JPH09149676A - Brushless motor driver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the deterioration of the performance of a motor by a method wherein an offset signal which cancels a phase shift is generated in accordance with a rotor position detection signal and supplied to a position signal generating means. SOLUTION: Differential amplifiers 81a and 81b amplify position detection signals (e1 and e2 ) and (e3 and e4 ) which correspond to the rotation positions of a rotor 2 and whose phases are opposite to each other and, further, correct position detection signals which are distorted by the influences of magnetic fields generated by an armature coil 6 in accordance with offset signals (nf and ng) supplied from a timing correcting means 82. That is, rotor position signals (E12 and E21 ) and (E34 and E43 ) which have phases same as the position detection signals (e1 and e2 ) and (e3 and e4 ) and have a phase difference in an electrical angle of (π/2) corresponding to correct detected positions between each other are generated. The offset values of input offsets are so predetermined as to cancel error voltages which are generated in Hall devices HG1 and HG2 by disturbance magnetic fields (f and g).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor driving device applied to a VTR cylinder motor, a capstan motor, or the like.

[0002]

2. Description of the Related Art A conventional brushless motor driving device will be described below by taking a four-phase brushless motor as an example.
FIG. 4 is a structural diagram of a four-phase brushless motor, FIG. 5 is a schematic configuration diagram of a conventional brushless motor driving device, and FIG. 6 is a timing diagram of the conventional brushless motor driving device.

In FIG. 4, a four-phase brushless motor 1
00 is a permanent magnet 10 with 14 poles on the outer periphery of the rotor 102.
3 is fixed, the armature coil 106 (L1, L2, L3, L4) is wound around each of the 12 stator cores 105, and each is delta-connected to form a four-phase stator 1.
04 and a rotor position detecting means 107 having two Hall elements for detecting the rotational position of the rotor 102 are respectively arranged on the motor board 110 to form main mechanical elements.

(L1 and L2) and (L3 and L4) of the armature coil 106 have a phase difference of {(π / 2) + nπ} radian (n = 0, ± 1, ± 2, ...) In electrical angle. Of the armature coil 106 (L1 and L3) and (L2 and L).
4) is an electrical angle of approximately (π + nπ) radians (n = 0, ±
, ± 2, ...).

In the Hall element which constitutes the rotor position detecting means 107, the phase difference of the output signals is {(π / 2) + nπ} radians (n = 0, ± 1, ± 2, radians) in terms of electrical angle.
Are arranged so as to have a phase difference of.

A drive unit 108 for generating a conduction control signal for controlling the excitation current of the armature coil 106 based on the position detection signal corresponding to the detected rotational position, and an excitation current for the armature coil 106 based on the conduction control signal. The brushless motor 100 is configured as a whole by arranging the drive output means 109 for generating the above on the motor substrate 110.

In FIG. 5, in each rotor position detecting means 107, the magnetic pole of the rotor 102 is the rotor position detecting means 1
07, position detection signals (e ₁ ,
e ₂ ) and (e ₃ , e ₄ ) are generated and provided to the position signal generating means 108a. Position detection signals (e ₁ , e ₂ )
The phases of and (e ₃ , e ₄ ) are π with respect to each other, as shown in FIG.
Has a phase difference of / 2.

The driving device 108 includes a position signal generating means 108a composed of two sets of differential amplifiers corresponding to each rotor position detecting means 107 and a conduction control means 108b composed of two sets of differential distributors. Rotor position detection means 107
Position detection signals (e ₁ , e ₂ ) and (e ₃ ,
e ₄ ) based on the conduction control signals (i ₁ , i ₂ ), (i ₃ , i
₄ ) is generated and provided to the drive output means 109.

The conduction control signals (i ₁ , i ₂ ) are rectangular waves having mutually opposite phases, and similarly, the conduction control signals (i 3, i ₂ ).
4) is also a rectangular wave of opposite phase, and the conduction control signals (i ₁ , i ₃ ) and (i ₂ , i ₄ ) are respectively π / 2.
Has a phase difference of.

