JP2001057793A - Brushless motor controller with locking decision function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a brushless motor controller with a locking decision function which facilitates alterations of a locking decision time and the numbers times of locking decision without having to remodel a control unit, even if the characteristics of the motor are changed. SOLUTION: A brushless motor controller has a control circuit 7, which generates clock signals synchronized with changes of respective detection signals successively from respective Hall devices, an external capacitor Ca connected to a terminal 3k and a locking decision circuit 4, which compares the potential of the capacitor with a set voltage corresponding to the number of times of locking decision which is set according to the characteristics of a motor main part, while the capacitor is changed/discharged according to the periods of the clock signals from the control circuit 7, and while the potential of the capacitor exceeds the set voltage, causes the outputting of a drive pulse to stop.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outer rotor type brushless motor suitable for driving a blower fan for a vehicle and the like when the rotation of the rotor is in a locked state (a low rotation state below a predetermined value at the time of high speed rotation). The present invention relates to a brushless motor with a lock determination function for performing the following.

[0002]

2. Description of the Related Art In recent years, a brushless motor for switching the direction of an electric current flowing through an armature coil using a commutator and a brush has been used as a motor for a fan of an air conditioner mounted on an automobile. I have.

[0003] This brushless motor has an armature coil,
A motor main body composed of a rotor, a cylinder, a hall element, etc., a driver circuit for supplying drive signals of mutually different phases (offset by 120 degrees) to the armature coil, And a control unit for transmitting a PWM output signal for controlling the number of rotations. This control unit is actually a microcomputer or a custom IC.

In the above-mentioned control unit, while the FAN instruction signal is being input, the rotation speed of the rotor of the motor body is obtained from the period of the detection signal of each Hall element.
A duty ratio for setting the target rotation speed is determined from the rotation speed (duty ratio) indicated by the FAN instruction signal from the air conditioning control amplifier (not shown). And PWM of this duty ratio
The signal is output as an output PWM signal, and is simultaneously transmitted as a plurality of output PWM signals whose timing is shifted for each phase.

Then, a control unit (a microcomputer or a custom I
C) is when the detection signal of the Hall element is not obtained within a predetermined time according to the characteristics of the standard motor, or when the detection signal is input within the predetermined time, the number of times is equal to or less than a predetermined number of times. If the number of inputs is the total number of times, the rotor is locked and the output of the output PWM signal is immediately stopped.

The above-mentioned predetermined time is generally determined according to the characteristics of the motor body.

[0007]

However, the control unit of the conventional brushless motor requires a predetermined time (lock determination time) set in advance according to the characteristics of the standard motor.
If the detection signal of the Hall element cannot be obtained for a predetermined time, a program for performing lock protection (when the control unit is a microcomputer) or an IC circuit (when the control unit is a custom IC)
I have to.

Therefore, when the motor characteristics are different,
There was a problem that a program or a custom IC had to be recreated.

Alternatively, even if a detection signal is input within a predetermined time according to the characteristics of the motor, if the input rotation speed of the detection signal is equal to or lower than a predetermined rotation speed (also referred to as a lock determination rotation speed), the rotor is locked. As a state, the output of the output PWM signal is immediately stopped.

For this reason, when the characteristics of the motors are different, the number of lock determinations must be changed, so that there is a problem that the program or the custom IC must be recreated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a brushless motor with a lock determination function that can easily change the lock determination time and the number of lock determinations without recreating the control unit even if the characteristics of the motor change. The purpose is to obtain a control device.

[0012]

According to the present invention, a plurality of terminals (3a, 3b,...) For connecting the outside and the inside are provided, and a predetermined number of these terminal groups (3i, 3h, 3g) are provided. Via a motor body having a predetermined number of Hall elements for detecting changes in magnetic poles at fixed angular intervals around a rotor (13) having different magnetic poles opposed to each other within a predetermined angular range, and a target rotation signal and In a brushless motor control device that drives a multi-phase armature with a multi-phase drive pulse generated based on each detection signal indicating a change in a magnetic pole, a clock synchronized with a change in each detection signal from each Hall element A control circuit (7) for sequentially generating signals, a capacitor (Ca) externally connected to the terminal (3k), and a capacitor while charging and discharging the capacitor according to the cycle of the clock signal from the control circuit (7). A lock determination circuit (4) for comparing the potential with a set voltage corresponding to a lock determination rotation speed set in accordance with the characteristics of the motor body, and stopping the output of the drive pulse while the set voltage is exceeded; The gist is that

