JPH0564486A - Brushless motor - Google Patents

Abstract

PURPOSE:To reduce the number of connecting wires between a sensor unit and a control unit. CONSTITUTION:A microcomputor 21 in a control unit 19 turns a transistor 23 ON/OFF to deliver a voltage signal V0 on a feeder line 20a to a sensor unit 14. A counter circuit 30 takes out detection signals sequentially from Hall ICs 27u-27w according to the voltage signal V0 and delivers the detection signals, as current signals, to the control unit 19. The microcomputor 21 compares the voltage signal V0 with a signal detected through a current detecting resistor 25 thus deciding the detection state of corresponding Hall ICs 27u-27w. According to the invention, only a pair of feeder lines 20a, 20b are required between the control unit 19 and the sensor unit 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor unit having a plurality of position sensors for detecting the rotating state of a rotor, and controlling energization of a stator winding based on a detection signal from the sensor unit. The present invention relates to a brushless motor having a control unit for performing the operation.

[0002]

2. Description of the Related Art FIG. 11 shows an electrical configuration of a sensor unit 1 and a control unit 2 for controlling energization of a brushless motor.

The sensor unit 1 has three Hall ICs 3u, 3 for detecting the rotational position of a rotor (not shown).
v and 3w are arranged so as to have a phase difference of 120 degrees in electrical angle with respect to the rotation direction of the rotor. Both terminals of the parallel circuit of the Hall ICs 3u, 3v, 3w and the capacitor 4 are connected to the power supply lines 6a, 6b via the connector 5. The output terminals of the Hall ICs 3u, 3v, 3w are connected to the signal lines 6c, 6d, 6e via the connector 5.

The power supply lines 6a and 6b are connected to the control unit 2
One of them is connected to the power supply terminal VC of the DC power supply through the connector 7 of
It is connected to C and the other is grounded. Signal lines 6c, 6
d and 6e are the connector 7 and buffer circuits 8u and 8 respectively.
It is connected to the logic circuit section 9 via v and 8w. Each of the input terminals of the buffer circuits 8a to 8c has a resistor 10u,
It is connected to the power supply terminal VCC through 10v and 10w. The logic circuit section 9 outputs control signals from the control output terminals U +, U-, V +, V-, W +, W- based on the detection signals of the Hall ICs 3u, 3v, 3w given through the signal lines 6c to 6e. Then, a switching element (not shown) for controlling energization of the stator winding is ON / OFF controlled.

According to the above construction, when power is supplied from the control unit 2 to the Hall ICs 3u, 3v, 3w via the power supply lines 6a, 6b, the Hall ICs 3u, 3v, 3w act according to the rotational position of the rotor. The magnetic flux to be detected is detected, and a detection signal is given to the logic circuit unit 9 via the signal lines 6c to 6e.

As a result, the Hall ICs 3u, 3v, 3w
According to the detection signal given from the logic circuit unit 9, the logic circuit unit 9 outputs the energization control signal from each of the control output terminals U + to W- corresponding to each of the three phases so as to control the energization to the stator winding. It has become.

[0007]

By the way, in general, when the motor section and the drive circuit section are arranged at distant places, the cost rises and the failure rate increases depending on the number and length of connecting lines between them. It is desirable to reduce the number as much as possible.

However, in the conventional structure as described above, between the sensor unit 1 and the control unit 2,
Since five connection lines of the power supply lines 6a and 6b and the signal lines 6c to 6e are required, the cost and reliability required for wiring increases as the distance between the sensor unit 1 and the control unit 2 increases as described above. Will be disadvantageous in terms of.

The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce the number of connecting wires between a sensor unit and a control unit to reduce cost and failure rate. To provide the motor.

