JPH08111995A - Method and device for controlling brushless motor - Google Patents

Abstract

PURPOSE: To always maintain the operating efficiency of a brushless motor at the highest level and, in its turn, to reduce the power consumption of the motor. CONSTITUTION: At the time of controlling the rotation of a brushless motor 1 by detecting the position of the rotor 1a of the motor 1 and switching the currents of a plurality of armature windings based on the detecting timing of the position, a position detecting section 3 detects the neutral point of the terminal voltage (induced voltage) of each armature winding based on the induced voltage of each winding and a control circuit 7 obtains the phase differences from the neutral points to a point (position detecting timing) which is delayed in phase by a prescribed phase by using the data stored in a ROM 7a and, at the same time, switches the current of each armature winding at the timing obtained from the phase differences. The ROM 7a stores the data from which the optimum winding current switching timing at which the operating efficiency of the motor 1 can be raised to the highest level at every number of rotation can be obtained.

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 that can always maintain the maximum operating efficiency during operation by detecting the rotor position.

[0002]

2. Description of the Related Art In order to control the rotation of this DC brushless motor (hereinafter referred to as a brushless motor), for example, in the case of a three-phase brushless motor, a control device shown in FIG. 13 is conventionally required.

In FIG. 1, 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 an armature winding of a brushless motor 1. Terminal voltage of the brushless motor 1 (for example, voltages having a phase difference of 120 degrees; induced voltage) R,
A position detection unit 3 for detecting the position of the rotor 1a based on S and T, and a predetermined switching of each armature winding current of the brushless motor 1, and a position detection signal A from the position detection unit 3.
Based on B and C, a control signal of the inverter unit 2 is output to switch each armature winding current to a predetermined value, while a chopping signal for chopping the predetermined control signal at a predetermined frequency among the control signals is output. A control circuit (microcomputer) 4, a chopping unit 5 for chopping and outputting the control signal, and a control signal including the chopped signal causes switching means (transistor; Tr) U, V, W of the inverter unit 2. A driver unit 6 for driving X, Y, and Z is provided.

In the controller having the above structure, when the brushless motor 1 is started, the brushless motor 1 is operated in synchronization for a predetermined time, but after the predetermined time has elapsed, the brushless motor 1 is operated based on the position detection signal of the rotor 1a of the brushless motor 1. The brushless motor 1 is rotationally controlled (switched to so-called position detection operation).

In the operation by the above position detection, the position of the rotor 1a is detected, and each armature winding current is switched based on this position detection. The switching timing is the induced voltage generated in each armature winding. It is common to set the point at which the phase is delayed 30 degrees or 90 degrees from the neutral point potential.

Therefore, the position detector 3 divides the terminal voltages R, S and T of the armature windings shown in FIGS. 14A, 14B and 14C by the voltage dividing circuit 3a, These divided voltages are smoothed by the differentiating circuit 3b and the integrating circuit 3c, and the phase angle is delayed by 90 degrees (FIG. 14 (d),
(Shown in (e) and (f)). Further, the signals with a phase angle delay of 90 degrees are compared with a predetermined reference voltage (neutral point voltage; Vn) by a comparator circuit 3d by each comparator to obtain position detection signals A, B, C (FIG. 14 (g), (Shown in (h) and (i)). The reference voltage Vn can be obtained by combining the output of the integrating circuit 3c with the resistance circuit 3e.

The control circuit 4 which receives the position detection signals A, B and C detects the position of the rotor 1a and switches the armature winding current based on the timing of each position detection. And outputs a control signal for turning on and off each switching element. This control signal is shown in FIG.
4 (j) to (o) are upper arm signals and lower arm signals, and the upper arm signals turn on / off the transistors U, V, W forming the upper arm of the inverter unit 2,
The lower arm signal turns on and off the transistors X, Y, and Z that form the lower arm of the inverter unit 2.

The control circuit 4 also outputs a chopping signal for chopping the upper arm signal to the chopping unit 5, for example.
, And the chopping unit 5 chops the L level of the upper arm signal (shown in (q), (r), and (s) of FIG. 14).

As described above, the armature winding currents of the brushless motor 1 are switched based on the position detection signals A, B, C to control the rotation of the brushless motor 1, and the on / off ratio (on time, on time, By changing the off time), the rotation speed of the brushless motor 1 is controlled to a predetermined value.

[0010]

In the above brushless motor control method, each terminal voltage (induced voltage) R,
The position detection unit 3 detects the chopping waveform included in S and T.
The position detection signal of the rotor 1a is obtained by smoothing the voltage obtained by smoothing the chopping waveform and integrating the voltage obtained by smoothing the chopping waveform. Therefore, the position of the rotor 1a can be detected easily. Becomes

However, the terminal voltages R, S and T of the armature windings are not limited to the frequency components of the chopping signal, but various frequency components such as the frequency component of the rotation speed and the frequency component of the waveform of the induced voltage (sine wave). Ingredients) etc. are included. Therefore, when the terminal voltages R, S, and T are passed through the integral filter of the position detector 3 to obtain the position detection signals A, B, and C, the rotation speed of the brushless motor 1 changes due to the characteristics of the integral filter. Accordingly, the output of the position detector 3 does not delay the phase angle by 90 degrees with respect to the neutral point potential of the induced voltage, that is, an error occurs in the phase difference of 90 degrees.

Therefore, when it is necessary to control the brushless motor 1 over a wide range of rotation speeds, the phase angle 90 degree delay greatly differs depending on each rotation speed, that is, the phase angle 90 degree error increases, resulting in Not only an error occurs in the position detection of the rotor 1a, but the error becomes large,
As a result, there is a problem that the operating efficiency of the brushless motor 1 is deteriorated.

