JPH11275881A - Control method for brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the convergence speed and convergence accuracy of pulsation by offsetting the load pulsation. SOLUTION: The DC voltage obtained with an AC/DC converter 2 is switched with an inverter part 3 and is applied to a brushless motor 4 for rotating the brushless motor 4. A control circuit 10 controls an inverter part 3, so as to switch the current application of the brushless motor 4, based on the detected position of the rotor obtained with a position detecting circuit 5 on one hand, and divides one rotation into a plurality of divisions with an interval-between-position-detections computing part 10 and also clocks the time of each division, and generates corrective voltage separately for each division with a torque pattern operating part 10c, based on this clocked time. At the generation of this corrective voltage, it computes estimated coefficient S with a coefficient S generating part 10c, based on the time of each division, and generates the corrective voltage in order by this estimated coefficient S. This adds generated corrective voltage to the PWM signal from a PWM signal generator 10 with an adder 10e, and this outputs the drive signal of an inverter part 3 with a current application switch controller 10f by the PWM signal where this corrective voltage is added, and performs the offsetting of load pulsation by correcting the voltage pattern to be applied to the brushless motor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for controlling a sensorless DC brushless motor (hereinafter, referred to as a brushless motor) used for a motor such as an air conditioner (compressor). The present invention relates to a brushless motor control method that enables rotation control.

[0002]

2. Description of the Related Art In a method of controlling a brushless motor, for example, an induced voltage waveform generated in a non-energized phase of a three-phase four-pole brushless motor is compared with a reference value, and a zero-cross point (so-called rotor position) of the comparison result is compared. The energization pattern of the armature winding is switched based on the (detection point). At this time, if the energization is switched to the next phase with a slight delay from the position detection point, the rotation can be efficiently maintained.
The slight delay phase takes a value of 30 degrees or less in electrical angle. Therefore, in the rotation control by the microcomputer described later, a time corresponding to a value of an electrical angle of 30 degrees or less is calculated based on the past position detection interval or the average of a plurality of past position detection intervals, and the position detection point is calculated. The energization is switched when the calculated time elapses from the time.

For this reason, for example, a control device shown in FIG. 6 is required. This control device converts an AC power supply 1 into a predetermined DC power supply by an AC / DC conversion unit 2 and converts the DC power supply into switching elements Ua, Va, Wa, X,
Brushless motor (DCM) with Y and Z switching
4 is supplied to the armature winding.

The position detection circuit 5 compares an induced voltage waveform (induced voltage waveform generated in a non-energized phase) included in the terminal voltages of the armature windings U, V, and W of the brushless motor 4 with a reference value. To detect a half point of the induced voltage waveform.
A position detection signal including the / 2 point is output to a control circuit (mainly composed of a microcomputer) 6.

The control circuit 6 detects the induced voltage 1 by the edge (rising edge, falling edge) of the input position detection signal.
/ 2 points (rotor position detection points) are detected, and a position detection interval is calculated based on the current position detection time and the previous position detection time. Further, for example, a time corresponding to a value equal to or less than 30 degrees of the electrical angle is calculated from the past position detection intervals, and the calculated time is added to the current position detection time to estimate the next energization switching time. When the estimated time comes, a predetermined drive signal is output to the inverter unit 3 via the drive circuit 7 to switch the energization.

Thus, the switching elements Ua, Va, Wa, X, Y and Z of the inverter section 3 are switched,
That is, the energization of the armature windings U, V, W is appropriately switched, so that efficient rotation control can be performed.

[0007]

However, in the brushless motor control method, when the load fluctuates, the speed of the brushless motor 4 fluctuates due to the fluctuation, and as a result, mechanical vibration occurs in the brushless motor 4. In addition, noise is not generated, and smooth rotation is not performed. That is, for example, in a compressor of an air conditioner or the like, there is a pulsation that is a fluctuation (that is, a regular fluctuation) of the rotation synchronization due to the compression process, and the optimal energization switching timing also changes with the load pulsation. .

