JP3364153B2 - Brushless motor and brushless motor drive circuit - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a permanent magnet field type brushless motor, and more particularly, to a brushless motor to which another brushless motor can be connected, and
The present invention relates to a brushless motor drive circuit capable of collectively driving the brushless motor and other brushless motors in a sensorless manner.

[0002]

2. Description of the Related Art Conventionally, a sensorless drive circuit for a brushless motor has focused on a correlation between a speed electromotive force generated in an armature winding of a brushless motor being rotationally driven and a position of a magnetic field, and the brushless motor is driven by the speed electromotive force. The brushless motor is rotationally driven without a sensor by determining the commutation timing of the motor and commutating the brushless motor in accordance with the commutation timing.

[0003]

[Problems to be Solved by the Invention]
Since there is no choice but to detect using the armature winding voltage of the brushless motor, when a plurality of brushless motors are connected to one brushless motor drive circuit, the armature winding voltage of each brushless motor is detected individually. I can't. Therefore, the speed electromotive force of each brushless motor cannot be detected, and as a result, the commutation timing of the brushless motor cannot be determined. As described above, in the sensorless drive circuit of the brushless motor based on the speed electromotive force, there is a problem that a plurality of brushless motors cannot be connected to one circuit and rotationally driven without a sensor.

The present invention has been made in order to solve the above-mentioned problems, and a brushless motor to which another brushless motor can be connected, and the brushless motor and another brushless motor are collectively sensorless. An object of the present invention is to provide a brushless motor drive circuit that can be rotationally driven.

[0005]

In order to achieve this object, a brushless motor and a brushless motor according to claim 1.
The motor drive circuit is connected to the plural-phase armature windings and the plural-phase armature windings, and is connected to another brushless motor .
A brushless motor having a connector member formed to be connectable with a plurality of phase armature windings, and the brushless motor
Connected to the multi-phase armature winding of the
And other brushless connected to the connector member
Sequentially apply DC voltage to the multi-phase armature winding of the motor
Circuit having a plurality of switching elements for
And multiple switching elements of the inverter circuit
The brushless motor is turned on or off to perform commutation.
And another brushless model connected to the connector member.
Power control circuit for rotating the motor, and the brushless motor
And another brushless model connected to the connector member.
The current flowing in the armature winding of the
Current detection circuit that converts the voltage into a single voltage and detects the voltage
Based on the detection voltage of the current detection circuit,
A series motor and another block connected to the connector member.
The total value of the current that flows through the armature winding of the rackless motor.
And detect the second region of increased current in one commutation cycle.
And commutate to the energization control circuit at the detected timing.
Outputs a command, the brushless motor and the connector
Commutation of each other brushless motor connected to the member
And a commutation command circuit. Brushless motor
Rotation of the motor causes the motor's field to
The positional relationship changes. With this change, armature winding
The value of the current flowing through the line also changes. The brushlet according to claim 1.
Motor and brushless motor drive circuit
Determining the commutation timing by paying attention to changes in the child current
Allows the brushless motor and other brushless motors to
This enables sensorless driving of the data. In particular,
As shown in FIG. 1, the armature is driven while the brushless motor is being driven.
When the winding is energized, the current value flowing in the armature winding is
It shows a marked increase over two times (41, 42). Yo
Therefore, this second remarkable current increase region 42 (second electric current
The flow increase area) is detected to determine the commutation timing.
is there. That is, the brushless motor and the bra according to claim 1.
Connected to the inverter circuit according to the serial motor drive circuit
Brushless motor armature winding and connector
Another block connected to the brushless motor by a member.
The armature winding of the rackless motor is controlled by the energization control circuit.
The switching element of the inverter circuit is turned on
Meanwhile, the armature current flows. Armature of each brushless motor
The current is detected by the current detection circuit at least for each energized phase.
Are converted into a single voltage and detected.
Based on the pressure, the commutation command circuit enables brushless motor
And other brushless motors connected to the connector member
Commutation period of 1 for the total value of the current flowing in the armature winding
The arrival of the second current increase region at is detected. this
The commutation command is issued at the timing when the second current increase region arrives.
A commutation command is output from the circuit to the energization control circuit, and the commutation
Based on the command, the energization control circuit
The switching element is turned on or off. This allows
Brushless motors and other blocks connected to connector members
The brushless motors are commutated and each brushless motor
It is rotated without a sensor.

A brushless motor according to a second aspect is a brushless motor according to the first aspect and a brushless motor drive.
In the brushless motor of the circuit, the brushless motor
The connector member of the motor includes a motor connection terminal formed to be connectable to another brushless motor, and the motor connection terminal is a brushless motor for sequentially applying a DC voltage to the plurality of phase armature windings. It is also used as a circuit connection terminal for connecting a drive circuit.

A brushless motor according to a third aspect is a brushless motor according to the first aspect and a brushless motor drive.
In the brushless motor of the circuit, the brushless motor
The connector member includes a circuit connection terminal to which a brushless motor drive circuit that sequentially applies a DC voltage to the armature windings of the plurality of phases can be connected, and a motor connection terminal to which another brushless motor can be connected. The motor connection terminals are connected to the plural-phase armature windings. According to the brushless motor of the third aspect, the brushless motor and the brushless motor drive circuit of the first aspect operate in the same manner as the brushless motor, and the brushless motor is connected via the circuit connection terminal of the connector member. A drive circuit is connected, and a DC voltage is sequentially applied to the armature windings of multiple phases by the brushless motor drive circuit. Moreover, since the motor connection terminals of the connector member are connected to the multi-phase armature windings, the brushless motor drive circuit energizes other brushless motors connected via the motor connection terminals. Be seen.

[0008] The brushless motor of claim 4 wherein the billing
Item 1. Brushless motor and brushless motor drive according to item 1.
A brushless motor for a circuit or the circuit according to claim 2 or 3.
In the brushless motor, wherein the core member the armature winding of multiple <br/> number phase of the brushless motor is wound, wound armature windings of a plurality of phases of the brushless motor and its core member wherein The connector board of the brushless motor is connected, and a connector board on which the connector member is mounted is provided, and the connector board is attached to the iron core member.

[0009]

[0010]

[0011]

[0012]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. The operating principle of the brushless motor drive circuit in this embodiment is described in Japanese Patent Application No. 7-207665.
The description is omitted.

FIG. 2 is an external perspective view of a brushless motor 1 according to an embodiment of the present invention. Brushless motor 1
Uses the field of a permanent magnet as a rotor, and three phases (U phase, V phase,
This is a surface magnet type brushless motor using a W-phase) armature winding as a stator, and includes a case body 2 formed in a substantially cylindrical shape. The case body 2 of this brushless motor 1 is
It is for covering the field of the permanent magnet and the three-phase armature winding described above, and is formed by press-molding a thin plate-shaped steel material.

The left end surface of the case body 2 (left side in FIG. 2)
A cylindrical shaft-shaped rotor shaft 3 extending outward from the case body 2 is rotatably projectingly provided on the outer surface of the case body 2. The brushless motor 1 is attached to various devices at the left end of the outer periphery of the case body 2. Rectangular plate-shaped three (plural) rib members 2 for
a are circumferentially provided at substantially equal intervals. These rib members 2a are formed with through holes 2b for screwing the brushless motor 1 to the frame of various devices, respectively. Bolts are inserted through the through holes 2b to form the rib members 2a. The brushless motor 1 can be attached and fixed to various devices by screwing the to the frame of various devices.

A connector 4 is arranged on the right side (the right side in FIG. 2) of the outer periphery of the case body 2 around which the rib members 2a are provided. This connector 4 is 3 of the brushless motor 1.
Brushless motor drive circuit 2 to be described later on the phase armature winding
1 and a three-phase armature winding of the brushless motor 1 of the same model, which is provided with a substantially rectangular parallelepiped housing 4a made of synthetic resin having no conductivity such as ABS resin. . The motors of the same model are motors having substantially the same speed electromotive force constant, torque constant, and inertia (moment of inertia).

FIG. 3A is an enlarged perspective view of the connector 4 provided in the brushless motor 1, and FIG.
3 is an external perspective view of a connection cable 10 including a connector 11 that is attachable to and detachable from a connector 4 arranged in the brushless motor 1. FIG. In addition, in FIG. 3B, a part of the three wiring cords 12 is omitted.

As shown in FIG. 3A, the housing 4a
On the right side of the front of the, three pin terminals 4b1-4
b3 project outwards at substantially equal intervals, and three substantially cylindrical pin terminals 4b4 to 4b6 project outward at substantially equal intervals on the left side of the front surface of the housing 4a. It is set up. These pin terminals 4b1 to 4b6
Is an electrode terminal for connecting the brushless motor 1 of the present embodiment to the brushless motor drive circuit 21 and the brushless motor 1 of the same model. Has been formed. Further, on the front surface of the housing 4a, around the pin terminals 4b1 to 4b6, cylindrical protection walls 4a1 to 4a are provided.
6 are circumferentially provided, and a predetermined gap is formed between the inner peripheral surfaces of the protection walls 4a1 to 4a6 and the outer peripheral surfaces of the pin terminals 4b1 to 4b6.

The protective walls 4a1-4a6 are pin terminals 4b1.
4b6 are to prevent an electric shock from being brought into contact with a finger or the like, and are made of a synthetic resin having no conductivity such as an ABS resin to have substantially the same shape. These protection walls 4a1 to 4a6 are formed so as to project forward from the pin terminals 4b1 to 4b6, respectively.
The inner diameter of 4a6 is smaller than that of the fingertip. Therefore, the protection walls 4a1 to 4a6 can prevent a finger or the like from coming into contact with any of the pin terminals 4b1 to 4b6 and receiving an electric shock.

The connection cable 10 is a cable for connecting the connector 4 of the brushless motor 1 of this embodiment and the connector 4 of the brushless motor 1 of the same model, and as shown in FIG. Three wiring cords 12 including a pair of connectors 11 formed in a shape and lead wires for electrically connecting the pair of connectors 11
It has and. Since the pair of connectors 11 are formed in the same shape, only one connector 11 will be described below.

The connector 11 of the connection cable 10 is provided with a substantially rectangular parallelepiped housing 11a, which is made of a synthetic resin having no conductivity such as ABS resin. Housing 11 of this connector 11
On the front surface of a, there are three circular fitting holes 11a1 to 11a3.
Are recessed at substantially equal intervals, and these fitting holes 11a1 to 11a3 are provided in the protective wall 4 of the connector 4 described above.
The a1 to 4a3 or the protective walls 4a4 to 4a6 are formed so as to be fitted to each other. Therefore, when the connector 11 is attached (coupled) to the connector 4, these fitting holes 1
1a1 to 11a3 include protective walls 4a1 to 4a3 of the connector 4
Alternatively, since the protection walls 4a4 to 4a6 are fitted into each other, it is possible to prevent the connector 11 from falling off the connector 4.

Inside the fitting holes 11a1 to 11a3, socket terminals 11b1 to 11b3, which are made of a conductive material such as tin-plated phosphor bronze and are formed in a substantially cylindrical shape, are provided. These socket terminals 11b
1 to 11b3 are the pin terminals 4b1 of the connector 4 described above.
4b3 to 4b3 or pin terminals 4b4 to 4b6, the pin terminals 4b1 to 4b3 are formed in a substantially cylindrical shape for fitting therein.
Alternatively, by internally fitting the pin terminals 4b4 to 4b6, the pin terminals 4b1 to 4b3 or the pin terminal 4b.
It is connected to 4-4b6. At one end of each wiring cord 12 (left side of FIG. 3B), the connector 11 (FIG.
Socket terminals 11b1 to 11b3 on the left side of (b) are connected to each other, and the other end of each wiring cord 12 (see FIG. 3).
To the right side of (b), the socket terminals 11b1 to 11b3 of the connector 11 (right side of FIG. 3B) are respectively connected.

The end faces of the socket terminals 11b1 to 11b3 are the front faces of the housing 11a, that is, the fitting holes 11a.
The fitting holes 11a1 to 11a3 are formed to have inner diameters smaller than the fingertips. Therefore, the fitting holes 11a1-11
Since a finger or the like is prevented from entering a3, it is possible to prevent the finger or the like from contacting any of the pin terminals 4b1 to 4b6 and receiving an electric shock.

