JPH11332199A - Brushless motor and brushless motor drive circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To permit connection of the other brushless motor by providing a connector member which can connect, on the one hand, a plurality of armature coils and on the other hand, also connect, the other brushless motor. SOLUTION: At the left side end surface of an almost cylindrically formed body 2 of a brushless motor 1, a column-type rotor shaft 3 extended toward the external side is projected to rotate, while at the right side of external circumference, a connector 4 is arranged. This connector 4 is provided for connecting a brushless motor drive circuit, and a 3-phase armature coil of the brushless motor 1 of the same type to the 3-phase armature coil of the brushless motor 1 and is also provided with an almost parallelopiped rectangular housing 4a formed of a synthetic resin having no conductivity such as an ABS resin or the like. Therefore, since the other brushless motor can be connected to the armature coil, a plurality of brushless motors can be rotated collectively with only one brushless motor drive circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 that can rotate the brushless motor and another brushless motor collectively without a sensor.

[0002]

2. Description of the Related Art Conventionally, a sensorless drive circuit of a brushless motor focuses on a correlation between a speed electromotive force generated in an armature winding of a brushless motor being rotated and a position of a field, and uses the speed electromotive force to perform a brushless motor. The commutation timing of the motor is determined, and the brushless motor is commutated in accordance with the commutation timing, whereby the brushless motor is rotationally driven without a sensor.

[0003]

The speed electromotive force is:
Since it is inevitable 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 individually detected. Can not do. For this reason, 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 driven to rotate without a sensor.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. A brushless motor to which another brushless motor can be connected, and the brushless motor and another brushless motor are collectively sensorless. It is an object of the present invention to provide a brushless motor drive circuit that can be driven to rotate.

[0005]

In order to achieve this object, a brushless motor according to claim 1 is rotated by sequentially applying a DC voltage to a multi-phase armature winding. A connector member is formed so that the armature winding of the phase is connected and another brushless motor is connectable. According to the brushless motor according to the first aspect, for example, when another brushless motor is connected to the multi-phase armature winding by the connector member and a DC voltage is sequentially applied to the multi-phase armature winding, When one brushless motor is driven (rotated), the other brushless motors are similarly driven (rotated).

According to a second aspect of the present invention, there is provided a brushless motor according to the first aspect, wherein the connector member has a motor connection terminal formed to be connectable to another brushless motor. The terminal is shared with a circuit connection terminal for connecting a brushless motor drive circuit for sequentially supplying a DC voltage to the plurality of armature windings.

According to a third aspect of the present invention, in the brushless motor according to the first aspect, the connector member is connectable to a brushless motor drive circuit that sequentially supplies a DC voltage to the plurality of armature windings. And a motor connection terminal to which another brushless motor can be connected, and the motor connection terminal is connected to the multi-phase armature winding. According to the brushless motor according to the third aspect, the brushless motor operates in the same manner as the brushless motor according to the first aspect, and the brushless motor drive circuit is connected via the circuit connection terminal of the connector member. A DC voltage is sequentially applied to the multi-phase armature windings. In addition, since the motor connection terminals of the connector member are connected to the armature windings of the plurality of phases, the brushless motor drive circuit supplies power to the other brushless motors connected via the motor connection terminals. Will be

A brushless motor according to a fourth aspect is the brushless motor according to any one of the first to third aspects, wherein an iron core member around which the plurality of phase armature windings are wound;
A connector board for connecting the plurality of armature windings wound around the core member and the connector member; and a connector board on which the connector member is mounted, and the connector board is mounted on the core member. Is being worn.

According to a fifth aspect of the present invention, there is provided a brushless motor drive circuit connected to a plurality of phase armature windings in the brushless motor according to any one of the first to fourth aspects, and a DC voltage is applied to the plurality of phase armature windings. An inverter circuit having a plurality of switching elements for sequentially energizing, an energization control circuit that turns on or off the plurality of switching elements of the inverter circuit to perform commutation, rotates the brushless motor, and the brushless motor and A current detection circuit that collectively converts currents flowing through the armature windings of the other brushless motors into a voltage and detects the voltage, and outputs a commutation command to the energization control circuit based on a detection voltage of the current detection circuit; And a commutation command circuit for commutating the brushless motor and another brushless motor, respectively.

When the brushless motor according to any one of claims 1 to 4 rotates, the positional relationship between the field of the motor and the energized armature winding changes. With this change, the value of the current flowing through the armature winding also changes. The brushless motor drive circuit according to claim 5 determines the commutation timing by focusing on the change in the armature current,
Sensorless driving of the brushless motor is enabled. Specifically, as shown in FIG. 1, when the armature winding is energized while the brushless motor is driven, the value of the current flowing through the armature winding shows a remarkable increase twice (41, 42). ). Therefore, the commutation timing is determined by detecting the second remarkable current increase region 42 (second current increase region).

That is, according to the brushless motor drive circuit of the fifth aspect, the brushless motor is connected to the inverter circuit by the armature winding and the connector member in the brushless motor according to any one of the first to fourth aspects. An armature current flows through the armature winding of another brushless motor connected to the motor while the switching element of the inverter circuit is turned on by the power supply control circuit.
The armature current of each brushless motor is collectively converted and detected by a current detection circuit, and based on the detected voltage, the commutation command circuit detects the arrival of the armature current in the second current increase region. You. At the timing when the second current increase region arrives, a commutation command is output from the commutation command circuit to the conduction control circuit, and based on the commutation command,
The switching element of the inverter circuit is turned on or off by the conduction control circuit. Thus, commutation to the brushless motor is performed, and commutation to another brushless motor is performed, so that each brushless motor is rotated without a sensor.

[0012]

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. The principle of operation 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 one embodiment of the present invention. Brushless motor 1
Uses the field of a permanent magnet as a rotor, 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 the brushless motor 1
This is for enclosing the above-described field of the permanent magnet and the three-phase armature winding, and is formed by press-molding a thin steel material.

The left end face of the case body 2 (left side in FIG. 2)
A cylindrical shaft-like rotor shaft 3 extending outward from the case body 2 is rotatably protruded, and the brushless motor 1 is attached to various devices at the outer left end of the case body 2. (Plural) rib members 2 in rectangular plate shape for
a are provided at substantially equal intervals. Each of the rib members 2a is provided with a through hole 2b for screwing the brushless motor 1 to a frame or the like of various devices, and a bolt is passed through each of the through holes 2b to form each of the rib members 2a. The brushless motor 1 can be attached and fixed to various devices by screwing the brushless to a frame or the like of various devices.

A connector 4 is provided on the right side of the outer periphery of the case 2 around which the rib members 2a are provided (right side in FIG. 2). This connector 4 is connected to the brushless motor 1
Brushless motor drive circuit 2 to be described
1 and for connecting the three-phase armature windings of the brushless motor 1 of the same model, and is provided with a substantially rectangular parallelepiped housing 4a formed of a non-conductive synthetic resin such as ABS resin. . The motors of the same model refer to motors having substantially the same speed electromotive force constant, torque constant, and inertia (moment of inertia).

FIG. 3A is an enlarged perspective view of a connector 4 provided in the brushless motor 1, and FIG.
1 is an external perspective view of a connection cable 10 provided with a connector 11 that can be attached to and detached from a connector 4 provided in a brushless motor 1. 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 device, three substantially cylindrical pin terminals 4b1-4 are provided.
b3 are protruded outward at substantially equal intervals, and three substantially cylindrical pin terminals 4b4 to 4b6 project outward at substantially equal intervals on the front left side of the housing 4a. Has been established. These pin terminals 4b1 to 4b6
Are electrode terminals 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. Is formed. Further, on the front surface of the housing 4a, around the pin terminals 4b1 to 4b6, cylindrical protective walls 4a1 to 4a are provided.
6, and a predetermined gap is formed between the inner peripheral surfaces of the protective walls 4a1 to 4a6 and the outer peripheral surfaces of the pin terminals 4b1 to 4b6.

The protection walls 4a1 to 4a6 are pin terminals 4b1
4b6 to prevent electric shock due to contact with a finger or the like, and are formed in substantially the same shape by a non-conductive synthetic resin such as an ABS resin. These protective walls 4a1 to 4a6 are formed to protrude forward from the respective pin terminals 4b1 to 4b6, and are formed respectively.
The inner diameter of 4a6 is formed smaller than the fingertip. Therefore, the protection walls 4a1 to 4a6 can prevent a finger or the like from touching any one of the pin terminals 4b1 to 4b6 to prevent electric shock.

