JP2014122884A - Angle detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an angle detector for detecting an angle of a resolver, that can stably detect an angle with high accuracy at all times.SOLUTION: An angle detector includes: two AD converters 103 and 104 for performing digital conversion of two resolver output signals at their respective predetermined sampling timings; a signal generation unit 11 for generating an excitation signal and a sampling signal for the sampling timings; a timing adjustment unit 102 for adjusting timings of the signals generated by the signal generation unit 11; an RD conversion unit 105 for calculating an angle of a resolver; and a vector length calculation unit 106 for calculating a vector length from output values of both of the AD converters 103 and 104. The timing adjustment unit 102 adjusts the timings so that the vector length becomes an extreme value.

Description

  The present invention relates to a resolver angle detection device for one-phase excitation and two-phase output.

  Conventionally, a resolver is often used as a means for detecting the angular position of a motor, mainly in the industrial field and electrical equipment field.

  FIG. 10 shows a configuration example in which the angular position of the motor is detected by a resolver attached to the motor shaft, and the motor is controlled based on the detected angular position.

  FIG. 10 is a block diagram showing a conventional resolver angle detection device 1102 described in Patent Document 1. In FIG. The resolver 20 is a one-phase excitation two-phase output method and is attached to the shaft of the motor 30. The resolver 20 outputs a two-phase signal of A phase and B phase. The angle detection device 1102 detects the angular position of the resolver from the two-phase signal and outputs it to the servo amplifier 112. The servo amplifier 112 controls and drives the motor 30 according to the detected angular position. Further, an excitation signal is output from the angle detection device 1102 and excites the resolver 20 via the buffer circuit 111.

  Next, the internal configuration of the resolver angle detection device 1102 will be described. The angle detection device 1102 includes AD converters 103 and 104 that are analog-digital converters. The AD converters 103 and 104 convert the A-phase and B-phase analog signals output from the resolver 20 into digital values, respectively. The conversion timing follows the sampling signal output from the sampling signal generation unit 1107. The A-phase and B-phase signals converted into digital values by the AD converters 103 and 104 are converted into signals indicating the angular position of the resolver 20 in the RD conversion unit 105 (a method such as a tracking loop is generally used). . A signal indicating the angular position is output to the servo amplifier 112 via the interface processing unit 101. The servo amplifier 112 controls and drives the motor 30 according to the detected angular position of the resolver 20, that is, the angular position of the motor 30.

  The sampling signal generation unit 1107 adjusts the phase based on the reference signal output from the reference signal generation unit 108 and outputs the sampling signal to the AD converters 103 and 104. The excitation signal generator 109 generates and outputs an excitation signal based on the reference signal output from the reference signal generator 108.

  FIG. 11A shows the A-phase and B-phase signals output from the resolver 20. FIG. 11B shows a reference signal output from the reference signal generation unit 108. The sampling signal generator 1107 adjusts the phase based on this reference signal and outputs a sampling signal. In this case, the absolute values of the A-phase and B-phase signals output from the resolver 20 are maximized at times t92 and t94, so that sampling signals are output at this timing. However, there is a method in which the times t92 and t94 are obtained by detecting times t91 and t93 at which the A phase and B phase signals become zero and adding a time corresponding to ¼ of one period to the detected times. In this way, a signal with a good S / N ratio can be obtained by analog-to-digital conversion of each signal at the timing when the absolute value of each of the A-phase and B-phase signals is maximized in one cycle of the excitation signal. The angular position of the resolver can be detected with high accuracy.

JP 2011-33602 A

  However, in the above-described conventional configuration, the maximum value or the minimum value of each of the A-phase and B-phase signals is detected separately, and the signal output from the resolver is amplitude-modulated according to the angular position. For this reason, depending on the rotational speed or angular position of the resolver, there is a problem that it is difficult to accurately detect the timing when the maximum value or the minimum value is reached.

  That is, since the A phase and the B phase have a phase difference of 90 degrees in the angular position, the B phase signal has the minimum amplitude (uniformly zero or close to zero when the A phase signal has the maximum amplitude. Conversely, when the B phase signal has the maximum amplitude, the A phase signal has the minimum amplitude. For this reason, in the correction of the sampling timing, if a phase signal having a minimum amplitude due to an angular position or the like is used, for example, the zero-cross position cannot be detected accurately, and the timing accuracy also deteriorates.