For this reason, when a plurality of driving pulses of different phases are supplied to the plurality of armatures of the motor body, the rotor rotates, and a predetermined number of Hall elements arranged at a constant angular interval are used to change the magnetic pole of the rotor. After passing, from each Hall element,
At the angle interval determined by the arrangement angle and the angle range of each magnetic pole, the detection of the magnetic pole at the time of the previous passage is inconsistent with each other, and each detection signal indicating the change of the magnetic pole in proportion to the cycle of the rotation speed is determined by the control device. It is sent to several terminal groups (3i, 3h, 3g).

Then, the control circuit (7) generates a clock signal synchronized with the change of each detection signal from each Hall element. That is, a clock signal proportional to the cycle of the rotation speed is transmitted at an angular interval determined by the arrangement angle of each Hall element and the angle range of each magnetic pole.

The clock signal is used as a lock determination circuit (4)
Is input, and a terminal (k) is input according to the cycle of the clock signal.
The capacitor (Ca) externally charged and discharged is charged and discharged.

At this time, the lock determination circuit (4) compares the potential of the capacitor (Ca) with the set voltage corresponding to the lock determination rotation speed set according to the characteristics of the motor main body, and exceeds the set voltage. During this period, the output of the drive pulse is stopped.

That is, the charging time for the capacitor (Ca) can be changed by changing the external capacitor (Ca), so that the time required to reach the set time corresponding to the lock determination rotation speed changes. become. That is, the lock determination time can be changed.

The lock judging circuit includes a series circuit (Ra, R) for connecting a plurality of resistors in series to obtain a set voltage at a voltage dividing point.
b) and one input terminal connected to the terminal (3k), and the other input terminal connected to the voltage dividing point of the series circuit, and while the voltage of the capacitor exceeds the voltage set at the voltage dividing point, the motor body (COM1) for transmitting a lock determination signal indicating that the terminal is in a locked state, a terminal (3k) and a comparator (C
Constant current circuit (8) connected to one input terminal of OM1)
And a transistor having a collector connected to the terminal (3k) and the constant current circuit (8) and one input terminal of the comparator (4), an emitter connected to the ground, and a clock input to the base. Is the gist.

For this reason, while the clock signal proportional to the cycle of the rotation speed is being input at an angular interval determined by the arrangement angle of each Hall element and the angle range of each magnetic pole, the clock signal is input to the base of the transistor (TR1). Each time the transistor (T
R1) is turned on to discharge from the external capacitor (Ca) via the terminal (3k).

While the input of the clock signal is stopped, a constant current is charged in the capacitor (Ca).
In other words, the discharge characteristic is a charge characteristic that increases linearly because only the capacitor (Ca) is used.

At this time, the linear voltage of the capacitor (Ca) is compared with the set voltage by the comparator (COMP1), and while the voltage exceeds the set voltage, a lock determination signal is transmitted to rotate the motor body. Be stopped.

That is, lock determination can be performed by a simple analog circuit, and the lock determination time can be changed by changing an external capacitor.

Further, the capacitor (Ca) is connected to the terminal (3
k) and one is connected to a resistor (Rc) connected to a power supply (Vcc). Further, a lock determination circuit includes a series circuit (Ra, Rb) for obtaining a set voltage at a voltage dividing point by connecting a plurality of resistors in series, and one input terminal to a terminal (3k).
The other input terminal is connected to the voltage dividing point of the series circuit, and while the voltage of the capacitor exceeds the voltage set at the voltage dividing point, a lock determination signal indicating that the motor body is in a locked state is transmitted. A comparator (COM1) and a transistor having a collector connected to the terminal (3k) and one input terminal of the comparator (4), an emitter connected to the ground, and a clock input to the base.

