JP2007259558A - Motor control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress uneven torque, and reduce noise in a brushless motor, while averting cost increase. <P>SOLUTION: When steady-state operation of the motor is started, rotation signals of U, V, and W phases are outputted from Hall IC elements 78A to 78C. A motor control device corrects information Tn1 to Ts3 on the period of each magnetic pole of a sensor magnet 76, contained in these signals (period information immediately before) with correction values Hn1 to Hs3. Then the motor control device sets the PWM signal of a predriver circuit 48 (present energization timing), based on the rotation signals Su, Sv, Sw corrected with the correction values. For this reason, even if the magnetic poles of the sensor magnet 76 fluctuate in the direction of rotation, influence due to this fluctuation can be eliminated and the PWM signal of the predriver circuit 48 can be set appropriately. As a result, uneven torque in a motor 16 can be suppressed, and its noise can be reduced. Since it is unnecessary to further strictly set the magnetization position of the magnetic poles of the sensor magnet 76, increase in cost can be averted. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a motor control device that controls the rotational speed of a rotor while detecting the rotational position of the rotor using a Hall IC element or the like.

In general, in order to control the rotation speed of a brushless motor, a sensor magnet (permanent magnet) that rotates integrally with a rotor, and a magnetic sensor such as a plurality of Hall IC elements arranged to face the sensor magnet, Are used. When the brushless motor is configured with a three-phase coil, each of the plurality of magnetic sensors is arranged corresponding to each phase of the three-phase coil. In the control device for driving the brushless motor, the energization timing of the coils of each phase is set based on the detection result of the rotational position of the sensor magnet by each magnetic sensor.
JP 2003-47277 A

  By the way, as described above, the sensor magnet that rotates integrally with the rotor is configured to have a plurality of magnetic poles in the rotation direction. However, in general, the magnetic poles of the sensor magnet are in a state of variation in the rotational direction (that is, the magnetic poles are not uniform in the rotational direction). In particular, the accuracy of the magnetization pitch generally decreases as the number of magnetic poles increases or as the outer diameter of the sensor magnet decreases. Therefore, in this type of brushless motor control device, the energization timing for the coils of each phase is set based on the detection result of the magnetic sensor in a state where the magnetic poles of the sensor magnets vary in the rotational direction. Strictly speaking, the coils of each phase are not energized at an appropriate energization timing. For this reason, torque unevenness occurs in the brushless motor, which may increase noise.

  At this time, in order to energize at a more appropriate energization timing, it is conceivable to set the magnetic pole position of the magnetic pole of the sensor magnet more strictly by increasing the working accuracy. However, if it does in this way, the problem that cost will increase by setting the magnetizing position of the magnetic pole of a sensor magnet still more strictly arises.

  On the other hand, the magnetized position of the magnetic pole of the sensor magnet is unique to each brushless motor and remains unchanged. For this reason, for example, at the time of manufacturing each brushless motor, the magnetic poles of the sensor magnet provided in the brushless motor are stored in advance in a storage device such as an EEPROM, and the coil of each phase is based on this stored information. It is also possible to correct and set the energization timing for. In this way, even when the magnetic poles of the sensor magnet vary in the rotational direction, it is possible to prevent torque unevenness of the brushless motor. However, in this case, generally, a storage device such as an EEPROM is expensive, and a new problem such as an increase in cost due to an increase in the number of work steps in the manufacturing process arises.

  In view of the above-described facts, an object of the present invention is to provide a motor control device that can suppress torque unevenness and reduce noise while avoiding an increase in cost.

In order to solve the above-described problem, the brushless motor control device according to claim 1, an energization circuit configured to energize each of a plurality of windings of the brushless motor at a predetermined energization timing;
A sensor magnet that rotates integrally with the rotor to detect the rotational position of the rotor of the brushless motor that rotates with the magnetic field formed by the plurality of windings, and that has a plurality of position detection magnetic poles in the rotational direction; A rotation sensor disposed opposite to the sensor magnet to detect a change in the magnetic field accompanying the rotation of the sensor magnet, period information for one rotation of the sensor magnet based on a detection result of the rotation sensor, and the sensor magnet Detecting the period information of each magnetic pole when the sensor magnet makes one rotation, and dividing the period information for one rotation of the sensor magnet by the number of magnetic poles of the sensor magnet, Calculate the ideal period information of the magnetic pole, and the ideal period information of each magnetic pole and the sensor magnet make one rotation The difference from the period information of each magnetic pole is calculated and stored as a correction value, and the period information of each magnetic pole of the sensor magnet obtained from the rotation sensor is corrected by the correction value at the start of steady motor operation. Control means for setting energization timing of the energization circuit based on the period information corrected with the correction value.

  In the brushless motor control device according to claim 1, the windings of a plurality of phases constituting the brushless motor are energized by the energization circuit at a predetermined energization timing, and the rotor of the brushless motor is predetermined by the magnetic field formed by these windings. It is rotated at the number of rotations.

  On the other hand, when the rotor rotates, the sensor magnet rotates integrally with the rotor, and a plurality of position detection magnetic poles formed in the rotation direction of the sensor magnet pass through the rotation sensor arranged opposite to the sensor magnet. Thus, a change in the magnetic field accompanying the rotation of the sensor magnet is detected by the rotation sensor.