The connection cable 10 is a cable for connecting the connector 4 of the brushless motor 1 of this embodiment to the connector 4 of the brushless motor 1 of the same model, and as shown in FIG. A pair of connectors 11 formed in a shape, and three wiring cords 12 composed of lead wires and the like for electrically connecting the pair of connectors 11.
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 has a substantially rectangular parallelepiped housing 11a, and the housing 11a is formed of a non-conductive synthetic resin such as ABS resin. Housing 11 of this connector 11
a, three circular fitting holes 11a1 to 11a3
Are formed at substantially equal intervals, and these fitting holes 11a1 to 11a3 are provided with the protection wall 4 of the connector 4 described above.
a1 to 4a3 or protective walls 4a4 to 4a6 are formed so as to be fittable. Therefore, when the connector 11 is attached (coupled) to the connector 4, these fitting holes 1
Protection walls 4a1 to 4a3 of the connector 4 are provided at 1a1 to 11a3.
Alternatively, since the protection walls 4a4 to 4a6 are fitted respectively, 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 formed in a substantially cylindrical shape from a conductive material such as tin-plated phosphor bronze are provided, respectively. These socket terminals 11b
1 to 11b3 are the pin terminals 4b1 of the connector 4 described above.
4b3 or the pin terminals 4b4 to 4b6 are formed in a substantially cylindrical shape so as to fit therein.
Alternatively, the pin terminals 4b1 to 4b3 or the pin terminals 4b
4 to 4b6. A connector 11 (FIG. 3) is connected to one end of each wiring cord 12 (the left side of FIG. 3B).
3B, the socket terminals 11b1 to 11b3 are connected to each other, and the other end of each wiring cord 12 (FIG. 3).
The socket terminals 11b1 to 11b3 of the connector 11 (right side of FIG. 3B) are connected to the right side of FIG.

The end surfaces of the socket terminals 11b1 to 11b3 are connected to the front surface of the housing 11a, that is, the fitting holes 11a.
The inner diameter of each of the fitting holes 11a1 to 11a3 is formed to be smaller than the fingertip, respectively. Therefore, such fitting holes 11a1 to 11a
Since a finger or the like is prevented from entering the a3, it is possible to prevent the finger or the like from touching 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.
On the inner peripheral surface of the yoke 5, six teeth 5a extending toward the center of the case body 2 are protruded at substantially equal intervals. These teeth 5a are made of a magnetic material such as soft iron and have substantially the same shape, and a coil winding made of a magnet wire or the like is provided between the inner end of the teeth 5a and the end of the case body 2 side. The wires 6 are each wound. As described above, in the brushless motor 1 of the present embodiment, the six coil windings 6 wound around the six teeth 5a of the yoke 5 respectively.
Are connected in a star (Y) connection, so that three phases (U phase, V
, W-phase) armature windings.

A substantially C-shaped thin connector board 7 is fixed to the yoke 5 by screwing. The connector board 7 is a well-known circuit printed board, and the connector 4 described above is mounted on a 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 opposite to the protruding surfaces of the protective walls 4a1 to 4a3,
Similarly to the pin terminals 4b1 to 4b6 described above, three connection 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 a pin terminal 4b1.
And the connection piece 4c
2 is fixed to the pin terminal 4b2 and the pin terminal 4b5, respectively, and the connection piece 4c3 is fixed to the pin terminal 4b3 and the pin terminal 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 having the above configuration is mounted, and one end of each of the circuit patterns 7a to 7c. The connection pieces 4c1 to 4c3 of the connector 4 are connected to the sides by soldering or the like. On the other hand, coil windings 6 constituting the U, V and W phases of the armature windings are connected to the other ends of the circuit patterns 7a to 7c by soldering or the like. That is, the coil winding 6 constituting the U phase of the armature winding of the brushless motor 1 is connected to the pin terminals 4b1 and 4b4 via the circuit pattern 7a and the connection piece 4c1, respectively, and the V phase of the armature winding is Coil winding 6 constituting
Are connected to the pin terminals 4b2 and 4b5 via the circuit pattern 7b and the connection piece 4c2, respectively, and the coil winding 6 constituting the W phase of the armature winding is connected via the circuit pattern 7c and the connection piece 4c3. They are connected to the pin terminals 4b3 and 4b6, respectively.

As described above, the coil windings 6 constituting 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 board 7, respectively. It is not necessary to connect the coil windings 6 constituting the three-phase armature windings and the pin terminals 4b1 to 4b6 of the connector 4 by aerial wiring such as lead wires. Therefore, it is possible to prevent the aerial wiring from being entangled with the rotor 8 described later and hindering the rotation of the rotor 8. Moreover, since the connector board 7 is fixed to the yoke 5 by screws, the connector board 7
Can be disposed in the brushless motor 1 without rattling the connector 4 mounted on the motor.

Inside the yoke 5 to which the connector board 7 is fixed and inside the six teeth 5a, a rotor 8 pivotally supported in the front-rear direction in FIG. The rotor shaft 3 is driven into the center of the rotor 8. A pair of well-known radial bearings 8a are provided at both ends of the rotor shaft 3 in the axial direction (perpendicular to the plane of FIG. 4). It is pivoted. In FIG. 4, the rotor shaft 3 of the pair of radial bearings 8a is
Only the radial bearing 8a that supports the rear end portion of FIG.

An annular rotor core 8b made of a magnetic material such as soft iron is fitted around the outer periphery of the rotor shaft 3 supported by the pair of radial bearings 8a. On the outer peripheral surface of the rotor core 8b, four magnet members 8c curved and fitted to the curved surface are adhered, and these magnet members 8c are each formed of a known permanent magnet. Of these magnet members 8c, the adjacent magnet members 8c are magnetized to different polarities on the outer peripheral surface side. For example, the upper right part of the rotor core 8b (FIG. 4)
When the outer peripheral surface side of the magnet member 8c bonded to the upper right of the magnet member 8 is magnetized to the positive electrode (positive 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 a negative electrode (negative pole or south pole). That is, the outer peripheral surface of the magnet member 8c bonded to the lower right portion (lower right of FIG. 4) of the rotor core 8b and the outer peripheral surface of the magnet member 8c bonded to the upper left portion (upper left of FIG. 4) of the rotor core 8b. The surface side is magnetized to a negative electrode (negative pole or south pole). On the other hand, in such a case,
The outer peripheral surface side of the magnet member 8c bonded to the lower left part (lower left part of FIG. 4) of the rotor core 8b is a positive electrode (positive pole or N pole).
Is magnetized. As described above, in the brushless motor 1 of the present embodiment, a four-pole field is formed by the rotor 8 having the four magnet members 8c bonded to the rotor core 8b.

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

Next, a method of connecting the connector 4 of the brushless motor 1 configured as described above will be described with reference to FIG. FIG. 6 shows a brushless motor 1 of the same model.
FIG. 3 is a circuit diagram in a 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 (a plurality of) 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 connected to the three-phase armature windings of the brushless motor 1, respectively. These output terminals R to T have three leads. Via the wires, they are connected to the socket terminals 11b1 to 11b3 of the connector 11 of the same type as the connector 11 described above, respectively. Socket terminals 11b to 11b of this connector 11
3, pin terminals 4b1 to 4b3 of a connector 4 of the brushless motor 1 (upper side in FIG. 6) are connected to the three terminals of the brushless motor 1 described above. (See FIG. 4).

The pin terminals 4b1 to 4b3 of the connector 4 of the brushless motor 1 have pin terminals 4b4 to 4b6
Are connected respectively, and these pin terminals 4b4 to
The socket terminals 11b1 to 11b3 of the connection cable 10 described above are connected to 4b6. One ends of three wiring cords 12 are connected to the socket terminals 11b1 to 11b3 of the connection cable 10, respectively, and the socket terminals 11b1 to 11b3 respectively connected to the other ends of the three wiring cords 12 are The pin terminals 4b1 to 4b3 of the connector 4 of the brushless motor 1 of the same model (lower side in FIG. 6) are connected respectively. As described above, according to the brushless motor 1 of the present 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. In the figure, a connection cable 10 for connecting a plurality of brushless motors 1 and a brushless motor drive circuit 21 are provided. Connector 11 for connecting to brushless motor 1
Are omitted from the figure. The brushless motor drive circuit 21 performs variable speed operation of a small PM brushless motor for an indoor fan, a transport device capable of suddenly changing load torque, and a brushless motor for an outdoor fan of an air conditioner that is easily affected by a gust or the like. Used as a sensorless drive circuit. In addition, a motor with a slip ring using an armature winding as a rotor with a field as a stator, a brushless motor of an embedded magnet type, and an outer rotor motor having a stator inside and a rotor outside. This brushless motor drive circuit 21 can be used.

The brushless motor drive circuit 21 includes:
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 connector 11 through three lead wires. Five brushless motors 1 of the same model are connected in parallel to the socket terminals 11b to 11b3 of the connector 11 via the connector 4 described above. The brushless motors 1 connected to one brushless motor drive circuit 21 must be the same type of brushless motor 1. Brushless motor 1 can be connected. The number of brushless motors 1 that can be connected is determined by (maximum output current of inverter circuit 23) / (maximum current of brushless motor 1).

