JP2002272163A - Controller of brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a controller which can apply and approximately sinusoidal voltage to a brushless motor, by adding a simple structure to a conventional inverter controller. SOLUTION: This controller of a brushless motor has a PWM operation circuit, which compares an approximately sinusoidal PWM operation waveform, generated according to a voltage command and a frequency command, with a carrier signal to generate a drive signal for a semiconductor switching device, and a V/f control inverter, to which the drive signal is applied. The output voltage of the inverter is applied to a stator coil of a brushless motor, having a position sensor sensing a pole position of a rotor. There is further provided a means, which corrects a phase angle of the PWM operation waveform, so as to start a change of a new PWM operation waveform synchronously with a timing of an output of the position sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a brushless motor (DC brushless motor), and more particularly, to a substantially sinusoidal AC voltage applied to a stator coil in synchronization with an output signal of a position detector such as a Hall sensor. The present invention relates to a control device for a brushless motor to be applied.

[0002]

2. Description of the Related Art Conventionally,
In a brushless motor, a control method is generally used in which the position of a magnetic pole of a rotor is detected by a Hall sensor and a square wave voltage is applied to a stator coil corresponding to the magnetic pole position. However, in this method, there is a problem in that a large ripple is included in the speed of the motor, so that the generated noise increases and the efficiency of the motor cannot be sufficiently increased. To solve these problems, a method of applying a voltage having a sine wave or a waveform close to a sine wave to the stator coil has been proposed. However, there is a problem that a control method is complicated and expensive.

Conventional techniques for applying a sinusoidal voltage to a stator coil include (1) a "driving device for a DC motor" described in JP-A-6-233585, and (2) JP-A-7-241095. (3) "Electric control device for brushless motor" described in JP-A-4-236190, and (4) JP-A-11-122973. Further, a “brushless motor driving device” and the like are known. However, the prior arts (1), (3) and (4) generally have a complicated configuration of the control circuit. Further, the prior art (2) has a problem that it is expensive because a position detector such as an encoder is used to detect the position of the rotor.

It is disclosed in the following publication that the timing of the voltage applied to the stator coil is changed in accordance with the rotation speed after the position of the rotor is detected in the DC brushless motor. The method is not explicitly disclosed. (5) JP-A-1-1742
No. 88, “Brushless motor driving device” (6) JP-A-3-289391, “Brushless motor”

Further, as a control device for a brushless motor, (7) Japanese Patent Application Laid-Open No. 7-337067, "Brushless motor conduction phase angle control device" (8) Japanese Patent Application Laid-Open No. 5-211
No. 796, “Brushless DC motor driving method and device” is known, but all of them detect and control the current and voltage of the motor, and have a problem that the detection unit is expensive.

Further, as a method of correcting a mounting error or the like of a position detector of a rotor of a brushless motor, the following conventional techniques exist. (9) Japanese Patent Application Laid-Open No. H11-215881 "Motor control device" However, in this prior art, it is indispensable to measure the time interval of the rotor position detection signal, so a timer is required, which increases the price. Cause.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a control device for a brushless motor which has a relatively simple and low-cost circuit configuration and generates less vibration. Another object of the present invention is to provide a control device capable of realizing V / f control by an inverter for an induction motor or the like having no position detector.

[0008]

According to a first aspect of the present invention, there is provided a semiconductor switching device comprising comparing a substantially sinusoidal PWM operation waveform created in accordance with a voltage command and a frequency command with a carrier signal. Motor having a PWM operation circuit for generating a drive signal for the motor, and a V / f control inverter to which the drive signal is applied, and a position detector for detecting an output voltage of the inverter and detecting a magnetic pole position of the rotor. In the control device for a brushless motor, the PWM signal is applied to the stator coil of the motor so that a new PWM operation waveform starts changing in synchronization with the timing of the output signal of the position detector.
It is provided with means for correcting the phase angle of the M operation waveform.

According to a second aspect of the present invention, in the control device of the first aspect, the operation of correcting the phase angle of the PWM operation waveform is performed every time the rotor rotates by (360 / N (N is an integer)) °. Things.

According to a third aspect of the present invention, in the control device according to the second aspect, when the PWM calculation waveform reaches (360 / N) ° in electrical angle before the rotor rotates (360 / N) °. The value of the PWM calculation waveform at that time is held until the rotor rotates (360 / N) ° (N is the same integer).

The invention according to claim 4 is the invention according to claim 2 or 3.
In the control device described above, the time when the rotor rotates by (360 / N) ° and the PWM calculation waveform are (360 / N) in electrical angle.
When the time when the angle reaches ° is different, the period of the PWM calculation waveform is corrected in a direction corresponding to the timing of the output signal of the position detector to create a PWM calculation waveform, and this PWM calculation waveform is used thereafter. (N is the same integer).

According to a fifth aspect of the present invention, in the control device according to any one of the first to fourth aspects, the PWM calculation waveform is corrected by using a phase angle set value according to a rotation speed of the motor. It is.

According to a sixth aspect of the present invention, in the control device according to the fifth aspect, the phase angle set value is linearly approximated with respect to the frequency command.

