Motor control device

Abstract

To provide a technology for correcting the rotational position of a rotor detected by a rotational sensor with high precision.SOLUTION: A phase difference detection unit 54 detects a phase difference between a generation timing of a detection signal of a rotation position of a rotor 14 of a brushless motor 10 and a generation timing of an induced voltage of stator coils 12U, 12V, 12W. A cycle detection unit 54 detects a signal cycle of the detection signal. An order determination unit 54 determines the order of the timing of occurrence of the detection signal and an induced voltage. A correction unit 54 corrects the timing of energizing a stator coil on the basis of a phase difference when the signal cycle of the detection signal is within a predetermined cycle and the detection signal is in the forward direction, which is ahead of the induced voltage, or in the reverse direction, which is behind the induced voltage, and corrects the timing of energizing a stator coil on the basis of a learning value of the correction learned in the past, when the signal cycle is within the predetermined cycle and includes both forward and reverse directions, or when the signal cycle is longer than the predetermined cycle.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a technique for controlling the rotation of a brushless motor. [Background technology]

[0002] 2. Description of the Related Art There is known a technique for controlling the rotation of a brushless motor by detecting the rotational position of a rotor of the brushless motor with a rotation sensor and controlling the supply of electricity to a stator coil based on the rotational position of the rotor.

[0003] However, the rotational position detected by the rotational sensor may vary due to an error in the mounting position of the rotational sensor or due to variations in the characteristics of the rotational sensor. In this case, the timing of energizing the stator coil, which is controlled based on the rotational position detected by the rotational sensor, is shifted, making it impossible to properly control the rotation of the brushless motor, resulting in increased noise and vibration.

[0004] Therefore, Patent Document 1 below proposes a technique for correcting the rotational position of the rotor detected by a rotation sensor based on the phase difference between a detection signal of the rotational position by the rotation sensor and an induced voltage generated in a stator coil.

[0005] The technology described in Patent Document 1 makes it possible to correct the rotational position of the rotor detected by the rotation sensor, regardless of whether the timing of the detection signal from the rotation sensor is forward, meaning that it is ahead of the timing of the induced voltage, or reverse, meaning that it is behind the timing of the induced voltage. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2017-169332 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, if the timing of generation of the detection signal from the rotation sensor and the timing of generation of the induced voltage are mixed in both forward and reverse order, it is not possible to determine whether the rotational position of the rotor detected by the rotation sensor should be corrected in accordance with the forward or reverse order.

[0008] Furthermore, if the signal period of the detection signal of the rotation sensor becomes longer than a predetermined period due to an abnormality in the brushless motor or the like, a counter that counts the time of the signal period, etc., in a microcomputer or the like may overflow. If the counter overflows, it is not possible to correct the rotation position of the rotor detected by the rotation sensor based on the phase difference between the detection signal of the rotation position and the induced voltage generated in the stator coil.

[0009] In the technology described in Patent Document 1, when the timing of generation of the detection signal of the rotation sensor and the timing of generation of the induced voltage are mixed in both forward and reverse order, or when the signal period of the detection signal becomes longer than a predetermined period, it is considered that the rotational position of the rotor is corrected by a fixed correction value.

[0010] However, as a result of detailed investigation by the inventors, it was found that the use of a fixed correction value results in a decrease in accuracy in correcting the rotational position of the rotor detected by the rotation sensor. One aspect of the present disclosure is to provide a technique for highly accurately correcting the rotational position of a rotor detected by a rotation sensor. [Means for solving the problem]

[0011] A motor control device (50) according to one embodiment of the present disclosure is a motor control device that controls the rotation of a brushless motor (10), and includes a phase difference detection unit (54, S410, S412), a period detection unit (54, S406), an order determination unit (54, S412), and a correction unit (54, S408, S420-S434).

[0012] The phase difference detection unit detects the phase difference between the generation timing of a detection signal of a rotation sensor (22) that detects the rotational position of a rotor (14) having magnetic poles and the generation timing of an induced voltage generated in the stator coils (12U, 12V, 12W) of the stator (12). The period detection unit detects the signal period of the detection signal. The order determination unit determines the order of the generation timing of the detection signal and the generation timing of the induced voltage.