The auxiliary power supply circuit 22 of the brushless motor drive circuit 21 is connected to a stable 1-volt
This is a circuit that generates and outputs a voltage of 0 volt. The 10-volt voltage generated by the auxiliary power supply circuit 22 is supplied as a drive voltage to each circuit such as the start-up compensation circuit 27 and the commutation command circuit 29.

The inverter circuit 23 is a circuit for sequentially switching a 30-volt DC voltage to three-phase (U-phase, V-phase, W-phase) armature windings of a plurality (five) of brushless motors 1. It is. The plus side input terminal P of the DC power supply 50 of the inverter circuit 23 has 3
P-MOS field effect transistors Qu, Qv, Qw
Are 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 three-phase armature windings.

The upper arm transistors Qu to Qw have their gate terminals connected to the respective outputs u to w of the distribution circuit 32 via resistors Ru1 to Rw1 of 10 kΩ, respectively. It is configured to be turned on and off (see FIG. 8B). A 47 kΩ resistor R for protecting and preventing floating of the gate voltage is provided between the gates and sources of the upper arm transistors Qu to Qw.
u2 to Rw2 and the upper arm transistors Qu to Qw corresponding to the lower arm transistors Qx to Qz when the lower arm transistors Qx to Qz are turned on by chopper control.
Is a short-circuit preventing capacitor (100) for preventing the lower arm transistors Qx to Qz from turning on simultaneously.
0pF) Cu to Cw are respectively connected.

On the other hand, the gate terminals of the lower arm transistors Qx to Qz are connected to the respective outputs x to z of the distribution circuit 32 via 1 kΩ resistors Rx1 to Rz1, and are connected to inverters Ix to Iz as chopper drivers. It is connected to the output terminal of the chopper control circuit 38 via the terminal. Each of the inverters Ix to Iz is composed of an open collector NPN digital transistor whose emitter terminal is connected to the ground-side input terminal N of the DC power supply 50 (that is, the circuit is grounded). Therefore, the lower arm transistors Qx to Qz are turned on and off according to the outputs x to z of the distribution circuit 32 and the output of the chopper control circuit 38. More 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. 8A and 8B,
The lower arm transistors Qx to Qz are chopper-controlled according to the output of the chopper control circuit 38.

Note that 5.6 kΩ resistors Rx2 to Rz2 for protection and prevention of gate voltage floating are connected between the gates and sources of the lower arm transistors Qx to Qz, respectively. In addition, each arm transistor Qu
Between the source and the drain of each of the arm transistors Qu to Qz, the freewheel diodes Du to return the current caused by the back electromotive force generated in the armature winding of the plurality of brushless motors 1 when the arm transistors Qu to Qz are turned on and off. Dz
Are connected in antiparallel, respectively.

The current detection circuit 24 collects the currents flowing through the armature windings of the plurality (five) of the 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 supply 5
It is composed of a 0.1Ω (2 W) shunt resistor Rs inserted between the ground-side input terminal N and the inverter circuit 23. All three-phase armature currents of the five brushless motors 1 are converted by the shunt resistor Rs except for the return currents to the freewheel diodes Du to Dz. FIG. 8C illustrates an output voltage waveform of the current detection circuit 24 during the normal operation of the brushless motor 1.

The harmonic elimination circuit 33 synchronizes with the chopper control by the chopper control circuit 38,
3 is a circuit for storing the output voltage of the current detection circuit 24 while the lower arm transistors Qx to Qz are on, and outputting the output voltage to the sampling circuit 25 and the commutation command circuit 29. That is, the output voltage of the current detection circuit 24 is output to the sampling circuit 25 and the commutation command circuit 29 after removing the harmonic component by the chopper control. The harmonic elimination circuit 33 includes an analog switch AS1, a capacitor C1, a resistor R3 functioning as an RC low-pass filter together with the capacitor C1, and a non-inverting amplifier including resistors R4, R5 and an operational amplifier OP1.

One channel terminal of the analog switch AS1 is connected to a current detection circuit 24 via a 550Ω resistor R3.
The other channel terminal is connected to a 0.1 μF capacitor C1 whose one end is grounded. Further, the gate of the analog switch AS1 is connected to the output terminal of the chopper control circuit 38 via the inverter Ia, and while the row signal is being output from the chopper control circuit 38 (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
ＺQz is stored in the capacitor C1 in synchronization with the ON operation. Therefore, in combination with the RC low-pass filter constituted by the resistor R3 and the capacitor C1, the output voltage of the current detection circuit 24 from which higher harmonic components have been removed by the chopper control can be stored in 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 1 kΩ pull-up resistor R6. .

The non-ground terminal of the capacitor C1 is connected to the non-inverting input terminal of the operational amplifier OP1. The operational amplifier OP1 forms 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 by about 5.7 times by the non-inverting amplifiers OP1, R4 and R5, and its output terminal is Is output to the commutation command circuit 29 via the sampling circuit 25 and R16 connected to the circuit. That is, after the output voltage of the current detection circuit 24 is subjected to the removal of the harmonic components by the harmonic removal circuit 33,
The signal is amplified by a factor of about 5.7 and the sampling circuit 25 and R
16 to the commutation command circuit 29. FIG.
(D) shows the output voltage of the harmonic elimination circuit 33.

The non-inverting amplifiers OP1, R4, 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 0 times 1Ω, the output voltage of the current detection circuit 24 also becomes 1
It is multiplied by zero. 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, a resistor Rs having a small resistance value is used in order to suppress a temperature rise of the shunt resistor 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 is connected through a 1 kΩ resistor R7 to one end of which is connected to a circuit of 0.1 μF.
, And a resistor R8 of 1 MΩ. The gate of the analog switch AS2 is connected to the output terminal 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)). AS2 is turned on.

The capacitor C2 is connected to the analog switch AS
2 is connected to the output terminal of the harmonic elimination circuit 33 via the resistor R7 while the switch 2 is on. This capacitor C2 is connected to a resistor R7
Together with an RC low-pass filter to remove harmonic components that cannot be completely removed by the harmonic removal circuit 33,
The output voltage of the harmonic elimination circuit 33 is stored. The non-ground terminal of the capacitor C2 is connected only 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 as large as 1 MΩ, the voltage value of the capacitor C2 is
Is held for a predetermined time even after the switch is turned off. Therefore, the capacitor C
2, the voltage value (instantaneous output) of the harmonic elimination circuit 33 immediately before the analog switch AS2 is turned off is stored.

The commutation command 56 is, as described later,
When the output voltage of the harmonic elimination circuit 33 via R16 becomes higher than the output voltage of the sampling circuit 25 amplified by the amplification circuit 26, the output is output from the commutation command circuit 29. For this reason, if for some reason a large voltage value is held in the capacitor C2 of the sampling circuit 25, the output voltage of the harmonic elimination circuit 33 cannot be higher than the amplified output voltage of the sampling circuit 25,
The commutation command 56 cannot be generated, and the brushless motor 1
Stops.

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 but slightly discharged by the resistor R8. The voltage value of C2 also gradually decreases. Therefore, the resistance R
8 is connected in parallel to the capacitor C2, the commutation command 56 can always be regenerated 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 determined by the value of the capacitor C2.
And the lower limit 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 about 2 Hz, a time constant slightly larger than the cycle of 12 Hz which is six times as large is set, and the resistance is set so as to be in a range of about 0.1 second. The resistance value of R8 and the capacitance of 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 1 MΩ.

Depending on the type of the operational amplifier OP2 of the amplifier circuit 26, a leakage current (input bias current) may flow from the non-inverting input terminal to ground. In such a case, the voltage value of the capacitor C2 rises due to the leakage current, that is, the stored commutation target voltage which is the voltage value of the harmonic elimination circuit 33 changes in the rising direction. This makes it impossible to perform a normal commutation operation. However, by connecting the resistor R8 in parallel with the capacitor C2, such a leakage current can flow through the resistor R8, so that an increase in the voltage value of the capacitor C2 can be prevented, and the voltage value of the capacitor C2 always decreases. Therefore, the output voltage of the harmonic elimination circuit 33 can be maintained in the capacitor C2.

The amplification circuit 26 is a circuit that amplifies the voltage value stored by the sampling circuit 25 and outputs the amplified voltage value to the priority circuit 28. The amplifier circuit 26 includes an operational amplifier OP2
And a non-inverting amplifier constituted by two resistors R9 and R10 of 10 kΩ, and a variable resistor VR1 of 100 kΩ for reducing the output of the non-inverting amplifier to 1 or less, and sliding the variable resistor VR1. The commutation target voltage during steady operation is output from the slave end.

