JP2012127829A - Resolver/digital converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resolver/digital converter that can compensate time delay caused by a processing time.SOLUTION: In a resolver/digital converter 10, when sensor values S1 and S2 output from a rotation position sensor are input in rotation position calculation means 11, the rotation position calculation means 11 performs processing for determining a rotation position on the sensor values S1 and S2 with a prescribed processing time ΔT and outputs the processing result as a first rotation position θcalc. Rotation position correction means 12 determines a delay value θdelay1 in which the first rotation position θcalc is delayed by delay time ΔT1 which is the processing time ΔT or less, determines a difference Δθ1 between the first rotation position θcalc and the delay value θdelay1, determines a second rotation position θcomp by adding a result obtained by multiplying the difference Δθ1 by a first correction factor m1 which is equal to a ratio of the processing time ΔT, to the delay time ΔT1 to the first rotation position θcalc and outputs the second rotation position θcomp as the rotation position.

Description

  Embodiments described herein relate generally to a resolver / digital converter.

  A synchronous motor (hereinafter simply referred to as a motor) that rotates a rotor by a rotating magnetic field detects the position (angle) of the rotor, and an armature winding provided on the outer periphery of the rotor based on the detected position. It is driven by controlling the current flowing through the line.

  The position of the rotor necessary for control is detected by a rotational position sensor (resolver) attached to the rotating shaft of the motor. A resolver is a sensor that converts the position of a rotor into an electrical signal, which basically has the same structure as a motor, detects the position of a rotating rotor, and outputs an analog signal corresponding to the position of the rotor.

  A resolver / digital converter is an apparatus that converts an analog signal output from a resolver into a digital signal, performs various processes, and calculates a rotational position.

  A drive signal for controlling the rotating magnetic field is generated based on the output of the resolver / digital converter, and an inverter that drives a predetermined alternating current to each phase of the armature winding at a predetermined timing is driven. As a result, a rotating magnetic field is generated and the rotor rotates.

  The processing performed by the resolver / digital converter includes various processing such as analog-digital conversion, digital signal synchronous detection, proportional integration (PI) control, addition / subtraction, multiplication, integration, and sine / cosine wave generation. . These processes require a finite time ΔT.

  The value of the digital signal calculated by the resolver / digital converter at time T is the value of the analog output signal output by the resolver at time T−ΔT. As a result, there is a problem that a time delay caused by the processing time ΔT occurs between the analog output signal output from the resolver and the digital signal value calculated by the resolver / digital converter.

  When the rotational speed of the motor increases, this time delay cannot be ignored, and there is a problem that stable rotational speed control cannot be performed.

JP 2000-88507 A

  The present invention provides a resolver / digital converter capable of compensating for a time delay due to processing time.

  According to one embodiment, in the resolver / digital converter, when the rotational position calculation means receives a sensor value output from a rotational position sensor that detects the rotational position of the rotor included in the electric motor, a predetermined value is input. Processing time is required, processing for obtaining the rotational position is performed on the sensor value, and the processing result is output as the first rotational position. The rotational position correcting means obtains a delay value obtained by delaying the first rotational position by a delay time equal to or shorter than the processing time, obtains a difference between the first rotational position and the delay value, and adds the difference between the processing time and the processing time. A result obtained by multiplying a first correction coefficient equal to the delay time ratio is added to the first rotational position to obtain a second rotational position, and the second rotational position is output as the rotational position.

1 is a block diagram showing a resolver / digital converter according to Embodiment 1. FIG. FIG. 3 is a circuit diagram illustrating a delay circuit according to the first embodiment. FIG. 6 is a diagram for explaining the operation of the rotational position correcting unit according to the first embodiment. 5 is a flowchart showing the operation of the rotational position correcting unit according to the first embodiment. FIG. 3 is a block diagram illustrating a rotational position correction unit according to the first embodiment. FIG. 3 is a block diagram showing another rotational position correction unit according to the first embodiment. FIG. 6 is a block diagram illustrating a rotational position correcting unit according to the second embodiment. FIG. 6 is a circuit diagram illustrating a delay circuit according to a second embodiment. FIG. 10 is a diagram for explaining the operation of the rotational position correction unit according to the second embodiment. FIG. 10 is a diagram for explaining another operation of the rotational position correcting unit according to the second embodiment. FIG. 9 is a block diagram illustrating a resolver / digital converter according to a third embodiment. FIG. 10 is a block diagram illustrating a rotational position correcting unit according to a fourth embodiment. FIG. 6 is a circuit diagram illustrating a delay circuit according to a fourth embodiment. FIG. 10 is a diagram for explaining an operation of a rotational position correction unit according to the fourth embodiment. FIG. 10 is a circuit diagram illustrating a delay circuit according to a fifth embodiment.

