JP3854186B2 - Brushless motor and motor control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to, for example, a brushless motor used for air blowing in an air conditioner of a vehicle and a motor control device such as such a brushless motor.
[0002]
[Prior art]
The air blower drive source in the air conditioner mounted on the vehicle includes, for example, a permanent magnet by passing a current rectified by turning on / off a semiconductor element such as a power transistor provided in the drive circuit to the coil. A brushless motor for rotating the rotor is employed, and the blower is rotated by the rotational driving force of the brushless motor to blow air from the main body of the air conditioner into the vehicle compartment.
[0003]
By the way, the setting method of the commutation timing in the brushless motor is roughly classified into a method based on the rotational position of the rotor detected by a magnetic sensor such as a Hall IC element, and a rotational period of the rotor detected by a photo interrupter or a rotary encoder. There are two types of methods.
[0004]
For example, when the commutation timing of a three-phase brushless motor is detected by detecting the rotational position of the rotor with a magnetic sensor and set based on the detection result, a sensor magnet provided coaxially and integrally with the rotor is used. Around the circumference, at least three magnetic sensors are arranged at predetermined angles. Since the sensor magnet is formed so that the polarities are alternately different along the circumferential direction of the sensor magnet, when the sensor magnet rotates, the magnetic pole of the sensor magnet facing the magnetic sensor changes. Each magnetic sensor detects the opposing magnetic poles, the rotational position of the rotor is detected by the combination of the magnetic poles of the sensor magnet detected by each magnetic sensor, and the commutation timing is adjusted according to the change in the combination of magnetic poles detected by each magnetic sensor. By changing it, a rotating magnetic field is formed around the coil.
[0005]
On the other hand, in the method based on the rotation period of the rotor detected by the photo interrupter or rotary encoder, the so-called so-called rotational position of the rotor is subdivided for each phase angle based on the rotation period of the rotor detected by the photo interrupter or rotary encoder. PWM (Pulse Width Modulation) control is performed, thereby causing a current to flow through each coil with an arbitrary energization waveform such as a trapezoidal wave or a sine wave to generate a rotating magnetic field.
[0006]
Such a method based on the rotation cycle has an advantage that torque ripple can be reduced as compared with a method of performing rectification based on the rotational position of the rotor detected by the magnetic sensor. On the other hand, means for detecting the rotation period, such as a photo interrupter or a rotary encoder, is relatively expensive, which is a disadvantage from the viewpoint of cost reduction.
[0007]
Therefore, a method of counting with a timer of a microcomputer or the like during one rotation of the rotor without using expensive means such as a photo interrupter or a rotary encoder can be considered for detecting the rotation period of the rotor as described above.
[0008]
That is, the rotational position detection by the magnetic sensor has a structure in which the magnetic sensor detects the magnetic poles of the permanent magnets facing each other. Therefore, if the total number of magnetic poles (the total number of N poles and S poles) along the circumferential direction of the rotor is known, it is possible to detect that the rotor has made one rotation from the number of changes in the detection results of the magnetic sensor. Here, if counting by the timer is started when the detection result of the magnetic sensor has changed, the count number by the timer when the detection result by the magnetic sensor has changed by the total number of magnetic poles of the permanent magnet is the rotor cycle. By using the rotor rotation cycle (number of counts) obtained in this way, the same effect as when using a photo interrupter or a rotary encoder can be obtained as a result. .
[0009]
[Problems to be solved by the invention]
As described above, when the rotation period of the rotor is detected based on the change in the detection result of the magnetic sensor, the energization control based on the rotation position detection result of the rotor by the plurality of magnetic sensors and the rotation of the rotor Both energization control based on the cycle detection result is possible. For example, a configuration in which the energization control method is appropriately switched according to the state of the rotor, such as the rotational speed of the rotor, can be considered.
[0010]
However, when energization control is performed based on the detection result patterns of a plurality of magnetic sensors, the energization waveform of the current flowing in each coil becomes a square wave, whereas when based on the rotation period as described above, , Trapezoidal wave or sine wave.
[0011]
As described above, if the energization waveform differs depending on the energization control method, output torque fluctuations and chattering occur due to the difference in waveform when the energization control method is switched. It is possible that abnormal noise occurs.
[0012]
In view of the above facts, an object of the present invention is to provide a brushless motor and a motor control device that can prevent or reduce the occurrence of fluctuations in output torque, chattering, and the like even when switching to control with different energization waveforms.
[0013]
[Means for Solving the Problems]
  The brushless motor according to claim 1 includes a stator having a plurality of coils that form a predetermined magnetic field around the energized state, a permanent magnet, and the magnetic field formed by the coils of the plurality of phases and the permanent magnet A rotor that rotates with a rotational force generated by the interaction with the magnetic field to be formed; a rotational position detector that detects a rotational position of the rotor and outputs a position detection signal based on the detected rotational position; A period detection means for detecting a period of the child and outputting a period detection signal based on the detected period; a first control signal having a predetermined waveform based on the position detection signal; and the first detection signal based on the period detection signal; Waveform different from control signalThus, the energization waveform when the coil is finally energized becomes a non-target energization waveform.When a control signal generating means capable of generating both of the second control signals and one of the first control signal and the second control signal is output and a specific condition is satisfiedBeforeEither one of the control signalsWhatThe control means for switching to the other control signal and outputting, and each of the coils of the plurality of phases is energized or energized at a timing based on the first control signal or the second control signal output from the control means. Rectifying means for releasing,Furthermore, when switching the control signal output by the control means, the control means is configured to apply an energization waveform when the coil is energized based on any one of the output control signals. Based on the other control signal, the deviation from the energization waveform when the coil is energized is reduced, or the other control signal is corrected based on the one of the control signals so as to eliminate the deviation. At the same time, based on one of the other control signals, the deviation between the time center from the start of energization to the stop of energization when the coil is energized and the center of the current effective area of the energization waveform is corrected. Therefore, it is characterized in that either one of the other control signals is corrected based on any one of the control signals output immediately before the switching.
[0014]
In the brushless motor having the above-described configuration, when a current is supplied with a predetermined energization waveform to a plurality of coils provided with a rectifier in the stator, a predetermined magnetic field is formed around the coil. A rotational force is generated by the interaction between the magnetic field formed by this coil and the magnetic field formed by the permanent magnet provided on the rotor, and the rotor rotates at a predetermined speed by this rotational force.
[0015]
On the other hand, the rotational position of the rotating rotor is detected by the rotational position detecting means, and a position detection signal corresponding to the rotational position of the rotor is output from the rotational position detecting means, and the rotational period of the rotating rotor is periodic. A period detection signal detected by the detection means and corresponding to the rotation period of the rotor is output from the period detection means.
[0016]
The position detection signal output from the rotational position detection means and the period detection signal output from the period detection means are input to the control means. The control signal generating means can generate the first control signal based on the position detection signal and can generate the second control signal based on the period detection signal.
[0017]
One of the first control signal and the second control signal generated by the control signal generation unit is output via the control unit. One of the control signals output from the control means is input to the rectifying means, and the rectifying means has a timing based on one of the input control signals (that is, the first control signal or the second control signal). Each of the above-described plural-phase coils is brought into an energized state or a de-energized state.
[0018]
By the way, in this brushless motor, when a specific condition is satisfied, the control means switches the control signal to be output from any one of the control signals so far to any one of the other control signals.
[0019]
Here, since the signal waveforms of the first control signal and the second control signal are different from each other, the energization and de-energization timing is determined depending on whether the first control signal or the second control signal is input to the rectifier. As a result, the energization waveform of the current flowing through each coil changes between when the first control signal is input to the rectifying means and when the second control signal is input.
