JP2024032142A - Monitoring device, angle detection device, and monitoring method - Google Patents

Abstract

To monitor and correct a change in detection accuracy due to the imbalance between N-th phases.SOLUTION: A monitoring device comprises: a monitoring unit that monitors the detection accuracy in a resolver in the N-th phase (N is an integer of 3 or more) with the square sum of sin signals and cos signals obtained through N-th phase to two phase conversion from the N-th phase output signals in the resolver; and an adjustment unit that adjusts the balance between the output signals according to the detection accuracy obtained through the monitoring.SELECTED DRAWING: Figure 1

Description

The present invention relates to a monitoring device, an angle detection device, and a monitoring method.

2. Description of the Related Art An angle detection device that detects the rotation angle of a motor or the like using a resolver is conventionally known. It is also known that an angle detection device using a resolver has a function of monitoring temperature changes and the like.
For example, in Patent Document 1, in an angular position detection device using a resolver, the modulation component of the N-phase resolver signal is canceled out by analog addition of the N-phase resolver signal for the purpose of improving detection accuracy by compensating for temperature drift. , a technique has been proposed to generate a temperature detection signal that reflects the temperature of the coil.

Japanese Patent Application Publication No. 2005-91269

The technique of Patent Document 1 can monitor and compensate for changes in detection accuracy due to temperature drift, but it is possible to monitor and compensate for changes in detection accuracy due to imbalance between N phases and correct the imbalance. I can't.
Therefore, an object of the present invention is to monitor and correct changes in detection accuracy due to imbalance between N phases.

In order to solve the above problems, one aspect of the monitoring device according to the present invention provides a sine signal obtained by N-phase to two-phase conversion from an N-phase output signal in an N-phase (N is an integer of 3 or more) resolver. and a monitoring unit that monitors the detection accuracy in the resolver based on the sum of squares of the and cosine signals, and an adjustment unit that adjusts the balance of the output signal according to the detection accuracy obtained by monitoring.

According to such a monitoring device, it is possible to accurately monitor detection accuracy and correct imbalance using the sum of squares of the sine signal and the cosine signal.
Further, in the above-mentioned monitoring device, it is preferable that the adjustment section adjusts the output signal of a phase that is unbalanced with respect to other phases among the N phases. By adjusting the output signal of the unbalanced phase, the unbalance between the phases can be easily corrected.

Further, in the above monitoring device, it is preferable that the adjustment section adjusts the output signal by an adjustment amount according to a difference between a local maximum value and a local minimum value in the sum of squares. The difference between the local maximum value and the local minimum value in the sum of squares is an index that accurately indicates the unbalance between the phases, so the unbalance can be accurately corrected by the adjustment amount according to the difference.

Further, in the above monitoring device, the monitoring unit may be arranged to set a first electrical angle of (360°÷N)×M+90° and a first electrical angle of (360 The value E of the sum of squares is monitored at least at one of the second electrical angles of °÷N)×M−90°, and if the value E increases at the first electrical angle and the value E increases at the second electrical angle. If the value E decreases, it is determined that the DC component has increased in the phase with the phase number M. If the value E decreases at the first electrical angle, and if the value E increases at the second electrical angle, the phase number M It is preferable to determine that the DC component has decreased in this phase. With such a determination method, an unbalanced phase can be easily and accurately identified.

In order to solve the above problems, one aspect of the angle detection device according to the present invention includes an N-phase (N is an integer of 3 or more) resolver and an angle for obtaining an electrical angle θ of the resolver from an output signal of the resolver. a detection unit; a monitoring unit that monitors the detection accuracy in the resolver based on the sum of squares of a sine signal and a cosine signal obtained from the N-phase output signal of the resolver by N-phase to two-phase conversion; An adjustment section that adjusts the balance of the output signal according to detection accuracy.
According to such an angle detection device, it is possible to monitor changes in detection accuracy due to unbalance between the N phases and correct the unbalance, thereby enabling highly accurate angle detection.