  Further, the control means detects period information for one rotation of the sensor magnet and period information of each magnetic pole when the sensor magnet makes one rotation based on the detection result of the rotation sensor. Further, in the control means, the period information for one rotation of the sensor magnet is divided by the number of magnetic poles of the sensor magnet, thereby calculating ideal period information of each magnetic pole when the sensor magnet makes one rotation. Further, the control means calculates a difference between the ideal period information of each magnetic pole and the period information of each magnetic pole when the sensor magnet detected as described above makes one rotation, and the calculated value is used as a correction value. Remembered. When actually operating the brushless motor in a steady state, the period information (immediately preceding period information) of each magnetic pole of the sensor magnet obtained from the rotation sensor is corrected with the correction value, and based on the period information corrected with this correction value. The energization timing (current energization timing) of the energization circuit is set.

  Thus, in the brushless motor control device according to claim 1, at the start of steady motor operation, the period information (immediately preceding period information) of each magnetic pole of the sensor magnet obtained from the rotation sensor is corrected with the correction value. The energization timing (current energization timing) of the energization circuit is set based on the period information corrected with the correction value. For this reason, even if the magnetic poles of the sensor magnet are varied in the rotation direction, the influence of the variation can be eliminated and the energization timing can be set appropriately. Thereby, the torque nonuniformity of a brushless motor can be suppressed and noise can be reduced. In addition, since it is not necessary to set the magnetizing position of the magnetic pole of the sensor magnet more strictly, it is possible to avoid an increase in cost.

  The brushless motor control device according to claim 2 is the motor control device according to claim 1, wherein the control means has the sensor magnet at a timing from when the motor is started to when the subsequent steady motor operation starts. The process from detection of period information for one rotation and period information of each magnetic pole when the sensor magnet makes one rotation to calculation of the correction value is performed.

  In the brushless motor control device according to claim 2, the process from the detection of the period information for one rotation of the sensor magnet and the period information of each magnetic pole when the sensor magnet makes one rotation to the calculation of the correction value It is performed at the timing from the time until the start of the subsequent steady motor operation. That is, the above processing is performed every time the brushless motor control device is activated. Therefore, it is not necessary to provide a storage device such as an EEPROM in the brushless motor control device, and to previously store the magnetized positions of the magnetic poles of the sensor magnet provided in the brushless motor when manufacturing each brushless motor. . Therefore, it is not necessary to use a generally expensive device such as an EEPROM for the storage device of the brushless motor control device.

  In the brushless motor control device according to the second aspect, the processing up to the calculation of the correction value is performed before the start of steady motor operation. At this time, when calculating the above correction value together with the energization control at the start of steady motor operation, the burden on the arithmetic processing device such as a microcomputer used in the control device becomes large, and the arithmetic processing device such as the microcomputer It is necessary to use an expensive one having a high processing speed. However, in the brushless motor control apparatus according to the second aspect, since the processing up to the calculation of the correction value is performed before the start of the steady motor operation, the processing amount of the energization control is small or not. In addition, the above-described correction value can be calculated. Therefore, it is not necessary to use an expensive processing unit such as a microcomputer used in the control unit (that is, a control unit) having a high processing speed.

  Thus, in the brushless motor control device according to the second aspect, it is not necessary to use a generally expensive device such as an EEPROM as the storage device, and the arithmetic processing device is also expensive and has a high processing speed. Since it is not necessary to use a thing, it becomes possible to aim at the further avoidance of a cost increase by this.

  The brushless motor control device according to claim 3 is the motor control device according to claim 1 or 2, wherein the control means includes period information for one rotation of the sensor magnet and one rotation of the sensor magnet. The process from the detection of the period information of each magnetic pole to the calculation of the correction value is performed a plurality of times, and the sensor magnet obtained from the rotation sensor with the average value of the plurality of correction values obtained by the plurality of processes The period information of each of the magnetic poles is corrected, and the energization timing of the energization circuit is set based on the period information corrected with the correction value.

  In the brushless motor control device according to claim 3, the processing from the detection of the period information for one rotation of the sensor magnet and the period information of each magnetic pole when the sensor magnet makes one rotation to the calculation of the correction value is performed a plurality of times. Is called. In addition, an average value of a plurality of correction values obtained by the plurality of processes (for example, an average value excluding a maximum value and a minimum value, a value obtained by a majority vote, a median value in a range between a maximum value and a minimum value) Etc.), and the averaged correction value corrects the period information of each magnetic pole of the sensor magnet obtained from the rotation sensor, and the energization timing of the energization circuit is based on the period information corrected by this correction value. Is set. In this way, in the brushless motor control device according to the third aspect, a plurality of correction values are obtained and the plurality of correction values are averaged, so that the calculation accuracy of the correction values can be improved. Therefore, the energization timing of the energization circuit is further optimized.

  The brushless motor control device according to claim 4 is the motor control device according to any one of claims 1 to 3, wherein the control means makes the rotation speed or applied voltage of the brushless motor constant. In this state, the period information for one rotation of the sensor magnet and the period information of each magnetic pole when the sensor magnet makes one rotation are detected based on the detection result of the rotation sensor.