FIG. 4 is a cross-sectional view of the brushless motor 1. As shown in FIG. 4, a substantially cylindrical yoke 5 made of a magnetic material such as soft iron is provided inside the case body 2 described above.
Six teeth 5 a extending toward the center of the case body 2 are provided on the inner peripheral surface of the yoke 5 so as to protrude at substantially equal intervals. These teeth 5a are made of a magnetic material such as soft iron and have substantially the same shape. A coil winding made of a magnet wire or the like is provided between the inner ends of the teeth 5a and the case body 2 side end. Each wire 6 is wound. As described above, in the brushless motor 1 according to the present embodiment, the six coil windings 6 wound around the six teeth 5a of the yoke 5 are provided.
The three phases (U phase, V
Phase, W phase) armature winding.

A substantially C-shaped thin-plate connector substrate 7 is fixed to the yoke 5 by screwing. The connector board 7 is a known printed circuit board, and the connector 4 described above is mounted on the front surface (component surface) thereof. On the rear surface (upper side in FIG. 4) of the housing 4a of the connector 4, that is, on the side of the protection walls 4a1 to 4a3 opposite to the protruding surface,
Similar to the pin terminals 4b1 to 4b6 described above, three connecting pieces 4c1 to 4c3 formed of a conductive material such as tin-plated phosphor bronze are provided. Of these connection pieces 4c1 to 4c3, the connection piece 4c1 is the pin terminal 4b1.
And the connection piece 4c fixed to the pin terminal 4b4, respectively.
2 is fixed to the pin terminals 4b2 and 4b5, respectively, and the connection piece 4c3 is fixed to the pin terminals 4b3 and 4b6, respectively.

Circuit patterns 7a to 7c are formed by etching on the back surface (solder surface) of the connector substrate 7 on which the connector 4 thus constructed is mounted, and one end of each circuit pattern 7a to 7c is formed. The connection pieces 4c1 to 4c3 of the connector 4 are connected to the respective sides by soldering or the like. On the other hand, the coil windings 6 constituting the U-phase, V-phase and W-phase of the armature winding are connected to the other ends of the circuit patterns 7a to 7c by soldering or the like. That is, the coil windings 6 forming the U-phase of the armature winding of the brushless motor 1 are connected to the pin terminals 4b1 and 4b4 respectively via the circuit pattern 7a and the connecting piece 4c1, and the V-phase of the armature winding is connected. Coil winding 6
Are respectively connected to the pin terminals 4b2 and 4b5 via the circuit pattern 7b and the connecting piece 4c2, and the coil winding 6 constituting the W phase of the armature winding is connected via the circuit pattern 7c and the connecting piece 4c3. It is connected to the pin terminals 4b3 and 4b6, respectively.

As described above, since the coil windings 6 forming the three-phase armature windings of the brushless motor 1 are connected to the pin terminals 4b1 to 4b6 of the connector 4 via the connector substrate 7, respectively. It is not necessary to connect the coil winding 6 forming the three-phase armature winding and the pin terminals 4b1 to 4b6 of the connector 4 by the aerial wiring such as a lead wire. Therefore, it is possible to prevent the aerial wiring from being entangled with the rotor 8 to be described later and hindering the rotation of the rotor 8. Moreover, since the connector substrate 7 is fixed to the yoke 5 by screwing, the connector substrate 7
It is possible to dispose the connector 4 mounted on the brushless motor 1 without rattling.

Inside the yoke 5 to which the connector substrate 7 is fixed and inside the six teeth 5a, a rotor 8 axially supported in the front-rear direction of FIG. 4 is rotatably provided. The rotor shaft 3 described above is driven into the central portion of the rotor 8. A pair of known radial bearings 8a are provided at both ends of the rotor shaft 3 in the axial direction (direction perpendicular to the plane of FIG. 4), and the rotor shaft 3 is rotatable by the pair of radial bearings 8a. It is pivotally supported. In addition, in FIG. 4, among the pair of radial bearings 8a, the rotor shaft 3
Only the radial bearing 8a that axially supports the end portion on the back side of the is illustrated.

An annular rotor core 8b made of a magnetic material such as soft iron is externally fitted to the outer circumference of the rotor shaft 3 which is axially supported by the pair of radial bearings 8a. On the outer peripheral surface of the rotor core 8b, four magnet members 8c, which are curved in conformity with the curved surface, are adhered, and these magnet members 8c are each formed of a known permanent magnet. Out of these magnet members 8c, adjacent magnet members 8c are magnetized with different polarities on the outer peripheral surface sides thereof. For example, the upper right part of the rotor core 8b (see FIG.
When the outer peripheral surface side of the magnet member 8c bonded to the upper right of the magnet member 8c is magnetized to the positive electrode (plus pole or N pole), the outer peripheral surface sides of the two magnet members 8c adjacent to the magnet member 8c are respectively It is magnetized to the negative electrode (minus pole or S pole). That is, the outer peripheral surface side of the magnet member 8c adhered to the lower right part of the rotor core 8b (lower right part of FIG. 4) and the outer periphery of the magnet member 8c adhered to the upper left part of the rotor core 8b (upper left part of FIG. 4). The surface side is magnetized to a negative electrode (minus pole or S pole). On the other hand, in such cases,
The outer peripheral surface side of the magnet member 8c bonded to the lower left part of the rotor core 8b (lower left part of FIG. 4) is a positive electrode (plus pole or N pole).
Is magnetized. As described above, in the brushless motor 1 of the present embodiment, the rotor 8 having the four magnet members 8c bonded to the rotor core 8b constitutes a four-pole field.

FIG. 5 is a partial vertical sectional view of the brushless motor 1. As shown in FIG. 5, the pin terminal 4 described above is used.
b2 and the left end of the pin terminal 4b5 (on the left side of FIG. 5),
The connection pieces 4c2 described above are fixed to each other, and the pin terminals 4b2 and 4b5 are connected via the connection pieces 4c2. Moreover, the lower end of the connecting piece 4c2 is soldered to the circuit pattern 7b of the connector substrate 7, and is connected to the coil winding 6 that constitutes the V-phase armature winding through the circuit pattern 7b. ing.
That is, the pin terminals 4b2 and 4b5 are connected to the coil winding 6 that constitutes the V phase of the armature winding via the connection piece 4c2 and the circuit pattern 7b. Although not shown in FIG. 5, the connecting pieces 4c1 and 4c3 described above are formed in substantially the same shape as the connecting piece 4c2. Moreover, the pin terminals 4b1 and 4b4 are connected to the coil winding 6 that constitutes the U-phase armature winding through the connecting piece 4c1 and the circuit pattern 7a, and the pin terminals 4b3 and 4b6 are connected to the connecting piece 4c3 and the circuit. It is connected to the coil winding 6 that constitutes the W-phase armature winding via the pattern 7c.

Next, with reference to FIG. 6, a method of connecting the connector 4 of the brushless motor 1 configured as described above will be described. FIG. 6 shows a brushless motor 1 of the same model.
It is a circuit diagram in the state where a plurality of are connected in parallel. still,
In FIG. 6, two brushless motors 1 of the same model are connected in parallel.

As shown in FIG. 6, two (plural) brushless motors 1 of the same model are connected in parallel to the brushless motor drive circuit 21. The brushless motor drive circuit 21 is provided with output terminals R, S, and T respectively connected to the three-phase armature windings of the brushless motor 1, and these output terminals R to T have three leads. Through the wires, they are respectively connected to the socket terminals 11b1 to 11b3 of the connector 11 of the same type as the connector 11 described above. Socket terminals 11b to 11b of this connector 11
3 are connected to pin terminals 4b1 to 4b3 of the connector 4 of the brushless motor 1 (upper side in FIG. 6), and these pin terminals 4b1 to 4b3 are the three-phase armature windings of the brushless motor 1 described above. Are connected to the respective coil windings 6 (see FIG. 4).

The pin terminals 4b1 to 4b3 of the connector 4 of the brushless motor 1 are connected to the pin terminals 4b4 to 4b6.
Are respectively connected, and these pin terminals 4b4 to
The socket terminals 11b1 to 11b3 of the connection cable 10 described above are connected to 4b6, respectively. One end of each of the three wiring cords 12 is connected to the socket terminals 11b1 to 11b3 of the connection cable 10, and the socket terminals 11b1 to 11b3 connected to the other ends of the three wiring cords 12 are connected to the socket terminals 11b1 to 11b3. , The pin terminals 4b1 to 4b3 of the connector 4 of the brushless motor 1 (the lower side in FIG. 6) of the same model are respectively connected. As described above, according to the brushless motor 1 of this embodiment, a plurality of brushless motors 1 of the same model can be connected to the brushless motor drive circuit 21 via the connector 4 and the connection cable 10 described above.

FIG. 7 is a circuit diagram of a sensorless DC brushless motor drive circuit 21 for driving the brushless motor 1, and in FIG. 7, a connection cable 10 for connecting a plurality of brushless motors 1 and a brushless motor drive circuit 21. Connector 11 for connecting to the brushless motor 1
Are omitted in the figure. The brushless motor drive circuit 21 drives a small PM brushless motor for an indoor fan, a transfer device in which load torque can change suddenly, and a brushless motor for an outdoor fan of an air conditioner which is easily disturbed by gusts and the like at a variable speed. It is used as a sensorless drive circuit for In addition, a motor with a slip ring that uses a field magnet as a stator and an armature winding as a rotor, a brushless motor with an embedded magnet, and an outer rotor motor that has a stator inside and a rotor outside The brushless motor drive circuit 21 can be used.

In this brushless motor drive circuit 21,
Output terminals R, S, T connected to the three-phase armature windings of the brushless motor 1 are provided respectively, and an inverter circuit 23 is connected to these output terminals R, S, T. The output terminal R connected to the inverter circuit 23,
S and T are respectively connected to the socket terminals 11b1 to 11b3 of the connector 11 of the same type as the above-mentioned connector 11 via three lead wires. To the socket terminals 11b to 11b3 of the connector 11, five brushless motors 1 of the same model are connected in parallel via the connector 4 described above. The brushless motors 1 connected to one brushless motor drive circuit 21 must be the brushless motors 1 of the same model. However, if the brushless motors 1 of the same model are used, two or more brushless motor drive circuits 21 can be provided in one brushless motor drive circuit 21. The brushless motor 1 can be connected. The number of brushless motors 1 that can be connected is determined by (maximum output current of the inverter circuit 23) / (maximum current of the brushless motor 1).

The auxiliary power supply circuit 22 of the brushless motor drive circuit 21 is stable from a 30 volt DC power supply 50.
It is a circuit that generates and outputs a voltage of 0 volt. The voltage of 10 V generated by the auxiliary power supply circuit 22 is supplied as a drive voltage to each circuit such as the starting compensation circuit 27 and the commutation command circuit 29.

The inverter circuit 23 is a circuit for sequentially energizing and switching a DC voltage of 30 V to the three-phase (U-phase, V-phase, W-phase) armature windings of a plurality (five) of brushless motors 1. Is. At the positive side input terminal P of the DC power supply 50 of the inverter circuit 23, 3 as an upper arm transistor is connected.
P-MOS field effect transistors Qu, Qv, Qw
Of the lower arm transistor is connected to the ground side input terminal N of the DC power supply 50.
The source terminals of the MOS field effect transistors Qx, Qy, Qz are connected to form three arms corresponding to the three-phase armature windings.

The upper arm transistors Qu to Qw are connected to the outputs u to w of the distribution circuit 32 via the resistors Ru1 to Rw1 having gate terminals of 10 kΩ, respectively, and the outputs u to w of the distribution circuit 32 are selected. It is configured to be turned on and off (see FIG. 8B). A resistor R of 47 kΩ is provided between the gate and source of the upper arm transistors Qu to Qw for protection and prevention of floating gate voltage.
u2 to Rw2 and the lower arm transistors Qx to Qz when turned on by chopper control, the upper arm transistors Qu to Qw corresponding to the lower arm transistors Qx to Qz.
Of the lower arm transistors Qx to Qz and the short-circuit preventing capacitor (100
0 pF) Cu to Cw are connected to each other.