  Embodiments of the present invention will be described below with reference to the drawings.

  A resolver / digital converter according to this embodiment will be described with reference to FIGS. FIG. 1 is a block diagram showing the configuration of the resolver / digital converter of this embodiment, and FIG. 2 is a circuit diagram showing a delay circuit.

  As shown in FIG. 1, the resolver / digital converter 10 of this embodiment includes a rotational position calculation unit 11 and a rotational position correction unit 12.

  The rotational position calculation means 11 converts the sensor values S1 = sinτ · sinφ and S2 = sinτ · cosφ input from a resolver (not shown) into digital values, and performs various processes to calculate the rotational position (rotation angle). Then, the first rotation position θcalc is output.

  A finite processing time ΔT is required from when the sensor values S1 and S2 are input to the rotational position calculating unit 11 to when the first rotational position θcalc is output from the rotational position calculating unit 11.

  The first rotational position θcalc output by the rotational position calculation means 11 at time T is a value calculated based on the sensor values S1 and S2 output by the resolver at time T−ΔT. As a result, when the sensor values S1 and S2 output by the resolver change between the time T-ΔT and the time T, the first rotational position θcalc output by the rotational position calculation unit 11 at the time T is calculated by the resolver at the time T. It is different from the sensor values S1 and S2 being output.

  The rotational position correcting means 12 performs a process for compensating for a time delay caused by the processing time ΔT on the first rotational position θcalc input from the rotational position calculating means 11, and the compensated first rotational position θcalc is subjected to the second rotation. Output as position θcomp.

  The resolver / digital converter 10 includes various digital signal processing circuits and operates in synchronization with a clock signal having a period Ts. The rotational position calculation means 11 executes a process for obtaining the rotational position in synchronization with the clock signal, and the rotational position correction means 12 executes a process for compensating for the time delay in synchronization with the clock signal.

  The configuration and operation of the rotational position calculation means 11 are well known, but will be briefly described below. In the rotational position calculation means 11, the excitation signal generation circuit 13 generates an excitation signal sin τ and supplies the excitation signal sin τ to the excitation side winding (rotor) of the resolver and a detection circuit described later. Here, τ is the excitation angle of the excitation signal.

  The analog / digital converter (AD converter) 14 AD-converts the output signal S1 on the sign side of the output side winding (stator) of the resolver. The AD converter 15 AD converts the output signal S2 on the cosine side of the output side winding of the resolver. Here, φ indicates the rotational position of the resolver shaft.

  The AD converters 14 and 15 are, for example, 12-bit successive approximation AD converters, and AD converters having a sampling rate faster than the clock cycle Ts are suitable.

  The multiplication circuit 16 multiplies the output of the AD converter 14 and the output of the cos θ calculation circuit 17 and outputs a value of sin τ · sin φ · cos θ. The multiplication circuit 18 multiplies the output of the AD converter 15 and the output of the sin θ calculation circuit 19 and outputs a value of sin τ · cos φ · sin θ.

  The subtracting circuit 20 subtracts the output of the multiplying circuit 18 from the output of the multiplying circuit 16 and outputs a value of sinτ · sinφ · cosθ−sinτ · cosφ · sinθ = sinτ · sin (θ−φ).

The detection circuit 21 performs phase detection by multiplying the output of the subtraction circuit 20 by the excitation signal sinτ, and outputs a value of sin ² τ · sin (θ−φ).

The angular velocity calculation unit 22 is a PI (proportional integration) control circuit that performs a proportional integration operation on an input. The angular velocity calculation unit 22 performs a proportional integration operation on sin ² τ · sin (θ−φ), and determines the value of the angular velocity ω so that sin (θ−φ) = 0, that is, θ−φ = 0. .

  The integrating circuit 27 integrates the angular velocity ω output from the angular velocity calculating unit 22 to obtain the output angle θ. Since the output angle θ is controlled so that θ−φ = 0 with respect to the resolver angle φ, θ = φ. The rotational position calculation means 11 outputs this θ as the rotational position of the motor. This θ is the first rotation position θcalc.

  The cos θ calculation circuit 17 calculates a value of cos θ with respect to the angle θ and outputs the value to the multiplication circuit 16. The sin θ calculation circuit 19 calculates a value of sin θ with respect to the angle θ and outputs the value to the multiplication circuit 18.