Further, the phase difference that maximizes the operating efficiency of the brushless motor 1 (a predetermined phase delay from the neutral point of the induced voltage)
However, it may not necessarily be said to be 90 degrees depending on each rotation speed and load condition. Therefore, when position detection is performed based on the output position detection signals A, B, C of the position detection unit 3 and each armature winding current is switched at the timing of this position detection, the operating efficiency of the brushless motor 1 is always the maximum. However, there is a drawback that the power consumption of the brushless motor 1 is increased.

The present invention has been made in view of the above problems, and an object thereof is to be independent of the rotation speed of a brushless motor,
Another object of the present invention is to provide a brushless motor control method and an apparatus thereof, which can always maximize the operation of the brushless motor regardless of the load state, and thus can reduce power consumption.

[0015]

In order to achieve the above object, a brushless motor control method and apparatus according to the present invention detect the position of a rotor of a brushless motor, and the brushless motor is detected at the position detection timing. Of the armature winding of the brushless motor detects the neutral point potential of the induced voltage when controlling the rotation of the brushless motor by switching a plurality of armature winding currents (winding currents) Then, the rotation speed of the brushless motor is detected by the detected neutral point, and at the phase angle at which the operation efficiency of the brushless motor is maximized from the timing of the neutral point potential according to at least the detected rotation speed. The gist is that the winding current is switched.

[0016]

Data for delaying the timing of the neutral point potential by a predetermined phase angle to obtain the switching timing of the winding current is stored in advance in the storage means, and the storage means stores at least each rotation of the brushless motor. Data is stored for each number so that the armature winding current can be switched so that the operating efficiency of the brushless motor is maximized.

When the brushless motor is rotationally controlled based on the position detection of the rotor, the neutral point potential of the induced voltage is detected by the terminal voltage of each armature winding of the brushless motor, and the timing of this neutral point potential. And the rotation speed of the brushless motor is detected by the timing of position detection. Then, data corresponding to the detected rotational speed is read from the storage means, and the position detection timing obtained by delaying the timing of the neutral point potential by a predetermined phase angle is corrected by this data.

The position detection timing of the rotor is obtained from the data of the storage means, and the armature winding currents of the brushless motor are switched based on these position detection timings, so that the operating efficiency of the brushless motor is always maximized. Become.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A brushless motor control method and apparatus according to the present invention detect the position of a rotor of a DC brushless motor (hereinafter referred to as a brushless motor) and, based on the position detection timing, a plurality of armature winding currents are detected. When switching, the neutral point of the induced voltage is detected by the terminal voltage (induced voltage) of each armature winding, and the point (position detection timing) delayed by a predetermined phase (for example, 30 degrees or 90 degrees) from the neutral point. Up to the phase difference obtained by using the ROM data, the rotor position detection timing is obtained based on the obtained phase difference, and the armature winding current is switched based on the position detection timing. The ROM stores in advance data necessary for switching each armature winding current (winding current) so as to maximize the operating efficiency of the brushless motor for each rotation speed.

Therefore, the controller of the brushless motor of the present invention has, for example, the configuration shown in FIG. Note that, in the figure, the same parts as those in FIG.

In FIG. 1, this control device inputs the position detection signals A, B, C from the position detection unit 3 to determine the switching timing of the winding current, and uses the data of the ROM 7a to detect the position. A control circuit that corrects the phases of the signals A, B, and C to obtain the switching timing of the winding current, and outputs the control signal of the inverter unit 2 for switching the plurality of armature winding currents of the brushless motor 1 at this timing. A (microcomputer) 7 is provided.

The control circuit 7 has, in addition to the function of the control circuit 4 shown in FIG. 12, a ROM 7a, a first timer section 7b, an arithmetic section 7c, a second timer section 7d, an applied voltage output section 7f and a drive signal switching. It has a part 7e. Further, the ROM 7a is data obtained in advance in accordance with the total number of rotations required for the rotation control of the brushless motor 1 and data necessary for obtaining the switching timing of the winding current that maximizes the operation efficiency for each number of rotations. Yes, this data is stored in the form of the table shown in Table 1 below.

[0023]

[Table 1] Note that f shown in Table 1 above is the rotation speed of the brushless motor 1, and θ (η) is data of the phase difference from the neutral point potential of the induced voltage that maximizes the operating efficiency of the brushless motor 1, and θ
(X) is data of the actual phase difference at each rotation speed. The data θ (η) and θ (x) are obtained, for example, by actually controlling the rotation of the brushless motor 1.

Next, the operation of the control device will be described with reference to the time chart of FIG. 2 and the flow chart of FIG. 2 and 3, the signals corresponding to the signals shown in FIG. 10 are denoted by the same reference numerals and will not be described repeatedly.

First, for example, in order to operate the three-phase brushless motor 1 by position detection, that is, in steady operation, the control circuit 7 outputs a control signal and a chopping signal to output a plurality of transistors U, V, W of the inverter section 2. , X,
Turn Y and Z on and off as desired. As a result, the DC power supply Vcc is switched and applied to each armature winding of the brushless motor 1, and the current of each armature winding is sequentially switched to control the rotation of the brushless motor 1.

At this time, the position detecting unit 3 causes the terminal voltages (induced voltages) U, V, of the armature windings of the brushless motor 1 to be detected.
W is input (shown in FIGS. 2 (a) and 2 (c)), and the position detection unit 3 has three position detection signals A, B, C as in the conventional case.
Is output (shown in FIGS. 2D, 2E, and 2F).