In order to solve the above problems, one aspect of the monitoring method in the monitoring device according to the present invention is to obtain the output signal from the N-phase output signal of the N-phase (N is an integer of 3 or more) resolver by N-phase to 2-phase conversion. The present invention includes a monitoring step of monitoring the detection accuracy in the resolver based on the square sum of the sine signal and the cosine signal, and an adjustment step of adjusting the balance of the output signal according to the detection accuracy obtained by monitoring.

According to such a monitoring method, it is possible to accurately monitor detection accuracy and correct imbalance using the sum of squares of the sine signal and the cosine signal.

According to the present invention, it is possible to monitor both changes in detection accuracy due to temperature drift and changes in detection accuracy due to imbalance between N phases.

1 is a diagram showing the overall configuration of a drive device including an angle detection device of this embodiment. FIG. 2 is a cross-sectional view showing the structure of a resolver. It is a graph showing resolver signals φA, φB, φC and temperature detection signal vt. It is a graph which shows the example of a signal when A phase is unbalanced with respect to other phases. It is a graph which shows the example of a signal when B phase is unbalanced with respect to other phases. It is a graph which shows the example of a signal when C phase is unbalanced with respect to other phases. It is a flowchart when signal processing of an angle detection device is realized by a program.

Embodiments of the present invention will be described below based on the drawings. However, in order to avoid the following explanation from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art, more detailed explanation than necessary may be omitted. For example, detailed explanations of well-known matters or redundant explanations of substantially the same configurations may be omitted. Further, elements shown in the previously described figures may be appropriately referred to in the explanation of later figures.

In this specification, embodiments of the present disclosure will be described using as an example a case where detection accuracy of a three-phase resolver having three-phase (A-phase, B-phase, C-phase) windings is monitored. However, monitoring the detection accuracy of an N-phase resolver having N-phase windings (N is an integer of 3 or more) including four-phase or five-phase windings is also within the scope of the present disclosure.

FIG. 1 is a diagram showing the overall configuration of a drive device 10 including an angle detection device 11 of this embodiment. FIG. 1 mainly shows the circuit configuration of the angle detection device 11. As shown in FIG.
The drive device 10 includes a motor 60 , a resolver 40 that outputs a resolver signal corresponding to the rotation angle of the rotation shaft of the motor 60 , and a drive unit 20 that drives the motor 60 . The drive unit 20 includes an angle detection device 11 that obtains a digital angle signal φ from a resolver signal, and a drive circuit 70. Although the resolver 40 is shown in the block of the angle detection device 11 in FIG. 1 for convenience, the resolver 40 can actually be incorporated into, for example, the motor 60 to detect the rotation angle of the rotation shaft. As the motor 60, for example, a direct drive motor is suitable, but a motor other than the direct drive motor may be used.

The drive circuit 70 drives the motor 60 based on the digital angle signal (signal indicating the electrical angle θ) output by the angle detection device 11.
The angle detection device 11 includes an oscillator 21, an amplifier 22, a current-voltage conversion circuit 23, a three-phase two-phase converter 24, an R/D converter (resolver digital converter) 25, and a temperature detection circuit 30. and a monitoring device 50. Further, the angle detection device 11 includes signal conditioners 26a, 26b, and 26c and a temperature compensator 27.

The oscillator 21 outputs an excitation signal (sine wave signal) of approximately several kHz. The amplifier 22 amplifies the excitation signal to a suitable signal level and supplies the amplified signal to the common terminal COM of the resolver 40 . The current-voltage conversion circuit 23 converts the current signal output from the resolver 40 into a voltage signal. The three-phase to two-phase converter 24 converts the three-phase signal into a two-phase signal (sin signal, cos signal). The R/D converter 25 converts the two-phase signal into a digital angle signal (signal indicating electrical angle θ). That is, the three-phase two-phase converter 24 and the R/D converter 25 obtain the electrical angle θ of the resolver 40 from the three-phase resolver signals. The temperature detection circuit 30 outputs a temperature detection signal vt corresponding to the temperature of the resolver 40.