  The processing time ΔT described above includes the AD conversion time of the AD converters 14 and 15, the calculation time from the multiplication circuit 16 to the integration circuit 27, and the phase delay of the signals in the angular velocity calculation unit 22 and the integration circuit 27. include.

  The processing time ΔT depends on the circuit configuration of the rotational position calculation means 11 and the clock frequency (1 / Ts), but is estimated to be about 3 to 4 clocks, for example. The processing time ΔT can be obtained by several methods.

  When the circuit configuration is finalized, it can be estimated in advance by simulation. The actual rotational position of the motor can be detected by an optical encoder or the like and compared with the first rotational position θcalc.

  Further, by making the delay circuit 31 have the same configuration as that of the rotational position calculating means 11, the rotational position calculating means 11 of the main body can be measured dynamically during operation. In this case, since AD conversion cannot be performed, another delay circuit that provides the same delay as the AD converters 14 and 15 is prepared. During this delay time, sinτ · sinθcalc and sinτ · cosθcalc are calculated.

  For example, assume that the clock frequency is 250 kHz (Ts = 4 μs) and the motor rotation speed is 240000 rpm. Since the time required for one rotation of the motor is 250 μs, the motor rotates 360 ° × 4 μs / 250 μs = 5.76 ° during one clock. When the processing time ΔT is 3 to 4 clocks, the motor advances from 17 ° to 23 ° during that time.

  Here, it is assumed that the rotation speed of the motor is constant and the processing time ΔT is equal to an integral multiple of the clock cycle Ts, for example, three times (ΔT = 3Ts).

  In the rotational position correcting means 12, the delay circuit 31 outputs a delay value θdelay1 obtained by delaying the first rotational position θcalc by a delay time ΔT1 equal to the processing time ΔT.

  The subtraction circuit 32 subtracts the delay value θdelay1 from the first rotational position θcalc and outputs a difference Δθ1.

  The correction coefficient multiplication circuit 33 multiplies the difference Δθ1 by a first correction coefficient m1 equal to the ratio ΔT / ΔT1 of the processing time ΔT and the delay time ΔT1. Here, since the processing time ΔT is equal to the delay time ΔT1, the first correction coefficient m1 is 1.

  The adder circuit 34 adds the multiplication result m1 · Δθ to the first rotational position θcalc to obtain the second rotational position θcomp compensated for the time delay due to the processing time ΔT, and uses the second rotational position θcomp to rotate the resolver. Output as position.

  FIG. 2 is a circuit diagram showing the delay circuit 31. As shown in FIG. 2, the delay circuit 31 is constituted by a four-stage register 35, and is a delay circuit that gives a delay of three times the clock cycle Ts to the first rotation position θcalc. The register 35 is a flip-flop, and passes the first rotation position θcalc in synchronization with the clock signal Ts.

  The resolver / digital converter 10 described above is configured to compensate for a time delay caused by the processing time ΔT required from the input of the sensor values S1 and S2 to the output of the first rotational position θcalc. .

  Next, the operation of the rotational position correcting unit 12 will be described. FIG. 3 is a diagram for explaining the operation of the rotational position correcting means 12. In FIG. 3, the horizontal axis represents elapsed time, and the vertical axis represents the rotational position of the motor. A solid line 41 indicates the actual rotational position θ of the motor. A broken line 42 indicates the first rotation position θcalc.

  As shown in FIG. 3, the rotational speed of the motor is constant, and the rotational position θ changes linearly with respect to time, and returns to the original position after one revolution. It is assumed that the first rotation position θcalc follows the rotation position θ with a delay of the processing time ΔT.

  At time tn, the delay circuit 31 outputs the first rotational position θcalc (n−1) at time tn−1 as a delay value θdelay1 obtained by delaying the first rotational position θcalc (n) by the delay time ΔT1.

  The subtraction circuit 32 subtracts θdelay1 from θcalc (n), and outputs the difference Δθ1 = θcalc (n) −θdelay1 = θcalc (n) −θcalc (n−1).

  Since the first correction coefficient m1 = 1, the correction coefficient multiplication circuit 33 outputs the difference Δθ1 as it is. The adder circuit 34 adds the difference Δθ1 to the first rotational position θcalc (n) and outputs the second rotational position θcomp (n) = θcalc (n) + Δθ1.

  As a result, it is possible to obtain a second rotational position θcomp (n) equal to the actual rotational position θ (n) of the motor.

  As long as the rotational speed of the motor is constant, Δθ1 is constant. However, when the motor has just made one revolution, that is, when the time tn is greater than the time T required for one revolution and the time tn−1 is smaller than the time T, the apparent difference Δθ1 becomes negative.