On the other hand, the gate terminals of the lower arm transistors Qx to Qz are respectively connected to the outputs x to z of the distribution circuit 32 via the resistors Rx1 to Rz1 of 1 kΩ, and the inverters Ix to Iz as chopper drivers are connected. It is connected to the output end of the chopper control circuit 38 via. Each of the inverters Ix to Iz is composed of an open collector type NPN digital transistor whose emitter terminal is connected to the ground side input terminal N of the DC power supply 50 (that is, circuit ground). Therefore, the lower arm transistors Qx to Qz are turned on / off according to the outputs x to z of the distribution circuit 32 and the output of the chopper control circuit 38. Specifically, when a low signal is output from the chopper control circuit 38 to turn off the collector-emitter of the inverters Ix to Iz and a high signal is output from the outputs x to z of the distribution circuit 32, The arm transistors Qx to Qz are turned on. That is, as shown in FIGS. 8 (a) and 8 (b),
The lower arm transistors Qx to Qz are chopper-controlled according to the output of the chopper control circuit 38.

Resistors Rx2 to Rz2 of 5.6 kΩ for protection and gate voltage floating prevention are respectively connected between the gate and source of the lower arm transistors Qx to Qz. Also, each arm transistor Qu
A freewheel diode Du for circulating a current caused by a back electromotive force generated in the armature windings of the brushless motors 1 when the arm transistors Qu to Qz are turned on and off. Dz
Are connected in anti-parallel, respectively.

The current detection circuit 24 collects the currents flowing through the armature windings of a plurality (five) of brushless motors 1,
This is a circuit for converting this into a voltage and outputting it to the harmonic elimination circuit 33. This current detection circuit 24 is connected to the DC power source 5
It is composed of a shunt resistor Rs of 0.1 Ω (2 W) inserted between the ground side input terminal N of 0 and the inverter circuit 23. The three-phase armature currents of the five brushless motors 1 are all voltage-converted by the shunt resistor Rs, except for the return current to the freewheel diodes Du to Dz. Note that FIG. 8C shows an output voltage waveform of the current detection circuit 24 during normal operation of the brushless motor 1.

The harmonic wave removing circuit 33 synchronizes with the chopper control by the chopper control circuit 38 to synchronize with the inverter circuit 2.
3 is a circuit for storing the output voltage of the current detection circuit 24 while the lower arm transistors Qx to Qz of No. 3 are turned on and outputting it to the sampling circuit 25 and the commutation command circuit 29. That is, the higher harmonic components due to the chopper control are removed, and the output voltage of the current detection circuit 24 is output to the sampling circuit 25 and the commutation command circuit 29. The harmonic elimination circuit 33 includes an analog switch AS1, a capacitor C1, a resistor R3 that functions as an RC low-pass filter together with the capacitor C1, and a non-inverting amplifier configured by resistors R4 and R5 and an operational amplifier OP1.

One of the channel terminals of the analog switch AS1 is connected to the current detection circuit 24 via a resistor R3 of 550Ω.
, And the other channel terminal is connected to a 0.1 μF capacitor C1 whose one end is circuit grounded. The gate of the analog switch AS1 is connected to the output end of the chopper control circuit 38 via the inverter Ia, and while the chopper control circuit 38 outputs the low signal (the inverter circuit 2 is controlled by the chopper control).
3 while the lower arm transistors Qx to Qz are turned on), the analog switch AS1 is turned on. Therefore, the output voltage of the current detection circuit 24 is
Lower arm transistor Qx by chopper control circuit 38
The data is stored in the capacitor C1 in synchronization with the ON operation of Qz. Therefore, the output voltage of the current detection circuit 24 from which the harmonic component is removed by the chopper control can be stored in the capacitor C1 together with the RC low-pass filter composed of the resistor R3 and the capacitor C1.

The inverter Ia is composed of an open collector type NPN digital transistor whose emitter is grounded, and is connected to the 10 volt output of the auxiliary power supply circuit 22 via a pull-up resistor R6 of 1 kΩ. .

The non-grounded end of the capacitor C1 is connected to the non-inverting input end of the operational amplifier OP1. The operational amplifier OP1 constitutes a non-inverting amplifier together with the resistors R4 and R5. Since the resistance value of the resistor R4 is 47 kΩ and the resistance value of the resistor R5 is 10 kΩ, the output of the capacitor C1 is amplified to about 5.7 times by the non-inverting amplifiers OP1, R4 and R5, and its output terminal is amplified. It is output to the commutation command circuit 29 via the sampling circuit 25 and R16 connected to. That is, the output voltage of the current detection circuit 24, after the harmonic component is removed by the harmonic removal circuit 33,
The sampling circuit 25 and the R are amplified by about 5.7 times.
It is output to the commutation command circuit 29 via 16. Figure 8
The output voltage of the harmonic elimination circuit 33 is shown in FIG.

The non-inverting amplifiers OP1, R4 and R5
Can be eliminated by increasing the resistance value of the shunt resistor Rs of the current detection circuit 24. For example,
Change the resistance value of the shunt resistor Rs from the current 0.1Ω to 1
If it is set to 0 times 1Ω, the output voltage of the current detection circuit 24 will also be 1.
It is multiplied by 0. Therefore, in such a case, the output of the capacitor C1 may be output to the sampling circuit 25 and the commutation command circuit 29 without passing through the non-inverting amplifiers OP1, R4, and R5. In this embodiment, the resistance Rs having a small resistance value is used in order to suppress the temperature rise of the shunt resistance Rs.

The sampling circuit 25 is a circuit for storing the instantaneous value of the output voltage of the harmonic elimination circuit 33 and outputting the instantaneous value to the amplifier circuit 26. The sampling circuit 25 includes an analog switch AS2 and a capacitor C2.
And resistors R7 and R8. One channel terminal of the analog switch AS2 is connected to the output terminal of the harmonic elimination circuit 33, and the other channel terminal of the analog switch AS2 is connected through a resistor R7 having a resistance of 1 kΩ.
Of the capacitor C2 and the resistor R8 of 1 MΩ. The gate of the analog switch AS2 is connected to the output end of the commutation command circuit 29, and while the high commutation command 56 is output from the commutation command circuit 29 (see FIG. 8 (g)), the analog switch AS2 is turned on.

The capacitor C2 is an analog switch AS.
While 2 is on, it is connected to the output terminal of the harmonic elimination circuit 33 via the resistor R7. This capacitor C2 has a resistor R7
An RC low-pass filter is also configured to remove harmonic components that cannot be removed by the harmonic removal circuit 33, and
The output voltage of the harmonic elimination circuit 33 is stored. The non-ground terminal of the capacitor C2 is only connected to the analog switch AS2 via the resistor R7, the resistor R8, and the non-inverting input terminal of the operational amplifier OP2 of the amplifier circuit 26.
Moreover, since the resistance value of the resistor R8 is very large as 1 MΩ, the voltage value of the capacitor C2 is the analog switch AS2.
Is held for a predetermined time even after turning off. Therefore, the capacitor C
In 2, the voltage value (instantaneous output) of the harmonic wave removing circuit 33 immediately before the analog switch AS2 is turned off is stored.

The commutation command 56 is, as will be described later,
When the output voltage of the harmonic elimination circuit 33 via R16 becomes larger than the output voltage of the sampling circuit 25 amplified by the amplifier circuit 26, it is output from the commutation command circuit 29. Therefore, if a large voltage value is held in the capacitor C2 of the sampling circuit 25 for some reason, the output voltage of the harmonic elimination circuit 33 cannot be larger than the amplified output voltage of the sampling circuit 25.
Since the commutation command 56 cannot be generated, the brushless motor 1
Will stop.

However, since the resistor R8 is connected in parallel to the capacitor C2 of the sampling circuit 25, the electric charge accumulated in the capacitor C2 is gradually discharged by the resistor R8, albeit little by little, and as a result, the capacitor R2 is discharged. The voltage value of C2 also gradually decreases. Therefore, the resistance R
By connecting 8 to the capacitor C2 in parallel, the commutation command 56 can be regenerated without fail even if a large voltage value is held in the capacitor C2, and the brushless motor 1 may be stopped. Absent.

The resistance value of the resistor R8 is equal to that of the capacitor C2.
And the lower limit value of the commutation frequency of the inverter circuit 23 at the time of starting. That is, when the lower limit value of the commutation frequency at the time of starting is set to around 2 Hz, a time constant slightly larger than the cycle of 12 Hz which is six times that is set, and the resistance is set to be in the range of about 0.1 seconds. The resistance value of R8 and the capacitance of the capacitor C2 are determined. In this embodiment, since the capacitance of the capacitor C2 is 0.1 μF,
The resistance value of the resistor R8 is set to 1 MΩ.

Depending on the type of the operational amplifier OP2 of the amplifier circuit 26, a leak current (input bias current) may flow from the non-inverting input terminal to the ground. In such a case, the leakage current causes the voltage value of the capacitor C2 to rise, that is, the commutation target voltage, which is the stored voltage value of the harmonic elimination circuit 33, changes in the rising direction. , The normal commutation operation cannot be performed. However, by connecting the resistor R8 in parallel with the capacitor C2, such a leak current can be passed through the resistor R8, so that the voltage value of the capacitor C2 can be prevented from rising and the voltage value of the capacitor C2 must be lowered. In this case, the capacitor C2 can maintain the output voltage of the harmonic elimination circuit 33.

The amplifier circuit 26 is a circuit for amplifying the voltage value stored by the sampling circuit 25 and outputting it to the priority circuit 28. The amplifier circuit 26 is an operational amplifier OP2.
And a 10 kΩ two resistors R9 and R10, and a 100 kΩ variable resistor VR1 that reduces the output of the non-inverting amplifier to less than 1 time. The variable resistor VR1 slides. The commutation target voltage during steady operation is output from the child end.

The operational amplifier OP2 of the non-inverting amplifier is connected at its non-inverting input terminal to the capacitor C2 which is the output terminal of the sampling circuit 25, and at the output terminal of the operational amplifier OP2, a resistor R9 and a variable resistance whose circuit ground is provided at one end. VR1
Are connected. The other end of the resistor R9 has an operational amplifier OP
2 is connected to the inverting input terminal and one end of the resistor R10, and the other end of the resistor R10 is circuit grounded.

The two resistors R9 and R10 of the non-inverting amplifier have the same resistance value of 10 kΩ. Therefore, the output of the sampling circuit 25 is the non-inverting amplifier OP.
2, R9 and R10 amplify the signal approximately twice. The output of the sampling circuit 25 amplified twice is the variable resistance VR.
It is output to the priority circuit 28 after being reduced to 1 times or less by the variable resistor VR1. In the present embodiment, the output of the sampling circuit 25, which is doubled by the non-inverting amplifiers OP2, R9, and R10, is reduced to 0.7 times by the variable resistor VR1. Therefore, the output of the sampling circuit 25 as a whole of the amplifier circuit 26 is amplified by 1.4 times. FIG. 8E shows the output voltage waveform of the amplifier circuit 26.

As a matter of course, the variable resistor VR1
Since the amplification factor of the entire amplification circuit 26 can be changed by adjusting the slider position of, the amplification factor can be changed according to the usage situation. That is, the brushless motor 1 can be tuned so that the motor efficiency is most improved in the normal operation region.

The starting compensation circuit 27 is used for the brushless motor 1
Is a circuit for outputting a commutation target voltage to the commutation command circuit 29 in place of the amplified output of the sampling circuit 25 so that the brushless motor 1 can generate a sufficient starting torque at the time of starting. . This starting compensation circuit 2
7 operates in conjunction with the output of the chopper control circuit 38. That is, when the duty ratio of the chopper control output from the chopper control circuit 38 is increased from a small value less than the predetermined value to a predetermined value or more, for example, in the present embodiment, the row output duty ratio is about 3.8. From less than about 3.8%
In the above case, the starting compensation circuit 27 outputs the commutation target voltage at the time of starting to the commutation command circuit 29 via the priority circuit 28. In addition, the duty ratio of about 3.8% described above is obtained by the resistors R32 (390Ω) and R33 (10k).
Ω).

The starting compensation circuit 27 is the chopper control circuit 3
It has a resistor R31 of 100 kΩ connected to the output terminal of 8, and the other end of the resistor R31 is connected to one end of a 0.1 μF capacitor C11 and the inverting input terminal of the operational amplifier OP11. The other end of the capacitor C11 is connected to the 10-volt output of the auxiliary power supply circuit 22. One end of the operational amplifier OP11 is connected to the non-inverting input end of the auxiliary power supply circuit 22.
390Ω resistor R32 connected to the 10 volt output of
Is connected to a resistor R33 of 10 kΩ whose one end is circuit grounded. The output terminal of the operational amplifier OP11 is
It is connected to the anode of the diode D11 and the positive side terminal of the electrolytic capacitor C12 of 10 μF. The cathode of the diode D11 is connected to the 10-volt output of the auxiliary power supply circuit 22, while the negative terminal of the electrolytic capacitor C12 is a circuit grounded resistor R34 of 100 kΩ.
It is connected to the cathode of a diode D12 whose anode is grounded, and to one end of a 500 kΩ variable resistor VR2. The other end of the variable resistor VR2 is connected to one end of a resistor R35 of 100 kΩ, and the other end of the resistor R35 is connected to the anode of the diode D3 which is the input end of the priority circuit 28 as the output end of the starting compensation circuit 27. There is.