The drive output means 109 is provided with two sets of power amplifiers each having a source side and a sink side as a pair of power transistors, and the respective terminals of the source and the sink are four delta-connected armature coils 106 (L).
1, L2, L3, L4) and a conduction control signal (i ₁ , supplied from the conduction control means 108b).
i ₂ ) and (i ₃ , i ₄ ) are used to sequentially drive the power transistors forming a pair on the source side and the sink side by a signal pair combining them to supply an exciting current to the armature coil 106. .

With these configurations, the position detection signals (e ₁ , e ₂ , e ₃ ,
The exciting current is controlled based on e ₄ ) and the armature coil 10
There is known a brushless motor driving device configured to apply a rotational driving force to the rotor 102 according to a magnetic field generated by the rotor 6.

[0012]

In the conventional brushless motor driving device, since the rotor position detecting means 107 is composed of a Hall element, not only is it affected by the magnetic field of the permanent magnet 103, but also the armature coil 106. The position detection signals (e ₁ , e ₂ , e ₃ , e ₄ ) provided by the Hall element are distorted as shown in FIG. 6 because they are also affected by the magnetic field generated depending on the direction and current value of the excitation current of At (ed ₁ , e
The waveform is d ₂ , ed ₃ , ed ₄ ).

The position signal generation means 108a and the conduction control means 108b receive the position detection signal (ed
_{Since 1} , ed ₂ , ed ₃ , ed ₄ ) are processed at the timings (ed ₁ = ed ₂ ) and (ed ₃ = ed ₄ ), as shown in FIG. i
_{1, i 2, i 3,} i 4) only from time t shifted conduction control signal _{(id 1, id 2, id} 3, id 4) for generating a.

The power transistors having a source side and a sink side forming the drive output means 109 as a pair have conduction control signals (id ₁ , id ₂ ) and (i) including phase shift.
to be sequentially switched d _3, id _4), which is the original switching point when correctly positioned detect the position detection signal _{(e 1, e 2, e} 3, e 4) (e 1 = e 2) and It deviates from the point of (e ₃ = e ₄ ) by time t.

This shift of the switching point causes a shift in the timing of exciting the armature coil 106 with respect to the magnetic poles on the rotor 102, resulting in an increase in torque ripple and uneven rotation, a decrease in starting torque, and an increase in exciting current. However, there is a problem that the performance of the brushless motor is deteriorated by causing a decrease in the torque constant.

The armature coil 106 (L1, L2, L3,
In order to avoid the influence of the magnetic field generated by the exciting current of L4) on the Hall element, the magnetic sensing surface of the Hall element is not a general Hall element molded product in which the magnetic sensing surface is parallel to the motor substrate 110, but a magnetic sensing element. The surface is the motor board 11
A special Hall element molded product in the plane direction perpendicular to 0 may be used.

If the magnetically sensitive surface is in the direction perpendicular to the motor substrate 110, the magnetically sensitive surface faces the permanent magnet 103, the output voltage of the Hall element increases, and the magnetic field generated by the excitation of the armature coil 106. However, a special Hall element molded product having a magnetically sensitive surface in a plane direction perpendicular to the motor substrate 110 is much more expensive than a general Hall element molded product. There is a problem that the price of the motor becomes expensive.

The present invention has been made to solve the above problems, and an object thereof is to use a general and inexpensive Hall element molded product, even if the Hall element is affected by a magnetic field. Exciting current is supplied to the armature coil at the correct timing to reduce torque ripple and rotation irregularity.
It is an object of the present invention to provide a drive device for a brushless motor, which improves deterioration of the performance of the brushless motor, such as a decrease in starting torque and a decrease in torque constant with an increase in armature coil excitation current.

[0019]

In order to solve the above-mentioned problems, a brushless motor drive device according to the present invention is a position signal generating means for generating a rotor position signal in response to a position detection signal provided by a rotor position detecting means. And a conduction control unit that outputs a conduction control signal based on the rotor position signal, generates an offset signal that cancels the phase shift based on the rotor position signal, and provides the position signal generation unit with the offset signal. It is characterized in that a timing correction means is provided.