[0010]

SUMMARY OF THE INVENTION According to the present invention, a sensor unit having a plurality of position sensors for detecting the rotation state of a rotor, and a stator winding to a stator winding based on a detection signal from the sensor unit. The present invention is directed to a brushless motor including a control unit that performs energization control, and includes a pair of power supply paths connected between the sensor unit and the control unit, and the power supply path provided in the control unit, through the power supply path. Energization control means for transmitting a voltage signal of a predetermined change pattern to the sensor unit, a power supply circuit provided in the sensor unit for stabilizing the voltage signal and supplying power to the position sensor, and the voltage signal provided in the sensor unit Validating means for sequentially validating and outputting the detection signals from the plurality of position sensors in synchronization with the change pattern of the sensor unit, Current changing means provided in the control unit for changing the current between the pair of power feeding paths according to the output of the validating means, current detecting means provided in the control unit for detecting the current in the power feeding path, and the control means. It is characterized in that it is provided with a judging means which is provided in the unit, and judges the respective detection states of the plurality of position sensors based on the detected current of the current detecting means and the change pattern of the voltage signal.

[0011]

According to the brushless motor of the present invention, when the energization control means transmits a voltage signal of a predetermined change pattern to the sensor unit through the power feeding path, the power supply circuit in the sensor unit supplies drive power to the position sensor. ,
Since the validating means validates the detection signal of the position sensor in synchronization with the voltage signal, when each position sensor is outputting the detection signal at that time, a predetermined current is made to correspond to the power feeding path via the current changing means. Flow at a timing, and this is detected by the current detection means in the control unit. The determination means determines which position sensor is outputting the detection signal based on the detected current and voltage signal change patterns from the current detection means, and detects the rotation state of the rotor. This makes it possible to optimally control the energization of the stator winding. Further, in this case, since it is sufficient to provide only a pair of power supply paths between the sensor unit and the control unit, reliability is improved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS.

In FIG. 2, which shows the overall electrical configuration, a motor section 11 is composed of a three-phase stator winding 12, a rotor 13 having a permanent magnet, and a sensor unit 14 for detecting its rotational position. .. The drive circuit section 15 includes a DC power supply 16, a smoothing capacitor 17, a conduction circuit 18 in which switching elements are bridge-connected corresponding to three phases, and a control unit 19.

In FIG. 1, the connectors 14a and 14b of the sensor unit 14 and the connector 19 of the control unit 19 are shown.
Between a and 19b, a power supply line 20 which is a pair of power supply paths.
a and 20b are connected. The control unit 19 includes
A microcomputer 21 serving as a judging means is provided, and corresponds to each of the three phases from the control output terminals U +, U-, V +, V-, W +, W- based on the signal from the sensor unit 14 as described later. A control signal is output to the energizing circuit 18. The output terminal P of the microcomputer 21 is connected via a resistor 22 to the base of a pnp-type transistor 23 which is an energization control means, and the input terminal Q is connected to the output terminal of a comparator 24.

The transistor 23 has an emitter connected to the DC power supply terminal VCC and a collector connected to the connector 19a. The non-inverting input terminal of the comparator 24 is connected to the connector 19b and is grounded via the current detecting resistor 25 which is a current detecting means. In addition, the comparator 24
A detection reference voltage V1 described later is applied to the inverting input terminal of the.

Next, in the sensor unit 14, the input terminal of the power supply circuit 26 is connected to the connector 14a and the ground terminal is connected to the connector 14b. Hall ICs 27u, 27v, and 27w that are position sensors are the rotor 1
It is arranged so that the change of the magnetic flux with respect to the rotation of 3 has a phase difference of 120 degrees in electrical angle. One input terminal is connected to the output terminal of the power supply circuit 26, and the other input terminal is connected. It is connected to the connector 14b.

The validating means 28 is constructed as follows.
The output terminals of the Hall ICs 27u, 27v, 27w are connected to the respective input terminals of the AND circuits 29u, 29v, 29w, respectively. The counter circuit 30, which is a counter called a Johnson counter, has four output terminals Q1 to Q4, sets the output states of all the output terminals Q1 to Q4 to “L” level by inputting a signal to the clear terminal CL, and clock terminals. Output terminal Q when clock signal is input to CK
The "H" level is output from 1 and the output state of the "H" level is sequentially output each time the clock signal is input.
It is designed to shift after that.

The output terminals Q1 to Q3 of the counter circuit 30 are AND circuits 29u, 29v, 29w, respectively.
Is connected to the other input terminal of each and the output terminal Q4 is AND
The output terminals of the circuits 29u, 29v, and 29w are connected to each input terminal of the OR circuit 31. Counter circuit 30
The clock terminal CK of A together with the output terminal of the OR circuit 31
It is connected to each input terminal of the ND circuit 32. Further, the clear terminal CL of the counter circuit 30 is connected to the connector 14b via the capacitor 33, and is also connected to the output terminal of the comparator 36 via a parallel circuit including the diode 34 and the resistor 35 having the illustrated polarities.