The monitoring device 50 is configured by, for example, a CPU (central processing unit). As described later, the monitoring device 50 monitors the temperature and the detection accuracy of the resolver 40. The temperature compensator 27 performs temperature compensation of the detected angle according to the temperature monitored by the monitoring device 50. The signal adjusters 26a, 26b, and 26c adjust the signals according to the detection accuracy monitored by the monitoring device 50.

Here, the structure of the resolver 40 will be explained.
FIG. 2 is a cross-sectional view showing the structure of the resolver 40.
The resolver 40 includes a stator 43 and a hollow annular rotor 41. The resolver 40 shown as an example in FIG. 2 is a VR (variable reluctance) resolver.

The stator 43 has a plurality of externally toothed pole pieces 44 having a plurality of pole piece teeth 45 at their tips. The pole piece 44 is fixedly supported at each location equally dividing the circumference, and three-phase coils Ca, Cb, and Cc are wound around each pole piece 44 in order. Three-phase coils Ca, Cb, and Cc are connected in series for each phase.

The rotor 41 has internal teeth 42 formed opposite to the pole piece teeth 45 and arranged in the circumferential direction.
The winding direction of the coils Ca, Cb, and Cc wound around the A-phase, B-phase, and C-phase pole pieces 44 is set to a winding direction in which the polarity of adjacent pole pieces 44 of the same phase is reversed. For example, the coils are wired so that the winding directions are the same and the current flows alternately in opposite directions. Alternatively, the wire connection direction is the same, and the coil winding direction is alternately repeated clockwise (CW) and counterclockwise (CCW).

The rotor 41 and the stator 43 are arranged concentrically, and the reluctance of the gap (air gap) between the rotor 41 and the stator 43 changes depending on the rotational angular position of the rotor 41. The fundamental wave component of the reluctance change has a plurality of periods (the number of rotor teeth) in one rotation of the rotor 41. When an excitation signal is supplied to the common terminal of the coils Ca, Cb, and Cc, the three-phase coils Ca, Cb, and Cc output phase A, phase B, and phase C according to the rotational angular position of the rotor 41 with respect to the stator 43. A current signal is output. The A-phase, B-phase, and C-phase current signals are shifted from each other by an electrical angle of 120°.

Although an outer rotor type resolver is illustrated in FIG. 2 as the resolver 40, an inner rotor type resolver may also be used.
Returning to FIG. 1, the explanation will be continued.
In the angle detection device 11 that detects the rotation angle of the motor 60 using the resolver 40, if imbalance occurs in the three-phase electrical signals obtained by the resolver 40, the accuracy of angle detection changes. Changes in detection accuracy due to unbalance result in errors in the rotation control command for the motor 60, which causes vibrations in the rotation of the motor 60, deteriorating smooth rotational drive. Further, when the motor 60 is driven by a positioning angle, the positioning angle becomes deviated by the error.
Furthermore, it is difficult to measure position detection accuracy when the motor is driven in a high temperature environment. As a normal means for measuring the position detection accuracy, it is possible to arrange a reference encoder or the like on the motor 60 so as to face the resolver 40, and compare and measure the detection accuracy of the motor 60 between the reference encoder and the resolver 40. Further, by correcting the error between the resolver 40 and the reference encoder, it is possible to bring the accuracy closer to that of the reference encoder.
However, it is very difficult to arrange the reference encoders facing each other when the motor is rotating in a high-temperature environment. This is because the configuration in which the reference encoder is always incorporated into the motor 60 for monitoring purposes poses space and cost issues, and the high-precision reference encoder is used in a high-temperature environment because the operating environment temperature is lower than that of the resolver 40. This is because it is difficult to operate under such conditions.
In the angle detection device 11 of this embodiment, with the resolver 40 mounted on the motor 60, detection accuracy can be monitored and corrected even when driven in a high temperature environment, and highly accurate motor control is possible.
The current-voltage conversion circuit 23 includes sense resistors Ra1, Rb1, and Rc1 for converting current signals corresponding to the rotation angles of the rotor 41 for each of the A-phase, B-phase, and C-phase into voltage signals (resolver signals). The resolver signals of each phase obtained by the current-voltage conversion circuit 23 are as shown in equations (1) to (3) below, if high-order components are ignored. Here, for convenience of explanation, a case will be exemplified in which the phases of the B phase and the C phase are retarded at an electrical angle of 120 degrees and 240 degrees, respectively, with respect to the A phase as a reference.