  FIG. 4 is a flowchart showing processing when the apparent difference Δθ1 becomes negative. The difference Δθ1 is allowed only in a range of ± 180 ° so that the motor can be handled in the reverse direction.

  As shown in FIG. 4, a difference Δθ1 is obtained (step S01), and it is determined whether or not the difference Δθ1 is smaller than −180 ° (step S02).

  When the difference Δθ1 is smaller than −180 ° (Yes in step S02), 360 ° is added to the difference Δθ1 (step S03), and the second rotational position θcomp is obtained (step S04). If the difference Δθ1 is greater than 180 ° (No in step S02), the process proceeds to step S05.

  Next, it is determined whether or not the difference Δθ1 is greater than 180 ° (step S05). If the difference Δθ1 is greater than 180 ° (Yes in step S05), 360 ° is subtracted from the difference Δθ1 (step S06) to obtain the second rotational position θcomp (step S06). If the difference Δθ1 is greater than 180 ° (No in step S05), the process proceeds to step S04.

  As described above, in the resolver / digital converter 10 of the present embodiment, the rotational position correcting unit 12 obtains the delay value θdelay1 obtained by delaying the first rotational position θcalc by the delay time ΔT1 equal to the processing time ΔT, The difference Δθ1 between the first rotation position θcalc and the delay value θdelay1 is obtained, and the difference Δθ1 is added to the first rotation position θcalc to obtain the second rotation position θcomp.

  As a result, it is possible to compensate for the time delay due to the processing time ΔT required from the input of the sensor values S1 and S2 to the output of the first rotational position θcalc. Therefore, a resolver / digital converter capable of compensating for the time delay due to the processing time can be obtained.

  Although the case where the processing time ΔT is equal to an integer multiple of the clock cycle Ts has been described here, the processing time may be different from an integer multiple of the clock cycle Ts.

  The phase delay of the signals in the angular velocity calculation unit 22 and the integration circuit 27 depends on the rotation speed of the motor. As a result, the processing time ΔT is not constant and changes according to the number of rotations of the motor.

  In the initial setting, even when the condition that the processing time ΔT is an integral multiple of the clock cycle Ts is satisfied, the condition is not satisfied when the number of rotations of the motor is greatly changed.

  In this case, as shown in FIG. 5, when the processing time is expressed as ΔT = ΔT1 + δ, the first correction coefficient m1 = 1 + δ / ΔT may be set. Here, δ is larger than 0 and smaller than Ts.

  Moreover, although the rotation position correction | amendment means 12 demonstrated the case where it performed by hardware by an application specific integrated circuit (ASIC: Application Specific Integrated Circuit), you may make it perform a series of correction processes by software by CPU. Absent.

  FIG. 6 is a block diagram showing rotational position correction means executed by software by the CPU. As shown in FIG. 6, in the rotational position correcting means 50, the I / O interface 51 takes in the first rotational position θcalc output from the rotational position calculating means 11 in synchronization with the clock cycle Ts, and CPU (Central Processing Unit) ) 52.

  The CPU 52 stores the first rotation position θcalc in a RAM (Random Access Memory) 53, causes the counter 54 to measure the delay time ΔT, and obtains a delay value θdelay1 obtained by delaying the first rotation position θcalc by the delay time ΔT. .

  Next, the delay value θdelay1 is subtracted from the first rotational position θcalc to obtain the difference Δθ, the difference Δθ is multiplied by the first correction coefficient m1, and the multiplication result is added to the first rotational position θcalc to obtain the second rotational position θcomp. Ask for.

  The I / O interface 55 outputs the obtained second rotational position θcomp to the outside. A ROM (Read Only Memory) 56 stores a program for controlling the operation of the CPU 52, a calculation algorithm, various initial values, and the like.

  A resolver / digital converter according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a block diagram showing the rotational position correcting means of this embodiment, and FIG. 8 is a circuit diagram showing a delay circuit.

  In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof will be omitted, and different portions will be described. This embodiment is different from the first embodiment in that the delay time is shorter than the processing time.

  That is, as shown in FIG. 7, in the rotational position correcting means 60 of this embodiment, the delay time ΔT2 is shorter than the processing time ΔT, for example, ΔT2 = Ts. The delay circuit 61 outputs a delay value θdelay2 obtained by delaying the first rotational position θcalc by the delay time ΔT2.

  The subtraction circuit 32 subtracts the delay value θdelay2 from the first rotation position θcalc and outputs a difference Δθ2.