According to a seventh aspect of the present invention, in the control device according to the fifth aspect, the phase angle set value is approximated by a curve corresponding to the characteristics of the motor with respect to the frequency command.

According to an eighth aspect of the present invention, in the control device according to any one of the fifth to seventh aspects, the phase angle set value is determined so that the direct current of the inverter is minimized.

According to a ninth aspect of the present invention, in the control device according to the eighth aspect, the DC current of the inverter is detected while the motor is operated in a no-load state and the phase angle is slightly changed.

According to a tenth aspect of the present invention, in the control device according to any one of the fifth to ninth aspects, a phase angle set value is provided independently for forward rotation and reverse rotation of the motor.

The invention according to claim 11 is the invention according to claims 1 to 10
The control device according to any one of the above, further comprising means for detecting the frequency of the output signal of the position detector and performing feedback control so that this frequency becomes equal to the converted value of the speed command.

The invention according to claim 12 is the invention according to claims 1 to 11
The control device according to any one of the above, further comprising a selection circuit capable of selecting operation / stop of a means for correcting a phase angle of the PWM operation waveform.

According to a thirteenth aspect of the present invention, in the control device according to the twelfth aspect, the operation of the selection circuit is determined by a combination of output signals of a plurality of position detectors.

The invention according to claim 14 is the invention according to claims 1 to 13
The control device according to any one of the above, further comprising means for correcting the phase angle command value in consideration of a positional deviation between an ideal value and an actual value of the output signal of the position detector.

According to a fifteenth aspect of the present invention, in the control device according to the fourteenth aspect, the time when the rotor rotates by (360 / N) ° and the time when the PWM calculation waveform reaches (360 / N) ° in electrical angle. When different, the phase angle command value is corrected so that the timing difference between the two falls within a specified range (N is the same integer).

The invention according to claim 16 is the invention according to claims 1 to 15
The control device according to any one of the above, wherein the position detector is a Hall sensor.

The invention according to claim 17 is the invention according to claims 1 to 15
In the control device described in any one of the above, the position detector is an optical position detection unit.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the configuration and operation of the prior art will be briefly described for comparison with the embodiment of the present invention. FIG.
7 is a drive circuit diagram of a conventional brushless motor. In the figure, 100 is a DC power supply, 200 is a transistor T
1 to T6, U, V, and W are output terminals;
300 is a brushless motor, 301, 302 and 303 are stator coils, 310 is a rotor having a permanent magnet, 3
21, 322 and 323 are Hall sensors, 400 is a rotor position detection circuit, and 500 is a switching signal generation circuit.

FIG. 28 shows the driving principle of the brushless motor. The position of the magnet of the rotor 310 is detected by the Hall sensors 321 to 323, and the transistors T1 to T6 are sequentially turned on in accordance with the detected position to optimize the motor 300. A square wave voltage is applied to a simple stator coil. In this case, since many harmonics are included in the applied voltage of the square wave, problems such as a decrease in the efficiency of the motor and a generated noise are generated.

FIG. 29 shows the principle of driving a brushless motor by applying a substantially sinusoidal voltage to the stator coil. In this conventional technique, the positions of the magnets of the rotor 310 are detected by the Hall sensors 321 to 323, and the transistors T1 to T6 are switched every 60 ° so as to output a sinusoidal AC voltage calculated by a microcomputer or the like in accordance with the detected position. It is driven.

Next, FIG. 30 is a control block diagram for driving an induction motor by an inverter, where 600 is a control device, and 330 is an induction motor. In the figure, when a speed command or a voltage command is given to a soft start circuit 601, these commands are input to a PWM operation circuit 603 from a voltage command and a frequency command generation circuit 602. PWM
The arithmetic circuit 603 generates a PWM arithmetic waveform based on these commands, compares this waveform with a carrier signal, and outputs a drive signal for the switching element (transistor) of the inverter 604.

FIG. 31 is a circuit diagram of the inverter 60 shown in FIG.
4 shows the relationship between the output frequency and the output voltage, and so-called V / f control is performed. V1 and V2 are output voltage amplitudes, f1 and f2 are output frequencies, and T1 and T2 are periods. The output voltage waveform of the inverter 604 is a sine wave due to the PWM operation, and a low voltage is output in a low frequency band and a high voltage is output in a high frequency band. The phase of the output voltage waveform has no reference point at all, and is simply output continuously.

Based on these prior arts, each embodiment of the present invention will be described below in detail. FIG. 1 is a control block diagram of the brushless motor according to the first embodiment of the present invention. The control device 600A of this embodiment controls the brushless motor 340, and controls a Hall sensor 341 as a position detector for detecting a magnetic pole position of the rotor, and a position detection for detecting a position of the rotor from an output signal of the Hall sensor 341. A command waveform of the PWM operation based on the output signal of the circuit 605 (the output voltage waveform of the inverter 604,
A phase angle command correction circuit 606 for adjusting the phase angle of a PWM operation waveform) will be described below. Here, the correction circuit 606 determines that the rotor is 360 mechanical angles.
°, that is, the phase angle of the PWM calculation waveform is corrected each time the motor rotates once.

