JPH08191588A - Method and equipment for controlling brushless motor - Google Patents

Abstract

PURPOSE: To make the rotational efficiency of a brushless motor excellent and to make possible the execution of an optimum rotation control by estimating the position of the rotor of the brushless motor, by correcting the estimated position in accordance with the number of revolutions of the brushless motor and by switching the current of each armature winding. CONSTITUTION: A DC power supply is switched by an inverter part 2 and impressed on armature windings U, V and W of a brushless motor 1. The respective terminal voltages Ub, Vb and Wb of the armature windings U, V and W are integrated by an integrating circuit 3a and signals of integration are compared with prescribed reference voltage by a comparing circuit 3b. A microcomputer 6 estimates the position of the rotor 1a of the brushless motor 1 on the basis of the timing of each signal of the result of comparison, corrects the estimated position in accordance with the number of revolutions of the brushless motor, obtains signals Su, Sr, Sw, Sx, Sy and Sz for drying the inverter part 2 on the basis of detection signals Uc, Vc and Wc of the corrected estimated position and switches thereby the current of each of the armature winding U, V and W.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation control technique for a DC brushless motor used for a motor of an air conditioner,
More specifically, the present invention relates to a brushless motor control method and a device therefor for improving the efficiency of rotation.

[0002]

2. Description of the Related Art When a DC brushless motor is a three-phase sensorless DC brushless motor (hereinafter referred to as a brushless motor), a control device for controlling the rotation of this brushless motor is proposed, for example, as shown in FIG. ing.

In the figure, this control device uses a DC power supply Vd as switching elements Ua, Va, Wa, Xa, Ya, Z.
The inverter section 2 which switches by a to convert into a rectangular wave voltage of a predetermined frequency and supplies the converted rectangular wave voltage to the armature winding of the brushless motor 1 and the armature windings U and V of the brushless motor 1. , W terminal voltages (including induced voltages) Ub, Vb, Wb are input, and position detection signals Uc, Vc, Wc for three phases with a predetermined phase delay are output, and these position detection signals. Each switching element Ua, Va, W of the inverter unit 2 based on Uc, Vc, Wc
The control circuit 4 outputs a drive signal for switching conduction between a, Xa, Ya, and Za.

The position detecting section 3 has input terminal voltages Ub and V.
an integrating circuit 3a for integrating b and Wb, a comparing circuit 3b for comparing the integrated signals with a predetermined voltage Vd / 2, and a voltage dividing circuit 3c for obtaining a predetermined voltage Vd / 2 from the DC power supply Vd. The position detection signals Uc, Vc of the rotor (rotor) 1a are compared with the comparison result of the comparison circuit 3b.
Output as Wc.

In this case, the voltage Vd / obtained by the voltage dividing circuit 3c
The rising and falling timings of the position detection signal are obtained by the intersection of the waveform integrated with 2 and the intersection.

The control circuit 4 not only controls the brushless motor 1 on the basis of the input position detection signals Uc, Vc, Wc, but also controls the brushless motor 1 to a target rotation speed, and, for example, performs a synchronous operation at startup. Have a function.

[0007]

By the way, in the above brushless motor control device, the position detection signals Uc, Vc, Wc are generated based on the terminal voltages U, V, W of the armature windings.
And the inverter unit 2 based on the rising and falling timings of the position detection signals Uc, Vc, Wc.
Is obtained to switch the current of the armature winding of the brushless motor 1.

However, the position detection signal U obtained by the above integration is obtained.
The timing (phase) of c, Vc, Wc becomes faster or slower according to the rotation speed of the brushless motor 1, that is, the position detection signals Uc, Vc, Wc cause the rotor 1a to rotate the brushless motor 1 most efficiently. As a result, the timing of the drive signal of the inverter unit 2 is not optimal for the rotation control of the brushless motor 1 because it does not correspond to the position.

