JP2010119220A - Motor drive control device - Google Patents

Abstract

A motor drive control device capable of driving a motor without being affected by a detection error of a rotor position is provided.
A motor drive control device includes Hall sensors (2u, 2v, 2w), a detection error calculation unit (4), a correction unit (6), and a drive voltage generation unit (7). Hall sensors 2u, 2v, 2w detect magnetic poles of rotor 53 and output position detection signals Hu, Hv, Hw. The detection error calculation unit 4 detects the position detection error of the rotor 53 in the hall sensors 2u, 2v, 2w based on the position detection signals Hu, Hv, Hw when the rotation speed of the motor 51 is less than the first predetermined rotation speed. Is calculated. The correction unit 6 corrects the position detection signals Hu, Hv, and Hw when the rotation number of the motor 51 is equal to or higher than the first predetermined rotation number with a detection error. The drive voltage generator 7 generates drive voltages SU, SV, SW based on the corrected position detection signals Hu ′, Hv ′, Hw ′, and outputs them to the motor 51.
[Selection] Figure 1

Description

  The present invention relates to a motor drive control device, and more particularly to a motor drive control device that controls drive of a motor including a stator having a drive coil and a rotor having a plurality of magnetic poles.

In an air conditioner equipped with devices such as a compressor and a blower fan, a brushless motor is used as a power source for these devices. Generally, a brushless motor has a rotor made of a permanent magnet having a plurality of magnetic poles and a stator having a plurality of drive coils. For example, as disclosed in Patent Document 1, a drive voltage corresponding to the position of the rotor with respect to the stator is applied to a drive coil of the brushless motor by a motor drive control device for driving and controlling the motor. As a result, a magnetic field is generated in the drive coil by applying a current corresponding to the applied drive voltage, and the rotor rotates. When detecting the position of the rotor with respect to the stator, a plurality of position detection sensors such as a Hall element and a Hall IC are used. The position detection sensor grasps the position of the rotor by detecting the magnet of the rotor, and outputs a position detection signal based on the position of the rotor.
JP 2003-264990 A

  However, the mounting position of the position detection sensor described above may vary, or the rotor may have a variation in magnetic force due to being not magnetized in a desired state. In this case, the position detection signal output from the position detection sensor is a signal in which an error with respect to the actual rotor position (hereinafter referred to as rotor detection error) has occurred, and the motor drive control device accurately determines the position of the rotor. It will be difficult to grasp. Then, since the drive voltage output to the motor is generated based on the position detection signal in a state where the detection error of the rotor position has occurred, the motor is affected by the detection error of the rotor position and vibrates during rotation. There is a risk of noise.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a motor drive control device that can drive a motor without being affected by the detection error of the rotor position.

  A motor drive control device according to a first aspect of the present invention is a device that controls driving of a motor including a stator having a drive coil and a rotor having a plurality of magnetic poles. The motor drive control device includes a position detection unit, a detection error calculation unit, a correction unit, and a drive voltage generation unit. The position detection unit detects a magnetic pole included in the rotor and outputs a position detection signal. The position detection signal is a signal indicating the position of the rotor with respect to the stator. The detection error calculation unit calculates a detection error of the rotor position in the position detection unit based on the position detection signal when the rotation number of the motor is less than the first predetermined rotation number. The correction unit corrects the position detection signal when the rotation speed of the motor is equal to or higher than the first predetermined rotation speed with a detection error. The drive voltage generation unit generates a drive voltage for driving the motor based on the position detection signal corrected by the correction unit, and outputs the drive voltage to the motor.

  According to this motor drive control device, when the rotational speed of the motor is less than the first predetermined rotational speed, that is, when the motor is rotating at a low speed, the detection error of the rotor position in the position detector is calculated. When the rotational speed of the motor is equal to or higher than the first predetermined rotational speed, that is, when the motor is rotating at a high speed, the position detection signal is corrected by the calculated rotor position detection error. And the drive voltage produced | generated based on the position detection signal after correction | amendment is output to a motor. That is, this motor drive control device corrects the rotor position detected during high-speed rotation based on the rotor position detection error calculated during low-speed rotation of the motor, and drives the motor based on the corrected accurate rotor position. As a result, the motor is driven without being affected by the detection error of the rotor position caused by variations in the attachment position of the position detection unit. Therefore, it is possible to prevent the occurrence of vibration and abnormal noise during motor rotation caused by the influence of the detection error of the rotor position.

  A motor drive control device according to a second aspect of the present invention is the motor drive control device according to the first aspect of the present invention, wherein the detection error calculation unit calculates a detection error during a trial run of the motor.

  Examples of the test run of the motor include a production test performed before shipment of the motor and the motor drive control device. Thereby, when the motor and the motor drive control device are shipped and actually rotate at high speed, the position detection signal is corrected using the already calculated detection error, and the motor is driven. Therefore, the motor can be driven without being affected by the detection error of the rotor from the time when the motor rotates at high speed for the first time after shipment.