As described in the conventional example, the position detection signals A, B, and C from the position detection unit 3 corresponding to the rotation speed of the brushless motor 1 have a phase angle of 90 degrees (or 30) from the neutral point potential of the induced voltage. Delay), that is, the phase difference does not become 90 degrees depending on the rotation speed. Further, even if the phase difference is 90 degrees, the operating efficiency of the brushless motor 1 is not always the maximum. For example, in FIG.
As shown in (e) and (f), a value θ smaller than the phase difference θ (η) that maximizes the operation efficiency of the brushless motor 1.
(X), that is, the position detection timing is advanced by θ (η) −θ (x). As a result, the upper arm signal and the lower arm signal for driving the transistors U, V, W, X, Y, and Z of the inverter unit 2 become the timings shown by the broken lines in FIGS. Operational efficiency of 1 is not maximum.

Therefore, when the control circuit 7 receives the input position detection signals A, B and C, the control circuit 7 proceeds from step ST1 to ST2 and determines the time between the rising and falling of the position detection signals A, B and C by the first timer. The rotation speed f of the brushless motor 1 is calculated by measurement using the section 7b.

Then, the position detection timing for switching each armature winding current is obtained based on the calculated rotation speed f (and the predetermined condition) (step ST3). For example, when the rotation speed f of the brushless motor 1 is 30 Hz (phase difference θ (x) = 80 degrees), the phase difference θ (η)
Is 85 degrees, the operation unit 7c of the control unit 7 determines that the measurement time of the first timer unit 7b and the ROM 7
The data θ (η) corresponding to the rotation speed f is read from a, and the phase error θ (η) − is obtained based on the data θ (η).
θ (x) (= θ (n)) is calculated. Further, the time corresponding to this phase error θ (n) (= 85 degrees−80 degrees = 5 degrees) is calculated and set in the second timer section 7d.

When the time measured by the second timer section 7d has elapsed, it is determined that it is the position detection timing of the rotor 1a, and the drive signal switching section 7e is a control signal for switching the armature winding current. Arm signal and lower arm signal (shown by solid lines in FIGS. 2 (g) to (l))
Is output to the chopping unit 5 (step ST4).

That is, the rising and falling timings of the input position detection signals A, B and C are determined by the second timer section 7.
The correction is performed only for the time set in d, that is, the switching timing of the winding current obtained based on the input position detection signals A, B, C is corrected to the point where the operation of the brushless motor 1 is maximized.

On the other hand, the arithmetic unit 7c outputs the applied voltage determined by the calculated rotational speed f and the input rotational speed command to the applied voltage output unit 7f. In the applied voltage output unit 7f, each electric machine is driven. A chopping signal having a predetermined duty ratio is output to the chopping unit 5 in order to set the applied voltage of the child winding to the determined value.

Similarly, the ROM for the input position detection signals A, B, and C is provided for each rotation speed f of the brushless motor 1.
The table of 7a is referred to, and the phase error θ (η) −θ
(X) is corrected, and each armature winding current is switched according to the corrected position detection timing. In addition, the above-mentioned processing is performed every time the input position detection signals A, B, C are input.
Or it is repeatedly executed every time it changes.

In the above embodiment, the brushless motor 1
The phase error θ (η) −θ (x) is calculated for each number of rotations of, but θ (n) (= θ (η) −θ) of the calculation result is calculated.
Only (x)) is used as the table shown in Table 2 below.
If it is stored in M7a, the calculation process can be omitted.

[0035]

[Table 2] Further, in the above embodiment, each armature winding current is switched later than the timing of the input position detection signals A, B and C. However, depending on the load state (usage condition) of the brushless motor 1, the input position may be changed. The operating efficiency may not be maximized unless the armature winding current is switched earlier than the timing of the detection signals A, B, and C. In this case, the time when the position detection signal next to the input position detection signals A, B, C is detected is predicted, the time of the phase error θ (n) is subtracted from this time, and the time is set in the second timer unit 7d. Then, the switching timing of the next armature winding current may be corrected.

By the way, as the correction of the above-mentioned phase angle, that is, the correction of the switching timing of the armature winding current,
The operating efficiency may be maximized by changing the switching timing of each armature winding current according to the load condition of the brushless motor 1 as well as the rotation speed f.

For that purpose, it is necessary to detect the load state of the brushless motor 1. For example, when the brushless motor 1 is used in a compressor or the like, a pressure sensor 8 and a temperature sensor 9 are used as shown in FIG. To detect the discharge pressure and temperature of the compressor, and to detect the suction pressure and temperature of the compressor using the pressure sensor 10 and the temperature sensor 11, and determine the load state based on these detected pressure and temperature.

Since the cost of the pressure sensors 8 and 9 and the temperature sensors 10 and 11 is high, the load applied by the voltage applied to the armature winding of the brushless motor 1 (voltage in the inverter section 2). You may make it determine a state. In this case, since the voltage is determined by the duty cycle of the chopping signal, the load state can be estimated by the control circuit 7, and it is not necessary to add a component such as a voltage sensor.

The conditions for judging the above load state are as follows:
It is possible to use at least one of the discharge pressure, the discharge temperature, the suction pressure, the suction temperature, and the voltage described above.

Therefore, in the ROM 7a of the control circuit 7, data that maximizes the operating efficiency is stored in the form of a table shown in the following Table 3 in consideration of the rotation speed f and a predetermined condition (load condition determination condition). .

[0041]

[Table 3] In Table 3 above, the phase error θ for each rotation speed fn
Not only is (nn) different, this phase error θ (nn) is also different, for example, for duty cycle (voltage Vn). For example, when the rotation speed is f1 and the voltage applied to the armature winding is V1, the input position detection signals A, B,
The phase error θ (11) in Table 2 is corrected for C.