Here, the operation of the starting compensation circuit 27 will be described with reference to FIGS. 9 and 10. The voltage dividing ratio of the variable resistor VR4 of the speed setting circuit 36 is set low (see FIG. 9).
(A) A) When the duty ratio of the row output of the chopper control circuit 38 is less than about 3.8% (see FIG. 9).
(B) A): The chopper pulse output from the chopper control circuit 38 is absorbed (suppressed) by the capacitor C11 forming the low-pass filter of the starting compensation circuit 27, so the input voltage to the inverting input terminal of the operational amplifier OP11 is ,
The voltage applied to the non-inverting input terminal by the resistors R32 and R33 is about 9.62 V or higher (Fig. 9 (c) A).
In such a case, the output voltage of the operational amplifier OP11 is 0 volt (FIG. 9 (d) A). Therefore, when the duty ratio of the low output of the chopper control circuit 38 is less than about 3.8%, the output voltage from the starting compensation circuit 27 is 0 volt (FIG. 9 (e) A). In this state, the brushless motor 1 is in a stopped state.

From this state, the voltage division ratio of the variable resistor VR4 of the speed setting circuit 36 is increased (FIG. 9A), and the duty ratio of the row output of the chopper control circuit 38 is set to about 3.8.
% (FIG. 9 (b) B), the starting compensation circuit 27
The discharge of the capacitor C11 of can not follow the charge,
The input voltage to the inverting input terminal of the operational amplifier OP11 is about 9.
It drops below 62 volts (Fig. 9 (c) B). as a result,
The input voltage to the non-inverting input terminal of the operational amplifier OP11 becomes higher than the input voltage to the inverting input terminal, and the operational amplifier OP11
The output voltage of 11 rises from 0 volt to about 8.5 volt (FIG. 9 (d) B). Here, about 8.5 V is the limit value of the output voltage determined by the characteristic of the operational amplifier (the operational amplifier can output only up to 1.5 V or less of the power source voltage due to the characteristic, and in this embodiment, the power source voltage of the operational amplifier OP11 is used. Is 10 volt, so 10 volt-1.5 volt = 8.5 volt (the 1.5 volt value naturally varies depending on the type of operational amplifier).

The output voltage of the operational amplifier OP11 is about 8.5.
When the voltage becomes volt, a voltage of about 8.5 volt is applied to the differentiating circuit composed of the capacitor C12 and the resistor R34. Therefore, from the starting compensation circuit 27, the variable resistor VR2
A differential pulse-like voltage wave gradually decreasing from the voltage value of less than 8.5 V, which is obtained by subtracting the voltage drop, with time, is output to the priority circuit 28 via the resistor R35 (FIG. 9 (e)). ) B). Since the capacitance of the capacitor C12 is 10 μF and the resistance value of the resistor R34 is 100 kΩ, this voltage wave occurs after 1 second (10 μF × 100 kΩ = 1.
In s), it is reduced to about 37% of its peak value.

Starting compensation circuit 2 output to priority circuit 28
The output voltage of 7 is used as the commutation target voltage, and the commutation command circuit 29
Is output to. Therefore, the commutation target voltage at the time of starting the brushless motor 1 is set high, and at the time of starting the plurality of brushless motors 1, an armature current sufficient to generate a starting torque flows (see FIG. 9 (f) B). ), The plurality of brushless motors 1 are started accurately.

On the other hand, when the voltage division ratio of the variable resistor VR4 of the speed setting circuit 36 is lowered during the rotation of the brushless motor 1 (FIG. 10 (a)), the duty ratio of the row output of the chopper control circuit 38 is lowered and the brushless motor is brushless. The effective value of the voltage applied to the motor 1 also drops, and the brushless motor 1 is decelerated. Then, when the duty ratio of the low output of the chopper control circuit 38 falls below about 3.8% (FIG. 10 (b)), the capacitor C3 of the starting compensation circuit 27.
Charge cannot follow the discharge, and the operational amplifier OP1
1, the input voltage to the inverting input terminal rises above the input voltage to the non-inverting input terminal of 9.62 volts (see FIG.
(C)), the output voltage of the operational amplifier OP11 drops from about 8.5 V to 0 V (FIG. 10 (d)). When the output voltage of the operational amplifier OP11 becomes 0 volt, the electric charge charged in the capacitor C12 is rapidly discharged through the diode D12 and the operational amplifier OP11, and the initial state is restored.

From this state, the voltage division ratio of the variable resistor VR4 of the speed setting circuit 36 is increased again (FIG. 10 (a)),
When the duty ratio of the low output of the chopper control circuit 38 becomes about 3.8% or more (FIG. 10 (b)), the operational amplifier O
The input voltage to the inverting input terminal of P11 falls below 9.62 volts (FIG. 10 (c)), and the output voltage of the operational amplifier OP11 rises to about 8.5 volts (FIG. 10 (d)). As a result, the differential voltage pulse wave is output again from the starting compensation circuit 27 until the discharged capacitor C12 is recharged (FIG. 10 (e)).

When the DC power supply 50 is turned off while the brushless motor 1 is being driven, the electric charge stored in the capacitor C12 is rapidly discharged through the diodes D11 and D12, and the initial state is restored. Therefore, even when the DC power supply 50 is turned on again immediately after it is turned off, the starting compensation circuit 27 is normally operated and the brushless motor 1 is operated.
Can be started smoothly.

As described above, in the starting compensation circuit 27 of this embodiment, even if the voltage division ratio of the variable resistor VR4 of the speed setting circuit 36 is lowered and the plurality of brushless motors 1 being driven are stopped or rotated at low speed. , Then variable resistance VR
By increasing the voltage division ratio of 4, the commutation target voltage sufficient for starting the plurality of brushless motors 1 can be output from the starting compensation circuit 27. Therefore, even in such a case, the plurality of brushless motors 1 can be started accurately. In this way, the starting compensation circuit 27 is configured to operate in conjunction with the speed setting by the variable resistor VR4 of the speed setting circuit 36.

The priority circuit 28 outputs the output of the sampling circuit 25 amplified by the amplifier circuit 26, that is, the commutation target voltage in the steady operation and the output of the starting compensation circuit 27.
That is, it is a circuit for outputting the larger output voltage of the commutation target voltage at the time of starting to the commutation command circuit 29, and is configured by the diode D3. The diode D3 has its anode connected to the output end of the starting compensation circuit 27, and its cathode connected to the output end of the amplifier circuit 26 and the inverting input end of the comparator CP1 which is one input end of the commutation command circuit 29. Has been done. Therefore, the priority circuit 28 outputs the larger output voltage of the amplification circuit 26 and the start compensation circuit 27 to the commutation command circuit 29 as the commutation target voltage.

The commutation command circuit 29 is used for the brushless motor 1
The commutation command 56 of the counting circuit 31 and the sampling circuit 2
5 and a circuit for outputting to the zero reset circuit 30, which is mainly composed of a comparator CP1 and a monostable multivibrator MM1. The inverting input terminal of the comparator CP1 is connected to the output terminal of the priority circuit 28, while the non-inverting input terminal is connected to the output terminal of the harmonic elimination circuit 33 via the resistor R16. Further, the output end of the comparator CP1 is a monostable multivibrator MM.
The output terminal Q of the monostable multivibrator MM1 which is connected to the input terminal A of 1 and issues a commutation command has an input terminal CK of the counting circuit 31, the gates of both analog switches AS2 and AS3 of the sampling circuit 25 and the zero reset circuit 30. It is connected to the.

Further, the commutation command circuit 29 includes a diode D4.
The anode of the diode D4 is connected to the output end of the sample time correction circuit 39, and the cathode is connected to one end of a variable resistor VR3 of 100 kΩ. The other end of the variable resistor VR3 has a resistor R1 of 10 kΩ.
5 is connected to one end of the resistor R15, the other end of which is 0.1 μF.
End of the condenser C5 and the monostable multivibrator M
It is connected to M1. The other end of the capacitor C5 is also connected to the monostable multivibrator MM1.

In the commutation command circuit 29, the comparator CP
1 compares the output voltage of the harmonic elimination circuit 33 with the output voltage of the priority circuit 28. As a result of the comparison, when the output voltage of the harmonic elimination circuit 33 becomes larger than the output voltage of the priority circuit 28, as shown in FIG. It is output to the input terminal A. As a result, as shown in FIG. 8 (g), a one-shot high signal (commutation command 56) is output from the output terminal Q of the monostable multivibrator MM1 to the counting circuit 31. In addition,
This commutation command 56 is simultaneously output to the gates of the analog switches AS2 and AS3 of the sampling circuit 25 and the zero reset circuit 30, and while both are high, both switches AS are turned on.
2, AS3 is turned on.

The sampling circuit 25 holds the instantaneous output of the harmonic elimination circuit 33 immediately before the analog switch AS2 is turned off. This analog switch AS2
Since it is turned on while the high commutation command 56 is being output, the sampling circuit 25 holds the instantaneous output of the harmonic elimination circuit 33 at the timing of the fall of the commutation command 56. Therefore, the sampling circuit 25
The extraction timing of the instantaneous output due to is determined by the pulse width of the commutation command 56.

Therefore, in the pulse width of the commutation command 56, the end position of the pulse is located in the middle of the first current increasing region 41 and the second current increasing region 42 shown in FIG. 1B. Is set to do. That is, in the area other than the first and second current increasing areas 41 and 42, the sampling circuit 25
The pulse width of the commutation command 56 is set so that the extraction is performed by.

The reason for this is that the current value in the first current increasing region 41 depends on the difference between the voltage applied to the armature winding of the brushless motor 1 and the speed electromotive force due to the rotation of the motor, and the armature impedance. This is because the rate of increase in current is uniquely determined by the time constant of the armature impedance, not the current value and rate of increase determined by the torque generated by the motor. The current value of the second current increase region 42 is generally due to the difference between the voltage applied to the armature winding of the brushless motor 1 and the speed electromotive force due to the rotation of the motor, and the resistance component in the armature impedance. This is because the current value is fixed and hardly contributes to the torque generated by the motor.

Therefore, the first and second current increasing regions 4
An appropriate commutation timing for maintaining the generated torque according to the load cannot be determined based on the current values of 1, 42. In other words, an appropriate commutation timing can be determined based on the current value in the region other than the first and second current increasing regions 41 and 42. Therefore, the first and second current increasing regions 4
The pulse width of the commutation command 56 is set so that the sampling circuit 25 performs the extraction in regions other than 1, 42.

Specifically, the pulse of the commutation command 56 is the first
And, the shortest pulse width of the commutation command 56 is 3 to 10 times or more the LR time constant (τ) determined by the armature impedance of the brushless motor 1 so as to end in a region other than the second current increasing regions 41 and 42. Time (3τ-10τ seconds)
It is said that This is because the time output that the instantaneous output of the higher harmonic wave removing circuit 33 generally shows a saturation tendency during the sample holding operation of the sampling circuit 25 and is 95% or more of the final value is taken into consideration. The maximum pulse width of the commutation command 56 is
The time (2/3 × T seconds) is 2/3 times the commutation period (T) at the maximum rotation of the brushless motor 1. This is because the width of the second current increasing region 42 at the maximum rotation speed is set to 1/3 × T by the experiment ((1
−1/3) × T = 2/3 × T).

By the way, as described above, the variable resistance VR
The output voltage of the sample time correction circuit 39 is applied to the resistor 3 and the resistor R15 via the diode D4.

The sample time correction circuit 39 changes the pulse width of the commutation command 56 output from the commutation command circuit 29 according to the rotation speed of the brushless motor 1, and the sampling time (instantaneous output) by the sampling circuit 25 is changed. This is for correcting the extraction time of) to an appropriate timing. The sample time correction circuit 39 uses the comparator CP4.
And 1k connected to the output terminal of the comparator CP4
Ω pull-up resistor R43. The non-inverting input terminal of the comparator CP4 is connected to the output terminal of the speed detection circuit 35, and the inverting input terminal thereof is a sawtooth wave generation circuit 34.
Is connected to the output end of. In addition, the comparator CP4
Is connected to the anode of the diode D4 of the commutation command circuit 29. Therefore, as shown in FIG. 11, when the output voltage 61 of the speed detection circuit 35 is higher than the output voltage 62 of the sawtooth wave generation circuit 34, the sample time correction circuit 39 outputs a voltage of 10 V, and conversely, The output voltage 61 of the speed detection circuit 35 is the sawtooth wave generation circuit 34.
When the output voltage is lower than the output voltage 62 of 0, a voltage of 0 volt is output.