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

The resistance values of the two resistors R9 and R10 of the non-inverting amplifier are both the same 10 kΩ. Therefore, the output of the sampling circuit 25 is the non-inverting amplifier OP
2, R9 and R10 amplify approximately twice. The output of the sampling circuit 25, which has been amplified twice, is connected to the variable resistor VR.
1 is reduced to 1 or less by the variable resistor VR1 and output to the priority circuit 28. In the present embodiment, the output of the sampling circuit 25 that has been amplified twice 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 is amplified by a factor of 1.4. FIG. 8E illustrates an output voltage waveform of the amplifier circuit 26.

It should be noted that the variable resistor VR1
By adjusting the position of the slider, the amplification factor of the entire amplification circuit 26 can be changed, so that the amplification factor can be changed in accordance with the use situation. That is, tuning can be performed to maximize the motor efficiency in the normal operation region of the brushless motor 1.

The starting compensation circuit 27 includes a 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 this embodiment, the duty ratio of the row output is about 3.8. % To about 3.8%
In this 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. Note that the above-mentioned duty ratio of about 3.8% corresponds to the resistances R32 (390Ω) and R33 (10k
Ω).

The starting compensation circuit 27 includes a chopper control circuit 3
8 is provided with a resistor R31 of 100 kΩ connected to the output terminal, 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 non-inverting input terminal of the operational amplifier OP11 is connected to the auxiliary power supply circuit 22.
390Ω resistor R32 connected to the 10 volt output of
And a resistor R33 of 10 kΩ whose one end is grounded to the circuit. The output terminal of the operational amplifier OP11 is
It is connected to the anode of the diode D11 and the plus side terminal of a 10 μF electrolytic capacitor C12. 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 connected to a circuit grounded 100 kΩ resistor R34,
It is connected to the cathode of a diode D12 whose anode is grounded and one end of a variable resistor VR2 of 500 kΩ. 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 a diode D3, which is the input terminal of the priority circuit 28, as the output terminal of the starting compensation circuit 27. I have.

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

In this state, the voltage dividing 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.
% (B in FIG. 9B), the starting compensation circuit 27
Discharge of the capacitor C11 cannot follow the charge,
The input voltage to the inverting input terminal of the operational amplifier OP11 is about 9.
It drops to 62 volts or less (FIG. 9 (c) B). as a result,
The input voltage to the non-inverting input terminal of the operational amplifier OP11 is higher than the input voltage to the inverting input terminal, and the operational amplifier OP11
The output voltage of No. 11 rises from 0 volts to about 8.5 volts (FIG. 9D). Here, about 8.5 volts is a limit value of the output voltage determined by the characteristics of the operational amplifier (the operational amplifier can output only up to 1.5 volts of the power supply voltage or less due to the characteristics. Is 10 volts, because 10 volts-1.5 volts = 8.5 volts. The value of 1.5 volts naturally depends on the type of the operational amplifier.)

The output voltage of the operational amplifier OP11 is about 8.5
When the voltage reaches volts, a voltage of about 8.5 volts is applied to a differentiating circuit composed of the capacitor C12 and the resistor R34. Therefore, the starting compensating circuit 27 outputs the variable resistor VR2
And a voltage pulse in the form of a differentiated pulse that gradually decreases with the passage of time from a voltage value of slightly less than 8.5 volts, which is obtained by subtracting the voltage drop, 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 of the resistor R34 is 100 kΩ, this voltage wave is generated after one 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
7 is used as a commutation target voltage as a commutation command circuit 29.
Output to Therefore, since the commutation target voltage at the time of starting the brushless motor 1 is set high, at the time of starting the plurality of brushless motors 1, an armature current sufficient to generate a starting torque flows (FIG. 9 (f) B). ), The plurality of brushless motors 1 are started accurately.

On the other hand, if the voltage dividing ratio of the variable resistor VR4 of the speed setting circuit 36 is reduced during the rotation of the brushless motor 1 (FIG. 10A), the brushless brushless motor 1 The effective value of the voltage applied to the motor 1 also decreases, and the brushless motor 1 is decelerated. Then, when the duty ratio of the row output of the chopper control circuit 38 falls below about 3.8% (FIG. 10B), the capacitor C3 of the starting compensation circuit 27
Charging cannot follow the discharging, and the operational amplifier OP1
1 rises to 9.62 volts or more, which is the input voltage to the non-inverting input terminal of FIG.
(C)), the output voltage of the operational amplifier OP11 drops from about 8.5 volts to 0 volt (FIG. 10 (d)). When the output voltage of the operational amplifier OP11 becomes 0 volt, the charge stored in the capacitor C12 is rapidly discharged via the diode D12 and the operational amplifier OP11, and returns to the initial state.

From this state, the voltage dividing ratio of the variable resistor VR4 of the speed setting circuit 36 is increased again (FIG. 10 (a)).
When the duty ratio of the row output of the chopper control circuit 38 becomes about 3.8% or more (FIG. 10B), the operational amplifier O
The input voltage to the inverting input terminal of P11 drops 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, until the discharged capacitor C12 is recharged, a differential pulse-like voltage wave is output again from the starting compensation circuit 27 (FIG. 10 (e)).

When the DC power supply 50 is turned off during the operation of the brushless motor 1, the charge stored in the capacitor C12 is rapidly discharged through the diodes D11 and D12, and returns to the initial state. Therefore, even when the DC power supply 50 is turned on immediately after the power is turned off, the start-up compensation circuit 27 is normally operated and the brushless motor 1 is turned on.
Can be started smoothly.

As described above, in the starting compensation circuit 27 of the present embodiment, even if the voltage dividing 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 a low speed. , Then the variable resistor VR
By increasing the voltage dividing ratio of 4, the start compensation circuit 27 can output a commutation target voltage sufficient for starting the plurality of brushless motors 1. Therefore, even in such a case, the plurality of brushless motors 1 can be started accurately. Thus, the start 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 during the steady operation, 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 constituted by the diode D3. The diode D3 has an anode connected to the output terminal of the starting compensation circuit 27, a cathode connected to the output terminal of the amplifier circuit 26, and the inverting input terminal of the comparator CP1 which is one input terminal of the commutation command circuit 29. Have been. Therefore, the priority circuit 28 outputs the larger output voltage of the amplifier 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 provided for the brushless motor 1
Of the commutation command 56 of the counter circuit 31 and the sampling circuit 2
5 and a circuit for outputting to the zero reset circuit 30. The circuit mainly includes 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. The output terminal of the comparator CP1 is a monostable multivibrator MM.
1, the output terminal Q of the monostable multivibrator MM1 which issues a commutation command is connected to the input terminal CK of the counting circuit 31, the gates of both the analog switches AS2 and AS3 of the sampling circuit 25 and the zero reset circuit 30. It is connected to the.

The commutation command circuit 29 is provided with a diode D4
The anode of the diode D4 is connected to the output terminal of the sample timing correction circuit 39, and the cathode is connected to one end of a 100 kΩ variable resistor VR3. The other end of the variable resistor VR3 is connected to a resistor R1 of 10 kΩ.
5 is connected to one end of the resistor R15.
One end of the capacitor C5 and the monostable multivibrator M
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
By 1, the magnitude of the output voltage of the harmonic elimination circuit 33 is compared with the magnitude of 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 higher than the output voltage of the priority circuit 28, as shown in FIG. Output to input terminal A. As a result, 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, as shown in FIG. In addition,
The commutation command 56 is also output to the gates of the analog switches AS2 and AS3 of the sampling circuit 25 and the zero reset circuit 30 at the same time.
2. Turn on AS3.

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 is
Since the switch 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 when the commutation command 56 falls. Therefore, the sampling circuit 25
Is determined by the pulse width of the commutation command 56.

For this reason, the pulse width of the commutation command 56 is such that the end position of the pulse is located between the first current increasing region 41 and the second current increasing region 42 shown in FIG. Is set to That is, the sampling circuit 25 is located in an area other than the first and second current increasing areas 41 and 42.
The pulse width of the commutation command 56 is set so that the extraction is performed.

The reason for this is that the current value of 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, in particular, the current increase rate is uniquely determined by the time constant of the armature impedance, not the current value and the increase rate determined by the generated torque of the motor. The current value of the second current increasing region 42 is substantially determined by 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 hardly contributes to the generated torque of the motor.

Therefore, the first and second current increasing regions 4
It is not possible to determine an appropriate commutation timing for maintaining the generated torque according to the load based on the current values of 1, 42. In other words, an appropriate commutation timing can be determined based on current values in regions 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 extraction in an area other than 1 and 42.