The inverter 604 has a three-phase output, and the motor 340 has a three-phase stator coil.
One Hall sensor 341 is attached to only one phase. For example, the Hall sensor 3 shown in FIG.
It is assumed that only 21 is provided. According to the control device 600A of this embodiment, only a control block having a simple configuration is added to FIG. 30, and the control device 600A can be configured simply and inexpensively.

FIG. 2 is a diagram for explaining the operation of this embodiment. Since only one Hall sensor 341 is attached to the motor 340, as shown in FIG. 2B, one signal is output from the Hall sensor 341 every time the rotor makes one rotation. When there is no output signal from the Hall sensor 341, the waveform shown in S1 is calculated by the PWM calculation circuit 603. The waveform S1 has a value that matches a predetermined V / f characteristic.

Now, as shown in FIG. 2A, the PWM operation waveform before correction (the output voltage waveform of the inverter) is represented by S1,
The amplitude is V2, and the period is T2. Hall sensor 34
Time point when the output signal of 1 changes from low to high (time t2)
In (c), the correction circuit 606 corrects the phase angle of the waveform S1 to an electrical angle of 0 °. That is, in the PWM operation circuit 603, a waveform S2 in which the phase angle of the waveform S1 is delayed is generated and used for comparison with the carrier signal. As a result, the rise of the output signal of the Hall sensor 341 and the start point of the PWM calculation waveform are synchronized, and a sine wave voltage can be applied to the optimum stator coil of the brushless motor 340.

At time t4 after the rotor makes one rotation from time t2, assuming that the phase angle of the waveform S2 has not reached the electrical angle of 0 °, the correction circuit 606 again operates the waveform S2.
2 is corrected, and the PWM operation circuit 603 shifts the phase angle of the waveform S2 to generate a waveform S3 having an electrical angle of 0 ° at time t4, which is used for comparison with the carrier signal. As a result, the PWM calculation waveform is corrected for each rotation of the rotor so that synchronization is not lost. In the above description, the change in the waveform in the period from the first time t1 to t2 is exaggerated. However, since the operation is actually started from a low speed (frequency), the motor 340 has a shock caused by the correction. Etc. hardly occur.

Next, FIG. 3 is a control block diagram showing a second embodiment of the present invention. In FIG. 1, only one Hall sensor is mounted. In the embodiment of FIG. 3, a total of three Hall sensors 351 to 353 are mounted, one for each phase of the three-phase brushless motor 350, and these Hall sensors are mounted. The output signals of the sensors 351 to 353 are input to a position detection circuit 605 in the control device 600B. The correction circuit 607
Operates so as to correct the PWM calculation waveform each time the rotor rotates 60 ° in mechanical angle (at the rising and falling timings of the output signals of the three Hall sensors).

FIG. 4 is a diagram for explaining the operation of this embodiment.
When there is no output signal of the Hall sensor, the waveform S1 shown in FIG. This waveform has a value that matches a predetermined V / f characteristic.

Now, three Hall sensors 351-353
The rotation angle of the rotor is 60 °
If it is determined in advance which part of the sine wave PWM calculation waveform to start from, the waveform S1 is corrected to the waveform S11 at the time t11 as shown in FIG. 4C. Thereafter, similarly, at times t12, t13,.
Are corrected to waveforms S12, S13,. In this way, by correcting the PWM calculation waveform,
A sinusoidal voltage can be applied to the optimum stator coil of the brushless motor 350. According to the present embodiment,
A shorter cycle (rotor angle 6
Since the correction is performed every (0 °), the motor 350 can be controlled by applying a sinusoidal voltage to the stator coil more accurately.

FIG. 5 is a control block diagram showing a third embodiment of the present invention.
4 is intended to improve the output voltage waveform. In FIG. 5, reference numeral 600C denotes a control device, and the control device 600 shown in FIG.
A is provided with a phase difference detection circuit 608. The phase difference detection circuit 608 is connected between the correction circuit 606 and the PWM operation circuit 603.

FIG. 6 is a flowchart showing the operation of the phase difference detection circuit 608. FIG. 7 is an operation explanatory diagram of FIG. Now, as shown in FIGS. 7A and 7B, it is assumed that the phase of the PWM calculation waveform is ahead of the speed of the motor 340.

In this state, according to the embodiment of FIG. 1, as shown in FIG. 7C, the phase angle of the PWM operation waveform S1 is corrected to the electrical angle 0 ° by the correction circuit 606 at time t22, and the waveform S22 Is generated. At time t25, the phase is further corrected, and a waveform S23 is generated. Therefore, at time t25, the voltage V25 of the waveform S22
Suddenly changes to the voltage 0 of the waveform S23.
The current flowing to zero suddenly changes, causing an increase in motor vibration and a decrease in efficiency.

Therefore, in the present embodiment, the above problem is solved by improving the PWM operation waveform. That is, the phase difference detection circuit 608 in FIG. 5 monitors the PWM operation waveform S22, and the output signal of the Hall sensor 341 is generated until the waveform S22 reaches 360 electrical degrees with respect to the time t22. At this time, the PWM calculation waveform is corrected (P101 to P103 in FIG. 6), and the waveform S22 has an electrical angle of 36 with respect to time t22.
When the angle reaches 0 ° (time t24 in FIG. 7D), the waveform S22 at that time is held until time t25 when the next output signal of the Hall sensor 341 is generated (P10).
4).