The non-inverting input terminal of the comparator 36 is the connector 1
4a. A predetermined comparison voltage V2 is input to the inverting input terminal of the comparator 36. The current changing means is composed of, for example, an npn-type transistor 38 which is turned on / off according to the output of the enabling means 28, and a current limiting resistor 39 which is connected between the power supply lines 20a and 20b via the transistor 38. .. A
The output terminal of the ND circuit 32 is connected to the base of the transistor 38 via the resistor 37, the collector of the transistor 38 is connected to the connector 14a via the current limiting resistor 39, and the emitter is connected to the connector 14b.

Next, the operation of this embodiment will be described with reference to FIGS. The microcomputer 19 outputs an on / off signal from the output terminal P at a predetermined timing. As a result, the transistor 23 is controlled to be turned on and off, and as shown in FIG. 3A, the voltage signal V0 having different pulse widths is supplied to the sensor unit 1 via the power supply line 20a.
It is transmitted to the 4 side. In this case, the pattern of the voltage signal V0 is the voltage signal VPL for synchronization having a wide pulse width and the following three voltage signals VPK1 to VPK having a narrow pulse width.
One cycle is formed by setting 3 as one set.

When the power supply circuit 26 receives the voltage signal V0 composed of the continuous pulse, the power supply circuit 26 converts it into a stable voltage and outputs it from the output terminal side in the sensor units 14 such as the Hall ICs 27u, 27v, 27w and the counter circuit 30. Power each circuit.

On the other hand, in the comparator 36, the voltage signal V
When the pulses of the voltage signals VPL and VPK1 to 3 included in 0 are received, since the values are set to exceed the predetermined comparison voltage V2, the signal of "H" level is output during the period. As a result, the voltage signals VPL, VPK1 to VPK3 are applied to the clock terminal CK of the counter circuit 30.
"H" level clock pulse PL, PK1 corresponding to
Through PK3 are sequentially input (see FIG. 3 (e)).

Further, the clock pulses PL, PK1 to PK3 pass through an integrating circuit S composed of a capacitor 33 and a resistor 35, and a clear terminal CL of the counter circuit 30.
Entered in. At this time, the input level to the clear terminal CL does not reach the “H” level in the pulse width of the clock pulses PK1 to PK3, but the clock pulse P
The time constant of the integrating circuit S is set so as to reach the “H” level when there is a pulse width of L (see FIG. 3F).

Now, from the comparator 36, the clock pulse PL
Is output, the integration circuit S inputs a signal of “H” level to the clear terminal CL of the counter circuit 30 after a predetermined time has elapsed. As a result, the counter circuit 30 sets all the outputs of the output terminals Q1 to Q4 to the “L” level. Therefore, at this time, the output of the AND circuit 32 also becomes "L" level, and the transistor 38 is turned off.

Subsequently, the clock pulse P is output from the comparator 36.
When K1 is output, the counter circuit 30 receives the “H” level signal at the clock terminal CK,
An "H" level signal is output from the output terminal Q1 (see FIG. 3).
(See (g)). At this time, for example, in FIG.
As shown in (c) and (d), if only the Hall IC 27u inputs a signal of "H" level to the AND circuit 29u, the output terminal of the AND circuit 29u becomes "H" level.

As a result, the AND circuit 32 inputs the "H" level signal from the AND circuit 29u and the comparator 36 via the OR circuit 31, thereby setting the output signal S0 to the "H" level and turning on the transistor 38. It is turned on (see FIG. 3 (k)). As a result, a current flows through the current limiting resistor 39, so the current value I0 flowing through the power supply lines 20a and 20b increases by that amount (FIG. 3 (l)).
reference).

