Motor control device

Abstract

To provide a control device for a motor capable of accurately correcting a sensor signal even in a case where the motor is accelerated or decelerated.SOLUTION: A motor control device controls rotation of a brushless motor 20 on the basis of a sensor signal outputted from a position sensor which includes a plurality of Hall elements and detects a rotation position of the brushless motor. The motor control device comprises a time calculation section and a signal correction section. The time calculation section calculates a rotation time required for the brushless motor to be rotated at an electric angle of 360° on the basis of the sensor signal. The signal correction section corrects the sensor signal on the basis of the rotation time, which is calculated by the time calculation section, for a plurality of cycles in the past.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to controlling a motor. [Background technology]

[0002] The drive control device for a brushless motor described in Cited Document 1 measures and stores in advance the amount of positional deviation from a normal position of a rotational position detection sensor. The drive control device corrects the rotation sensor signal of the rotational position sensor in accordance with the stored amount of positional deviation, and controls the rotation speed of the brushless motor based on the corrected rotation sensor signal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-110363 A Summary of the Invention [Problem to be solved by the invention]

[0004] Errors in the sensor signal output from the position sensor are caused not only by deviations in the mounting position of the position sensor, but also by deviations in magnetic reading, etc. Therefore, even if the rotation sensor signal is corrected based on deviations in the mounting position of the position sensor as in the above-mentioned drive control device, errors may remain in the rotation sensor signal.

[0005] Therefore, a technology has been proposed in which pitch data is calculated based on 1° data, and the sensor signal is corrected based on the difference between the calculated pitch data and the reference pitch data of 60° electrical angle. The 1° data corresponds to the time it takes for the motor to rotate 1° electrical angle, and the pitch data corresponds to the electrical angle the motor rotates from one edge of the sensor signal to the next edge.

[0006] However, the pitch data is calculated based on 1° data from one electrical angle period before the point in time when the pitch data is calculated, so when the motor is accelerating or decelerating, the 1° data used to calculate the pitch data becomes larger or smaller than the true value, which may reduce the accuracy of correction of the sensor signal.

[0007] The present disclosure provides a motor control device that is capable of correcting a sensor signal with high accuracy even when the motor is accelerating or decelerating. [Means for solving the problem]

[0008] A motor control device (10) according to one aspect of the present disclosure controls rotation of a brushless motor (20) based on a sensor signal output from a position sensor (30) that includes multiple Hall elements (H1, H2, H3) and detects the rotational position of the brushless motor (20). The motor control device includes a time calculation unit (10) and a signal correction unit (10). The time calculation unit calculates the rotation time required for the brushless motor to rotate through 360° electrical angle based on the sensor signal. The signal correction unit corrects the sensor signal based on the rotation times for multiple past cycles calculated by the time calculation unit.

[0009] A motor control device according to one aspect of the present disclosure corrects a sensor signal based on a rotation time of multiple cycles. When the brushless motor is accelerating, the rotation time shortens as the cycle elapses, and when the motor is decelerating, the rotation time lengthens as the cycle elapses. That is, the rotation time of multiple cycles includes information on the acceleration or deceleration of the brushless motor. Therefore, by using the rotation time of multiple cycles, the sensor signal can be corrected with high accuracy even when the brushless motor is accelerating or decelerating. [Brief description of the drawings]

[0010] [Figure 1] 1 is a block diagram showing a configuration of a motor system according to a first embodiment. [Diagram 2]4A and 4B are diagrams illustrating a case where the detection position of the Hall element according to the first embodiment is normal and a case where there is an error. [Diagram 3] FIG. 4 is a diagram showing pitch data according to the first embodiment. [Figure 4] FIG. 4 is a diagram showing calculation of 1° data according to the first embodiment. [Diagram 5] FIG. 4 is a diagram showing an estimation of 1° data during acceleration of the motor according to the first embodiment. [Figure 6] FIG. 11 is a diagram showing an estimation of 1° data during acceleration of the motor according to the reference example. [Figure 7] FIG. 4 is a diagram showing an estimation of 1° data during deceleration of the motor according to the first embodiment. [Figure 8] FIG. 11 is a diagram showing an estimation of 1° data during deceleration of a motor according to a reference example. [Figure 9] FIG. 11 is a diagram showing an estimation of 1° data during acceleration of the motor according to the second embodiment. [Figure 10] FIG. 13 is a diagram showing estimation of a reference electrical angle timer according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. <1. First embodiment> <1-1. Configuration> The configuration of a motor system 100 according to this embodiment will be described with reference to Fig. 1. The motor system 100 comprises a motor 20, a position sensor 30, and a motor control device 10.