  A motor drive control device according to a third aspect of the present invention is the motor drive control device according to the first or second aspect of the present invention, further comprising a first storage unit. The first storage unit detects the magnetic pole next after the position detection unit detects the magnetic pole of the rotor in the case where the rotational speed of the motor is the second predetermined rotational speed satisfying a condition that is less than the first predetermined rotational speed. The first detection interval until is stored. When the detection error is calculated by the detection error calculation unit, the drive voltage generation unit generates a drive voltage for rotating the motor at the second predetermined rotation speed and outputs the drive voltage to the motor. The detection error calculation unit measures a second detection interval from when the position detection unit detects the magnetic pole of the rotor until the next detection of the magnetic pole, when the rotation number of the motor becomes approximately the second predetermined rotation number. The detection error calculation unit sets a difference between the first detection interval stored in the first storage unit and the measured second detection interval as a detection error.

  The detection error calculation unit in this motor drive control device includes a first detection interval that is predicted to be required to detect the magnetic pole next after the position detection unit detects the magnetic pole of the rotor, and an actual first measurement result. The difference between the two detection intervals is obtained, and this is determined as a detection error. Thereby, the detection error of the actual rotor position can be accurately obtained. Further, when the motor rotates at high speed, the position detection signal is corrected using the rotor position detection error thus obtained, so that a drive voltage corresponding to the actual detection error is output to the motor. .

  A motor drive control device according to a fourth aspect of the present invention is the motor drive control device according to the first or second aspect, wherein the drive voltage generation unit rotates the motor by a first predetermined rotation when the detection error is calculated by the detection error calculation unit. A drive voltage for rotating at a third predetermined number of rotations that satisfies a condition that is less than the number is generated and output to the motor. When the rotational speed of the motor reaches approximately the third predetermined rotational speed, the detection error calculation unit sets the third detection interval from when the position detection unit detects the magnetic pole of the rotor to the next detection of the magnetic pole to the mechanical angle. Then, one rotation of the motor is measured and an average value of the third detection intervals is obtained based on the measurement result. Then, the detection error calculation unit sets a difference between the obtained average value of the third detection intervals and any one of the third detection intervals as a detection error.

  The detection error calculation unit of the motor drive control device measures a third predetermined interval from the time when the position detection unit detects the magnetic pole of the rotor to the next detection of the magnetic pole, by one rotation of the motor at a mechanical angle. Then, the detection error calculation unit calculates an average value of the third predetermined interval from the measurement result, and determines a difference between the calculated average value of the third predetermined interval and an arbitrary third predetermined interval as a detection error. Thereby, the detection error of the actual rotor position can be accurately obtained. Further, when the motor rotates at high speed, the position detection signal is corrected using the rotor position detection error thus obtained, so that a drive voltage corresponding to the actual detection error is output to the motor. .

  A motor drive control device according to a fifth aspect of the present invention is the motor drive control device according to any of the first to fourth aspects of the present invention, further comprising a second storage unit. The second storage unit can store the detection error calculated by the detection error calculation unit. Then, the correction unit corrects the position detection signal when the rotational speed of the motor is equal to or higher than the first predetermined rotational speed, using the detection error stored in the second storage unit.

  According to this motor drive control device, since the calculated detection error is stored in the second storage unit, the stored detection error can be stored during high-speed rotation of the motor without calculating the detection error every time the motor is started. Can be used to correct the position detection signal.

  A motor drive control device according to a sixth aspect of the present invention is the motor drive control device according to any of the first to fifth aspects, wherein the motor to which the drive voltage based on the corrected position detection signal is output has a sinusoidal shape. Current is energized.

  Generally, the detection time from when the position detection sensor detects an arbitrary magnetic pole of the rotor until the next magnetic pole is detected is shorter when the motor rotates at a higher speed than when the motor rotates at a low speed. On the other hand, since the detection error of the rotor position is constant regardless of the rotation speed, the ratio of the detection error of the rotor position to the detection time of the position detection sensor becomes large when the motor rotates at high speed. For this reason, if the drive voltage generated when there is a variation in the position of the position detection unit during high-speed rotation of the motor is output to the motor, the desired sinusoidal current is not applied to the motor. As a result, abnormal noise and vibration are generated. However, according to the motor drive control device of the present invention, when the motor rotates at high speed, the position detection signal is corrected by the obtained rotor position detection error, and the drive voltage generated by the corrected position detection signal is applied to the motor. Since it is output, a desired sinusoidal current is applied to the motor. Therefore, no abnormal noise or vibration is generated in the motor rotating at high speed.

  According to the motor drive control device according to the first aspect of the present invention, it is possible to prevent the occurrence of vibration and abnormal noise during motor rotation caused by the influence of the rotor position detection error.

  According to the motor drive control device pertaining to the second aspect of the present invention, the motor can be driven without being affected by detection errors since the motor rotates at high speed for the first time after shipment.

  With the motor drive control device according to the third and fourth aspects of the invention, the actual rotor position detection error can be accurately obtained. Furthermore, when the motor rotates at high speed, the position detection signal is corrected using the obtained rotor position detection error, so that a drive voltage corresponding to the actual detection error is output to the motor.

  According to the motor drive control device of the fifth aspect of the present invention, the position detection signal can be corrected using the stored detection error when the motor rotates at high speed without calculating the detection error every time the motor is started. .