[0020]
In this way, by changing the energization waveform of the current flowing in each coil, it is possible to energize each coil at a more appropriate timing according to the state of the rotor (for example, the rotational speed of the rotor), and so on. Generation can be suppressed or prevented, or power consumption can be reduced.
[0021]
By the way, as described above, the signal waveform differs between the first control signal and the second control signal, and as a result, the energization waveform of the signal input to the rectifying means changes between the first control signal and the second control signal.
[0022]
  Here, in this brushless motor, when switching the control signal output by the control means as described above,The difference between the energization waveform when the coil is energized based on the first control signal and the left-right asymmetric energization waveform when the coil is energized based on the second control signal is small, or such a divergence So that there is noBased on any one of the control signals that have been output so far, the signal level, phase, and the like of the other control signal that is output after switching are corrected.Furthermore, the deviation between the time center from the start of energization to the stop of energization and the center of the current effective area of the energization waveform when the rectifier energizes the coil based on one of the other control signals is corrected. The other control signal is corrected based on one of the control signals output immediately before the switching.Thus, based on the output of the brushless motor when the rectifying means energizes or deenergizes each coil at the timing based on one of the control signals immediately before switching, and on the other of the control signals after switching. Deviations from the output of the brushless motor when the rectifiers are energized or de-energized at each timing at the timing are corrected (that is, the deviations are eliminated or reduced), and torque fluctuations and chattering due to such deviations are corrected. Etc. are prevented or reduced.
[0023]
In the present invention, when a specific condition is satisfied, one of the other control signals is corrected based on one of the control signals output by the control means, and the correction is made from either one of the control signals. The control signal is switched to one of the other control signals and output. Here, the control means may be configured to switch the control signal immediately after the control means determines that the specific condition is satisfied, for example, when the specific condition is satisfied. Even if the control means makes a determination, the current state is suspended without switching the control signal until the determination continues for a predetermined number of times, and when the determination continues for a predetermined number of times, the control means switches the control signal. It is good also as a structure to perform.
[0024]
In this way, when the control means switches after the control means determines that the specific condition is continued a predetermined number of times, the control signal is switched due to erroneous determination caused by noise included in the signal. As a result, it is possible to prevent or reduce torque fluctuations and chattering due to inadvertent control signal switching.
[0025]
Although not particularly mentioned in the present invention, not only the rotational position of the rotor but also the rotational direction is detected by the rotational position detecting means or other rotational direction detecting means, and the rotational direction of the rotor is also controlled by the control signal. It may be added as one of the determination conditions for performing the switching. As described above, when the rotation direction of the rotor is set as one of the determination conditions for switching the control signal, for example, the rotor reverses due to some external force acting on the rotor, and this reverse rotation is rotated. When the position detection means or other rotation direction detection means detects, the rectification means is controlled at a timing based on the first control signal. Thereby, rotation control of a rotor can respond | correspond accurately to the rapid rotation speed of a rotor, and the change of a rotation direction.
[0026]
A brushless motor according to a second aspect of the present invention is the brushless motor according to the first aspect of the present invention, wherein each of the brushless motors is disposed around the rotor and is provided integrally with the permanent magnet or the rotor constituting the rotor. The rotational position detecting means includes a plurality of magnetic sensors for detecting the magnetic poles of the permanent magnet, and a predetermined rotation based on a detection signal output from any one of the plurality of magnetic sensors. The period detecting means includes a timer means for counting from a position until the rotor makes one rotation, and the period detecting signal is a counting signal based on a count value of the timer means. It is said.
[0027]
In the brassless motor having the above configuration, a plurality of magnetic sensors constituting the rotational position detecting means are arranged around the rotor. When the rotor rotates, a permanent magnet constituting the rotor or another permanent magnet provided integrally with the rotor separately from the permanent magnet rotates, and the magnetic poles of the permanent magnets facing the plurality of magnetic sensors change. . The magnetic sensor outputs a detection signal corresponding to the detected magnetic pole, and the rotational position of the rotor is detected by a combination of the detection signals. In the control signal generation means, the first control signal is generated according to the combination pattern of the detection signals output from these magnetic sensors.
[0028]
On the other hand, since the magnetic sensor is configured to detect the magnetic poles of the rotating permanent magnet, if the number of magnetic poles of the permanent magnet (total of N poles and S poles) is known, output from any one of the magnetic sensors. It is possible to detect that the rotor has made one rotation based on the number of detection signal switching. This brushless motor is provided with a timer means that constitutes a period detection means, and counts until the rotor makes one revolution from a predetermined rotational position based on the detection signal from any one of the magnetic sensors described above ( Counting is performed, and the cycle of the rotor is obtained from this count value (that is, the count signal corresponding to the count value in the timer means becomes the cycle detection signal). The control signal generating means generates a second control signal based on the count signal from the timer means.
[0029]
Here, the first control signal depends on the pattern of the detection signal from each magnetic sensor, whereas the second control signal depends on the count value until the rotor makes one revolution. Therefore, when the rotation speed of the rotor changes, the current flowing through the coil can be controlled by the first control signal, and when the change in the rotor speed is relatively small, the second control signal makes it finer. Current control can be performed.
[0030]
A brushless motor according to a third aspect of the present invention is the brushless motor according to the second aspect of the present invention, wherein the timer means has an upper limit value for counting, and a state where the count value by the timer means is within the upper limit value is set as the specific condition. In addition, the control signal output from the control means when the specific condition is satisfied is switched from the first control signal to the second control signal.
[0031]
In the brassless motor having the above configuration, since the timer means has an upper limit value for counting, for example, if the rotor does not rotate once even if the count value in the timer means reaches the upper limit value, in this case Even if the control signal generation unit generates the second control signal based on the count signal output from the timer unit, the rectification timing in the rectification unit based on the second control signal (that is, energization or de-energization of each coil) Is not appropriate.
[0032]
Therefore, in this brushless motor, if the rotor does not rotate once even when the count value of the timer means reaches the upper limit value, the first control signal is output from the control means.
[0033]
On the other hand, if the count signal output from the timer means is less than or equal to the upper limit value that can be counted by the timer means, the control signal output from the control means is switched from the first control signal to the second control signal. In addition, at the time of this switching, the second control signal is corrected based on the first control signal that has been output as described above, so that the second smooth operation can be performed while preventing or reducing torque fluctuations, chattering, and the like. Switching to rectification based on the control signal.
[0034]
A brushless motor according to a fourth aspect of the present invention is the brushless motor according to the second or third aspect, wherein the control means determines whether or not the timer means is operating normally based on the counting signal, and the timer The state determined by the control means that the means is operating normally is set as the specific condition, and the control signal output by the control means when the specific condition is satisfied is determined from the first control signal. Switching to the second control signal is a feature.
[0035]
In the brassless motor having the above configuration, when the count signal is output from the timer means, the count signal is input to the control signal generating means to be used for generation of the second control signal, and is also input to the control means to receive the timer means. Whether or not is operating normally is determined.
[0036]
Here, for example, when the count of the timer means does not operate normally due to an overflow or the like, even if the control signal generating means generates the second control signal based on the count signal output from the timer means The rectification timing in the rectification means based on the second control signal (that is, the timing of energization or deenergization of each coil) is not appropriate.
[0037]
Therefore, in this brushless motor, when the control means determines that the timer means is not operating normally, the first control signal is output from the control means.