Even if the rotor position detecting means is influenced by the magnetic field generated in the armature coil and generates a position detecting signal including a phase shift and provides it to the position signal generating means, the drive device is based on the rotor position signal. Since the timing correction means for generating the offset signal for canceling the phase shift and providing it to the position signal generation means is provided, the position signal generation means cancels and corrects the phase shift amount included in the position detection signal, and The rotor position signal can be generated at various timings, and the conduction control signal generated by the conduction control means based on this rotor position signal switches the power transistor of the drive output means at the correct timing to generate the armature coil exciting current. Can be generated.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a brushless motor drive device according to the present invention will be described below with reference to the accompanying drawings. 1 is a block diagram of a brushless motor drive device according to the present invention, and FIG. 2 is a timing diagram of the brushless motor drive device according to the present invention. Since the four-phase brushless motor described above is used for the configuration of the mechanical elements such as the rotor and the stator of the brushless motor and the arrangement of the hall elements, the description thereof will be omitted here with reference to FIG. To do.

1 and 2, the brushless motor driving device 1 detects the rotational position of the rotor 2 to generate position detection signals (e ₁ , e ₂ , e ₃ , e ₄ ) rotor position detecting means. 7 and the position detection signals (e ₁ , e ₂ , e ₃ ,
and a drive device 8 for generating a conduction control signal (i ₁ , i ₂ , i ₃ , i ₄ ) for controlling the excitation current of the armature coil 6 based on e ₄ ). i ₁ , i ₂ ,
Each of the armatures of the stator 4 having a four-phase configuration by connecting the armature coils 6 (L1, L2, L3, L4) in delta from the drive output means 9 for generating an exciting current based on i ₃ , i ₄ ). An exciting current is supplied to the coil 6 to apply a rotational driving force to the rotor 2 having the permanent magnet 3 fixed to the outer peripheral portion.

The rotor position detecting means 7 is provided with two Hall elements HG1 and HG2 for detecting the rotational position of the rotor 2. Each time the magnetic pole passes through the rotor position detecting means 7 by the rotational movement of the permanent magnet 3, the position is detected. Detection signals (e ₁ , e ₂ , e
₃ and e ₄ ) are generated and provided to the position signal generating means 81.

In the Hall elements HG1 and HG2, the phase difference between the position detection signals (e ₁ , e ₂ ) and (e ₃ , e ₄ ) which are the output signals thereof is {(π / 2 ) + Nπ} radians (n = 0, ± 1, ± 2, ...).

The position detection signals (e ₁ , e ₂ , e ₃ , e ₄ ) are
Each time the magnetic poles of the rotor 2 pass through the Hall elements HG1 and HG2, the position detection signals (e ₁ and e ₂ ) and (e ₃ and e ₄ ) have opposite phases to each other as shown in FIG. The phase difference between (e ₁ , e ₂ ) and (e ₃ , e ₄ ) is generated with a phase difference of π / 2.

The driving device 8 includes a position signal generating means 81 composed of two sets of differential amplifiers corresponding to the two Hall elements HG1 and HG2 provided in the rotor position detecting means 7, and a timing composed of two sets of offset amplifiers. Correction means 82 and 2
And a position detecting signal (e ₁ , provided by the rotor position detecting means 7).
Based on e ₂ , e ₃ , e ₄ ) the conduction control signals (i ₁ , i ₂ ,
i ₃ , i ₄ ) are generated and provided to the drive output means 9.

The position signal generating means 81 is a differential amplifier 81.
a and 81b, the position detection signals (e ₁ , e ₂ ) and (e ₃ , e ₄ ) provided by the rotor position detection means 7 and the offset signals (nf, n provided by the timing correction means 82).
Based on g), the rotor position signals (E ₁₂ , E ₂₁ ) and (E ₃₄ , E ₄₃ ) are generated and provided to the timing correction means 82 and the conduction control means 83.

The differential amplifiers 81a and 81b are provided with a differential amplifier circuit and differentially detect position detection signals (e ₁ , e ₂ ) and (e ₃ , e ₄ ) of opposite phases corresponding to the rotational position of the rotor 2. The position detection signals (ed ₁ , ed ₂ , e) which are amplified by the amplifier circuit and have distortion due to the influence of the magnetic field generated by the armature coil 6 are generated.
d _3, the ed _4), and corrected based on the offset signal supplied from the timing correction unit 82 (nf, ng), as shown in FIG. 2, the position detection signal _{(e 1, e 2),} (e 3 ,
e ₄ ) and the rotor position signals (E ₁₂ , E ₂₁ ) and (E ₃₄ , E ₄₃ ) which are in phase with each other and have a phase difference of (π / 2) in electrical angle according to the correct detection position of the rotor 2. .