φA=T・(Adc+Aac・sinθ)・sinωt… (1)
φB=T・{Bdc+Bac・sin(θ−120°)}・sinωt… (2)
φC=T・{Cdc+Cac・sin(θ−240°)}・sinωt… (3)
Here, T in equations (1) to (3) indicates the temperature coefficient of the coils Ca, Cb, and Cc, and the value of the temperature coefficient T increases as the environmental temperature of the resolver 40 becomes higher. Furthermore, ω is the angular frequency of transmission of the oscillator 21, and θ is the electrical angle generated by relative rotation of the rotor 41 and stator 43.

Resolver signals of each phase are input to signal conditioners 26a, 26b, and 26c, respectively.
The signal conditioners 26a, 26b, 26c are analog calculation means. Each signal adjuster 26a, 26b, 26c includes an operational amplifier OP, feedback resistors Ra3, Rb3, Rc3, input signal resistors Ra2, Rb2, Rc2, and adjustment signal resistors Ra4, Rb4, Rc4. Input signal resistors Ra2, Rb2, and Rc2 are provided between the current-voltage conversion circuit 23 and the non-inverting input terminal of the operational amplifier OP. Resistors Ra4, Rb4, and Rc4 for adjustment signals are provided between the input terminals for adjustment signals indicated by the circled numbers "1", "2", and "3" and the non-inverting input terminal of the operational amplifier OP. Adjustment signals are added to the resolver signals of each phase by signal adjusters 26a, 26b, and 26c. The adjustment signal is a signal that adjusts the DC component in the resolver signal of each phase. Details of the adjustment signal will be described later.

The three-phase resolver signals that have passed through the signal conditioners 26a, 26b, and 26c are input to the three-phase to two-phase converter 24 and converted into two-phase signals. Equations (4) and (5) below indicate two-phase signals sin and cos obtained by the 3/2-phase converter 24.
sin signal = φA-(φB+φC)/2... (4)
cos signal = sqr(3/4)・(φB−φC)…(5)

In equation (5), sqr(x) is a function that returns the square root of the argument x.
The two-phase signal obtained by the three-phase to two-phase converter 24 is input to the R/D converter 25. The R/D converter 25 converts the two-phase signal into a digital angle signal. The angle signal indicates an electrical angle θ, is outputted from the angle detection device 11 through temperature compensation by the temperature compensator 27, and is inputted to the drive circuit 70. Note that the drive circuit 70 has a function of calculating the rotation angle of the rotation shaft of the motor 60 from the electrical angle θ.

The three-phase resolver signals that have passed through the signal conditioners 26a, 26b, and 26c are also input to the temperature detection circuit 30.
The temperature detection circuit 30 includes an analog addition circuit 31, a demodulator 32, and an A/D converter 33. The analog addition circuit 31 is an analog calculation means, and includes an operational amplifier OP, a feedback resistor Rf, and resistors Ra5, Rb5, and Rc5. Resistors Ra5, Rb5, and Rc5 are provided between the signal conditioners 26a, 26b, and 26c and the non-inverting input terminal of the operational amplifier OP.