Specifically, the pulse of the commutation command 56 is the first
And the end of the commutation command 56 in a region other than the second current increasing regions 41 and 42, the shortest pulse width is at least 3 to 10 times the LR time constant (τ) determined by the armature impedance of the brushless motor 1. Time (3τ to 10τ seconds)
It is said. At the time of the sample holding operation of the sampling circuit 25, the instantaneous output of the harmonic elimination circuit 33 generally shows a tendency to saturate, and a time margin of 95% or more of the final value is considered. The longest pulse width of the commutation command 56 is
It is set to a time (２ / 3 × T seconds) which is ／ times the commutation period (T) at the time of the highest speed rotation of the brushless motor 1. This is because the width of the second current increasing region 42 at the time of the highest rotation was set to ３ × T by an experiment ((1
−1/3) × T = 2/3 × T).

Incidentally, as described above, the variable resistor VR
The output voltage of the sampling timing correction circuit 39 is applied to the resistor 3 and the resistor R15 via the diode D4.

The sampling timing correction circuit 39 changes the pulse width of the commutation command 56 output from the commutation command circuit 29 in accordance with the rotation speed of the brushless motor 1, and changes the sampling timing (instantaneous output) of the sampling circuit 25. (Extraction time) is corrected to an appropriate timing. The sample timing correction circuit 39 includes a 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 detecting circuit 35, and the inverting input terminal is connected to the sawtooth wave generating circuit 34.
Connected to the output end of the Further, 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, a voltage of 10 volts is output from the sampling time correction circuit 39, and conversely, The output voltage 61 of the speed detection circuit 35 is set to the sawtooth wave generation circuit 34.
Is lower than the output voltage 62, a voltage of 0 volt is output.

As will be described later, the speed detection circuit 35 outputs a voltage 61 corresponding 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
Sawtooth-shaped voltage 62 that changes at a constant cycle of 0 kHz
Is output. Therefore, the output voltage of the sample timing correction circuit 39 is 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
The higher the rotation speed of the brushless motor 1
It becomes smaller as the rotation speed becomes slower. Therefore, the effective value of the voltage output from the sampling timing correction circuit 39 and applied to the variable resistor VR3 and the resistor 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 decreases as the voltage value applied to the variable resistors VR3 and R15 increases, and conversely, decreases as the applied voltage value decreases. become longer.
Therefore, when the rotation speed of the brushless motor 1 increases,
The duty ratio of the rectangular wave output from the sample timing 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. Conversely, when the rotation speed of the brushless motor 1 decreases, the duty ratio of the rectangular wave output from the sampling timing correction circuit 39 decreases, and the effective value of the voltage applied to the variable resistor VR3 decreases, resulting in commutation. Command 56
Becomes longer. In this way, 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 timing of the instantaneous output by the sampling circuit 25 is automatically corrected to an appropriate position. Because Therefore, the degree of freedom of the setting range of the pulse width of the commutation command 56 is increased, and the setting can be easily performed. It is most preferable that the pulse width of the commutation command 56 be set to be 倍 times (１ ／ T) of the commutation period (T) when the brushless motor 1 rotates at the highest speed.

The zero reset circuit 30 includes a commutation command circuit 2
9 for each commutation command 56 output from the
3 is a circuit for artificially resetting the output voltage at 0 to 0 volts, and includes 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 terminal of the harmonic elimination circuit 33, and the other end of the resistor R16 is connected to one end of a capacitor C6 that is grounded to form an RC low-pass filter. With this RC low-pass filter, in addition to electrostatic transfer (induction) noise and electromagnetic noise generated due to chopper control, harmonic components that cannot be completely removed by the harmonic removing circuit 33 are further removed.

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 a 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 is grounded,
Fake reset to 0 volts.

The counting circuit 31 is constituted by a hexadecimal counter CT (TC4017 and clear circuit) which is counted each time the commutation command 56 output from the commutation command circuit 29 rises. The output terminal of the commutation command circuit 29 is connected to the input terminal CK of the counter CT.
Output terminals 0-5 of each 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 diodes D5 to D8, respectively. The clear terminal CLR is connected to a capacitor C7 for noise prevention and a pull-down resistor R17 whose other end is grounded. Commutation command circuit 29
, A rising signal is input to the input terminal CK of the counter CT, 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 includes six OR gates ORu to ORz and three inverters Iu to Iw. I have. Each inverter Iu ~
Iw is constituted by an open collector type NPN type digital transistor whose emitter terminal is grounded to a circuit, and has a high withstand 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. Further, if necessary, a configuration using a photocoupler or the like may be employed.

The input terminal of the OR gate ORu of the distribution circuit 32 is connected to the output terminals 0 and 1 of the counter CT, and the output terminal is connected to the input terminal of the inverter Iu. The input terminal of the OR gate ORv is connected to the output terminals 2 and 3 of the counter CT, and the output terminal is connected to the input terminal 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 its output terminal 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 terminals of Iw and the OR gates ORx to ORz are connected to 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 input / output relationship of the distribution circuit 32 and the three phases (U) of the brushless motor 1 corresponding to the input / output relationship.
3 shows the directions of the currents flowing through the armature windings (phase, V-phase, and Z-phase).

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 timing correction circuit 39. In the circuit, an inverted output (Q bar) of the commutation command 56 is input to the speed detection circuit 35. This is in consideration of the drive capability of the monostable multivibrator MM1 of the commutation command circuit 29.
Therefore, when there is no hindrance to the drive capability, the output terminal Q of the monostable multivibrator MM1 may be input to the speed detection circuit 35. That is, the monostable multivibrator MM2 described later may be configured to output a single pulse for each single pulse output operation of the monostable multivibrator MM1.

The speed detecting circuit 35 has a monostable multivibrator MM2. The input terminal A of the monostable multivibrator MM2 is connected to the output terminal Q bar of the monostable multivibrator MM1 of the commutation command circuit 29. ing. The monostable multivibrator MM2 has one end connected to the 10-volt output of the auxiliary power supply circuit 22.
A resistor R36 of kΩ, 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 terminal of a 10 μF electrolytic capacitor C14 having a minus terminal grounded. It is connected to the input terminal of an operational amplifier OP12 forming a buffer. Operational amplifier O
The output terminal of P12 serves as the output terminal of the speed detection circuit 35,
The speed correction circuit 37 and the sample timing correction circuit 39 are connected.

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 a one-shot high pulse 58 is output from the output terminal Q of the monostable multivibrator MM2 of the speed detection circuit 35 at the rising timing (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 a resistor R37 and a capacitor C14.
Appears at the connection end.

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.
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 higher the rotation speed of the brushless motor 1, the more the capacitor C1
4 becomes higher (FIG. 13 (c) B), and conversely,
The longer the generation cycle of the commutation command 56, that is, the lower the rotation speed of the brushless motor 1, the lower the voltage between the terminals of the capacitor C14 (FIG. 13 (c) A). Thus, the rotation speed of the brushless motor 1 is detected as a voltage between terminals of the capacitor C14.

Since the output impedance (R37) of the RC averaging circuit is relatively large at 100 kΩ, the output impedance is reduced via the buffer constituted by the operational amplifier OP12, and the output impedance is reduced to the speed correction circuit 37 and the sample timing correction circuit 39. Output. Therefore, without causing an RC averaging calculation error in the speed detection circuit 35,
The averaging result can be transmitted to a plurality of circuits (the speed correction circuit 37 and the sample timing correction circuit 39).

The speed setting circuit 36 includes a brushless motor 1
And a circuit for setting the rotation speed. The speed setting circuit 36 is connected to the 10
A 2.2 kΩ resistor R41 connected to the volt output, a 560Ω resistor R42 grounded to the circuit, and both resistors R41,
And a variable resistor VR4 of 5 kΩ connected between R42. A target voltage of the rotation speed is output from a slider end of the variable resistor VR4. That is, by changing the position of the slider of the variable resistor VR4, the brushless motor 1 can be started or stopped, and further its rotation speed can be changed.

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

Variable resistance V for setting target voltage of rotation speed
If the slider position of R4 is suddenly changed by the user, the current flowing through the brushless motor 1 changes abruptly, causing problems such as unstable commutation timing and an overcurrent flowing through the brushless motor 1. I will. However, in the speed setting circuit 36, the target voltage is output through a first-order lag circuit constituted by the resistor R40 and the capacitor C16. The occurrence of points can be avoided. Therefore, even when the position of the slider of the variable resistor VR4 changes abruptly, the rotation speed of the brushless motor 1 can be gradually changed and the brushless motor 1 can be driven 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, and determines the amount of operation to be corrected by the chopper. This is for outputting to the control circuit 38. The speed setting circuit 36 is provided by the speed correction circuit 37.
The brushless motor 1 can be rotated at the target speed set in the above.