[0013] The correction unit corrects the timing of current supply to the stator coil based on the phase difference detected by the phase difference detection unit when the signal period of the detection signal detected by the period detection unit is equal to or shorter than a predetermined period and the order determination unit determines that the detection signal is in forward order, that is, the timing of generation of the detection signal is ahead of the timing of generation of the induced voltage, or when the order determination unit determines that the detection signal is in reverse order, that is, the timing of generation of the detection signal is behind the timing of generation of the induced voltage, and corrects the timing of current supply to the stator coil based on a learning value learned in the past to correct the timing of current supply to the stator coil in the case of forward order or reverse order, when the signal period is equal to or shorter than the predetermined period and forward order and reverse order are mixed, or when the signal period is longer than the predetermined period.

[0014] According to this configuration, when the signal period of the detection signal is equal to or shorter than a predetermined period and contains a mixture of forward and reverse signals, or when the signal period is longer than the predetermined period, the timing of current flow to the stator coil is corrected based on a learned value learned in the past rather than a fixed correction value.

[0015] In this way, by correcting the energization timing to the stator coil using a learned value learned in the past rather than correcting it with a fixed value, the energization timing to the stator coil can be corrected with high accuracy. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a circuit diagram showing a configuration of a motor control device. [Diagram 2] 4 is a time chart showing a stator voltage, a comparator voltage, and a Hall sensor voltage. [Diagram 3] An enlarged view of the area line III in Figure 2. [Figure 4] 4 is a flowchart showing a motor control process. [Diagram 5] 6 is a time chart showing a case where the Hall sensor voltage and the comparator voltage are in the normal order. [Figure 6] 11 is a time chart showing a case where the Hall sensor voltage and the comparator voltage are in reverse order. [Figure 7] A time chart showing the cause of the reverse order. [Figure 8] A time chart when forward and reverse orders are mixed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. [1. Configuration] A brushless motor 10 shown in FIG. 1 is used as a blower motor for a vehicle air conditioner, and is rotationally driven by three-phase driving power having U-phase, V-phase, and W-phase.

[0018] The brushless motor 10 includes a stator 12 and a rotatably supported rotor 14. The stator 12 includes U-phase, V-phase, and W-phase stator coils 12U, 12V, and 12W, which are star-connected. The rotor 14 has six magnetic poles, with the magnetic poles changing every 60°.

[0019] The motor drive device 20 drives the brushless motor 10 by supplying drive power to each of the three-phase stator coils 12U, 12V, and 12W at energization timing set by a motor control device 50 described below. The motor drive device 20 includes a Hall sensor 22, a power supply stabilizing circuit 30, an inverter 40, a motor control device 50, and the like.

[0020] The Hall sensor 22 is installed in the motor drive device 20 to detect the magnetic pole position of the rotor 14, i.e., the rotational position of the rotor 14. The Hall sensor 22 is, for example, a Hall IC. The Hall IC includes a Hall element and a circuit for processing the output voltage of the Hall element.

[0021] The Hall sensor 22 includes three Hall sensors 22U, 22V, and 22W (not shown) corresponding to the three phases. The Hall sensors 22U, 22V, and 22W output pulse-like detection signals with a phase difference of 120° in response to the rotation of the rotor 14, for detecting the rotational position of the rotor 14.

[0022] The power supply stabilizing circuit 30 stabilizes the DC power supplied from the DC power supply 2 and supplies it to a downstream circuit. The power supply stabilizing circuit 30 includes a smoothing capacitor 32 and a choke coil 34. The smoothing capacitor 32 is connected to the positive power supply line and the negative power supply line of the DC power supply 2.

[0023] The choke coil 34 is disposed between the points where the two smoothing capacitors 32 are connected to the positive power supply line. The inverter 40 is a DC-AC conversion circuit. The inverter 40 generates three-phase driving power having a phase difference of 120° from the DC power supplied by the DC power source 2, and supplies the driving power to the brushless motor 10.

[0024] The inverter 40 includes three upper and lower arm circuits 42 corresponding to the three phases. Each of the upper and lower arm circuits 42 has two switching elements connected in series between a positive power supply line and a negative power supply line. In this embodiment, one n-channel MOSFET is used as the switching element constituting each of the upper and lower arms of the upper and lower arm circuit 42.

[0025] One end of U-phase stator coil 12U, V-phase stator coil 12V, and W-phase stator coil 12W are connected between two switching elements of each of upper and lower arm circuits 42 for the U, V, and W phases.

[0026] The switching elements of the upper and lower arm circuits 42 are switched at predetermined timings, whereby the driving power of each phase is supplied to the stator coils 12U, 12V, 12W of each phase.