  The present invention solves such a conventional problem, and stably detects the maximum value or the minimum value of each signal of the A phase and the B phase irrespective of the rotational speed or the angular position of the resolver, An object of the present invention is to provide an angle detection device that can easily and surely correct the timing of a sampling signal even when a temperature change or a change with time occurs, and that can stably and accurately detect an angular position.

  In order to achieve the above object, the angle detection device of the present invention provides a first resolver output signal and a second resolver output signal output from a resolver so that the excitation signal is amplitude-modulated with a phase difference of 90 degrees. An angle detection device that detects a rotation angle based on the angle. The angle detection apparatus includes a first AD converter and a second AD converter that digitally convert a first resolver output signal and a second resolver output signal at predetermined sampling timings, an excitation signal, and the sampling signal. A signal generation unit that generates and outputs a timing sampling signal, a timing adjustment unit that adjusts timing of a signal generated by the signal generation unit, and outputs of each of the first AD converter and the second AD converter An angle calculator that calculates the angle of the resolver from the value, and a vector length calculator that calculates the magnitude of the vector from the output values of the first AD converter and the second AD converter. And this angle detection apparatus is a structure which a timing adjustment part performs timing adjustment so that the magnitude | size of a vector may become an extreme value.

  Furthermore, the angle detection device of the present invention is configured such that the timing adjustment unit adjusts the timing of the sampling timing so that the magnitude of the vector becomes an extreme value.

  In addition, the angle detection device of the present invention may be configured such that the timing adjustment unit adjusts the timing of the phase of the excitation signal so that the magnitude of the vector becomes an extreme value.

  With such a configuration, it is only necessary to detect the maximum or minimum timing of a single signal, which is the output value of the vector length calculation unit, so it is necessary to detect changes in separate resolver output signals of A phase and B phase. There is no. As a result, the timing at which each of the A phase and B phase signals becomes maximum can be detected stably and accurately, so that the timing of the sampling command signal can be easily and accurately corrected. The angular position can always be detected stably and accurately.

  The angle detection apparatus according to the present invention can automatically adjust the timing including variations in the characteristics of the resolver, temperature changes, changes with time, etc., and can always detect the angular position of the resolver stably and accurately.

1 is a block diagram of a motor control device including a resolver angle detection device according to Embodiment 1 of the present invention. Same as above, timing chart showing main signal waveforms of angle detector The timing chart showing the waveform of each signal in the case of another configuration example of the angle detection device The block diagram which shows the detailed structure of the excitation signal generation part of an angle detection apparatus similarly The timing chart showing the waveform of each signal in the excitation signal generator of the angle detector The figure for demonstrating an example which adjusts the amplitude of the excitation signal of an angle detection apparatus to an optimal value similarly Waveform diagram showing change in maximum value of vector length when signal line of either A phase or B phase is disconnected The block diagram of the motor control apparatus containing the angle detection apparatus of the resolver in Embodiment 2 of this invention Same as above, timing chart showing main signal waveforms of angle detector Block diagram of a motor control device including a conventional resolver angle detection device Timing chart showing waveforms of signals in a conventional angle detector

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a block diagram of a motor control device including a resolver angle detection device according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the motor control device 100 includes an angle detection device 10 that detects the angular position of the rotor of the motor 30 using a resolver 20.