  According to the motor drive control device pertaining to the sixth aspect of the present invention, it is possible to prevent abnormal noise and vibration from occurring in the motor rotating at high speed.

  Hereinafter, the motor drive control device according to the present embodiment will be described in detail with reference to the drawings.

<First Embodiment>
(1) Overall and Motor Configuration FIG. 1 is an overall configuration diagram of a motor drive control system 100 including a motor 51 and a motor drive control device 1 for controlling the drive of the motor 51. Here, as a type of the motor, generally, a direct current motor, an alternating current motor, a stepping motor, a brushless motor, and the like can be cited. In the present embodiment, the case where the motor 51 is a three-phase brushless motor is taken as an example. .

  The motor 51 which concerns on this embodiment is a fan motor used for the outdoor fan 61 in the outdoor unit of an air conditioning apparatus. The motor 51 includes a stator 52 and a rotor 53.

  The stator 52 includes U-phase, V-phase, and W-phase drive coils Lu, Lv, and Lw that are star-connected. One end of each of the U-phase, V-phase, and W-phase drive coils Lu, Lv, and Lw is connected to U-phase, V-phase, and W-phase drive coil terminals TU, TV, and TW, respectively. The other ends of Lv and Lw are all connected to the terminal TN. These three-phase drive coils Lu, Lv, and Lw generate an induced voltage according to the rotational speed and the position of the rotor 53 as the rotor 53 rotates.

  The rotor 53 has a permanent magnet composed of a plurality of magnetic poles, and rotates around the rotation axis with respect to the stator 52 in a fixed state. Here, the rotor 53 according to the present embodiment includes four N-pole permanent magnets and four S-pole permanent magnets, and a configuration in which N-pole permanent magnets and S-pole permanent magnets are alternately combined. It has become. The rotation of the rotor 53 is transmitted to the outdoor fan 61 via an output shaft (not shown) that is on the same axis as the rotation shaft.

(2) Configuration of Motor Drive Control Device Next, the configuration of the motor drive control device 1 according to the present embodiment will be described. The motor drive control device 1 according to the present embodiment includes three hall sensors (corresponding to position detection units) 2u, 2v, 2w, a rotation speed detection unit 3, a detection error calculation unit 4, a storage unit 5, a correction unit 6, and a drive. A voltage generation unit 7 and a power supply unit 11 are provided.

[Hall sensor]
The three hall sensors 2u, 2v, 2w are attached in the vicinity of the drive coils Lu, Lv, Lw so as to correspond to the three-phase drive coils Lu, Lv, Lw, respectively. The hall sensors 2u, 2v, and 2w detect the position of the rotor 53 relative to the stator 52 by detecting the magnetic pole of the permanent magnet that the rotor 53 has. The hall sensors 2u, 2v, 2w send position detection signals Hu, Hv, Hw indicating the position of the rotor 53 after detection to a rotation speed detection unit 3, a detection error calculation unit 4, a correction unit 6, and a drive voltage generation unit. 7 to a PWM controller 8 (described later).

(Rotation speed detector)
The rotation speed detection unit 3 includes a detection circuit made up of a plurality of electrical components. The rotation speed detector 3 detects the rotation speed of the rotor 53 using the position detection signals Hu, Hv, Hw output from the hall sensors 2u, 2v, 2w. The detected rotation speed of the rotor 53 is taken into the detection error calculation unit 4, the correction unit 6, and the PWM control unit 8 of the drive voltage generation unit 7.

[Detection error calculation unit]
The detection error calculation unit 4 includes a microcomputer including a CPU and a memory. The detection error calculation unit 4 calculates the detection error of the position of the rotor 53 in the hall sensors 2u, 2v, 2w. In particular, the detection error calculation unit 4 according to the present embodiment calculates the detection error of the position of the rotor 53 based on the position detection signals Hu, Hv, Hw when the rotation speed of the motor 51 is less than the first predetermined rotation speed. calculate. Here, as the first predetermined rotation speed, for example, 200 rpm may be mentioned, assuming that the motor 51 normally rotates at a rotation speed of 1800 rpm, for example. That is, the detection error calculation unit 4 calculates a detection error of the position of the rotor 53 when the motor 51 rotates at a low speed such as 180 rpm lower than 200 rpm that is the first predetermined rotation speed. In the following, the rotational speed satisfying the condition less than the first predetermined rotational speed, that is, the rotational speed lower than the first predetermined rotational speed (that is, the rotational speed lower than 200 rpm, specifically 180 rpm or the like) is set to the second predetermined rotational speed. The number of revolutions.