As will be described later, the speed detection circuit 35 outputs a voltage 61 according to the rotation speed of the brushless motor 1. That is, a high voltage is output when the brushless motor 1 is rotating at a high speed, and a low voltage is output when the brushless motor 1 is rotating at a low speed. On the other hand, the sawtooth wave generation circuit 34 has about 2
Sawtooth voltage 62 that changes in a constant cycle of 0 kHz
Is output. Therefore, the output voltage of the sample time correction circuit 39 becomes a rectangular wave whose duty ratio changes according to the output voltage of the speed detection circuit 35. As shown in FIG. 11, the duty ratio of the rectangular wave is equal to that of the brushless motor 1.
The higher the rotation speed of the
The lower the rotation speed of, the smaller. Therefore, the effective value of the voltage output from the sample time correction circuit 39 and applied to the variable resistors VR3 and R15 via the diode D4 changes according to the duty ratio of the rectangular wave.

The pulse width of the commutation command 56 output from the monostable multivibrator MM1 becomes shorter as the voltage value applied to the variable resistors VR3 and R15 becomes larger, and conversely becomes smaller as the voltage value applied becomes smaller. become longer.
Therefore, when the rotation speed of the brushless motor 1 becomes faster,
The duty ratio of the rectangular wave output from the sample time correction circuit 39 increases, the effective value of the voltage applied to the variable resistor VR3 increases, and the pulse width of the commutation command 56 decreases. On the contrary, when the rotation speed of the brushless motor 1 becomes slow, the duty ratio of the rectangular wave output from the sample time correction circuit 39 becomes small, the effective value of the voltage applied to the variable resistor VR3 becomes small, and the commutation becomes small. Command 56
The pulse width of is also longer. As described above, the sampling time correction circuit 39 follows the rotation speed of the brushless motor 1 to increase or decrease the pulse width of the commutation command 56, and the sampling circuit 25 automatically corrects the extraction timing of the instantaneous output to an appropriate position. It is. Therefore, the degree of freedom in the setting range of the pulse width of the commutation command 56 is increased, and the setting can be easily performed. The pulse width of the commutation command 56 is most preferably set to be 1/2 times (1 / 2T) the commutation period (T) of the brushless motor 1 at the maximum rotation speed.

The zero reset circuit 30 includes the commutation command circuit 2
For each commutation command 56 output from 9, the harmonic elimination circuit 3
It is a circuit for quasi resetting the output voltage of 3 to 0 volt, and is composed of a resistor R16 of 10 kΩ, a capacitor C6 of 180 pF, and an analog switch AS3. One end of the resistor R16 is connected to the output end of the harmonic elimination circuit 33, and the other end of the resistor R16 is connected to one end of a capacitor C6 which is grounded to form an RC low pass filter. The RC low-pass filter further removes electrostatic transfer (induction) noise and electromagnetic noise generated by the chopper control, as well as harmonic components that cannot be completely removed by the harmonic removing circuit 33.

The other end of the resistor R16, that is, the output end of the RC low pass filter is connected to the analog switch A.
It is connected to one channel terminal of S3 and one non-inverting input terminal of the comparator CP1 which is one input terminal of the commutation command circuit 29. The other channel terminal of the analog switch AS3 is grounded, and the gate of the analog switch AS3 is connected to the output terminal of the commutation command circuit 29. Therefore, when the high commutation command 56 is output from the commutation command circuit 29, the analog switch AS3 is turned on by the commutation command 56, and the commutation command circuit 29 is turned on.
The non-inverting input terminal of the comparator CP1 of
Fake reset to 0 volts.

The counting circuit 31 is composed of a hexadecimal counter CT (TC4017 and clear circuit) which is counted at each rising edge of the commutation command 56 output from the commutation command circuit 29. The output end of the commutation command circuit 29 is connected to the input end CK of the counter CT, and the counter CT
Output terminals 0 to 5 of the OR gates ORu of the distribution circuit 32.
To ORz, the output terminals 6 to 9 of the counter CT are connected to the clear terminal CLR via the diodes D5 to D8, respectively. The clear terminal CLR is connected to a noise-preventing capacitor C7 and a pull-down resistor R17 whose other end is circuit-grounded. Commutation command circuit 29
When a rising signal is input from the counter CT to the input terminal CK of the counter CT, the counter CT is output in order of the output terminal 0, the output terminal 1, ...
Outputs a high signal.

The distribution circuit 32 is a circuit for distributing and outputting the output from the counting circuit 31 to the inverter circuit 23, and is provided with six OR gates ORu to ORz and three inverters Iu to Iw. There is. Each inverter Iu ~
Iw is composed of an open collector type NPN digital transistor whose emitter terminal is grounded and has a high breakdown voltage. Note that each of the inverters Iu to Iw may be configured by an N-MOS field effect transistor whose source terminal is grounded in place of the digital transistor. Moreover, you may comprise using a photocoupler etc. as needed.

The input end of the OR gate ORu of the distribution circuit 32 is connected to the output ends 0 and 1 of the counter CT, and the output end thereof is connected to the input end of the inverter Iu. The input end of the OR gate ORv is connected to the output ends 2 and 3 of the counter CT, and the output end thereof is connected to the input end of the inverter Iv. The input terminal of the OR gate ORw is a counter C
It is connected to the output terminals 4 and 5 of T, and the output terminal thereof is connected to the input terminal of the inverter Iw. The input terminal of the OR gate ORx is connected to the output terminals 3 and 4 of the counter CT, the input terminal of the OR gate ORy is connected to the output terminals 5 and 0 of the counter CT, and the input terminal of the OR gate ORz is connected to the counter C.
It is connected to the output terminals 1 and 2 of T. Inverter Iu ~
The output ends of Iw and the OR gates ORx to ORz are connected to the resistors R1u to R1z connected to the gate terminals of the field effect transistors Qu to Qz of the inverter circuit 23. FIG. 12 shows the relationship between the input and output of the distribution circuit 32 and the three phases (U) of the brushless motor 1 corresponding to the relationship.
Phase, V phase, Z phase), the direction of current flowing in the armature winding is shown.

The speed detecting circuit 35 detects the commutation cycle of the brushless motor 1 based on the commutation command 56 output from the commutation command circuit 29, and detects the rotation speed of the brushless motor 1 from the commutation cycle. Circuit. The detected speed is converted into a voltage value and output to the speed correction circuit 37 and the sample time correction circuit 39. In the circuit, the inverted output (Q bar) of the commutation command 56 is input to the speed detection circuit 35. This considers the drive capability of the monostable multivibrator MM1 of the commutation command circuit 29.
Therefore, the output terminal Q of the monostable multivibrator MM1 may be input to the speed detection circuit 35 when there is no hindrance to the drive capability. That is, the monostable multivibrator MM2, which will be described later, may be configured to output a single pulse each time the monostable multivibrator MM1 outputs a single pulse.

The speed detection circuit 35 includes a monostable multivibrator MM2, and an input terminal A of the monostable multivibrator MM2 is connected to an output terminal Q bar of the monostable multivibrator MM1 of the commutation command circuit 29. ing. Further, one end of the monostable multivibrator MM2 is connected to the 10 volt output of the auxiliary power supply circuit 50.
A kΩ resistor R36 and a 0.1 μF capacitor C13 connected to the other end of the resistor R36 and the monostable multivibrator MM2 are connected. Further, the output terminal Q of the monostable multivibrator MM2 is connected to one end of a resistor R37 of 100 kΩ, and the other end of the resistor R37 is connected to the plus side terminal of a 10 μF electrolytic capacitor C14 whose minus side terminal is circuit grounded, It is connected to the input terminal of an operational amplifier OP12 that forms a buffer. Operational amplifier O
The output end of P12 is the output end of the speed detection circuit 35,
It is connected to the speed correction circuit 37 and the sample time correction circuit 39.

Each time the commutation command 56 falls, the output terminal Q of the monostable multivibrator MM1 of the commutation command circuit 29.
A high pulse is output from the bar (FIG. 13B), and at the rising timing thereof, a one-shot high pulse 58 is output from the output terminal Q of the monostable multivibrator MM2 of the speed detection circuit 35 (FIG. 13C). ). The high pulse 58 is generated by the resistor R37 and the capacitor C14.
Are averaged by an RC averaging circuit composed of
Appears at the connection end with.

By the way, the monostable multivibrator MM
Since the resistor R36 and the capacitor C13 connected to 2 are fixed, the width of the high pulse 58 is constant.
Further, the high pulse 58 is output for each commutation command 56.
Therefore, the shorter the generation cycle of the commutation command 56, that is, the faster the rotation speed of the brushless motor 1, the more the capacitor C1.
The voltage between the terminals of 4 becomes high (FIG. 13 (c) B), and conversely,
The longer the generation cycle of the commutation command 56, that is, the slower the rotation speed of the brushless motor 1, the lower the terminal voltage of the capacitor C14 (FIG. 13 (c) A). In this way, the rotation speed of the brushless motor 1 is detected as the voltage across the terminals of the capacitor C14.

Since the output impedance (R37) of the RC averaging circuit is relatively large, 100 kΩ, the output impedance is reduced to the speed correction circuit 37 and the sample timing correction circuit 39 via the buffer composed of the operational amplifier OP12. It is outputting. Therefore, the RC averaging calculation error in the speed detection circuit 35 does not occur,
The averaging result can be transmitted to a plurality of circuits (speed correction circuit 37 and sample time correction circuit 39).

The speed setting circuit 36 is used for the brushless motor 1
It is a circuit for starting and stopping, and for setting the rotation speed. The speed setting circuit 36 corresponds to the auxiliary power supply circuit 22 10
2.2 kΩ resistor R41 connected to the volt output, 560Ω resistor R42 grounded to the circuit, both resistors R41,
And a variable resistor VR4 of 5 kΩ connected between R42. The target voltage of the rotation speed is output from the slider end of the variable resistor VR4. That is, by changing the slider position of the variable resistor VR4, the brushless motor 1 can be started or stopped, and the rotation speed thereof can be changed.

10 kΩ is applied to the slider end of the variable resistor VR4.
A first-order delay circuit composed of a resistor R40 and a 10 μF electrolytic capacitor C16 is connected. The negative side terminal of the capacitor C16 is grounded to the circuit, and the positive side terminal is connected to the speed correction circuit 37 together with the resistor R40.

Variable resistance V for setting the target voltage of the rotation speed
When the slider position of R4 is suddenly changed by the user, the current flowing through the brushless motor 1 suddenly changes, and the commutation timing becomes unstable, and an overcurrent flows through the brushless motor 1. I will end up. However, in this speed setting circuit 36, the target voltage is output via the first-order lag circuit composed of the resistor R40 and the capacitor C16. Therefore, even in such a case, the target voltage can be gently changed. It is possible to avoid the occurrence of dots. Therefore, even when the position of the slider of the variable resistor VR4 suddenly changes, the rotational speed of the brushless motor 1 can be gradually changed to drive smoothly.

The speed correction circuit 37 compares the voltage value of the target speed set by the speed setting circuit 36 with the voltage value of the actual speed detected by the speed detection circuit 35 to determine the operation amount to be corrected by the chopper. It is for outputting to the control circuit 38. With this speed correction circuit 37, the speed setting circuit 36
It is possible to rotate the brushless motor 1 at the target speed set by.

The speed correction circuit 37 includes an operational amplifier OP13. The non-inverting input terminal of the operational amplifier OP13 is the output terminal of the speed setting circuit 36, and the inverting input terminal is the output of the speed detection circuit 35 via the resistor R38 of 5 kΩ. Connected to the ends, respectively. The inverting input terminal of the operational amplifier OP13 is connected to one end of a resistor R39 of 50 kΩ and an integrating capacitor C15 of 0.1 μF, and the other ends of these resistor R39 and capacitor C15 are connected to the output terminal of the operational amplifier OP13. Further, the output terminal of the operational amplifier OP13 is connected to the inverting input terminal of the comparator CP3 of the chopper control circuit 38 as the output terminal of the speed correction circuit 37.