In other words, in other words, as shown in FIG. 7C, when the PWM calculation waveform reaches 360 ° in electrical angle before the rotor rotates 360 ° (one cycle of the output signal of the Hall sensor elapses). Holds the value of the PWM calculation waveform at that time until the rotor rotates 360 °. As a result, as apparent from FIG. 7D, at time t25, the voltage changes to the waveform S23 without abrupt change. For this reason, it is possible to prevent an increase in the vibration of the motor 40 and a decrease in the efficiency.

Next, FIG. 8 is a control block diagram showing a fourth embodiment of the present invention, in which the output voltage waveform of the inverter 604 is further improved. In FIG. 8, 6
00D is a control device, and a second PWM operation circuit 609 is added to the control device 600C of FIG. here,
The first PWM operation circuit 603 is substantially the same as the PWM operation circuit 603 in FIG.

The waveform after improvement according to the third embodiment (FIG. 7)
In the waveform (d), since there is no change in voltage during the period from time t24 to time t25, the waveform is not a complete sine wave. Therefore, in this embodiment, the state in which there is no change in voltage as described above is quickly eliminated, and the waveform is improved so that a sine wave is applied to the motor 340.

FIG. 9 is a flowchart showing the operation of the second PWM operation circuit 609 in FIG. FIG. 10 is an operation explanatory diagram of FIG. FIGS. 10B and 10C
According to the above, the PWM operation waveform S during the time t22 to t25
Comparing the time corresponding to the electrical angle of 360 ° of No. 22 with the cycle in which the output signal of the Hall sensor 341 is generated by one rotation of the rotor (360 ° in mechanical angle), the latter is longer. That is, the output signal of the Hall sensor 341 rises at time t25 which is later than time t24 corresponding to the electrical angle of 360 ° of the PWM calculation waveform S22.

Therefore, the phase difference detection circuit 608 in FIG. 8 detects a phase difference corresponding to the time from time t24 to t25 (P111 in FIG. 9), and determines the rising point of the output signal of the Hall sensor 341 as the PWM operation waveform S22. Electrical angle of 36
When it is later than 0 ° (the state of FIG. 10), FIG.
As in 0 (d), the second PWM operation circuit 609 calculates a PWM operation waveform S24 whose period is longer by a certain time than the previous time (P113). Note that the waveform S23 improved by the third embodiment is used during the period in which this calculation is performed. Then, the calculated waveform S24 is converted to a waveform S
23, and after waveform S24,
PW the waveform S25 whose period is longer than the waveform S23 by a certain time
The M operation circuit 609 calculates and uses it.

More specifically, after the time t25 in FIG. 10D, the PWM operation circuit 609 generates a waveform S24 having a period longer than the waveform S22 by a fixed time, and outputs the waveform S24 after the time t28 to output the first PWM operation circuit. Replace with the calculated waveform data of 603 (P114 in FIG. 9). By repeating this operation, the PWM operation waveform, that is, the output voltage waveform of the inverter 604 gradually changes to a clean sine wave.

The rising point of the output signal of the Hall sensor 341 corresponds to the electrical angle of 360 ° of the PWM operation waveform S22.
The second PWM operation circuit 60
9, a PWM operation waveform having a period shorter than the previous time by a fixed time is calculated (P112 in FIG. 9), and the first PWM operation circuit 6
03 is replaced with the calculated waveform data (P114). Then, when the output signal of the Hall sensor 341 is generated,
The waveform of the first PWM arithmetic circuit 603 that has been replaced is output (used for comparison with the carrier signal) (P115, P116).

Although not shown, the PWM operation waveform can be made a clean sine wave by the following method. That is, at time t25 in FIG. 10D, it is possible to know the time during which the rotor makes one rotation from time t22 to t25. If the time of one rotation (one cycle) is known, it is possible to calculate a sine wave in accordance with the cycle, so that the calculation is performed while using the waveform S23 to generate the waveform S24. After the next time t28, if the previously calculated waveform S24 is used, a clean sine wave PWM calculation waveform can be obtained after the time t28.

The calculation of the waveform S24 is performed every time the output signal of the Hall sensor 341 rises (t22, t2).
5, t28,...), But if the microcomputer being used has restrictions on the calculation speed, an error occurs between the phase angle between the waveform of the PWM calculation circuit and the output signal of the Hall sensor. It may be performed only in this case, or the calculation of the waveform corresponding to S24 may be performed in several periods.

FIG. 11 is an operation explanatory view showing a fifth embodiment of the present invention. This embodiment is realized by the control block diagram of the second embodiment shown in FIG. The operation will be described. In this embodiment, similarly to the second embodiment, the correction circuit 607 corrects the phase angle command value of the PWM calculation waveform every time the rotor rotates 60 ° in mechanical angle.