FIG. 3 shows an example of the differential amplifier and the offset amplifier. In FIG. 3, the differential amplifier circuit included in the differential amplifier 81a has, for example, a position at which distortion occurs under the influence of the magnetic field generated by the armature coil 6 at the bases of the transistors Q11 and Q12 forming the differential amplifier circuit. Detection signals (ed ₁ , ed ₂ ) are connected, and each emitter has a resistor R
1 and R2 are connected to the respective current sources I ₁ connected to the constant voltage power source Vcc, and the connection points (points P3 and P4 in the figure) between the resistors and the current sources are transistors Q21 and Q2.
22 and the collectors are both grounded.

The emitters of the transistors Q21 and Q22 are connected to a common current source I ₂ connected to the constant voltage power supply Vcc, the collectors are grounded via the current sources common to the resistors R3 and R4, and the collectors are connected to the rotor. Position signal (E
₁₂ and E ₂₁ ) are supplied.

Further, the offset signal nf supplied from the offset amplifier 82b provided in the timing correction means 82 is connected to the base (point P3) of the one transistor Q21 forming the differential amplifier circuit, and the differential amplifier 81a is connected.
Control the input offset of the transistors Q21, Q2
Rotor position signal (E ₁₂ ,
E ₂₁ ) is corrected so that the timing corresponds to the correct detection position of the rotor 2.

The differential amplifier circuit provided in the differential amplifier 81b is also configured in the same manner, and the distorted position detection signal (e
d _3, the ed _4), and corrected based on the offset signal ng supplied from the timing correction unit 82, to generate a rotor position signal corresponding to the correct detected position of the rotor _{2 (E 34, E 43)} .

The timing correction means 82 includes offset amplifiers 82a and 82b, and the rotor position signals (E ₁₂ , E ₂₁ ) and (E ₃₄ , E ₃₄ ,
Based on E ₄₃ ), an offset signal (ng, nf) is generated to generate a differential amplifier (81b, 81) of the position signal generating means 81.
a).

The offset amplifiers 82a and 82b are provided with a constant current amplifier circuit, and based on the rotor position signals (E ₁₂ and E ₃₄ ), as shown in FIG. 2, a phase difference of (π / 2) in electrical angle is obtained. And each generate an offset signal (ng, nf) which is a rectangular wave with a duty ratio of 1: 1.

The phase of this offset signal (nf, ng) is, as shown in FIG. 2, the phase of the rotor position signal (E ₃₄ , E ₁₂ ) provided by the differential amplifiers 81b, 81a (position detection signal e ₃ , It is generated in a phase opposite to the disturbance magnetic field (f, g) based on the phase of e ₁ ).

As shown in FIG. 3, the offset signals (nf, ng) are applied to the base (P3 in the figure) of the transistor Q21 which constitutes the differential amplifier circuit of the differential amplifiers 81a and 81b.
The input offset of (± Kl ₀ * R1) is generated by flowing the current KI ₀ into or out of the point.

The offset amount of this input offset is set to a value that can cancel the error voltage generated in the Hall elements HG1 and HG2 by the disturbance magnetic field (f, g). The method of setting the offset amount uses the fact that the error voltage is proportional to the exciting current, and by measuring the proportional constant of (error voltage value / exciting current value) when the structure of the brushless motor is established, An offset amount that cancels the error voltage according to the exciting current can be set.

The exciting current value is detected, for example, from the potential of the exciting current detection terminal NF, and the current value of the variable current source KI ₀ is set based on this detected potential, or directly based on this detected potential. It is also possible to control the current value of the variable current source KI ₀ .

The constant current amplifier is, for example, as shown in FIG. 3, two transistors Q ₃₁ , whose bases are connected to each other,
A current mirror circuit is constituted by Q ₃₂ , and the collector is connected to the constant voltage power supply Vcc through the variable constant current source KI ₀ set to the current value KI ₀ , and each emitter is grounded. In addition, the emitter area of the transistors Q ₃₁ and Q ₃₂ is A
₃₁ and A ₃₂ , the emitter area ratio is (A ₃₁ : A ₃₂ =
2: 1).