[0012] The motor 20 is a three-phase brushless motor. The motor 20 is a blower motor, and more specifically, a blower motor for an air conditioner of a vehicle. The position sensor 30 includes three Hall elements H1, H2, and H3, and outputs a sensor signal corresponding to the position of the rotor of the motor 20 to the motor control device 10. The Hall elements H1, H2, and H3 are arranged around the rotor at intervals of 120° electrical angle. Specifically, the Hall element H2 is arranged at a position 120° electrical angle away from the Hall element H1. The Hall element H3 is arranged at a position 120° electrical angle away from the Hall element H2.

[0013] Each of the Hall elements H1, H2, and H3 outputs a sensor signal corresponding to the position of the rotor to the motor control device 10. The output of each of the Hall elements H1, H2, and H3 rises or falls as the magnetic poles of the rotor change positions on the Hall element.

[0014] The motor control device 10 includes a three-phase drive circuit that drives the motor 20. The drive circuit is, for example, a full-bridge circuit including three switching elements arranged on the high side and three switching elements arranged on the low side. The motor control device 10 controls the on / off of each switching element of the drive circuit to sequentially pass current through the U-phase, V-phase, and W-phase coils.

[0015] The motor control device 10 detects the position of the rotor based on the sensor signals output from the Hall elements H1, H2, and H3, and determines the timing for energizing the coils of the U-phase, V-phase, and W-phase based on the detected rotor position.

[0016] As shown in Fig. 2, the sensor signals of the Hall elements H1, H2, and H3 alternate between up and down edges at intervals of 180 electrical degrees. Since the Hall elements H1, H2, and H3 are arranged at intervals of 120 electrical degrees, the timing of the up and down edges of the sensor signals is shifted. Specifically, the edge interval from the up edge of the sensor signal of the Hall element H1 to the down edge of the Hall element H2 is an electrical angle of 60 degrees, and the edge interval from the down edge of the Hall element H2 to the up edge of the Hall element H3 is an electrical angle of 60 degrees. Therefore, the edges of the sensor signals are input to the motor control device 10 at intervals of 60 electrical degrees.

[0017] The motor control device 10 detects the rotor position based on the edges of the sensor signal input every 60° electrical angle, and determines the timing to energize the coils of each phase. However, as shown in Fig. 2, the sensor signal may contain errors, causing the edge interval to deviate from the electrical angle of 60°. Deviations in edge intervals occur due to deviations in the mounting positions of the Hall elements H1, H2, and H3, deviations in magnetic reading by the Hall elements H1, H2, and H3, etc.

[0018] If the edge interval deviates from an electrical angle of 60°, the timing for energizing the coils of each phase deviates from the appropriate timing. This results in increased noise from the motor 20. For this reason, the motor control device 10 corrects the error in the sensor signal and determines the timing for energizing the coils of each phase based on the corrected sensor signal. The process for correcting the sensor signal will be described below.

[0019] <1-2. Correction processing> In this embodiment, the motor control device 10 has the functions of a time calculation unit, a first data calculation unit, a data estimation unit, and a signal correction unit, calculates pitch data, and corrects the sensor signal based on the difference between the calculated pitch data and a reference value. As shown in Fig. 3, the pitch data corresponds to the electrical angle through which the motor 20 rotates during a calculated period from one edge of the sensor signal to the next edge. The reference value is an electrical angle of 60°, and if the sensor signal does not contain an error, the pitch data will match the reference value.

[0020] The motor control device 10 counts up 1° data during the calculation period to calculate pitch data. The 1° data corresponds to the time required for the motor 20 to rotate through 1 electrical angle. That is, the motor control device 10 calculates the rotation time, which is the time required for the motor 20 to rotate once (i.e., an electrical angle of 360°), and divides the calculated rotation time by 360 to calculate the 1° data.