The speed correction circuit 37 has an operational amplifier OP13. The non-inverting input terminal of the operational amplifier OP13 is connected to the output terminal of the speed setting circuit 36, and the inverting input terminal of the operational amplifier OP13 is connected to the output of the speed detecting circuit 35 via a resistor R38 of 5 kΩ. Each end is connected. The inverting input terminal of the operational amplifier OP13 is connected to a resistor R39 of 50 kΩ and one end of an integrating capacitor C15 of 0.1 μF, and the other ends of the resistor R39 and the 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.

The operational amplifier OP13 of the speed correction circuit 37
Constitutes a non-inverting amplifier for the output of the speed setting circuit 36 together with the resistors R38 and R39. Operational amplifier O
Input voltage to the noninverting input of P13, i.e., the output voltage of the speed setting circuit 36 and V _1, whereas, the operational amplifier OP1
3, the voltage at the other end of the resistor R38 connected to the inverting input
That is, assuming that the output voltage of the speed detection circuit 35 is V ₂ , 2
Since One of the resistors R38, the resistance value of R39 is respectively 5kΩ and 50kohm, 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 described later, the comparator CP
The sawtooth wave generating circuit 34 outputs a sawtooth wave oscillating at a constant period to the non-inverting input terminal 3. Therefore, the target voltage V ₁ of the speed setting circuit 36 is higher than the speed detecting circuit 35.
Is higher than the detection voltage V ₂ , the chopper control circuit 3
The duty ratio of the row output of the rectangular wave output from 8 increases, the effective value of the voltage applied to the brushless motor 1 increases, and the rotational speed of the brushless motor 1 is corrected in the upward direction. Conversely, when the target voltage V ₁ of the speed setting circuit 36 is lower than the detection voltage V ₂ of the speed detection circuit 35, the duty ratio of the row output of the rectangular wave output from the chopper control circuit 38 decreases. Thus, the effective value of the voltage applied to the brushless motor 1 decreases, and the rotation speed of the brushless motor 1 is corrected in the downward direction.
The stability of the control system is achieved by the integration capacitor C15.

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

The sawtooth wave generating circuit 34 includes a comparator CP2. A 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 grounded, and the resistor R19
Is connected to the 10 volt output of the auxiliary power supply circuit 22. The other end of the cathode of the diode D9 is connected to a 10 kΩ output of the auxiliary power supply circuit 22 by 1 kΩ.
, The output terminal of the comparator CP2,
The resistor R21 of kΩ is connected to the cathode of the diode D10. The other end of the resistor R21 and the diode D1
0 is 180 pF with the other end grounded.
And the inverting input terminal of the comparator CP2. An inverting input terminal of the comparator CP2 is connected to a chopper control circuit 38 and a sample timing correction circuit 39 as an 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 timing correction circuit 39.

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

The chopper control circuit 38 has a comparator CP3. The non-inverting input terminal is connected to the output terminal of the sawtooth wave generating circuit 34, and the inverting input terminal is connected to the output terminal of the speed correction circuit 37. ing. The output terminal of the comparator CP3 is a 1 kΩ pull-up resistor R25.
And the output terminals of the chopper control circuit 38, the input terminals of the inverters Ia, Ix to Iz, and the starting compensation circuit 2
7 is connected to the input terminal.

From the chopper control circuit 38, a rectangular wave of about 20 kHz, which is the same as the frequency of the sawtooth wave output from the sawtooth wave generating circuit 34, is output. The duty ratio of this rectangular wave is determined by the position of the slider 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. As the duty ratio of the rectangular wave row output increases, the brushless motor 1 rotates at a higher speed.

Next, the operation of the brushless motor drive circuit 21 configured as described above will be described. When a DC voltage of 30 volts is applied from the DC power supply 50, a stabilized voltage of 10 volts is supplied from the auxiliary power supply circuit 22 to each circuit. The counting circuit 31 receiving the driving voltage of 10 volts from the auxiliary power supply circuit 22 outputs, for example, “100” from the output terminals 0 to 5.
000 "is output to the distribution circuit 32. Upon receiving this, the distribution circuit 32 outputs “011010” to the inverter circuit 23 as an output of “uvwxyz” (see FIG. 12). In the inverter circuit 23, the upper arm transistor Qu is turned on by this 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-like rectangular wave output from. As a result, an armature current flows from the U-phase to the V-phase of the armature winding of the brushless motor 1, and the driving of the plurality of brushless motors 1 is started. That is, the brushless motor 1
The armature current flows through the armature winding from the output terminal R connected to the inverter circuit 23 to the socket terminal 1 of the connector 11.
1b1, the pin terminal 4b1 of the connector 4, the connection piece 4c1, and the circuit pattern 7a of the connector board 7,
To the coil winding 6 forming the phase armature winding, and from the coil winding 6 forming the U-phase armature winding to the coil forming the star-connected V-phase armature winding. It flows to the winding 6. The armature current is accompanied by a substantially triangular pulsation (harmonic component) that increases when the lower arm transistor Qy is on and decreases when the lower arm transistor Qy 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 a 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 No. 8, the data is stored in the capacitor C1 while the lower arm transistor Qy of the inverter circuit 23 is turned on. Thus, by storing the output voltage of the current detection circuit 24 in synchronization with the chopper control, harmonic components due to the chopper control are removed. The output voltage of the current detection circuit 24 stored in the capacitor C1 is amplified by a factor of about 5.7, and further passed through an RC low-pass filter including a resistor R16 and a capacitor C6. Is output to the non-inverting input terminal.

On the other hand, in the starting compensation circuit 27, when the duty ratio of the row output of the rectangular wave output from the chopper control circuit 38 reaches a predetermined value or more (for example, about 3.8% or more) (FIG. 9B). ), The output voltage of the operational amplifier OP11 is 0
It rises sharply from a bolt to about 8.5 volts (Fig. 9 (d)).
B). Due to the rise of the output voltage of the operational amplifier OP11, a differentiating circuit constituted by the capacitor C12 and the resistor R34 operates, and a differential pulse-like voltage gradually falling from a voltage value of slightly less than 8.5 volts is output to the priority circuit 28. (FIG. 9 (e) B).

To the priority circuit 28, 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. However, in the state where the commutation command has not yet been issued, the sampling circuit 2
The sample operation of No. 5 is not performed, and the output voltage is 0 volt. Therefore, the output of the starting compensation circuit 27 is given priority over the output of the sampling circuit 25 by the priority circuit 28, and is 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
By 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
6, the energization to the same phase (for example, U-phase to V-phase) of the armature winding is continued, so that a sufficient armature for generating the starting torque to the plurality of brushless motors 1 is provided. The current is supplied, and the field rotors of the plurality of brushless motors 1 gradually start rotating.

As the field rotates, the value of the armature current of the brushless motor 1 changes. 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 by a factor of about 5.7 in the harmonic elimination circuit 33 and 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
9 outputs a high signal 55 from the comparator CP1.
The one-shot commutation command 56 is output to the counting circuit 31 from the monostable multivibrator MM1.

The counter CT of the counting circuit 31 to which the commutation command 56 is input updates the output state of the output terminals 0 to 5 in response to the rise of the pulse of the commutation command 56, and
Output to For example, if the output state of the output terminals 0 to 5 before the commutation command is “100000”, the output state is updated to “010000” by the commutation command 56 (see FIG. 12). As a result, each output of “uvwxyz” of the distribution circuit 32 becomes “011001”, and instead of the field-effect transistors Qu and Qy of the inverter circuit 23 that were turned on,
The field effect transistors Qu and Qz are turned on, and the armature current of the brushless motor 1 flowing from the U phase to the V phase is diverted 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 virtually reset to 0 volt. This ensures that the output voltage of the comparator CP1 to the non-inverting input terminal is made lower than the output voltage to the inverting input terminal thereof. A pulse 55 is generated (FIG. 8)
(F)). Therefore, the monostable multivibrator MM1 of the commutation command circuit 29 that responds to the single pulse 55 generates the high output duty ratio of the sample timing correction circuit 39,
After a lapse of a predetermined time determined by the variable resistor VR3, the resistor R15, and the capacitor C5, the output is switched from high to low, and the process shifts to a state of waiting for the next commutation command 56.

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. 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 from this state, the analog switch AS2 is turned off. The voltage value (instantaneous output) of the harmonic elimination circuit 33 immediately before the turning off is stored in the capacitor C2. The stored voltage value (instantaneous output) is approximately 1.
The signal is amplified four times and output to the priority circuit 28. As described above, the commutation command 56 is switched from high to low in the intermediate region between the first and second current increasing regions 41 and 42, so that the instantaneous output of the current detection circuit 24 in the intermediate region is higher. The signal is extracted by the sampling circuit 25 via the wave removing circuit 33.

