JPH07303391A - Method and apparatus for controlling brushless motor - Google Patents

Abstract

PURPOSE:To stabilize the operation of a motor by estimating the timing of switching the energization of each armature winding of a brushless motor from a position detecting signal which has no lag in phase. CONSTITUTION:In the case of a three-phase brushless motor 1, for example, a phase detecting section 7 outputs a position detecting signal based on the terminal voltages (120 deg. out of phase with each other) U, V, W of armature windings. The timings of a rise edge and a fall edge of this position detecting signal are detected and then edges of the next position detecting signal are estimated based on the measured time between the timings of the rise edge and the fall edge of the first position detecting signal. Based on the measured time between the rise edge and the fall edge of the first position detecting signal and the timings of the next position detecting signal, edges of the remaining position detecting signals are estimated. By the time right before the brushless motor 1 is switched from the synchronous operation to the operation based on the position detecting signals, the energization of each armature winding is switched using a position detecting signal which is estimated based on the one right before the operation mode is switched.

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 particularly, the present invention relates to a brushless motor control method and apparatus for simplifying a circuit for detecting the position of a rotor and smoothing the transition of operation modes.

[0002]

2. Description of the Related Art In controlling the rotation of a DC brushless motor (hereinafter referred to as a brushless motor), for example, in the case of a three-phase brushless motor, conventionally, for example, a control device shown in FIG. 9 is used.

That is, this control device includes an inverter section 2 for switching a power source Vcc obtained by converting an AC power source into a direct current by an AC / DC converter and applying it to three armature windings of a brushless motor 1, Terminal voltage of brushless motor 1 (voltages having different phases by 120 degrees; induced voltage) U, V, W
Position detection unit 3 for detecting the position of the rotor 1a based on
And a control signal of the inverter unit 2 for switching the energization of each armature winding of the brushless motor 1 in a predetermined manner and switching each armature winding in a predetermined manner based on the position detection signal from the position detection unit 3. While outputting a chopping signal for chopping a predetermined control signal of the control signal at a predetermined frequency (microcomputer) 4
In the control device having the above configuration, a chopping section 5 for chopping and outputting the control signal and a driver section 6 for driving the switch means of the inverter section 2 by the control signal including the chopped signal are provided. When the brushless motor 1 is started, the brushless motor 1 is synchronously operated for a predetermined time, but after the predetermined time has elapsed, the brushless motor 1 is rotationally controlled based on the position detection signal of the rotor 1a of the brushless motor 1 (position detection operation). Switch to).

When the synchronous operation of the brushless motor 1 is performed for a predetermined time, as shown in FIG. 10, the brushless motor 1
The terminal voltages U, V, W of the respective armature windings are obtained, and the position detection signals A1, B1, C1 of the rotor 1a are obtained from the position detection section 3 based on these terminal voltages U, V, W. . In the figure, a is a spike voltage. Further, various circuits have been proposed as the position detecting unit 3 that outputs the position detection signals A1, B1, C1, and therefore the description of the circuits will be omitted.

When the brushless motor 1 is operated based on position detection, the control circuit 4 controls the position detection signals A1 and B.
1, C1 to switch the energization of each armature winding of the brushless motor 1 to control the rotation of the brushless motor 1, that is, to switch from synchronous operation to operation by position detection, while switching the on / off ratio (on time,
Off time).

As a result, the energization of each armature winding of the brushless motor 1 is switched to a predetermined value, and the applied voltage to each armature winding is varied, so that the brushless motor 1
The rotation speed of is controlled to a predetermined value.

[0007]

However, in the above brushless motor control method, in the case of the three-phase brushless motor 1, three position detection signals A1, B1, C1 are obtained from three terminal voltages U, V, W. Because
The circuit has a large number of parts, which is not only complicated but also costly.