In FIG. 11 (c), P is set according to the second embodiment.
As a result of correcting the WM calculation waveform, the voltage suddenly changes from V32 to V33 at time t34. The third mentioned earlier
When the waveform is improved according to the embodiment, the same voltage value is continuously output from the time t33 to the time t34 as shown in FIG. Thus, the waveform shifts to S32, S33, S34,... Every time the rotor rotates at an angle of 60 °.

Also, in the improved waveform of FIG.
During the period from time t33 to t34 or from time t35 to t36, the voltage is kept constant, and the voltage does not become a complete sine wave. Also in this case, according to the same principle as in the fourth embodiment, the time between the electrical angle 360 ° of the PWM calculation waveform S32 between the times t32 and t34 and the time interval of the output signal of the Hall sensor due to one rotation of the rotor are set. Compare. here,
Since the time interval of the Hall sensor is longer, after the time t34, the second PWM calculation circuit 609 calculates a waveform S34 longer than the waveform S32 by a fixed time, and uses the first PWM calculation so as to use it after the time t36. Replace with the data of the circuit 603.

By repeating this operation, the PWM operation waveform can be gradually changed to a clean sine wave.
Alternatively, a clean sine wave can be obtained by calculating the period between times t32 and t34, calculating a sine wave that matches the period, and replacing the sine wave with the waveform after time t36.

Next, FIG. 12 is a diagram for supplementarily explaining the embodiment of FIG. 11, in which the horizontal axis represents the rotation angle of the rotor at which the output signal of the Hall sensor is generated, and the vertical axis represents the operation of the PWM operation circuit. The results are shown. Before the improvement of the waveform shown in FIG. 12B, even if the rotation angle of the rotor does not reach the position at every 60 °, the PWM arithmetic circuit may calculate the waveform exceeding the electrical angle of 60 °. After the improvement of the waveform according to the embodiment of FIG. 11, the operation result of the PWM operation circuit is 6 electrical degrees.
When the angle reaches 0 °, the value at 60 ° is maintained.

FIG. 13 is a control block diagram showing a sixth embodiment of the present invention. 600E is a control device, and 610 is a phase angle control device connected between the correction circuit 606 and the PWM operation circuit 603. The phase angle control device 610 can set a high-speed phase angle setting value and a low-speed phase angle setting value, and also receives a frequency command of a PWM calculation waveform.

Since the stator coil of the brushless motor has an inductance component, as the speed of the motor, that is, the frequency of the voltage applied to the motor increases, the phase angle difference between the applied voltage and the flowing current increases. Therefore, when determining the timing of the voltage to be applied to the motor based on the timing of the output signal of the Hall sensor, the phase angle of the PWM calculation waveform is changed between when the frequency (rotation speed) is low and when the frequency is high. In addition, the motor can be efficiently controlled in a wide range from a low speed to a high speed, and a large output can be generated.

FIG. 14 is a diagram for explaining the operation principle of this embodiment. In the low speed range, the set value is determined so that the phase of the PWM calculation waveform is delayed by θ52 with respect to the output signal of the Hall sensor, and in the high speed range, the phase is advanced by θ51. Between the high speed range and the low speed range, the phase angle θ is changed according to the speed (the magnitude of the frequency command).

FIG. 15 is a graph of the contents described in FIG. 14 with the frequency command on the horizontal axis and the phase angle on the vertical axis. Low-speed phase angle θ52 and high-speed phase angle θ5
A value between 1 and 1 approximates that the phase angle changes linearly. Note that the correction of the phase angle may be approximated by a curve according to the characteristics of the motor.

The phase angle control circuit 610 of FIG. 13 realizes the function of delaying or advancing the phase angle of the PWM operation waveform as described above.
It can also be realized by the correction circuits 606 and 607. Further, in a motor that performs forward / reverse rotation, a total of four phase angles may be set such as a high-speed and low-speed set value for normal rotation and a high-speed and low-speed set value for reverse rotation.

FIG. 16 is a control block diagram showing a seventh embodiment of the present invention, in which the above-mentioned phase angles θ52 and θ51 can be automatically set by a control device 600F. In this embodiment, a DC current detection circuit 611 for detecting the current of the DC bus of the inverter 604 and a setting operation circuit 612 for performing an operation for setting a phase angle according to the speed are added to the configuration of FIG. It is.

When the motor 340 is operated with no load, the phase angle of the PWM operation waveform at which the current of the DC bus and the current of the motor 340 are minimized becomes an almost optimum phase angle.
Therefore, in the present invention, the motor is operated with no load, and the phase angle is controlled so that the current of the DC bus is minimized at both low speed and high speed. FIGS. 17 and 18 are flowcharts showing the operation of this embodiment.

In FIG. 17, the motor is operated with no load and at the minimum speed (P121, P12 in FIG. 17).
2). Then, the current ID1 of the DC bus of the inverter 604 (using a transistor as a semiconductor switching element) is measured and stored as the initial phase angle of the PWM operation waveform as θ1 (P123).

Thereafter, the phase angle is gradually increased by a small amount (θ11), and each time, the current ID11 of the DC bus is measured and stored (P124).
D11 is sequentially compared (P125, P126). If it is detected in this process that the current has become the smallest, P
The process proceeds to step 127 in which the phase angle is gradually reduced. That is, the same processing as described above is performed by gradually reducing the phase angle a little (θ11) (P128 to P1).
30), the phase angle when the current is detected to be the smallest is set to a low-speed phase angle setting value θ52 (P13
1).