[0027] The motor control device 50 sets the timing of energization of drive power supplied to each of the three-phase stator coils 12U, 12V, and 12W. The motor control device 50 includes a standby circuit 52, a drive timing generation unit 54, a control unit 56, an F / V converter 58, a PWM generation unit 60, an AND circuit 62, a protection circuit 64, and a comparator 66.

[0028] The standby circuit 52 supplies operating power to the components of the motor control device 50 in response to a command signal from the air conditioner ECU 4 . The drive timing generating section 54, the control section 56, and the F / V converter 58 receive the detection signal of the Hall sensor 22 described above.

[0029] The drive timing generation unit 54 detects the rotational position of the rotor 14 based on the three-phase detection signal output by the Hall sensor 22, and outputs to the control unit 56 a drive timing signal that sets the drive timing for passing current through the switching elements of each phase of the inverter 40.

[0030] The drive timing generating unit 54 also includes a period timer counter (not shown) that counts the period from one rising edge to the next rising edge of the detection signal of the Hall sensor 22 of the U phase, that is, the time of 360° electrical angle.

[0031] The drive timing generating unit 54 also includes a phase difference timer counter that counts the phase difference time from the rising edge of the detection signal of the Hall sensor 22 of the U phase to the rising edge of the induced voltage of the stator coil 12U.

[0032] The control unit 56 generates a drive control signal based on a speed command value from a speed setting unit (not shown), the rotational position of the rotor 14, and the drive timing set by the drive timing generation unit 54. The control unit 56 outputs the generated drive control signal directly to the switching on the upper arm side of each phase of the inverter 40, and outputs it to the switching elements on the lower arm side via an AND circuit 62.

[0033] If the drive timing signal is not output from the drive timing generating unit 54, the control unit 56 does not output a drive control signal to the inverter 40. In this case, the current supply to the stator coils 12U, 12V, and 12W is cut off, and the brushless motor 10 rotates idly.

[0034] The F / V converter 58 converts into a voltage a frequency corresponding to the rotation speed of the rotor 14, which is obtained based on the detection signal of the Hall sensor 22. The F / V converter 58 outputs the converted voltage to the PWM generating unit 60.

[0035] PWM generation unit 60 recognizes the rotation speed of rotor 14 based on the converted voltage input from F / V converter 58, and adjusts the duty ratio of the PWM control signal so that the rotation speed becomes the one set by the speed command value. By outputting this PWM control signal from PWM generation unit 60 to AND circuit 62, the on-time during which the switching element on the lower arm side is actually on is changed, and the drive power supplied to brushless motor 10 is adjusted. In this way, the rotation speed of brushless motor 10 is controlled.

[0036] When protection circuit 72 detects an overcurrent or an excessive temperature rise, it forcibly stops the output of the drive control signal from control unit 56. This stops the operation of the switching elements of inverter 40 and the rotation of brushless motor 10, thereby protecting brushless motor 10 and motor drive device 20.

[0037] A positive input terminal of the comparator 66 is connected to one end of the stator coil 12U. A negative input terminal of the comparator 66 is connected to the neutral point of the stator coils 12U, 102V, and 102W.

[0038] When driving power is supplied to brushless motor 10, a composite voltage of the driving voltage applied to stator coil 12U and the induced voltage generated in stator coil 12U is input to the positive input terminal of comparator 66 as a phase voltage.

[0039] If drive timing generation unit 54 does not output a drive timing signal to control unit 56 while brushless motor 10 is rotating and power supply from inverter 40 to stator coils 12U, 12V, and 12W is cut off, brushless motor 10 will run idle. During the idling of brushless motor 10, no drive voltage is applied to stator coil 12U, so that the induced voltage of stator coil 12U, which does not include a drive voltage, is input to the positive input terminal of comparator 66 as a phase voltage.

[0040] 2, while brushless motor 10 is idling, the output voltage of comparator 66 becomes pulsed with periods when induced voltage is generated in stator coil 12U and periods when it is not generated. As a result, while brushless motor 10 is idling, a binary output signal is output from comparator 66 to drive timing generation unit 54 in accordance with the induced voltage in stator coil 12U.