When the energizing current I0 flowing through the power supply lines 20a and 20b increases, the terminal voltage of the current detecting resistor 25 increases in the control unit 19, and the comparator 24 receives a voltage exceeding the reference comparison voltage V1. As a result, an “H” level signal is input to the input terminal Q of the microcomputer 21 (see FIG. 3 (m)). Then, the microcomputer 21 detects that the Hall IC 27u is outputting the "H" level detection signal due to the input of the "H" level signal at the output timing of the voltage signal VPK1.

When the input of the clock pulse PK1 is completed and the output state of the comparator 26 becomes "L" level, AN
The output of the D circuit 32 is also inverted to the “L” level, and the transistor 38 is turned off (see FIG. 3 (k)).

Next, the clock pulse PK is output from the comparator 36.
2 is output, the counter circuit 30 outputs the output terminal Q1.
The output state of "L" level and output terminal Q2
The output state of "H" level (Fig. 3 (g), (h))
reference). At this time, assuming that the output state of the Hall IC 27v is at the “L” level (see FIG. 3C), AN
The output of the D circuit 29v remains at the "L" level, and AN
The output of the D circuit 32 also becomes "L" level. Therefore, the transistor 38 is turned off.

Similarly, when the clock pulse PK3 is output from the comparator 36, the AND circuit 32 outputs a signal corresponding to the output state of the Hall IC 27w. In this case, the transistor 38 is not turned on because the output of the Hall IC 27w is at "L" level. As a result, the microcomputer 21 operates the Hall IC until the clock pulse PK3 is output.
The detection signal of "H" level is obtained only from 27w.

Subsequently, when the clock pulse PL is output again from the comparator 36, the counter circuit 30 sets the output state of the output terminal Q3 to "L" level and the output state of the output terminal Q4 to "H". To level. This gives A
The ND circuit 32 outputs a signal of "H" level to turn on the transistor 38. On the other hand, since a signal of "H" level is input to the clear terminal CL of the counter circuit 30 by the action of the integrating circuit S, the counter circuit 30 sets the output of the output terminal Q4 to "L" level. Turning off the transistor 38.

Thereafter, the clock pulse PK is output from the comparator 36.
When 1 to PK3 are sequentially output, the Hall ICs 27u and 27 are input to the input terminal Q of the microcomputer 21 at each output timing of each clock pulse PK1 to PK3.
A detection signal indicating the output state of v, 27w is input, and thus the rotation state of the rotor 13 can be detected.

Therefore, for example, when the comparator 36 outputs the second clock pulse PK2, FIG.
When the Hall IC 27w is outputting a signal of "H" level as shown in, the detection signal corresponding to this is input to the input terminal Q of the microcomputer 21.

Now, in the microcomputer 21, according to the detection signal inputted in this way, as shown in FIG.
These signals are judged based on the flow chart of the program shown in. That is, the microcomputer 21
The voltage signal VPK1 (clock pulse PK1) is output (step S1), and it is determined whether the detection signal input to the input terminal Q at that time is "H" level (step S1).
2) When it is at "H" level, it is assumed that the Hall IC 27u is in the "H" level detection state (step S3).
If not, it is determined that the Hall IC 27u is in the "L" level detection state (step S4), and the voltage signal VP is detected.
The output of K1 is stopped (step S5).

Subsequently, the microcomputer 21 outputs the voltage signal VPK2 (clock pulse PK2) (step S6) and similarly determines the detection state of the Hall IC 27v (steps S7 to S10), and further, the voltage signal VPK3. (Clock pulse PK3) is output to determine the detection state of the Hall IC 27w (steps S11 to S15).

Next, the microcomputer 21 outputs the above-mentioned voltage signal VPL (clock pulse PL) (step S16), thereby judging whether or not the "H" level signal is input to the input terminal Q. Yes (step S1
7). That is, when the counter circuit 30 is not adversely affected by noise or the like, the counter circuit 30 sets the output terminal Q3 to the "L" level by the clock pulse PL and outputs the output terminal Q.
4 to the "H" level, the microcomputer 2
The "H" level signal is always input to 1. Therefore, the microcomputer 21 returns "YES".
Then, the process proceeds to step S18, an energization signal for the energizing circuit 18 is generated and output based on the above-described detection signal, and the process proceeds to step S19.