Operational amplifier OP13 of the speed correction circuit 37
Together with the resistors R38 and R39 form a non-inverting amplifier for the output of the speed setting circuit 36. Operational amplifier O
The input voltage to the non-inverting input terminal of P13, that is, the output voltage of the speed setting circuit 36 is set to V ₁ , while the operational amplifier OP1
The voltage at the other end of the resistor R38 connected to the inverting input of
That is, assuming that the output voltage of the speed detection circuit 35 is V ₂ , 2
Since the resistance values of the two resistors R38 and R39 are 5 kΩ and 50 kΩ, respectively, the output voltage V _o of the operational amplifier OP13 is V _o = V ₁ + 50/5 × (V ₁ −V ₂ ) = V ₁ +10.
(V ₁ −V ₂ ).

The output voltage of the speed correction circuit 37 is output to the inverting input terminal of the comparator CP3 of the chopper control circuit 38. On the other hand, as will be described later, the comparator CP
A sawtooth wave that oscillates at a constant period is output from the sawtooth wave generation circuit 34 to the non-inverting input terminal 3. Therefore, the target voltage V ₁ of the speed setting circuit 36 is faster than the speed detection circuit 35.
If the detected voltage is higher than the detection voltage V ₂ , the chopper control circuit 3
The duty ratio of the low output of the rectangular wave output from 8 increases, the effective value of the voltage applied to the brushless motor 1 increases, and the rotation speed of the brushless motor 1 is corrected in the upward direction. On the contrary, when the target voltage V ₁ of the speed setting circuit 36 is lower than the detection voltage V ₂ of the speed detecting circuit 35, the duty ratio of the row output of the rectangular wave output from the chopper control circuit 38 becomes smaller. The effective value of the voltage applied to the brushless motor 1 is reduced, and the rotation speed of the brushless motor 1 is corrected in the downward direction.
The stability of the control system is ensured by the integrating capacitor C15.

The sawtooth wave generation circuit 34 is a circuit for generating the sawtooth wave 62 having a constant frequency (about 20 kHz in this circuit) (see FIG. 11). The generated sawtooth wave is output to the chopper control circuit 38 and the sample time correction circuit 39.

The sawtooth wave generation circuit 34 includes a comparator CP2, and the non-inverting input terminal of the comparator CP2 is connected to a resistor R19 of 100 kΩ, a resistor R20 of 220 kΩ, and an anode of a diode D9. . The other end of the resistor R20 is connected to the circuit ground and the resistor R19 is connected.
The other end of is connected to the 10 volt output of auxiliary power circuit 22. The cathode of the diode D9 has the other end connected to the 10-volt output of the auxiliary power supply circuit 22 and is 1 kΩ.
Resistor R18 and the output terminal of the comparator CP2,
It is connected to the resistor R21 of kΩ and the cathode of the diode D10. The other end of the resistor R21 and the diode D1
The anode of 0 is 180 pF with the other end grounded.
Of the capacitor C8 and the inverting input terminal of the comparator CP2. The inverting input terminal of the comparator CP2 is connected to the chopper control circuit 38 and the sample timing correction circuit 39 as the output terminal of the sawtooth wave generation circuit 34. That is, the sawtooth wave 62 of about 20 kHz applied to the inverting input terminal of the comparator CP2 is output to the chopper control circuit 38 and the sample time correction circuit 39.

The chopper control circuit 38 outputs a chopper-shaped rectangular wave to the lower arm transistor Qx of the inverter circuit 23.
Is a circuit for outputting to Qz to control the chopper of the brushless motor 1. By controlling the duty ratio of the rectangular wave output from the chopper control circuit 38, that is, by performing pulse width modulation, the brushless motor 1
The effective voltage applied to the brushless motor 1 is controlled, and the variable speed operation of the brushless motor 1 is performed.

The chopper control circuit 38 includes a comparator CP3, the non-inverting input terminal of which is connected to the output terminal of the sawtooth wave generating circuit 34, and the inverting input terminal of which is connected to the output terminal of the speed correction circuit 37. ing. The output terminal of the comparator CP3 has a pull-up resistor R25 of 1 kΩ.
Is connected to the 10-volt output of the auxiliary power supply circuit 22 via an input terminal of the chopper control circuit 38 and the input terminals of the inverters Ia and Ix to Iz, and the starting compensation circuit 2
7 is connected to the input terminal.

The chopper control circuit 38 outputs a rectangular wave of about 20 kHz, which is the same frequency as the sawtooth wave output from the sawtooth wave generation circuit 34. The duty ratio of the rectangular wave is determined by the slider position of the variable resistor VR4 of the speed setting circuit 36 and the rotation speed of the brushless motor 1 detected by the speed detection circuit 35. The higher the duty ratio of the row output of the rectangular wave is, the faster the brushless motor 1 is rotated.

Next, the operation of the brushless motor drive circuit 21 configured as described above will be described. When a DC voltage of 30 V is applied from the DC power supply 50, a stabilized voltage of 10 V is supplied from the auxiliary power supply circuit 22 to each circuit. The counting circuit 31, which receives a driving voltage of 10 V from the auxiliary power supply circuit 22, outputs from the output terminals 0 to 5, for example, “100”.
The signal “000” is output to the distribution circuit 32. Upon receiving this, the distribution circuit 32 outputs "011010" to the inverter circuit 23 as the output of "uvwxyz" (see FIG. 12). In the inverter circuit 23, the upper arm transistor Qu is turned on by the signal and the lower arm transistor Qy is turned on by the chopper control circuit 38.
It is turned on and off based on the chopper-shaped rectangular wave output from the. As a result, the armature current flows from the U phase of the armature winding of the brushless motor 1 to the V phase, and the driving of the plurality of brushless motors 1 is started. That is, the brushless motor 1
The armature current in the armature winding of the socket terminal 1 of the connector 11 from the output end R connected to the inverter circuit 23.
1b1, the pin terminal 4b1 of the connector 4, the connecting piece 4c1 and the circuit pattern 7a of the connector substrate 7,
To the coil winding 6 that constitutes the phase-phase armature winding, and from the coil winding 6 that constitutes the U-phase armature winding to the coil that constitutes the star-connected V-phase armature winding. It flows to the winding 6. It should be noted that this armature current is accompanied by a substantially triangular wave pulsation (harmonic component) that increases when the lower arm transistor Qy is on and decreases when it is off.

The armature currents flowing through the plurality of brushless motors 1 are collectively detected by the shunt resistor Rs of the current detection circuit 24, converted into voltage, and output to the harmonic elimination circuit 33. The output voltage of the current detection circuit 24 is supplied to the chopper control circuit 3 by the harmonic elimination circuit 33.
In synchronization with the output of 8, the lower arm transistor Qy of the inverter circuit 23 is stored in the capacitor C1 while being turned on. By storing the output voltage of the current detection circuit 24 in synchronization with the chopper control in this manner, the harmonic component due to the chopper control is removed. The output voltage of the current detection circuit 24 stored in the capacitor C1 is amplified by about 5.7 times and further passed through the RC low pass filter composed of the resistor R16 and the capacitor C6, and then the comparator CP1 of the commutation command circuit 29. It is output to the non-inverting input terminal of.

On the other hand, in the starting compensation circuit 27, when the duty ratio of the rectangular wave low output output from the chopper control circuit 38 reaches a predetermined value or more (for example, about 3.8% or more) (FIG. 9 (b) B). ), The output voltage of the operational amplifier OP11 is 0
Soar from 8.5 volts to about 8.5 volts (Fig. 9 (d))
B). Due to the rise of the output voltage of the operational amplifier OP11, the differentiation circuit composed of the capacitor C12 and the resistor R34 operates, and the differential pulse voltage gradually decreasing from the voltage value of less than 8.5 V is output to the priority circuit 28. (FIG. 9 (e) B).

In addition to the output of the starting compensation circuit 27, the voltage of the sampling circuit 25 amplified by the amplifier circuit 26 is also output to the priority circuit 28. However, when the commutation command has not been issued even once, the sampling circuit 2
The sample operation of 5 is not performed and the output voltage is 0 volt. Therefore, the priority circuit 28 prioritizes the output of the starting compensation circuit 27 over the output of the sampling circuit 25, and outputs the output to the inverting input terminal of the comparator CP1 of the commutation command circuit 29.

In the commutation command circuit 29, the comparator CP
1, the output voltage of the harmonic elimination circuit 33 is compared with the output voltage of the starting compensation circuit 27 output via the priority circuit 28. As a result of the comparison, the output of the commutation command 56 is on standby until the output voltage of the harmonic elimination circuit 33 becomes higher than the output voltage of the starting compensation circuit 27. This commutation command 5
While the output of No. 6 is on standby, the same phase of the armature winding (for example, U phase to V phase) is continuously energized, so that an armature sufficient to generate a starting torque for the plurality of brushless motors 1 is generated. Electric current is supplied, and the field rotors of the brushless motors 1 gradually start to rotate.

The value of the armature current of the brushless motor 1 changes with the rotation of the field. The change in the armature current value is detected by the shunt resistor Rs of the current detection circuit 24 and is stored in the harmonic elimination circuit 33 in synchronization with the output of the chopper control circuit 38. Stored current detection circuit 2
The output voltage of No. 4 is amplified approximately 5.7 times in the harmonic elimination circuit 33, and is output to the non-inverting input terminal of the comparator CP1 of the commutation command circuit 29 via the zero reset circuit 30. As a result, when the output voltage of the harmonic elimination circuit 33 becomes higher than the output voltage of the starting compensation circuit 27, the commutation command circuit 2
The high signal 55 is output from the comparator CP1 of 9
A one-shot commutation command 56 is output from the monostable multivibrator MM1 to the counting circuit 31.

The counter CT of the counting circuit 31 to which the commutation command 56 is input updates the output states of the output terminals 0 to 5 in response to the rising edge of the pulse of the commutation command 56, and the distribution circuit 32.
Output to. For example, if the output state of the output terminals 0 to 5 before the commutation command is “100000”, the commutation command 56 updates the output state to “010000” (see FIG. 12). As a result, each output of “uvwxyz” of the distribution circuit 32 becomes “011001”, and the field effect transistors Qu and Qy of the inverter circuit 23 which were turned on are replaced by
The field effect transistors Qu and Qz are turned on, and the armature current of the brushless motor 1 that has been flown from the U phase to the V phase is commutated from the U phase to the W phase.

On the other hand, the commutation command 56 output from the commutation command circuit 29 is output not only to the counting circuit 31 but also to the sampling circuit 25 and the zero reset circuit 30, and the analog switches AS2 and AS2 of both circuits 25 and 30 are output. Turn on AS3.

When the analog switch AS3 of the zero reset circuit 30 is turned on, the output voltage of the harmonic elimination circuit 33 is pseudo reset to 0 volt. This surely lowers the output voltage to the non-inverting input terminal of the comparator CP1 than the output voltage to the inverting input terminal thereof, so that the output of the comparator CP1 of the commutation command circuit 29 is switched from high to low. Produces a pulse 55 (FIG. 8)
(F)). Therefore, the monostable multivibrator MM1 of the commutation command circuit 29 that responds to the single pulse 55 has the duty ratio of the high output of the sample time correction circuit 39,
When a predetermined time determined by the variable resistor VR3, the resistor R15, and the capacitor C5 has elapsed, the output is switched from high to low, and the next commutation command 56 generation standby state is entered.

On the other hand, when the analog switch AS2 is turned on by the commutation command 56, the sampling circuit 25 is connected to the output terminal of the harmonic elimination circuit 33, and the output voltage of the harmonic elimination circuit 33 changes to the resistor R7 and the resistor R7. It is input to the capacitor C2 of the RC low-pass filter composed of the capacitor C2. When the commutation command 56 switches from high to low in this state, the analog switch AS2 is turned off, but the voltage value (instantaneous output) of the harmonic wave removing circuit 33 immediately before the turning off is stored in the capacitor C2. The stored voltage value (instantaneous output) is approximately 1.
It is amplified four times and output to the priority circuit 28. As described above, the commutation command 56 switches from high to low in the intermediate region between the first and second current increasing regions 41 and 42, so the instantaneous output of the current detection circuit 24 in that intermediate region is It is extracted by the sampling circuit 25 via the wave removing circuit 33.