For this reason, while a clock signal proportional to the cycle of the rotation speed is being input at an angular interval determined by the arrangement angle of each Hall element and the angle range of each magnetic pole, it is input to the base of the transistor (TR1). Each time the transistor (T
R1) is turned on to discharge from the external capacitor (Ca) via the terminal (3k).

While the input of the clock signal is stopped, the capacitor (Ca) is charged by the power supply Vcc via the resistor (Rc). That is, the discharge characteristics of the capacitor (Ca) are exponentially rounded and have a gentle slope.

At this time, the exponential voltage of the capacitor (Ca) is compared with the set voltage by the comparator (COMP1), and while the voltage exceeds the set voltage, a lock determination signal is sent to rotate the motor body. Is stopped.

That is, the lock can be determined by a simple analog circuit and the external capacitor (Ca)
And the resistance (Rc) gradually increases the discharge characteristic with roundness, so that it takes time to reach the lock determination rotation speed (set voltage). As a result, it is the same as changing the lock determination rotation speed. There will be action.

Therefore, it is only necessary to change the external resistor (Rc) and capacitor (Ca) without changing the set voltage.

Further, when these lock determination circuits and control circuits are integrated, even if the characteristics of the motor change,
You only need to change the external capacitors and resistors.

[0030]

As described above, according to the present invention, the control device generates a clock signal proportional to the period of the rotation speed at an angular interval determined by the arrangement angle of each Hall element and the angle range of each magnetic pole, Terminal (k) according to the cycle of this clock signal
While charging / discharging the capacitor (Ca) externally connected to the motor, the output of the drive pulse is stopped as long as the voltage exceeds the lock determination rotation speed set in accordance with the potential of the capacitor (Ca) and the characteristics of the motor body.

That is, the lock determination time can be changed by changing the external capacitor (Ca).

For this reason, when the characteristics of the motor change, conventionally, when the lock determination is made by a program or a custom IC, the lock is re-created. However, only the external capacitor (Ca) is changed. Is good.

When the lock determination circuit is composed of a series circuit (Ra, Rb) for obtaining a set voltage, a comparator (COM1), a constant current circuit (8), and a transistor,
The lock determination can be performed by a simple analog circuit, and the lock determination time can be changed by changing an external capacitor.

Further, a resistor (R) is connected to the capacitor (Ca).
c), when the lock determination circuit is not provided with a constant current, the lock determination can be performed by a simple analog circuit, and the discharge characteristics are rounded by the external capacitor (Ca) and the resistor (Rc). Since it slowly rises, it takes time to reach the lock determination rotation speed (set voltage). As a result, the same effect as changing the lock determination rotation speed can be obtained.

Therefore, it is only necessary to change the external resistor (Rc) and capacitor (Ca) without changing the set voltage.

Further, when these lock determination circuits and control circuits are integrated, even if the characteristics of the motor change,
You only need to change the external capacitors and resistors.

[0037]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment FIG. 1 is a schematic configuration diagram of a control device for a brushless motor with a lock determination function according to a first embodiment. The control device 1 for a brushless motor shown in FIG. 1 is a custom IC for lock determination.

The control device 1 is connected to a drive circuit 6 for supplying electric power having different phases to the motor main body 2 via terminals 3a to 3f, and to a Hall IC of the motor main body 2 via terminals 3g to 3i. (IC1, IC2, IC3). Each of the Hall elements transmits a normal rotation signal and an inverted signal thereof (collectively referred to simply as a detection signal) for setting the output to an H level upon detection of magnetism.

First, the schematic configuration of the motor body 2 having these Hall element ICs will be described. Motor body 2
As shown in FIG. 2, a magnet 13 (hereinafter, referred to as a sensor magnet 13) for detecting rotation is provided around one end of a shaft 12, and six salient poles 14a, 14b, Stator 1 having...
4 is attached. The aforementioned sensor magnet 13 has a pair of N and N poles, and a pair of S and S poles, respectively.
It is provided around one end of the shaft 12.

The six salient poles 14a, 1
The coils 15a, 15b,... Are wound around 4b,. That is, a six-phase drive system is constituted by the six coils.