In step S17, the microcomputer 21 does not input the signal of "H" level, so that "NO".
If it is determined that the normal operation as described above is not performed due to noise or the like being input as a clock pulse to the counter circuit 30, the determination result of the output state of the Hall ICs 27u to 27w in that cycle (step S4, S9, S14) are not used as output control signals. That is, the process proceeds to step S19 without passing through step S18.

Next, the microcomputer 21 stands by for a certain period of time in step S19, and then continues to step S19.
At 20, the reset terminal CL of the counter circuit 30 receives a “H” level signal after a lapse of a certain time, so that all the output terminals Q1 to Q4 become “L” level and the input terminal Q receives an “L” level. Given the signal
It is determined to be "YES" and the output of the voltage signal VPL is stopped (step S21). As a result, the detection operation for one cycle is completed, and the microcomputer 21 returns to step S1 again to repeat the above program.

On the other hand, when the "L" level signal is not given to the input terminal Q in step S20, the microcomputer 21 determines that the counter circuit 30 is not normally reset and is in an abnormal state, and the step S20 is performed.
At step 22, the detection operation is stopped, and an abnormal action such as an informing operation is performed, and this state is maintained until the abnormal state is released.

Hall IC 27 detected in this way
The signals u, 27v, and 27w are obtained according to the rotation state of the rotor 13 as shown in FIGS. 5 (a) to 5 (c). As shown, a control signal can be output from the control output terminal to the energizing circuit 18 to energize the stator winding 12.

According to the present embodiment as described above, the microcomputer 21 gives the voltage signal V0 to the sensor unit 14 from the control unit 19 side through the power supply lines 20a and 20b in a predetermined change pattern, and the sensor unit 14 is supplied.
Hall ICs 27u, 27v, 2 by the validation means 28 of
7w detection signals are sequentially validated, and the detection signals are used as current signals via the power supply lines 20a and 20b to control unit 1
Since the transmission is made to the 9 side, the power supply lines 20a, 20b
Besides, it is not necessary to separately provide a signal line, so that the wiring and connector parts can be simplified, downsizing and cost reduction can be achieved, and the restriction of the motor structure due to the connection line can be relaxed, By reducing the number of connecting wires, it is possible to improve reliability in the connection-related part.

FIG. 7 shows the second embodiment of the present invention.
The difference from the embodiment is the change pattern of the voltage signal V0. That is, in the first embodiment, the voltage signal VPL
Is a pulse signal having a wider width than the other voltage signals VPK1 to VPK3, in the present embodiment, the voltage signal V
The voltage signal VPL 'corresponding to PL is changed to another voltage signal VPK.
1 to VPK3 is different in that the voltage value is larger than that of VPK3. Correspondingly, in the sensor unit 14, a clock is applied to the clear terminal CL of the counter circuit 30 only for such a voltage signal VPL '. If the configuration is such that a pulse is input, the same operation and effect as in the first embodiment can be obtained.

FIG. 8 shows the third embodiment of the present invention.
The difference from the embodiment is the change pattern of the voltage signal V0. That is, in this case, the analog signal has a linear output voltage having a peak voltage level corresponding to the voltage signal VPL. Then, the sensor unit 14 detects this voltage signal at a plurality of comparison levels and outputs clock pulses PK1 to PK3.
By generating a pulse corresponding to
The same operation and effect as in the first embodiment can be obtained.

FIG. 9 shows the fourth embodiment of the present invention.
The difference from the embodiment is that the Hall IC 27 that transmits from the sensor unit 14 side via the power supply lines 20a and 20b.
That is, the method of transmitting u, 27v, and 27w detection signals is changed.

That is, in the first embodiment, as shown in FIG. 4, the current corresponding to the detection signals of the Hall ICs 27u, 27v, 27w is made to flow at the output timing of the clock pulses PK1 to PK3. On the other hand, in the present embodiment, the detection signal is transmitted as follows.

There are a maximum of 8 combinations of the output states of the Hall ICs 27u, 27v, 27w obtained by the detection in one cycle (actually, all are "L" or all "H" in the normal state). However, when eight clock pulses PK1 to PK8 are sequentially given by the microcomputer 21 corresponding to each of these combinations, depending on which clock pulse the input signal is obtained to the microcomputer 21, IC27u, 27
The detection states of v and 27w are determined. Then, the validating means 28 is configured as a circuit in which logic circuits are combined so as to correspond to such a signal output.

