JPH07111795A - Controlling equipment for brushless dc motor - Google Patents

Abstract

PURPOSE:To make it possible to correct the misalignment of energization phase according to number of revolutions and load torque, by detecting the number of revolutions of a rotor, and correcting the position of the rotor according to the number of revolutions. CONSTITUTION:A microcomputer 12 reads a timer value and a phase correction value from a timer 7 and a storage unit 8 and further calculates the number of revolutions of a rotor 1 according to a specified arithmetic operation program. It reads acorrection phase value to correct position detection signals D1-D3 from the map storage area in the storage unit 8 according to the number of revolutions and a load torque detected by a torqtue detector 9, and calculates a time corresponding to the correction phase value. Based on the position detecting signals D1-D3 corrected according to the resultant time, the microcomputer 12 then outputs six-phase energization switching signals J1-J6 to an energization switching circuit 3. First driving transistors 3a, 3b, 3c and second driving transistors 3d, 3e, 3f, are switched and controlled according to the energization switching signals J1-J6, and the energization of coils 2a, 2b, 2c is thereby controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless DC motor control device for detecting the position of a rotor without a sensor.

[0002]

2. Description of the Related Art Japanese Patent Publication No. 5-34916 discloses a method of driving a brushless DC motor without a sensor using an integrating circuit. This method detects the position of the rotor by the position detection circuit shown in FIG. 10 and switches the energization switching signals J1 to J6 at each edge of the position detection signals D1 to D3 shown in FIG. The fact that it is the same as the position detection signals D1 to D3 is used.

[0003]

However, in the above method, the phases of the position detection signals D1 to D3 change depending on the rotation speed and the load torque, and the phases of the energization switching signals J1 to J6 change accordingly. If the number of rotations is low as the cause of this, the output φa of the circuit F1 shown in FIG.
This is because φc has characteristics such as φT shown in FIG. When the rotation speed is high, the phase of φT is further delayed due to the influence of the capacitors C1 to C3 incorporated in the position detection circuit. When the load torque is high, the width dφ (see FIG. 13) of the spike voltage appearing in the voltages Va to Vc input to the position detection circuit becomes wide, and the position detection signal D1 is generated.
This is because the phase of ~ D3 shifts to the (-) side.
When the load torque is low, there is no problem because the width dφ of the spike voltage is narrow. As described above, the conventional method has a problem in that the energization phase is deviated, the motor efficiency varies depending on the rotation speed and the load torque, and in the worst case, the motor cannot be driven. The present invention has been made to solve the above problems, and an object of the present invention is to provide a controller for a brushless DC motor that corrects the deviation of the energization phase according to the rotation speed and the load torque. is there.

[0004]

In order to achieve the above object, a brushless DC motor control apparatus according to the present invention is shown in FIG.
As shown in (a), rotor position detecting means 100 for detecting the position of the permanent magnet type rotor, and energization switching for switching energization to a plurality of armature windings according to the output of the rotor position detecting means 100. In the controller of the brushless DC motor for controlling the rotation of the rotor, the rotation speed detecting means 10 for detecting the rotation speed of the rotor.
2 and correction means 103 for correcting the output of the rotor position detection means 100 according to the rotation speed output by the rotation speed detection means 102. Also, FIG.
As shown in (b), the rotor position detecting means 100 for detecting the position of the permanent magnet type rotor, and the energization of a plurality of armature windings are switched according to the position output by the rotor position detecting means 100. In a controller of a brushless DC motor that includes an energization switching unit 101 and controls the rotation of the rotor, a rotation speed detection unit 102 that detects the rotation speed of the rotor and a torque that detects a load torque of the rotor. The detection means 104 and the correction means 105 for correcting the output of the rotor position detection means 100 based on the load torque output by the torque detection means 104 and the rotation speed output by the rotation speed detection means 102. It is characterized by that.

[0005]

In the controller of the brushless DC motor having the above-described structure, the energization switching means 101 is based on the rotor position output by the rotor position detecting means 100 corrected by the correcting means 103 according to the number of rotations. Controls the rotation of the rotor by switching energization to a plurality of armature windings, and rotation control can be performed at a constant energization timing in all rotation speed regions. Further, the energization switching unit 101 switches energization to a plurality of armature windings based on the position of the rotor output by the rotor position detection unit 100 corrected by the correction unit 105 according to the rotation speed and the load torque. Since the rotation control of the rotor is performed, the rotation control can be performed at a constant energization timing in the entire rotation speed range and load torque range.