As shown in FIG. 2, the main magnets 1 are attached to the rotor 16 outside the stator 14 at intervals of 90 degrees.
7a, 17b,... The rotor 16 is rotatably connected to the other end (not shown) of the shaft 12 integrally with the shaft 12.

Further, the stator 14 has Hall elements 18a (IC1), 18b (IC2), 18c (IC) for detecting the magnetic fields of the magnetic poles (S pole, N pole) of the sensor magnet 13.
3) are evenly arranged at 120 intervals. The S and N poles of the above-mentioned sensor magnet 13 are provided at intervals of 90 degrees, the S and N poles are arranged adjacently, and the S and S poles and the N and N poles are arranged to face each other.

That is, when the rotor 16 rotates 360 degrees, the S-pole and the N-pole sequentially face the Hall elements 18 arranged at 120-degree intervals, so that a detection signal described below is transmitted. However, the output when the N pole and the Hall element face each other is set to the H level (normal rotation).

From the Hall element 18a (IC1), a detection signal SL1 (normal rotation) in which the angle between 30 ° to 120 ° and 210 ° to 300 ° is at H level and a detection signal SH1 obtained by inverting the detection signal SL1 are transmitted. You.

From the Hall element 18b (IC2), L between the angles of 60 to 150 degrees and 240 to 330 degrees
The level-detected signal SL2 (normal rotation) and the inverted detection signal SH2 are transmitted.

Further, from the Hall element 18c (IC3), a detection signal SL3 (normal rotation) in which the angle between 90 degrees to 180 degrees and 270 degrees to 360 degrees is set to the H level, and a detection signal SH3 obtained by inverting the detection signal SL3 are output. Sent out.

That is, the detection signals SL1 and SL are switched by the H-level or the L-level at the above-mentioned angle at the above-described angle while being shifted by 30 degrees in the rotation direction.
2, SL3, SH1, SH2, and SH3.

[0048] These detection signals correspond to H according to the rotational speed.
The interval between the levels or the L levels becomes narrower or longer, but becomes the H level or the L level when between the aforementioned angles. That is, each of the Hall elements has a detection signal SL1, SL2, SL3, SH1, SH2, SH having a cycle corresponding to the rotation speed.
3 is output.

These Hall elements are actually connected to the control unit 1 by two output lines (for normal rotation and inversion), and a total of six are connected to the control unit 1, but in the present description, three Hall elements are used. Only lines are shown.

On the other hand, the drive circuit unit 6 includes the motor control device 1
, And six power elements Q1, Q2,..., Which generate drive signals based on each control signal from the motor control device 1. The drive signal is transmitted to the corresponding power elements Q1, Q2,.

Next, the configuration of the control device 1 will be described. As shown in FIG. 1, the motor control device 1 includes a lock determination circuit 4 therein. As shown in FIG. 1, this lock determination circuit 4 is an open collector type comparator CO.
The circuit includes an MP1, a transistor TR1, voltage dividing resistors Ra and Rb for dividing a Vcc power supply, and a constant current circuit 8.

The comparator COMP1 has a positive input,
It is connected to a constant current circuit 8, a collector of the transistor TR, and an external capacitor Ca via a terminal 3k of the present custom IC (control device). The negative input is connected to the voltage dividing point f of the voltage dividing resistors Ra and Rb. The voltage at the voltage dividing point f is set to a voltage value corresponding to, for example, 50 rotations or less.

That is, when the transistor TR1 is turned off, the lock determination circuit 4 charges a constant current from the constant current circuit 8 to the external capacitor Ca, and the voltage of the capacitor Ca becomes the voltage Vf at the voltage dividing point f. Is reached, a lock state is determined, and a lock determination signal is transmitted.

The control device 1 also includes a sensor input circuit 9
A central control circuit 7 (made of logic), a rotation speed signal shaping circuit 10, a lock maintenance determination circuit 11,
And a drive control circuit 12.

The sensor input circuit 9 includes three comparators (not shown) having hysteresis characteristics, each of which is a Hall IC (IC1, IC2, IC2).
3) comparing the forward and reverse detection signals, and when the difference between the two detection signals exceeds a predetermined value, the output signals S1, S2
2, and S3 are sent to the central control circuit 7, respectively. That is, since this comparator has a hysteresis, the output signals S1 and S1 having a cycle corresponding to the rotation speed of the rotor, which prevents the influence of noise and chattering superimposed on the detection signal.
2, S3 (output signals having phases shifted by 30 degrees in electrical angle).