[0041] 3, while brushless motor 10 is idling, drive timing generator 54 detects the phase difference between the output voltage, which is the detection signal of U-phase Hall sensor 22, and the output voltage from comparator 66, which corresponds to the induced voltage of stator coil 12U. The output voltage from comparator 66, which corresponds to the induced voltage of stator coil 12U, is generated in response to the position of rotor 14, and therefore represents the accurate rotational position of brushless motor 10.

[0042] In this embodiment, the ideal phase difference is such that the rising edge indicating the generation timing of the detection signal of the Hall sensor 22 of the U phase is 30° ahead of the rising edge indicating the generation timing of the induced voltage of the stator coil 12U output by the comparator 66. Hereinafter, the induced voltage of the stator coil 12U output by the comparator 66 is also simply referred to as the induced voltage of the stator coil 12U.

[0043] This deviation from the ideal phase difference occurs due to an angular deviation in the installation position of the Hall sensor 22 from the ideal position, a deviation in the characteristics of the Hall sensor 22, the occurrence of noise, or the like.

[0044] When there is a deviation from the ideal phase difference, the drive timing generating section 54 performs a correction so that a correction value corresponding to the deviation is reflected in the drive timing for outputting the drive control signal. [2. Processing] Next, the process executed by the motor control device 50 when starting up the brushless motor 10 will be described with reference to FIG.

[0045] In S400, when a command signal to start brushless motor 10 is output from air conditioner ECU 4, motor control device 50 starts supplying electricity to brushless motor 10 and gradually increases the rotation speed. In parallel with this, drive timing generation unit 54 detects the rotation speed of brushless motor 10 based on the count value of a period counter (not shown) provided in drive timing generation unit 54 itself.

[0046] In S402, the drive timing generation unit 54 determines whether the rotation speed of the brushless motor 10 has reached a predetermined rotation speed or higher, for example, 450 rpm or higher. If the determination in S402 is Yes, that is, if the rotation speed of the brushless motor 10 has reached 450 rpm or higher, in S404, the drive timing generation unit 54 stops outputting the drive timing signal to the control unit 56, thereby turning off the power supply to the inverter 40.

[0047] As a result, the power supply to stator coils 12U, 12V, and 12W is cut off, causing brushless motor 10 to rotate idly, and the output voltage of U-phase stator coil 12U input to the positive terminal of comparator 66 becomes only the induced voltage.

[0048] The induced voltages generated in the stator coils 12U, 12V, and 12W reflect the actual rotational position of the rotor 14. In this embodiment, of the induced voltages generated in the stator coils 12U, 12V, and 12W, the induced voltage in the stator coil 12U is used.

[0049] In S406, the drive timing generation unit 54 determines whether or not the signal period of the detection signal output by the Hall sensor 22 is equal to or shorter than a predetermined period. In the present embodiment, this determination is performed on the count value of a period timer counter that counts the signal period of the detection signal output by the Hall sensor 22 of the U phase.

[0050] If the signal period of the detection signal becomes longer than the predetermined period, the period timer counter may overflow. If the period timer counter overflows, the process following S410 when the signal period of the detection signal is equal to or shorter than the predetermined period cannot be executed properly. Therefore, by setting the predetermined period, the process is differentiated depending on whether the signal period of the detection signal is equal to or shorter than the predetermined period.

[0051] If the determination in S406 is Yes, that is, if the signal period of the detection signal output by the Hall sensor 22 is equal to or shorter than the predetermined period, it is determined that the rotation of the brushless motor 10 is normal, and the drive timing generation unit 54 shifts the process to S410.

[0052] If the determination in S406 is No, that is, if the signal period of the detection signal indicated by the Hall sensor 22 is longer than the predetermined period, the drive timing generating unit 54 determines that the rotation of the brushless motor 10 is abnormally slow, and proceeds to S408.

[0053] In S408, the drive timing generation unit 54 calculates the current angle delay amount using the angle delay amount that is the learned value learned in the past, and proceeds to S430. The angle delay amount learned in the past is the angle delay amount learned in S422 and S426 described later.

[0054] In S410, the drive timing generation unit 54 detects five signal periods of the detection signal output by the Hall sensor 22. The periodic time of each of the five periods is stored in a register, memory, or the like from the period timer counter described above.

[0055] In addition, in S410, the drive timing generating unit 54 detects the phase difference time from the rising edge of the detection signal of the Hall sensor 22 of the U phase to the rising edge of the induced voltage of the stator coil 12U for the next period after each period for which the period time has been detected. The phase difference time is stored in a register, memory, or the like from the above-mentioned phase difference timer counter.