The reason for this is that the terminal voltages U, V, W of the armature winding include the sine wave component of the induced voltage as well as the rectangular wave and PWM wave components. The integrating circuit 3a for integrating V and W has one integration constant. In other words, it is not possible to set the optimum constant of the integrating circuit 3a for all the rotation speeds of the brushless motor 1 (for example, the rotation frequency from 15 Hz to 150 Hz).

As described above, the timings of the position detection signals Uc, Vc, Wc by the position detection unit 3 are not optimal, and the timings of the position detection signals Uc, Vc, Wc are determined according to the rotation speed of the brushless motor 1. Has a problem that the efficiency of rotation control of the brushless motor 1 is deteriorated.

The present invention has been made in view of the above problems, and an object thereof is to always improve the efficiency of rotation control of a brushless motor, which is optimum regardless of the rotation speed (rotation frequency) of the brushless motor. It is an object of the present invention to provide a brushless motor control method and device capable of controlling rotation.

[0012]

In order to achieve the above object, according to the present invention, a DC power source is switched by an inverter means and applied to a plurality of armature windings of a brushless motor. The terminal voltage of the brushless motor is integrated, the integrated signal is compared with a predetermined reference voltage, the position of the rotor of the brushless motor is predicted based on the timing of the signal of the comparison result, and the predicted position is determined by the brushless motor. Compensating according to the number of rotations of the motor, obtaining a drive signal for driving the inverter means based on the corrected predicted position detection,
It is characterized in that the current of each armature winding is switched.

[0013]

With the above means, the result of comparison between the signal obtained by integrating the terminal voltage of the armature winding of the brushless motor and the predetermined reference voltage may not correspond to the accurate position of the rotor, and the position detection Even if the deviation of the position varies depending on the rotation frequency of the brushless motor, the position is predicted based on the comparison result, and the predicted position is set in advance (that is, the position is preset corresponding to the current rotation frequency). Corrected data). In other words, the position of the rotor of the brushless motor that enables the rotation of the brushless motor to be rotated most efficiently is predicted and corrected.

This prediction and correction are performed by a microcomputer, and the microcomputer outputs a drive signal for driving the inverter means based on the predicted and corrected rotor position detection timing. By driving the inverter means, excitation is sequentially applied to the armature winding of the brushless motor at an optimum timing, that is, a timing at which the brushless motor is rotated most efficiently.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION A brushless motor control method and apparatus according to the present invention is configured such that a DC power source is switched by inverter means and applied to a plurality of armature windings of a non-commutator motor (brushless motor) and each armature winding is wound. When switching the line current and controlling the rotation of the brushless motor, a signal (so-called position detection signal) obtained by comparing a signal obtained by integrating the terminal voltage of the brushless motor with a predetermined reference voltage is used to change the drive signal of the inverter means. The timing is predicted, the predicted timing is corrected according to the current rotational speed of the brushless motor, and this prediction and correction are performed by the microcomputer, while the microcomputer outputs the drive signal of the inverter means at the predicted and corrected timing. Switch to level (H level) and output, so that the rotor rotates most efficiently Switching the current in the armature winding of Rashiresumota.

Therefore, the controller of the brushless motor of the present invention has the structure shown in FIG. In the figure, the same parts as those in FIG. 6 and the corresponding parts are designated by the same reference numerals, and the duplicated description will be omitted.

In FIG. 1, in addition to the function of the control circuit shown in FIG. 6, this control apparatus includes various signals (so-called position detection signals) Uc, from the comparison circuit 3b.
The rising and falling timings of the drive signal for driving the inverter unit 2 are predicted for each rising and falling of Vc and Wc, and the predicted timing is R
It is increased / decreased (corrected) using the data of OM6a, and the output drive signal is changed to L level (or H level) at the corrected timing.
It has a microcomputer 6 for switching to a level).

The brushless motor 1 is installed in the ROM 6a.
Multiple data Δθ corresponding to the number of rotations (rotation frequency)
(Correction data) is stored in advance, and this correction data Δθ is determined based on the phase shift of each position detection signal Uc, Vc, Wc that occurs corresponding to the rotation frequency of the brushless motor 1. .