[0006]

FIG. 2 is a block diagram showing a schematic structure of a controller for a brushless DC motor according to the present invention. In the figure, reference numeral 1 is a rotor constituted by a permanent magnet of one magnetic pole pair, and a field magnetic flux is linked to the three-phase coils 2a, 2b, 2c. Reference numeral 3 denotes an energization switching circuit that switches energization to the coils 2a, 2b, 2c. The first driving transistors 3a, 3b, 3c and the second driving transistor 3d,
3e, 3f, first diodes 4a, 4b, 4c and second diodes 4d, 4e, 4f, and a coil 2a, 2b from the DC power source 5 in response to an energization switching signal output from a micro computer 12 described later. , 2c and the current return path from the coils 2a, 2b, 2c to the DC power supply 5 are switched.

Reference numeral 6 is a position detector for detecting the rotational position of the rotor 1. When the rotor 1 is rotating at a speed equal to or higher than a predetermined speed, the position detector 6 detects the counter electromotive force Va, V appearing at each of the A terminal, B terminal and C terminal of the three-phase coils 2a, 2b, 2c.
The rotational position of the rotor 1 is detected by b and Vc, and position detection signals D1, D2 and D3 corresponding to the rotational position are output. Reference numeral 7 denotes a timer, which includes a free-running timer and a transfer unit that transfers the timer value at the moment when the position detection signals D1 to D3 change to the storage device 8. The storage device 8 includes a map storage unit that stores the corrected phase value as a map, and a timer 7.
The timer storage unit stores the timer value of. Reference numeral 9 denotes a torque detector, which detects the load torque of the rotor 1 by the torque sensor 10. The torque detection may be performed by converting a current value read by the ammeter 11a provided in the power supply circuit 11 into a load torque. The timer 7 and the storage unit 8 are respectively connected to the microcomputer 12 by a bus.

The microcomputer 12 reads the timer value and the phase correction value from the timer 7 and the storage unit 8 and calculates the rotation speed of the rotor 1 according to a predetermined calculation program. The correction phase value for correcting the position detection signals D1 to D3 is read from the map according to the rotation speed and the load torque detected by the torque detection unit 9, and the time corresponding to the correction phase value is calculated. Then, the six-phase energization switching signals J1 to J6 output based on the position detection signals D1 to D3 corrected by this time are output to the energization switching circuit 3. The first drive transistors 3a, 3b, 3c and the second drive transistors 3d, 3e, 3f are switching-controlled by the energization switching signals J1 to J6, and the coils 2a, 2
The energization to b and 2c is controlled.

FIG. 3 shows the contents of the map of the correction phase values stored in the map storage section of the storage section 8.
The amount of phase shift of the position detection signals D1 to D3 of the rotor 1, which is affected by the rotation speed and the load torque, is uniquely determined from the relationship between the rotation speed and the load torque. Therefore, the map of the correction phase value is a two-dimensional map based on the rotation speed and the load torque. The position detection signals D1 to D3 are corrected by "phase lead" or "phase delay", and the energization switching signals J1 to J are performed.
By controlling the timing of outputting 6, it is possible to always obtain a constant energization phase angle.

FIG. 4 shows position detection signals D1 to D of the rotor 1.
3 and energization switching signal J1 when "phase delay" correction is performed
7 is a time chart of J6. In this case, after the rising and falling edges (locations t1 to t11 in the figure) of the position detection signals D1 to D3 are input, the rotor 1
The correction phase value of the map is read according to the number of revolutions and the load torque, and the energization switching signals J1 to J6 are turned on / off after the time corresponding to the correction phase value has passed (t1 'to t11' in the figure). .

Further, FIG. 5 shows the position detection signal D1 of the rotor 1.
6 is a time chart of energization switching signals J1 to J6 when "phase lead" correction is performed with .about.D3. In this case, the timing at which the energization switching signals J1 to J6 are output is more temporal than the timing at which the rising and falling edges (locations t1 to t11 in the figure) of the position detection signals D1 to D3 are input. Since it becomes faster, it is necessary to perform "predictive control". In order to perform the "prediction control", first, the time when the rising and falling edges of the position detection signals D1 to D3 occur is stored as a history. Then, the correction phase value of the map is read according to the rotation speed of the rotor 1 and the load torque, and the energization switching signals J1 to J6 are turned on at the timings when the time corresponding to the correction phase value is added to the stored history. -Turn it off (t2 'to t11' in the figure). In the case of the above “predictive control”, it is not necessary to specify the history to be stored. For example, when the energization control is performed at the timing "t9 '" in FIG. 4, an infinite number of patterns are conceivable as shown below.