Further, if noise occurs at the time of energization switching, erroneous position detection may occur due to this noise. Therefore, the position detection signal is masked at least for a certain time after the energization switching (FIGS. 7B and 7B). d)). As shown in FIG. 7A, with normal rotation, a regular position detection point can be obtained without the mask touching the position detection point. However, as shown in FIG. 7 (c), the induced voltage changes due to the above-described load pulsation, and the mask hides the normal position detection point, thereby causing an erroneous position detection and causing the worst step-out and stop. Will be invited.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to stably cancel pulsation and perform stable rotation control even under a load condition in which pulsation exists.
It is another object of the present invention to provide a brushless motor control method capable of suppressing vibration and noise.

[0010]

In order to achieve the above object, the present invention detects a position of a rotor of a brushless motor, and based on the detected position, energizes an armature winding of the brushless motor. In the method of controlling a brushless motor, one rotation of the brushless motor is divided into a plurality of sections, the time of each section is measured, and an average value (section time average value) for a plurality of rotations for each section is provided. ) To calculate the average value (average section time) of these section time average values, and calculate the time difference value between the section time average value and the average section time, respectively, based on the time difference value. A correction voltage of a torque pattern for correcting an applied voltage of the brushless motor, and adding the corrected voltage to an applied voltage of the brushless motor. That.

The present invention relates to a brushless motor control method for detecting the position of a rotor of a brushless motor and switching energization of an armature winding of the brushless motor based on the detected position. The rotation is divided into a plurality of sections, the time of each section is measured, the average value (section time average value) is calculated for each of the plurality of rotations for each section, and the average value of these section time average values ( Average section time), calculate the time difference between the section time average and the average section time, and correct the applied voltage of the brushless motor by multiplying the time difference by a predetermined coefficient (estimated coefficient). It is characterized in that a correction voltage of the torque pattern to be generated is generated and can be sequentially updated.

In this case, the predetermined coefficient is obtained by multiplying a reciprocal of a product of a maximum value of the section time average value, an average section time and the number of divided sections by a constant of an induced voltage generated in a non-energized phase of the brushless motor. It is preferable that the value be smaller than the obtained value.

The predetermined coefficient is represented by a function using the rotation speed of the brushless motor as a variable. The higher the rotation speed is, the larger the predetermined coefficient is, and the lower the rotation speed is, the higher the predetermined coefficient is. It is good to make a coefficient small.

The predetermined coefficient is a value set in advance for each of a plurality of zones obtained by dividing the rotation control range of the brushless motor. The higher the number of rotations is, the larger the predetermined coefficient is. The lower the area, the smaller the predetermined coefficient may be.

It is preferable that the pulsation of the brushless motor is detected by calculating an average value of the time difference values for each section, and the predetermined coefficient is varied in accordance with the evaluation amount of the detected pulsation. .

The mean value of the time difference value for each section is calculated to detect the pulsation of the brushless motor, and the evaluation value of the detected pulsation is divided into a plurality of zones, and the predetermined coefficient is determined for each zone. The predetermined coefficient may be increased as the evaluation amount increases, and the predetermined coefficient may be decreased as the evaluation amount decreases.

Further, it is preferable that at the start of generation of the correction voltage, the predetermined coefficient be set to a large value, and the generation of the correction voltage be made to decrease the predetermined coefficient.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to FIGS. FIG.
6, the same parts as those in FIG.

In the brushless motor control method of the present invention, as shown in FIG. 2, one rotation is divided into L and an average value (section time average value) PPl (1 to 1) for a plurality of rotations for each section.
L) and their average value (average section time)
PPa and their time difference ΔPl (value = PPl−P
Pa), the pulsation during one rotation is statistically extracted, and a correction voltage (torque pattern) of the applied voltage of the brushless motor is generated in accordance with the time difference value ΔPl. Stable rotation control is possible by canceling the pulsation of the motor.