[0021] During the calculation period, the motor control device 10 uses a built-in timer of the motor control device 10 to count up by 1° each time the time indicated by 1° data elapses, thereby calculating the pitch data. Therefore, when calculating the pitch data, the motor control device 10 calculates the pitch data at the calculation time t n From the 1° data calculated in the previous period, the pitch data is calculated at the time t n 1° data at X n That is, the motor control device 10 estimates and uses the calculation time t n The rotation time calculated in the previous period is calculated at the time t n 1° data at X n In this embodiment, the period refers to an electrical angle period, and one period is the period during which the motor 20 rotates through an electrical angle of 360°.

[0022] Here, at the time t n-1 1° data at X n-1 At the calculation time t n 1° data at X n However, as shown in FIG. 4, when the motor 20 is accelerating, the 1° data decreases with the increase in the rotation speed. Therefore, as shown in FIG. 6, the 1° data X n-1 1° data X n In this case, the 1° data to be used is X n But the true 1° data X n will be greater than.

[0023] As a result, the motor control device 10 counts the pitch data as smaller than the true value. For example, when the true value of the pitch data is an electrical angle of 55°, the 1° data X n-1 1° data X n As a result, the pitch data is calculated to be an electrical angle of 50°. This causes the correction amount of the sensor signal to deviate from the true correction amount, reducing the correction accuracy of the sensor signal.

[0024] Also, when the motor 20 is decelerating, the 1° data increases in accordance with the decrease in the rotation speed. Therefore, as shown in FIG. n-1 1° data X n In this case, the 1° data to be used is X n But the true 1° data X n As a result, the motor control device 10 counts the pitch data to be larger than the true value. For example, when the true value of the pitch data is an electrical angle of 65°, the 1° data X n-1 1° data X n As a result, the pitch data is calculated to be an electrical angle of 70°. This causes the correction amount of the sensor signal to deviate from the true correction amount, reducing the correction accuracy of the sensor signal.

[0025] Therefore, the motor control device 10 corrects the sensor signal based on the rotation time of multiple past cycles. Specifically, the motor control device 10 calculates 1° data for multiple cycles from the rotation time of multiple past cycles, and calculates the slope ΔX of the 1° data for multiple cycles. In other words, the motor control device 10 calculates the rate of change of the 1° data from the 1° data for multiple cycles. Then, the motor control device 10 uses the slope ΔX to calculate the change rate of the 1° data at the calculation time t n 1° data at X n Estimate.

[0026] The rotation time for multiple periods is at least two rotation times, and preferably is calculated at the time t n At the time t one period before n-1 Rotation time T n-1 and t two periods ago n-2 Rotation time Tn-2 Includes.

[0027] In this embodiment, the motor control device 10 n-1 Rotation time T n-1 and time t n-2 Rotation time T n-2 From time t n-1 1° data at X n-1 and time t n-2 X in n-2 Then, the motor control device 10 calculates the slope ΔX=(X n-1 -X n-2 ) / Δt1 to calculate the slope ΔX. Δt1 is the time t n-2 From n-1 Then, the motor control device 10 determines the time until X n =X n-1 +ΔX×Δt2, calculate the time t n 1° data at X n Δt2 is estimated at time t n-1 From n It is time until.

[0028] The motor control device 10 calculates 1° data X based on the inclination ΔX. n By estimating the above, as shown in FIG. 5, at the time t n-1 1° data at X n-1 1° data smaller than X n In addition, as shown in FIG. 7, when the motor 20 is decelerating, at a time t n-1 1° data at X n-1 1° data greater than X n is estimated.

[0029] <1-3.Effects> According to the first embodiment described above in detail, the following effects are achieved. (1) The motor control device 10 corrects the sensor signal based on the rotation time for multiple cycles. When the motor 20 is accelerating, the rotation time shortens as the cycle passes, and when the motor 20 is decelerating, the rotation time lengthens as the cycle passes. That is, the rotation time for multiple cycles includes information on the acceleration or deceleration of the motor 20. Therefore, by using the rotation time for multiple cycles, the motor control device 10 can accurately correct the sensor signal even when the motor 20 is accelerating or decelerating.

[0030] (2) The motor control device 10 calculates the calculation time t from the gradient ΔX of the 1° data for multiple periods. n 1° data at X n By estimating the above, even if the motor 20 is accelerating or decelerating, the 1° data X n As a result, motor control device 10 can accurately correct the sensor signal even when motor 20 is accelerating or decelerating.