  The correction coefficient multiplication circuit 33 multiplies the difference Δθ2 by a first correction coefficient m1 equal to the ratio ΔT / ΔT2 of the processing time ΔT and the delay time ΔT2. Here, since the processing time ΔT = 3Ts and the delay time ΔT2 = Ts, the first correction coefficient m1 is 3.

  The adder circuit 34 adds the multiplication result m1 · Δθ2 to the first rotational position θcalc to obtain the second rotational position θcomp compensated for the time delay due to the processing time ΔT, and uses the second rotational position θcomp as the rotation of the resolver. Output as position.

  FIG. 8 is a circuit diagram showing the delay circuit 61. As shown in FIG. 8, the delay circuit 61 is composed of a two-stage register 35, and is a delay circuit that gives a delay equal to the clock cycle Ts to the first rotation position θcalc.

  Next, the operation of the rotational position correcting means 60 will be described. FIG. 9 is a diagram for explaining the operation of the rotational position correcting means 60.

  As shown in FIG. 9, at time tn, the delay circuit 61 sets the first rotation position θcalc (n) at time tn−1 / 3 as a delay value θdelay2 obtained by delaying the first rotation position θcalc (n) by the delay time ΔT2. -1/3) is output. The subtraction circuit 32 subtracts θdelay2 from θcalc (n) and outputs a difference Δθ2 = θcalc (n) −θdelay2 = θcalc (n) −θcalc (n−1 / 3).

  Since the first correction coefficient m1 = 3, the correction coefficient multiplication circuit 33 multiplies the difference Δθ2 by m1 and outputs m1Δθ2. The adder circuit 34 adds the difference Δθ2 to the first rotational position θcalc (n) and outputs the second rotational position θcomp (n) = θcalc (n) + m1Δθ2.

  As a result, it is possible to obtain a second rotational position θcomp (n) equal to the actual rotational position θ (n) of the motor. The second rotational position θcomp (n) is equal to the second rotational position θcomp (n) shown in the first embodiment as long as the rotational speed of the motor is constant.

  Since the delay circuit 61 requires fewer registers 35 than the delay circuit 31, the circuit scale of the rotational position correction unit 60 can be made smaller than the circuit scale of the rotational position correction unit 12.

  FIG. 10 is a view for explaining the operation of the rotational position correcting means 60 when the rotational speed of the motor is changed in the middle, in comparison with the rotational position correcting means 12. In FIG. 10, a solid line 71 indicates the actual rotational position θ of the motor after the rotation speed of the motor is changed. A broken line 72 indicates the first rotation position θcalc after the rotation speed of the motor is changed.

  As shown in FIG. 10, it is assumed that the rotation speed of the motor increases between time tn-2 and time tn-1. Thus, the actual rotational position θ of the motor is represented by solid lines 41 and 71 that are bent between time tn−2 and time tn−1. The first rotational position θcalc is represented by broken lines 42 and 72 that are bent between the time tn−1 and the time tn with a delay of the processing time ΔT.

  First, the operation of the rotational position correction unit 12 will be described. As described above, the rotational position correcting unit 12 outputs the second rotational position θcomp (n) = θcalc (n) + Δθ1 indicated by a black circle. Since this second rotational position θcomp (n) is smaller than the actual rotational position θ (n) of the motor, an error has occurred. This is because the delay value θdelay1 = θcalc (n−1) is a value before the number of rotations of the motor increases.

  On the other hand, as described above, the rotational position correcting means 60 outputs the second rotational position θcomp (n) = θcalc (n) + 3Δθ2 indicated by a white circle. The second rotational position θcomp (n) is equal to the actual rotational position θ (n) of the motor, and no error has occurred. This is because the delay value θdelay2 = θcalc (n−1 / 3) is a value after the number of rotations of the motor is increased.

  The rotational position correcting means 60 can respond faster than the rotational position correcting means 12 to the increase in the motor rotational speed. As a result, it is possible to more accurately compensate for the time delay caused by the processing time ΔT. The same applies to the case where the rotational speed of the motor decreases, and the description thereof is omitted.

  As described above, in the resolver / digital converter of this embodiment, the rotational position correcting means 60 sets the delay time ΔT2 to be shorter than the processing time ΔT and the first correction coefficient to be larger than 1. As a result, the delay circuit 61 requires fewer registers 35 than the delay circuit 31 and has the advantage that the circuit scale of the rotational position correction means 60 can be reduced.

  Furthermore, since the rotational position correction means 60 responds faster to the increase / decrease in the motor rotational speed than the rotational position correction means 12, there is an advantage that the time delay caused by the processing time ΔT can be more accurately compensated. This configuration is suitable when the number of rotations of the motor is increased or decreased in a complicated manner.