The present invention will be described in principle with reference to a time chart shown in FIG. 2. First, one rotation is divided into a plurality of parts (divided into l (1 to L) sections) by a position detection signal.
Further, the time Pl (P1 to PL) of those sections is detected. It should be noted that L may be arbitrarily set, but a three-phase four-pole motor can easily be divided into 12 parts. While detecting and storing the section times P1 to PL of each section for M rotations, the section times P1 to P until the Mth rotation are applied by applying the following equation 1.
L is added for each section, and the value obtained by adding these (P11
+... + P1M),..., (PL1 +... + PLM) divided by the number of revolutions M to obtain an L average value (section time average value) PP1 to P
Calculate PL.

[0021]

(Equation 1)

Furthermore, the section time average value PP of each section
l (PP1 to PPL) is applied to the following equation 2 and added.
Further, the average section time PPa is calculated by dividing the value (PP1 +... + PPL) obtained by the addition by the number of divisions L per rotation.

[0023]

(Equation 2)

Further, the difference between each section time average value PP1 to PPL and the average section time PPa is calculated by applying the following equation 3, and the calculated values (PP1-PPa,...)
PPL-PPa) is defined as a difference value ΔPl (ΔPl to ΔPL).

[0025]

(Equation 3)

The time difference value ΔPl can be regarded as a change in each of the sections 1 to L, that is, a vector quantity that determines the correction amount and the direction (positive or negative direction) of the applied voltage of the brushless motor 4.

That is, white noise can be removed by the above-mentioned averaging process, and only regular pulsating components (pulsating components of the compressor load) can be extracted. Then, the correction voltage ΔV of the torque pattern is estimated based on the time difference value ΔPl. For example, Equation 4 below is applied to the estimation.

[0028]

(Equation 4)

In the above formula 4, n (an integer of 0 or more)
Is an estimation number, and S is an estimation coefficient. When the number of estimations is zero (when estimation is not performed at the beginning)
ΔV0 is set to zero, and the correction voltage ΔV is estimated every predetermined rotation (for example, one rotation) after the Mth rotation.

When one rotation is divided into 12 parts, the estimation coefficient S may be defined by the following equation (5).

[0031]

(Equation 5)

Here, in the inequality expression of the estimation coefficient S,
k is a constant proportional to the induced voltage, and PPlmax is the maximum value of each section time average value PP1 (PP1 to PPL). Then, when the correction voltage ΔV is generated, the estimation coefficient S is determined to be a value smaller than the right side of Expression 5 above.

The reason why the equation for the estimation coefficient S is unequal is that if the equation is used, a desired correction voltage can be calculated by one operation, but the following problem arises. That is, since the rotation fluctuation includes not only the fluctuation synchronized with the rotation but also the non-synchronization fluctuation, the corrected applied voltage does not always act as the negative feedback. Excitation (self-oscillation) may occur. In consideration of such a thing, it is desirable to gradually reduce the estimation coefficient S, that is, to gradually converge and absorb pulsations gradually.

That is, as is clear from Equation 5, when the right side of the equation proceeds to a region where the rotational speed is high (a region where pulsation is small due to the moment of inertia), the induced voltage constant k is large and the average section time PPa is small. Therefore, when the estimation coefficient S increases, and the engine speed advances to a low rotational speed region (a region where pulsation is large due to the moment of inertia),
Since the induced voltage constant k is small and the average section time PPa is a large value, the estimation coefficient S is small. Thereby, the torque pattern of the correction voltage ΔV is sequentially updated.

It is also possible to cancel the estimation of the correction voltage ΔV before the pulsation is canceled out, that is, before the asynchronous fluctuation affects the time difference value ΔP1 shown in the equation (3).

Further, the estimation coefficient S has a trade-off relationship between convergence speed and convergence accuracy. That is,
If the convergence accuracy is to be increased, the convergence speed will be slow, and if the convergence speed is to be increased, the convergence accuracy will be poor. Therefore, instead of Equation 4 for calculating the estimation coefficient S, a function S (x) using the rotation speed as a variable as shown in Equation 6 below.
Should be introduced.

[0037]

(Equation 6)

That is, the pulsation is small due to the moment of inertia in a region where the rotation speed is high, and the pulsation is large in a region where the rotation speed is low. Therefore, if the estimation coefficient S is changed according to the rotation speed (by changing x), it is possible to increase the convergence speed and improve the convergence accuracy.