[0056] The phase difference time counted by the phase difference timer counter is the delay time (n) shown in Figures 5, 6, and 8. n=0, 1, 2, 3, 4, and 0≦delay time (n)<electrical angle 360° time.

[0057] The drive timing generating unit 54 discards the first delay time (0) among the five detected delay times (n). This is because, since a return current occurs immediately after the power supply to the brushless motor 10 is turned off, the first time when the rotor 14 rotates idly immediately after the power supply is stopped, there is a possibility that an appropriate induced voltage cannot be obtained from the stator coil 12U.

[0058] Here, when there are multiple rising edges of the induced voltage of the stator coil 12U during a period of 360 electrical degrees as shown in the periods (1) and (3) of electrical angle 360° in Fig. 8, it is considered that the forward and reverse orders described below are mixed. In this case, the phase difference timer counter detects the delay time up to the first rising edge of the induced voltage of the stator coil 12U, but does not detect the delay times for the second and subsequent rising edges.

[0059] Also, as shown in FIG. 8, if there is no rising edge of the induced voltage of the stator coil 12U in the period following the periods of electrical angle 360° times (1) and (4), the delay times (1) and (4) are set to electrical angle 360° times (1) and (4), respectively.

[0060] In S412, the drive timing generation unit 54 determines whether the rising edge of the Hall sensor 22 of the U phase and the rising edge of the induced voltage of the stator coil 12U are in the normal order based on the following equation (1), with n=1 as the initial value. The electrical angle 360° time (n) that is the subject of determination of the delay time (n) is the electrical angle 360° time (n) of the period immediately preceding the delay time (n).

[0061] Delay time (n) ≤ electrical angle 360° time (n) / 2 (1) Equation (1) indicates that an induced voltage in the stator coil 12U is generated within a period equal to or shorter than ½ of the signal period of the detection signal after the detection signal of the Hall sensor 22 of the U phase is generated.

[0062] When the delay time (n) satisfies equation (1), the order is forward, and when the delay time (n) does not satisfy equation (1), the order is reverse. In other words, the forward order indicates that the rising edge of the Hall sensor 22 of the U phase occurs earlier than the rising edge of the induced voltage of the stator coil 12U.

[0063] The reverse order also indicates that the rising edge of the Hall sensor 22 for the U phase occurs at a later timing than the rising edge of the induced voltage of the stator coil 12U. As shown in FIG. 5, when the delay time (n) of the rising edge of the induced voltage satisfies the formula (1), the rising edge of the Hall sensor 22 of the U phase and the rising edge of the induced voltage of the stator coil 12U are in normal order.

[0064] In contrast, as shown in FIG. 6, when the delay time (n) of the rising edge of the induced voltage does not satisfy formula (1), the rising edge of the U-phase Hall sensor 22 and the rising edge of the induced voltage of the stator coil 12U are in reverse order.

[0065] The case where formula (1) is not satisfied means that the induced voltage in the stator coil 12U occurs with a delay of more than ½ the signal period of the detection signal after the detection signal of the Hall sensor 22 of the U phase is generated.

[0066] As shown in Fig. 6, the rising edge of the Hall sensor 22 of the U phase and the rising edge of the induced voltage of the stator coil 12U successively occur in reverse order when, for example, the magnetic flux density detected by the Hall sensor 22 is small as shown in Fig. 7. When the magnetic flux density is small, the timing at which the Hall sensor 22 outputs the detection signal becomes delayed, causing the reverse order.

[0067] For example, when the temperature of the magnets of rotor 14 increases due to heating from heat generating elements of the vehicle adjacent rotor 14, such as stator 12, the magnetic flux density of the magnets of rotor 14 decreases and becomes smaller.

[0068] 8, the order of the rising edge of the Hall sensor 22 of the U phase and the rising edge of the induced voltage of the stator coil 12U may be mixed in both forward and reverse order. This is considered to be due to the generation of noise or the like.

[0069] If the determination in S412 is Yes, that is, if the rising edge of the Hall sensor 22 of the U phase and the rising edge of the induced voltage of the stator coil 12U are in normal order, the drive timing generation unit 54 increments n by +1 in S414 and proceeds to S418.

[0070] If the determination in S412 is No, that is, if the rising edge of the Hall sensor 22 of the U phase and the rising edge of the induced voltage of the stator coil 12U are in reverse order, in S416 the drive timing generation unit 54 increments n and the number of times reverse order has occurred by +1, and proceeds to S418.