  In FIG. 1, the resolver 20 is a one-phase excitation two-phase output method and is attached to a motor 30. The resolver 20 outputs a two-phase signal of A phase and B phase. As an example of the configuration of a one-phase excitation two-phase output type resolver, the resolver 20 includes an excitation coil 21 and two detection coils 22 and 23 as schematically shown in FIG. The exciting coil 21 is disposed in the rotating unit 26, and the rotating unit 26 is connected to a rotor and a rotating shaft of the motor 30. Further, an excitation signal is supplied to the excitation coil 21. On the other hand, the detection coils 22 and 23 are arrange | positioned at the fixing | fixed part 25 so that an arrangement | positioning angle may mutually differ only 90 degree | times, for example. With such a configuration of the resolver 20, the excitation coil 21 to which the excitation signal is supplied rotates as the motor 30 rotates. The detection coils 22 and 23 output signals generated by electromagnetic induction of excitation signals. Here, when the excitation coil 21 and the detection coil 22 are in a parallel positional relationship, a signal having a maximum amplitude is output from the detection coil 22. At this time, since the excitation coil 21 and the detection coil 23 are in a positional relationship orthogonal to each other, the detection coil 23 outputs a signal having a minimum amplitude (uniformly zero or an amplitude close to zero). A signal having an amplitude corresponding to the rotational position is output from the detection coil 22 and the detection coil 23 according to the rotational position. That is, when the resolver 20 operates in this way, the A-phase signal va is output from the detection coil 22 and the detection coil 23 outputs the amplitude signal from the resolver 20 so that the excitation signal is amplitude-modulated with a phase difference of 90 degrees. A B-phase signal vb is output. As the excitation signal, for example, a sine wave signal having a frequency of 10 KHz is generally used.

  The A-phase signal va as the first resolver output signal output from the resolver 20 and the B-phase signal vb as the second resolver output signal are supplied to the angle detection device 10. The angle detection device 10 detects the angular position of the resolver 20, that is, the angular position that is the rotation angle of the rotor of the motor 30 from the two-phase signals, and outputs a signal corresponding to the detected angular position to the servo amplifier 112. . The servo amplifier 112 performs rotation control and driving of the motor 30 according to the detected angular position. Further, an excitation signal sc is output from the angle detection device 10 to excite the excitation coil 21 of the resolver 20 via the buffer circuit 111.

  Next, the internal configuration of the angle detection device 10 will be described. As shown in FIG. 1, the angle detection apparatus 10 includes an analog-digital converter (hereinafter referred to as an AD converter) 103 that is a first AD converter, an AD converter 104 that is a second AD converter, and an angle calculation. RD conversion unit 105, vector length calculation unit 106, timing adjustment unit 102, interface processing unit (hereinafter referred to as I / F processing unit) 101, and signal generation unit 11.

  The AD converters 103 and 104 convert the analog signals of the A-phase signal va and B-phase signal vb output from the resolver 20 into digital values, respectively, at a predetermined sampling timing. In addition, the signal generator 11 generates a sampling signal fs to be supplied to the AD converters 103 and 104 together with the excitation signal sc for exciting the excitation coil 21. The AD converters 103 and 104 perform digital conversion at the sampling timing indicated by the sampling signal fs. The signals converted into digital values by the AD converters 103 and 104 are supplied to an RD converter 105, what is called a so-called resolver-digital converter. The RD conversion unit 105 converts each of the output values of the AD converters 103 and 104 into an angle detection signal ag indicating the angular position of the resolver 20 (generally, a method such as a tracking loop is used), and thereby the resolver 20 Is calculated. The angle detection signal ag is output to the servo amplifier 112 via the interface processing unit 101 that interfaces the angle detection device 10 and the servo amplifier 112. The servo amplifier 112 controls and drives the motor 30 according to the detected angular position of the resolver 20, that is, the angular position of the motor 30.

  The signal generation unit 11 includes a reference signal generation unit 108, a sampling signal generation unit 107, and an excitation signal generation unit 109. The reference signal generation unit 108 includes an oscillator that generates a sine wave or rectangular wave having a predetermined frequency, which is generally called a clock signal. The reference signal generation unit 108 further generates and outputs a reference signal ss with reference timing using the signal from the oscillator. The signal generator 11 generates various signals based on the reference signal ss. That is, the sampling signal generation unit 107 adjusts the phase based on the reference signal ss output from the reference signal generation unit 108 to generate the sampling signal fs, and outputs the sampling signal fs to the AD converters 103 and 104. The excitation signal generation unit 109 generates and outputs an excitation signal sc based on the reference signal ss output from the reference signal generation unit 108.

