JPS60134792A - Driving device of motor - Google Patents

Abstract

PURPOSE:To control conduction of 3-phase coils in a simple circuit without using a phase shifter by obtaining 3-phase signals upon rotating of a rotor by using at least two magnetosensitive elements and processing them in a control signal composite circuit. CONSTITUTION:3-phase signals having a phase difference of 120 deg. obtained from a magnetosensitive element are inputted to input terminals 21-23. After these signals are amplified by head amplifiers 24-26, they are subtracted by subtractors 27-29, and inputted to zero cross comparators 30-32. The outputs of the amplifiers 24-26 are inputted to zero cross comparators 33-35. The outputs of the comparators 30-35 are inputted to EX-OR36-41, and transistors 42-48 are controlled by the outputs. The currents of coils 49-51 of phases U, V and W are controlled by the transistors 42-48.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a motor drive device suitable for use in a brushless motor having an 8-pole magnetized rotor.

BACKGROUND TECHNOLOGY AND PROBLEMS Conventionally, in a brushless motor that has a rotor consisting of four-pole magnetized magnets and six-phase coils, the rotational position of the rotor is detected and current is sequentially passed through the three-phase coils for a predetermined period of time. That's what I do. As the position detector for the rotor, as shown in FIGS. 1 and 2, a position detection magnet aυ with two poles magnetized on a plane is placed on the rotation axis α2 of the rotor. A detector (14) is used which detects the rotation of the magnet αυ using a magnetically sensitive element (101').This detector α produces a detection signal α shown in FIG. 11(a) and the following equation. β and γ are obtained, and a switching signal for the coil is created based on these signals.

α=K sin 2θ β=Ksin (2θ−120°) γ=Ksin (2θ−2406) where K: constant, θ: direction of the magnetic field acting on the magnetically sensitive element (2)′.

However, since a two-pole magnetized magnet (11) is used, each of the α, β, and γ signals changes only two cycles per rotation of the rotor. This blister detector (ta, f) cannot be used with a brushless motor ζ that has a rotor consisting of 8-pole magnetized magnets.In a motor that has a rotor with 8-pole magnetization,
In order to energize the 3-phase coil in both directions at 120°,
It is necessary to apply current to each of the U-phase, ■-phase, and W-phase coils at the timing shown in FIG. 12. In order to create a switching signal having the above timing based on the above signals α, β, and γ, each signal α, β, and γ is phase-shifted by a predetermined amount by a phase shift circuit, and based on these phase-shifted signals, It is necessary to create a switching signal. In that case, whether the phase shift circuit is an analog configuration or a digital configuration, the circuit configuration becomes extremely complicated and there are also problems in accuracy.

Purpose of the Invention The present invention provides a brushless motor having an 8-pole magnetized rotor, in which a 6-phase coil is connected to 12
The present invention provides a drive circuit that conducts current in both directions at 0°.

Summary of the Invention The present invention provides a predetermined signal to a six-phase coil of a brushless motor having an eight-pole magnetized rotor by supplying the signals α, β, and γ to a circuit using a subtraction circuit, an exclusive OR circuit, etc. Control signals for bidirectional energization of 120° are synthesized at the same timing.

Examples First, prior to examples of the present invention, we will explain the following examples that can be applied to the present invention.
An embodiment of a magnetically sensitive element that senses the direction of a magnetic field will be described. This magnetically sensitive element was proposed by the present applicant in Japanese Patent Application No. 79655/1984, etc., and an outline of the magnetically sensitive element will be explained here.

Figure 6 does not show the structure of the magnetically sensitive element α0), in which a ferromagnetic element (A) having an anisotropic effect of magnetoresistance, such as nickel cobalt, is placed on the surface of a substrate (1) made of glass or the like.
A thin film (B) is formed. This element (4) (2) can be formed by depositing a ferromagnetic material in a comb-teeth shape or by depositing it on the entire surface and then etching it. Element (4)
(B) shows multiple straight sections (2 people) (2
B), bent portions (3A), (6B), and friends that connect these, and the straight portions (, 2A) (
2B) are arranged substantially perpendicular to each other. Further, the respective ends (4AX4B) of the straight line portions (2A) (2B) are connected, and the elements (A)@ are connected in series.

An output terminal (5) is formed at the connecting portion, and current terminals (7A) (7B) are formed at the other ends (6A) (6B) of the straight portions (2A) (2B), respectively. These terminals (5) (7A) (7B) are formed of a conductive thin film.

Figure 4 is a diagram of the operating principle, in which the current terminals (7A) (7B) are connected to the power supply (8), and one current terminal (7B) is grounded, making up the magnetoelectric conversion circuit (9) as a whole. are doing.