[0071] As described above, if there are a plurality of rising edges of the induced voltage of stator coil 12U within a period of 360 electrical degrees, the delay times from the second onwards are not detected. Also, as described above, if there is no rising edge of the induced voltage of the stator coil 12U during the time of 360 electrical degrees, the delay time is set to the time of 360 electrical degrees before that period. In this case, since formula (1) is not normally satisfied, it is determined that the order is reversed. In the example of FIG. 8, the delay times (1) and (4) are determined to be reversed.

[0072] In S418, the drive timing generation unit 54 determines whether n=5, that is, whether the determination in S412 has been performed for delay times (1) to (4). The drive timing generation unit 54 repeats the processes of S412 to S416 four times until n=5.

[0073] If the determination in S418 is Yes, that is, if the processes in S412 to S416 are repeated four times, then in S420, the drive timing generation section 54 determines whether the number of occurrences of the reverse order is 0 or not.

[0074] If the determination in S420 is No, that is, if the reverse order has occurred at least once, the process proceeds to S424. If the determination in S420 is Yes, that is, the number of occurrences of reverse order is 0 and all are normal order, in S422, the drive timing generation unit 54 converts the average of the delay times (n) into angles based on the following equation (2) to calculate the angle delay amount in the normal order. After executing S422, the drive timing generation unit 54 transitions the process to S430.

[0075]

number

[0076] In S424, the drive timing generation unit 54 determines whether the number of occurrences of reverse order is 4, that is, whether all the occurrences were reverse order. If the determination in S424 is No, that is, if the number of occurrences of reverse order is between 1 and 3, with both normal and reverse orders being mixed, the process proceeds to S428.

[0077] If the determination in S424 is Yes, that is, if all four times are in the reverse order, in S426, the drive timing generation unit 54 converts the average of (delay time (n) - electrical angle 360° time (n)) into an angle based on the following equation (3) to calculate the angle delay amount in the reverse order. After executing S426, the drive timing generation unit 54 transitions the process to S430.

[0078]

number

[0079] In S428, the drive timing generation unit 54 determines that since forward and reverse orders are mixed, correction cannot be made with the current phase difference, and calculates the current angle delay amount based on the angle delay amounts previously learned in S422 and S426.

[0080] For example, the drive timing generation unit 54 calculates the average of the angle delay amounts learned in the most recent predetermined number of times as the current angle delay amount. Alternatively, the drive timing generation unit 54 sets the angle delay amount learned in the main process immediately before this one as the current angle delay amount.

[0081] When the Hall sensor 22 is set at the ideal position and the characteristics of the Hall sensor 22 are normal, the angle delay amount is 30°. Therefore, in S430, the drive timing generation unit 54 calculates a correction value so as to correct the deviation angle between the calculated angle delay amount and 30°.

[0082] In S432, the drive timing generation unit 54 stores the angle delay amount calculated and learned in S4422 and S426 as a learned value. In S434, the motor control device 50 corrects the energization timing of the stator coils 12U, 12V, and 12W based on the correction value calculated in S430, and executes normal control to maintain the rotation speed based on the speed command value.

[0083] In the embodiment described above, the Hall sensor 22 corresponds to the rotation sensor, and the drive timing generation section 54 corresponds to the phase difference detection section, the period detection section, the sequence determination section, and the correction section. Moreover, S406 corresponds to the processing in the cycle detection unit, S410 and S412 correspond to the processing in the phase difference detection unit, S412 corresponds to the processing in the order determination unit, and S408 and S420 to S434 correspond to the processing in the correction unit.

[0084] [3. Effects] According to the embodiment described above, the following effects can be obtained. (3a) In this embodiment, the energization timings of the stator coils 12U, 12V, and 12W are corrected based on a learned value learned in the past for the purpose of correction, rather than a fixed correction value. In this way, by correcting the energization timings of the stator coils 12U, 12V, and 12W using a learned value learned in the past rather than using a fixed value, the energization timings of the stator coils 12U, 12V, and 12W can be corrected with high accuracy.

[0085] (3b) Power is turned off to all phases of the stator coils 12U, 12V, and 12W, and the induced voltage of the stator coil 12U is detected while the rotor 14 is idling. Since the phase voltage of the stator coil 12U does not include a drive voltage while the rotor 14 is idling, the induced voltage can be accurately detected by detecting the phase voltage.