  As a specific example of the signal generation unit 11, the signal generation unit 11 may be configured as follows. The reference signal generator 108 includes a 10 MHz signal oscillator and a counter that divides the oscillation signal. By dividing such an oscillation signal by 1/1000, a signal of 10 kHz can be obtained. The reference signal generation unit 108 supplies the 10 KHz signal to the excitation signal generation unit 109 as the reference signal ss. The excitation signal generation unit 109 generates a 10 KHz sine wave signal using the reference signal ss and outputs it as an excitation signal sc. On the other hand, the sampling signal generation unit 107 generates a signal having a frequency that is an integral multiple of the reference signal ss. For example, by setting the sampling signal fs at 40 KHz, which is four times the reference signal ss, the AD converters 103 and 104 sample four samples per cycle with respect to the A-phase signal va and B-phase signal vb at 10 KHz. . Note that these frequencies are examples, and may be changed as appropriate.

  Furthermore, the angle detection apparatus 10 includes a vector length calculation unit 106 and a timing adjustment unit 102 in order to set the sampling timing of the sampling signal fs, that is, the sampling phase of the sampling signal fs, to an appropriate phase. The vector length calculation unit 106 calculates the magnitude of the vector from the output values of the AD converters 103 and 104, and outputs the calculated magnitude as a vector length value vl. Based on the vector length value vl supplied from the vector length calculation unit 106, the timing adjustment unit 102 adjusts the timing of the sampling signal fs generated by the sampling signal generation unit 107 so that the vector length value vl becomes an extreme value. . That is, the timing adjustment unit 102 outputs the phase adjustment signal dp to the sampling signal generation unit 107 so that the vector length value vl becomes the maximum value or the minimum value, and controls the sampling phase of the sampling signal fs. For example, when controlling the vector length value vl to be the maximum value, the timing adjustment unit 102 changes the phase of the sampling signal fs in the delay direction, for example, and if the vector length value vl becomes small at this time, Change the direction. Conversely, if the vector length value vl increases, the vector length value vl is further changed in the delay direction. The timing adjustment unit 102 sequentially repeats such control so that the vector length value vl converges to the sampling phase where the vector length value vl becomes the maximum value. The sampling signal fs is supplied to the AD converters 103 and 104 at the sampling timing at which the vector length value vl becomes the maximum value. That is, in this embodiment, the AD converters 103 and 104, the vector length calculation unit 106, the timing adjustment unit 102, and the sampling signal generation unit 107 feed back the sampling signal fs so that the vector length value vl becomes an extreme value. A phase control loop for phase control is configured. Further, in the present embodiment, by configuring such a phase control loop using the vector length value vl calculated by the vector length calculation unit 106, the sampling signal fs is stabilized and the angular position of the angle is stable and accurate. Detection is planned.

  In the above description, the RD conversion unit 105, the vector length calculation unit 106, the timing adjustment unit 102, and the interface processing unit 101 have been described as individual functional blocks. However, with respect to these digital value processing blocks, a microcomputer or the like is used. You may carry out by the process by this program execution.

  The operation | movement and effect | action are demonstrated below about the angle detection apparatus 10 of the resolver 20 in the motor control apparatus 100 comprised as mentioned above.

FIG. 2 is a timing chart showing main signal waveforms of the angle detection apparatus 10 according to the first embodiment of the present invention. 2A is a waveform of the A phase signal va and the B phase signal vb, FIG. 2B is a waveform indicating the vector length value vl, FIG. 2C is a waveform of the reference signal ss, and FIG. 2 (d) shows an example of the waveform of the sampling signal fs. Further, the left side of FIG. 2 shows each waveform in a period of approximately one and a half cycles of the excitation signal sc near the time when the angular position θ of the resolver 20 becomes θ ₀ . The right side of FIG. 2 shows each waveform in the period of approximately one and a half cycles of the excitation signal sc near the time when the angular position θ is θ ₁ . As is generally known, each signal of the A phase and B phase in the resolver is a signal obtained by amplitude-modulating the excitation signal sc (= sin ωt) inside the resolver, but is amplitude-modulated with a phase difference of 90 degrees from each other. . For this reason, as illustrated in FIG. 2A, the amplitude of the A-phase signal va is larger than that of the B-phase signal vb near the time when the angular position θ becomes θ _0, and as time passes, Near the time when the angular position θ is θ _1, the amplitude of the B-phase signal vb is larger than that of the A-phase signal va. As described above, the A-phase signal va and the B-phase signal vb change in accordance with the excitation signal sc as well as the angular position θ while maintaining a phase difference of 90 degrees as the angular position.