Further, it is necessary to forcibly start the brushless motor 1 as a synchronous operation, and at the same time the applied voltage to each armature winding of the brushless motor 1 is increased to some extent. However, there is a problem in that when the operation is switched to the operation based on the position detection, the accuracy is low, and the rotation control at the time of the switching is not smooth. That is, the applied voltage to each armature winding during synchronous operation is somewhat high, whereas the applied voltage to each armature winding during operation based on position detection is the normal height as the target rotation speed. is there.

Further, when the brushless motor 1 is used as a motor of a compressor (of an air conditioner), the torque in one cycle (one rotation) is changed by a series of operations of suction, compression and discharge of the compressor. There is a problem that unevenness occurs and the rotation stability of the brushless motor 1 is poor.

The present invention has been made in view of the above problems, and an object thereof is to simplify a circuit for detecting the position of a rotor of a brushless motor, that is, to reduce the number of parts and reduce costs, and to perform synchronous operation. There is provided a brushless motor control method and device capable of smoothing the mode transition at the time of switching from the position detection to the operation based on the position detection and stabilizing the operation based on the position detection. Especially.

[0011]

In order to achieve the above object, the present invention provides a method for controlling a brushless motor, in which the brushless motor is operated synchronously and thereafter the operation is performed based on the position detection of the rotor of the brushless motor. In controlling the rotation of the brushless motor, at least one position detection signal is obtained based on the terminal voltages of a plurality of armature windings of the brushless motor, while the timings of the remaining position detection signals are obtained. Estimate based on the time between the edges of the position detection signal and the timing of the position detection signal, and switch the energization of the armature winding for a predetermined time after switching the brushless motor from synchronous operation to operation by rotor position detection. A timing switch that switches the energization of multiple armature windings of the same brushless motor based on the position detection signal immediately before execution. And a plurality of armature windings of the same brushless motor based on the position detection one cycle before or one rotation before of the brushless motor rotating at the estimated energization switching timing in the operation based on the position detection. The gist is that the timing of switching the energization of is estimated.

[0012]

With the above means, for example, in the case of a three-phase brushless motor, two or one position detection signal can be obtained based on the terminal voltage of each armature winding of the brushless motor (voltages different in phase by 120 degrees). To be The timing of the rising edge and the falling edge of this position detection signal is detected, the remaining edge of the position detection signal is estimated based on the measurement time between these timings, and the rising edge and the falling edge of the position detection signal are also estimated. The edges of the remaining position detection signals are estimated based on the measurement time between the edges and the next timing of the same position detection signal.

Further, until just before the brushless motor is switched from the synchronous operation to the operation based on the position detection, the position detection signal estimated based on the position detection signal immediately before is used to energize each armature winding of the brushless motor. Can be switched. As described above, since the position detection signal with a small phase delay is used, the mode transition from the synchronous operation to the operation based on the position detection becomes accurate.

After switching to the operation based on the position detection, each armature winding of the brushless motor is switched using the position detection signal estimated based on the position detection signal one cycle before (one rotation before). To be Therefore, when the torque due to the load of the brushless motor changes in one cycle (one rotation), the timing of the position detection signal corresponding to the torque pattern is obtained, and as a result, the operation of the brushless motor can be stabilized.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION A brushless motor control method and apparatus according to the present invention obtain at least one position detection signal based on terminal voltages of a plurality of armature windings of a DC brushless motor (hereinafter referred to as a brushless motor), and The timing of another position detection signal is estimated based on the obtained edge of the position detection signal.

Further, the brushless motor is switched from the synchronous operation to the operation based on the position detection. Until a predetermined time elapses from the operation switching, the timing of the position detection signal estimated during the synchronous operation (the energization switching of the armature winding is switched to. The position detection timing immediately before the brushless motor is used, and after the lapse of the predetermined time, the timing of the position detection signal estimated based on the position detection signal of one cycle before (one rotation before) the brushless motor is used. Switch the armature winding energization.

Therefore, the controller of the brushless motor of the present invention has, for example, the configuration shown in FIG. In addition,
In the figure, those parts that are the same as those corresponding parts in FIG. 9 are designated by the same reference numerals, and a description thereof will be omitted.