  5. The brushless motor control device according to claim 4, wherein the detection of the period information for one rotation of the sensor magnet based on the detection result of the rotation sensor and the period information of each magnetic pole when the sensor magnet makes one rotation is performed. The number of rotations (rotation period) or applied voltage is constant. Therefore, it is possible to stably detect the period information for one rotation of the sensor magnet based on the detection result of the rotation sensor and the period information of each magnetic pole when the sensor magnet makes one rotation. In particular, as described above, when the process from the detection of the period information for one rotation of the sensor magnet and the period information of each magnetic pole when the sensor magnet rotates once to the calculation of the correction value is performed a plurality of times, the number of rotations (Rotation period) By making the applied voltage constant, averaging processing under the same conditions can be realized, and the calculation accuracy of the correction value can be further improved.

  The brushless motor control device according to claim 5 is the motor control device according to any one of claims 1 to 3, wherein the control means turns off the energization of the brushless motor, and the brushless motor. When the motor is rotating by inertia, detecting period information for one rotation of the sensor magnet and period information of each magnetic pole when the sensor magnet rotates once based on a detection result of the rotation sensor It is characterized by.

  The brushless motor control device according to claim 5, wherein the detection of the period information for one rotation of the sensor magnet based on the detection result of the rotation sensor and the period information of each magnetic pole when the sensor magnet rotates once is performed by the brushless motor. Is performed when the brushless motor is rotating by inertia, that is, when there is no driving force (vibration force) of the brushless motor. Therefore, the influence of the torque unevenness of the brushless motor is eliminated, and the period information for one rotation of the sensor magnet based on the detection result of the rotation sensor and the period information of each magnetic pole when the sensor magnet makes one rotation are detected. (Magnetic pole variation information can be detected accurately). Thereby, the calculation accuracy of the correction value is further improved.

(Outline of configuration of motor actuator 12 for in-vehicle air conditioner)
First, an outline of the configuration of a motor actuator for an in-vehicle air conditioner will be described.

  As shown in FIG. 3, the motor actuator 12 includes a housing 14 in which a brushless motor 16 (hereinafter simply referred to as “motor 16”) and a control board 18 of the motor control device 10 are housed. ing.

  As shown in FIG. 3, the housing 14 is formed in a shallow, substantially box shape with one end opened, and a substantially cylindrical tube portion 34 is integrally formed with the housing 14 at the opening end of the housing 14. Is provided.

  The housing 14 is provided with a substantially cylindrical support portion 36, and a stator 28 is integrally attached to the outer peripheral portion of the support portion 36. The stator 28 includes a core 26 formed by laminating a plurality of core pieces made of a thin silicon steel plate or the like. Further, the core 26 has three-phase coils 30A, 30B as windings. A coil group 30 consisting of 30C is wound. These coils 30 </ b> A to 30 </ b> C are provided so that their electrical phases are shifted by 120 degrees. When these coils 30 </ b> A to 30 </ b> C are alternately energized at a predetermined cycle, a predetermined rotation around the stator 28 is performed. A magnetic field is formed.

  On the other hand, a pair of bearings 38 are fixed inside the support portion 36, and the shaft 20 is coaxially supported by the bearings 38 with respect to the support portion 36 and the cylindrical portion 34 and is rotatable around its own axis. Has been.

  One end of the shaft 20 in the axial direction passes through the cylindrical portion 34, and the air blower provided in the air conditioner main body (not shown) that rotates by receiving the rotational force of the shaft 20 at one end or in the vicinity of the one end. Mechanically connected to the fan.

  Further, the rotor 22 is integrally attached to a portion of the shaft 20 penetrating from the cylindrical portion 34. The rotor 22 is formed in a bottomed cylindrical shape that is coaxial with the cylindrical portion 34 and the support portion 36 that are opened in a direction opposite to the opening direction of the housing 14, and the shaft 20 passes through the upper bottom portion of the rotor 22. is doing.

  A substantially cylindrical magnet 24 is coaxially fixed to the rotor 22 on the inner periphery of the rotor 22. The magnet 24 is formed so that one side in the radial direction is an N pole and the other side is an S pole through its axis, and the magnetic pole is formed around its own axis every predetermined angle (for example, 60 degrees). Are formed so that their polarities change, and a predetermined magnetic field is formed around them.

  The magnet 24 is provided on the outer side of the stator 28 along the radial direction of the support portion 36 so as to face the stator 28. When the coil group 30 described above is energized, a rotating magnetic field is formed around the stator 28. The rotational force around the support portion 36 is generated in the magnet 24 due to the interaction between the rotating magnetic field and the magnetic field formed by the magnet 24, whereby the shaft 20 rotates.

  On the other hand, the control board 18 is disposed on the bottom side of the housing 14 with respect to the stator 28. The control board 18 is provided with printed wiring on at least one of the front surface and the back surface, and a plurality of resistance elements, transistor elements, and further elements such as a microcomputer are appropriately connected through the printed wiring. Yes.

(Outline of configuration of motor control device 10)
Next, a schematic configuration of the motor control device 10 will be described.

  As shown in FIG. 1, the motor control device 10 (control board 18) includes a speed command circuit 42, a power standby circuit 44, a speed control calculation unit 46 as control means, a pre-driver circuit 48 that constitutes an energization circuit, The circuit includes a driver circuit 48 and a three-phase inverter 50 and a booster circuit 52 that constitute an energization circuit.

  The speed command circuit 42 includes various circuits such as a filter circuit and an amplifier circuit, or is configured by an IC having a function equivalent to the configuration including these circuits, such as an instrument panel of a vehicle. Operation signals from one or more operation switches 54 used for ON / OFF of the air conditioner provided in the air conditioner and for switching the air volume can be input.