Then, as in the previous embodiment, the arithmetic unit 7c calculates the time corresponding to the phase error θ (11) read from the R0M 7a and sets it in the second timer unit 7d. When the time measured by the second timer unit 7d reaches the time corresponding to the phase error θ (11), it is determined that it is the position detection timing of the rotor 1a, and the drive signal switching unit 7e determines the armature winding current. Control signals (upper arm signal and lower arm signal) for switching are output to the chopping unit 5 (shown by solid lines in FIGS. 2G to 2L).

In this way, the input position detection signal is corrected, the winding current switching timing is obtained based on the corrected position detection signal, and the armature is switched by the winding current switching timing. A control signal for switching the winding current is output.

Similarly, the input position detection signals A, B,
By performing the phase correction on C, the operating efficiency of the brushless motor 1 is always maximized regardless of the rotation speed f and the load state.

As in the previous embodiment, depending on the usage of the brushless motor 1, each armature winding current must be switched earlier than the timing of the input position detection signal.
It may not be the maximum efficiency. In this case, the above-described correction may be performed when the armature winding current is switched next time, not when the current armature winding current is switched.

In this way, the input position detection signals A, B, C
Is phase-corrected using the table of Table 1 or Table 2 or Table 3, and the corrected position detection signals A, B, C
The switching timing of the winding current is obtained based on the above, that is, the optimal switching timing of the winding current that maximizes the operation efficiency is obtained.

Therefore, the input position detection signals A, B, C
Whatever the phase angle with respect to the neutral point potential of the induced voltage, the operating efficiency of the brushless motor 1 can always be maximized, and regardless of the rotation speed f or the load state of the brushless motor 1, The operation efficiency can be maximized, and eventually the power consumption can be reduced.

FIG. 4 is a block diagram of a controller for a brushless motor showing a second embodiment of the present invention, FIG. 5 is a time chart for explaining the operation of the controller, and FIG. 6 is an operation of the controller. It is a flowchart figure explaining. In FIG. 4, the same parts as those in FIG.

In the second embodiment, the neutral point potential of the induced voltage is detected by the terminal voltage (induced voltage) of the one-phase armature winding of the brushless motor 1 without using the integral filter, and the operation is performed. The position detection timings of all phases are calculated based on the timing of the one neutral point potential so that the efficiency is maximized, and the armature winding currents are switched according to these position detection timings.

Therefore, as shown in FIG. 4, this brushless motor controller divides a terminal voltage (induced voltage) R of one of the armature windings of the three-phase brushless motor 1 into a predetermined voltage. Voltage dividing circuit 12a and DC power supply V
Resistor circuit 12b for obtaining a predetermined reference voltage Va from cc
And a comparison circuit 12c which compares the terminal voltage R with a predetermined reference voltage Va and outputs a signal including information on the neutral point potential of the induced voltage. The voltage dividing circuit 12a and the resistance circuit 12 are provided.
b and the comparison circuit 12c
The position signal R0 from 2 is input to the control circuit (microcomputer) 13. The voltage division ratio of the voltage dividing circuit 12a and the resistance ratio of the resistance circuit 12b are set so that the neutral point potential of the induced voltage can be detected.

Since the position signal R0 from the position detector 12 is a signal with no phase delay, the control circuit 13 operates as shown in FIG.
In addition to the function of the control circuit 7 shown in FIG. 3, the ROM 13a stores data (table shown in Table 4 below) necessary for delaying the position signal R0 by a predetermined phase for each rotation speed f, and the predetermined value. It has a function of obtaining the position detection timing of the rotor 1a based on the phase delay signal.

[0052]

[Table 4] The data in the table shown in Table 4 above is phase angle data calculated in advance in order to switch each armature winding current so as to maximize the operation efficiency for each frequency.

Further, the first timer unit 13 of the control circuit 13
b, the operation unit 13c, the second timer unit 13d, the drive signal switching unit 13e, and the applied voltage output 13f are the first ones shown in FIG.
Corresponding to the timer unit 7b, the arithmetic unit 7c, the second timer unit 7d, the drive signal switching unit 7e, and the applied voltage output 7f, and have the same functions.

Next, the operation of the controller for the brushless motor having the above structure will be described in detail with reference to the time chart of FIG. 5 and the flowchart of FIG. 6. First, as in the previous embodiment, the control circuit 13 causes the brushless motor 1 to operate. Is assumed to be a steady operation.

At this time, the terminal voltage for one phase (induced voltage)
R is input to the position detection unit 12, and the position detection unit 1
The second voltage dividing circuit 12a divides the terminal voltage R by a resistor (shown in FIG. 5B). The comparison circuit 12c of the position detection unit 12 compares the voltage Ru obtained by the voltage division with a predetermined reference voltage Va, and a voltage waveform equal to or higher than the predetermined reference voltage Va, that is, a voltage including the neutral point potential information of the induced voltage. The waveform is output to the control circuit 13 (shown in FIG. 5C).

On the other hand, the control circuit 13 outputs a control signal and a chopping signal for turning on / off the transistors U, V, W, X, Y, and Z of the inverter unit 2 in a predetermined manner, and each armature winding current. Switch. At this time, the first rising edge or the first falling edge of the position signal R0 from the position detection unit 12 after these switching timings are detected, and the timing of this edge is determined to be the timing of the neutral point potential of the induced voltage. .

For example, after the switching timing of the armature winding current of arrow a (or arrow b) shown in FIG. 5A, the first falling edges Ta and Tb are set to the neutral point potential of the induced voltage. It can be judged as timing.
Further, after the switching timing of the armature winding current of arrow c (or arrow d) shown in FIG. 5A, the first rising edges Tc and Td are determined as the timing of the neutral point potential of the induced voltage. be able to. That is, a spike voltage is always generated by switching each armature winding current, and there is a neutral point potential of the induced voltage after the spike voltage.