The central control circuit 7 receives the output signals S1, S2, S3 from the sensor input circuit 9 and receives the output signals S1, S2, S3.
The clock signal CKM is sent to the rotation speed signal shaping circuit 10 every time 1, S2 and S3 are input. That is, the electrical angle 30
3 of the cycle corresponding to the rotation speed of the rotor
By inputting two output signals S1, S2, S3, 12 clock signals CKM are generated per one rotation (360 degrees) of the rotor.

Since the period of the clock signal CKM changes depending on the rotation speed, the period of the output signals S1, S2, S3 becomes shorter or longer, so that the period of the clock signal CKM naturally changes according to the rotation speed. ing.

Further, the central control circuit 7 includes a latch circuit, a select circuit, a transistor drive timing waveform generation circuit, and the like (not shown). The latch circuit receives the output signals S1, S2, and S3 from the sensor input circuit 9, the clock CKM and the advance time setting signal MS (a signal indicating how much the advance is made), and Is performed on the output signals S1, S2, and S3 from. That is, the electrical angle is normalized by the advance time setting signal MS, and the electrical angle 3
Delay is made by subtracting the advance time from the time corresponding to 0 degrees. Then, the signals S1B, S2B,
S3B (hereinafter referred to as post-advance signals S1B, S2B, S3B) is sent to the select circuit 120.

The select circuit inputs both the output signal from the sensor input circuit 9 and the post-advance signal, and outputs the switching instruction signal M
An output signal (also referred to as a pre-advance signal) and a post-advance signal are switched according to the state of the GSEL.

The transistor drive timing waveform generation circuit includes a three-phase control circuit, an overlap circuit, an upper and lower short circuit prohibition circuit, an output OFF circuit, a PWM synthesis circuit, and the like. Signals G1, G2, G3, G4, G5, and G6 are generated using a logic circuit. These signals are signals having an on-time corresponding to an electrical angle of 60 degrees.
2, Q3, Q4, Q5, and Q6. The drive control circuit 1 uses the low side as a PWM signal.
Send to 2. These signals G1, G2, G3, G4, G
The transmission of signals G5 and G6 is stopped by a stop signal from the lock maintenance determination circuit 11 described later.

The rotation speed signal shaping circuit 10 receives a clock signal CK having a cycle corresponding to the rotation speed of the rotor from the central control circuit 7.
M is input, the capacitor Cm is discharged in response to this clock, and the capacitor Cm is charged by a constant current circuit (not shown), thereby generating a "sawtooth wave" corresponding to the rotation cycle of the rotor.

The "saw wave" and the constant voltage R
Compared with ST, the range of the "sawtooth wave" exceeding the constant voltage RST outputs the rotation speed signal CH whose output is at the L level. That is, the pulse width of the clock signal CKM is increased. This is because if the pulse width of the clock signal CKM is narrow, charging of the capacitor Ca is not completed with one pulse. Further, the duty of the "sawtooth wave" changes by changing the capacitor Cm to a capacitor having another capacitance, and the duty of the rotation speed signal CH also changes.

For this reason, for example, when the frequency of the rotation signal CH is converted into a voltage, and the low speed and the high speed are determined according to the voltage value to perform the advance angle control, the motor characteristics are changed by changing the capacitor Cm. The duty ratio of the rotation speed signal CH set accordingly changes.

That is, the "saw wave" and the constant voltage RST
As a result, only by changing the capacitor Cm, the low speed and the high speed can be determined at a high speed according to the motor characteristics.

When the duty ratio of the FAN instruction signal indicates a low rotation or more (for example, 800 rotations), the lock maintenance determination circuit 11 determines whether the rotation speed has reached a value corresponding to the low rotation (100 rotations or less). It is determined to be locked, and an output stop signal is sent to the central control circuit to stop rotation.

The latch is released when the power is turned off or the duty ratio of the FAN instruction signal becomes 10%.