Thereafter, the motor is operated at the maximum speed (P
132), the high-speed phase angle setting value θ51 is determined by the same operation as that at the time of the minimum speed described above ((P133 to P14)
1).

FIG. 19 is a control block diagram showing an eighth embodiment of the present invention. In the above-described embodiments of FIGS. 1 and 3, when a load is applied to the motor, the speed of the motor decreases. Depending on the application of the motor, it is desired that the speed be substantially constant even when the load changes. Therefore, the eighth embodiment is for solving the above-mentioned problem.

A control device 600 according to the embodiment of FIG.
G is a control device 600B of FIG.
To 353, a frequency / voltage conversion circuit 613 for converting a frequency proportional to the motor speed detected from the output signals to a voltage.
And a PI operation circuit 6 that performs PI (proportional / integral) operation so as to eliminate the deviation between the output signal of the soft start circuit 601 and the output signal of the frequency / voltage conversion circuit 613.
By adding 14, feedback control is performed so that the speed of the motor 350 becomes constant. In FIG. 19, the frequency of the output signal of the Hall sensor is temporarily converted to a voltage.
The deviation from the output signal of the soft start circuit 601 may be obtained with the frequency unchanged or replaced with the period.

In each of the above-described embodiments, the brushless motor can be controlled based on the control method of the V / f-controlled inverter. Therefore, it is possible to easily return to the original inverter control. That is, if the correction function of the angle command in FIGS. 1 and 3 is stopped, it is possible to realize an inverter control device for driving an induction motor or the like. Can be diverted to equipment.

FIG. 20 is a control block diagram showing a ninth embodiment of the present invention constructed in consideration of the above points. This control device 600H includes a correction circuit 606 and a PWM circuit in control device 600A of FIG. A correction operation / stop selection circuit 615 is added to the arithmetic circuit 603. In other words, if the operation / stop selection circuit 615 selects the correction of the phase angle of the PWM calculation waveform to be effective, the above-described brushless motor control device can be configured. PWM by 615
If the correction of the phase angle of the calculated waveform is selected so as to be invalid, a control device for the induction motor by V / f control can be configured.

FIG. 21 is a control block diagram showing a tenth embodiment of the present invention. The control device 600I according to this embodiment can automatically switch between inverter control and brushless motor control in accordance with a combination of output signals of the Hall sensors 351 to 353. In detail, a combination determination circuit 616 is added to the control device 600H of FIG. 20, and one of the inverter control and the brushless motor control is selected according to the combination of the output signals of the position detection circuit 605, and the operation of the correction is performed. Stop selection circuit 6
15 is operated.

In this embodiment, one Hall sensor is attached to each of the three phases.
One or two are on (there is an output signal). If 3
If a signal corresponding to ON or OFF is output for each of them, it can be considered that the Hall sensor is not attached.

FIG. 22 shows the correspondence between the combination of the output signals of the Hall sensor and the control operation. The correspondence in FIG. 22 is determined by the combination determination circuit 616 in FIG. 21, and when the Hall sensors are attached (when the output signals of the three Hall sensors include both ON and OFF), the control of the brushless motor is performed. If the Hall sensor is not attached, it is determined that the control is the inverter control, and the selection circuit 615 selects the operation / stop of the correction of the phase angle command.

According to this embodiment, a single control device can be applied to both the control of the inverter such as an induction motor and the control of a brushless motor. The types of models can be reduced.

Next, in the brushless motor control device of the present invention, the PWM operation waveform is corrected in accordance with the output signal of the Hall sensor, and control is performed so that the voltage finally applied to the motor is sinusoidal. If the output signals of the Hall sensors are not generated at regular intervals, a clean sine wave cannot be obtained, and the noise generated from the motor may increase or the efficiency may decrease. In the eleventh embodiment of the present invention, even when output signals of the Hall sensor are not generated at regular intervals due to reasons such as poor mounting accuracy of the Hall sensor, the output signal is corrected to obtain a clean sine wave voltage. is there.

FIG. 23 shows that each of the Hall sensors has one
Fig. 4 shows a Hall sensor output signal when the Hall sensor is attached to a phase motor. With respect to the ideal output timing shown in FIG.
As shown in (b), θ6 at the position of the rotor rotation angle of 60 °
Θ120 at 0, 120 ° position, θ1 at 180 ° position
It is assumed that θ300 is shifted at positions of 240 and 300 ° at positions of 80 and 240 °, respectively.

FIG. 24 is a control block diagram of an eleventh embodiment for operating with the above-described misalignment of FIG. 23 corrected. This control device 600J is similar to control device 6 in FIG.
A correction circuit 617 is added to 00E to correct the displacement every time the rotor rotates 60 °.