The analog adder circuit 31 adds the resolver signals φA, φB, and φC and outputs the temperature detection signal vt. The demodulator 32 demodulates the modulation component (sinωt) of the temperature detection signal vt to obtain a DC amplitude voltage VT. The A/D converter 33 converts the amplitude voltage VT into a digital value.

FIG. 3 is a graph schematically showing resolver signals φA, φB, φC and temperature detection signal vt.
In FIG. 3, each signal is shown as an envelope in which the modulation component (sinωt) is abstracted. The horizontal axis of the graph in FIG. 3 represents the electrical angle θ, and the vertical axis represents the signal strength.
The three-phase resolver signals φA, φB, and φC are out of phase with each other by 120 degrees, and the temperature detection signal vt, which is the sum of the three-phase resolver signals φA, φB, and φC, has an electrical angle of θ as shown in FIG. It is a constant value that does not depend on Even if the DC components of the three-phase resolver signals φA, φB, and φC become unbalanced among the three phases, the temperature detection signal vt shows a constant value. The amplitude voltage VT obtained from the temperature detection signal vt via the demodulator 32 and the A/D converter 33 indicates the temperature coefficient T of the coils Ca, Cb, and Cc and the environmental temperature.

The amplitude voltage VT output from the temperature detection circuit 30 shown in FIG. 1 is input to the temperature monitoring section 51 of the monitoring device 50. The temperature monitoring unit 51 monitors the environmental temperature indicated by the amplitude voltage VT, and calculates a temperature compensation value for the digital angle signal indicating the electrical angle θ based on the environmental temperature using any conventionally known method. According to another viewpoint, the temperature monitoring unit 51 monitors the environmental temperature in the N-phase (for example, three-phase) resolver 40 based on the sum of N-phase output signals in the resolver 40 . The temperature compensation value calculated by the temperature monitoring unit 51 is input to the temperature compensator 27, as indicated by the circled number "4", and is used for temperature compensation for the digital angle signal.

The two-phase signals sin and cos obtained by the three-phase two-phase converter 24 are converted into digital two-phase signals SIN and COS via the demodulator 34 and the A/D converter 35, and the monitoring device 50 calculates the sum of squares. 52. The sum of squares calculation unit 52 calculates the sum of squares E shown in equation (6) below.

E=sin ² θ+cos ² θ… (6)
The sum of squares E is input to the detection accuracy monitoring unit 53 of the monitoring device 50, and the detection accuracy is monitored in the detection accuracy monitoring unit 53 based on the sum of squares E. That is, the detection accuracy monitoring unit 53 monitors the detection accuracy in the resolver 40 using the sum of squares of the sine signal and the cosine signal obtained from the N-phase output signal by N-phase to two-phase conversion. The detection accuracy monitoring section 53 includes a monitoring section 54, a phase specifying section 55, and an adjustment value setting section 56.

The monitoring unit 54 of the detection accuracy monitoring unit 53 monitors the presence or absence of imbalance between the phases of the resolver signal based on the sum of squares E. Specifically, the presence or absence of imbalance is determined based on whether the value of the sum of squares E varies depending on the electrical angle θ.
From another perspective, the monitoring unit 54 monitors the detection accuracy using the difference between the local maximum value and the local minimum value in the sum of squares E as an index. Then, when the difference between the maximum value and the minimum value exceeds the threshold value, the monitoring unit 54 determines that an imbalance between the phases has occurred and detection accuracy has decreased.

When an unbalance occurs and the detection accuracy decreases, the phase specifying section 55 specifies the phase that is unbalanced with respect to other phases. The adjustment value setting unit 56 sets the adjustment amount for correcting the imbalance in the signal adjusters 26a, 26b, and 26c for the identified phase. That is, adjustment signals corresponding to the adjustment amount calculated by the adjustment value setting unit 56 are output from the monitoring device 50 as shown by the circled numbers "1", "2", and "3", and are sent to the signal adjusters 26a, 26b, 26c. By adding adjustment signals to the resolver signals in the signal adjusters 26a, 26b, and 26c, phase imbalance is corrected and detection accuracy is improved.