  Although the case where the delay time ΔT2 = Ts has been described here, ΔT2 = 2Ts may be used. In that case, the first correction coefficient m1 is 1.5. The response of the rotational position correcting means 60 can be adjusted according to the delay time ΔT2.

  A resolver / digital converter according to a third embodiment of the present invention will be described with reference to FIG. FIG. 11 is a block diagram showing the resolver / digital converter of this embodiment.

  In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof will be omitted, and different portions will be described. The difference between the present embodiment and the first embodiment is that the delay due to the wiring connecting the resolver and the rotational position calculating means is compensated.

  That is, as shown in FIG. 11, the resolver 81 attached to the motor 80 and the rotational position calculation means 11 are connected by a pair of wiring cables 82. The sensor values S1 and S2 output from the resolver 81 propagate through the wiring cable 82 and are input to the rotational position calculation unit 11.

  The second rotational position θcomp output from the rotational position correction means 12 is fed back to the motor control circuit 83. The motor control circuit 83 includes an inverter circuit that drives the motor 80, a control signal generation circuit that controls the inverter, and the like, and controls the rotational speed of the motor 80.

  The wiring cable 82 has a propagation time ΔTL corresponding to the cable length L. The propagation time ΔTL of the wiring cable 82 can be obtained based on the cable length L and the characteristic impedance.

  When the propagation time ΔTL cannot be ignored in the feedback control of the rotation speed of the motor 80, such as when the rotation speed of the motor 80 is high or when the wiring cable 82 is long, it is necessary to compensate for the time delay due to the propagation time ΔTL. is there.

  For this purpose, the rotational position correcting means 12 may multiply the difference Δθ1 by the second correction coefficient m2 for compensating for the time delay caused by the propagation time ΔTL and add it to the first rotational position θcalc.

  The second correction coefficient m2 is represented by a ratio (ΔTL / ΔT1) between the propagation time ΔTL and the delay time ΔT1. The total correction coefficient m is the sum of the first correction coefficient m1 and the second correction coefficient m2, and is expressed by the following equation.

m = (ΔT + ΔTL) / ΔT1 = ΔT / ΔT1 + ΔTL / ΔT1 = m1 + m2 (1)
As described above, in the resolver / digital converter of the present embodiment, the time delay caused by the propagation time ΔTL caused by the wiring cable 82 connecting the resolver 81 and the rotational position calculation means 11 is compensated by the second correction coefficient m2. ing.

  There is an advantage that the influence of the propagation time ΔTL that cannot be ignored in the feedback control of the rotational speed of the motor 80 is obtained, for example, when the rotational speed of the motor 80 is high or the wiring cable 82 is long.

  Needless to say, this embodiment can be similarly applied to the resolver / digital converter described in the second embodiment.

  A resolver / digital converter according to Embodiment 4 of the present invention will be described with reference to FIGS. FIG. 12 is a block diagram showing the rotational position correcting means of this embodiment, and FIG. 13 is a circuit diagram showing a delay circuit.

  In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof will be omitted, and different portions will be described. This embodiment is different from the first embodiment in that it has a plurality of delay times.

  That is, as shown in FIG. 12, in the resolver / digital converter of this embodiment, the rotational position correcting means 90 includes a delay circuit 92 having an average delay circuit 91 having a delay time ΔT31, a delay circuit 93 having a delay time ΔT32, The delay circuit 94 includes a delay time ΔT33 and an average circuit 95.

  The delay circuit 92 outputs a delay value θdelay31 obtained by delaying the first rotational position θcalc by a delay time ΔT31. The delay circuit 93 outputs a delay value obtained by delaying the first rotational position θcalc by the delay time ΔT32. The delay circuit 94 outputs a delay value θdelay33 obtained by delaying the first rotational position θcalc by a delay time ΔT33.

  The average circuit 95 calculates an average value of the delay value θdelay 31, the delay value θdelay32, and the delay value θdelay33, and outputs the obtained average value as the average delay value θdelay3.

  That is, the average delay circuit 91 obtains an average delay value θdelay3 obtained by delaying the first rotational position θcalc by the average delay time ΔT3. The average delay time ΔT3 and the average delay value θdelay3 are expressed by the following equations.