Therefore, when the control circuit 13 receives the position signal R0 from the position detection unit 12, the second timer unit 13d receives the position signal R0.
(Step ST10), for example, as shown in FIG.
The time T from the falling edge Ta of the same-position signal R0 shown in (c) to the falling edge Tb of the same-position signal R0.
Is measured using the first timer unit 13b, that is, the time T of one rotation (360 degrees) is measured, and the measured time T
Accordingly, the calculation unit 13b determines that the current rotation speed f of the brushless motor 1 is
Is calculated (step ST11).

Incidentally, from the first falling edge Ta of the same position signal R0 after the switching timing of the arrow a shown in FIG. 5A to the same position signal R0 after the switching timing of the arrow c shown in FIG. 5A. Until the first rising edge Tc of the brushless motor 1 is measured by using the first timer unit 7b, that is, the time T / 2 of half rotation (180 degrees) is measured to calculate the current rotation speed f of the brushless motor 1. May be.

Subsequently, the predetermined phase angle data (θ (n)) of the ROM 13a is read according to the calculated rotational speed f, that is, the value (θ (n) for delaying the position signal from the position detection unit 12 by a predetermined phase. )) Is determined (step ST1)
2).

Then, (T / 360) × (30 + θ
(N)) = θW, (T / 360) × (90 + θ (n))
= ΘX and (T / 360) × (150 + θ (n)) =
The time for switching the winding currents for the three phases (the time from the neutral point potential of the induced voltage) is calculated from the equation of θY (step ST13).

Subsequently, the calculated time is shown in FIG.
The times θW, θX, and θY from the time point Tb shown in (4) are set, and the second timer unit 13d that has already started is used to monitor the elapse of the calculated times θW, θX, and θY from the time point Tb. The calculated times θW, θX, and θY may be set in the second timer unit 13d to monitor the elapsed time.

Then, the shortest time θW = (T / 36
When 0) × (30 + θ (n)) has elapsed, step ST
From 14 to ST15, the drive signal switching unit 13e determines that it is the winding current switching timing. For example, as shown in FIG. 5, when the neutral point potential of the position signal R0 is detected at the rising edge and the time θW is calculated, a control signal for switching from driving the transistor W of the inverter unit 2 to driving the transistor U That is, a signal for switching the armature winding current is output. Further, when the neutral point potential of the position signal R0 is detected at the falling edge and the time θW is calculated, the transistor Z of the inverter unit 2
To the drive of the transistor X, that is, a signal for switching the armature winding current is output.

Subsequently, the next short time θX = (T / 36
When 0) × (90 + θ (n)) has elapsed, step ST
The process proceeds from 16 to ST17, and the drive signal switching unit 13e determines that it is the switching timing of the winding current. For example, as shown in FIG. 5, when the neutral point potential of the position signal R0 is detected at the rising edge and the time θX is calculated, a control signal for switching from driving the transistor Y of the inverter unit 2 to driving the transistor Z. That is, a signal for switching the armature winding current is output. Further, when the neutral point potential of the position signal R0 is detected at the falling edge and the time θX is calculated, the transistor V of the inverter unit 2
To the drive of the transistor W, that is, a signal for switching the armature winding current is output.

Then, the longest time θY = (T / 36
0) × (150 + θ (n)) has elapsed, step S
The process proceeds from T18 to ST19, and the drive signal switching unit 13e determines that it is the switching timing of the winding current. For example, in FIG.
As shown in, when the neutral point potential of the position signal R0 is detected at the rising edge and the time θY is calculated, a control signal for switching from driving the transistor U of the inverter unit 2 to driving the transistor V, that is, the armature. A signal for switching the winding current is output. Further, the neutral point potential of the position signal R0 is detected at the falling edge, and the time θY
Is calculated, a control signal for switching from driving the transistor X of the inverter unit 2 to driving the transistor Y, that is, a signal for switching the armature winding current is output.

Further, at the timing of the neutral point potential of the next induced electromotive voltage (Td shown by the arrow in FIG. 5), the position signal R0
The rising edge of is detected, the time for one rotation is measured in the same manner as above, and the number of rotations is calculated from this measured time.
The predetermined angle data (θ (n)) of the ROM 13a is read according to the calculated rotation speed, that is, the position detection unit 12
A value (θ (n)) that delays the position signal from
To decide.

Then, the steps after step ST12 described above are executed to switch the driving of the respective transistors U, V, W, X, Y, Z of the inverter section 2, that is, the respective armature winding currents.

The control circuit 13 repeatedly executes the above-mentioned processing every time the position signal R0 from the position detector 12 is input (or whenever the input changes) during the steady operation of the brushless motor 1. .

As described above, in this embodiment, the correction data (phase angle data) of the position detection timing necessary to switch each armature winding current so that the maximum operating efficiency is obtained in advance for each rotation speed. A table (shown in Table 4) is stored in the ROM 13a.

Further, the neutral point potential of the terminal voltage (induced voltage) of one of the armature windings is detected, and the timing of this neutral point potential is corrected by the angle data of the ROM 13a. By calculating the position detection timing of the rotor 1a for each phase, each armature winding current is switched.

Therefore, the position detection timing that maximizes the operation efficiency can be obtained for each number of revolutions of the brushless motor 1, that is, the armature winding current can be switched at the timing when the operation efficiency is maximized. The same effect as the previous embodiment can be obtained.

Further, since only the terminal voltage (induced voltage) of one armature winding of each armature winding is used, the number of circuit components of the position detecting section 12 can be reduced and the position detecting section 12 can be used for position detection. There is also an advantage that the number of lines is reduced.

In the second embodiment, not only the rotation speed f but also the position detection timing of the rotor 1a is corrected according to the load state of the brushless motor 1 so that each armature winding current is switched. , Better results are obtained. In this case, the load state may be detected by the same method as in the previous embodiment, and the data of the ROM 13a shown in Table 4 may be the one in which the rotation speed f and the load state are taken into consideration as in the previous embodiment. .