  Thus, if the angular position of the resolver 20 is θ, the A-phase signal va can be expressed as Asinθsinωt, and the B-phase signal vb can be expressed as Acosθsinωt. Here, Asinθ and Acosθ mean the amplitude of the signal, which is a phase difference of 90 degrees. That is, the A-phase signal va is a signal in which the excitation signal sc of (sin ωt) is amplitude-modulated by Asin θ, and the B-phase signal vb is a signal in which the excitation signal sc of (sin ωt) is amplitude-modulated by Acos θ. In particular, when the absolute value of the amplitude of the A phase signal va is maximum, that is, “A”, the amplitude of the B phase signal vb is zero, and when the absolute value of the amplitude of the B phase signal vb is maximum, that is, “A”, The amplitude of the A phase signal va is zero.

  The RD conversion unit 105 calculates the ratio of both output values from the output value of the AD converter 103 corresponding to the amplitude Asinθ of the A-phase signal va and the output value of the AD converter 104 corresponding to the amplitude Acosθ of the B-phase signal vb, that is, ( A value corresponding to (Asin θ / A cos θ) is obtained. Further, the RD conversion unit 105 calculates the angular position θ of the resolver 20 by obtaining an arc tangent (arcTan) of this value.

  Further, since the A-phase signal va and the B-phase signal vb are amplitude-modulated with a phase difference of 90 degrees, when these two signals are considered as vectors, the vector length, which is the magnitude of the vector, is the square root of the following equation: Become.

(Asin θ sin ωt) ² + (A cos θ sin ωt) ² = (Asin ωt) ²
That is, the vector length is | Asinωt | (the absolute value of Asinωt). This is shown in FIG.

  When the angular position θ of the resolver 20 changes, the amplitudes of the A-phase signal va and the B-phase signal vb also change as described above. On the other hand, as shown in FIG. 2B, the vector length described above is always a constant amplitude regardless of the angular position θ of the resolver 20, that is, the amplitude “A”, and the reference signal ss and the A phase signal. The signals are synchronized with the va and B phase signals vb. Therefore, even when the resolver 20 is rotating, it is easy to accurately detect the timing at which the vector length is maximum or minimum, and the optimum sampling signal fs output from the sampling signal generator 107 is thereby detected. Timing can be determined.

  That is, in the state shown in FIG. 2, for example, the vector length becomes maximum at times t1 and t3, and by outputting the sampling signal fs at this timing, the S / N ratio is the highest in A-phase and B-phase analog-digital conversion. A good sampling signal fs. As a result, a signal for detecting the angular position of the resolver 20 with a good SN ratio is obtained. Also, for example, by detecting times t2 and t4 at which the vector length is minimum, it is easy to output the sampling signal fs at times t1 and t3 by shifting the period by 1/4.

  As described above, in this embodiment, the sampling timing is corrected using the vector length independent of the angular position θ, and the sampling timing is corrected using the A-phase and B-phase signals. Compared to, the correction amount is obtained with higher accuracy. In the present embodiment, the sampling signal fs is generated using the correction amount obtained with high accuracy, and the angle detection signal ag having a good SN ratio is obtained.

  Next, a configuration and operation for adjusting the phase of the sampling signal fs in the present embodiment for correcting such sampling timing will be described.

  The reference signal ss output from the reference signal generation unit 108 is shown in FIG. The reference signal ss having a waveform as illustrated in FIG. 2C is obtained by, for example, counting a clock signal of an oscillator provided in the reference signal generation unit 108 with a counter and converting the counter output into an analog signal with a DA converter. Can be generated. More specifically, for example, a reference signal ss having a waveform as shown in FIG. 2C can be obtained at 10 KHz by repeating counting of a clock signal of 10 MHz for 1000 clocks with a counter.