[0031] <2. Second embodiment> <2-1. Differences from the first embodiment> The second embodiment has a basic configuration similar to that of the first embodiment, and therefore differences will be described below. Note that the same reference numerals as those in the first embodiment indicate the same configuration, and the preceding description will be referred to.

[0032] In the first embodiment described above, the motor control device 10 calculates the slope ΔX from 1° data over multiple cycles. In contrast, the second embodiment differs from the first embodiment in that a regression line is calculated from 1° data over multiple cycles.

[0033] As shown in FIG. 9, the motor control device 10 calculates a regression line with time and 1° data as variables from the 1° data for multiple past cycles, and uses the calculated regression line to calculate the calculated time t n 1° data at X n The 1° data for multiple periods is 1° data for at least two periods, for example, at time t n-mFrom time t n-1 This is 1° data up to the point where m is an integer of 2 or more.

[0034] <2-2.Effects> According to the second embodiment described above in detail, in addition to the effect (1) of the first embodiment described above, the following effect is further achieved.

[0035] (3) The motor control device 10 calculates the calculated time t from a regression line based on 1° data for multiple periods. n 1° data at X n By estimating the above, even if the motor 20 is accelerating or decelerating, the 1° data X n As a result, motor control device 10 can accurately correct the sensor signal even when motor 20 is accelerating or decelerating.

[0036] <3. Third embodiment> <3-1. Differences from the first embodiment> The third embodiment has a basic configuration similar to that of the first embodiment, and therefore differences will be described below. Note that the same reference numerals as those in the first embodiment indicate the same configurations, and the preceding description will be referred to.

[0037] In the first embodiment described above, the motor control device 10 corrected the sensor signal based on the difference between the calculated pitch data and the reference value of an electrical angle of 60°. In contrast, the third embodiment differs from the first embodiment in that the motor control device 10 corrects the sensor signal based on the difference between a reference electrical angle timer and the reference value of an electrical angle of 360°. In this embodiment, the motor control device 10 has the functions of a time calculation unit, a time estimation unit, an electrical angle calculation unit, and a signal correction unit.

[0038] The reference electrical angle timer starts from a first time point and corresponds to the electrical angle by which the motor 20 has rotated. The first time point is the time point at which an up-edge or down-edge of a sensor signal output from a specific one of the three Hall elements H1, H2, and H3 is detected. In this embodiment, the first time point is the time point at which an up-edge of a sensor signal output from a specific one of the Hall elements is detected.

[0039] As shown in FIG. 10, the motor control device 10 calculates the elapsed time from the first point in time as a calculation point t n Rotation time T n The motor control device 10 calculates a reference electrical angle timer by multiplying the value obtained by dividing by 360°. The motor control device 10 corrects the sensor signal based on the difference between the reference electrical angle timer from the first time point to the second time point and the electrical angle of 360°. The second time point is the time point at which the up edge of the sensor signal output from one specific Hall element is detected after the first time point. If the first time point is the time point at which the down edge of the sensor signal output from one specific Hall element is detected, the second time point is the time point at which the down edge of the sensor signal output from one specific Hall element is detected after the first time point. If the sensor signal does not include an error, the reference electrical angle timer from the first time point to the second time point coincides with the electrical angle of 360°.

[0040] The motor control device 10 calculates the calculated time t based on the rotation time of multiple past cycles. n Rotation time T n Estimate the estimated rotation time T n The motor control device 10 preferably calculates the reference electrical angle timer based on the rotation time of at least two periods, at the calculation time t n At the time t one period before n-1 Rotation time T n-1 and t two periods ago n-2 Rotation time T n-2 From the above, the rotation time T n Estimate.

[0041] In this embodiment, the motor control device 10 n-1Rotation time T n-1 and time t n-2 Rotation time T n-2 From the above, the rotation time T n Specifically, the motor control device 10 estimates the rotation time T n =T n―1 -(T n―2 -T n―1 ) at time t n-1 and time t n-2 The change in rotation time ΔT (=T n―2 -T n―1 ) at time t n-1 Rotation time T n-1 In other words, the motor control device 10 calculates the slope (i.e., the rate of change) of the rotation time from the rotation times of multiple past periods, and estimates the rotation time Tn at the calculation time point t n Rotation time T n Estimate.

[0042] The motor control device 10 calculates a regression line with time and rotation time as variables from the rotation times of the past several cycles, and uses the calculated regression line to calculate the calculated time t n Rotation time T n may be estimated.