(Pattern 1) The time difference between the timings "t7" and "t8" is set to "t '", and the time corresponding to the correction phase value ((-) time in this case) is added to "t". ". "T" is added to the timing of "t8", the timing of "t9 '" is calculated, and the energization switching signal J
1 to J6 are turned on / off at the timing of "t9 '".
Then, the above processing is repeated after the timing "t10 '".

(Pattern 2) The time difference between the timings "t6" and "t8" is set to "t '", and the time corresponding to the correction phase value ((-) time in this case) is added to "t". ". "T""is added to the timing of" t7 ", the timing of" t9 '"is calculated, and the energization switching signal J
1 to J6 are turned on / off at the timing of "t9 '".
Then, the above processing is repeated after the timing "t10 '".

(Pattern 3) The time difference between the timings "t2" and "t3" is "t '", and the time corresponding to the correction phase value ((-) time in this case) is added to "t". ". "T" is added to the timing of "t8", the timing of "t9 '" is calculated, and the energization switching signal J
1 to J6 are turned on / off at the timing of "t9 '".
Then, the above processing is repeated after the timing "t10 '".

The above "prediction control" can be applied not only to "phase lead" correction but also to "phase delay" correction. Therefore,
"Predictive control" regardless of "phase lead" and "phase delay"
By performing, the control method is unified and effective.
In this case, as described above, which of the innumerable patterns is selected becomes a problem in relation to the rotation unevenness of the rotor 1. However, this rotation unevenness is almost equal at the same rotation angle of the rotor 1, that is, at the same phase.
For example, in FIG. 4 and FIG. 5 described above, “t1” to “t7”
In the case of a two-pole motor in which the rotor 1 makes one rotation, the time from "t1" to "t2" one rotation before and "t" of the next rotation
It is almost equal to the time from "7" to "t8". Therefore, as the history used in the “prediction control”, the one before one rotation of the rotor 1 may be used. Specifically, when obtaining the timing of "t9 '" in FIGS. 4 and 5, if the (Pattern 3) for obtaining the time difference between the timings "t2" and "t3" at which the rotation phases are the same is selected. Good.

FIG. 6 shows the relationship between the position detection signals D1 to D3, the timer 7 and the storage device 8. Figure 6
(A) shows the addresses of the storage device 8 in which the changes in the position detection signals D1 to D3 and the timings at that time are automatically transferred and stored, and FIG. “M1” to “M6” and “N1” to “N6” represent addresses, and “m1” to “m” are shown.
6 ”and“ n1 ”to“ n6 ”respectively indicate the stored contents.

FIG. 7 is a flowchart for implementing the above (Pattern 3). The flow chart is executed by the processing of the microcomputer 12. When the process is started, the contents of the timer 7 and the storage device 8 are cleared in step 10 and the timer 7 is initialized. In step 11, positioning is performed by energizing a specific phase of the coil for a certain period of time to fix the position of the rotor 1. Subsequently, in step 12, another braking operation processing for setting a timer for another braking operation is performed. In step 13, the energization switching signals J1 ...
J6 is output at the timing shown in FIG. "T
Each timing of "1" to "t11" is controlled according to a preset sequence using the timer 7. Here, the energization switching signals J1 to J6 are output regardless of the input of the position detection signals D1 to D3. Each timing of "t1" to "t11" is determined, the process proceeds to step 14 at each timing, and is updated with the contents of the output energization switching signals J1 to J6.

In step 15, the energization switching signals J1 ...
According to the contents of J6, the addresses "N1" to "N" of the storage device 8
6 ”is updated (addresses“ N1 ”to“ N ”
6 "is the position detection signals D1 to D3 of the rotor 1 before one rotation.
Rising edge and falling edge (t1 in FIG. 11)
The timing from t11 is input). Then, the update of the stored contents is performed according to FIG. Step 16
Then, it is determined whether or not the rotor 1 has rotated two times or more. If the rotor 1 does not rotate more than 2 times, the address "N1" ~
This is because the stored content of "N6" is not fixed. Rotor 1
If it is determined that the rotor has rotated 2 or more revolutions, it is determined in step 17 that the rotor 1 has reached the predetermined number of revolutions, the other braking operation is ended, and the operation shifts to the self-controlling operation.

In step 18, the timer for the self-control operation is set, and the content of the energization switching signals J1 to J6 is changed from the content of the energization switching signals J1 to J6 at the end of the other control operation (FIG. 4 and "t1 '" in FIG.
~ "T11 '") is set. This timing is set according to FIG. 9 by reading the correction phase value according to the rotational speed of the rotor 1 and the load torque from the correction phase value map (FIG. 3). The correction term shown in FIG. 8 is calculated by correction term = correction phase value / (3 × rotation number × p) (where p is the number of poles of the motor).