Next, the control method in the controller of the brushless motor will be described in detail with reference to the time chart of FIG. 2 and the flowcharts of FIGS. 3 to 5. First, the armature winding of the three-phase brushless motor 1 will be described. It is assumed that the brushless motor 2 is rotating at a predetermined number of revolutions by sequentially exciting the specific phases of the above, and has entered, for example, the nth rotation (n; integer).

Then, the microcomputer 6 has the position detection signals Uc, Vc, Wc from the comparison circuit 3b (see FIG. 2).
(Shown in (a) to (c)) is input, and the microcomputer 6 detects rising edges and falling edges of the input signals Uc, Vc, Wc.

When the rising edge of the input signal Uc is detected, the process proceeds from step ST1 to step ST2 to measure the current interrupt time (time when the electrical angle is 0 degree) t1n and store it in the internal storage means.

Thereafter, the predicted time T2n of the drive signal for conducting the transistors Ua, Va, Wa, Xa, Ya, Za of the inverter section 2 in a predetermined manner is calculated and set in the prediction timer (step ST3). . In particular,
As shown by the arrows in FIG. 2, the times t1n and (n
-1) Time t1 (n- at the electrical angle of 0 degree detected at the rotation time)
1) divided into 6 times (t1n-t1 (n-
1)) / 6 is calculated.

This calculation time (t1n-t1 (n-1))
/ 6, the data Δθ read from the ROM 6a according to the current rotation speed (current rotation frequency) of the brushless motor 1.
The predicted time T2n corrected by this increase / decrease
Is calculated (indicated by the arrow in FIG. 2). The current rotation speed is calculated based on the already detected time.

Subsequently, when the falling edge of the position detection signal Wc is detected, steps ST4 to ST5
To the current interrupt time (electrical angle of 60 degrees) t
2n is measured and stored in the internal storage means.

Thereafter, the predicted time T3n of the drive signal for conducting the transistors Ua, Va, Wa, Xa, Ya, Za of the inverter unit 2 in a predetermined manner is calculated and set in the prediction timer (step ST6). .

Similarly, when the rising edge of the position detection signal Vc is detected, the process proceeds from step ST7 to step ST8 to measure the current interrupt time (time of 120 electrical degrees) t3n and store it in the internal storage means. . Then, the transistors Ua, Va, and
The predicted time T4n of the drive signal for conducting Wa, Xa, Ya, and Za in a predetermined manner is calculated and set in the predicted timer (step ST9).

When the falling edge of the position detection signal Uc is detected, the process proceeds from step ST10 to step ST11, and the interrupt time of this time (time of electrical angle 180 degrees) t4
n is measured and stored in the internal storage means. Then, each transistor Ua, Va, Wa, Xa of the inverter unit 2
The predicted time T5n of the drive signal for conducting Ya and Za in a predetermined manner is calculated and set in the prediction timer (step ST9).

When the rising edge of the position detection signal Wc is detected, the process proceeds from step ST13 to step ST14, and the interrupt time of this time (time of electrical angle 240 degrees) t5
n is measured and stored in the internal storage means. Then, each transistor Ua, Va, Wa, Xa of the inverter unit 2
The predicted time T6n of the drive signal for conducting Ya and Za in a predetermined manner is calculated and set in the prediction timer (step ST15).

When the edge of the position detection signal Wc does not rise, that is, the position detection signal V which is the last in one rotation is detected.
If it is the falling edge of c, the process proceeds from step ST13 to step ST16, and the current interrupt time (time at an electrical angle of 300 degrees) t6n is measured and stored in the internal storage means. Then, each transistor U of the inverter unit 2
The predicted time T1 (n + 1) of the drive signal for predetermined conduction of a, Va, Wa, Xa, Ya, Za is calculated and set in the prediction timer (step ST17).

The interrupt routine shown in FIG. 5 is executed together with the setting of the prediction timer described above. For example, when the prediction time T2n is set in the prediction timer in step ST3, the process advances from step ST20 to ST21 due to the time-up of the prediction timer. Step ST21
In, the output drive signal Sx is turned off (L level) and the output drive signal Sy is turned on (H level) (shown in FIGS. 2G and 2H). The other output drive signals Su, Sv, Sw and Sz are set to the same level as before.