The transistor Q _32, as well as to connect the collector base and, transistor Q ₃₃ the emitter grounded
Are connected in parallel. The rotor position signals (E ₁₂ , E ₃₄ ) are
It is connected to the base of the transistor Q ₃₃ via a resistor, and the offset signal (nf, ng) is supplied from the collector of the transistor Q ₃₁ .

The conduction control means 83 is a differential distributor 83a, 8
3b, based on the rotor position signals (E ₁₂ , E ₂₁ ) and (E ₃₄ , E ₄₃ ) supplied from the position signal generating means 81,
The conduction control signals (i ₁ , i ₂ , i ₃ , i ₄ ) are generated and provided to the drive output means 9.

The differential distributors 83a and 83b are equipped with a differential amplifier circuit to saturately amplify the rotor position signals (E ₁₂ , E ₃₄ ), and as shown in FIG. Conduction control signals (i ₁ , i ₂ ), which are rectangular waves of phase,
(I ₃ , i ₄ ) is generated.

As shown in FIG. 2, the conduction control signals (i ₁ , i ₂ ) and (i ₃ , i ₄ ) are the position detection signals (e
₁ , e ₂ ) and (e ₃ , e ₄ ) are (e ₁ = e ₂ ) and (e
₃ = e ₄ ), and they have a phase difference of π / 2 with each other. For example, the signal pair of the conduction control signals (i ₁ , i ₃ ) drives the power transistors (Q 1, Q 3) of the drive output means 9 during the phase (π to 3π / 2), and the conduction control signal (i ₂₎ , I ₄ ) of the signal pair of the power transistors (Q2, Q4) of the drive output means 9 during the phase (0 to π / 2).
Drive.

The drive output means 9 comprises power transistors (Q1, Q2) having a pair of source side and sink side,
A power amplifier with (Q3, Q4) is provided, and terminals (T1, T2), (T3,
T4) is connected to the connection point of the four armature coils 6 connected in delta.

The pair of power transistors on the source side and the sink side are respectively driven by the signals of the conduction control signals (i ₁ , i ₂ ) and (i ₃ , i ₄ ) supplied from the conduction control means 83, and the armature is obtained. An exciting current is supplied to the coil 6.

Source side power transistors (Q1, Q
The collectors of 2) are both connected to the constant voltage power supply Vcc via the resistor Rnf, and the sink side power transistor (Q
3, Q4) emitters are both connected to ground.

For example, a pair of power transistors (Q1, Q3) during driving has emitters and collectors connected via terminals (T1, T3) to connection points of armature coils (L1, L4) and (L1, L2). Continuity control signals (i ₁ , i ₃ ) provided by the continuity control means 83 are supplied to the base.

Similarly, the paired power transistors (Q2, Q4) at the time of driving are connected to the armature coils (L2, L3) and (L3, L4) through the terminals (T2, T4) at the emitter and collector. Connected to the point, the base is supplied with the continuity control signals (i ₂ , i ₄ ) provided by the continuity control means 83.

The conduction control signals _{(i 1, i 3, i} 2, i 4) in the power transistor (Q1, Q2, Q3, Q4 ) the order to drive the position detection signal _{(e 1, e 2, e} 3, The description will be made based on the timing of e ₄ ).

The position detection signals (e ₁ , e ₂ ) are (e ₁ >
power transistors Q1 in the period _{e 2), (e 1 <} e 2)
Power transistors Q2 in the period, the position detection signal _{(e 3, e 4),} (e 3 <e 4) power transistor Q3 in the period, (e3> power transistor Q in the period e4)
4 are turned on, and the power transistors are turned off in other periods.

Source side power transistors Q1 and Q2
The on / off switching point of is the position detection signal (e ₁ ,
e ₂ ) (e ₁ = e ₂ ), and the on / off switching points of the power transistors Q 3 and Q 4 on the sink side are (e ₃ = e ₄ ) of the position detection signals (e ₃ , e ₄ ). ) Match the timing.