In step 19, the set timings "t1 '" to "t11'" are determined, and in step 20, the energization switching signals J1 to J6 output at each timing.
The stored contents are updated with the contents (patterns shown in FIGS. 4 and 5). Then, in step 21, from the contents of the updated energization switching signals J1 to J6, next, energization switching signals J1 to J6.
Timing of changing the contents of 6 (“t” in FIGS. 4 and 5).
1 '"to"t11'") are set. This timing is set according to FIG. 9 by reading the correction phase value according to the rotational speed of the rotor 1 and the load torque from the correction phase value map (FIG. 3).

In the following step 22, the stored contents of the addresses "N1" to "N6" of the storage device 8 are updated according to the contents of the updated energization switching signals J1 to J6 (rotation to the addresses "N1" to "N6"). Timings of rising and falling edges (positions of t1 to t11 in FIG. 11) of the position detection signals D1 to D3 of the child 1 before one rotation are input). This storage content is updated according to FIG. Then, the process returns to step 19 and the processes up to step 22 are repeated.

The actual operation according to the above flow chart is
This will be specifically described below with reference to the time chart of FIG. However, after shifting to self-control, at least the rotor 1
Is supposed to make one revolution. Here, it is assumed that the contents of the energization switching signals J1 to J6 are set to the state of "t8 '" in the process of step 20. In the processing of step 21, the next timing "t9 '" is obtained from the following equation according to FIG. t9 '= m1 + n3-n1 + correction term = t7 + t3-t1 + correction term Then, in step 22, the timing of "t7" is saved in the address "N1" according to FIG. 8 and the timing of one revolution of the rotor 1 is stored. .

Then, returning to step 19, it is judged whether or not the timing of "t9 '" has come. In step 21, the next timing "t10 '" is obtained from the following equation according to FIG. t10 '= m2 + n4-n2 + correction term = t8 + t4-t2 + correction term Then, in step 22, the timing of "t8" is saved in the address "N2" according to FIG. 8 and the timing of one revolution of the rotor 1 is stored. .

If the above operation is repeated thereafter, the position of the rotor 1 can be corrected, and the rotor 1 cannot be driven in the low speed rotation region, and the energization phase angle shifts due to the influence of the load torque and the rotation speed of the motor, resulting in a decrease in efficiency. Can be prevented.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to a complaint.

FIG. 2 is a block diagram showing a schematic configuration of a controller for a brushless DC motor.

FIG. 3 is a diagram showing the contents of a map of correction phase values.

FIG. 4 is a time chart in the case of phase delay correction.

FIG. 5 is a time chart in the case of phase lead correction.

FIG. 6 is a diagram showing a relationship between a position detection signal, a timer, and a storage device.

FIG. 7 is a flowchart showing an outline of correction processing.

FIG. 8 is an explanatory diagram showing a change in stored content.

FIG. 9 is an explanatory diagram showing timing settings for correction.

FIG. 10 is a position detection circuit diagram.

FIG. 11 is a time chart in the case where conventional correction is not performed.

FIG. 12 is a characteristic diagram showing the relationship between the rotational speed, the load torque, and the output phase.

FIG. 13 is a waveform diagram showing a spike voltage appearing at the input to the position detection circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 rotor 2a, 2b, 2c coil 3 energization switching circuit 6 position detection part 7 timer 8 storage device 9 torque detection part 10 torque sensor 12 microcomputer 100 rotor position detection means 101 energization switching means 102 rotation speed detection means 103, 105 Correction means 104 Torque detection means

Claims (2)

[Claims] 1. A rotor position detecting means for detecting a position of a permanent magnet type rotor, and an energization switching means for switching energization to a plurality of armature windings in accordance with an output of the rotor position detecting means. A controller for a brushless DC motor that controls the rotation of the rotor, wherein the rotor position is detected according to the rotation speed detection unit that detects the rotation speed of the rotor and the rotation speed that the rotation speed detection unit outputs. A controller for a brushless DC motor, comprising: a correction unit that corrects the output of the detection unit. 2. A rotor position detecting means for detecting a position of a permanent magnet type rotor, and an energization switching means for switching energization to a plurality of armature windings in accordance with an output of the rotor position detecting means. A controller for a brushless DC motor that controls the rotation of the rotor, wherein the rotation speed detection means detects the rotation speed of the rotor, the torque detection means detects the load torque of the rotor, and the torque detection means. A controller for a brushless DC motor, comprising: a correction unit that corrects the output of the rotor position detection unit based on the load torque output by the rotation number and the rotation speed output by the rotation number detection unit.