  The power supply standby circuit 44 is interposed between the speed command circuit 42 and a speed control calculation unit 46 described later, and controls and suppresses a weak current flowing from the power supply 56 to the air conditioner even when the air conditioner is stopped. It is a circuit to do.

  The speed control calculation unit 46 is a microcomputer including a CPU 62, a ROM 64, a RAM 66, a timer 68, and the like. The speed control calculation unit 46 is structurally composed of one or a plurality of integrated circuits, and is functionally a comparator circuit (comparison circuit). ), A reference wave generation circuit such as a triangular wave and a sawtooth wave composed of various circuits such as an amplifier circuit and a multiplication circuit, and a combination thereof, and a PWM (pulse width modulation) circuit function. A PWM signal corresponding to the speed command signal input from the speed command circuit 42 via the circuit 44 is output.

  As shown in FIG. 2, the three-phase inverter 50 includes three N-channel power MOS field effect transistors 70A, 70B, and 70C each serving as an upper switching element (or upper semiconductor element), and lower switching elements. (Or lower semiconductor elements) are provided with three N-channel power MOS field effect transistors 72A, 72B, 72C (hereinafter, these N-channel field effect transistors 70A-70C, 72A-72C are referred to as “ MOSFETs 70A-70C, 72A-72C ").

  Among these MOSFETs 70A to 70C and 72A to 72C, the source of the MOSFET 70A and the drain of the MOSFET 72A are connected to the terminal of the coil 30A. The source of the MOSFET 70B and the drain of the MOSFET 72B are connected to the terminal of the coil 30B, and the source of the MOSFET 70C and the drain of the MOSFET 72C are connected to the terminal of the coil 30C.

  The pre-driver circuit 48 is a circuit interposed between the speed control calculation unit 46 and the three-phase inverter 50 and is connected to the gates of the MOSFETs 70A to 70C and 72A to 72C described above, and is output from the speed control calculation unit 46. Based on the PWM signal thus generated, the switching signals of “HIGH” level or “LOW” level are output to the respective gates of the MOSFETs 70A to 70C and 72A to 72C to the MOSFETs 70A to 70C and 72A to 72C of the three-phase inverter 50. As is well known in the art, the MOSFETs 70A to 70C and 72A to 72C are in the OFF state when a switching signal of “LOW” level is input to the gate, and basically the current from the power source 56 does not flow from the drain to the source. When a “HIGH” level switching signal is input to the gate, the transistor is turned on, and a current from the power source 56 flows from the drain to the source.

  The booster circuit 52 shown in FIG. 1 is a circuit connected to the pre-driver circuit 48, and is used to make the voltage level of the switching signal output to the MOSFETs 70A to 70C shown in FIG. Circuit.

  On the other hand, the motor control device 10 includes a sensor magnet 76 (see FIGS. 3 and 4A) and three Hall IC elements 78A, 78B and 78C (see FIGS. 1 and 4B). Has been.

  As shown in FIG. 3, the sensor magnet 76 is coaxially and integrally fixed to the shaft 20 on the other axial end side of the shaft 20. The sensor magnet 76 is also a permanent magnet, and as shown in FIG. 4A, the N pole magnetic poles 76n1 to 76n3 and the S pole magnetic poles 76s1 to 76s1 are arranged at predetermined angles (for example, 60 degrees) around the axis. 76s3 is a multipole magnet alternately positioned, and a specific magnetic field is formed around the multipole magnet.

  On the other hand, the Hall IC elements 78A to 78C are provided every 20 degrees around the axis of the sensor magnet 76 so as to face the sensor magnet 76, and detect the magnetic force lines constituting the magnetic field of the sensor magnet 76 at each position. To do. Each of these Hall IC elements 78A to 78C is connected to the speed control calculation unit 46 described above.

  In addition, the motor control device 10 includes various sensors such as a current sensor 82, a voltage sensor 84, and a temperature sensor 86. The current sensor 82 detects the current value of the current flowing through the three-phase inverter 50, and the voltage sensor 84 detects the voltage applied to the three-phase inverter 50. Furthermore, the temperature sensor 86 detects the temperature of the three-phase inverter 50 or the like. These various sensors such as the current sensor 82, the voltage sensor 84, and the temperature sensor 86 are connected to the CPU 62 of the speed control calculation unit 46, and a signal corresponding to the detected value is output to the CPU 62, and the current, voltage, temperature Is determined to be normal, and if the sensors 82 to 86 detect any abnormal current, voltage, or temperature, the CPU 62 stops the motor 16.

(Operation of motor actuator 12)
Next, the operation of the motor actuator 12 having the above configuration will be described.

  The motor control device 10 performs drive control of the motor 16 by so-called “complementary PWM control”. Since the complementary PWM control is basically a well-known technique, a detailed description thereof will be omitted and a brief description will be given below.

  In the motor control device 10, when the operation switch 54 is operated to turn the air conditioner on / off or switch the air volume, an operation signal having a predetermined voltage is input from the operation switch 54 to the speed command circuit 42.

  The operation signal input to the speed command circuit 42 is converted into a speed command signal as a set value that can be compared by the CPU 62 of the speed control calculation unit 46 in the speed command circuit 42, and then the speed signal is passed through the power standby circuit 44. It is output to the control calculation unit 46.