ΔT3 = (ΔT31 + ΔT32 + ΔT33) / 3 (2)
θdelay3 = (θdelay31 + θdelay32 + θdelay33) / 3 (3)
The subtracter 32 subtracts the average delay value θdelay3 from the first rotational position θcalc and outputs an average difference Δθ3. The correction coefficient multiplication circuit 33 multiplies the average difference Δθ3 by the first correction coefficient m1, using the ratio (ΔT / ΔT3) of the processing time ΔT and the average delay time ΔT3 as the first correction coefficient m1, and outputs the multiplication result m1 · Δθ3. To do. The adder 34 adds the multiplication result m1 · Δθ3 to the first rotation position θcalc, and outputs the addition result as the second rotation position θcomp.

  For example, if the delay times ΔT31, ΔT32, and ΔT33 are ΔT31 = Ts, ΔT32 = 2Ts, and ΔT33 = 3Ts, the average delay time ΔT3 = 2Ts and the first correction coefficient m1 = 1.5.

  As shown in FIG. 13, the delay circuits 92, 93, 94 are realized by a four-stage register 35 that outputs the first rotational position θcalc in synchronization with the clock signal. The outputs of the second to fourth stage registers correspond to the outputs of the delay circuits 92, 93, and 94.

  Next, the operation of the rotational position correction means 90 will be described. FIG. 14 is a diagram for explaining the operation of the rotational position correcting means 90.

  As shown in FIG. 14, at time tn, the first rotational position θcalc (n−1 / 3) at time tn−1 / 3 is defined as a delay value θdelay31 obtained by delaying the first rotational position θcalc (n) by the delay time ΔT31. Is required. The first rotation position θcalc (n−2 / 3) at time tn−2 / 3 is obtained as a delay value θdelay32 obtained by delaying the first rotation position θcalc (n) by the delay time ΔT32. The first rotation position θcalc (n−1) at time tn−1 is obtained as a delay value θdelay33 obtained by delaying the first rotation position θcalc (n) by the delay time ΔT33.

  Further, an average delay value θdelay3 of the delay value θdelay31, the delay value θdelay32, and the delay value θdelay33 is obtained. The average delay value θdelay3 is also a moving average value of the delay value θdelay31, the delay value θdelay32, and the delay value θdelay33.

  An average difference Δθ3 between the first rotational position θcalc (n) and the average delay value θdelay3 is obtained, and the average difference Δθ3 is multiplied by the first correction coefficient m1. The multiplication result m1 · Δθ3 is added to the first rotational position θcalc (n) to obtain the second rotational position θcomp.

  The rotational position correcting means 90 has a response characteristic intermediate between the response characteristics of the rotational position correcting means 12 described in the first embodiment and the response characteristics of the rotational position correcting means 60 described in the second embodiment. It is possible to provide responsiveness to increase / decrease in motor rotation speed and resistance to noise.

  As long as the rotation speed of the motor is constant, the second rotational position θcomp of the present embodiment shows a value equal to the second rotational position θcomp of the first and second embodiments.

  As described above, in the resolver / digital converter of this embodiment, the rotational position correcting means 90 includes the average delay circuit 91 that outputs the average delay value θdelay3 obtained by delaying the first rotational position θcalc by the average delay time ΔT3. I have.

  As a result, the rotational position correction means 90 has a response characteristic that is intermediate between the response characteristics of the rotational position correction means 12 and 60, so that there is an advantage that it can have responsiveness to fluctuations in the motor rotation speed and resistance to noise.

  A resolver / digital converter according to Embodiment 5 of the present invention will be described with reference to FIG. FIG. 15 is a circuit diagram showing the delay circuit of this embodiment.

  In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof will be omitted, and different portions will be described. This embodiment is different from the first embodiment in that the delay time can be varied.

  That is, as shown in FIG. 15, the variable delay circuit 100 according to this embodiment includes a four-stage register 35 and a selection circuit 101 that selects one of the registers 35. The selection circuit 101 selects one of the second to fourth stage registers 35 based on the selection signal Vsl, and outputs the output of the selected register 35 as a delay value θdelay.

  When the fourth-stage register 35 is selected, the delay time ΔT4 = 3Ts, which is equal to the delay time ΔT1 of the delay circuit 31 shown in the first embodiment. When the second-stage register 35 is selected, the delay time ΔT4 = Ts, which is equal to the delay time ΔT2 of the delay circuit 61 shown in the second embodiment.

  Although the variable delay circuit 100 has a large circuit scale, the delay time can be varied in a programmable manner according to the purpose. For example, the configuration is suitable when it is desired to select an appropriate delay time when changing the rotational speed of the motor offline. The number of stages of the register 35 is not particularly limited.