[0043] <3-2.Effects> According to the third embodiment described above in detail, in addition to the effect (1) of the first embodiment described above, the following effect is further achieved.

[0044] (4) The motor control device 10 calculates the calculated time t n Rotation time T n By estimating the rotation time T n As a result, motor control device 10 can accurately correct the sensor signal even when motor 20 is accelerating or decelerating.

[0045] <3. Other embodiments> Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be implemented in various modified forms.

[0046] (a) The motor control device 10 and the method thereof described in the present disclosure may be realized by a dedicated computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. Alternatively, the motor control device 10 and the method thereof described in the present disclosure may be realized by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the motor control device 10 and the method thereof described in the present disclosure may be realized by one or more dedicated computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. In addition, the computer program may be stored in a computer-readable non-transient tangible recording medium as instructions executed by a computer. The method for realizing the functions of each unit included in the motor control device 10 does not necessarily need to include software, and all of the functions may be realized using one or more hardware.

[0047] (b) Multiple functions possessed by one component in the above embodiments may be realized by multiple components, or one function possessed by one component may be realized by multiple components. Also, multiple functions possessed by multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Also, part of the configuration of the above embodiments may be omitted. Also, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments.

[0048] (c) In addition to the motor control device 10 described above, the present disclosure can be realized in various forms, such as a system including the motor control device 10 as a component, a program for causing a computer to function as the motor control device 10, a non-transient physical recording medium such as a semiconductor memory on which this program is recorded, and a motor control method. [Explanation of symbols]

[0049] 10...motor control device, 20...motor, 30...position sensor, 100...motor system, H1, H2, H3...Hall elements.

Claims

1. A motor control device (10) that controls rotation of a brushless motor (20) based on a sensor signal output from a position sensor (30) that includes a plurality of Hall elements (H1, H2, H3) and detects a rotational position of the brushless motor, a time calculation unit (10) that calculates a rotation time required for the brushless motor to rotate 360° electrical angle based on the sensor signal; and a signal correction unit (10) that corrects the sensor signal based on the rotation times of multiple past periods calculated by the time calculation unit. Motor control device.

2. a first data calculation unit (10) that divides each of the rotation times for the past multiple cycles calculated by the time calculation unit (10) by 360 to calculate 1° data that is a time required for the motor to rotate by 1 electrical angle for the past multiple cycles; a data estimation unit (10) that estimates the 1° data at the present time from the inclination of the 1° data for the past multiple periods calculated by the first data calculation unit; a second data calculation unit (10) that counts up the 1° data estimated by the data estimation unit during a period from an edge of the sensor signal to a next edge, and calculates pitch data corresponding to an electrical angle by which the brushless motor has rotated during the period, The signal correction unit (10) corrects the sensor signal based on a difference between the pitch data calculated by the second data calculation unit and a reference value. The motor control device according to claim 1 .

3. a first data calculation unit (10) that divides each of the rotation times for the past multiple cycles calculated by the time calculation unit (10) by 360 to calculate 1° data that is a time required for the brushless motor (20) to rotate an electrical angle of 1° for the past multiple cycles; a data estimation unit (10) that estimates the 1° data at the present time from a regression line based on the 1° data for the past multiple periods calculated by the first data calculation unit; a second data calculation unit (10) that counts up the 1° data estimated by the data estimation unit during a period from an edge of the sensor signal to a next edge, and calculates pitch data corresponding to an electrical angle by which the brushless motor (20) has rotated during the period, The signal correction unit (10) corrects the sensor signal based on a difference between the pitch data calculated by the second data calculation unit and a reference value. The motor control device according to claim 1 .

4. a time estimation unit (10) that estimates the current rotation time based on the rotation times of the past multiple cycles calculated by the time calculation unit (10); an electrical angle calculation unit (10) that calculates an electrical angle of rotation of the brushless motor (20) from a time from an up edge to a next up edge of the sensor signal output from one of the plurality of Hall elements (H1, H2, H3) or a time from a down edge to a next down edge of the sensor signal output from the one of the plurality of Hall elements (H1, H2, H3) and the rotation time estimated by the time estimation unit, in a period from the up edge to the next up edge or from the down edge to the next down edge; The signal correction unit (10) corrects the sensor signal based on a difference between the electrical angle calculated by the electrical angle calculation unit and 360°. The motor control device according to claim 1 .

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