  Here, how the position detection error of the rotor 53 is specifically calculated will be described. When the detection error calculation operation is started, first, the motor 51 rotates at a low speed, that is, at a second predetermined rotation speed (for example, 180 rpm) lower than the first predetermined rotation speed (for example, 200 rpm). At this time, the detection error calculation unit 4 measures the second detection interval from when the hall sensors 2u, 2v, 2w detect a magnetic pole on the rotor 53 until the next magnetic pole is detected. Then, the detection error calculation unit 4 detects the magnetic pole next to the Hall sensor 2u, 2v, 2w when the rotational speed of the motor 51 is the second predetermined rotational speed, and then detects the magnetic pole. The difference between the first detection interval estimated to be required for this and the actually measured second detection interval is obtained, and this is determined as the detection error of the position of the rotor 53. That is, the detection error calculation unit 4 sets a difference between the first detection interval that is an estimated value and the second detection interval that is an actual value as a detection error. The first detection interval described above is a value determined in advance by desktop calculation, simulation, experiment, or the like, and can be said to be a theoretical value.

  FIG. 2 shows the detection error of the position of the rotor 53 obtained in this way. As shown in FIG. 2, the detection error of the position of the rotor 53 is that the position of the rotor 53 is not detected at the timing when the position of the rotor 53 should be detected. Therefore, it corresponds to the amount deviated from the timing that should be detected. For example, in FIG. 2, when the mechanical angle of the motor 51 is in the vicinity of 120 °, the detection of the position of the rotor 53 should be performed when it is originally 120 °. The detection error at position 53 is a negative value. Further, when the mechanical angle of the motor 51 is around 180 °, the position of the rotor 53 should be detected when it is originally 180 °, but it is performed earlier than 180 °. The detection error is a positive value. If there is such a detection error, the current supplied to the motor 51 does not have an ideal perfect sine wave waveform, but a distorted waveform due to the influence of the detection error. FIG. 2 shows a case where the three hall sensors 2u, 2v, 2w are provided 120 degrees apart from each other, and the drive coil Lu is energized among the three-phase drive coils Lu, Lv, Lw. Only the current is shown as an example. A dotted waveform IU ′ in FIG. 2 represents a waveform of a current that will be supplied to the drive coil Lu of the motor 51 when there is no detection error of the position of the rotor 53. A solid waveform IU is The waveform of the electric current supplied to the drive coil Lu of the motor 51 when there is a detection error of the position of the rotor 53 is shown.

[Storage section]
The storage unit 5 includes a nonvolatile memory such as a flash memory or an EEPROM, and includes a first storage area 5a (corresponding to the first storage part) and a second storage area 5b (corresponding to the second storage part). The first storage area 5 a stores a first detection interval used when the detection error calculation unit 4 calculates a detection error of the position of the rotor 53. The first detection interval is stored in advance in the first storage area 5a before the motor 51 and the motor drive control device 1 are shipped. On the other hand, the detection error itself of the position of the rotor 53 calculated by the detection error calculation unit 4 is stored in the second storage area 5b.

[Correction section]
Similar to the detection error calculation unit 4, the correction unit 6 is configured by a microcomputer including a CPU and a memory. The correction unit 6 uses the position detection signals Hu, Hv, Hw output from the hall sensors 2u, 2v, 2w using the position detection error of the rotor 53 stored in the second storage area 5b of the storage unit 5. Correct each one. More specifically, the correction unit 6 according to the present embodiment calculates the position detection signals Hu, Hv, Hw when the rotation number of the motor 51 is equal to or higher than the first predetermined rotation number by the detection error calculation unit 4. Correct with the detection error. That is, if the first predetermined rotation speed is 200 rpm, the correction unit 6 outputs from each Hall sensor 2u, 2v, 2w when the motor 51 is rotating at a high speed like 1800 rpm which is 200 rpm or more. The position detection signals Hu, Hv, Hw are corrected. For example, if the detection error of the position of the rotor 53 is a negative value, the correction unit 6 subtracts the detection error from the position detection signals Hu, Hv, Hw when the motor 51 rotates at high speed. Conversely, if the detection error of the position of the rotor 53 is a positive value, the correction unit 6 adds the detection error to the position detection signals Hu, Hv, Hw when the motor 51 rotates at high speed.

  In the following, in order to distinguish between the position detection signal before correction and the position detection signal after correction, the position detection signal before correction is expressed as “Hu, Hv, Hw” and corrected. The subsequent position detection signal is represented as “Hu ′, Hv ′, Hw ′”. By the correction operation described above, the correction unit 6 can obtain position detection signals Hu ′, Hv ′, and Hw ′ that indicate the actual position of the rotor 53 without including the detection error of the position of the rotor 53.

[Drive voltage generator]
The drive voltage generator 7 generates drive voltages SU, SV, and SW for driving the motor 51 based on the position detection signals Hu, Hv, and Hw, and outputs them to the motor 51. In particular, the driving voltage generation unit 7 according to the present embodiment, if the correction operation of the position detection signals Hu, Hv, Hw is performed by the correction unit 6, the corrected position detection signals Hu ′, Hv ′, Based on Hw ′, drive voltages SU, SV, SW are generated and output to the motor 51. Further, when the detection error is calculated by the detection error calculation unit 4, the drive voltage generation unit 7 generates the drive voltages SU, SV, SW for rotating the motor 51 at the second predetermined rotation number, This is output to the motor 51. Such a drive voltage generation unit 7 includes a PWM control unit 8, a gate control voltage generation unit 9, and an output circuit 10.