In this case, the estimation coefficient may be changed for each rotation speed. However, the estimation coefficient is determined corresponding to each preset rotation speed (rotation speed zone), and the determined estimation coefficient is stored in an internal memory. (ROM) (see FIG. 3), and read out from the memory for each rotation speed zone and apply to the above-mentioned equation (6). For example, in a region where the rotational speed is high, the pulsation is suppressed by the moment of inertia. Therefore, the estimation coefficient S (x) is set to a large value with emphasis on high-speed convergence. That is,
If the estimation coefficient S (x) is increased, as is clear from Equation 4, the correction voltage of the applied voltage increases, that is, the pulsation cancels faster.

Since the pulsation is remarkable in the region where the rotational speed is low because the moment of inertia is small, the estimation coefficient S (x) is set to a small value with emphasis on the convergence accuracy.
That is, if the estimation coefficient S (x) is reduced, as is clear from the above-mentioned Expression 4, the correction voltage of the applied voltage is small (the amount of cancellation of the pulsation is small). The reason is that the pulsation can be accurately canceled without any problem.

In order to execute the control method of the present invention by applying the above-described formula, the control device shown in FIG. 1 includes a control circuit 10 mainly composed of a microcomputer for executing at least the above-described processing.

The control circuit 10 measures a pulse interval (a so-called position detection interval) using an edge (rising edge, falling edge) of the position detection signal (pulse signal) from the position detection circuit 5 using an internal timer or the like, and determines the position. A position detection interval calculation unit 10a that measures the time of the detection interval, a PWM signal generation unit 10b that generates a PWM signal for performing constant rotation control based on the time of the position detection interval, and an operation illustrated in FIG. And a coefficient S generating unit 1 that calculates and determines an estimation coefficient used in the calculation.
2d, an adder 10e that adds a torque pattern of a correction voltage to the PWM signal, and an energization switching controller 10f that generates a drive signal for driving the inverter 3 based on the corrected PWM signal. . The control circuit 10
Also has the function of the control circuit 6 shown in FIG.

Next, the operation of the control device having the above configuration will be described. First, the control circuit 10 counts the time of the position detection interval based on the position detection signal from the position detection circuit 5, while detecting the position detection time. The interval time (section time) is at least m
Remember the rotation. If there is a load pulsation during the rotation of the brushless motor 4, the position detection interval time fluctuates. Based on the position interval time, the above-mentioned formulas 1 to 3 are used.
, The time difference value ΔPl (ΔP1 to ΔPL) of each section is calculated. Since the calculated time difference value ΔPl is a basic vector amount that determines the magnitude and direction (positive or negative direction) of the correction voltage of the applied voltage, the time difference value ΔPl is applied to the above equation 4 to correct each section. A torque pattern of the voltage ΔV is generated and added to the PWM signal. Thus, the applied voltage of the brushless motor 4 changes by the correction voltage ΔV, that is, the correction voltage ΔV acts to cancel the pulsation.

At this time, as described above, when the estimation coefficient S shown in Expression 5 is used, the estimation coefficient S is the maximum value PPlm of the average value PP1 (PP1 to PPL) of each section time.
This value is smaller than the value obtained by multiplying the reciprocal of the product of the reciprocal of ax, the average section time PPa, and the number of divisions L per rotation by the induced voltage constant k. Then, after the Mth rotation, the correction voltage ΔV
On the other hand, since the estimation coefficient S is sequentially reduced, the correction voltage ΔV is sequentially updated. With the torque pattern of the correction voltage ΔV estimated in this way, the applied voltage can be increased or decreased by the correction voltage ΔV in each section of one rotation of the brushless motor 4, and the applied voltage is corrected by sequentially updating the correction voltage ΔV. can do.

Therefore, in the case of a pulsation load of a compressor or the like, pulsation characteristics may be statistically exhibited. In such a case, the pulsation can be effectively canceled, that is, the rotation speed synchronization. The load pulsation generated in the above is canceled. The offset of the load pulsation also prevents the mask from hiding the position detection point, thereby eliminating erroneous position detection.