FIG. 7 is a block diagram of a controller for a brushless motor showing a third embodiment of the present invention, FIG. 8 is a partial block diagram of a controller for showing this embodiment, and FIGS. 9 and 10 are diagrams. 7 is a time chart for explaining the operation of the control device shown in FIG. 7, and FIGS. 11 and 12 are flowcharts for explaining the operation of the control device shown in FIG. Note that FIG.
The same parts and corresponding parts as in FIG. The timing of arrow O shown in FIG. 9 corresponds to the start timing of FIG.

In the third embodiment, as in the second embodiment, the neutral point potentials of the terminal voltages (induced voltages) of the armature windings of all phases of the brushless motor 1 are set without using the integral filter. In addition to the detection, the position detection timings of all phases are calculated based on the timings of the neutral point potentials so as to maximize the operation efficiency, and the armature winding currents are switched according to these position detection timings.

Therefore, in FIG. 7, the controller for a brushless motor according to the present invention uses, for example, terminal voltages (induced voltages) R, S, of the armature windings of the three-phase brushless motor 1.
A voltage divider circuit 14a for dividing T into a predetermined voltage, and a DC power supply Vcc
A resistor circuit 14b for obtaining a predetermined reference voltage Va from
The divided voltages Ru, Sv, Tw and the predetermined reference voltage V
The position detector 14 including a voltage divider circuit 14a, a resistor circuit 14b, and a comparator circuit 14c is provided with a comparator circuit 14c that outputs a signal of a neutral point potential of the induced voltage of each phase by comparing Position signal R, which is the timing of the sex point potential
0, S0, T0 control circuit (microcomputer) 1
5 is output. The voltage division ratio in the voltage dividing circuit 14a and the resistance ratio in the resistance circuit 14b are set so that the neutral point potential of the induced voltage can be detected.

As shown in FIG. 8, the control circuit 15
Indicates that the position signals R0, S0, T0 from the position detection unit 14 are the signals of the neutral point potential of the induced voltage itself, that is, the signals with no phase delay. Therefore, in addition to the function of the control circuit 7 shown in FIG. , Position signals R0, S from the position detector 14
0 and T0 have a ROM 15a for storing data necessary for delaying a predetermined phase for each rotation speed f (a table similar to Table 4 in the second embodiment), and this predetermined phase delay It has a function of obtaining the position detection timing of the rotor 1a based on the signal of.

The first timer section 15 of the control circuit 15
b, the arithmetic unit 15c, the second timer unit 15d, the drive signal switching unit 15e, and the applied voltage output 15f are the first ones shown in FIG.
The timer unit 7b, the arithmetic unit 7c, the second timer unit 7d, the drive signal switching unit 7e, and the applied voltage output 7f.

Next, the operation of the brushless motor controller having the above structure will be described in detail with reference to the time charts of FIGS. 9 and 10 and the flow charts of FIGS. It is assumed that the circuit 15 operates the brushless motor 1 by the position detection, that is, the steady operation.

Then, the terminal voltage (induced voltage) for three phases
R, S, and T are input to the position detection unit 14, and the voltage dividing circuit 14a of the position detection unit 14 uses terminal voltages R, S, and
T is divided (see FIGS. 9 and 10 (b), (c),
(Shown in (d)). The comparison circuit 14c of the position detector 14 compares the voltages Ru, Sv, Tw obtained by the voltage division with a predetermined reference voltage Va, and a voltage waveform equal to or higher than the predetermined reference voltage Va, that is, a neutral point potential of the induced voltage. A voltage waveform containing information is output to the control circuit 15 (FIGS. 9 and 10).
(Shown in (e), (f), (g)).

On the other hand, the control circuit 15 outputs a control signal and a chopping signal for turning on / off the transistors U, V, W, X, Y and Z of the inverter section 2 in a predetermined manner, and outputs the armature winding currents. Switch. At this time, the position signals R0, S0. The first rising edge or the first falling edge of T0 is detected, and the timing of this edge is determined as the timing of the neutral point potential of the induced voltage. For example, after the switching timing of the armature winding current indicated by the broken lines in FIGS. 9 and 10, the first falling edge or the first rising edge is determined as the timing of the neutral point potential of the induced voltage.

When the control circuit 15 receives the position signals R0, S0, T0 from the position detecting section 14, it starts the second timer section 15d while, for example, as shown in FIGS. 9 (e) and 10 (e). Shown from the falling edge Ta1 of the same position signal R0 to the falling edge Ta of the same position signal R0
The time ta (= T) up to 3 is measured using the first timer unit 15b, that is, the time T of one rotation (360 degrees) is measured, and the operation unit 13b uses the measured time ta to measure the time of the brushless motor 1. The rotation speed f is calculated.

Similarly, based on the position signals S0 and T0 from the position detector 14, the times tb and t of one rotation are obtained.
c (= T) is measured, and the rotational speed f of the bushless motor 1 is calculated from the measured times tb and tc.

It should be noted that from the first falling edge Ta1 of the position signal R0 after the switching timing of the armature winding current shown in FIG. 9 (e) to the beginning of the position signal R0 after the switching timing of the predetermined armature winding. Rising edge Ta2
It is also possible to measure the time T / 2 up to the time t using the first timer unit 7b, that is, measure the time T / 2 of 180 degrees to calculate the rotation speed f of the brushless motor 1.

More specifically, for example, the position signal S0
Due to the neutral point potential of the induced voltage (rising edge Tb
When 1) is detected, the second timer unit 15d is started (step ST20), while the arithmetic unit 15c causes the first timer unit 15b to perform one cycle (360) of the position signal S0.
Degree) to measure the rotation speed f (step S
T21).