  The PWM control unit 8 determines the duty of the drive voltages SU, SV, SW applied to the drive coils Lu, Lv, Lw based on the rotation speed of the motor 51 and the position detection signals Hu, Hv, Hw. Then, the PWM control unit 8 outputs a PWM duty voltage V-duty indicating the determined duty to the gate control voltage generation unit 9. In particular, when the drive voltage generation unit 7 acquires the corrected position detection signals Hu ′, Hv ′, and Hw ′ from the correction unit 6, the drive voltage generation unit 7 does not correct the corrected position detection signals Hu, Hv, and Hw. Using the position detection signals Hu ′, Hv ′, Hw ′, the duty of the drive voltages SU, SV, SW is determined. In addition, when the detection error calculation unit 4 calculates the detection error, the PWM control unit 8 determines the duty of the drive voltages SU, SV, SW so that the motor 51 rotates at the second predetermined rotation speed. To do.

  The gate control voltage generation unit 9 controls the output circuit 10 so that the drive voltages SU, SV, SW having the duty determined by the PWM control unit 8 are output from the output circuit 10 to the motor 51. More specifically, the gate control voltage generation unit 9 is a gate for controlling on and off of the insulated gate bipolar transistors Q1 to Q6 based on the PWM duty voltage V-duty output from the PWM control unit 8. Control voltages Gu, Gx, Gv, Gy, Gw, and Gz are generated. The generated gate control voltages Gu, Gx, Gv, Gy, Gw, and Gz are applied to the gate terminals of the insulated gate bipolar transistors Q1 to Q6.

  The output circuit 10 is a circuit for outputting drive voltages SU, SV, SW based on the gate control voltages Gu, Gx, Gv, Gy, Gw, Gz to the motor 51, and is an insulated gate bipolar transistor Q1 to Q6 ( Hereinafter, it is simply referred to as a transistor) and reflux diodes D1 to D6. The transistors Q1 and Q2, Q3 and Q4, Q5 and Q6 are connected in series between the power supply wiring and the GND line. The connection points NU, NV, NW between the transistors Q1 and Q2, Q3 and Q4, Q5 and Q6 are connected to the U-phase, V-phase and W-phase drive coil terminals TU, TV and TW of the motor 51, respectively. ing. The diodes D1 to D6 have such characteristics that they are turned on when a reverse voltage is applied to the transistors Q1 to Q6, and are connected in parallel to the transistors Q1 to Q6.

  According to the output circuit 10 having such a configuration, the transistors Q1 to Q6 are turned on and off based on the gate control voltages Gu, Gx, Gv, Gy, Gw, and Gz applied to the respective gate terminals, so that the PWM control is performed. The drive voltages SU, SV, SW having the duty determined by the unit 8 are applied to the drive coils Lu, Lv, Lw.

〔Power supply part〕
The power supply unit 11 generates a DC voltage Vcc by converting an external commercial power supply (not shown), which is an AC voltage, into a direct current, and supplies this to the output circuit 10 via a power supply wiring. The power supply unit 11 includes a function unit that appropriately changes the voltage value of the DC voltage Vcc according to the duty of the drive voltages SU, SV, SW, the rotation speed of the motor 51, and the like. Examples of such a functional unit include a voltage adjustment circuit and a booster circuit.

(3) Operation of Motor Drive Control Device (3-1) Flow of a Series of Operations FIG. 3 is a flowchart for explaining a flow of a sequence of operations performed by the motor drive control device 1.

  Steps S1 to S3: When the overall control unit (not shown) of the air conditioner instructs to start the motor 51 (Yes in S1), the correction unit 6 is stored in the second storage area 5b of the storage unit 5. It is determined whether or not the detection error of the position of the rotor 53 has already been stored (S2). When the detection error of the position of the rotor 53 is not stored in the second storage area 5b (No in S2), the motor drive control device 1 performs a detection error calculation operation (S3). The flow of the detection error calculation operation will be described later.

  Step S4: When the detection error of the position of the rotor 53 is already stored in the second storage area 5b in Step S2 (Yes in S2), the drive voltage generator 7 starts the motor 51. At this time, the drive voltage generator 7 generates the drive voltages SU, SV, and SW so that the motor 51 performs steady rotation at a rotation speed of 1800 rpm which is equal to or higher than a first predetermined rotation speed (for example, 200 rpm). To 51.

  Steps S5 to S6: When the current rotational speed of the motor 51 becomes approximately 1800 rpm (Yes in S5), the correction unit 6 uses the detection error of the position of the rotor 53 in the second storage area 5b in the storage unit 5. Thus, the position detection signals Hu, Hv, Hw output from the current Hall sensors 2u, 2v, 2w (that is, the position detection signals Hu, Hv, Hw output when the motor 51 is rotating at a steady speed of approximately 1800 rpm). ) Is corrected (S6). Until the current rotation speed of the motor 51 reaches approximately 1800 rpm (No in S5), the drive voltage generation unit 7 continues to output the drive voltages SU, SV, and SW in Step S4 to the motor 51.