[0038]
On the other hand, when the control means determines that the timer means is operating normally, the control signal output from the control means is switched from the first control signal to the second control signal. In addition, at the time of this switching, the second control signal is corrected based on the first control signal that has been output as described above, so that the second smooth operation can be performed while preventing or reducing torque fluctuations, chattering, and the like. Switching to rectification based on the control signal.
[0039]
The brushless motor according to a fifth aspect of the present invention is the brushless motor according to any one of the first to fourth aspects, wherein an energization waveform of a current flowing through each of the coils of the plurality of phases is based on the first control signal. A square wave that is energized or de-energized based on the magnetic pole positions of the permanent magnets detected by the plurality of magnetic sensors, and the energized waveform based on the second control signal is energized at the phase of the rotor. It is characterized by trapezoidal waves with different levels.
[0040]
In the brassless motor having the above-described configuration, when the first control signal is output from the control means and the rectifying means energizes and deenergizes each coil based on the first control signal, The energization waveform of the flowing current is a square wave.
[0041]
On the other hand, when a second control signal is output from the control means, and the rectifying means performs energization and de-energization to each coil based on the second control signal, the energization waveform of the current flowing through each coil at this time is It becomes a trapezoidal wave.
[0042]
As described above, in the brushless motor, the energization waveform in each coil is different between when the first control signal is output and when the second control signal is output. If they are the same, the output of the brushless motor changes at the time of switching.
[0043]
However, in the brushless motor, as described above, when one of the first control signal and the second control signal is switched to the other control signal, one of the signals output immediately before the switching is output. Since one of the other control signals is corrected based on this control signal, an output change at the time of switching is prevented or reduced.
[0044]
A brushless motor according to a sixth aspect is the present invention according to any one of the first to fifth aspects, wherein the input signal based on the period detection signal is compared with a reference wave having a predetermined waveform, and the input signal The control signal generating means generates the second control signal having a pulse width that differs depending on the level of the first control signal, and outputs a control signal output from the first control signal when the specific condition is satisfied from the first control signal. And switching to two control signals, and correcting the duty ratio of the second control signal based on the first control signal at the time of the switching.
[0045]
In the brassless motor having the above configuration, when an input signal based on the period detection signal is input to the control signal generating means, the input signal is compared with a reference wave having a predetermined waveform such as a triangular wave or a sawtooth wave, and the level of the input signal In response to this, a pulse signal having a different pulse width is generated as the second control signal. Therefore, basically, since the rectification means energizes or deenergizes each coil at the timing based on the pulse width (duty ratio) of the second control signal, the rectification timing can be set relatively finely.
[0046]
Here, in this brushless motor, at the time of the above switching, the duty ratio of the second control signal output after switching is corrected based on the first control signal that has been output so far.
[0047]
In this way, by correcting the duty ratio of the second control signal, the energization level of the energization waveform of the current flowing through each coil is increased or decreased. The increase / decrease of the energization level corrects the deviation of the output of the brushless motor before and after switching (that is, the deviation is eliminated or reduced), and torque fluctuation and chattering caused by such deviation are prevented or reduced. Is done.
[0048]
A brushless motor according to a seventh aspect of the present invention is the brushless motor according to any one of the first to sixth aspects, wherein the control means is configured to perform the control based on the control signal output immediately before the switching. It is characterized in that the phase of one of the other control signals is corrected.
[0049]
In the brassless motor having the above configuration, when the control means switches the control signal to be output from one of the control signals to any one of the other control signals, the control means changes the control signal to any one of the control signals output immediately before the switching. Based on this, the phase of one of the other control signals is corrected.
[0050]
Therefore, in this brushless motor, the timing of the energization start and de-energization by the rectifying means changes due to the switching, but this change in timing corrects the so-called `` apparent phase '' deviation, and the `` apparent phase '' Torque fluctuations, chattering, and the like due to the deviation are prevented or reduced.
[0051]
  The present invention according to claim 8 includes a stator having a plurality of phase coils that form a predetermined magnetic field in the energized state and a permanent magnet, and the magnetic field formed by the plurality of phase coils and the permanent magnet include A rotor that rotates with a rotational force generated by the interaction with the magnetic field to be formed; a rotational position detector that detects a rotational position of the rotor and outputs a position detection signal based on the detected rotational position; A period detection means for detecting a period of the child and outputting a period detection signal based on the detected period; a first control signal having a predetermined waveform based on the position detection signal; and the first detection signal based on the period detection signal; Waveform different from control signalThus, the energization waveform when the coil is finally energized becomes a non-target energization waveform.When a control signal generating means capable of generating both of the second control signals and one of the first control signal and the second control signal is output and a specific condition is satisfiedBeforeEither one of the control signalsWhatA control means for switching to and outputting the other control signal, and each of the coils of the plurality of phases is energized or energized at a timing based on the first control signal or the second control signal output from the control means. Rectifying means for releasing,Furthermore, when switching the control signal output by the control means, the control means is configured to apply an energization waveform when the coil is energized based on any one of the output control signals. Based on the other control signal, the deviation from the energization waveform when the coil is energized is reduced, or the other control signal is corrected based on the one of the control signals so as to eliminate the deviation. At the same time, based on one of the other control signals, the deviation between the time center from the start of energization to the stop of energization when the coil is energized and the center of the current effective area of the energization waveform is corrected. Therefore, based on the one of the control signals output immediately before the switching, correct one of the other control signals,It is characterized by that.
[0052]
In the motor control device having the above-described configuration, when the rectifying means passes a current with a predetermined energization waveform to the plurality of coils, a predetermined magnetic field is formed around the coil. A rotational force is generated by the interaction between the magnetic field formed by the coil and the magnetic field formed by the permanent magnet, and the rotor rotates at a predetermined speed by the rotational force.
[0053]
On the other hand, the rotational position of the rotating rotor is detected by the rotational position detecting means, and a position detection signal corresponding to the rotational position of the rotor is output from the rotational position detecting means, and the rotational period of the rotating rotor is periodic. A period detection signal detected by the detection means and corresponding to the rotation period of the rotor is output from the period detection means.
[0054]
The position detection signal output from the rotational position detection means and the period detection signal output from the period detection means are input to the control means. The control signal generating means can generate the first control signal based on the position detection signal and can generate the second control signal based on the period detection signal.
[0055]
One of the first control signal and the second control signal generated by the control signal generation means is output via the control means. One of the control signals output from the control means is input to the rectifying means, and the rectifying means has a timing based on one of the input control signals (that is, the first control signal or the second control signal). Each of the above-described plural-phase coils is brought into an energized state or a de-energized state.
[0056]
By the way, in this motor control device, when a specific condition is satisfied, the control means switches the control signal to be output from any one of the control signals so far to any one of the other control signals.
[0057]
Here, since the signal waveforms of the first control signal and the second control signal are different from each other, the energization and de-energization timing is determined depending on whether the first control signal or the second control signal is input to the rectifier. As a result, the energization waveform of the current flowing through each coil changes between when the first control signal is input to the rectifying means and when the second control signal is input.
[0058]
In this way, by changing the energization waveform of the current flowing in each coil, it is possible to energize each coil at a more appropriate timing according to the state of the rotor (for example, the rotational speed of the rotor), and so on. Generation can be suppressed or prevented, or power consumption can be reduced.
[0059]
By the way, as described above, the signal waveform differs between the first control signal and the second control signal, and as a result, the energization waveform of the signal input to the rectifying means changes between the first control signal and the second control signal.