Then, the predetermined angle data (θ (n)) of the ROM 15a is read according to the calculated rotation speed f, that is, the value (θ (n) which delays the position signal S0 from the position detection unit 14 by a predetermined phase. )) Is determined (step S)
T22).

Then, (T / 360) × (30 + θ
(N)) = θ (y), the switching timing of the winding current is obtained, that is, the switching timing θ of the armature winding current that maximizes the operating efficiency of the brushless motor 1.
(Y) is calculated (step ST23). This θ (y)
Is the time from time point Tb3.

Subsequently, the second timer unit 15d measures the time from the rising edge Tb3, and when the already calculated time θ (y) has elapsed, the process proceeds from step ST24 to ST25, and the drive signal switching unit 15e Judge as the timing of switching the winding current. Then, as shown in FIGS. 9 and 10, a control signal for switching from driving the transistor U of the inverter unit 2 to driving the transistor V, that is, a signal for switching the armature winding current is output, and the position signal S0 falls. When an edge is detected, a control signal for switching from driving the transistor X to driving the transistor Y, that is, a signal for switching the armature winding current is output.

On the other hand, when the neutral point potential (falling edge Ta1) is detected by the position signal R0, the second timer unit 15d is started (step ST26), while the arithmetic unit 15c is operated by the first timer unit 15b. Position signal R0
One cycle (360 degrees) is measured to calculate the rotation speed f (step ST27).

Subsequently, the predetermined angle data (θ (n)) of the ROM 15a is read out according to the calculated rotation speed f, that is, the value (θ (n) for delaying the position signal R0 from the position detector 14 by a predetermined phase. )) Is determined (step S)
T28).

Then, (T / 360) × (30 + θ
(N)) = θ (y) is used to calculate the switching timing θ (y) of the armature winding current that maximizes the operating efficiency of the brushless motor 1 (step ST29). This θ
(Y) is the time from time point Ta3.

Subsequently, the second timer unit 15d measures the time from the falling edge Ta3, and when the already calculated time θ (y) has elapsed, the process proceeds from step ST30 to ST31 and the drive signal switching unit 15e. Is the switching timing of the winding current. Then, as shown in FIG. 9, a control signal for switching from driving the transistor Z of the inverter unit 2 to driving the transistor X, that is, a signal for switching the armature winding current is output, and the position signal R0 is output.
When the rising edge of
To the drive of the transistor X, that is, a signal for switching the armature winding current is output.

When the neutral point potential (rising edge Tc1) is detected by the position signal T0, the second timer unit 15d is started (step ST32), while the arithmetic unit 15c is operated by the first timer unit 15b. Signal T0
One cycle (360 degrees) is measured to calculate the rotation speed f (step ST33).

Subsequently, the predetermined angle data (θ (n)) of the ROM 15a is read according to the calculated rotation speed f, that is, the value (θ (n) which delays the position signal T0 from the position detection unit 14 by a predetermined phase. )) Is determined (step S)
T34).

Then, (T / 360) × (30 + θ
(N)) = θ (y) is used to calculate the switching timing θ (y) of the armature winding current that maximizes the operating efficiency of the brushless motor 1 (step ST35). This θ
(Y) is the time from time Tc3.

Then, the time from the time Tc3 is measured by the second timer unit 15d, and the time θ already calculated is calculated.
When (y) elapses, the process proceeds from step ST30 to ST31, and the drive signal switching unit 15e determines that it is the winding current switching timing. Then, as shown in FIG. 10, a control signal for switching from driving the transistor V of the inverter unit 2 to driving the transistor W, that is, a signal for switching the armature winding current is output, and the falling edge of the position signal T0 is detected. In that case, a control signal for switching from driving the transistor Y to driving the transistor Z, that is, a signal for switching the armature winding current is output.

As described above, the data is read from the ROM 15a according to the rotation speed f of the brushless motor 1, and the position signals R0 and S from the position detector 14 are read from this data.
The position detection timing obtained by phase correction of 0 and T0 is obtained,
Moreover, the optimum position detection timing that maximizes the operation efficiency of the brushless motor 1 can be obtained. Therefore, the same operation and effect as in the second embodiment can be obtained, that is, the operating efficiency of the brushless motor 1 can always be maximized, and the power consumption can be reduced.

In the above embodiment, the time point Tb1 (Ta1
Or Tc1) to Tb3 (Ta3 or Tc3)
However, the rotation speed f may be calculated by measuring the time from time Tb1 (Ta1 or Tc1) to Tb2 (Ta2 or Tc2).

Further, as in the second embodiment, in addition to the rotation speed, the load state is detected by a voltage change or the like in the inverter section 2, or the discharge pressure or discharge temperature of the compressor, suction pressure or suction temperature, etc. Alternatively, the switching timing of each armature winding current that maximizes the operating efficiency of the brushless motor 1 may be calculated according to the detected load state.

[0100]

As described above, according to the present invention, when the position of the rotor of the brushless motor is detected and a plurality of armature winding currents are switched based on the position detection timing, each armature winding is wound. The neutral point of the induced voltage is detected by the terminal voltage (induced voltage) of the line, and the phase difference from this neutral point to the point (position detection timing) delayed by a predetermined phase is detected by ROM
The armature winding current is switched according to the timing obtained by the obtained phase difference, and the optimum operation efficiency of the brushless motor is maximized for each rotation speed (load state). Since data enabling the calculation of the switching timing of the winding current is stored in the ROM in advance, when controlling the rotation of the brushless motor based on the position detection of the rotor, the rotation speed and the load state can be changed. Regardless of operating efficiency,
As a result, there is a useful effect that power consumption can be reduced and energy can be saved.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a brushless motor control device 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 block diagram of a brushless motor control device according to a second embodiment of the present invention.