The resistor Rnf is a resistor for detecting the exciting current, and the voltage at the exciting current detecting terminal NF is fed back to the exciting current setting means (not shown) provided with a control circuit to obtain the conduction control signal (i. ₁ , i ₂ , i ₃ , i ₄ ) to generate a control signal for stabilizing the differential distributor (83a, 83a).
b) and adjust the conduction control signals (i ₁ , i ₂ , i ₃ , i ₄ ) to stabilize the excitation current supplied by the drive output means 9.

As described above, in the brushless motor drive device according to the present invention, the rotor position detecting means is influenced by the magnetic field generated in the armature coil and generates the position detecting signal including the phase shift to generate the position signal generating means. The position signal generating means for generating the rotor position signal in response to the position detection signal provided by the rotor position detecting means, and the conduction control means for outputting the conduction control signal based on the rotor position signal. The drive device is provided with the timing correction means for generating the offset signal for canceling the phase shift based on the rotor position signal and providing it to the position signal generation means. The shift position can be canceled and corrected to generate a rotor position signal with accurate timing, and conduction can be performed based on this rotor position signal. Conduction control signals generated by the control unit can generate an armature coil excitation current by switching the power transistors of the driving output device at the right time.

Next, the drive unit 8 configured as described above.
The offset amplifiers (82a, 82b) included in the timing correction means 82 and the differential amplifiers (81a, 81b) included in the position signal generation means 81 have distortion due to the influence of the magnetic field of the armature coil 6. Position detection signal (ed ₁ ,
ed _2, ed _3, the ed _4), the offset signal timing correction means 82 is provided (nf, to cancel the distortion by ng), the correct position detection timing of the rotor position signal of the rotor _{2 (E 12, E 21)} , The correction operation for generating (E ₃₄ , E ₄₃ ) will be described with reference to FIGS. 1, 2 and 4.

In the period of (0 to π / 2), the position detection signals (e ₁ , e ₂ ) provided by the hall element HG1 are (e ₁
Since <e ₂ ) the power transistor Q2 is turned on and the position detection signals (e ₃ , e ₄ ) provided by the hall element HG2 are (e _3
3> e ₄₎ since the power transistor Q4 is turned on, the path of the exciting current of the armature coil 6, L3 of the armature coils 6
In the direction of terminals (T2 → T4), armature coil 6 (L2
→ L1 → L4) is in the direction of the terminals (T2 → T3 → T1 → T4), and the exciting current value of each path has a ratio of 3: 1.

[0056] The coil C ₃₁ in the vicinity of the Hall element HG1 by the excitation current to the N pole, but the coil C ₂₁ becomes S pole, 3 of the excitation current of the coil C ₃₁ is the excitation current of the coil C ₂₁
Since it is double, the magnetic field that affects the Hall element HG1 by energizing the armature coil 6 is the N pole. Similarly, Hall element H
The coil C _{32 in} the vicinity of G2 has an N pole and the coil C ₄₂ has an S pole. However, since the exciting current of the coil C ₃₂ is three times the exciting current of the coil C ₄₂ , the Hall element HG2 is energized by the armature coil 6. The magnetic field that affects at is the N pole.

The magnetic field of the N-pole increases the position detection signals (e ₁ , e ₂ ) provided by the Hall element HG1 and decreases the position detection signals (e ₃ , e ₄ ) provided by the Hall element HG2. Is.

Next, during the period {(π / 2) to π}, the position detection signal (e ₁ ,
Since e ₂ ) is (e ₁ > e ₂ ), the power transistor Q1 is turned on, the power transistor Q2 is turned off, and the hall element H
Position detection signal G2 is provided (e _3, e ₄₎ is (e _3>
e ₄ ), which is the same as in the period (0 to π / 2) with the power transistor Q4 kept on. The path of the exciting current of the armature coil 6 is L4 of the armature coil 6.
In the direction of terminals (T1 → T4), armature coil 6 (L1
→ L2 → L3) is in the direction of the terminals (T1 → T3 → T2 → T4), and the exciting current value of each path has a ratio of 3: 1.