[0060]
  Here, in this motor control device, when switching the control signal output by the control means as described above,The difference between the energization waveform when the coil is energized based on the first control signal and the left-right asymmetric energization waveform when the coil is energized based on the second control signal is small, or such a divergence So that there is noBased on any one of the control signals that have been output so far, the signal level, phase, and the like of the other control signal that is output after switching are corrected.Furthermore, the deviation between the time center from the start of energization to the stop of energization and the center of the current effective area of the energization waveform when the rectifier energizes the coil based on one of the other control signals is corrected. The other control signal is corrected based on one of the control signals output immediately before the switching.As a result, the output of the motor control device when the rectifier is energized or de-energized to each coil at the timing based on one of the control signals immediately before switching, and the other control signal after switching. The deviation from the output of the motor control device when the rectifier is energized or de-energized to each coil at the timing based on the correction is corrected (that is, the deviation is eliminated or reduced), and the torque fluctuation caused by such deviation And chattering are prevented or reduced.
[0061]
DETAILED DESCRIPTION OF THE INVENTION
<Configuration of First Embodiment>
(Outline of configuration of brushless motor 12 for in-vehicle air conditioner)
FIG. 5 shows a front sectional view in which the brushless motor 12 for an in-vehicle air conditioner provided with the motor control device 10 according to the first embodiment of the present invention is partially broken.
[0062]
As shown in this figure, the brushless motor 12 includes a housing 14 in which a drive unit 16 and a control board 18 of the motor control device 10 are accommodated.
[0063]
The housing 14 is formed in a shallow, substantially box shape with one end opened, and a substantially cylindrical tube portion 34 is provided integrally with the housing 14 at the open end of the housing 14.
[0064]
The housing 14 is provided with a substantially cylindrical support portion 36, and a stator 28 as a stator 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 30U, 30V, 30W each serving as a winding. The coil group 30 (refer FIG. 1) which consists of is wound. These coils 30U to 30W are provided so that their electrical phases are shifted by 120 degrees. When these coils 30U to 30W are alternately energized or de-energized at a predetermined timing, around the stator 28, A predetermined rotating magnetic field is formed.
[0065]
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.
[0066]
One end of the shaft 20 in the axial direction penetrates the cylindrical portion 34, and a fan for air blowing provided in an air conditioner main body (not shown) that rotates by receiving the rotational force of the shaft 20 at one end portion or in the vicinity of the one end portion. Mechanically connected to
[0067]
Further, a rotor 22 as a rotor is integrally attached to a portion penetrating from the cylindrical portion 34 of the shaft 20. 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. ing.
[0068]
A substantially cylindrical magnet 24 as a permanent magnet is coaxially fixed to the rotor 22 on the inner peripheral portion 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 at predetermined angles (for example, 60 degrees). Are formed so that their polarities change, and a predetermined magnetic field is formed around them.
[0069]
The magnet 24 is provided on the outside of the stator 28 along the radial direction of the support portion 36 so as to face the stator 28. When the above-described coil group 30 is energized and 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.
[0070]
On the other hand, as shown in FIG. 3, the control board 18 is disposed on the bottom side of the housing 14 relative 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. .
[0071]
(Outline of configuration of motor control device 10)
Next, an outline of the configuration of the control board 18, that is, an outline of the configuration of the motor control device 10 will be described with reference to FIGS.
[0072]
As shown in FIG. 1, the motor control device 10 includes a rotation detection device 40 as a rotation position detection unit.
[0073]
As shown in FIG. 5, the rotation detection device 40 includes a sensor magnet 42. The sensor magnet 42 is fixed coaxially and integrally to the shaft 20 on the other axial end side of the shaft 20. The sensor magnet 42 is also a permanent magnet, and is a multipolar magnet in which N poles and S poles are alternately positioned at predetermined angles (for example, 60 degrees) around its axis, and a specific magnetic field is provided around the magnet. Form.
[0074]
As shown in FIG. 1, on the side of the sensor magnet 42, a period detecting means is configured, and the Hall IC element 44 </ b> U that forms the rotation detecting device 40 together with the sensor magnet 42, and the rotation detection together with the sensor magnet 42. Hall IC elements 44V and 44W constituting the device 40 are provided.
[0075]
These Hall IC elements 44U to 44W are provided every 120 degrees around the axis of the sensor magnet 42 on the outer side in the radial direction of the sensor magnet 42, and detect magnetic lines that constitute the magnetic field of the sensor magnet 42 at each position. To do.
[0076]
On the other hand, the control board 18 constituting the motor control device 10 includes a speed command circuit 46, a power supply standby circuit 48, a speed control calculation unit 50, a pre-driver circuit 52, a three-phase inverter 54 as a rectifier, and a booster circuit 56. Is provided.
[0077]
The speed command circuit 46 is configured by various circuits such as a filter circuit and an amplifier circuit, or an IC chip or a microcomputer having a function equivalent to the configuration including these circuits. For example, the speed command circuit 46 is provided in an instrument panel of a vehicle. Operation signals are input from one or more operation switches 58 that are used for turning on / off the air conditioner and switching the air volume.
[0078]
The power standby circuit 48 is interposed between the speed command circuit 46 and a speed control calculation unit 50 described later, and controls and suppresses a weak current flowing from the power supply 60 to the air conditioner even when the air conditioner is stopped. is doing.
[0079]
The speed control calculation unit 50 is a microcomputer including a CPU 62, a ROM 64, a RAM 66, a timer 68 as a timer means, and the like, and is structurally composed of one or a plurality of integrated circuits, and is functionally a comparator. It is composed of various arithmetic circuits such as a circuit (comparison circuit), an amplifier circuit, and a multiplier circuit.
[0080]
Here, FIGS. 3 and 4 are block diagrams showing the CPU 62 constituting the speed control calculation unit 50 from the functional aspect. Note that, in these drawings, each unit is a case where each process in the CPU 62 is considered for each function, and actually, a comparison circuit and an integration circuit that perform a process corresponding to the function of each unit as a result. These are constituted by various arithmetic circuits.
[0081]
As shown in FIG. 3, the CPU 62 includes a speed comparison unit 70. The speed command signal V output from the speed command circuit 46 described above is input to the speed comparison unit 70 via the power standby circuit 48.
[0082]
The speed comparison unit 70 is connected to the RAM 66 and the ROM 64 and is connected to the Hall IC elements 44U to 44W described above, and the position detection signals D1 and D2 output from the Hall IC elements 44U to 44W, respectively. , D3 is input.
[0083]
Furthermore, the speed comparison unit 70 determines the rotational position of the sensor magnet 42 based on the patterns (combinations) of the position detection signals D1 to D3 from the Hall IC elements 44U to 44W. Further, the speed comparison unit 70 compares the rotational position of the sensor magnet 42, that is, the actual rotational position of the rotor 22 with the rotational position of the rotor 22 on the setting based on the speed command signal V from the speed command circuit 46. Then, the deviation between this set value and the actual rotational position is obtained, and a signal corresponding to this deviation is output.
[0084]
The control signal generation unit 74 constituting the control signal generation unit generates a pulse signal P1 having a constant duty ratio as a first control signal based on the signal corresponding to the deviation output from the speed comparison unit 70. . This pulse signal P1 is input to the pre-driver circuit 52 via the output control unit 76 constituting the control means.
[0085]
As shown in FIG. 2, the pre-driver circuit 52 is connected to gate terminals of field effect transistors (hereinafter referred to as “MOSFETs”) 78U, 78V, 78W, 80U, 80V, and 80W that constitute the three-phase inverter 54. The switching signal S1 is generated based on the pulse signal P1 output from the control signal generation unit 74 via the output control unit 76, and this switching signal is output to the gate terminals of the MOSFETs 78U to 78W and 80U to 80W. .