  As described above, in the resolver / digital converter of the present embodiment, the rotational position correcting means includes the variable delay circuit 100, so that there is an advantage that the delay time can be varied in a programmable manner according to the purpose.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

The present invention can be configured as described in the following supplementary notes.
(Supplementary note 1) The resolver / digital converter according to claim 4, further comprising: an average circuit that obtains an average value of the outputs of the plurality of registers in the delay circuit and outputs the average value as the delay value.

(Additional remark 2) When the sensor value output from the rotational position sensor which detects the rotational position of the rotor contained in an electric motor is input, in order to require the predetermined processing time and to obtain the rotational position from the sensor value Performing the process, and outputting the processing result as a first rotational position;
A delay value obtained by delaying the first rotation position by a delay time equal to or less than the processing time is obtained, a difference between the first rotation position and the delay value is obtained, and the difference is a ratio of the processing time and the delay time. Adding a result obtained by multiplying an equal first correction coefficient to the first rotational position to obtain a second rotational position, and outputting the second rotational position as the rotational position;
A resolver / digital conversion method comprising:

(Supplementary Note 3) The rotation position is calculated from the sensor value output from the rotation position sensor that detects the rotation position of the rotor included in the electric motor, and the rotation position is output after the sensor value is input. A computer-readable recording medium recording a program for causing a computer to execute processing for compensating for a time delay due to processing time,
The process performs a process for obtaining the rotational position on the sensor value, and outputs the processing result as a first rotational position;
A delay value obtained by delaying the first rotation position by a delay time equal to or less than the processing time is obtained, a difference between the first rotation position and the delay value is obtained, and the difference is a ratio of the processing time and the delay time. Adding a result obtained by multiplying an equal first correction coefficient to the first rotational position to obtain a second rotational position, and outputting the second rotational position as the rotational position;
A computer-readable recording medium comprising:

DESCRIPTION OF SYMBOLS 10 Resolver / digital converter 11 Rotation position calculation means 12, 50, 60, 90 Rotation position correction means 20, 32 Subtraction circuit 22 Angular velocity calculation parts 31, 61, 92, 93, 94 Delay circuit 33 Correction coefficient multiplication circuit 34 Addition circuit 35 Register 80 Motor 81 Resolver 82 Wiring cable 83 Motor control circuit 91 Average delay circuit 95 Average circuit 100 Variable delay circuit 101 Selection circuit τ Excitation angle φ Resolver angle θ Output angle ΔT Processing time ΔT1, ΔT2, ΔT31, ΔT32, ΔT33 Delay time ΔTL Signal propagation delay time ΔT3 Average delay time θcalc First rotation position θdelay1, θdelay2 Delay value θdelay3 Average delay value Δθ1, Δθ2 Difference Δθ3 Average difference θcomp Second rotation position m1 First correction coefficient m2 Second correction coefficient Ts Clock period L Cable Long Vsl selection signal

Claims (5)

When a sensor value output from a rotational position sensor that detects the rotational position of the rotor included in the electric motor is input, a predetermined processing time is required and processing for obtaining the rotational position is performed on the sensor value. Rotation position calculation means for outputting the processing result as a first rotation position;
A delay value obtained by delaying the first rotation position by a delay time equal to or less than the processing time is obtained, a difference between the first rotation position and the delay value is obtained, and the difference is a ratio of the processing time and the delay time. A rotational position correcting means for obtaining a second rotational position by adding a result obtained by multiplying an equal first correction coefficient to the first rotational position, and outputting the second rotational position as the rotational position;
A resolver / digital converter.   The difference is multiplied by a second correction coefficient equal to the ratio of the propagation time required until the sensor value is input to the rotational position calculation means after the sensor value is output from the rotational position sensor and the delay time. The resolver / digital converter according to claim 1, wherein the result is further added to the first rotational position.   A plurality of delay values obtained by delaying the first rotational position by the delay time that is equal to or less than the processing time and different from each other are obtained, an average value of the plurality of delay values is set as the delay value, and 2. The resolver / digital converter according to claim 1, wherein an average value of delay times is the delay value. The rotational position calculating means and the rotational position correcting means operate in synchronization with a clock signal,
The rotational position correcting means includes
A delay circuit having a plurality of registers that pass through the first rotational position in synchronization with the clock signal;
A subtraction circuit for obtaining a difference between the first rotation position and the delay value;
A multiplication circuit that multiplies the difference by a first correction coefficient equal to a ratio of the processing time and the delay time;
An addition circuit for adding the multiplication result to the first rotation position;
The resolver / digital converter according to claim 1, comprising:   5. The selection circuit according to claim 4, wherein the delay circuit includes a selection circuit that selects any one of the plurality of stages of registers based on a selection signal and outputs an output of the selected register as the delay value. Resolver / digital converter.

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