Now, apply a magnetic field H of sufficient strength to saturate magnetize the elements (G) and (B) in the plane formed by the elements (4) and 2 in the direction of the straight line part of the element (2 people), that is, in the current direction. , each electric resistance 4 of the element (A)
ρB changes, and the change is expressed by the following equation using the angle θ.

ρA−ρ↓5in2θ+ρ, CO32θ ・・・・・・
・・・・・・■ρB−ρupper cO52θ+ρip 5in2
θ ・・・・Mountain・ ■However, ρ work is element (A) @
Element (A) (B) when saturated magnetized perpendicular to the current
The electric resistance, ρ, of ) is the electric resistance of the element (g) (6) when it is saturated magnetized in the direction parallel to the current.

Also, the voltage (2) at the output terminal (5) is the power supply voltage V because the elements (A) and (B) are connected in series. Then, it is expressed by the following formula.

By substituting the 00 formula into the ρFl 0 formula and rearranging it, we get (However, Δρ−ρ, −ρ□). In this substitution (2), the first term on the right side represents the reference voltage, and the second term represents the amount of change ΔVθ, which is expressed as Δρ. However, 2ρ0 - ρ1 + ρ, where ρ0 is the electrical resistance in the demagnetized state.

Therefore, the voltage Vθ at the output terminal (5) changes depending on the direction of the magnetic field H, and as shown in Figure 5, the output change is minimum when the magnetic field direction is 0° and 180°, and when the magnetic field direction is 90° and 270°. It becomes a sine waveform that reaches its maximum value.

FIG. 6 shows an equivalent circuit, which can be considered by assuming that the element (6) is a variable resistor whose resistance value changes depending on the direction of the magnetic field H.

When such a magnetically sensitive element 00) is used as the magnetically sensitive element (ID)' of the detector (+4) in Figs. 1 and 2, if the rotor rotates in the direction of the arrow, the magnetically sensitive element (10)
By changing the direction of the magnetic field of 1υ against the magnet, the output voltage Vθ shown in FIG.
is obtained. The element of the magnetically sensitive element (10) (g)■)
If the pattern of is shifted by φ° in mechanical angle, the output voltage ■θ
A phase difference of 2φ° occurs in electrical angle.

FIG. 7 shows an embodiment of the detection circuit, in which the element (A)
) are used to form a bridge configuration, and the output voltage e1. e2 is the differential amplifier ([Finally, the output voltage e according to the rotation from this differential amplifier (15)
I'm trying to get a. By forming the mushroom in this way, the temperature of the circuit can be compensated.

FIG. 8 shows a magnetically sensitive element (101) in which two sets of elements (A) and (B) are formed. The two sets of elements (G) and (B) are formed on the same substrate, and the output voltage e, A terminal for taking out +02, a 10B power supply terminal A, and a ground terminal (GND) are provided.

A magnetically sensitive element Qfi) is used on the detector side in Figs. 1 and 2, and in order to obtain the signals α, β, and γ, An element having a pattern tilted by φ-60° at the angle, that is, having a phase difference of 120° at the electrical angle (a magnetically sensitive element in which 0(2) is formed)
It is used in conjunction with the magnetically sensitive element (10) of FIG. Actually, a magnetically sensitive purple-f (102) is used in which the magnetically sensitive element on which the above element (Q(2) is formed) has a bridge structure similar to that shown in FIG. It can be obtained by stacking four magnetically sensitive elements (101) shifted by 60 degrees from each other.Alternatively, four elements (6) and four elements (Q(D) and They may be formed by alternately arranging them.

FIG. 9 shows an equivalent circuit of a magnetically sensitive element (10g) consisting of the magnetically sensitive elements (10+) and (102), in which the output voltage e1. When e2 is obtained, the output voltage e3 * from the magnetically sensitive element (102) is
I'm trying to get e4. Furthermore, the signal of αdKsin2θ can be obtained based on the above e1 and e2,
Based on the above “5 t e4, the above β= Ksio (2
A signal of θ-120°) can be obtained. Also α, β
The above γ-Ksin (2θ-240
°) signals can be obtained. #, Motoko (4) (b)
The signal γ may be obtained using a magnetically sensitive element having a pattern shifted by φ-120° from the pattern of .

Next, α obtained from the magnetically sensitive element (105).

An embodiment of the present invention in which a six-phase coil is energized at the timing shown in FIG. 12 based on the β and γ signals will be explained in detail. FIG. 10 shows the circuit configuration, and FIG. 11 shows the output waveforms of each circuit.

In FIG. 10, signals α, β, and γ shown in FIG. 11(a) obtained from the magnetically sensitive element (1os) are supplied to the input terminal H (22 (c). These signals α.