  Each of the speed command signal input to the speed control calculation unit 46 and a reference wave such as a triangular wave and a sawtooth wave generated separately by the speed control calculation unit 46 is processed in the same manner as the comparison calculation process in the comparator circuit. Further, a PWM signal as a pulse signal having a pulse width corresponding to the operation command signal level is generated based on the speed command signal and the reference wave, and is output to the pre-driver circuit 48.

  The pre-driver circuit 48 generates a pulse-like switching signal as a drive signal that can turn on / off each of the MOSFETs 70A to 70C and 72A to 72C based on the level and pulse width of the PWM signal together with the booster circuit 52. A switching signal is output to the gates of the MOSFETs 70A to 70C and 72A to 72C of the three-phase inverter 50.

  As described above, each of the MOSFETs 70A to 70C and 72A to 72C is in the OFF state when the input switching signal is at the “LOW” level, and basically cuts off the current from the power source 56 from the drain to the source. If it is “HIGH” level, it is in the ON state, and the current from the power source 56 is allowed to flow from the drain to the source. Here, the switching signal is generated based on the PWM signal, so that any of the MOSFETs 70A to 70C and any of the MOSFETs 72A to 72C are alternately turned on, and the energization waveform is rectified into a rectangular wave. A current flows through the coils 30A to 30C.

  In this way, a predetermined magnetic field is formed around the coils 30 </ b> A to 30 </ b> C, and the magnet 24 rotates due to the interaction between the magnetic field formed by the coils 30 </ b> A to 30 </ b> C and the magnetic field formed by the magnet 24, and is integrated with the magnet 24. The shaft 20 rotates.

  Further, when the shaft 20 rotates, the sensor magnet 76 rotates together. As described above, the sensor magnet 76 forms a multipolar magnet and forms a specific magnetic field around it. However, when the sensor magnet 76 rotates, the magnetic field of the sensor magnet 76 with respect to the periphery of the sensor magnet 76. Fluctuates.

  The fluctuation of the magnetic field around the sensor magnet 76 is a change in the strength of the magnetic lines of force at a specific position around the sensor magnet 76. The magnetic field lines of the magnetic field formed by the sensor magnet 76 are detected by the Hall IC elements 78A to 78C disposed around the sensor magnet 76, and a rotation signal corresponding to the detected strength of the magnetic field lines is speed-controlled from the Hall IC elements 78A to 78C. It is output to the calculation unit 46.

  At this time, as shown in FIG. 8A, when there is no variation in the magnetization of the sensor magnet 76 (the magnetization pitch is uniform), the Hall IC elements 78A to 78C in FIG. There is no error in the period information Tn1 to Ts3 (period information) of each magnetic pole of the sensor magnet 76 included in the output U, V, and W phase rotation signals (see FIG. 8C). On the other hand, as shown in FIG. 4A, when the magnetization of the sensor magnet 76 varies (the magnetization pitch is not uniform), the Hall IC elements 78A to 78A in FIG. Errors En1 to Es3 occur in the period information Tn1 to Ts3 (period information) of each magnetic pole of the sensor magnet 76 included in the U, V, and W phase rotation signals output from 78C (see FIG. 4C). Therefore, in the present embodiment, the speed control calculation unit 46 performs the following process in order to eliminate the influence of the errors En1 to Es3 due to the variation in magnetization of the sensor magnet 76.

  That is, as shown in FIG. 6, the speed control calculation unit 46 holds the rotational speed from the time of starting the motor to the time of starting the subsequent steady motor operation (for example, the operating range of the brushless motor 16 is 800 rpm to In the case of 4000 rpm, the U, V, and W phases output from the Hall IC elements 78A to 78C during the period of 0 to 800 rpm that starts gently (for example, while maintaining the rotation speed for a period that is not noticed by the user) Each rotation signal is detected. At this time, based on the detection results of the Hall IC elements 78A to 78C, as shown in FIG. 4C, the period information Tu, Tv, Tw for one rotation of the sensor magnet 76 and the sensor magnet 76 are one. Period information Tn1 to Ts3 of each magnetic pole 76n1 to 76s3 when rotating is detected and stored for each phase.

  The period information Tu, Tv, Tw and period information Tn1 to Ts3 for each phase are stored in the RAM 66 only while the ignition switch of the vehicle is on, and are reset (erased) when the ignition switch is off. The When the ignition switch is turned on next time and the motor 16 starts to start as described above, the period information Tu, Tv, Tw and the period information Tn1 to Ts3 for each phase are detected and stored in the RAM 66 again. Is done.

  Further, the speed control calculation unit 46 divides the period information Tu, Tv, Tw for one rotation of the sensor magnet 76 by the number of magnetic poles of the sensor magnet 76 (that is, the number of magnetic poles 6), thereby FIG. As shown in Fig. 4, ideal period information Tn1 'to Ts3' of each magnetic pole when the sensor magnet 76 makes one rotation is calculated for each phase, and for each phase, the ideal period information Tn1 'to Ts3' of each magnetic pole. And the difference between the period information Tn1 to Ts3 of each magnetic pole when the sensor magnet 76 makes one rotation is calculated and stored as correction values Hn1 to Hs3.