Therefore, the same effect as that of the first embodiment can be obtained by the fourth embodiment.

FIG. 10 shows a fifth embodiment of the present invention. The difference from the first embodiment is that the Hall IC 2 that transmits from the sensor unit 14 side through the power supply lines 20a and 20b.
The way of transmitting the detection signals of 7u, 27v, and 27w is changed.

That is, as in the fourth embodiment, 1
Hall IC 27u, 2 obtained by detection in cycle
For 8 combinations of 7v and 27w output states (actually, all are not “L” or all “H” in the normal state), the microcomputer 21
When the voltage signal V0 is output from the control unit 19 side, the respective detection states of the Hall ICs 27u, 27v, 27w are determined depending on how many pulses are input to the microcomputer 21. Then, the validating means 28 is configured as a circuit in which logic circuits are combined so as to correspond to such a signal output.

Therefore, the same effect as that of the first embodiment can be obtained by the fifth embodiment.

[0051]

As described above, according to the brushless motor of the present invention, the control unit transmits a voltage signal of a predetermined change pattern, and the sensor unit activates the detection signals of a plurality of position sensors. Since the signals are sequentially enabled and transmitted via the power feeding path, the wiring between the sensor unit and the control unit can be configured to have only a pair of power feeding paths, thus increasing the distance between the two. Even in such a case, it is possible to reduce the number of wirings, alleviate the restriction on the motor structure and reduce the size, and to improve the reliability of the connection line portion, without significantly increasing the cost. Play.

[Brief description of drawings]

FIG. 1 is an electrical configuration diagram showing a first embodiment of the present invention.

FIG. 2 is an overall electrical configuration diagram

FIG. 3 is a time chart showing an output state of each unit.

FIG. 4 is a correspondence diagram between a Hall IC detection signal and an input signal to a microcomputer.

FIG. 5: Correspondence diagram of Hall IC detection signal and control signal output to energizing circuit

FIG. 6 is a flowchart showing control contents by a microcomputer.

FIG. 7 is a pattern diagram of energizing voltage showing a second embodiment of the present invention.

FIG. 8 is a diagram corresponding to FIG. 7 showing a third embodiment of the present invention.

FIG. 9 is a view corresponding to FIG. 4 showing a fourth embodiment of the present invention.

FIG. 10 is a view corresponding to FIG. 4 showing a fifth embodiment of the present invention.

FIG. 11 is a view corresponding to FIG. 1 showing a conventional example.

[Explanation of symbols]

11 is a motor part, 12 is a stator winding, 13 is a rotor, 1
4 is a sensor unit, 15 is a drive circuit section, 18 is an energization circuit, 19 is a control unit, 20a and 20b are power supply lines (a pair of power supply paths), 21 is a microcomputer (determination means), and 23 is a transistor (energization control means). ), 24 is a comparator, 25 is a current detecting resistor (current detecting means), 26 is a power supply circuit, 27a to 27c are Hall ICs (position sensors), 28 is an enabling means, 30 is a counter circuit, 36 is a comparator, Reference numeral 38 is a transistor (current changing means), and 39 is a current limiting resistance (current changing means).

Claims (1)

[Claims] 1. A sensor unit having a plurality of position sensors for detecting a rotating state of a rotor, and a control unit for controlling energization of a stator winding based on a detection signal from the sensor unit. In a brushless motor provided with a pair of power supply paths connected between the sensor unit and the control unit, and energization for transmitting a voltage signal of a predetermined change pattern to the sensor unit via the power supply path provided in the control unit. Control means, a power supply circuit provided in the sensor unit for stabilizing the voltage signal to supply power to the position sensor, and detection by the plurality of position sensors provided in the sensor unit in synchronization with a change pattern of the voltage signal. Validating means for sequentially validating and outputting signals, and corresponding to the output of the validating means provided in the sensor unit Current changing means for changing the current between the pair of power feeding paths, a current detecting means provided in the control unit for detecting the current of the power feeding path, and a current detected by the current detecting means provided in the control unit, A brushless motor, comprising: a determination unit that determines each detection state of the plurality of position sensors based on a change pattern of the voltage signal.