That is, the lock determination signal is charged to the external capacitor Cb, and when the voltage of the capacitor Cb reaches the set voltage Vk corresponding to low rotation, it is determined that the lock is true, and the true lock determination signal is obtained. Is latched until the power is turned off or the duty ratio of the FAN instruction signal becomes 10%. That is, the locked state is maintained.

The operation of the lock determination function of the control device 1 for a brushless motor configured as described above will be described below. FIG. 3 is a timing chart for explaining the operation up to clock generation related to the lock determination according to the first embodiment.

The central control circuit 7 of the control device 1 includes a FAN instruction signal and output signals S1, S2,
A difference based on S3 is set as a target rotation speed, and signals G1, G2, G3, G4, G5, and G6 corresponding to the target rotation speed are sent to the drive control circuit 12 to rotate the rotor of the motor main body 2.

Along with this rotation, the detection signals SL1, SL2, SL3 which are switched by H level or L level at the above-mentioned angle with a shift of 30 degrees in the rotation direction as shown in FIG. , SH1, SH
2, SH3 (the interval between H level and L level changes according to the rotation speed) is input.

The output signals S1, S2, and S3 whose electric angles are shifted by 30 degrees according to the rotation speed of the rotor in which the influence of noise and chattering superimposed on the detection signal are prevented by the comparator of the sensor input circuit 9. Output signal having the same phase).

Next, the central control circuit 7 composed of a digital circuit sends out the clock signal CKM to the rotation speed output circuit 10 every time the output signals S1, S2, S3 are inputted.
That is, by inputting three output signals S1, S2, and S3 having a shift corresponding to the rotation speed of the rotor with a shift of 30 electrical degrees, one rotation (360 degrees) of the rotor is obtained.
Twelve clocks CKM are generated. The interval between the clock signals CKM depends on the number of rotations and the output signals S1 and S1.
2. Since the cycle of S3 becomes shorter or longer,
Naturally, the cycle of the clock signal CKM also changes according to the rotation speed.

The clock signal CKM is input to the rotation speed signal shaping circuit 10 to generate a rotation speed signal CH having a predetermined duty width as shown in FIG.

That is, a rotation speed signal CH is generated with a period proportional to the rotation speed of the rotor and capable of realizing the charging of the capacitor with one pulse.

Then, the rotation speed signal CH is input to the base of the transistor TR1 of the lock determination circuit 4, and as shown in FIG. 4, while the rotation speed signal CH is at the H level, the transistor TR is turned on and the terminal TR is turned on. A discharge current flows from the external capacitor Ca connected to 3k to the ground.

Next, when the rotation speed signal becomes L level, L
During the level, the transistor TR is turned off as shown in FIG. 4, and the constant current from the constant current circuit 8 is supplied to the capacitor C.
a is charged. At this time, the charging characteristic of the capacitor Ca is linear because there is no resistance. The voltage of the capacitor Ca is supplied to the comparator COM via the terminal 3k.
1 to determine whether the comparator COM1 has reached the divided voltage value Vf (set voltage).

For example, as shown in FIG. 4, during normal high-speed rotation, if the rotation speed signal CH becomes H level before the voltage of the capacitor Ca does not reach the set voltage, the transistor TR1 is turned on immediately. Then, the discharge current is discharged from the capacitor Ca to the ground.

Then, the transistor TR1 charges the capacitor Ca with a constant current as soon as the rotation speed signal CH becomes L level. Then, for example, as shown in FIG. 4, when the rotation of the rotor becomes low for some reason, the period of the clock signal CKM from the central control circuit 7 becomes longer. For this reason, even if the voltage of the capacitor ca reaches the set voltage, the rotation speed signal CH does not go to the H level next time.
Reaches the set voltage, a lock determination signal is sent from the comparator COM1 to the lock determination maintaining circuit 11, and the rotation is stopped.

That is, by changing the external capacitor Ca to a capacitor of another capacity, the charging time to reach the set voltage can be easily changed. Therefore, even if the characteristics of the motor change, the internal circuit must be changed. It is only necessary to change the external capacitor Ca.

<Second Embodiment> FIG. 5 is a configuration diagram of a control device 20 of a brushless motor with a lock determination function according to a second embodiment.