By this exciting current, the coil C ₃₁ near the Hall element HG1 becomes the N pole, and the coil C ₂₁ also becomes the N pole, and the magnetic field affecting the Hall element HG1 by the energization of the armature coil 6 becomes the N pole. The coil C ₃₂ N pole in the vicinity of the Hall element HG2, although the coil C ₄₂ becomes S pole, 3 of the excitation current of the coil C ₄₂ is the excitation current of the coil C ₃₂
Since it is double, the magnetic field that affects the Hall element HG2 by energizing the armature coil 6 is the S pole.

Similarly, during the period {π to (3/2) π}, the power transistors Q1 and Q3 are turned on, and the magnetic fields that influence the Hall elements HG1 and HG2 by energizing the armature coil 6 are both S. Become a pole.

During the period {(3/2) π to 2π}, the power transistors Q2 and Q3 are turned on, and the magnetic field affecting the Hall element HG1 by energizing the armature coil 6 is the S pole and the Hall element HG2. The magnetic field affected by the energization of the armature coil 6 is the N pole.

During the entire period up to the above (0 to 2π), the Hall elements (HG1, HG1 and HG) are activated by energizing the armature coil 6.
The disturbance magnetic field (f, g) received by 2) is generated at the timing of (f, g) as shown in FIG.

The change point of the disturbance magnetic field f from the N pole to the S pole is
Position detection signals (e ₃ , e ₄ ) provided by the Hall element HG2
Coincides with the timing of (e ₃ = e ₄ ), and the strength of the disturbance magnetic field is proportional to the value of the exciting current that is applied to the armature coil 6. Therefore, the Hall element HG1 affected by the disturbance magnetic field f Voltage value of the position detection signal (e ₁ , e ₂ ) generated by the excitation current detection terminal NF
Of the disturbance magnetic field f based on the phase of the position detection signal e ₃ generated by the Hall element HG2 by the offset amplifier 82b provided in the timing correction means 82.
A differential amplifier circuit (provided that the amplification degree is A) provided in the differential amplifier 81a for generating the offset signal nf having a phase opposite to that of and for processing the position detection signals (e ₁ , e ₂ ) provided by the Hall element HG1. The rotor position signal E ₁₂ is processed and generated in the following manner by being applied to the offset adjustment terminal (point P3).

In FIG. 3, the potentials at points P3 and P4 are V ₃ and V ₄ , respectively, and the transistors Q11 and Q12.
The base-emitter voltages V _BE1 and V _BE2 are equal to each other and are set to V _BE (V _BE = V _BE1 = V _BE2 ). When the error voltage between e _{1 and} e ₂ due to the disturbance magnetic field f is ef and the offset voltage due to the offset signal nf is V _nf (V _nf = KI ₀ * R1),

[0065]

[Number 1] _{V 3 = e 1 + (e} f / 2) + V BE + (I 1 + V nf) * R1 V 4 = e 2 - (e f / 2) + V BE + I 1 * R1

[0066]

[Number 2] _{E 12 = A (V 3 -V} 4) = A (e 1 -e 2 + e f + V nf) ≒ A (e 1 -e 2)

As shown in Equation 2, the position detection signal (e ₁ ,
The phase shift due to the disturbance magnetic field f included in e ₂ ) is canceled, and the rotor position signal E ₁₂ is corrected to a signal having a timing corresponding to the correct detected position of the rotor 2.

Similarly, a voltage of substantially the same level as the voltage level of the position detection signals (e ₃ , e ₄ ) generated by the Hall element HG2 affected by the disturbance magnetic field g is applied to the excitation current detection terminal N.
An offset amplifier 82a, which is determined based on the potential of F, is provided in the timing correction means 82, and an offset signal ng having a phase opposite to the disturbance magnetic field g with reference to the phase of the position detection signal e ₁ generated by the Hall element HG1. A differential amplifier circuit provided in the differential amplifier 81b for generating and processing the position detection signals (e ₃ , e ₄ ) provided by the Hall element HG2 (the amplification degree is A
By adding to the offset adjustment terminal (point P3), the rotor position signal E ₃₄ is corrected to a signal at a timing corresponding to the correct detected position of the rotor 2.