  Step S <b> 7: The drive voltage generator 7 generates drive voltages SU, SV, and SW based on the position detection signals Hu ′, Hv ′, and Hw ′ corrected in Step S <b> 6 and outputs them to the motor 51. The energization waveform of the motor 51 to which the drive voltages SU, SV, and SW are output has a sine wave shape without distortion as shown in FIG. 4 (currents IU ′, IV ′, IW ′ in FIG. 4).

(3-2) Flow of Detection Error Calculation Operation FIG. 5 is a flowchart for explaining the flow of the detection error calculation operation performed by the motor drive control device 1.

  Step S11: The drive voltage generator 7 sets the drive voltages SU, SV, and SW so that the motor 51 rotates at a second predetermined rotation speed (for example, 180 rpm) smaller than the first predetermined rotation speed (for example, 200 rpm). Generated and output to the motor 51.

  Steps S12 to S13: When the current rotational speed of the motor 51 becomes approximately the second predetermined rotational speed (that is, 180 rpm) (Yes in S12), the detection error calculation unit 4 determines that each of the hall sensors 2u, 2v, 2w An interval for detecting the magnetic pole, that is, a second detection interval is measured (S13). Note that the drive voltage generation unit 7 continues to output the drive voltages SU, SV, and SW in step S11 to the motor 51 until the current rotation number of the motor 51 reaches approximately the second predetermined rotation number (No in S12). .

  Steps S <b> 14 to S <b> 15: The detection error calculation unit 4 obtains a difference between the first detection interval in the first storage area 5 a in the storage unit 5 and the second detection interval measured in step S <b> 13, and calculates this difference as the position of the rotor 53. (S14). Then, the detection error calculation unit 4 writes the detection error obtained in step S14 in the second storage area 5b of the storage unit 5 (S15).

(4) Effect (A)
According to the motor drive control device 1 according to the present embodiment, when the rotation speed of the motor 51 is less than a first predetermined rotation speed (for example, 200 rpm) (specifically, 180 rpm), that is, when the motor 51 is rotating at a low speed. In addition, the detection error of the position of the rotor 53 in the hall sensors 2u, 2v, 2w is calculated. When the rotation speed of the motor 51 is equal to or higher than the first predetermined rotation speed (for example, 1800 rpm), that is, when the motor 51 is rotating at a high speed, the position detection signals Hu and Hv are detected by the calculated position detection error of the rotor 53. , Hw are corrected, and drive voltages SU, SV, SW are generated based on the corrected position detection signals Hu ′, Hv ′, Hw ′. In other words, the motor drive control device 1 corrects the position of the rotor 53 detected at the time of high speed rotation based on the detection error of the position of the rotor 53 calculated at the time of low speed rotation of the motor 51, and based on the corrected accurate position of the rotor 53. The motor 51 is driven. As a result, the motor 51 is driven without being affected by the detection error of the rotor position caused by variations in the mounting positions of the hall sensors 2u, 2v, 2w. Therefore, it is possible to prevent the occurrence of vibration and abnormal noise when the motor 51 rotates due to the influence of the detection error of the position of the rotor 53.

(B)
Further, the detection error calculation unit 4 in the motor drive control device 1 has a first detection interval predicted to be required for the Hall sensors 2u, 2v, 2w to detect the magnetic pole of the rotor 53 and then to detect the magnetic pole. The difference from the actual second detection interval, which is the measurement result, is obtained, and this is determined as a detection error. Thereby, the detection error of the actual position of the rotor 53 can be accurately obtained. Further, the position detection signals Hu, Hv, Hw when the motor 51 rotates at high speed (for example, during steady rotation) are corrected using the rotor position detection error thus obtained. For this reason, when the motor 51 rotates at high speed, drive voltages SU, SV, SW in accordance with actual detection errors are output to the motor 51.

(C)
Further, according to the motor drive control device 1, since the calculated detection error is stored in the second storage area 5 b of the storage unit 5, the high speed of the motor 51 can be calculated without calculating the detection error every time the motor 51 is started. During rotation, the position detection signals Hu, Hv, and Hw can be corrected using the stored detection error.

(D)
In general, the detection time from when the Hall sensors 2u, 2v, 2w detect an arbitrary magnetic pole of the rotor 53 until the next magnetic pole is detected is shorter when the motor 51 rotates at a higher speed than when the motor 51 rotates at a low speed. Become. On the other hand, since the detection error of the position of the rotor 53 is constant without depending on the rotation speed of the motor 51, the detection of the position of the rotor 53 in the detection time of the hall sensors 2u, 2v, 2w when the motor 51 rotates at high speed. The error rate increases. Therefore, when the drive voltages SU, SV, SW generated in a state where the mounting positions of the Hall sensors 2u, 2v, 2w are varied during the high speed rotation of the motor 51 are output to the motor 51, As indicated by the solid line in FIG. 2, a desired sinusoidal current is not applied, resulting in abnormal noise and vibration. However, according to the motor drive control device 1 according to the present embodiment, when the motor 51 rotates at high speed, the position detection signals Hu, Hv, Hw are corrected by the obtained detection error of the position of the rotor 53, and position detection after correction is performed. Drive voltages SU, SV, SW generated by the signals Hu ′, Hv ′, Hw ′ are output to the motor 51. Therefore, as shown in FIG. 4, the motor 51 is energized with a desired sinusoidal current. Therefore, no abnormal noise or vibration is generated in the motor 51 rotating at high speed.