Similarly, when the prediction time T3n is set in the prediction timer in step ST6,
When the prediction timer is up, the process proceeds from step ST22 to ST23. In step ST23, the output drive signal Sw is turned off (L level) and the output drive signal Su is turned on (H level) (FIG. 2 (f)).
And (d)).

When the prediction time T4n is set in the prediction timer in step ST9, the process advances from step ST24 to ST25 due to the time up of the prediction timer. In step ST25, the output drive signal Sy is turned off (L level) and the output drive signal Sz is output.
Is turned on (H level) (shown in FIGS. 2 (h) and 2 (i)).

Predicted time T5n in step ST12
Is set in the prediction timer, the process advances from step ST26 to ST27 due to the time up of the prediction timer. In step ST27, the output drive signal Su is turned off (L level) and the output drive signal Sv is set.
Is turned on (H level) (shown in FIGS. 2D and 2E).

Predicted time T6n is determined in step ST15.
When is set in the prediction timer, the process advances from step ST28 to ST29 due to the time up of the prediction timer. In step ST29, the output drive signal Sz is turned off (L level) and the output drive signal Sx is set.
Is turned on (H level) (shown in FIGS. 2 (i) and 2 (g)).

Predicted time T1 in step ST17
When (n + 1) is set in the prediction timer, steps ST28 to S
Proceed to T30. In step ST30, the output drive signal Sv is turned off (L level) and the output drive signal Sw is turned on (H level) (shown in FIGS. 2E and 2F).

In this way, the input position detection signals Uc, V
Based on rising and falling of c and Wc, rising of drive signals Su, Sv, Sw, Sx, Sy and Sz,
Predict the fall (H, L level timing) time,
This predicted time is corrected by the data of the ROM 6a according to the current rotation speed of the brushless motor 1. Moreover, by the prediction and correction, the timing of the drive signal is obtained such that the rotor 1a of the brushless motor 1 is rotated most efficiently and the optimum rotation efficiency is obtained regardless of the rotation frequency of the brushless motor 1.

Therefore, the current in the armature winding of the brushless motor 1 is switched so as to rotate the rotor most efficiently, and as a result, the efficiency of rotation control of the brushless motor 1 can always be kept good. it can.

In this embodiment, the data of the ROM 6a is used to correct the timing of the drive signal. However, the correction data is calculated using an equation, and, for example, the position detection signals Uc, Vc, Wc are calculated. May be used.

[0039]

As described above, according to the present invention, the DC power source is switched by the inverter means to be applied to the plurality of armature windings of the non-commutator motor (brushless motor) and each armature winding. When switching the line current and controlling the rotation of the brushless motor, a signal (so-called position detection signal) obtained by comparing a signal obtained by integrating the terminal voltage of the brushless motor with a predetermined reference voltage is used to change the drive signal of the inverter means. The timing is predicted, the predicted timing is corrected according to the current rotation speed of the brushless motor, and the prediction and correction are performed by the microcomputer.
Since this microcomputer switches the drive signal of the inverter means to L level (H level) and outputs it at the predicted and corrected timing, the armature winding is arranged so that the rotor of the brushless motor rotates most efficiently. It becomes possible to switch the current of the line, and as a result, the rotation efficiency of the brushless motor can always be made good, and there is a useful effect that optimum rotation control can be performed regardless of the rotation speed of the brushless motor. .

[Brief description of drawings]

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

FIG. 2 is a schematic time chart diagram for explaining the operation of the controller for the brushless motor shown in FIG.

FIG. 3 is a schematic flowchart illustrating the operation of the controller for the brushless motor shown in FIG.

FIG. 4 is a schematic flowchart illustrating the operation of the brushless motor control device shown in FIG. 1.

5 is a schematic flow chart diagram for explaining the operation of the controller of the brushless motor shown in FIG. 1. FIG.