By the way, as shown in FIG. 9E, the output voltage of the starting compensating circuit 27 gradually decreases from a voltage value of less than 8.5 V with a negative slope over time. . On the other hand, the output voltage of the sampling circuit 25 is
Since it is the instantaneous value of the armature current detected by the current detection circuit 24, it gradually (stepwise) rises after the brushless motor 1 is started. That is, the amplified output voltage of the sampling circuit 25 gradually and discretely rises with the passage of time after the start of energization of the armature current.

The priority circuit 28 outputs the larger one of the amplified output voltage of the sampling circuit 25 and the output voltage of the starting compensation circuit 27 to the commutation command circuit 29. Therefore, the output of the priority circuit 28 switches from the output voltage of the starting compensation circuit 27 to the amplified output voltage of the sampling circuit 25 at a certain time point. Then, after this switching, the amplified sampling circuit 25
The output voltage of is continuously output to the commutation command circuit 29 as the output voltage of the priority circuit 28 (that is, the commutation target voltage).

Comparator CP1 of commutation command circuit 29
Outputs a high signal 55 to the monostable multivibrator MM1 when the output voltage of the harmonic elimination circuit 33 via R16 becomes 1.4 times or more the output voltage of the sampling circuit 25 (FIG. 8 (f)). As a result, the commutation command circuit 29
The one-shot commutation command 56 is output from the counter to the counting circuit 31 (and the sampling circuit 25 and the zero reset circuit 30) (FIG. 8G), and the counting circuit 31 and the distribution circuit 32.
And, the commutation of the plurality of brushless motors 1 is performed by the inverter circuit 23. Then, by continuing this commutation, the plurality of brushless motors 1 are rotated.

Further, the commutation command circuit 29 outputs an inverted output (Q-bar output) of the commutation command 56 to the speed detection circuit 35 (FIG. 13). In the speed detection circuit 35, the monostable multivibrator MM2 is provided at every rising edge of the inverted output.
Outputs a one-shot high pulse 58 having a constant time width, and this high pulse 58 is averaged by the RC averaging circuit of the resistor R37 and the capacitor C14 (FIG. 1).
3 (c)). Since the high pulse 58 is output for each commutation command, the shorter the commutation cycle, that is, the brushless motor 1
The faster the rotation speed is, the higher the averaged voltage value (the voltage value between the terminals of the capacitor C14) becomes. Therefore, the averaged inter-terminal voltage of the capacitor C14 is output (feedback) to the speed correction circuit 37 and the sample time correction circuit 39 via the buffer OP12 as the actual speed information of the brushless motor 1.

To the speed correction circuit 37, in addition to the voltage value as the actual speed information output from the speed detection circuit 35,
The voltage value as the target speed information set by the speed setting circuit 36 is output. In the speed correction circuit 37, both voltage values are compared and amplified, and the amplification result is output to the chopper control circuit 38 as a manipulated variable. As described above, when the target speed voltage value is V ₁ and the actual speed voltage value is V ₂ , the speed correction circuit 37 outputs V _o = V ₁ +10 (V ₁ −V ₂ ) voltage V _o.
Is output to the inverting input terminal of the comparator CP3 of the chopper control circuit 38.

Comparator CP of chopper control circuit 38
A sawtooth wave that oscillates at a constant cycle is output from the sawtooth wave generation circuit 34 to the non-inverting input terminal 3. Therefore, the target voltage V ₁ of the speed setting circuit 36 is set to the speed detection circuit 3
5 is higher than the detected voltage V ₂ (V ₁ > V ₂ ), the duty ratio of the rectangular wave row output output from the chopper control circuit 38 is increased, and the effective voltage applied to the brushless motor 1 is increased. The value of is increased, and its rotation speed is corrected in the ascending direction. Conversely, the target voltage V of the speed setting circuit 36
_{When 1} is lower than the detection voltage V ₂ of the speed detection circuit 35 (V ₁ <V ₂ ), the duty ratio of the row output of the rectangular wave output from the chopper control circuit 38 becomes small and applied to the brushless motor 1. The effective value of the applied voltage is reduced and the rotation speed is corrected in the descending direction. In this way, the actual rotation speeds of the brushless motors 1 are fed back and corrected so as to match the target speed.

As described above, according to the brushless motor 1 of this embodiment, the pin terminals 4 connected to the three-phase armature windings are used.
A plurality of brushless motors 1 of the same model can be connected by the connector 4 including b1 to 4b6. Therefore, for example, the brushless motor drive circuit 21 sequentially applies a DC voltage to the armature windings of the three phases to cause armature currents to flow through the armature windings of the plurality of brushless motors 1, respectively. Can be rotated together. That is, a single brushless motor drive circuit 21 can rotate a plurality of brushless motors 1 together.

The connector 4 of the brushless motor 1 has six pin terminals 4b1 to 4b6.
The pin terminals 4b1 to 4b3 can be respectively connected to the output terminals R to T of the brushless motor drive circuit 21, while the pin terminals 4b4 to 4b6 are connected to the pinless terminals 4b4 to 4b6 via the above-mentioned connection cable 10 and are of the same type. 1 can be connected (see FIG. 6). Moreover, the pin terminal 4
b1 to 4b3 and the pin terminals 4b3 to 4b6 are the connection pieces 4
Circuit patterns 7 of c1 to 4c3 and the connector substrate 7
Since they are connected to the coil windings 6 forming the three-phase armature windings via a to 7c, the same DC voltage is sequentially applied to the three-phase armature windings by the brushless motor drive circuit 21. The brushless motor 1 of the model can be energized. Moreover, since it is not necessary to separately provide the brushless motor 1 with the connectors for respectively connecting the brushless motor drive circuit 21 and the brushless motor 1 of the same model,
The manufacturing cost of the brushless motor 1 as a whole can be reduced.

When the armature current of the brushless motor 1 exceeds 1.4 times the instantaneous value held by the sampling circuit 25, the commutation command 56 is output. Since the sampling circuit 25 performs the extraction in the intermediate region between the first and second current increasing regions 41 and 42, the commutation command 56 is output in the second current increasing region 42.
The commutation of the brushless motor 1 is performed in this area 42.
Therefore, the brushless motor drive circuit 21 can smoothly drive the plurality of brushless motors 1 without using a rotor magnetic pole position sensor such as a Hall element or a shaft encoder.

In particular, in the brushless motor drive circuit 21 of the present embodiment, the actual speed information of the brushless motor 1 is fed back and compared with the target speed set by the user, and the brushless motor 1 is applied according to the difference. The effective voltage is changed. Therefore, the plurality of brushless motors 1 can be constantly rotated at a speed that matches the target.

The effective voltage applied to the brushless motor 1 is changed by pulse width modulation (PWM) control, and chopper control is used to perform this pulse width modulation control. Although the chopper control is accompanied by a harmonic component, the harmonic component is not averaged and removed by a low-pass filter, but is removed by operating the harmonic elimination circuit 33 in synchronization with the chopper control. Therefore, even when the duty ratio of the chopper control is small, it is possible to detect the armature current while keeping the correct value, so that the commutation operation is performed at an appropriate timing even during low speed operation with a small duty ratio. be able to. Therefore, the plurality of brushless motors 1 can be operated at variable speeds in the entire duty ratio range of about 3.8% to 100%.

Further, since the sampling circuit 25 extracts the instantaneous output of the current detection circuit 24 for each commutation operation and performs the commutation operation based on the instantaneous value, even when the load torque suddenly changes, The commutation timing can be quickly adjusted, and an appropriate commutation operation can be performed.

Next, the brushless motor 70 of the second embodiment will be described with reference to FIG. The brushless motor 70 of the second embodiment differs from the brushless motor 1 of the first embodiment described above in that the connector member is changed. Hereinafter, the same parts as those in the first embodiment are designated by the same reference numerals, the description thereof will be omitted, and only different parts will be described.

FIG. 14A is an external perspective view of the brushless motor 70 of the second embodiment, and FIG. 14B is a vertical sectional view of the connector 71. Note that FIG. 14B shows a cross section of the connecting member 71b arranged substantially at the center of the connector 71 among the three connecting members 71b arranged in the connector 71 of FIG. 14A. .

In the brushless motor 70 of the second embodiment, a connector 71 is used in place of the connector 4 of the brushless motor 1 of the first embodiment and the connector 11 mounted on the connector 4, and a brushless motor drive circuit is used. Two
1 and the brushless motor 71 of the same model are connected.
As shown in FIG. 14A, the connector 71 includes a substantially rectangular parallelepiped housing 71 a formed of a synthetic resin having no conductivity such as ABS resin.
On the front surface of a, three circular recesses 71a1 to 71a3 are provided at substantially equal intervals. These recesses 71
A substantially cylindrical connecting member 71b is provided inside each of a1 to 71a3.
b are made of a conductive material such as tin-plated phosphor bronze and have substantially the same shape. Each connection member 71b
The concave socket terminals 71b1 are respectively provided on one end side of the housing, and the other end side thereof is formed on the rear surface of the housing 71a (the inner side of FIG.
1b2 are respectively provided in a protruding manner.

The socket terminal 71b1 of the connecting member 71b of the connector 71 is formed in conformity with the outer shape of the pin terminal 71b2 of the connector 71 of the same type, and the pin terminal 71b2 is formed so that it can be fitted. Therefore, by fitting the pin terminal 71b2 of the other connector 71 into the socket terminal 71b1 of the one connector 71, the connection member 71b of the one connector 71 and the connection member 71b of the other connector 71 can be connected to each other. it can. According to the connector 71 configured in this way, by connecting and connecting a plurality of connectors 71 of the same type, it is possible to collectively connect a plurality of brushless motor drive circuits 21 and brushless motors 1 of the same model. Of.

As shown in FIG. 14B, the connector 71 provided in the brushless motor 70 is mounted on the surface of the connector substrate 7 (upper side in FIG. 14B) and is connected to the connecting member 71b. It is connected to a circuit pattern 7b formed on the back surface (lower side of FIG. 14B) of the connector substrate 7 via a connecting piece 72 protruding from the outer periphery. Moreover, this circuit pattern 7b is connected to the coil winding 6 that constitutes the V phase of the armature winding of the brushless motor 70. Therefore, the connecting member 71b shown in FIG. 14B is connected to the coil winding 6 that constitutes the V phase of the armature winding via the connecting piece 72 and the circuit pattern 7b.
Although not shown in FIG. 14B, one of the two connecting members 71b other than the connecting member 71b connected to the coil winding 6 forming the V phase of the armature winding is connected via the circuit pattern 7a. And is connected to the coil winding 6 forming the U-phase of the armature winding, and the other side is connected to the coil winding 6 forming the W-phase of the armature winding via the circuit pattern 7c. .

As described above, according to the brushless motor 70 of the second embodiment, in the connector 71 to which the other brushless motor 70 is connected, the three connecting members 71b thereof apply the DC voltage to the three-phase armature winding. Since it is also used as an electrode terminal for connecting the brushless motor drive circuit 21 that is sequentially energized, the brushless motor drive circuit 21 and the other brushless motors 70 are connected by the one connector 71.
Can be connected together. That is, it is not necessary to separately provide connectors for connecting the brushless motor drive circuit 21 and the other brushless motors 70 to one brushless motor 70, and the manufacturing cost of the brushless motor 70 as a whole can be reduced.

Further, as described above, the connector 71 provided in the brushless motor 70 shown in FIG.
Since the connectors 71 connected thereto are of the same type, it is not necessary to separately design the connector 71 provided in the brushless motor 70 and the connector connected to the connector 71. Therefore, the manufacturing cost of the entire system including the plurality of brushless motors 70 and the brushless motor drive circuit 21 can be reduced accordingly.

The present invention has been described above based on the embodiments, but the present invention is not limited to the above embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention. Is easily guessed.

For example, in the first and second embodiments, the connectors 4 and 71 to which the brushless motor drive circuit 21 and the brushless motor 1 of the same model are connected are mounted on the connector substrate 7 fixed to the yoke 5. These connectors 4,
71 may be directly fixed to the case body 2.

In the first embodiment, the housing 4a of the connector 4 is provided with the substantially cylindrical pin terminals 4b1 to 4b6, and the protective walls 4a1 to 4a6 are provided around the pin terminals 4b1 to 4b6.
The shape of the connector 4 is not necessarily limited to this. For example, like the connector 11, a plurality of fitting holes may be recessed in the housing, and pin terminals may be provided inside the fitting holes. .