When the value of the estimation coefficient S (x) is stored in an internal memory for each rotation speed zone (or rotation speed), the estimation coefficient S (x) corresponding to the current rotation speed of the brushless motor 4 is obtained. Is read out by the coefficient S generating unit 10d and applied to the equation (6). Then, when the rotational speed is in a high region, that is, when the moment of inertia is large, the value of the estimation function S (x) is large, so that the estimation of the torque pattern is coarse, and the convergence of the pulsation is accelerated (pulsation). Can be shortened). Further, when the rotational speed is in a low range, that is, when the moment of inertia is small, the value of the estimation function S (x) is small, so that the estimation of the torque pattern becomes finer, and the convergence of the resulting pulsation is improved ( Appropriate cancellation of remarkable pulsation can be achieved.

FIG. 4 is a schematic block diagram for explaining another embodiment of the present invention. In the figure, the same parts as those in FIG.

The control device to which the brushless motor control method is applied includes a pulsation evaluation amount u for detecting a convergence degree (evaluation amount) of the pulsation using the time of the position detection interval calculated by the position detection interval calculation section 10a. A calculating unit 11a and a coefficient S that uses the pulsation evaluation amount u as a determination index of the estimation coefficient S (x)
And a control circuit 11 having a generation unit 11b. The control circuit 11 includes a position detection interval calculation unit 10a and a PWM signal generation unit 10 like the control circuit 10 shown in FIG.
b, a torque pattern calculation unit 10c, an addition unit 10e, and an energization switching unit 10f.

The pulsation evaluation amount u is calculated by the following equation (7).

[0050]

(Equation 7)

Describing Equation 7, the time difference value ΔPl (PP1-PPa,..., PPL-PP)
A value obtained by dividing the average value of the sum of absolute values of a) by the number of divisions L is defined as a pulsation evaluation amount u.

Further, as shown in FIG. 5, an estimation coefficient S is determined in advance corresponding to the pulsation evaluation amount u and stored in an internal memory. In this case, the pulsation evaluation amount u is divided into zones, a large estimation coefficient S is stored in a zone with a large pulsation evaluation amount u, and a small estimation coefficient S is stored in a zone with a small pulsation evaluation amount u. Good to put. Then, when the pulsation is large, a large value of the estimation coefficient S is generated by the estimation coefficient S generating unit 11b, so that the correction voltage Δ
Although estimation of V becomes coarse, convergence of pulsation can be accelerated.
That is, when the estimation of the correction voltage ΔV progresses, that is, when the pulsation becomes small, the estimation coefficient S having a small value is generated by the estimation coefficient S generating unit 11b, and the estimation of the torque pattern becomes finer. High convergence accuracy can be achieved.

[0053]

As described above, according to the first aspect of the brushless motor control method, one revolution of the brushless motor is divided into a plurality of sections, and the time of each section is measured. Calculate the average value (section time average value) for multiple rotations for each section,
While calculating the average value (average section time) of these section time average values, the time difference value between the section time average value and the average section time is calculated, and the brushless motor of the brushless motor is calculated based on the time difference value. Since the correction voltage of the torque pattern for correcting the applied voltage is obtained and the corrected voltage is added to the applied voltage of the brushless motor, pulsation during one rotation, for example, pulsation of the compressor load can be canceled. Moreover, since white noise and the like are removed by the averaging process, the pulsation can be canceled and stable rotation control can be performed, so that motor vibration and noise can be suppressed. Has the effect of being useful.

According to the second aspect of the present invention, one rotation of the brushless motor is divided into a plurality of sections, the time of each section is measured, and the average value (section time) for each of the plurality of rotations is calculated for each section. Average value) and the average value (average section time) of these section time average values, while calculating the time difference values between the section time average value and the average section time, respectively. The correction voltage of the torque pattern for correcting the applied voltage of the brushless motor is generated by multiplying by a coefficient (estimated coefficient), and the correction voltage can be sequentially updated. Therefore, under pulsation during one rotation, white noise or the like is obtained by averaging processing. The pulsation can be offset by removing the pulsation. In addition, by sequentially updating the torque pattern, pulsation can be appropriately canceled and stable rotation control can be performed, so that motor vibration and noise can be suppressed, which is useful for a compressor such as an air conditioner. This has the effect.