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

[Explanation of symbols]

1 Brushless Motor (Sensorless DC Brushless Motor) 1a Rotor (Rotor) 2 Inverter Section 3 Position Detection Section 3a Integration Circuit 3b Comparison Circuit 3c Voltage Dividing Circuit 4 Control Circuit 5 Driver Section 6 Microcomputer 6a ROM U, V, W Armature Winding (for brushless motor 1) Ua, Va, Wa, Xa, Ya, Za Transistor (for inverter unit 2) Ub, Vb, Wb Terminal voltage (armature winding U, V, W)
Uc, Vc, Wc Position detection signals (of rotor 1a)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiyuki Ohara 1116 Suenaga, Takatsu-ku, Kawasaki City, Kanagawa Prefecture Fujitsu General Limited

Claims (4)

[Claims] 1. A DC power source is switched by an inverter means and applied to a plurality of armature windings of a brushless motor,
The terminal voltage of each armature winding is integrated, the integrated signal is compared with a predetermined reference voltage, and the position of the rotor of the brushless motor is predicted based on the timing of the signal of the comparison result. The predicted position is corrected according to the rotation speed of the brushless motor, a drive signal for driving the inverter means is obtained based on the corrected predicted position detection, and the current of each armature winding is switched. And a method for controlling a brushless motor. 2. A DC power source is switched by an inverter means and applied to a plurality of armature windings of a brushless motor,
The terminal voltage of each armature winding is integrated, the signal obtained by the integration is compared with a predetermined reference voltage obtained by dividing the DC power supply, and the result is input to a microcomputer. For each rising and falling timing of the signal of the input comparison result, the position of the rotor of the brushless motor is predicted, and the predicted position is converted into data corresponding to the current rotation speed of the brushless motor from preset data. A method of controlling a brushless motor, wherein the brushless motor is corrected on the basis of the corrected position and a time signal of the corrected predicted position is operated to obtain a drive signal for driving the inverter means. 3. A DC power source is switched by an inverter means and applied to a plurality of armature windings of a brushless motor,
The terminal voltage of each armature winding is integrated, the integrated signal is compared with a predetermined reference voltage, and the position of the rotor of the brushless motor is detected based on the comparison result, and based on the detection signal of the position. In the controller of the brushless motor, which sequentially controls the currents of the armature windings to control the rotation of the brushless motor at a predetermined rotation speed, the drive signal of the inverter means based on the detection signal of the position of the rotor. With storage means for storing the data for correcting the timing of the brushless motor corresponding to the rotation speed of the brushless motor, and for each timing of the detection signal of the position, while predicting the position of the rotor of the brushless motor, The predicted position is corrected by the data corresponding to the current rotation speed of the brushless motor in the data of the storage means, and the corrected predicted position Control means for operating an internal timer on the basis of the time to obtain the timing of the drive signal of the inverter means, and driving the inverter means by the drive signal obtained by the control means to drive each of the armature windings. A controller for a brushless motor, characterized in that the current is sequentially switched. 4. A DC power source is switched by an inverter means and applied to an armature winding of a three-phase brushless motor,
The terminal voltage of each armature winding is integrated, the integrated signal is compared with a predetermined reference voltage, the position of the rotor of the brushless motor is detected based on the comparison result, and a detection signal of the position is input. In the controller of the brushless motor, which controls the rotation of the brushless motor at a predetermined rotation speed by driving the inverter means by the microcomputer to sequentially switch the currents of the armature windings, the microcomputer is configured to The brushless motor has a storage unit that stores data for correcting the timing of the drive signal in correspondence with the rotation speed of the brushless motor, and rotates the brushless motor at each rising and falling timing of the detection signal at the position. The position of the child is predicted, and the predicted position is stored in the data of the storage means. The data corresponding to the current rotation speed of the serial motor is read out and corrected, the internal timer is operated based on the time of the corrected predicted position to execute the interrupt processing, and the output timing of the drive signal of the inverter means by the interrupt processing. The controller for a brushless motor is characterized in that the inverter means is driven by a drive signal from the microcomputer to sequentially switch the currents of the armature windings.