[0086]
As is conventionally known, the MOSFETs 78U to 78W and 80U to 80W are basically in an “OFF” state when a “LOW” level switching signal is input to the gate terminal, so that a current from the power supply 60 is basically transferred from the drain terminal to the source terminal. Although it does not flow, when the switching signal S1 of “HIGH” level is input to the gate terminal, it becomes “ON” state, and the current from the power supply 60 flows from the drain terminal to the source terminal.
[0087]
Among these MOSFETs 78U to 78W and 80U to 80W, the source terminal of the MOSFET 78U and the drain terminal of the MOSFET 80U are connected to the terminal of the coil 30U. The source terminal of the MOSFET 78V and the drain terminal of the MOSFET 80V are connected to the terminal of the coil 30V, and the source terminal of the MOSFET 78W and the drain terminal of the MOSFET 80W are connected to the terminal of the coil 30W.
[0088]
The booster circuit 56 is a circuit connected to the pre-driver circuit 52, and makes the voltage level of the switching signal S1 sent to the MOSFETs 78U to 78W higher than the voltage level of the power supply 60.
[0089]
On the other hand, as shown in FIG. 4, the CPU 62 constituting the speed control calculation unit 50 includes a cycle calculation unit 82. The period calculation unit 82 is connected to the RAM 66 and the ROM 64, and is also connected to the timer 68 and the Hall IC element 44U.
[0090]
As described above, the Hall IC element 44U detects the polarity (N pole or S pole) of the opposing sensor magnet 42 by detecting the magnetism of the sensor magnet 42. Here, since the sensor magnet 42 is formed so that the north pole and the south pole are alternately positioned along the circumferential direction, the pole of the sensor magnet 42 is provided while the sensor magnet 42 rotates once. The polarity detected by the Hall IC element 44U is switched by the number (the total number of N poles and S poles). Therefore, when the polarity detected by the Hall IC element 44U by the number of poles of the sensor magnet 42 is switched, it is possible to detect that the sensor magnet 42 has made one revolution, that is, the rotor 22 has made one revolution.
[0091]
In the period calculation unit 82, the timer 68 starts counting (counting) at the same time when the position detection signal D1 corresponding to the specific polarity from the Hall IC element 44U is input. Further, the period calculation unit 82 causes the timer 68 to count (count) until it detects that the sensor magnet 42 has made one rotation based on a signal from the Hall IC element 44U, and until the sensor magnet 42 makes one rotation. The cycle of the sensor magnet 42, that is, the rotation cycle T of the rotor 22 is calculated from the required count number (count value) N. Further, the period calculation unit 82 sets a division value Tn obtained by dividing the rotation period T into, for example, an integral multiple of 6.
[0092]
The division value Tn set by the period calculation unit 82 is input to the input signal generation unit 84. The input signal generation unit 84 obtains a deviation between the rotation cycle Ts on the setting of the brushless motor 12 based on the speed command signal V output from the speed command circuit 46 and the actual rotation cycle T based on the divided value Tn. An input signal M based on the deviation is generated and output.
[0093]
The input signal M output from the input signal generation unit 84 is input to the comparison unit 88 via the correction calculation unit 86 constituting the control means. The comparison unit 88 compares the input signal M from the input signal generation unit 84 with the triangular wave Tr as the reference wave output from the triangular wave generation unit 90, and the PWM signal that constitutes the control signal generation unit based on the comparison result The generation unit 92 generates the PWM signal P2 as the second control signal.
[0094]
Here, the PWM signal P2 generated by the PWM signal generation unit 92 is different from the pulse signal P1 generated by the control signal generation unit 74 in terms of generation reference and process, and therefore has a waveform (pulse width). (Duty ratio) is different. The PWM signal generation unit 92 outputs the PWM signal P <b> 2 generated via the output control unit 76. The output PWM signal P2 is input to the pre-driver circuit 52.
[0095]
The pre-driver circuit 52 generates a switching signal S2 based on the input PWM signal P2, and outputs this switching signal to the gate terminals of the MOSFETs 78U to 78W and 80U to 80W.
[0096]
On the other hand, as shown in FIGS. 3 and 4, the CPU 62 includes a determination unit 94 that constitutes a control unit. The determination unit 94 is connected to the timer 68 and monitors the count number N of the timer 68. The timer 68 has a certain count number Ns as its upper limit, and beyond that, it overflows and cannot be counted. The determination unit 94 determines whether or not the timer 68 is in an abnormal state including an overflow state, and outputs a determination signal J based on the determination result to the output control unit 76.
[0097]
Based on the signal from the determination unit 94, the output control unit 76 outputs one of the input pulse signal P1 and PWM signal P2, and cancels the other.
[0098]
Further, as shown in FIG. 3, the output control unit 76 is connected to a signal correction unit 72 constituting a control means interposed between the control signal generation unit 74 and the output control unit 76, and FIG. As shown in FIG. 5, the signal is connected to a correction calculation unit 86 interposed between the input signal generation unit 84 and the comparison unit 88, and is output from the output control unit 76 (that is, the pulse signal P1 or the PWM signal P2). ) Is entered.
[0099]
The signal correction unit 72 cancels the pulse signal P1 when the pulse signal P1 is input. However, when the PWM signal P2 is input, the signal correction unit 72 appropriately converts the PWM signal P2 and generates the pulse generated by the control signal generation unit 74. Compared with the signal level of the signal P1, the duty ratio of the pulse signal P1 is increased or decreased based on the comparison result, and the increased or decreased pulse signal P1 is output to the output controller 76.
[0100]
On the other hand, when the PWM signal P2 is input in the correction calculation unit 86, the PWM signal P2 is canceled. However, when the pulse signal P1 is input, the pulse signal P1 is appropriately converted and generated by the input signal generation unit 84. Compared with the signal level of the input signal, the signal level of the input signal is increased or decreased based on the comparison result, and the input signal after the increase or decrease is input to the comparison unit 88.
[0101]
<Operation and effect of the present embodiment>
(Outline of basic operation)
Next, the operation and effect of the present embodiment will be described.
[0102]
In the motor control device 10, when the operation switch 58 is operated to turn on / off the air conditioner or switch the air volume, an operation signal having a predetermined voltage is input from the operation switch 58 to the speed command circuit 46.
[0103]
The operation signal input to the speed command circuit 46 is converted into a speed command signal V as a set value that can be compared by the CPU 62 of the speed control calculation unit 50 in the speed command circuit 46 and then passed through the power standby circuit 48. To the speed control calculation unit 50.
[0104]
Based on the speed command signal V input to the speed comparison unit 70 of the CPU 62 constituting the speed control calculation unit 50, the control signal generation unit 74 generates a pulse signal P 1 having a certain pulse width, and passes through the output control unit 76. And output to the pre-driver circuit 52.
[0105]
The pre-driver circuit 52 generates a pulsed switching signal S1 that can turn on / off each of the MOSFETs 78U to 78W and 80U to 80W based on the signal level and pulse width of the pulse signal P1 together with the booster circuit 56. The signal S1 is sent to the gate terminals of the MOSFETs 78U to 78W and 80U to 80W of the three-phase inverter 54.
[0106]
As described above, each of the MOSFETs 78U to 78W and 80U to 80W is in the OFF state when the received switching signal S1 is at the “LOW” level, and basically receives the current from the power source 60 from the drain terminal to the source terminal. If it is cut off and is at the “HIGH” level, it is in the ON state and current from the power supply 60 is allowed to flow from the drain terminal to the source terminal.