[0069]

As described above, in the brushless motor drive device according to the present invention, the rotor position detecting means receives the influence of the magnetic field generated in the armature coil to generate the position detecting signal including the phase shift. Position signal generating means for generating a rotor position signal in response to the position detection signal provided by the rotor position detecting means, even if provided to the position signal generating means, and conduction control for outputting a conduction control signal based on the rotor position signal. And a timing correction means for generating an offset signal for canceling the phase shift based on the rotor position signal and providing the offset signal to the position signal generation means, the position signal generation means being included in the position detection signal. The phase shift amount can be canceled and corrected, and the rotor position signal with accurate timing can be generated, and based on this rotor position signal Since the conduction control signal generated by the communication control means can switch the power transistor of the drive output means at the correct timing to generate the armature coil exciting current, a general and inexpensive Hall element molded product can be obtained. Even if the Hall element is affected by the magnetic field by using, the exciting current is supplied to the armature coil at the correct timing, torque ripple and rotation unevenness are small, and the torque due to the starting torque decrease and the armature coil exciting current increase It is possible to provide a drive device for a brushless motor, which improves deterioration of the performance of the brushless motor such as a decrease in constant.

[Brief description of the drawings]

FIG. 1 is a block configuration diagram of a brushless motor drive device according to the present invention.

FIG. 2 is a timing diagram of a brushless motor drive device according to the present invention.

FIG. 3 is an example of a differential amplifier and an offset amplifier.

FIG. 4 is a structural diagram of a 4-phase brushless motor.

FIG. 5 is a schematic configuration diagram of a conventional brushless motor drive device.

FIG. 6 is a timing diagram of a conventional brushless motor drive device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Brushless motor drive device, 2 ... Rotor, 3 ... Permanent magnet, 4 ... Stator, 6 ... Armature coil, 7 ... Rotor position detection means, 8 ... Drive device, 9 ... Drive output means, 81
... Position signal generating means, 81a, 81b ... Differential amplifier, 8
2 ... Timing correction means, 82a, 82b ... Offset amplifier, 83 ... Continuity control means, 83a, 83b ... Differential distributor, C ₂₁ , C ₃₁ , C ₃₂ , C ₄₂ ... Coil, E ₁₂ , E ₃₄ ,
E _21, E ₄₃ ... rotor position signal, HG1, HG2 ... Hall elements, I _1, I ₂ ... current source, KI ₀ ... variable current source, L1,
L2, L3, L4 ... Armature coil, NF ... Excitation current detection terminal, P3 ... Offset adjustment terminal, Q1, Q2, Q3,
Q4 ... Power transistor, Q11, Q12, Q21,
Q22 ... Transistor, Rnf ... Resistor, T1, T2, T
3, T4 ... terminal, Vcc ... constant-voltage power supply, e _1, e _2,
e ₃ , e ₄ ... Position detection signal, ed ₁ , ed ₂ , ed ₃ , ed ₄
... position detection signal subjected to _{distortion, i 1, i 2, i} 3, i 4 ... conduction control _{signal, id 1, id 2, id} 3, id 4 ... conduction control signal having a time delay, f, g ... disturbance Magnetic field, ng, nf ... Offset signal.

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Hideki Maedo 2-5-5 Keihan Hondori, Moriguchi City, Osaka Sanyo Electric Co., Ltd. (72) Inventor Masao Mizumoto Keihan Hondori, Moriguchi City, Osaka Prefecture 2-5-5 Sanyo Electric Co., Ltd.

Claims (1)

[Claims] 1. A rotor position detecting means for detecting a rotational position of a rotor provided with a permanent magnet having a multi-pole driving magnetic pole to generate a position detection signal, and an exciting current is controlled based on the position detection signal. A drive device for generating a conduction control signal;
The rotor, the stator having the two or more-phase armature coils for generating the magnetic field by flowing the exciting current, and the drive output means for supplying the exciting current, and depending on the magnetic field generated by the armature coil. In a brushless motor drive device for driving a brushless motor configured to generate a rotational driving force in the rotor, position signal generating means for generating a rotor position signal according to a position detection signal provided by the rotor position detecting means; Timing for generating an offset signal for canceling a phase shift based on the rotor position signal and providing the offset signal to the position signal generating means in the drive device, which includes a conduction control means for outputting a conduction control signal based on the rotor position signal. A drive device for a brushless motor, comprising a correction means.