That is, in the control device 600J of FIG. 24, the angle command is conventionally corrected every mechanical angle of 60 °. However, the position correction θ60, θ120, θ180, θ240, θ300 in FIG. Is added to the value for each mechanical angle of 60 °, and then the angle is corrected. Accordingly, even when the actual output signals of the Hall sensors have a deviation and are not at regular intervals as shown in FIG. 23B, the intervals can be corrected to the ideal state shown in FIG. 23A. .

FIGS. 25 and 26 are flowcharts showing a method for automatically correcting the above-mentioned positional deviation. First,
The motor is not loaded (P151 in FIG. 25), and the motor is driven at a low speed by setting all the phase angle command correction values of the PWM calculation waveform for each 60 ° of the rotation angle of the rotor to zero (P152 to P15).
7).

Next, the time of the electrical angle 60 ° of the PWM calculation waveform and the rotation angle 60 of the rotor based on the Hall sensor output signal are obtained.
The time interval of ° is detected by the microcomputer in the control circuit, and the length of both times (the electrical angle of the PWM operation waveform
Which of 0 ° and the time at which the rotor rotates 60 ° arrives earlier) is compared and detected (P158). If the angle corresponding to the difference between the compared times is smaller than the specified range, the phase angle command correction value is increased by a slight constant angle θH (P159). Conversely, if the angle is larger than the specified range, only the angle θH is added. Decrease the phase angle command correction value (P1
60), returning to step P158 and comparing the timings of the waveforms again;

If the above operation is repeated several times, the angle corresponding to the difference between the compared times falls within the specified range. The value is set as a phase angle command correction value at a rotor rotation angle of 60 ° (P161). Hereinafter, by the same procedure, the rotation angles of the rotors are 120 °, 180 °, 240 °, 30 °.
Similar processing is performed for 0 ° to obtain a phase angle command correction value in which the positional deviation has been corrected (P162 to P17 in FIG. 26).
7). In the above description, the constant angle θH is added or subtracted according to the comparison result.
Alternatively, the value may be changed depending on the number of corrections.

In each of the above embodiments, the correction of the angle command of the PWM calculation waveform using the output signal of the Hall sensor is performed as follows.
The rotation is performed when the rotation angle of the rotor reaches 60 ° or 360 °. However, the rotation angle of the rotor is not limited to these, and in general, every time the rotor rotates (360 / N (N is an integer)) °. You may go to. That is, every 90 °, 1
It may be performed every 20 degrees, every 180 degrees, etc. Also,
The position detector of the rotor is not limited to the Hall sensor, but may be replaced by an optical sensor combining a gear-shaped disk (slit disk) mounted in accordance with the position of the magnetic pole of the rotor and a photosensor or an equivalent sensor.

[0082]

As described above, the control device of the present invention is relatively simple only by adding a position detector, a phase angle command correction circuit, a phase difference detection circuit, etc. to a conventional inverter control device for driving an induction motor or the like. It can be realized simply and at low cost, and a substantially sinusoidal voltage can be applied to the brushless motor to reduce noise and improve efficiency. In addition, since it is possible to configure an inverter control device that drives the induction motor as needed, the effective use of the circuit device,
Improved versatility can be achieved.

[Brief description of the drawings]

FIG. 1 is a control block diagram showing a first embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of FIG. 1;

FIG. 3 is a control block diagram showing a second embodiment of the present invention.

FIG. 4 is an operation explanatory diagram of FIG. 3;

FIG. 5 is a control block diagram showing a third embodiment of the present invention.

FIG. 6 is a flowchart illustrating an operation of the phase difference detection circuit in FIG. 5;

FIG. 7 is an operation explanatory diagram of FIG. 5;

FIG. 8 is a control block diagram showing a fourth embodiment of the present invention.

9 is a flowchart showing an operation of the second PWM operation circuit in FIG.

FIG. 10 is an operation explanatory diagram of FIG. 8;

FIG. 11 is an operation explanatory view showing a fifth embodiment of the present invention.

FIG. 12 is a diagram for supplementarily explaining the embodiment of FIG. 11;

FIG. 13 is a control block diagram showing a sixth embodiment of the present invention.

FIG. 14 is an operation explanatory diagram of FIG. 13;

FIG. 15 is a diagram illustrating the operation of FIG.

FIG. 16 is a control block diagram showing a seventh embodiment of the present invention.

FIG. 17 is a flowchart showing the operation of the embodiment in FIG.

FIG. 18 is a flowchart showing the operation of the embodiment in FIG.

FIG. 19 is a control block diagram showing an eighth embodiment of the present invention.

FIG. 20 is a control block diagram showing a ninth embodiment of the present invention.

FIG. 21 is a control block diagram showing a tenth embodiment of the present invention.

FIG. 22 is a diagram showing a correspondence relationship between a combination of output signals of a Hall sensor and a control operation in the embodiment of FIG. 21;

FIG. 23 is a diagram showing the timing of the output signal of the Hall sensor in the eleventh embodiment of the present invention.

FIG. 24 is a control block diagram showing an eleventh embodiment of the present invention.

FIG. 25 is a flowchart showing a misregistration correction operation according to the embodiment of FIG. 24;

FIG. 26 is a flowchart illustrating a position shift correction operation according to the embodiment of FIG. 24;

FIG. 27 is a control block diagram showing a conventional technique.