[0107]
Here, the switching signal S1 is generated based on the pulse signal P1. Therefore, any one of the MOSFETs 78U to 78W and any one of the MOSFETs 80U to 80W are alternately turned on, and as a result, the current rectified so that the energization waveform becomes a square wave as shown in FIG. It flows to 30W.
[0108]
In this way, a predetermined magnetic field is formed around the coils 30U to 30W, the magnet 24 is rotated by the interaction between the magnetic field formed by the coils 30U to 30W and the magnetic field formed by the magnet 24, and further integrated with the magnet 24. The shaft 20 rotates. As described above, since the shaft 20 is connected to the fan of the air conditioner on the outside of the housing 14, the fan rotates when the shaft 20 rotates, and thereby the air is blown from the air conditioner.
[0109]
On the other hand, when the shaft 20 rotates, the sensor magnet 42 rotates together. As described above, the sensor magnet 42 forms a multipolar magnet and forms a specific magnetic field around it. However, the rotation of the sensor magnet 42 causes the magnetic field of the sensor magnet 42 to be around the sensor magnet 42. Fluctuates.
[0110]
The fluctuation of the magnetic field around the sensor magnet 42 is a change in the strength of the magnetic lines of force at each rotational position around the sensor magnet 42. Magnetic field lines formed by the sensor magnet 42 are detected by the Hall IC elements 44U to 44W arranged around the sensor magnet 42. From each of the Hall IC elements 44U to 44W, position detection signals D1 to D3 having signal levels corresponding to the polarities of the sensor magnets 42 facing each other are output based on the detected strength of the magnetic field lines.
[0111]
In the speed comparison unit 70 of the CPU 62 constituting the speed control calculation unit 50, the actual rotational position C of the rotor 22 based on the position detection signals D1 to D3 output from the Hall IC elements 44U to 44W and the speed command signal V Is compared with the rotational position Cs of the rotor 22 on the setting based on the difference dC. The control signal generator 74 generates a pulse signal P1 based on the deviation dC.
On the other hand, among the Hall IC elements 44U to 44W, the position detection signal D1 from the Hall IC element 44U is also input to the period calculation unit 82. For example, when the detection signal when the Hall IC element 44U detects the N pole or the S pole of the sensor magnet 42 is input to the period calculation unit 82, the timer 68 is activated to start counting.
[0112]
When the period calculation unit 82 detects that the detection signal from the Hall IC element 44U corresponding to the number of poles of the sensor magnet 42 (total number of N poles and S poles) is switched from this state, the period calculation unit 82 The rotation period of the sensor magnet 42, that is, the rotation period T of the rotor 22 is calculated from the count number N of the timer 68 in the state, and the calculated rotation period T is further equally divided into, for example, an integer multiple of 6 A division value Tn is set.
[0113]
Next, the input signal generation unit 84 compares the actual rotation period T of the rotor 22 based on the division value Tn set by the period calculation unit 82 with the setting rotation period Ts based on the speed command signal V described above. Thus, a deviation dT is taken, and an input signal M having a predetermined waveform is generated based on the deviation dT. The input signal M generated by the input signal generation unit 84 is input to the comparison unit 88 via the correction calculation unit 86 and is compared with the triangular wave Tr as the reference wave generated by the triangular wave generation unit 90. Thereby, the PWM signal P2 is generated.
[0114]
Here, the input signal M is basically generated based on the divided value Tn. Moreover, the division value Tn is a value obtained by equally dividing the rotation period T into an integral multiple of 6. Of these divided values Tn, divided values T1, T2, T3, T4, T5, and T6 obtained by equally dividing the rotation period T into six basically have signal levels of the position detection signals D1, S2, and S3. Corresponds to switching. Therefore, by setting the energization start and energization stop timings for the coils 30U to 30W based on the division values T1 to T6, energization of the coils 30U to 30W is started at the same timing as the pulse signal P1, Or you can stop.
[0115]
However, since the division value Tn is a value obtained by dividing the rotation period T into an integral multiple of 6, for example, the division values T1 to T6 obtained by equally dividing the rotation period T into six parts are further equally divided. . The input signal generation unit 84 sets the signal level of the input signal M for each divided value Tn obtained by further equally dividing the divided values T1 to T6.
[0116]
In this manner, the output control unit 76 outputs the PWM signal P2 generated based on the input signal M in which the signal level is set for each of the division values Tn including the division values T1 to T6 and the division value in the middle of each. Then, the PWM signal P2 is input to the pre-driver circuit 52. The pre-driver circuit 52 generates a pulsed switching signal S2 that can turn on / off each of the MOSFETs 78U to 78W and 80U to 80W based on the signal level and pulse width of the PWM signal P2 together with the booster circuit 56. The signal S2 is sent to the gate terminals of the MOSFETs 78U to 78W and 80U to 80W of the three-phase inverter 54.
[0117]
Here, since the pulse signal P1 is simply a signal based only on the rotational position of the rotor 22, basically only the timing of starting and stopping energization of the coils 30U to 30W can be controlled. For this reason, when the coils 30U to 30W are energized by the switching signal based on the pulse signal P1, the energization waveform is a square wave as described above.
[0118]
On the other hand, the PWM signal P2 is generated based on the input signal M in which the signal level is set for each of the divided values Tn including the divided values T1 to T6 and the divided values in the middle of each as described above. For this reason, the control which further subdivided the energization timing of each coil 30U-30W is performed. As a result, as shown in FIGS. 7 and 8, in the present embodiment, the energization waveforms of the coils 30U to 30W based on the PWM signal P2 are not simple square waves, but at the time of energization start and energization stop. In FIG. 4, the waveform becomes an arbitrary waveform such as a symmetrical trapezoidal wave or sine wave whose energization level gradually increases or decreases (in this embodiment, a symmetrical trapezoidal wave). As a result, torque ripple is reduced and the rotor 22 can be rotated more smoothly than in the case where the energization waveform is a square wave based on the pulse signal P1 as the first control signal.
[0119]
On the other hand, as described above, the PWM signal P <b> 2 generated by the comparison unit 88 is input to the output control unit 76. Here, the output control unit 76 receives the determination signal J from the determination unit 94.
[0120]
The determination unit 94 receives a count (count) signal N from the timer 68. As described above, the timer 68 is basically configured so as not to be able to count (count) exceeding a certain upper limit value Ns. Therefore, it is assumed that the rotation period T of the rotor 22 exceeds the upper limit value Ns of the timer 68. In this case (that is, when the rotor 22 does not rotate once even when the upper limit value Ns of the timer 68 is exceeded), the PWM signal P2 is canceled by the output control unit 76 based on the determination signal J from the determination unit 94, and the pulse The signal P1 is input to the predriver circuit 52.
[0121]
On the other hand, when the rotation period T of the rotor 22 is less than or equal to the upper limit value Ns of the timer 68 (that is, when the count number N at the timer 68 in a state where the rotor 22 has made one rotation does not exceed the upper limit value Ns). Based on the determination signal J from the determination unit 94, the output control unit 76 cancels the pulse signal P1, and the PWM signal P2 is input to the pre-driver circuit 52.
[0122]
As described above, in this embodiment, two types of control signals, the pulse signal P1 and the PWM signal P2, are generated. The control signal input to the pre-driver circuit 52 is either the pulse signal P1 or the PWM signal P2. One of the control signals. For this reason, two types of control signals having different waveforms (that is, the pulse signal P1 and the PWM signal P2) are not mixedly output.