  The excitation signal sc (= sin ωt) is generated by the excitation signal generation unit 109 based on such a reference signal ss and then input to the resolver 20 via the buffer circuit 111. Therefore, the phase relationship between the reference signal ss and the A-phase signal va and B-phase signal vb is influenced by the phase delay, delay, etc. in the transmission process from the reference signal ss to the digital value converted by the AD converters 103 and 104. receive. In addition, the phase lag may be affected by temperature changes and changes with time, so that phase adjustment is required. In FIG. 2, when the amplitude of the excitation signal sc is maximized with respect to the falling time t0 and time t10 when the reference signal ss changes significantly, the A-phase signal va and B-phase signal vb are in phase until the time t1 and time t11. The case where a delay occurs is shown. When AD conversion is performed at such a phase-delayed timing, a value shifted from the maximum value of the vector length value vl as shown in FIG. 2B is taken in, and the SN ratio is deteriorated as described above. Invite.

  In the present embodiment, the timing adjustment unit 102 adjusts the phase of the sampling signal fs generated by the sampling signal generation unit 107 in order to suppress the influence due to such phase delay.

  FIG. 2D shows an example of the sampling signal fs generated by the sampling signal generation unit 107. Here, an example is shown in which sampling is performed four times during one cycle of the reference signal ss.

  As shown in FIG. 2, the timing adjustment unit 102 supplies a phase adjustment signal dp that is a phase correction amount DP to the sampling signal generation unit 107. For this reason, the AD converters 103 and 104 capture both signals in such a phase as to sample the maximum values of the A-phase signal va and the B-phase signal vb. In this embodiment, the vector length value vl calculated by the vector length calculation unit 106 is used to generate a sampling timing at which the vector length value vl becomes the maximum value. In the present embodiment, the vector length value vl that is the maximum value is sampled by the phase control loop that performs feedback phase control as described above. Further, as described above, it may be a phase control loop that generates a sampling timing at which the vector length value vl becomes the minimum value.

  Thus, since the sampling signal generation unit 107 is configured to determine the optimum timing of the sampling signal fs from the output signal of the vector length calculation unit 106, the phase of the sampling signal fs with respect to the reference signal ss is automatically set. As a result, the angle detection signal ag of the resolver 20 having a good SN ratio can be obtained.

  That is, with the configuration shown in FIG. 1, the angle detection of the resolver 20 can always be performed stably and with high accuracy.

In the above description, the calculation of the vector length usually requires the calculation of the square root, but the calculation of the square root may be omitted because of the processing time and the like. FIG. 3 is a timing chart when the square root calculation is omitted, and FIG. 3B shows the case where the square root calculation is omitted. 3A and 3C are the same as FIGS. 2A and 2C, respectively. That is, even if the timing at which the maximum value or the minimum value of (A phase ² + B phase ² ) is detected, the result is the same as the above-described configuration.

  Next, a configuration example of the excitation signal generation unit 109 described above will be described. FIG. 4 is a block diagram illustrating a configuration example of the excitation signal generation unit 109. FIG. 5 is a timing chart showing the waveform of each signal of the excitation signal generator 109.

  As shown in FIG. 4, the excitation signal generation unit 109 includes a rectangular wave pulse generation unit 191, an amplitude adjustment unit 192, and a switched capacitor filter 193. The rectangular wave pulse generator 191 receives the reference signal ss shown in FIG. 5A and outputs a rectangular wave pulse shown in FIG. The amplitude adjusting unit 192 receives the rectangular wave pulse shown in FIG. 5B, attenuates the amplitude at a set predetermined ratio, and outputs the attenuated. This signal is shown in FIG. Specifically, the amplitude adjustment unit 192 can be realized by a device such as an electronic volume. The switched capacitor filter 193 has a steep low-pass filter characteristic. The switched capacitor filter 193 receives the pulse signal output from the amplitude adjustment unit 192, significantly attenuates the harmonics, and converts it into a sine wave that is a fundamental wave and outputs it. This signal is output as an excitation signal sc as shown in FIG. In this case, the cut-off frequency of the switched capacitor filter 193 is determined by the frequency of the clock signal sck for controlling the switched capacitor filter input thereto. Here, in order to attenuate the harmonics effectively, it is necessary to set a value slightly larger than the fundamental frequency, for example, about 1.2 times the fundamental frequency.

  Conversely, when this property is applied, when the frequency of the excitation signal sc is to be switched, the frequency of the reference signal ss is switched, and at the same time, the frequency of the clock signal sck input to the switched capacitor filter 193 is also switched proportionally. Switching of the excitation signal frequency can be easily realized.