In the brushless motor drive circuit 21, the shunt resistance Rs forming the current detection circuit 24 is
It is inserted in the ground side line of the DC link and is configured to detect all three-phase armature currents with one shunt resistor Rs. However, if it is a current detection circuit that can detect the armature current, it may be provided at a position other than the ground side line of the DC link. The individual current detection circuits may be separately provided.

Further, in the brushless motor drive circuit 21, the sampling circuit 25 detects the instantaneous output of the harmonic elimination circuit 33 for each commutation command in order to quickly respond to a sudden change in the load torque. However, the present invention is not limited to this, and the instantaneous output of the harmonic elimination circuit 33 may be detected once for each of a plurality of commutation commands. In the brushless motor 1 including the three-phase armature windings as in the present embodiment, such detection may be performed once every three or six commutation commands.

In this embodiment, in order to reduce power consumption,
Lower arm transistors Qx to Q controlled by chopper
Field effect transistors were used not only for z but also for the upper arm transistors Qu to Qw. However, the upper arm transistors Qu to Q without chopper control are
Since w does not require high-speed operation, a junction type PNP transistor may be used in place of the field effect transistor in order to reduce the cost of the circuit and improve the availability of parts. Further, instead of the lower arm transistors Qx to Qz, the upper arm transistor Qu
It may be configured such that the chopper control is performed by ~ Qw. Further, the upper and lower arm transistors Qu to Qz may be chopper-controlled.

The same principle configuration as that of the present embodiment may be configured by using a combination of an A / D converter and a microcomputer or a digital signal processor, or by using a microcomputer and a software with a built-in A / D converter.

[0137]

The brushless motor according to claim 1 and
According to the brushless motor drive circuit,
The connector member of the multi-phase brushless motor
For the armature winding, the multi-phase armature of another brushless motor
The windings are connected. These brushless motors and connectors
Armature current of another brushless motor connected to the
Is at least 1 for each energized phase by the current detection circuit.
The voltage is converted into one and detected.
Based on the commutation command circuit,
Electric machine of other brushless motor connected to connector member
About the total value of the current flowing in the child winding
The arrival of the second current increasing region is detected. This second
At the timing when the current increase area of
A commutation command is output from the
The switching element of the inverter circuit is
Brushless motor and connector member turned on or off
Commutation of other brushless motors connected to
The brushless motor is rotated without a sensor. like this
The brushless motor and its connection
The brushless motors can be rotated together by passing armature currents to the other brushless motors connected to the actuator members . That is, there is an effect that a plurality of brushless motors can be collectively rotated by one brushless motor drive circuit.

According to the brushless motor of the second aspect, the brushless motor and the brushless motor of the first aspect.
In addition to the effect of the brushless motor of the motor drive circuit ,
Since the motor connection terminal of the connector member to which another brushless motor can be connected is also used as the circuit connection terminal for connecting the brushless motor drive circuit that sequentially applies DC voltage to the multi-phase armature windings. The brushless motor drive circuit and other brushless motors can be connected together from one connector member. That is, it is not necessary to separately provide a connector for connecting the brushless motor drive circuit and another brushless motor to one brushless motor, and it is possible to reduce the manufacturing cost of the entire brushless motor.

According to the brushless motor of the third aspect, the brushless motor and the brushless motor of the first aspect.
In addition to the effect of the brushless motor of the motor drive circuit ,
The connector member includes a circuit connection terminal to which a brushless motor drive circuit can be connected, and a motor connection terminal to which another brushless motor can be connected, and the motor connection terminal is a multi-phase armature winding of the brushless motor. Since it is connected to the wire, there is an effect that a DC voltage sequentially applied to the armature windings of a plurality of phases by the brushless motor drive circuit can be applied to another brushless motor through the motor connection terminal. . Moreover, since it is not necessary to separately provide a connector for connecting the brushless motor drive circuit and another brushless motor to the brushless motor,
This has the effect of reducing the manufacturing cost of the brushless motor as a whole.

According to the brushless motor of the fourth aspect , the brushless motor and the brushless motor of the first aspect.
A brushless motor for a motor drive circuit or claim 2 or
In addition to the effect of the brushless motor described in 3, the connector substrate for connecting the plural-phase armature windings and the connector member is attached to the iron core member around which the plural-phase armature windings are wound. Therefore, the connector member mounted on the connector substrate can be arranged near the plural-phase armature windings. Therefore, when connecting the armature windings of a plurality of phases and the connector member, it is not necessary to draw out the aerial wiring such as a jumper wire from the armature windings of each phase and connect them to the connector member. There is an effect that it is possible to prevent the rotation of the brushless motor from being hindered by the wiring being entangled with the rotor of the brushless motor.

[0141]

[Brief description of drawings]

FIG. 1A is a diagram showing a waveform of a current flowing in one phase of an armature winding of a brushless motor, and FIG.
It is the figure which expanded and showed one block of the current waveform of (a).

FIG. 2 is an external perspective view of a brushless motor that is an embodiment of the present invention.

FIG. 3A is an enlarged perspective view of a connector arranged in the brushless motor, and FIG. 3B is an external perspective view of a connection cable including a connector detachable from the connector arranged in the brushless motor. It is a figure.

FIG. 4 is a cross-sectional view of a brushless motor.

FIG. 5 is a partial vertical sectional view of a brushless motor.

FIG. 6 is a circuit diagram in a state where a plurality of brushless motors of the same model are connected in parallel.

FIG. 7 is a circuit diagram of a brushless motor drive circuit.

FIG. 8 is a diagram showing a relationship between output voltage waveforms of respective circuits during steady operation of the brushless motor. (A) is
It is a figure which showed the output voltage waveform of the PWM chopper control circuit, (b) is a figure which showed ON operation of each transistor of an inverter circuit, (c) showed the output voltage waveform of the current detection circuit. It is a figure, (d) is a figure which showed the output voltage waveform of a harmonic removal circuit, (e) is a figure which showed the output voltage waveform of an amplification circuit, (f) is a commutation command. It is a diagram showing an output voltage waveform of the comparator of the circuit,
(G) is a diagram showing an output voltage waveform of the commutation command circuit.

FIG. 9 is a diagram showing the relationship between the voltage division ratio of the variable resistance of the speed setting circuit and the output voltage waveform of each circuit at the start of the brushless motor. FIG. 7A is a diagram showing how the voltage dividing ratio of the variable resistance of the speed setting circuit changes. FIG.
FIG. 6 is a diagram showing an output voltage waveform of the PWM chopper control circuit in a partially enlarged manner, and (c) is a diagram showing a voltage waveform input to the operational amplifier of the starting compensation circuit,
(D) is a diagram showing an output voltage waveform of the operational amplifier of the starting compensation circuit, (e) is a diagram showing an output voltage waveform of the starting compensation circuit, and (f) is an output of the current detection circuit. It is the figure which showed the voltage waveform.

FIG. 10 is a diagram showing the relationship between the voltage division ratio of the variable resistance of the speed setting circuit and the output voltage waveform of each circuit when the brushless motor is driven to stop and when the brushless motor is stopped to start. (A) is a diagram showing how the voltage dividing ratio of the variable resistance of the speed setting circuit changes, and (b) is a diagram showing a partially enlarged output voltage waveform of the PWM chopper control circuit. , (C) is a diagram showing a voltage waveform input to the operational amplifier of the starting compensation circuit, and (d) is a diagram showing an output voltage waveform of the operational amplifier of the starting compensation circuit.
(E) is a diagram showing an output voltage waveform of the starting compensation circuit, and (f) is a diagram showing an output voltage waveform of the current detection circuit.

FIG. 11 is a diagram showing a relationship between output voltage waveforms of a speed detection circuit, a sawtooth wave generation circuit, and a sample timing correction circuit.

FIG. 12 is a diagram showing the relationship between the output of the counting circuit and the output of the distribution circuit, and the relationship between the current direction flowing in the armature winding of the brushless motor at that time.

13A is a diagram showing a voltage waveform of a Q output of a monostable multivibrator of a commutation command circuit, FIG.
(B) is a diagram showing the voltage waveform of the Q-bar output of the monostable multivibrator of the commutation command circuit, and (c) is the voltage waveform of the Q-output of the monostable multivibrator of the speed detection circuit and the capacitor C14. It is a figure showing the relation with the voltage between terminals.

FIG. 14A is an external perspective view of the brushless motor according to the second embodiment, and FIG. 14B is a vertical cross-sectional view of the connector.

[Explanation of symbols]

1,70 Brushless motor (brushless motor) 4,71 Connector (connector member) 4b1 to 4b6 Pin terminal (motor connecting terminal, circuit connecting terminal) 5 Yoke (part of iron core member) 5a Teeth (part of iron core member) ) 7 connector board 21 brushless motor drive circuit 22 auxiliary power supply circuit 23 inverter circuit 24 current detection circuit 25 sampling circuit (part of commutation command circuit) 26 amplification circuit 27 start compensation circuit 28 priority circuit 29 commutation command circuit (conversion) Part of flow command circuit, commutation command output circuit) 30 Zero reset circuit 31 Counting circuit (part of energization control circuit) 32 Distribution circuit (part of energization control circuit) 33 Harmonic elimination circuit 34 Sawtooth wave generation circuit ( Part of chopper control circuit) 35 Speed detection circuit 36 Speed setting circuit (speed changing circuit) 37 Speed correction circuit 38 Chopper control circuit (part of chopper control circuit) 39 Sample timing correction circuit 41 First increase area 42 of armature current Second increase area 50 of armature current DC power supply 52 Connection circuit 56 Commutation command 71b Connection member ( Motor connection terminal, circuit connection terminal)

Continuation of front page (51) Int.Cl. ⁷ identification code FI H02P 6/08 (56) Reference JP-A-51-41812 (JP, A) JP-A-10-14153 (JP, A) JP-A-9 -37586 (JP, A) JP-A-6-54588 (JP, A) Actually developed 62-104554 (JP, U) Actually developed 1-159606 (JP, U) (58) Fields investigated (Int.Cl) . ^7, DB name) H02K 29/00 H02K 21/00 H02K 3/50 H02K 5/22 H02P 6/04 H02P 6/06 H02P 6/08

Claims (4)

(57) [Claims] 1. A multi-phase armature winding.And itsMulti-phase power
Armature windingConnected withOther brushless motorsMultiple
Several phase armature windingConnector member that can be connected to
A brushless motor having Connected to the multi-phase armature winding of that brushless motor
Connected to the brushless motor and the connector member
Directly to the multi-phase armature windings of other brushless motors
A plurality of switching elements for sequentially energizing the flowing voltage
An inverter circuit having Turn on the multiple switching elements of the inverter circuit.
Or the brushless motor and
Another brushless motor connected to the connector member
An energization control circuit that rotates Connected to the brushless motor and the connector member
The current flowing through the armature winding of another brushless motor is
At least one for each energized phase and convert it to a voltage
A current detection circuit for detecting, Based on the voltage detected by the current detection circuit, the brush level
A brush connected to the motor and the connector member
About the total value of the current flowing through the armature winding of the less motor
By detecting the second current increasing region in the commutation cycle of 1,
Commutation command to the energization control circuit at the detected timing
The brushless motor and the connector member
Commutate the other brushless motors connected to
And a commutation command circuit
Motor and brushless motor drive circuit. 2. A connector member of the brushless motor includes a motor connection terminal formed to be connectable to another brushless motor, the motor connection terminal being connected to the plurality of phase armature windings with a direct current. The brushless motor and the brushless according to claim 1, wherein the brushless motor and the brushless motor are shared with a circuit connection terminal for connecting a brushless motor drive circuit that sequentially applies a voltage.
Brushless motor for motor drive circuit . 3. A connector member of the brushless motor is connectable to a circuit connection terminal to which a brushless motor drive circuit for sequentially applying a DC voltage to the armature windings of the plurality of phases can be connected, and to another brushless motor. The brushless according to claim 1, further comprising a motor connection terminal, the motor connection terminal being connected to the plurality of phase armature windings.
Brushless motor for motor and brushless motor drive circuit . Wherein said the core member the armature windings of a plurality of phases of the brushless motor is wound, an armature winding and prior to the plurality of phases of the brushless motor wound on the core member
While connecting the connector member of the brushless motor ,
2. A brushless motor and a brush according to claim 1, further comprising: a connector board on which the connector member is mounted, the connector board being attached to the iron core member.
A brushless motor for a ladderless motor drive circuit or claim
The brushless motor according to 2 or 3.