Here, specific processing in the detection accuracy monitoring section 53 will be explained based on a signal example.
4 to 6 are graphs schematically showing signal examples when unbalance occurs between phases. Each of the graphs in FIGS. 4 to 6 shows the two-phase signals SIN, COS, and the sum of squares E, and FIG. 4 shows a case where the A phase is unbalanced with respect to the other phases. Further, FIG. 5 shows a case where the B phase is unbalanced with respect to other phases, and FIG. 6 shows a case where the C phase is unbalanced with respect to other phases. The horizontal axis of each graph in FIGS. 4 to 6 indicates electrical angle, and the vertical axis indicates signal strength.

When the A phase is unbalanced with respect to the other phases, the signal strength of the sum of squares E shows a minimum or maximum at an electrical angle of ±90 degrees from 0 degrees. That is, when the DC component of the A phase is larger than the other phases, it shows a maximum at 90 degrees and a minimum at 270 degrees, as shown in FIG. 4(A). Furthermore, when the DC component of the A phase is smaller than the other phases, it shows a minimum at 90 degrees and a maximum at 270 degrees, as shown in FIG. 4(B).

When the B phase is unbalanced with respect to the other phases, the signal strength of the sum of squares E shows a minimum or maximum at an electrical angle of ±90 degrees with respect to 120 degrees. That is, when the DC component of the B phase is larger than the other phases, it shows a maximum at 210 degrees and a minimum at 30 degrees, as shown in FIG. 5(A). Furthermore, when the DC component of the B phase is smaller than the other phases, it shows a minimum at 210 degrees and a maximum at 30 degrees, as shown in FIG. 5(B).

When the C phase is unbalanced with respect to the other phases, the signal strength of the sum of squares E shows a minimum or maximum at an electrical angle of ±90 degrees with respect to 240 degrees. That is, when the DC component of the C phase is larger than the other phases, it shows a maximum at 330 degrees and a minimum at 150 degrees, as shown in FIG. 6(A). Furthermore, when the DC component of the B phase is smaller than the other phases, it shows a minimum at 330 degrees and a maximum at 150 degrees, as shown in FIG. 6(B).

The monitoring unit 54 of the detection accuracy monitoring unit 53 shown in FIG. 1 monitors the detection accuracy using the difference between the local maximum value and the local minimum value in the sum of squares E as an index, and when the difference between the local maximum value and the local minimum value exceeds a threshold value , it is determined that the detection accuracy has decreased due to an imbalance between the phases.
The phase identifying unit 55 identifies a phase that is unbalanced with respect to other phases based on the electrical angle θ at which the value of the sum of squares E is maximum or minimum.

That is, the phase specifying unit 55 determines the first electrical angle of (360°÷N)×M+90° and the first electrical angle of (360°÷N)×M− for the phase with phase number M (0 to N−1) in the N-phase resolver. The sum of squares E is monitored in at least one of the second electrical angles of 90°. Then, the phase identification unit 55 determines that the DC component has increased in the phase with phase number M when the value E increases at the first electrical angle and when the value E decreases at the second electrical angle. Further, the phase identification unit 55 determines that the DC component has decreased in the phase with phase number M when the value E decreases at the first electrical angle and when the value E increases at the second electrical angle.