[0123]
In addition, as described above, the energization waveform in the switching signal S2 based on the PWM signal P2 is an arbitrary waveform such as a trapezoidal wave. Basically, energizing each of the coils 30U to 30W based on the PWM signal P2 The torque ripple is small and the rotor 22 can be smoothly rotated, which is preferable. However, in the case where the rotor 22 does not rotate once even if the count number N in the timer 68 which is a reference for calculating the rotation period T exceeds the upper limit value Ns, the count number N in the timer 68 An accurate rotation period T cannot be calculated. However, in the present embodiment, when the accurate rotation period T cannot be calculated from the count number N of the timer 68 in this way, the PWM signal P2 is canceled and each of the coils 30U to 30W based on the pulse signal P1. Can be energized at an appropriate energization timing.
[0124]
By the way, in this embodiment, as described above, the control signals (that is, the pulse signal P1 and the PWM signal P2) output from the output control unit 76 are appropriately switched according to the count number N in the timer 68.
[0125]
Here, in the present embodiment, when the control signal output from the output control unit 76 is switched from the pulse signal P1 to the PWM signal P2, the signal level of the input signal M output from the input signal generation unit 84 is corrected. In the calculation part 86, it correct | amends according to the duty ratio of the pulse signal P1 output from the output control part 76 just before that. For this reason, the duty ratio of the PWM signal P2 based on the corrected input signal M immediately after switching is corrected, and as a result, the duty ratio of the switching signal S2 is corrected.
[0126]
Thereby, the peak value of the signal level of the energization waveform in each of the coils 30U to 30W becomes smaller than that in the case where the correction calculation unit 86 does not correct (see FIG. 9). Therefore, compared to the case where the above correction is not performed, the output when the coils 30U to 30W are energized with the switching signal S2 based on the PWM signal P2, and the pulse output from the output control unit 76 immediately before that. The deviation from the output when energized with a square wave energization waveform by the switching signal S1 generated based on the signal P1 is small or no deviation occurs. Thereby, chattering, torque fluctuation, and the like due to the output difference are reduced or prevented.
[0127]
On the other hand, when the control signal output from the output control unit 76 is switched from the PWM signal P2 to the pulse signal P1, the duty ratio of the pulse signal P1 output from the control signal generation unit 74 is set immediately before the signal correction unit 72. The PWM signal P2 output from the output control unit 76 is corrected according to the duty ratio. Therefore, immediately after the switching, the duty ratio of the switching signal S1 is corrected, whereby the peak value of the signal level of the energization waveform in each of the coils 30U to 30W becomes larger than when the signal correction unit 72 does not correct (FIG. 10).
[0128]
Therefore, compared to the case where the above correction is not performed, the output when the coils 30U to 30W are energized with the switching signal S1 based on the pulse signal P1, and the PWM output from the output control unit 76 immediately before that. The deviation from the output when energized with a trapezoidal wave energization waveform by the switching signal S2 generated based on the signal P2 is reduced or eliminated. Thereby, chattering, torque fluctuation, and the like due to the output difference are reduced or prevented.
[0129]
As described above, in the present embodiment, the control signal (that is, the pulse signal P1 or the PWM signal P2) to be output appropriately is switched according to the count number N in the timer 68, but the output waveforms before and after the switching ( Since the chattering and torque fluctuation are prevented by correcting the difference in the energization waveform), the generation of abnormal noise or the like during the operation of the brushless motor 12 can be effectively reduced or prevented, and the rotor 22 is smoothly rotated. be able to.
[0130]
<Second Embodiment>
Next, a second embodiment of the present invention will be described. In the description of the second embodiment, the same reference numerals as those in the first embodiment are given to the portions that are substantially and functionally the same as those in the first embodiment. The description is omitted.
[0131]
As shown in FIGS. 11 and 12, the CPU 62 of the motor control device 110 according to the present embodiment is different from the CPU 62 of the motor control device 10 according to the first embodiment. The signal correction unit 72 and the correction calculation unit 86 are not provided, but instead, the input signal generation unit 112 and the signal correction unit 114 and the correction calculation unit 116 that respectively constitute control means are provided.
[0132]
The input signal generation unit 112 basically has the main function of generating the input signal M similarly to the input signal generation unit 84. However, the input signal M generated by the input signal generator 112 has a different waveform from the input signal M generated by the input signal generator 84.
[0133]
For this reason, the PWM signal P2 based on the input signal M generated by the input signal generation unit 112 has a duty ratio different from the PWM signal P2 based on the input signal M generated by the input signal generation unit 84. Accordingly, the PWM signal P2 is generated based on the input signal M generated by the input signal generation unit 112, and further, the switching signal S2 is generated based on the PWM signal P2 to energize the coils 30U to 30W. Unlike the first embodiment, the energization waveform is a left-right asymmetric trapezoidal wave.
[0134]
On the other hand, the signal correction unit 114 and the correction calculation unit 116 function to shift the phase of the pulse signal P1 or the input signal M in addition to the same functions as the signal correction unit 72 and the correction calculation unit 86 in the first embodiment. Have
[0135]
That is, the signal correction unit 114 corrects the duty ratio of the pulse signal P1 output from the control signal generation unit 74 according to the duty ratio of the PWM signal P2 output from the output control unit 76, and is shown in FIG. As described above, similarly to the first embodiment, the output level of the final energization waveform is corrected, and the phase (energization timing) is corrected by dT.
On the other hand, the correction calculation unit 116 corrects both the signal level and the generation timing of the input signal M output from the input signal generation unit 112 according to the duty ratio of the pulse signal P1 output from the output control unit 76. Thereby, the duty ratio of the PWM signal 2 generated based on the input signal M and the triangular wave Tr is corrected. As a result, as shown in FIG. 14, the output level of the final energization waveform is corrected as in the first embodiment, and the phase (energization timing) is further corrected by dT.
[0136]
As described above, in this embodiment, the signal correction unit 114 and the correction calculation unit 116 have the same functions as the signal correction unit 72 and the correction calculation unit 86 in the first embodiment. The same effect as the first embodiment can be obtained, and the same effect can be obtained.
[0137]
By the way, in the present embodiment, as described above, since the final energization waveform based on the PWM signal P2 is a left-right asymmetric trapezoidal wave, the time center between energization start and energization stop, The center of the effective current area shifts.
[0138]
Here, in the present embodiment, as described above, when the control signals output from the output control unit 76 (that is, the pulse signal P1 and the PWM signal P2) are switched, the control signal immediately before the switching (that is, the pulse signal). The duty ratio of the control signal (that is, the other of the pulse signal P1 and the PWM signal P2) output from the output control unit 76 immediately after switching is corrected based on one of the P1 and the PWM signal P2, and the final The phase (energization timing) of the energization waveform is corrected by dT. For this reason, torque fluctuations immediately before and after switching of the control signal due to phase shift are effectively suppressed or prevented. Thereby, generation | occurrence | production of the noise accompanying torque fluctuation, etc. can be reduced or prevented, and rotation of the rotor 22 can be stabilized.
[0139]
In each of the above-described embodiments, the control signal output from the output control unit 76 has a condition that the pulse signal P1 is switched to the PWM signal P2, and the rotation period of the rotor 22 is the upper limit value Ns of the count number in the timer 68. The condition was not exceeded. Here, when this condition is simply cleared, the control signal output from the output control unit 76 may be switched from the pulse signal P1 to the PWM signal P2. However, for example, switching of the control signal is suspended for a plurality of periods. In addition, the control signal output from the output control unit 76 may be switched from the pulse signal P1 to the PWM signal P2 only when the above condition is continuously cleared during that time.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an outline of a configuration of a brushless motor (motor control device) according to a first embodiment of the present invention.