  That is, when the magnetizing pitch of the sensor magnets 76 is non-uniform, when the motor 16 is rotated at a constant rotation speed, the period information Tn1 to Ts3 of the magnetic poles becomes non-uniform, but the sensor magnets 76 are annular. The period information Tu, Tv, Tw for one rotation (the sum of the period information Tn1 to Ts3 for the number of magnetic poles) is uniform as shown in FIG. Therefore, by dividing the period information Tu, Tv, Tw for one rotation of the sensor magnet 76 by the number of magnetic poles of the sensor magnet 76 (that is, the number of magnetic poles 6), as shown in FIG. The same period information Tn1 ′ to Ts3 ′ (ideal values) as in the case where there is no variation in the magnetization (see FIG. 8 for the period information to be compared) can be obtained. In this embodiment, the difference between the ideal period information Tn1 'to Ts3' of each magnetic pole and the period information Tn1 to Ts3 of each magnetic pole is set as the correction values Hn1 to Hs3 and stored.

  On the other hand, at the start of steady motor operation shown in FIG. 6, each rotation of the U, V, and W phases output from the Hall IC elements 78 </ b> A to 78 </ b> C is performed in the speed control calculation unit 46 as shown in FIG. The period information Tn1 to Ts3 (immediately preceding period information) of each magnetic pole of the sensor magnet 76 included in the signal is sequentially corrected with the correction values Hn1 to Hs3 as shown in FIG. The rotation signals are Su, Sv, and Sw. Further, each of the rotation signals Su, Sv, Sw and the speed command signal described above is subjected to a process equivalent to the comparison operation process in the comparator circuit to obtain a deviation.

  Further, the speed control calculation unit 46 generates a PWM signal (current energization timing) based on the deviation, and the pre-driver circuit 48 performs switching operation of the MOSFETs 70A to 70C and 72A to 72C based on the PWM signal. The rotational speed of the shaft 20 is corrected. Further, as described above, the shaft 20 is connected to the fan of the air conditioner outside the housing 14. For this reason, a fan rotates because the shaft 20 rotates in this way, and it is ventilated from an air conditioner by this.

(Operation and effect of this embodiment)
Next, the operation and effect of this embodiment will be described.

  As described above in detail, in the present embodiment, the period information Tn1 of each magnetic pole of the sensor magnet 76 included in the rotation signals of the U, V, and W phases output from the Hall IC elements 78A to 78C at the start of steady motor operation. ~ Ts3 (previous cycle information) is corrected with the correction values Hn1 to Hs3, and the PWM signal (current energization timing) of the pre-driver circuit 48 is set based on the rotation signals Su, Sv, Sw corrected with these correction values. Is done. For this reason, as shown in FIG. 4A, even if the magnetic poles of the sensor magnet 76 are in a state of variation in the rotational direction, the influence of this variation is eliminated and the PWM signal of the pre-driver circuit 48 is removed. Can be set appropriately. Thereby, torque unevenness of the motor 16 can be suppressed, and noise can be reduced. In addition, since it is not necessary to set the magnetized position of the magnetic pole of the sensor magnet 76 more strictly, it is possible to avoid an increase in cost.

  In the present embodiment, the correction values Hn1 to Hs3 are calculated from the detection of the period information Tu, Tv, Tw for one rotation of the sensor magnet 76 and the period information Tn1 to Ts3 of each magnetic pole when the sensor magnet 76 rotates once. The processes up to are performed at the timing from the time of starting the motor shown in FIG. 6 to the time of starting the subsequent steady operation of the motor. That is, the above processing is performed every time the ignition switch is turned on (every time the motor control device 10 is activated). Therefore, it is not necessary to provide a storage device such as an EEPROM in the motor control device 10 and to previously store the magnetization position of the magnetic pole of the sensor magnet 76 provided in the motor 16 when the motor 16 is manufactured. . Therefore, it is not necessary to use a generally expensive device such as an EEPROM for the storage device of the motor control device 10.

  Moreover, in this embodiment, the process until calculation of the above-mentioned correction value Hn1-Hs3 is performed by the time of a motor steady operation start. At this time, when the above-described correction value is calculated together with the energization control at the start of steady motor operation, the burden on the speed control calculation unit 46 of the motor control device 10 increases, and the processing is performed by the speed control calculation unit 46. It is necessary to use an expensive one with high speed. However, in the present embodiment, the processing up to the calculation of the correction values Hn1 to Hs3 described above is performed before the start of steady motor operation. Therefore, the correction value described above when the processing amount of the energization control is small or absent. Hn1 to Hs3 can be calculated. Therefore, it is not necessary to use an expensive one with a high processing speed for the speed control calculation unit 46 (that is, the control means) of the motor control device 10.

  Thus, in this embodiment, it is not necessary to use a generally expensive device such as an EEPROM as the storage device of the motor control device 10, and the speed control calculation unit 46 is also an expensive device with a high processing speed. Therefore, it is possible to further avoid the cost increase.

  According to the present embodiment, in addition to the above, the following operations and effects are achieved by performing the processing up to the calculation of the correction values Hn1 to Hs3 described above until the start of steady motor operation.

  That is, the timer 68 that counts the period information Tn1 to Ts3 of each magnetic pole when the sensor magnet 76 makes one rotation has a fixed count period. Therefore, as described above, if the period information Tn1 to Ts3 of each magnetic pole when the sensor magnet 76 rotates once when the rotation number of the motor 16 is low, the period information Tn1 to Ts3 of each magnetic pole is detected. Can be increased. Therefore, by increasing the count amount, it is possible to reduce the rounding error when calculating the period information Tn1 to Ts3, and to improve the accuracy.