[0086] [4. 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.

[0087] (4a) In the above-described embodiment, the timing of energization to brushless motor 10 is corrected based on the phase difference between the output voltage of Hall sensor 22U and the induced voltage of stator coil 12U among the three phases. However, the timing of energization to brushless motor 10 may be corrected based on the phase difference between the output voltage of Hall sensor 22V and the induced voltage of stator coil 12V, or the phase difference between the output voltage of Hall sensor 22W and the induced voltage of stator coil 12W.

[0088] (4b) In the above-described embodiment, the electrical angle 360° time (n) that is the object of judgment of the delay time (n) is the electrical angle 360° time (n) of the period immediately preceding the delay time (n), but this is not limited thereto. The electrical angle 360° time (n) that is the object of judgment of the delay time (n) may be the electrical angle 360° time (n) of the same period as the delay time (n).

[0089] (4c) The motor controller 50 and techniques described herein may be implemented by a special purpose computer provided by configuring a processor and memory programmed to perform one or more functions embodied in a computer program.

[0090] Alternatively, the motor controller 50 and techniques described in this disclosure may be implemented in a special purpose computer provided by configuring a processor with one or more special purpose hardware logic circuits.

[0091] Alternatively, the motor controller 50 and techniques described herein may be implemented using one or more special purpose computers configured using a processor and memory programmed to perform one or more functions in combination with a processor configured with one or more hardware logic circuits.

[0092] The computer program may be stored in a computer-readable non-transitory recording medium as instructions executed by a computer. The method for realizing the functions of each unit included in the motor control device 50 does not necessarily need to include software, and all of the functions may be realized using one or more pieces of hardware.

[0093] (4d) In the above-described embodiments, multiple functions of a single component may be realized by multiple components, and vice versa.

[0094] Furthermore, 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-mentioned embodiments may be omitted. Also, at least part of the configuration of the above-mentioned embodiments may be added to or substituted for the configuration of another of the above-mentioned embodiments.

[0095] (4e) In addition to the motor control device 50 described above, the present disclosure can be realized in various forms, such as a system including the motor control device 50 as a component, a program for causing a computer to function as the motor control device 50, a non-transient physical recording medium such as a semiconductor memory on which the program is recorded, and a motor control method. [Explanation of symbols]

[0096] 10: brushless motor, 12: stator, 12U, 12V, 12W: stator coil, 14: rotor, 22: hall sensor (rotation sensor), 50: motor control device, 54: drive timing generation unit (phase difference detection unit, period detection unit, sequence determination unit, correction unit)

Claims

1. A motor control device (50) for controlling the rotation of a brushless motor (10), a phase difference detection unit (54, S410, S412) configured to detect a phase difference between a generation timing of a detection signal of a rotation sensor (22) that detects a rotational position of a rotor (14) having magnetic poles and a generation timing of an induced voltage generated in a stator coil (12U, 12V, 12W) of a stator (12); a period detection unit (54, S406) configured to detect a signal period of the detection signal; an order determination unit (54, S412) configured to determine an order of the generation timing of the detection signal and the generation timing of the induced voltage; a correction unit (54, S408, S420 to S434) configured to correct a timing of energization to the stator coil based on the phase difference detected by the phase difference detection unit when the signal period of the detection signal detected by the period detection unit is equal to or shorter than a predetermined period and the order determination unit determines that the detection signal is in a forward order in which the generation timing of the detection signal is ahead of the generation timing of the induced voltage, or the order determination unit determines that the detection signal is in a reverse order in which the generation timing of the detection signal is behind the generation timing of the induced voltage, and to correct the timing of energization to the stator coil based on a learned value previously learned for correcting the timing of energization in the forward order or the reverse order, when the signal period is equal to or shorter than the predetermined period and the forward order and the reverse order are mixed, or when the signal period is longer than the predetermined period; A motor control device comprising:

2. 2. The motor control device according to claim 1, the phase difference detection unit is configured to detect the phase difference when power supply to the stator coil is turned off during rotation of the rotor. Motor control device.

3. 2. The motor control device according to claim 1, the order determination unit is configured to determine the order as the normal order when the induced voltage occurs within a period of ½ or less of the signal period of the detection signal after the generation of the detection signal, and to determine the order as the reverse order when the induced voltage occurs later than ½ of the signal period of the detection signal after the generation of the detection signal. Motor control device.

Images