<Other embodiments>
(A)
In the above embodiment, it has been described that the detection error calculation unit 4 simply calculates the detection error of the position of the rotor 53 when the motor 51 rotates at a low speed. However, the detection error calculation unit 4 may perform the detection error calculation operation shown in FIG. The test operation of the motor 51 includes before the motor 51 and the motor drive control device 1 are shipped, that is, at the time of a production test performed at a production factory on the production line. Thereby, when the motor 51 and the motor drive control device 1 are shipped and actually rotate at a high speed, the position detection signals Hu, Hv, Hw are corrected using the already calculated detection error, and the motor 51 is driven. The Therefore, the motor 51 can be driven without being affected by the detection error of the position of the rotor 53 from the time when the actual high speed rotation is performed for the first time.

(B)
As shown in FIG. 5, the detection error calculation unit 4 according to the above embodiment has a difference between a first detection interval, which is an estimated value determined in advance by desktop calculation or simulation, and a second detection interval actually measured. In the above description, the detection error is determined. However, the method of calculating the detection error of the position of the rotor 53 may be the following method instead of the above method using the first detection interval. FIG. 6 is a flowchart showing a flow of a method different from the detection error calculation method according to the embodiment.

  Step S21: The drive voltage generator 7 drives the drive voltages SU and SV so that the motor 51 rotates at a third predetermined rotation speed (for example, 180 rpm) that satisfies the condition that the motor 51 is less than the first predetermined rotation speed (for example, 200 rpm). , SW are generated and output to the motor 51.

  Steps S22 to S23: When the current rotational speed of the motor 51 becomes approximately the third predetermined rotational speed (that is, 180 rpm) (Yes in S22), the detection error calculation unit 4 uses the Hall sensors 2u, 2v, and 2w as magnetic poles. The third detection interval from when the first magnetic pole is detected until the next magnetic pole is detected is measured. In particular, the detection error calculation unit 4 measures the third detection interval by one rotation of the motor 51 with a mechanical angle (S23). That is, the detection error calculation unit 4 measures the third detection interval by the amount that the motor 51 rotates 360 degrees. Until the current rotational speed of the motor 51 reaches approximately the third predetermined rotational speed (No in S22), the drive voltage generation unit 7 determines that the driving voltage SU, which causes the motor 51 to rotate at the third predetermined rotational speed, The SV and SW are continuously output to the motor 51.

  Steps S24 to S25: The detection error calculation unit 4 obtains an average value of the third detection intervals based on the measurement result of step S23, that is, the third detection interval for one rotation of the motor 51 with the mechanical angle (S24). Next, the detection error calculation unit 4 obtains a difference between the average value of the third detection intervals obtained in step S24 and any one of the third detection intervals measured in step S23, and this is obtained as the position of the rotor 53. A detection error is determined (S25).

  Step S <b> 26: The detection error calculation unit 4 writes the detection error obtained in step S <b> 25 in the second storage area 5 b of the storage unit 5.

  According to such a detection error calculation method, the detection error of the actual rotor 53 position can be accurately obtained as in the above embodiment. Further, the position detection error of the rotor 53 obtained by such a calculation method is used for correcting the position detection signals Hu, Hv, Hw when the motor 51 rotates at high speed (for example, during steady rotation). The position detection signals Hu ′, Hv ′, and Hw ′ are used to generate the drive voltages SU, SV, and SW. For this reason, when the motor 51 rotates at high speed, drive voltages SU, SV, SW in accordance with actual detection errors are output to the motor 51.

(C)
In the above embodiment, it has been described that the detection error of the position of the rotor 53 calculated by the detection error calculation unit 4 is stored in the second storage area 5 b of the storage unit 5. However, the detection error of the position of the rotor 53 is not stored in the second storage area 5b of the storage unit 5 configured by flash memory or EERPOM, but is detected by the detection error calculation unit 4 configured by a microcomputer or correction. It may be stored in the memory of the unit 6.

  Further, the detection error of the position of the rotor 53 may not be stored in a storage medium such as a memory or an EEPROM, but may be calculated every time the motor 51 is started. In this case, each time the motor 51 is started, the motor 51 first rotates at a low speed, and the detection error calculation unit 4 calculates a detection error of the position of the rotor 53 in the motor 51 in the low speed rotation state. And the correction | amendment part 6 correct | amends position detection signal Hu, Hv, Hw using this detection error, after the motor 51 will be in a high speed rotation state.

(D)
In the above embodiment, one storage unit 5 stores a storage area for storing the first detection interval (that is, the first storage area 5a) and a storage area for storing the detection error of the position of the rotor 53 (that is, the second storage). The case of having the region 5b) has been described. However, the storage area is not divided in order to store each detection interval in one storage unit, but a storage unit such as an EEPROM for storing the first detection interval and the detection error of the position of the rotor 53 are stored. A storage unit such as an EEPROM may be provided separately.