According to the third aspect of the present invention, the predetermined coefficient in the second aspect is a reciprocal of a product of the maximum value of the section time average value, the average section time, and the number of divided sections, Since the value is smaller than the value obtained by multiplying the constant of the generated induced voltage, in addition to the effect of the second aspect, by canceling the pulsation by the correction voltage (by estimating the correction voltage), successively by the change of the predetermined coefficient. Since the correction voltage can be updated in a specific manner, and self-oscillation due to positive feedback of the updated correction voltage can be prevented, there is an effect that pulsation can be appropriately canceled.

According to the fourth aspect of the present invention, the predetermined coefficient according to the second or third aspect is represented by a function using the rotation speed of the brushless motor as a variable, and the predetermined coefficient is set to be higher as the rotation speed is higher. The predetermined coefficient is set to be smaller as the region is larger and the rotation speed is lower. In addition to the effect of claim 2 or 3, the convergence speed of the pulsation is reduced in the region of high rotation speed and the region of low rotation speed is reduced. In this case, since the accuracy of pulsation convergence can be improved, there is an effect that pulsation can be appropriately suppressed.

According to the fifth aspect of the present invention, the predetermined coefficient according to the second or third aspect is a value set in advance for each of a plurality of divided zones of the rotation control range of the brushless motor. , The predetermined coefficient is set to be larger, and the predetermined coefficient is set to be smaller in a region where the number of revolutions is lower.
In addition to the effect of
In the low rotation speed region, the accuracy of pulsation convergence can be improved, so that pulsation can be appropriately suppressed, and the memory capacity for storing the predetermined coefficient can be reduced, so that the cost can be reduced. There is.

According to a sixth aspect of the present invention, in the second aspect, the pulsation of the brushless motor is detected by calculating an average value of the time difference values for each section, and the pulsation of the brushless motor is determined according to the evaluation amount of the detected pulsation. Since the predetermined coefficient is made variable, in addition to the effect of claim 2, since the predetermined coefficient is changed according to the evaluation amount corresponding to the actual pulsation, the pulsation can be actually canceled, As a result, the pulsation convergence speed and convergence accuracy can be further improved.

According to a seventh aspect of the present invention, in the second aspect, the pulsation of the brushless motor is detected by calculating an average value of the time difference values for each section, and the evaluation amount of the detected pulsation is calculated by a plurality of values. 3. The method according to claim 2, wherein the predetermined coefficient is determined for each zone, and the predetermined coefficient is increased as the evaluation amount is larger, and the predetermined coefficient is reduced as the evaluation amount is smaller. In addition to the above effects, since the predetermined coefficient is varied in accordance with the evaluation amount corresponding to the actual pulsation, the pulsation can be actually canceled, and the convergence speed and convergence accuracy of the pulsation can be further improved. In addition, since the memory capacity for storing the predetermined coefficient is small, the cost can be reduced.

According to an eighth aspect of the present invention, in the second aspect, at the start of the generation of the correction voltage, the predetermined coefficient is set to a large value, and as the generation of the correction voltage progresses, the predetermined coefficient is set to a small value. In addition to the effect of item 2,
Although the pulsation is large at the start of the generation of the correction voltage, the large pulsation can be suppressed at a high speed because the predetermined coefficient is large, and the pulsation becomes small as the generation of the correction voltage proceeds. Therefore, there is an effect that pulsation can be suppressed with high accuracy.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a control device to which an embodiment of the present invention is applied, to which a control method of a brushless motor is applied.

FIG. 2 is a schematic chart for explaining the operation of the control device shown in FIG. 1;

FIG. 3 is a schematic memory schematic diagram for explaining an estimation coefficient S used in the control device shown in FIG. 1;

FIG. 4 is a schematic block diagram of a control device according to another embodiment of the present invention, to which a control method of a brushless motor is applied.