As shown in FIG. 9 (e) B, the output voltage of the starting compensation circuit 27 gradually decreases with a lapse of time from a voltage value of slightly less than 8.5 volts with a negative gradient. . On the other hand, the output voltage of the sampling circuit 25 is
Since the current value is the instantaneous value of the armature current detected by the current detection circuit 24, the current gradually increases (stepwise) after the start of the brushless motor 1. That is, the amplified output voltage of the sampling circuit 25 gradually increases discretely with the elapse of time after the start of the passage 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 start 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 point in time. After this switching, the amplified sampling circuit 25
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
Outputs a one-shot commutation command 56 to the counting circuit 31 (and the sampling circuit 25 and the zero reset circuit 30) (FIG. 8 (g)), and the counting circuit 31 and the distribution circuit 32.
The commutation of the plurality of brushless motors 1 is performed by the inverter circuit 23. Then, by continuing the commutation, the plurality of brushless motors 1 are rotated.

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, each time the inverted output rises, the monostable multivibrator MM2
Outputs a one-shot high pulse 58 having a fixed time width, and the 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 higher the rotation speed of is, the higher the averaged voltage value (the voltage value between the terminals of the capacitor C14). Therefore, the averaged voltage between the terminals of the capacitor C14 is output (feedback) to the speed correction circuit 37 and the sample timing correction circuit 39 via the buffer OP12 as 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,
A voltage value as target speed information set by the speed setting circuit 36 is output. The speed correction circuit 37 compares and amplifies the two voltage values, and outputs the amplified result to the chopper control circuit 38 as an operation amount. As described above, V ₁ the voltage value of the target speed, when the voltage value of the actual speed is V _2, from the speed correction circuit 37, V _o = V ₁ +10 voltage V _o of (V ₁ -V ₂₎
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 oscillating at a constant period is output from the sawtooth wave generating circuit 34 to the non-inverting input terminal of No. 3. Therefore, the target voltage V ₁ of the speed setting circuit 36 is
When 5 higher than the detection voltage V ₂ of (V _1> V _2), the chopper control circuit 38 increases the duty ratio of the low output of the rectangular wave output from the effective voltage applied to the brushless motor 1 Is increased, and the rotation speed is corrected in the upward 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 is applied to the brushless motor 1. The effective value of the applied voltage is reduced, and its rotational speed is corrected in the downward direction. As described above, the actual rotation speeds of the plurality of 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 the present embodiment, the pin terminals 4 connected to the three-phase armature windings are used.
By the connector 4 provided with b1 to 4b6, a plurality of brushless motors 1 of the same model can be connected. Therefore, for example, by sequentially applying a DC voltage to the three-phase armature windings by the brushless motor drive circuit 21, the armature currents flow through the armature windings of the plurality of brushless motors 1. Can be rotated together. That is, a plurality of brushless motors 1 can be rotated collectively by one brushless motor drive circuit 21.

The connector 4 of the brushless motor 1 has six pin terminals 4b1 to 4b6.
The pin terminals 4b1 to 4b3 can be connected to the output terminals R to T of the brushless motor drive circuit 21, respectively, while the pin terminals 4b4 to 4b6 are connected to the same type of brushless motor via the connection cable 10 described above. 1 can be connected (see FIG. 6). Moreover, the pin terminal 4
b1 to 4b3 and the pin terminals 4b3 to 4b6
c1 to 4c3 and circuit pattern 7 of connector board 7
a to 7c are connected to the coil winding 6 constituting the three-phase armature winding, so that the DC voltage sequentially supplied to the three-phase armature winding by the brushless motor drive circuit 21 is the same. Electric power can be supplied to the brushless motor 1 of the model. In addition, there is no need to separately provide the brushless motor 1 with connectors for 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 becomes 1.4 times or more the instantaneous value held by the sampling circuit 25, a commutation command 56 is output. Since the extraction by the sampling circuit 25 is performed in a 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,
In this area 42, the commutation of the brushless motor 1 is performed.
Therefore, the brushless motor drive circuit 21 can drive the plurality of brushless motors 1 smoothly 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 this embodiment, the actual speed information of the brushless motor 1 is fed back, compared with the target speed set by the user, and applied to the brushless motor 1 according to the difference. The effective voltage is changed. Therefore, the plurality of brushless motors 1 can be constantly rotated at a speed matching 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 the pulse width modulation control. Although harmonic components are involved in the chopper control, the harmonic components are not removed by averaging with a low-pass filter, but are removed by operating the harmonic removing circuit 33 in synchronization with the chopper control. Therefore, even when the duty ratio of the chopper control is small, the detection can be performed while maintaining the armature current at a correct value. be able to. Therefore, the plurality of brushless motors 1 can be operated at a variable speed in the entire range where the duty ratio is about 3.8% to 100%.

Further, the instantaneous output of the current detection circuit 24 is extracted by the sampling circuit 25 for each commutation operation, and the commutation operation is performed based on the instantaneous value. The commutation timing is quickly adjusted, and an appropriate commutation operation can be performed.

Next, a brushless motor 70 according to a 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 in that the connector member is changed. Hereinafter, the same portions as those of the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. Only different portions will be described.

FIG. 14A is an external perspective view of the brushless motor 70 of the second embodiment, and FIG. 14B is a longitudinal sectional view of the connector 71. Note that FIG. 14B illustrates a cross section of the connection member 71b disposed substantially at the center of the connector 71 among the three connection members 71b disposed on the connector 71 of FIG. 14A. .

The brushless motor 70 of the second embodiment uses a connector 71 instead of the connector 4 of the brushless motor 1 of the first embodiment and the connector 11 mounted on the connector 4 to use a brushless motor driving circuit. 2
1 and a brushless motor 71 of the same model.
As shown in FIG. 14A, the connector 71 includes a substantially rectangular parallelepiped housing 71a formed of a non-conductive synthetic resin such as an ABS resin.
On the front surface of a, three circular concave portions 71a1 to 71a3 are respectively provided at substantially equal intervals. These recesses 71
Almost a cylindrical connection member 71b is disposed inside each of the three connection members 71a1 to 71a3.
b is made of a conductive material such as tin-plated phosphor bronze and is formed in substantially the same shape. Each connecting member 71b
A concave socket terminal 71b1 is provided on one end of the housing 71a, and a convex pin terminal 7 protruding from the rear surface of the housing 71a (rear side in FIG. 14A) is provided on the other end.
1b2 are each provided in a protruding manner.

The socket terminal 71b1 of the connection member 71b of the connector 71 is formed so as to conform to the outer shape of the pin terminal 71b2 of the same type of connector 71, and the pin terminal 71b2 is formed so as to be fittable. Therefore, by fitting the pin terminal 71b2 of the other connector 71 to the socket terminal 71b1 of the one connector 71, the connection member 71b of the one connector 71 can be connected to the connection member 71b of the other connector 71, respectively. it can. According to the connector 71 configured as described above, by connecting and connecting a plurality of connectors 71 of the same type, a plurality of brushless motor drive circuits 21 and a plurality of brushless motors 1 of the same model can be collectively connected. It is.

As shown in FIG. 14 (b), the connector 71 provided on the brushless motor 70 is mounted on the surface of the connector board 7 (upper side of FIG. 14 (b)). 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 connection piece 72 projecting from the outer periphery. Moreover, the circuit pattern 7b is connected to the coil winding 6 constituting the V phase of the armature winding of the brushless motor 70. Therefore, the connection member 71b shown in FIG. 14B is connected to the coil winding 6 constituting the V phase of the armature winding via the connection piece 72 and the circuit pattern 7b.
Although not shown in FIG. 14B, one of the two connection members 71b except for the connection member 71b connected to the coil winding 6 constituting the V phase of the armature winding is connected via the circuit pattern 7a. Is connected to the coil winding 6 forming the U-phase of the armature winding, and the other 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, the connector 71 to which the other brushless motor 70 is connected has three connecting members 71b which apply a DC voltage to the three-phase armature winding. Since the brushless motor drive circuit 21 and the other brushless motor 70 are commonly used as electrode terminals for connecting the brushless motor drive circuit 21 that is sequentially energized, the single connector 71 is used.
Can be connected together. That is, it is not necessary to separately provide a connector for connecting the brushless motor drive circuit 21 and another brushless motor 70 to one brushless motor 70, and the manufacturing cost of the brushless motor 70 as a whole can be reduced.

As described above, the connector 71 provided in the brushless motor 70 shown in FIG.
Since the connectors 71 connected to the connector 71 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. Accordingly, 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 based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention. Can easily be inferred.

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 board 7 fixed to the yoke 5. These connectors 4,
71 may be directly fixed to the case body 2.

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

In the brushless motor drive circuit 21, the shunt resistance Rs constituting the current detection circuit 24 is
The shunt resistor Rs is inserted into the ground line of the DC link to detect armature currents of all three phases. However, if the current detection circuit can detect the armature current, it may be provided at a position other than the ground line of the DC link, or the three-phase armature current may be individually detected. The current detection circuits may be separately provided.