As shown in FIG. 5, the lock determination circuit 21 of the control device 20 uses a Vcc power supply without using a constant current circuit.

Further, a connection point kc of the series circuit 22 composed of the capacitor Ca and the resistor Rc is connected to the terminal 3k. One of the resistors Rc of the series circuit 20 is connected to the Vcc power supply.

That is, when the transistor TR1 is turned off, the lock determination circuit 21 of the second embodiment charges the capacitor Ca with the Vcc voltage via the external resistor Rc, and turns on the transistor TR. Occasionally, discharging from the capacitor Ca causes the discharging characteristic to have an exponentially gentle slope.

The control device 20 is the same as that of the first embodiment.
1 includes a sensor input circuit 9, a central control circuit 7, a rotation speed signal shaping circuit 20, a lock maintenance determination circuit 11, and a drive control circuit 12, which are the same as those described above.

That is, the output signal S1, S2, S3 of a cycle corresponding to the rotation speed of the rotor, which is prevented by the comparator of the sensor input circuit 9 from the noise superimposed on the detection signal and the influence of chattering, is formed by a digital circuit. The control circuit 7 controls the clock signal CK corresponding to the rotation speed.
M is generated, and the rotation speed signal shaping circuit 10 generates a rotation speed signal CH having a predetermined duty width from the clock signal CKM as shown in FIG.

Then, the rotation speed signal CH is input to the base of the transistor TR1 of the lock determination circuit 21, and
As shown in (2), while the rotation speed signal CH is at the H level, the transistor TR is turned on to discharge the discharge current from the series circuit 22 including the external resistor Rc and the external capacitor Ca connected to the terminal 3k. Run to ground.

Next, when the rotation speed signal becomes L level, L
Since the transistor TR1 is turned off during the level as shown in FIG. 6, the Vcc voltage charges the capacitor Ca via the resistor Rc.

Therefore, the capacitor C via the resistor Rc
The charging characteristic a has a charging characteristic having an exponential slope as shown in FIG.

The voltage of the capacitor Ca is input to the plus terminal of the comparator COM1 via the terminal 3k, and it is determined whether or not the comparator COM1 has reached the divided voltage Vf (set voltage).

For example, as shown in FIG. 6, when the rotation of the rotor becomes low for some reason and the period of the clock signal CKM from the central control circuit 7 becomes long, the voltage of the capacitor ca reaches the set voltage. Even if the rotation speed signal CH does not become H level next time, the comparator COM
By 1 the voltage of the capacitor Ca reaches the set voltage, a lock determination signal is sent from the comparator COM1 to the lock determination maintaining circuit 11, and the rotation is stopped.

At this time, the discharge characteristic of capacitor Ca has an exponentially rounded gradual slope due to resistance Rc, and thus the set voltage reaches the set voltage more slowly than in the first embodiment.

In other words, since the set voltage is a voltage corresponding to the lock determination rotation speed determined according to the characteristics of the motor, the fact that the set voltage is slowly reached is the same as that of the first embodiment. When the capacitor ca is used, the time until the set voltage is reached is delayed.

That is, since the time required to reach the lock determination rotational speed is delayed by using the external resistor Rc, for example, in the first embodiment, the rotational speed is 800 rpm.
In the above case, if there is no next clock even after waiting for 1 second (less than 100 rpm rotation) and locking is performed, it takes 2 seconds (less than 200 rpm rotation) to reach the set time by using the external resistor Rc. If so, the lock is determined after waiting for a time equivalent to 200 rotations without changing the set voltage (for example, equivalent to 100 rotations).

Therefore, when the characteristics of the motor change,
Even if the resistors Ra and Rb that determine the set voltage are not changed, the same operation as changing the lock determination rotation speed can be achieved by changing the external resistor Rc.

In each of the above embodiments, the rotation speed signal shaping circuit is provided on the assumption that the pulse width of the clock signal CKM is very small. However, when the pulse width of the clock signal CKM is large enough, the rotation speed signal shaping circuit is provided. It is not necessary.

The brushless motor control device according to the present invention is not limited to the use in the blower motor described in the above embodiment, but can be applied to various brushless motors such as a radiator motor.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a control device of a brushless motor with a lock determination function according to a first embodiment.

