds to an
abnormality detector.
[0051] Thus, in one embodiment of the present disclosure, an
abnormality of the resolver 2 can be determined without the need of
the rotor revolution. Thus, when an abnormality occurs at the
resolver 2, the abnormality can be detected promptly.
[0052] Furthermore, since the DC voltage is applied to the resolver
2 immediately after the power is turned on and an abnormality
determination is made, it is possible to start the general angle
detection after the resolver 2 is confirmed to be in a normal
state. Therefore, it is possible to prevent the motor control with
an abnormality signal.
[0053] Now, as another method of detecting an abnormality of the
resolver, different values are set to the respective voltage
transformation ratios between the excitation coil and the
respective three resolver coils, and when three rotor electrical
angles (operation electrical angles) which have been operated from
the three-phase resolver signal indicate different values from one
another, it is determined that the short-circuit abnormality occurs
at the resolver.
[0054] In contrast, in one embodiment of the present disclosure,
all the voltage transformation ratios of the resolver 2 that are
same can be realized. In addition, as an abnormality of the
resolver 2 can be detected in a simple comparing operation, such a
method is achievable at a low cost.
[0055] It is to be noted that in one embodiment of the present
disclosure as described above, by comparing the respective phase
voltages V.sub.A to V.sub.C of the resolver 2 with digital values
converted by the A/D converters 21a to 21c, respectively,
determination of the short-circuit abnormality has been described.
However, the short-circuit abnormality can be determined by use of
a comparator.
[0056] Further, in one embodiment of the present disclosure as
described above, the case where the resolver configured to output
the resolver signals of the phase A, the phase B, and the phase C
is applied has been described. However, a resolver configured to
output the resolver signal of four or more phases is also
applicable.
[0057] Furthermore, in one embodiment of the present disclosure as
described above, as illustrated in FIG. 4, a servomotor can be
configured with the motor 1, the resolver 2, an RD unit 6, and the
drive unit 7. In this case, the RD unit 6 and the drive unit 7,
which are assembled with the resolver 2, are configured to be
connected with the electrical cable 5 through the connector 4.
[0058] The RD unit 6 is configured to have functions of the
above-described angle detection signal reception block 15 and the
R/D conversion block 16. The drive unit 7 is configured to have
functions of the excitation signal generation block 11, the
short-circuit abnormality detection signal generation block 12, the
change-over switch 13, the current amplification circuit 14, and
the CPU 17. Then, the signal output from the RD unit 6 is
transmitted to the drive unit 7 through the electrical cable 5, so
that the angle detection of the resolver 2 and the short-circuit
abnormality determination can be carried out.
INDUSTRIAL AVAILABILITY
[0059] According to the method of detecting an abnormality of the
resolver in the present disclosure, the abnormality of the resolver
can be detected promptly without the need of the rotor revolution.
In addition, as an abnormality determination is made possible by a
simple comparing operation, the abnormality detection function can
be realized at a low cost and it is useful.
REFERENCE SIGNS LIST
[0060] 1 . . . motor (rotating body), 2 . . . resolver, 3 . . .
drive unit, 4 . . . connector, 5 . . . electrical cable, 11 . . .
excitation signal generation block, 12 . . . short-circuit
abnormality detection signal generation block, 13 . . . change-over
switch, 14 . . . current amplification circuit, 15 . . . angle
detection signal reception block, 16 . . . R/D conversion block, 17
. . . CPU, 18 . . . angle detector, 19 . . . abnormality
determination controller, 20 . . . short-circuit abnormality
determination unit, 21a-21c . . . A/D converter
* * * * *