The adjustment value setting unit 56 calculates an adjustment amount according to the difference between the maximum value and the minimum value as an adjustment amount according to the detection accuracy. Then, the adjustment value setting section 56 inputs the adjustment signal to the signal adjusters 26a, 26b, and 26c of the phase that is identified by the phase identification section 55 and is unbalanced with respect to other phases. As a result, the signal adjusters 26a, 26b, and 26c adjust the output signal of the phase that is unbalanced with respect to other phases by an adjustment amount that corresponds to the difference between the maximum value and the minimum value in the sum of squares. .
Here, a specific example of the adjustment amount will be explained.
For example, when only the DC component Adc in the A-phase resolver signal φA is 10.1 V, and the B-phase and C-phase DC components Bdc and Cdc are both 10 V, the waveform of sin ² θ + cos ² θ = E is as follows.
Electrical angle 0 degrees (=360 degrees): 4.02 [v ² ]
Maximum electrical angle: 90 degrees: 4.55 [v ² ]
Minimum electrical angle: 270 degrees: 3.48 [v ² ]
becomes. As described above, it is confirmed from the electrical angles of the maximum value and minimum value of the waveform that an unbalance has occurred in the A phase and whether the unbalance is positive or negative. Further, the adjustment amount obtained by multiplying the difference value between the local maximum value and the local minimum value = 4.55-3.48 = 1.07 by a predetermined coefficient is input to the A-phase signal adjuster 26a by the adjustment value setting section 56. , at least a portion of the imbalance is corrected. The coefficients are set to values depending on the resolver 40 and motor 60.
By repeating unbalance correction using such adjustment values, the DC component Adc in the A-phase resolver signal φA is lowered by 0.1v, and as a result, the waveform of the sum of squares E becomes 4.00[ ^v2] over the entire electrical angle. ].
By adjusting the three-phase resolver signals, the imbalance among the phases is corrected. Therefore, the temperature monitoring section 51 monitors the detection accuracy in the resolver 40 using the sum of squares obtained from the three-phase resolver signals adjusted based on the monitoring result by the detection accuracy monitoring section 53.
The unbalance between the phases affects the accuracy of angle detection by the resolver 40, and also affects the accuracy of temperature monitoring and temperature compensation for responding to changes in environmental temperature. Therefore, it is desired to improve the accuracy of drive control of the motor 60 by correcting the imbalance.
In the angle detection device 11 shown in FIG. 1, the imbalance between the phases is corrected by the adjustment signals input to the signal adjusters 26a, 26b, and 26c, thereby improving the detection accuracy of the electrical angle θ. Since the accuracy of the temperature detection signal vt is also improved, the accuracy of temperature compensation is also improved. Therefore, the accuracy of the digital angle signal indicating the electrical angle θ is improved, and the accuracy of drive control for the motor 60 is also improved.

In the angle detection device 11 shown in FIG. 1, a hardware calculation means is used in the temperature detection circuit 30, etc., but the angle detection device 11 performs signal processing by a program using the configuration shown in FIG. 1 as an equivalent circuit. It's okay.

FIG. 7 is a flowchart when the signal processing of the angle detection device 11 is implemented by a program.
When the program is started, three-phase resolver signals φA, φB, and φC are obtained from the resolver 40 in step S101. Then, in step S102, the three-phase resolver signals φA, φB, and φC are converted into two-phase signals (sin signal, cosine signal), and the electrical angle θ is calculated.

Thereafter, the processing in steps S103 to S106 and the processing in steps S107 to S109 are executed in parallel.
In step S103, a sum of squares E is calculated from the two-phase signals, and in step S104, detection accuracy is monitored based on the sum of squares E. In other words, in step S104, the detection accuracy in the resolver 40 is monitored based on the sum of squares of the sine signal and the cosine signal obtained from the N-phase (for example, 3-phase) output signal by N-phase to 2-phase conversion.

In step S105, the phase causing the imbalance is identified based on the presence of a maximum or minimum of the sum of squares E in the electrical angle corresponding to the phase number. In step S106, the resolver signal of the identified phase is adjusted based on the difference between the maximum and minimum in the sum of squares E. That is, in step S106, the balance of the output signal is adjusted according to the detection accuracy obtained by monitoring.