FIG. 2 is a configuration diagram of a motor main body.

FIG. 3 is a timing chart illustrating an operation up to generation of a clock related to lock determination according to the first embodiment.

FIG. 4 is a timing chart illustrating an operation of the lock determination circuit according to the first embodiment.

FIG. 5 is a schematic configuration diagram of a control device for a brushless motor with a lock determination function according to the second embodiment.

FIG. 6 is a timing chart illustrating the operation of the lock determination circuit according to the first embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 control device 2 motor body 3 a to 3 k terminals 4 lock determination circuit 6 drive circuit 7 central control circuit 8 constant current circuit 9 sensor input circuit 10 rotation speed signal shaping circuit 11 lock maintenance determination circuit 12 drive control circuit 13 sensor magnet COM1 Comparator TR1 Transistor Ra, Rb Voltage dividing resistor Ca capacitor

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Eiji Takahashi 5-24-15 Minamidai, Nakano-ku, Tokyo Calsonic Corporation F-term (reference) 5H560 AA01 BB04 BB08 BB12 DA02 DB02 EB01 JJ07 TT07 UA05 XA04 XA05 XA12

Claims (5)

[Claims] 1. A plurality of terminals (3a, 3b,...) For connecting the outside and the inside are provided, and a predetermined range angle is provided through a predetermined number of these terminal groups (3i, 3h, 3g). A motor body in which a predetermined number of Hall elements for detecting changes in magnetic poles are arranged at fixed angular intervals around a rotor (13) having different magnetic poles opposed to each other is used to detect a target rotation signal and a change in the magnetic pole. A control circuit for sequentially generating a clock signal synchronized with a change in each detection signal from each of the Hall elements in a control device for a brushless motor that drives the armature with a plurality of driving pulses generated based on the signals. (7), a capacitor (Ca) externally connected to a terminal (3k), and the potential of the capacitor while charging and discharging the capacitor according to the cycle of a clock signal from the control circuit (7). A lock determination circuit (4) for comparing with a set voltage corresponding to a lock determination rotation speed set in accordance with characteristics of the motor main body and stopping output of the drive pulse while the set voltage is exceeded. A control device for a brushless motor having a lock determination function. 2. A rotation signal shaping circuit (10) for receiving the clock signal and shaping a pulse width of the clock signal into a predetermined width based on the capacitance of the capacitor. A control device for a brushless motor with a lock determination function as described in the above. 3. The lock determination circuit comprises: a series circuit (Ra, Rb) for connecting a plurality of resistors in series to obtain the set voltage at a voltage dividing point; one input terminal to the terminal (3k); Is connected to the voltage dividing point of the series circuit, and a lock determination signal indicating that the motor main body is in a locked state while the voltage of the capacitor exceeds the set voltage of the voltage dividing point. (COM1), a constant current circuit (8) connected to the terminal (3k) and the one input terminal of the comparator (COM1), and a collector connected to the terminal (3k) and a constant 2. A transistor connected to a current circuit (8) and one input terminal of said comparator (4), an emitter connected to ground, and a base for inputting said clock.
A control device for a brushless motor with a lock determination function as described in the above. 4. The capacitor (Ca) is connected to a terminal (3
k) is connected to a resistor (Rc) having one connected to a power supply (Vcc), and the lock determination circuit is a series circuit for connecting a plurality of resistors in series to obtain the set voltage at a voltage dividing point. (Ra, Rb), and one input terminal connected to the terminal (3k) and the other input terminal connected to the voltage dividing point of the series circuit, and the voltage of the capacitor exceeds the voltage set at the voltage dividing point. And a comparator (COM1) for transmitting a lock determination signal indicating that the motor body is locked, and a collector connected to one of the input terminals of the terminal (3k) and the comparator (4). 2. A control device for a brushless motor with a lock determination function according to claim 1, further comprising a transistor connected to the base, an emitter connected to the ground, and the clock input to the base. 5. The control device for a brushless motor with a lock determination function according to claim 1, wherein said lock determination circuit, control circuit, and rotation speed signal shaping circuit are integrated.