FIG. 2 is a diagram schematically showing the configuration of rectifying means of the brushless motor (motor control device) according to the first embodiment of the present invention.
FIG. 3 is a block diagram illustrating a schematic configuration of a CPU with a focus on a function of generating a first control signal (pulse signal).
FIG. 4 is a block diagram showing an outline of a configuration of a CPU focusing on a function of generating a second control signal (PWM signal).
FIG. 5 is a schematic front sectional view of the brushless motor according to the first embodiment of the present invention.
FIG. 6 is a schematic time chart showing a relationship between a position detection signal from a rotational position detection unit and a waveform of energization to a coil based on a first control signal (pulse signal).
FIG. 7 is a schematic time chart showing the relationship between a cycle detection signal from a cycle detection means and a current-carrying waveform to a coil based on a second control signal (PWM signal).
8 is an enlarged time chart of a part of FIG.
FIG. 9 is a time chart showing a relationship between an energization waveform based on a first control signal, an energization waveform based on a second control signal before correction, and an energization waveform based on a second control signal after correction.
FIG. 10 is a time chart showing a relationship between an energization waveform based on a second control signal, an energization waveform based on a first control signal before correction, and an energization waveform based on a first control signal after correction.
FIG. 11 is a block diagram corresponding to FIG. 3 and schematically showing a configuration of a brushless motor (motor control device) according to a second embodiment of the present invention.
FIG. 12 is a block diagram corresponding to FIG. 4 and schematically showing a configuration of a brushless motor (motor control device) according to a second embodiment of the present invention.
FIG. 13 is a time chart showing a relationship between an energization waveform based on a first control signal, an energization waveform based on a second control signal before correction, and an energization waveform based on a second control signal after correction.
FIG. 14 is a time chart showing a relationship between an energization waveform based on a second control signal, an energization waveform based on a first control signal before correction, and an energization waveform based on a first control signal after correction.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Motor control apparatus, 12 ... Brushless motor (motor), 22 ... Rotor (rotor), 24 ... Magnet (permanent magnet), 28 ... Stator (stator), 30U, 30V, 30W ... coil, 40 ... rotation detection device (rotation position detection means), 44U ... Hall IC element (rotation position detection means, cycle detection means), 54 ... three-phase inverter (rectification means) , 68... Timer (timer means), 72... Signal correction section (control means), 74... Control signal generation section (control signal generation means), 76. , 86... Correction calculation section (control means), 92... PWM signal generation section (control signal generation means), 94... Judgment section (control means), 110. .Signal correction unit (control means), 116. And correction arithmetic unit (control means)

Claims (8)

A stator having a multi-phase coil that forms a predetermined magnetic field around the energized state;
A rotor that has a permanent magnet and rotates by a rotational force generated by the interaction between the magnetic field formed by the coils of the plurality of phases and the magnetic field formed by the permanent magnet;
Rotation position detection means for detecting a rotation position of the rotor and outputting a position detection signal based on the detected rotation position;
A period detecting means for detecting a period of the rotor and outputting a period detection signal based on the detected period;
Based on the first control signal having a predetermined waveform based on the position detection signal and the waveform different from the first control signal based on the period detection signal, the energization waveform when the coil is finally energized is not subject to right and left Control signal generating means capable of generating both of the second control signals having a current-carrying waveform of
Switch with, what Re or other control signals before or SL one of the control signals et when certain conditions are met and outputs either one of the control signal of the first control signal and said second control signal Control means for outputting,
Rectifying means for energizing or de-energizing each of the coils of the plurality of phases at a timing based on the first control signal or the second control signal output from the control means;
In addition, when switching the control signal output by the control means, the control means, the energization waveform when the coil is energized based on any one of the output control signals, Either one of the other control signals based on one of the control signals to reduce or eliminate the deviation from the energization waveform when the coil is energized based on the other control signal And a deviation between the time center from the start of energization to the stop of energization when the coil is energized based on one of the other control signals and the center of the current effective area of the energization waveform. Correcting one of the other control signals based on the one of the control signals output immediately before the switching to be corrected;
A brushless motor characterized by that . The rotational position including a plurality of magnetic sensors that detect magnetic poles of the permanent magnets that are arranged around the rotor and that constitute the rotor, or other permanent magnets provided integrally with the rotor. While configuring the detection means,
The period detection means including a timer means for counting from a predetermined rotation position until the rotor makes one rotation based on a detection signal output from any one of the plurality of magnetic sensors. And the period detection signal as a count signal based on the count value of the timer means,
The brushless motor according to claim 1. The timer means has an upper limit value for counting, and a state where the count value by the timer means is within the upper limit value is set as the specific condition,
Switching the control signal output by the control means from the first control signal to the second control signal when the specific condition is satisfied;
The brushless motor according to claim 2. Based on the count signal, the control means determines whether or not the timer means is operating normally, and the state determined by the control means that the timer means is operating normally is the specific condition. As well as
Switching the control signal output by the control means from the first control signal to the second control signal when the specific condition is satisfied;
The brushless motor according to claim 2 or 3, wherein the brushless motor is provided. A square in which the energization waveform of the current flowing through each of the plurality of phase coils based on the first control signal is energized or deenergized based on the magnetic pole positions of the permanent magnets detected by the plurality of magnetic sensors. Wave and
The energization waveform based on the second control signal is a trapezoidal wave with different energization levels depending on the phase of the rotor.
The brushless motor according to any one of claims 1 to 4, wherein the brushless motor is provided. An input signal based on the period detection signal is compared with a reference wave having a predetermined waveform, and the control signal generating means generates the second control signal having a pulse width different according to the level of the input signal, and the specific signal When the condition is satisfied, the control signal output by the control means is switched from the first control signal to the second control signal, and the duty ratio of the second control signal is changed based on the first control signal at the time of the switching. to correct,
The brushless motor according to any one of claims 1 to 5, wherein the brushless motor is provided. The control means corrects the phase of the other control signal based on the one control signal output immediately before the switching;
The brushless motor according to any one of claims 1 to 6, wherein the brushless motor is provided. A motor control device for controlling a motor in which a rotor rotates by a rotational force generated by an interaction between a magnetic field formed by current flowing in a plurality of coils and a magnetic field formed by a permanent magnet,
Rotation position detection means for detecting a rotation position of the rotor and outputting a position detection signal based on the detected rotation position;
A period detecting means for detecting a period of the rotor and outputting a period detection signal based on the detected period;
Based on the first control signal having a predetermined waveform based on the position detection signal and the waveform different from the first control signal based on the period detection signal, the energization waveform when the coil is finally energized is not subject to right and left Control signal generating means capable of generating both of the second control signals having a current-carrying waveform of
Switch with, what Re or other control signals before or SL one of the control signals et when certain conditions are met and outputs either one of the control signal of the first control signal and said second control signal Control means for outputting,
Rectifying means for energizing or de-energizing each of the coils of the plurality of phases at a timing based on the first control signal or the second control signal output from the control means;
In addition, when switching the control signal output by the control means, the control means, the energization waveform when the coil is energized based on any one of the output control signals, Either one of the other control signals based on one of the control signals to reduce or eliminate the deviation from the energization waveform when the coil is energized based on the other control signal And a deviation between the time center from the start of energization to the stop of energization when the coil is energized based on one of the other control signals and the center of the current effective area of the energization waveform. Correcting one of the other control signals based on the one of the control signals output immediately before the switching to be corrected;
The motor control apparatus characterized by the above-mentioned.

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