  Furthermore, the amplitude of the excitation signal sc can be adjusted by changing the setting of the attenuation rate of the amplitude adjusting unit 192. For example, the amplitude of the excitation signal sc is changed by changing the setting of the attenuation rate of the amplitude adjustment unit 192 so that the maximum value (time t1 and t3 in FIG. 2) of the output of the vector length calculation unit 106 becomes a predetermined value. Can be adjusted to an optimum value. In general, the excitation signals sc so that the amplitudes of the A-phase signal va and the B-phase signal vb input to the AD converters 103 and 104 do not exceed the input range of the AD converters 103 and 104 and are as large as possible. By adjusting the amplitude of, an angle detection operation with a good SN ratio and high accuracy becomes possible.

  FIG. 6 is a diagram for explaining an example of adjusting the amplitude of the excitation signal sc to an optimum value. FIG. 6 shows an example in which the setting of the attenuation rate of the amplitude adjusting unit 192 is changed and the amplitude of the excitation signal sc is adjusted to an optimum value in the process of initial adjustment at power-on, and the change in the maximum value of the vector length is shown. Is shown. Since the amplitude of the excitation signal sc is increased from the time t30 and the maximum value of the vector length becomes an appropriate value at the time t31, the adjustment of the attenuation rate of the amplitude adjusting unit 192 is ended and the amplitude of the excitation signal is fixed. Yes.

  If the maximum vector length cannot be adjusted to an appropriate value during the initial adjustment process, it is determined that some abnormality has occurred in the angle detection device 10 of the resolver 20, and the angle detection device 10 is connected to the servo amplifier 112. On the other hand, by outputting an error, it is possible to avoid dangers associated with motor control and driving.

  In addition, by constantly monitoring the maximum value of the vector length, for example, it is possible to determine when any abnormality occurs in the signal from the resolver 20 due to disconnection or the like. FIG. 7 shows a change in the maximum value of the vector length when one of the A-phase signal va and the B-phase signal vb is disconnected at time t40 while the motor 30 is rotating. . Thus, when the value fluctuates beyond the predetermined allowable value ΔL set as the amount of change in the maximum value of the vector length, it can be determined that an abnormality has occurred in the signal from the resolver 20. Based on such a determination, the angle detection device 10 outputs an error to the servo amplifier 112, so that it is possible to avoid dangers associated with motor control and driving.

(Embodiment 2)
FIG. 8 is a block diagram of a motor control device including a resolver angle detection device according to Embodiment 2 of the present invention.

  As shown in FIG. 8, in the present embodiment, the motor control device 400 is configured to include an angle detection device 40 that detects the angular position of the rotor of the motor 30 using the resolver 20. The angle detection device 40 of the present embodiment is different from the angle detection device 10 of the first embodiment shown in FIG.

  In the signal generation unit 41, the sampling signal generation unit 407 is different from the sampling signal generation unit 107 of the first embodiment, and does not adjust the phase based on the reference signal ss output from the reference signal generation unit 108. fs is output to the AD converters 103 and 104. Conversely, unlike the excitation signal generation unit 109 of the first embodiment, the excitation signal generation unit 409 uses the phase adjustment signal dp from the timing adjustment unit 102 based on the reference signal ss output from the reference signal generation unit 108. The excitation signal sc is generated by adjusting the phase and output.

  In this embodiment, with such a configuration, the AD converters 103 and 104, the vector length calculation unit 106, the timing adjustment unit 102, and the excitation signal generation unit 409 are excited so that the vector length value vl becomes an extreme value. This constitutes a phase control loop for feedback phase control of the signal sc.

  For example, when controlling the vector length value vl to be the maximum value, the timing adjustment unit 102 changes the phase of the excitation signal sc in the delay direction, for example, and if the vector length value vl becomes small at this time, Change the direction. Conversely, if the vector length value vl increases, the vector length value vl is further changed in the delay direction. When the timing adjustment unit 102 sequentially repeats such control on the excitation signal generation unit 409, it converges to the sampling phase where the vector length value vl becomes the maximum value. The sampling signal fs is supplied to the AD converters 103 and 104 at the sampling timing at which the vector length value vl becomes the maximum value.