FIG. 28 is an explanatory diagram of the operation in FIG. 27;

FIG. 29 is an operation explanatory diagram of FIG. 27;

FIG. 30 is a control block diagram of an induction motor.

FIG. 31 is a diagram showing a relationship between an output frequency and an output voltage of the inverter in FIG. 30.

[Explanation of symbols]

340, 350 brushless motors 341, 351-353 Hall sensors 600A, 600B, 600C, 600D, 600E,
600F, 600G, 600H, 600I, 600J
Control device 601 Soft start circuit 602 Voltage command and frequency command generation circuit 603, 609 PWM calculation circuit 604 Inverter 605 Position detection circuit 606, 607 Phase angle command correction circuit 608 Phase difference detection circuit 610 Phase angle control circuit 611 DC current detection circuit 612 Setting calculation circuit 613 Frequency / voltage conversion circuit 614 PI calculation circuit 615 Correction start / stop selection circuit 616 Combination determination circuit 617 Misalignment correction circuit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Nobuo Itoigawa 1-1 Tanabe Nitta, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture Inside Fuji Electric Co., Ltd. (72) Inventor Akio Higuchi 1st Tanabe Nitta, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture No. 1 Inside Fuji Electric Co., Ltd. (72) Inventor Makoto Hayashi 1-1-1 Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture F-term inside Fuji Electric Co., Ltd. 5H560 BB04 BB12 DA02 DA06 DA17 DA19 DB20 EB01 EC01 GG04 UA06 XA12 XA15

Claims (17)

[Claims] 1. A PWM operation circuit for generating a drive signal for a semiconductor switching element by comparing a substantially sinusoidal PWM operation waveform created according to a voltage command and a frequency command with a carrier signal, and a V / V to which the drive signal is applied.
an inverter for f control, wherein the output voltage of the inverter is applied to a stator coil of the brushless motor having a position detector for detecting a magnetic pole position of the rotor. A means for correcting the phase angle of the PWM calculation waveform so that a new change in the PWM calculation waveform starts in synchronization with the timing of the output signal of the brushless motor. 2. The brushless motor control device according to claim 1, wherein the operation of correcting the phase angle of the PWM calculation waveform is performed every time the rotor rotates by (360 / N (N is an integer)) °. Control device for a brushless motor. 3. The control device for a brushless motor according to claim 2, wherein when the PWM calculation waveform reaches (360 / N) ° in electrical angle before the rotor rotates (360 / N) °, at that point in time. A controller for a brushless motor, wherein the value of the PWM calculation waveform is held until the rotor rotates by (360 / N) ° (where N is the same integer in the claims). 4. The brushless motor control device according to claim 2, wherein the time at which the rotor rotates by (360 / N) ° and the PWM calculation waveform are (360 / N) ° in electrical angle.
When the time when the time reaches is different, the period of the PWM calculation waveform is corrected in a direction corresponding to the timing of the output signal of the position detector to create a PWM calculation waveform, and this PWM calculation waveform is used thereafter. A brushless motor control device (in the claims, N is the same integer). 5. The brushless motor control device according to claim 1, wherein the PWM calculation waveform is corrected using a phase angle set value according to a rotation speed of the motor. Control device for brushless motor. 6. The brushless motor control device according to claim 5, wherein a phase angle set value is linearly approximated with respect to a frequency command. 7. The control device for a brushless motor according to claim 5, wherein a phase angle set value is approximated to a frequency command by a curve corresponding to characteristics of the motor. 8. The brushless motor control device according to claim 5, wherein the phase angle set value is determined so that the DC current of the inverter is minimized. Control device. 9. The brushless motor control apparatus according to claim 8, wherein the DC current of the inverter is detected while the motor is operated in a no-load state and the phase angle is slightly changed. apparatus. 10. The brushless motor control device according to claim 5, wherein a phase angle set value is provided independently for forward rotation and reverse rotation of the motor. Control device. 11. The control device for a brushless motor according to claim 1, wherein a frequency of an output signal of the position detector is detected so that the frequency is equal to a converted value of the speed command. A control device for a brushless motor, comprising: means for performing feedback control. 12. The brushless motor control device according to claim 1, further comprising a selection circuit capable of selecting operation or stop of a means for correcting a phase angle of the PWM operation waveform. Characteristic brushless motor control device. 13. The brushless motor control device according to claim 12, wherein the operation of the selection circuit is determined by a combination of output signals of a plurality of position detectors. 14. The brushless motor control device according to claim 1, wherein the phase angle command value is determined in consideration of a positional deviation between an ideal value and an actual value of the output signal of the position detector. A control device for a brushless motor, comprising: means for correcting. 15. The brushless motor control device according to claim 14, wherein the time when the rotor rotates by (360 / N) ° is different from the time when the PWM calculation waveform reaches (360 / N) ° in electrical angle. A controller for a brushless motor, wherein the phase angle command value is corrected so that the difference between the timings falls within a specified range (N is the same integer in the claims). 16. The control device for a brushless motor according to claim 1, wherein the position detector is a Hall sensor. 17. The brushless motor control device according to claim 1, wherein the position detector is an optical position detection unit.