  Further, the lower the rotational speed of the motor 16, the weaker the driving force (excitation force) of the motor 16. For this reason, as described above, if the process of calculating the correction values Hn1 to Hs3 is performed when the rotational speed of the motor 16 is low, it is difficult for the occupant to feel noise due to torque unevenness before correction. it can.

  In addition, in the case of a system including a power standby circuit 44 (having a standby mode) for reducing the circuit current consumption as much as possible in order to prevent the vehicle battery from going up when the motor 16 is not rotated as in the present embodiment, together with the rotation command information Power is supplied to the speed control calculation unit 46 (microcomputer) to start the program. For this reason, as described above, if the correction values Hn1 to Hs3 are calculated when the rotational speed of the motor 16 is low, when the ROM 64 software of the speed control calculation unit 46 is assembled, The correction value calculation routine described above can be added between the motor control routines, and the change in the ROM 64 software can be minimized.

  Further, as in the present embodiment, in the case of an on-vehicle air conditioner, the adjustment of the rotation speed (applied voltage) of the motor 16 is gently controlled so that the user does not feel uncomfortable. . Therefore, as described above, when the correction values Hn1 to Hs3 are calculated when the rotational speed of the motor 16 is low, the correction values Hn1 to Hn1 are gradually increased while the rotational speed is being increased. The storage of Hs3 can be completed, and the user can be prevented from being noticed. Thereby, it is possible to prevent the user from feeling uncomfortable.

(Modification of this embodiment)
Next, a modification of this embodiment will be described.

  In the above embodiment, the period information Tu, Tv, Tw for one rotation of the sensor magnet 76 and the period information Tn1 to Ts3 of each magnetic pole when the sensor magnet 76 rotates once to the calculation of the correction values Hn1 to Hs3. Although it has been described that the process is performed only once, this process may be performed a plurality of times. In addition, an average value of a plurality of correction values obtained by the plurality of processes (for example, an average value excluding a maximum value and a minimum value, a value obtained by a majority vote, a median value in a range between a maximum value and a minimum value) Etc.), and the averaged correction value is used to calculate the period information Tn1 to Ts3 (the magnetic pole period information Tn1 to Ts3) included in the U, V, and W phase rotation signals output from the Hall IC elements 78A to 78C. The immediately preceding cycle information) may be corrected, and the PWM signal (current energization timing) of the pre-driver circuit 48 may be set based on the cycle information corrected with this correction value. In this way, since a plurality of correction values are obtained and the plurality of correction values are averaged, the calculation accuracy of the correction values can be improved. Therefore, the PWM signal of the pre-driver circuit 48 is also optimized.

  In the above-described embodiment, the detection of the period information Tu, Tv, Tw for one rotation of the sensor magnet 76 and the period information Tn1 to Ts3 of each magnetic pole when the sensor magnet 76 makes one rotation is detected by the number of rotations of the motor 16 ( (Rotation period) or in a state where the applied voltage is constant (while monitoring that the output voltage (rotation period) is constant). By doing so, it is possible to stably detect the period information Tu, Tv, Tw for one rotation of the sensor magnet 76 and the period information Tn1 to Ts3 of each magnetic pole when the sensor magnet 76 makes one rotation. In particular, as described above, the period information Tu, Tv, Tw for one rotation of the sensor magnet 76 and the period information Tn1 to Ts3 of each magnetic pole when the sensor magnet 76 rotates once to the calculation of the correction values Hn1 to Hs3. When the process is performed a plurality of times, by making the rotation speed (rotation cycle) and the applied voltage constant, the average process under the same conditions can be realized, and the calculation accuracy of the correction value can be further improved. .

  In the present embodiment, since the motor 16 is driven from the period information Tn1 to Ts3 before correction and the correction values Hn1 to Hs3 are read, the sensor magnet 76 is being read while the correction values Hn1 to Hs3 are being read. Thus, the motor 16 is driven in a state in which there is an influence of the variation in the magnetization. For this reason, although the influence of variations in magnetization of the sensor magnet 76 can be suppressed as much as possible by calculating the correction values Hn <b> 1 to Hs <b> 3 in a state where the rotational speed of the motor 16 is low, the influence of torque unevenness may remain slightly. Therefore, in order to eliminate the influence, in order to make the motor 16 have no driving force (vibration force), the energization to the motor 16 is turned off immediately before reading the period information Tn1 to Ts3, and the motor 16 is inertial. The period information Tn1 to Ts3 may be detected at the rotation timing.

  In this way, the influence of torque unevenness of the motor 16 is eliminated, the period information Tu, Tv, Tw for one rotation of the sensor magnet 76 and the period information Tn1 of each magnetic pole when the sensor magnet 76 rotates once. Ts3 can be detected (magnetic pole variation information can be accurately detected). Thereby, the calculation accuracy of the correction values Hn1 to Hs3 is further improved. At this time, while the motor 16 rotates by inertia, the number of rotations (rotation period), the applied voltage, and the like are monitored, and the correction values Hn1 to Hs3 are read in a constant state. The calculation accuracy of the correction values Hn1 to Hs3 is further improved.