  The operation | movement and effect | action are demonstrated below about the angle detection apparatus 40 of the resolver 20 in the motor control apparatus 400 comprised as mentioned above.

  Waveform diagrams of each signal in the angle detection device 40 shown in FIG. 8 are shown in FIGS. The sampling signal generation unit 407 outputs the sampling signal fs to the AD converters 103 and 104 at the overflow times t50 and t52 of the reference signal ss shown in FIG. The excitation signal generation unit 409 outputs the reference signal output from the reference signal generation unit 108 so that the vector length value vl output from the vector length calculation unit 106 shown in FIG. 9B becomes maximum at times t50, t51, and t52. The phase is adjusted by the timing adjustment unit 102 based on ss, and the excitation signal sc adjusted in this way is generated and output. As a result, the amplitudes of the A-phase signal va and B-phase signal vb shown in FIG. 9A are converted to digital values by the AD converters 103 and 104 at the best signal-to-noise ratio at times t50, t51, and t52. become.

  Thus, in the present embodiment, the phase of the excitation signal sc can be automatically and optimally adjusted based on the reference signal ss, and as a result, the angle detection signal ag of the resolver 20 with a good SN ratio can be obtained.

  That is, with the configuration shown in FIG. 8, the angle of the resolver can always be detected stably and with high accuracy.

  As described above, the resolver angle detection device according to the present invention is capable of automatic timing adjustment, including resolver characteristic variation, temperature change or change over time, and always provides a stable and accurate resolver angle. Position detection is possible. Therefore, it can be applied to industrial FA servo motors.

10, 40, 1102 Angle detection device 11, 41 Signal generation unit 20 Resolver 21 Excitation coil 22, 23 Detection coil 25 Fixed unit 26 Rotation unit 30 Motor 100, 400 Motor control device 101 Interface processing unit 102 Timing adjustment unit 103, 104 AD Converter 105 RD conversion unit 106 Vector length calculation unit 107,407,1107 Sampling signal generation unit 108 Reference signal generation unit 109,409 Excitation signal generation unit 111 Buffer circuit 112 Servo amplifier 191 Rectangular wave pulse generation unit 192 Amplitude adjustment unit 193 Switched capacitor filter

Claims (6)

An angle detection device that detects a rotation angle based on a first resolver output signal and a second resolver output signal output from a resolver such that an excitation signal is amplitude-modulated with a phase difference of 90 degrees,
A first AD converter and a second AD converter for digitally converting the first resolver output signal and the second resolver output signal, respectively, at a predetermined sampling timing;
A signal generator that generates and outputs an excitation signal and a sampling signal of the sampling timing;
A timing adjustment unit that adjusts timing of a signal generated by the signal generation unit;
An angle calculator that calculates an angle of the resolver from output values of the first AD converter and the second AD converter;
A vector length calculation unit that calculates a vector size from output values of the first AD converter and the second AD converter,
The angle detection device, wherein the timing adjustment unit adjusts the timing so that the magnitude of the vector becomes an extreme value. The angle detection apparatus according to claim 1, wherein the timing adjustment unit adjusts the timing of the sampling timing so that the vector has an extreme value. The angle detection device according to claim 1, wherein the timing adjustment unit adjusts the timing of the phase of the excitation signal so that the magnitude of the vector becomes an extreme value. The signal generator includes a reference signal generator that generates a reference signal, a sampling signal generator that generates the sampling signal based on the reference signal, and an excitation signal generator that generates the excitation signal based on the reference signal The angle detection apparatus according to claim 2, wherein the timing adjustment unit performs the timing adjustment by correcting a phase from the timing of the reference signal. The excitation signal generation unit includes a rectangular wave pulse generation unit that generates a rectangular wave pulse from the reference signal, an amplitude adjustment unit that adjusts the amplitude of the rectangular wave pulse, and a fundamental wave component of the rectangular wave pulse whose amplitude has been adjusted. The angle detection apparatus according to claim 4, further comprising: a low-pass filter that extracts the extracted signal and outputs the extracted signal as the excitation signal. The magnitude of the vector is calculated based on a sum of squares of an output value of the first AD converter and an output value of the second AD converter. The angle detection device according to any one of the above.

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