After β and γ are amplified by the head amplifier (24) (251 (2tp), the signal α is added to the subtraction circuit (27) (2 (to)) and the zero cross comparator 0. The signal β is added to the subtraction circuit (to) (c) and zero cross comparator (34
). The signal γ is added to the subtraction circuit (2Hη) and the zero cross comparator (c).
> α-γ, β-α, γ-β in 12E629, respectively
subtraction is performed, and the subtraction outputs a and b shown in FIG. 11(e) are
, e is obtained. These subtraction outputs a, b, and c are respectively added to zero cross comparators C3f) (31) (3e. As a result, the above comparators (to) 0υ(3
3, signals a', b', and c' shown in FIG. 11(d) are obtained. In addition, the comparators (c), (c), (c), the signals α', β', and r' shown in FIG. 11(b) are obtained. These signals α', β', and γ' can be used as switching signals when a motor having a four-pole magnetized rotor is energized in both directions through 180°. The above signal a' is added to an exclusive OR circuit (hereinafter referred to as EX-OR) (to) (37), and the above signal b' is applied to EX-0RG?
)(to), and the above signal C' is added to EX-0RC((
(to) (added to 3 smells).

Also, the above signal α' is added to EX-ORI31 (4Q, upper □! As a result, from EX-OR(3G) to (41), the output signals C'■a/ and a/ shown in FIG. 11(e) are obtained.
■b/ , b/■C′〜, γ′■α′, α′■β′,
γ' of β' are obtained respectively.

On the other hand, a transistor (42
(43 series circuits, transistors (4 (1) (4 mice) series circuits, and transistors (47) (48) series circuits are connected in parallel.U at the connection point of each series circuit.
Phase, V phase and W phase coils (<:>) 60) 61)
One end of each coil (49) (50) is connected respectively.
l! 51) The other ends are commonly connected. And the above EX-oR (3
The operations of these transistors (421 to (48)) are controlled by applying the above output signals of n to (4υ) as shown.

According to the above, it is possible to synthesize control signals for energizing each coil at the timing shown in FIG. 12 using a simple circuit configuration based on the signals α, β, and γ without using a phase shift circuit. This embodiment uses an 8-pole magnetized rotor, but the present invention uses a rotor with 12 poles, 16 poles, etc.
It is possible to apply to a motor having a rotor magnetized to a multiple of 4, such as .

Effects of the invention Position detection can be performed. In that case, a six-phase signal α with a phase difference of 120° is obtained from the detector in accordance with the rotation of the two-pole magnetized position detection magnet 0υ.

A control signal for energizing the six-phase coil can be synthesized based on β and γ. The circuit for synthesizing this control signal can be implemented with a simple circuit configuration without using a phase shift circuit or the like, and without requiring any particular precision.

[Brief explanation of the drawing]

Fig. 1 is a theoretical side view of a rotor rotational position detector, Fig. 2 is a first plan view, Fig. 3 is a plan view showing an example of a magnetically sensitive element, and Fig. 4 is a principle circuit diagram. , #E Figure 5 is an output voltage waveform diagram, Figure 6 is a circuit diagram, Figure 7 is a block diagram of the detection circuit, Figure 8 is a plan view of the magnetically sensitive element made with Prefuji 1f#, Figure 9 10 is an equivalent circuit diagram showing another embodiment of the magnetically sensitive capacitor; FIG. 10 is a circuit diagram showing another embodiment of the invention;
Figure 11 shows the timing chart 1 and 1 of the 101st
Figure 2 shows a control system for providing 120° bidirectional communication to the 6-phase coil of a motor that drives an 8-pole magnetized rotor. In addition, in the symbols used in the drawings, (10j×10°) (105) ...... Magnetically sensitive element (lυ- ......... for position detection Magnet az・・・・・・・・・・・・・・・Rotation axis ■・・・・・・
...Rotary position detector (27) (twice often...
・・・・・・Subtraction circuit C+s3+7)flc+e(4[l
l(4→...exclusive OR circuit fPIi5[)451
)・・・・・・・・・・・・It is a coil. Agent Ueya Yoshio Tokitsuneka Toshiki Sugiura

Claims (1)

[Claims] By detecting the magnetic field accompanying the rotation of the rotor using at least two magnetically sensitive elements, the
By obtaining a phase signal and supplying this three-phase signal to a control signal synthesis circuit consisting of a subtraction circuit and an exclusive OR circuit, 4n (n=2.3......) poles are obtained. A motor drive device configured to obtain a control signal for energizing a three-phase coil of a motor having a magnetized rotor in 120 degrees in both directions.