(E)
In the above embodiment, the case where the motor 51 is a three-phase motor has been described as an example. However, the motor 51 is not limited to a three-phase motor, and may be a two-phase motor, for example.

  In the above embodiment, the case where the rotor 53 has a permanent magnet composed of eight magnetic poles has been described. However, the number of magnetic poles of the rotor 53 is not limited to 8 poles, and may be 2 poles or the like.

  The motor drive control device according to the present invention has an effect that it is possible to prevent the occurrence of vibration and abnormal noise during motor rotation caused by the influence of the detection error of the rotor position, and the fan motor and compressor in the air conditioner It can be applied as a device for controlling a motor for use.

The circuit block diagram of the motor drive control apparatus which concerns on this embodiment. The figure for demonstrating the concept of the detection error of a rotor position. The flowchart for demonstrating the flow of a series of operation | movement of the motor drive control apparatus which concerns on this embodiment. The figure which shows the waveform of the drive voltage output to a motor by the motor drive control apparatus which concerns on this embodiment, and the electric current supplied to each drive coil of a motor. 5 is a flowchart for explaining a flow of detection error calculation operation performed by the motor drive control device according to the embodiment. The flowchart for demonstrating the flow of calculation operation | movement of the detection error which concerns on other embodiment (b).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor drive control apparatus 2u, 2v, 2w Hall sensor 3 Rotation speed detection part 4 Detection error calculation part 5 Storage part 5a First storage area 5b Second storage area 6 Correction part 7 Drive voltage generation part 8 PWM control part 9 Gate control Voltage generator 10 Output circuit 11 Power source 51 Motor 52 Stator 53 Rotor 100 Motor drive control system

Claims (6)

A motor drive control device (1) for controlling driving of a motor (51) including a stator (52) having a drive coil (Lu, Lv, Lw) and a rotor (53) having a plurality of magnetic poles,
A position detector (2u, 2v, 2w) that detects the magnetic pole of the rotor (53) and outputs a position detection signal (Hu, Hv, Hw) indicating the position of the rotor (53) with respect to the stator (52). )When,
Based on the position detection signals (Hu, Hv, Hw) when the rotation speed of the motor (51) is less than a first predetermined rotation speed, the rotor (53) in the position detection section (2u, 2v, 2w) ) Position detection error calculating section (4),
A correction unit (6) for correcting the position detection signals (Hu, Hv, Hw) when the rotation speed of the motor (51) is equal to or higher than the first predetermined rotation speed, with the detection error;
Generate drive voltages (SU, SV, SW) for driving the motor (51) based on the position detection signals (Hu ′, Hv ′, Hw ′) corrected by the correction unit (6). A drive voltage generator (7) that outputs to the motor (51);
A motor drive control device (1). The detection error calculation unit (4) calculates the detection error during a trial operation of the motor (51).
The motor drive control device (1) according to claim 1. The position detector (2u, 2v, 2w) in the case where the rotational speed of the motor (51) is a second predetermined rotational speed that satisfies a condition that is less than the first predetermined rotational speed, A first storage unit (5a) for storing a first detection interval from when a magnetic pole is detected until the next magnetic pole is detected;
Further comprising
The drive voltage generator (7) is configured to rotate the motor (51) at the second predetermined rotation speed when the detection error is calculated by the detection error calculator (4). (SU, SV, SW) are generated and output to the motor (51),
The detection error calculation unit (4)
When the rotational speed of the motor (51) is substantially equal to the second predetermined rotational speed, the position detector (2u, 2v, 2w) detects the magnetic pole of the rotor (53) and then the magnetic pole. Measure the second detection interval until detecting
The difference between the first detection interval stored in the first storage unit (5a) and the measured second detection interval is defined as the detection error.
The motor drive control device (1) according to claim 1 or 2. When the detection error is calculated by the detection error calculation unit (4), the drive voltage generation unit (7) sets the motor (51) to a third predetermined condition that satisfies the condition of being less than the first predetermined rotation speed. The drive voltage (SU, SV, SW) for rotating at the rotation speed is generated and output to the motor (51),
The detection error calculation unit (4)
When the rotational speed of the motor (51) becomes substantially the third predetermined rotational speed, the position detector (2u, 2v, 2w) detects the magnetic pole of the rotor (53) and then the magnetic pole. Measuring the third detection interval for one rotation of the motor (51) with a mechanical angle, and obtaining an average value of the third detection interval based on the measurement result,
The difference between the obtained average value of the third detection intervals and any one of the third detection intervals is set as the detection error.
The motor drive control device (1) according to claim 1 or 2. A second storage unit (5b) capable of storing the detection error calculated by the detection error calculation unit (4);
Further comprising
The correction unit (6) uses the detection error stored in the second storage unit (5b), and the position when the rotational speed of the motor (51) is equal to or higher than the first predetermined rotational speed. Correct the detection signals (Hu, Hv, Hw),
The motor drive control device (1) according to any one of claims 1 to 4. A sinusoidal current is applied to the motor (51) to which the drive voltages (SU, SV, SW) based on the corrected position detection signals (Hu ′, Hv ′, Hw ′) are output. The
The motor drive control device (1) according to any one of claims 1 to 5.

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