In step S107, three-phase resolver signals φA, φB, and φC are added, and in step S108, temperature monitoring is performed based on the added value. In other words, in step S108, the environmental temperature in the N-phase (for example, three-phase) resolver 40 is monitored based on the sum of the N-phase output signals of the N-phase (for example, three-phase) resolver 40. In step S109, temperature compensation is performed according to the monitored temperature.

In the angle detection device 11, temperature information and detection accuracy information are acquired only by arithmetic processing of resolver signals, so the temperature monitoring function and the detection accuracy monitoring function are realized without increasing the number of parts of the motor. Therefore, it is possible to simplify system design, save space and make the angle detection device 11 compact, and increase the reliability of the system.

The object of angle detection is not limited to a direct drive motor; for example, the angular position detection device 11 may be incorporated into an electric power steering device of a vehicle to detect the steering angle.

DESCRIPTION OF SYMBOLS 10... Drive device, 11... Angle detection device, 20... Drive unit, 21... Transmitter,
22... Amplifier, 23... Current-voltage conversion circuit, 24... Three-phase two-phase converter, 25... R/D converter,
26a, 26b, 26c...signal conditioner, 27...temperature compensator, 30...temperature detection circuit,
31... Analog addition circuit, 32, 34... Demodulator, 33, 35... A/D converter,
40... Resolver, 50... Monitoring device, 51... Temperature monitoring section, 52... Square sum calculation section,
53...Detection accuracy monitoring section, 54...Monitoring section, 55...Phase identification section, 56...Adjustment value setting section,
60...Motor, 70...Drive circuit

Claims (7)

a monitoring unit that monitors the detection accuracy in the N-phase (N is an integer of 3 or more) resolver based on the sum of squares of a sine signal and a cosine signal obtained from the N-phase output signal in the N-phase resolver through N-phase to two-phase conversion;
an adjustment unit that adjusts the balance of the output signal according to the detection accuracy obtained by monitoring;
A monitoring device characterized by comprising: The monitoring device according to claim 1, wherein the adjustment unit adjusts the output signal of a phase that is unbalanced with respect to other phases among the N phases. The monitoring device according to claim 1, wherein the adjustment unit adjusts the output signal by an adjustment amount according to a difference between a local maximum value and a local minimum value in the sum of squares. The monitoring unit determines a first electrical angle of (360°÷N)×M+90° and a first electrical angle of (360°÷N)×M−90 for a phase with a phase number M (0 to N−1) among the N phases. The value E of the sum of squares is monitored at at least one of the second electrical angles of °, and when the value E increases at the first electrical angle and when the value E decreases at the second electrical angle, the phase number M It is determined that the DC component has increased in the phase of phase number M, and if the value E has decreased in the first electrical angle and the value E has increased in the second electrical angle, the DC component has decreased in the phase of phase number M. The monitoring device according to claim 1, wherein the monitoring device determines that. The monitoring device according to claim 1, further comprising a temperature monitoring section that monitors the environmental temperature in the resolver based on the sum of the output signals adjusted by the adjustment section. an N-phase resolver (N is an integer of 3 or more);
an angle detection unit that obtains the electrical angle θ of the resolver from the output signal of the resolver;
a monitoring unit that monitors detection accuracy in the resolver based on the sum of squares of a sine signal and a cosine signal obtained from the N-phase output signal of the resolver through N-phase to two-phase conversion;
an adjustment unit that adjusts the balance of the output signal according to the detection accuracy obtained by monitoring;
An angle detection device characterized by comprising: a monitoring step of monitoring the detection accuracy in the N-phase (N is an integer of 3 or more) resolver based on the sum of squares of a sine signal and a cosine signal obtained from the N-phase output signal in the N-phase resolver through N-phase to two-phase conversion;
an adjusting step of adjusting the balance of the output signal according to the detection accuracy obtained by monitoring;
A monitoring method in a monitoring device, characterized in that it has the following.

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