In FIG. 1, this control device inputs two terminal voltages (voltages having different phases of 120 degrees; induced voltages) U, V, W of the armature winding of the three-phase brushless motor 1 to detect two positions. A position detector 7 that outputs a signal (indicated by a solid line and a broken line in the figure) and a control circuit (microcomputer) 8 that estimates the timing of another position detection signal based on the two position detection signals are provided. There is.

Although the position detecting section 7 has a known circuit configuration, the number of components in the circuit configuration is reduced because only two position detection signals need to be obtained. The control circuit 8 also has the function of the control circuit 4 shown in FIG.

Next, the operation of the control device will be described with reference to the time charts of FIGS. 2 and 3 and the flow chart of FIG. 2 and 3, the signals corresponding to the signals shown in FIG. 10 are designated by the same reference numerals, and the description thereof will be omitted.

First, when the brushless motor 1 is started, the control circuit 8 outputs a control signal and a chopping signal for making the brushless motor 1 operate synchronously, and turns on and off a plurality of switch elements of the inverter unit 2 in a predetermined manner. I shall. As a result, the DC power supply Vcc is switched and applied to each armature winding of the brushless motor 1,
The energization of each armature winding is sequentially switched.

At this time, the terminal voltages U, V, W (for example, shown in FIGS. 2 (a) and 2 (c)) of each armature winding of the brushless motor 1 are input to the position detecting section 7. The position detection unit 7 outputs two position detection signals A2 and B2 by the same processing as in the conventional case (shown in FIGS. 2D and 2E).

During this synchronous operation, or when the predetermined time has not elapsed after the end of the synchronous operation (immediately before switching to the operation based on position detection), steps ST1 to S
Proceeding to T2, the rising edge (or falling edge) of the input position detection signal B2 is detected, and at the same time, the internal timer of the control circuit 8 is started.

Then, when the trailing edge (or leading edge) of the input position detection signal A2 is detected, step ST
From ST3 to ST4, as shown in FIG. 2, the time Tan (Ta1, Ta2) from the edge of the position detection signal B2 to the edge of the position detection signal A2 is measured in consideration of the time of the internal timer.

At the same time, that is, at the falling (or rising) edge of the position detection signal A2, the internal timer is started, and the measured predetermined time Ta1 (Ta
When 2) has elapsed (step ST5), for example, the time point a1 (arrow shown in FIG. 2 (f)) when the predetermined time Ta1 has elapsed can be estimated to be the rising edge of the remaining position detection signal C2 (step ST6). Then, the operations of steps ST1 to ST6 are repeated until the synchronous operation is switched to the operation based on the position detection and a predetermined time elapses (that is, until the operation mode is changed) (step ST).
7).

When a predetermined time has elapsed after the end of the synchronous operation (immediately after the end of the synchronous operation), the process proceeds from step ST7 to ST8, and the operation based on the position detection is performed from the synchronous operation. At this time, since the remaining position detection signal C2 indicated by the broken-line rectangular wave in FIG. 2 (f) is obtained based on the input position detection signals A2 and B2 by the above-described operation, the control circuit 8 detects the input position. The energization of each armature winding is switched based on the timings of the signals A2 and B2 and the estimated position detection signal C2.

Further, in step ST8, at the same time as the operation based on the position detection, the input position detection signal A2
When the falling edge (or rising edge) of is detected, the internal timer is started.

Then, when the falling edge (or rising edge) of the position detection signal B2 is detected (step ST9), the position detection is performed from the falling edge (or rising edge) of the position detection signal A2, taking into account the time of the internal timer. A predetermined time tbn (tb1, tb2; shown in FIG. 3 (e)) until the falling (or rising) of the signal B2 is measured, and the calculated time tbn is halved for a predetermined time. tb1 / 2 (or tb2
/ 2) is calculated (step ST10).

Then, when the falling edge of the position detection signal A2 is detected (step ST15), the internal timer is started (step ST11).