FIG. 5 is a schematic memory schematic diagram for explaining a pulsation evaluation amount u used in the control device shown in FIG. 4;

FIG. 6 is a schematic block diagram of a conventional control device for a brushless motor.

FIG. 7 is a schematic flowchart for explaining the operation of the control device shown in FIG. 6;

[Explanation of symbols]

Reference Signs List 3 inverter unit 4 brushless motor (sensorless DC brushless motor) 5 position detection circuit 6, 10, 11 control circuit (microcomputer) 10a position detection interval calculation unit 10b PWM signal generation unit 10c torque pattern calculation unit 10d, 11b coefficient S generation unit 10e Addition unit 10f Energization switching control unit 11a Pulsation evaluation amount u calculation unit k Induced voltage constant l Section number m Number of rotations n Estimated number (subscript) Pl Section time PPa Average section time PP1 Section time average value S Estimation coefficient (predetermined coefficient ) S (x) estimation coefficient (function; predetermined coefficient) u pulsation evaluation amount (evaluation amount) ΔPl time difference value (of section) ΔV correction voltage (torque pattern)

Claims (8)

[Claims] In a control method of a brushless motor for detecting a position of a rotor of a brushless motor and switching energization of an armature winding of the brushless motor based on the detected position, one rotation of the brushless motor is determined. It divides into a plurality of sections, measures the time of each section, calculates the average value (section time average value) for each of a plurality of rotations for each section, and calculates the average value of these section time average values (average section). Time), a time difference value between the section time average value and the average section time is calculated, and a correction voltage of a torque pattern for correcting the applied voltage of the brushless motor based on the time difference value is calculated. A method for controlling a brushless motor, wherein the correction voltage is added to a voltage applied to the brushless motor. 2. A brushless motor control method comprising: detecting a position of a rotor of a brushless motor and switching energization of an armature winding of the brushless motor based on the detected position. It divides into a plurality of sections, measures the time of each section, calculates the average value (section time average value) for each of a plurality of rotations for each section, and calculates the average value of these section time average values (average section). Time), a time difference value between the section time average value and the average section time is calculated, and the time difference value is multiplied by a predetermined coefficient (estimation coefficient) to correct the applied voltage of the brushless motor. A method for controlling a brushless motor, wherein a correction voltage for a pattern is generated and can be updated successively. 3. The predetermined coefficient is obtained by multiplying a reciprocal of a product of a maximum value of the section time average value, an average section time, and the number of divided sections by a constant of an induced voltage generated in a non-energized phase of the brushless motor. 3. The method according to claim 2, wherein the value is smaller than the value. 4. The predetermined coefficient is represented by a function using the rotation speed of the brushless motor as a variable. The higher the rotation speed is, the larger the predetermined coefficient is, and the lower the rotation speed is, the more the predetermined coefficient is. 4. The control method for a brushless motor according to claim 2, wherein the predetermined coefficient is reduced. 5. The predetermined coefficient is a value set in advance for each of a plurality of zones obtained by dividing the rotation control range of the brushless motor. The higher the number of rotations is, the larger the predetermined coefficient is. 4. The control method for a brushless motor according to claim 2, wherein the predetermined coefficient is set to be smaller as the value is lower. 6. The apparatus according to claim 2, wherein an average value of the time difference values for each section is calculated to detect a pulsation of the brushless motor, and the predetermined coefficient is varied according to an evaluation amount of the detected pulsation. The control method of the brushless motor according to the above. 7. While calculating an average value of the time difference values for each section to detect pulsation of the brushless motor, the evaluation amount of the detected pulsation is divided into a plurality of zones, and the predetermined coefficient is calculated for each zone. 3. The method of controlling a brushless motor according to claim 2, wherein the determined coefficient is increased as the evaluation amount is larger, and the predetermined coefficient is decreased as the evaluation amount is smaller. 8. The control method for a brushless motor according to claim 2, wherein the predetermined coefficient is set to a large value at the start of generation of the correction voltage, and the predetermined coefficient is set to a small value as the generation of the correction voltage progresses.