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

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

FIG. 7 is a schematic block diagram of a brushless motor control device according to a third embodiment of the present invention.

FIG. 8 is a schematic partial block diagram of the control device shown in FIG. 7.

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

10 is a schematic time chart diagram for explaining the operation of the brushless motor control device shown in FIG. 7. FIG.

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

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

FIG. 13 is a schematic block diagram of a conventional controller for a brushless motor.

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

[Explanation of reference numerals] 1 brushless motor (DC brushless motor) 1a rotor (of the brushless motor 1) 2 inverter unit 3, 12, 14 position detection unit 4, 7, 13, 15 control circuit (microcomputer) 5 chopping unit 6 Driver section 7a, 13a, 15a ROM 7b, 13b, 15b First timer section 7c, 13c, 15c Arithmetic section 7d, 13d, 15d Second timer section 7e, 13e, 15e Drive signal switching section 12a, 14a Voltage dividing circuit 12b, 14b Resistance circuit 12c, 14c Comparison circuit A, B, C Position detection signal R, S, T Terminal voltage of armature winding R0, S0, T0 Position signal U, V, W, X, Y, Z Transistor ( Switching element)

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Hiroyuki Yamamoto 1116 Suenaga, Takatsu-ku, Kawasaki-shi, Kanagawa Within Fujitsu General Co., Ltd. (72) Yoshiyuki Ohara 1116 Suenaga, Takatsu-ku, Kawasaki-shi, Kanagawa

Claims (8)

[Claims] 1. When the position of a rotor of a brushless motor is detected and a plurality of armature winding currents of the brushless motor are switched according to the timing of the position detection to control the rotation of the brushless motor, the rotation of the brushless motor is controlled. The method for controlling a brushless motor is characterized in that the winding current is switched at a phase angle that maximizes the operating efficiency of the brushless motor in accordance with at least the detected number of revolutions. 2. A brushless motor rotor position is detected, and a plurality of armature winding currents (winding currents) of the brushless motor are switched at the position detection timing to control rotation of the brushless motor. The rotation speed of the brushless motor is detected, and the winding is performed at a phase angle that maximizes the operating efficiency of the brushless motor based on the data stored in advance according to the detected rotation speed and a predetermined condition of the load state of the brushless motor. A control method for a brushless motor, characterized in that line current is switched. 3. A brushless motor for detecting the position of a rotor of a brushless motor, and switching a plurality of armature winding currents (winding currents) of the brushless motor at the timing of the position detection to control the rotation of the brushless motor. In the control device, the means for detecting the position of the rotor of the brushless motor and the data for delaying the switching timing of the winding current by the phase angle at which the operating efficiency of the brushless motor is maximized are stored in advance. The storage means and the rotation speed of the brushless motor are detected from the detected rotor position, and at least data corresponding to the detected rotation speed and a predetermined condition is read out from the storage means at a predetermined phase angle. Obtaining the switching timing of the winding current, and based on the obtained timing Control device for a brushless motor, characterized in that a control means for switching the armature winding current. 4. A brushless motor that detects the position of a rotor of a brushless motor, and switches a plurality of armature winding currents (winding currents) of the brushless motor at the timing of the position detection to control the rotation of the brushless motor. In the control device, the means for detecting the position of the rotor of the brushless motor and the data for delaying the switching timing of the winding current by the phase angle at which the operating efficiency of the brushless motor is maximized are stored in advance. A storage unit, a unit for detecting a load state of the brushless motor, and a rotation number of the brushless motor are detected by the detected position of the rotor, and data according to the detected rotation number and the load state is stored. Read from the storage means to obtain the switching timing of the winding current at a predetermined phase angle, and Control device for a brushless motor, characterized in that a control means was based on the switching timing of the winding current switching said plurality of armature winding current. 5. The position of a rotor of a three-phase brushless motor is detected, and three armature winding currents (winding currents) of the brushless motor are switched according to the position detection timing to control the rotation of the brushless motor. Voltage of one armature winding of the brushless motor (induced voltage)
The position of the rotor is detected by, and the rotational speed of the brushless motor is detected by the detected position of the rotor, and the switching timing of the winding current is preset in accordance with at least the detected rotational speed and a predetermined condition. A method of controlling a brushless motor, wherein the switching timing of the winding current is obtained at a phase angle that maximizes the operating efficiency of the brushless motor based on the stored data. 6. The rotation control of the brushless motor is performed by detecting the position of a rotor of a three-phase brushless motor, and switching three armature winding currents (winding currents) of the brushless motor at the timing of the position detection. Voltage (induced voltage) of the three armature windings of the brushless motor
Detects the neutral point potential of the induced voltage, detects the rotational speed of the brushless motor based on the detected neutral point, and switches the winding current according to at least the detected rotational speed and a predetermined condition. A method for controlling a brushless motor, characterized in that the timing of switching the winding current is obtained at a phase angle that maximizes the operating efficiency of the brushless motor based on the data stored in advance. 7. The predetermined condition is that when the brushless motor is a compressor motor, the discharge pressure of refrigerant, the discharge temperature, the suction pressure, the suction temperature, and the voltage applied to each armature winding of the brushless motor are output. The method of controlling a brushless motor according to claim 2, wherein the voltage is at least one of the voltages in the inverter means. 8. The predetermined condition is to output a discharge pressure of refrigerant, a discharge temperature, a suction pressure, a suction temperature, and an applied voltage to each armature winding of the brushless motor when the brushless motor is a compressor motor. The brushless motor control device according to claim 3, wherein the control device is at least one of the voltages in the inverter means.