Subsequently, the calculated predetermined time tb1 /
When 2 has elapsed (step ST13), this predetermined time t
Time point b1 when b1 / 2 has elapsed (arrow shown in FIG. 3 (f))
Can be estimated as the rising edge of the remaining position detection signal C2 (step ST14).

By repeating the operations of steps ST8 to ST14, the remaining position detection signal C2 (shown by the broken line waveform in FIG. 3 (f)) can be obtained based on the input position detection signals A2 and B2.

After the synchronous operation is switched to the operation based on the position detection, the steps ST8 to S are executed.
By repeating the operation of T14, the control circuit 8 outputs a control signal for switching the energization of each armature winding at the timing of the input position detection signals A2, B2 and the obtained position detection signal C2.

In this case, as described in the above step, the remaining position detection signal C2 (shown by the broken line waveform in FIG. 3 (f)) is obtained based on the input position detection signals A2 and B2. In the control circuit 8, the energization of each armature winding can be switched according to the timing of the input position detection signals A2 and B2 and the estimated position detection signal C2.

As described above, when the synchronous operation of the brushless motor 1 is switched to the operation based on the position detection, that is, when the operation mode is changed, the other is detected based on the position detection signals A2 and B2 having a small phase shift immediately before the operation switching. The timing of the position detection signal C2 is estimated. Further, after the operation mode is changed, the position detection signals A2 and B one cycle before are output.
The timing of the position detection signal C2 is estimated based on 2.

Therefore, since only two position detection signals can be obtained based on the terminal voltages U, V, W of the armature windings of the brushless motor 1, the number of circuit components of the position detecting section 7 can be reduced. In addition, the number of lines of the position detection signal becomes smaller.

Further, the mode can be accurately changed, and after the operation mode is changed, a position detection signal corresponding to the load torque of the brushless motor 1 is obtained, so that stable operation can be performed. . For example, even when the brushless motor 1 is used as a compressor motor of an air conditioner, the torque pattern is the same every cycle (and one rotation) due to a series of operations of suction, compression, and discharge, and one cycle before Since the remaining one position detection signal is estimated based on the position detection signal, the driving can be stabilized.

The position detection signal C2 immediately after switching to the operation based on the position detection shown in FIG. 2 and FIG.
The timing of is estimated, for example, by the method immediately before the same operation.

Time charts of FIGS. 5 and 6 and FIG.
And the flow chart of FIG. 8 is for explaining another embodiment of the present invention. For the controller of the brushless motor in this embodiment, refer to FIG. In addition, in FIGS. 5 and 6, signals corresponding to the signals shown in FIGS. 2 and 3 are denoted by the same reference numerals, and description thereof will be omitted.

First, when the brushless motor 1 is started, the control circuit 8 outputs a control signal and a chopping signal for making the brushless motor 1 operate synchronously, and turns on and off a plurality of switching elements of the inverter unit 2 in a predetermined manner. I shall. As a result, the DC power supply Vcc is switched and applied to each armature winding of the brushless motor 1,
The energization of each armature winding is sequentially switched.

At this time, the terminal voltages U, V, W (for example, shown in FIGS. 5A and 5C) of each armature winding of the brushless motor 1 are input to the position detecting section 7. The position detector 7 outputs one position detection signal A2 by the same process as the conventional one (solid line in FIG. 1; shown in FIG. 5D).

During this synchronous operation, or when the predetermined time has not elapsed since the end of the synchronous operation (immediately before switching to the operation based on position detection), the process proceeds from step ST20 to ST21, and the input position detection signal A2 At the same time when the rising (or the falling) is detected, the internal timer of the control circuit 8 is started.

Subsequently, when the trailing edge (or leading edge) of the input position detection signal A2 is detected, step ST
From ST22 to ST23, as shown in FIG. 5D, the time Tcn (Tc1, Ta2) from the edge of the position detection signal A2 to the edge of the position detection signal A2 is measured by taking the time of the internal timer into consideration. To do.

The above measured time Tc1 (or Tc
2) Tc1 / 3 and 2Tc1 / 3 based on 2)
(Alternatively, Tc2 / 3 and 2Tc2 / 3) are calculated (step ST24).

Next, the calculated predetermined time T from the fall (or rise) of the position detection signal A2.
When c1 / 3 (Tc2 / 3) has elapsed (step ST2
5), for example, time point c1 when a predetermined time Tc1 / 3 has passed
The arrow (shown in FIG. 5 (f)) is set as the rising edge of the position detection signal C2 (step ST26).

Subsequently, if the synchronous operation is not switched to the operation based on the position detection, that is, the operation mode is not switched (step ST27), and the predetermined time has not elapsed from the switching of the operation (step ST28), the position is determined. When the calculated predetermined time 2Tc1 / 3 (2Tc2 / 3) has elapsed from the fall (or rise) of the detection signal A2 (step ST29), for example, the predetermined time 2T
Time point d1 when c1 / 3 has elapsed (arrow shown in FIG. 5 (f))
Is the rising edge of the position detection signal B2 (step ST30).

Next, the brushless motor 1 detects the position from the synchronous operation unless the synchronous operation is switched to the operation based on the position detection, that is, the operation mode is not switched and a predetermined time has not elapsed from the switching of the operation. The operation of steps ST20 to ST30 is repeated until the operation is switched to the operation based on (that is, the operation mode is switched) (steps ST31 and ST32).

When a predetermined time has elapsed after the end of the synchronous operation (immediately after the end of the synchronous operation), step ST32
To ST33, the synchronous operation is switched to the operation based on the position detection. At this time, the position detection signals B2 and C2 are generated based on the input position detection signal A2 by the above-described operation.
(As shown in FIGS. 5 (e) and 5 (f)),
In the control circuit 8, the energization of each armature winding can be switched according to the timing of the input position detection signal A2 and the estimated position detection signals B2 and C2.

Further, in step ST33, when the falling edge (or rising edge) of the input position detection signal A2 is detected at the same time when the operation is switched, the internal timer is started.

When the falling edge (or rising edge) of the position detection signal A2 is detected (step ST34), the position detection signal A2 is detected from the falling edge (or rising edge) in consideration of the time of the internal timer. A predetermined time tdn (td1, td2; shown in FIG. 6D) until the rise (or fall) of A2 is measured (step ST35).

Then, the measured time tdn is 1 /
The calculation of 3, 2/3 is executed, and the predetermined time tb1 / 3,
2tb2 / 3 (or tb2 / 3, 2tb2 / 3) is calculated (step ST36).

Then, when the next falling edge (or rising edge) of the position detection signal A2 is detected (step ST37), the predetermined time tb1 / 3, 2tb2 is reached.
An internal timer of / 3 (or tb2 / 3, 2tb2 / 3) is started (step ST38).

Subsequently, the calculated predetermined time td1 /
When 3 has elapsed (step ST39), this predetermined time t
Time point e1 when d1 / 3 has elapsed (arrow shown in FIG. 6 (f))
Is the rising edge of the remaining position detection signal C2 (step ST40).

Subsequently, the calculated predetermined time 2td1
When / 3 has passed (step ST41), the time point f1 (arrow shown in FIG. 6 (f)) when the predetermined time 2td1 / 3 has passed is set as the falling edge of the remaining position detection signal B2 (step ST42).

By repeating the operation of steps ST33 to ST42, the remaining position detection signals B2, C2 (FIG. 6 (e), based on the input position detection signal A2) are obtained.
(Shown by the broken line waveform in (f)) can be obtained.

After switching from the synchronous operation to the operation based on the position detection, the control circuit 8 repeats the operations of the steps ST33 to ST42 so that the input position detection signal A2 and the obtained position detection signals B2 and C3 are detected. A control signal for switching the energization of each armature winding according to the timing is output.

In this case, as described in the above step, the remaining position detection signal C2 (shown by the broken line waveform in FIG. 3 (f)) is obtained based on the input position detection signals A2 and B2. In the control circuit 8, the energization of each armature winding can be switched according to the timing of the input position detection signals A2 and B2 and the estimated position detection signal C2.

As described above, when the synchronous operation of the brushless motor 1 is switched to the operation based on the position detection, that is, when the operation mode is changed, another position is detected based on the position detection signal A2 having a small phase shift immediately before the operation switching. Detection signal B
2, the timing of C2 is estimated. Further, after the operation mode is changed, the timings of the position detection signals B2 and C2 are estimated based on the position detection signal A2 one cycle before.

Therefore, as in the previous embodiment, since only one position detection signal is obtained based on the terminal voltages U, V, W of the armature windings of the brushless motor 1, position detection is performed more than in the previous embodiment. Not only the number of circuit components of the section 7 is reduced, but also the number of lines of the position detection signal is reduced.

Further, the mode can be accurately changed, and after the operation mode is changed, a position detection signal corresponding to the load torque of the brushless motor 1 is obtained, so that stable operation can be performed. . For example, even when the brushless motor 1 is used as a compressor motor of an air conditioner, the torque pattern is the same for each cycle (1 rotation) due to a series of operations of suction, compression and discharge, and the position of the position one cycle before Since the remaining two position detection signals are estimated based on the detection signals, the driving can be stabilized. The timing of the position detection signal C2 immediately after switching to the operation based on the position detection shown in FIGS. 5 and 6 is estimated by, for example, a method immediately before the same operation.

[0060]

As described above, according to the present invention, at least one position detection signal is obtained based on the terminal voltages of the plurality of armature windings of the brushless motor, and the obtained position detection signal is detected. The timing of other position detection signals is estimated based on the edges, and the brushless motor is started in synchronous operation, and then the operation is switched to operation based on rotor position detection, and the same synchronous operation is performed until a predetermined time elapses. Each time the position of the brushless motor is estimated by using the timing of the position detection signal that is estimated from time to time and the timing of the position detection signal that is estimated based on the position detection signal of one cycle before or one rotation of the brushless motor after the predetermined time has elapsed. By switching the energization of the armature winding, the circuit for detecting the position of the brushless motor rotor can be simplified. It is possible to reduce the cost and reduce the cost, to smooth the mode transition when switching from synchronous operation to operation based on position detection, and to stabilize operation based on position detection. There is a useful effect that you can.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a controller to which a rotor position detecting method for a brushless motor 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 time chart diagram for explaining 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.

FIG. 5 is a schematic time chart diagram for explaining another embodiment of the present invention.

FIG. 6 is a schematic time chart diagram for explaining another embodiment of the present invention.

FIG. 7 is a schematic flowchart illustrating another embodiment of the present invention.

FIG. 8 is a schematic flow chart illustrating another embodiment of the present invention.

FIG. 9 is a schematic block diagram of a conventional controller for a brushless motor.

FIG. 10 is a schematic time chart diagram for explaining the operation of the control device shown in FIG.

[Explanation of symbols]

 1 Brushless Motor (DC Brushless Motor) 1a Rotor (of Brushless Motor 1) 2 Inverter Section 3,7 Position Detection Section 4,8 Control Circuit (Microcomputer) 5 Chopping Section 6 Driver Section a Spike Voltage U, V, W Electric Terminal voltage of child winding A1, B1, C1, A2, B2, C2 Position detection signal

Claims (4)

[Claims] 1. A brushless motor control method in which a brushless motor is operated synchronously, and thereafter, operation is performed based on position detection of a rotor of the brushless motor, wherein a plurality of brushless motors are used when rotationally controlling the brushless motor. While obtaining at least one position detection signal based on the terminal voltage of the armature winding, the timing of the remaining position detection signal is set to the time between the edges of the obtained position detection signal and the timing of the same position detection signal. Based on the position detection signal immediately before switching the energization of the armature winding, a plurality of brushless motors of the brushless motor are estimated based on the position detection signal for a predetermined time after switching from the synchronous operation of the brushless motor to the operation of detecting the rotor position. Estimate the timing of switching the energization of the armature winding, and in the operation based on the position detection, the estimation is performed. The timing for switching the energization of a plurality of brushless armature windings is estimated based on the position detection of the brushless motor rotating one cycle before or one rotation before according to the energization switching timing. Brushless motor control method. 2. A controller for a brushless motor, in which the brushless motor is operated synchronously and thereafter is operated based on the position detection of the rotor of the brushless motor, wherein terminal voltages of a plurality of armature windings of the brushless motor are applied. Position detection means for obtaining at least one position detection signal based on the position detection signal, and the timing of the remaining position detection signal based on the position detection signal, the time between the edges of the obtained position detection signal and the timing of the position detection signal Based on the position detection signal immediately before switching the energization of the armature winding, a plurality of armatures of the brushless motor are estimated from the end of the synchronous operation of the brushless motor until a predetermined time elapses. While inferring the timing of switching the energization of the winding, in the operation based on the position detection after the elapse of the predetermined time, the inference Estimating means for estimating the timing of switching the energization of a plurality of armature windings of the brushless motor based on the position detection of the brushless motor rotating one cycle before or one rotation before according to the energization switching timing. From a position detection operation to a predetermined time period and after the predetermined time period has elapsed, the control means controls the rotation of the brushless motor at the energization switching timing estimated based on the at least one position detection signal. A brushless motor control device. 3. A three-phase brushless motor is synchronously operated,
Then, in the control method of the brushless motor, which is operated based on the position detection of the rotor of the brushless motor, two position detection signals are obtained based on the terminal voltages of the three armature windings of the brushless motor, and at least the above When switching the brushless motor from synchronous operation to operation based on rotor position detection, from the rising edge (or falling edge) of the obtained one position detection signal to the falling edge (or rising edge) of the other position detection signal. The rise (or fall) of the remaining position detection signal is estimated based on the time and the fall (or rise) timing of the other position detection signal, and position detection is performed at least after a lapse of a predetermined time from the end of the synchronous operation. In the operation based on the fall of the other position detection signal ( Based on the time from the rising edge) to the falling edge (or rising edge) of one position detection signal and the timing of the falling edge (or rising edge) of the other position detection signal after one cycle, the remaining rising edge of the position detection signal (or (Falling) is estimated, and energization of each armature winding of the brushless motor is switched based on the estimated position detection signal and the obtained position detection signal. Motor control method. 4. A control method for a brushless motor, wherein a three-phase brushless motor is operated synchronously, and thereafter, operation is performed based on position detection of a rotor of the brushless motor, wherein three armature windings of the brushless motor are controlled. When one position detection signal is obtained based on the terminal voltage and at least the brushless motor is switched from the synchronous operation to the operation based on the rotor position detection, the same operation is performed from the rising (or the falling) of the obtained position detection signal. The time until the fall (or rise) of the position detection signal is detected, and 1/3 and 2/3 of the detected time are detected.
From the obtained position detection signal falling edge (rising edge) to the rising edge (or falling edge) of the remaining one position detection signal at the time point of 1/3 of the calculated time. The time lapse of the calculated 2/3 from the falling edge (rising edge) of the detection signal is used as the falling edge (or rising edge) of the other position detection signal, and at least the position is detected after a lapse of a predetermined time from the end of the synchronous operation. In the operation based on the above, the time from the fall (or rise) of the obtained position detection signal to the rise (or fall) of the same position detection signal is detected, and 1/3 of the detected time is detected. And ⅔ are calculated, and the calculated ⅓ from the falling edge (rising edge) of the position detection signal after one cycle.
Of the remaining position detection signal from the obtained position detection signal falling (rising) to the other position of the other position. The fall (or rise) of the detection signal is used, and the energization of each armature winding of the brushless motor is switched according to the obtained position detection signal and the obtained position detection signal. Control method.