  In the above embodiment, the correction values Hn1 to Hs3 are calculated from the detection of the period information Tu, Tv, Tw for one rotation of the sensor magnet 76 and the period information Tn1 to Ts3 of each magnetic pole when the sensor magnet 76 rotates once. 6 is performed at the timing from the start of the motor shown in FIG. 6 to the start of the subsequent steady operation of the motor, but in the first rotation (the state where the load of the speed control calculation unit 46 is low) It may also be performed.

It is a block diagram which shows the outline of a structure of the motor control apparatus which concerns on one Embodiment of this invention. It is a block diagram which shows the outline of the relationship between the structure of a three-phase inverter, and circumference | surroundings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially cutaway front sectional view showing a schematic configuration of a brushless motor actuator to which a motor control device according to an embodiment of the present invention is applied. (A) The figure which shows the arrangement configuration of the magnetic pole of the sensor magnet which concerns on one Embodiment of this invention, (b) The figure which shows the arrangement configuration of the Hall IC element which concerns on one Embodiment of this invention, (c) One of this invention The time chart which shows the period information for one rotation of the sensor magnet which concerns on embodiment, and the period information of each magnetic pole when a sensor magnet rotates once, (d) The ideal period information of each magnetic pole when a sensor magnet rotates once It is a time chart which shows. (A) Time chart showing period information of each magnetic pole of the sensor magnet included in each rotation signal of U, V, W phase output from the Hall IC element according to the embodiment of the present invention, (b) of the sensor magnet It is a time chart which shows the rotation signal obtained by correct | amending the period information of each magnetic pole with a correction value. It is explanatory drawing which shows the relationship between the rotation speed of the brushless motor which concerns on one Embodiment of this invention, and elapsed time. It is a time chart which shows the period information (for 3 periods) of the sensor magnet which concerns on one Embodiment of this invention. (A) The figure which shows the arrangement configuration of the magnetic pole of an ideal sensor magnet, (b) The figure which shows the arrangement configuration of a Hall IC element, (c) The period information and sensor magnet for one rotation of the ideal sensor magnet It is a time chart which shows the period information of each magnetic pole when is rotated once.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Motor control apparatus, 12 ... Motor actuator, 14 ... Housing, 16 ... Brushless motor, 18 ... Control board, 20 ... Shaft, 22 ... Rotor, 24 ... Magnet, 26 ... Core, 28 ... Stator, 30A, 30B, 30C ... Coil (winding), 34 ... Tube part, 36 ... Supporting part, 38 ... Bearing, 42 ... Speed command circuit, 44 ... Power supply standby circuit, 46 ... Speed control calculation part (control means), 48 ... Pre-driver circuit ( Energization circuit), 50 ... three-phase inverter (energization circuit), 52 ... booster circuit, 54 ... operation switch, 56 ... power supply, 68 ... timer, 70A, 70B, 70C, 72A, 72B, 72C ... field effect transistor, 74 ... Rotation detector, 76 ... sensor magnet, 76n1 to 76s3 ... magnetic pole, 78A, 78B, 78C ... Hall IC element (rotation sensor) 82 ... current sensor, 84 ... Voltage sensor, 86 ... temperature sensor.

Claims (5)

An energization circuit for energizing each of the plurality of windings of the brushless motor at a predetermined energization timing;
A sensor magnet that rotates integrally with the rotor to detect the rotational position of the rotor of the brushless motor that rotates with the magnetic field formed by the plurality of windings, and that has a plurality of position detection magnetic poles in the rotational direction;
A rotation sensor that is disposed opposite to the sensor magnet and detects a change in a magnetic field accompanying rotation of the sensor magnet;
Based on the detection result of the rotation sensor, the period information for one rotation of the sensor magnet and the period information of the magnetic poles when the sensor magnet makes one rotation are detected, and the period information for one rotation of the sensor magnet. Is divided by the number of magnetic poles of the sensor magnet to calculate ideal period information of each magnetic pole when the sensor magnet makes one revolution, and when the sensor magnet makes one revolution with the ideal period information of each magnetic pole. Is calculated and stored as a correction value, and the periodic information of each magnetic pole of the sensor magnet obtained from the rotation sensor is corrected by the correction value at the start of steady motor operation. Control means for setting energization timing of the energization circuit based on the period information corrected by the value;
A motor control device comprising:   The control means includes the period information of one rotation of the sensor magnet and the period information of the magnetic poles when the sensor magnet makes one rotation at a timing from the start of the motor to the start of subsequent steady operation of the motor. The motor control device according to claim 1, wherein processing from detection to calculation of the correction value is performed.   The control means performs a plurality of processes from detection of period information for one rotation of the sensor magnet and period information of the magnetic poles when the sensor magnet rotates once to calculation of the correction value. The energization timing of the energization circuit is corrected based on the period information corrected by the correction value by correcting the period information of each magnetic pole of the sensor magnet obtained from the rotation sensor by an average value of a plurality of correction values obtained by the processing. The motor control device according to claim 1, wherein the motor control device is set.   The control means is configured such that, with the rotation speed or applied voltage of the brushless motor being constant, the period information for one rotation of the sensor magnet and the sensor magnet rotating once based on the detection result of the rotation sensor. The motor control device according to any one of claims 1 to 3, wherein period information of each magnetic pole is detected.   The control means turns off the power of the brushless motor, and when the brushless motor is rotating by inertia, period information for one rotation of the sensor magnet and the sensor based on the detection result of the rotation sensor 4. The motor control device according to claim 1, wherein period information of each magnetic pole when the magnet makes one rotation is detected. 5.

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