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 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 winding as in the present embodiment, such detection may be performed once every three or six commutation instructions.

In this embodiment, in order to reduce power consumption,
Lower arm transistors Qx to Q for which chopper control is performed
A field effect transistor was used not only for z but also for the upper arm transistors Qu to Qw. However, upper arm transistors Qu-Q in which chopper control is not performed
Since high-speed operation is not required for w, a junction PNP transistor may be used instead of a field-effect transistor in order to reduce the cost of the circuit and improve the availability of parts. Also, instead of the lower arm transistors Qx to Qz, the upper arm transistor Qu
... Qw may be configured to perform chopper control. Further, the chopper control may be performed by both the upper and lower arm transistors Qu to Qz.

A principle configuration similar to 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 having an A / D converter and software.

[0137]

According to the brushless motor of the first aspect, another brushless motor can be connected to the armature winding by the connector member connected to the multi-phase armature winding. Therefore, for example, by sequentially applying a DC voltage to the multi-phase armature windings by the brushless motor drive circuit, armature currents are respectively supplied to the brushless motor and the other brushless motors, and the brushless motors are rotated collectively. be able to. That is, there is an effect that a plurality of brushless motors can be rotated collectively by one brushless motor drive circuit.

According to the brushless motor of the second aspect, in addition to the effects of the brushless motor of the first aspect, the motor connection terminal of the connector member to which another brushless motor can be connected has a multi-phase armature winding. Since it is shared with a circuit connection terminal for connecting a brushless motor drive circuit that sequentially supplies a DC voltage to the wire, the brushless motor drive circuit and another brushless motor can be collectively connected from one connector member. . That is, 1
There is no need to separately provide a connector for connecting the brushless motor drive circuit and another brushless motor to the brushless motor described above, so that the manufacturing cost of the brushless motor as a whole can be reduced.

According to the brushless motor of the third aspect, in addition to the effects of the brushless motor of the first aspect, the connector member includes a circuit connection terminal to which a brushless motor drive circuit can be connected and another brushless motor. And a motor connection terminal connectable to the motor, and the motor connection terminal is connected to a plurality of armature windings of the brushless motor. Thus, the DC voltage sequentially applied to the armature winding of the first motor can be applied to another brushless motor. In addition, 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, it is possible to reduce the manufacturing cost of the brushless motor as a whole.

According to the brushless motor of the fourth aspect, in addition to the effects of the brushless motor according to any one of the first to third aspects, a connector board for connecting a plurality of armature windings and a connector member is provided. Is attached to the core member on which the multi-phase armature winding is wound, so that the connector member mounted on the connector board can be arranged near the multi-phase armature winding. . Therefore, when connecting the armature winding of a plurality of phases and the connector member, it is not necessary to draw out an aerial wiring such as a jumper wire from the armature winding of each phase and connect it to the connector member. There is an effect that it is possible to prevent that the wiring is entangled with the rotor of the brushless motor or the like and hinders the rotation of the brushless motor.

According to the brushless motor drive circuit of the present invention, the current detection circuit converts the armature currents of the brushless motor and the other brushless motors according to any one of claims 1 to 4 into a voltage. The commutation command circuit detects the arrival of the armature current in the second current increase region based on the detected voltage, and outputs the commutation command at the timing of the arrival of the second current increase region. The commutation of the brushless motor and another brushless motor is performed. Therefore, according to such a brushless motor drive circuit, there is an effect that a plurality of brushless motors can be rotated without a sensor.

[Brief description of the drawings]

FIG. 1A is a diagram showing a current waveform flowing in one phase of an armature winding of a brushless motor, and FIG.
FIG. 4 is an enlarged view of one block of the current waveform of FIG.

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

FIG. 3A is an enlarged perspective view of a connector provided on the brushless motor, and FIG. 3B is an external perspective view of a connection cable provided with a connector detachable from the connector provided on the brushless motor. FIG.

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

FIG. 5 is a partial longitudinal 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 each circuit during a steady operation of the brushless motor. (A)
It is a figure showing an output voltage waveform of a PWM chopper control circuit, (b) is a figure showing ON operation of each transistor of an inverter circuit, and (c) was showing an output voltage waveform of a current detection circuit. FIG. 3D is a diagram illustrating an output voltage waveform of a harmonic elimination circuit, FIG. 4E is a diagram illustrating an output voltage waveform of an amplifier circuit, and FIG. FIG. 3 is a diagram showing an output voltage waveform of a comparator of the circuit;
(G) is a figure showing the output voltage waveform of the commutation command circuit.

FIG. 9 is a diagram showing a relationship between a voltage dividing ratio of a variable resistor of a speed setting circuit at the time of starting the brushless motor and an output voltage waveform of each circuit. (A) is a figure which shows the mode of change of the voltage division ratio of the variable resistor of a speed setting circuit, (b)
FIG. 3 is a diagram showing a partially enlarged output voltage waveform of a PWM chopper control circuit, and FIG. 3C is a diagram showing a voltage waveform input to an operational amplifier of a start compensation circuit;
(D) is a diagram showing an output voltage waveform of the operational amplifier of the start compensation circuit, (e) is a diagram showing an output voltage waveform of the start compensation circuit, and (f) is an output of the current detection circuit. FIG. 3 is a diagram showing a voltage waveform.

FIG. 10 is a diagram showing a relationship between a voltage dividing ratio of a variable resistor of a speed setting circuit and an output voltage waveform of each circuit when the brushless motor is driven from a stop to a stop and from a stop to a start. (A) is a diagram showing a state of a change in the voltage dividing ratio of the variable resistor of the speed setting circuit, 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, (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 illustrating a relationship between an output of a counting circuit and an output of a distribution circuit, and a relationship of a direction of a current flowing through an armature winding of the brushless motor at that time.

FIG. 13A is a diagram showing a voltage waveform of a Q output of a monostable multivibrator of a commutation command circuit;
(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. FIG. 5 is a diagram showing a relationship between the terminal voltage and the terminal voltage.

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

[Explanation of symbols]

1,70 Brushless motor (brushless motor) 4,71 Connector (connector member) 4b1-4b6 Pin terminal (motor connection terminal, circuit connection 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 Amplifier circuit 27 Start-up compensation circuit 28 Priority circuit 29 Commutation command circuit (Commutation circuit) Part of flow command circuit, commutation command output circuit) 30 zero reset circuit 31 counting circuit (part of conduction control circuit) 32 distribution circuit (part of conduction control circuit) 33 harmonic removal circuit 34 sawtooth wave generation circuit ( Part of chopper control circuit) 35 Speed detection circuit 36 Speed setting circuit (speed change circuit) 37 Speed correction Path 38 Chopper control circuit (part of chopper control circuit) 39 Sample timing correction circuit 41 First increase area of armature current 42 Second increase area of armature current 50 DC power supply 52 Connection circuit 56 Commutation command 71b Connection Components (motor connection terminals, circuit connection terminals)

Continued on the front page (51) Int.Cl. ⁶ identification code FI H02P 6/08

Claims (5)

[Claims] 1. A brushless motor which is rotated by sequentially applying a DC voltage to a plurality of armature windings, wherein said plurality of armature windings are connected, and another brushless motor is connectable. A brushless motor comprising a formed connector member. 2. The motor according to claim 1, wherein the connector member includes a motor connection terminal formed so as to be connectable to another brushless motor, and the motor connection terminal sequentially applies a DC voltage to the plurality of phase armature windings. 2. The brushless motor according to claim 1, wherein the brushless motor is shared with a circuit connection terminal for connecting a brushless motor drive circuit to be energized. 3. The motor according to claim 1, wherein the connector member is a circuit connection terminal to which a brushless motor drive circuit for sequentially supplying a DC voltage to the plurality of armature windings can be connected, and a motor connection to which another brushless motor can be connected. The brushless motor according to claim 1, further comprising a terminal, wherein the motor connection terminal is connected to the plurality of armature windings. 4. An iron core member on which the plurality of phase armature windings are wound, and the plurality of phase armature windings and the connector member wound on the iron core member are connected. The brushless motor according to any one of claims 1 to 3, further comprising a connector board to be mounted, wherein the connector board is attached to the iron core member. 5. A brushless motor according to claim 1, which is connected to a multi-phase armature winding.
An inverter circuit having a plurality of switching elements for sequentially supplying a DC voltage to the plurality of armature windings;
A commutation control circuit for turning on or off a plurality of switching elements of the inverter circuit to perform commutation and rotate the brushless motor, and a current flowing through the armature windings of the brushless motor and another brushless motor collectively to form a voltage. And a commutation command circuit for outputting a commutation command to the energization control circuit based on a detection voltage of the current detection circuit and commutating the brushless motor and another brushless motor, respectively. And a brushless motor drive circuit comprising: