JPS5851790A - Dc brushless motor - Google Patents

Abstract

PURPOSE:To obtain a DC brushless motor having no torque ripple by connecting in parallel or diagonally four stator coils between four drive switching elements which are energized by the outputs of a position detectors connected in a bridge. CONSTITUTION:The position detection outputs from Hall elements H1, H2 are applied to the base inputs of transistors Tr1-Tr4 through transistors Tr5- Tr9, thereby controlling the energizing currents of stator coils L1-L4 connected between transistors Tr1-Tr4 as shown. In other words, the current level switching points of coil currents I1-I4 controlled in energization via the Hall voltage e1-e4 coincide with zero cross point of Hall voltages e1-e4. Accordingly, even if the amplitude of the Hall voltage increased due to the output unbalance of the Hall elements H1, H2, the current flowing angle of the coil current does not vary. A speed error signal is inputted to the transistor Tr10, thereby controlling the conductivity of the transistors Tr2, Tr4.

Description

DETAILED DESCRIPTION OF THE INVENTION The DC brushless motor of the present invention is capable of smoothly driving a rotor regardless of variations in the performance of a rotor position detector;
Furthermore, the purpose of the present invention is to provide a DC brushless motor that can increase the combined torque.The first opening is enlarged.A circuit diagram of an example of a drive circuit of a conventional DC brushless motor is shown. In the figure, Hall element iris 1. When a current is passed through the current terminal of H3, as the rotor rotates, the Hall output voltage 1.・3.・2.・4 is taken out and the transition is vertical 11. ~”r14 haho/L’ output voltage・・～・
The negative voltage of 4 is conducted for a part of the period 7 (that is, the period of the lowest level compared to 4, which will be described later). Due to the conduction of transistors 'rtt~TE1 and 4, transistor 'rl
l~Troll is conducted, and as the rotor rotates, the stator coils L, ~L4Kj as shown in the lower part of the figure, coil currents, ~x4 (in the same figure, B and ~B4 are the respective coils L, ~
(indicates the magnetic flux induced in L4) flows sequentially in a time-division manner to rotate the rotor in one direction.

At this time, the amplitude of the coil current I, ~x4 is controlled by a speed error signal corresponding to the rotational speed of the rotor entering the terminal 1, and the speed is controlled.

On the other hand, the torques T, ~T generated in the coils L, ~L4
4 is as shown in FIG. 2 0-(1), and the resultant torque is as shown in FIG. □By the way, since the current flow section of the coil current in this conventional motor, ~x4, corresponds to the lowest level period of the Hall output voltage . For example, if the amplitude of the Hall output voltage becomes large as shown by the broken line in FIG. This also occurs due to an imbalance in the DC potentials of the voltage terminals of the Hall elements H1, H, an imbalance in the Hall output waveform, and the like. This causes an increase in torque ripple and rotational unevenness, etc.
There was a drawback that the electric motor could not be driven reliably.

Therefore, in order to eliminate this drawback, there is a conventional logic processing type %O in which the Hall output voltage is waveform-shaped into a rectangular wave and a coil current is caused to flow by the waveform-shaped voltage.
This product tends to generate rounding noise with a sharp waveform,
In addition, the Hall element O product sensitivity of conventional 2') was made the same], 2
Although there is a device that includes a circuit that aligns the DO levels of the voltage terminals of the two Hall elements, the circuit is complicated and cannot be constructed at a low cost.

The above-mentioned drawbacks have been eliminated, and one embodiment thereof will be described with reference to FIG. 3 and subsequent figures.

FIG. 3 shows a circuit diagram of an embodiment of a DC brushless motor according to the present invention. In the same figure, stator coil L and "I"
With CxIi! J4) has a phase difference of approximately (7+n x ) radians (""s±1.±2...) in electrical angle, and coils 1. and -1 ("2 and L4) are electrical angles approximately (π+!
l g ) has a phase difference of radians ("-a, ±1.±2, -). The - ends of the coil L and the coil L are connected to the collector of the transistor "rl, and the coils L, I and the coil One end of It4 is connected to the collector of transistor T□, the other end of coil L and coil L4 is connected to the collector of transistor Tr, and the other ends of coils L, R and coil L are connected to the collector of transistor T4. The base of the transistor ``r10'' is connected to the voltage terminal of the Hall element E through the transistor ``re Yt, and the base of the transistor T is connected to the voltage terminal of the Hall element E through the transistor Tr, t-.
The base of the transistor τr20 is connected to the voltage terminal ■ of the Hall element H2 via the transistor "rs,"
The bases of the transistors Tr4 are respectively connected to the Hall element IIp voltage terminal (2) via the transistor 'r4.

The emitters of transistors T and T are the positive power supply V.

The transistor Tr? # The emitter of "re" is connected to the negative power supply V through the resistor R6, and the transistor T r2 #
to the negative power supply V, through the emitter resistor R9 of T1”4,
The emitters of the transistors Tr, , r5 are resistors Rp
Transistor 17 is connected to the positive power supply V through resistor R4, and speed error signal input terminal 1 is connected to resistor R,)
Lunge state 1. . , the transistor through the resistors R, l
1"2' is connected to the emitter of the transistor Tr, and also connected to the base of the transistor Tr through a resistor R8, and to the positive power supply V through the resistor R,l. The output signals of elements H1 and Tl are electrical angles (
-10nπ) radians (n-0, ±1.±2°...).

In the figure, when a current is supplied to the current terminal of the Hall element H1"2 and the rotor is rotated, the Hall elements H1, H
From the voltage terminals ■, ■, ■, ■, the Hall voltage as shown by the dotted lines in Figure 4) to (b) @1. @s a e
2 *・4 is extracted. As shown in FIG. 4 (A) to ψ), the positive voltage period (electrical angle π) of the Hall voltage . (Electrical angle π) Transistor Tr2 and transistor T4 are respectively turned on during the negative voltage period of Hall voltage e2, and are respectively turned off during the other periods. For example, in the periods ... -, transistor Tr1
r, is on, and transistors Tr1 #Tr4 are off. Accordingly, the current from the power source V is the transistor T coil L, the transistor Tear 7, and the resistor rs'.
4% resistor R, t- flows to the power supply V, while transistor T□, coil L coil L coil-4, transistor P
2' Star "T2% Flows into the power supply V2 through the resistor R,l. Therefore, the current x4 flowing through the coil L4, as shown in No. 4g111!4, changes its level to the current I1.
, the current I1. flowing through the coils IJ, , Ls is larger than that of the current I1. As shown in xt (in the same figure) and IG), the level is i of current x4 (coil L,, !J,,
The sum of the net resistances of coils II and IJ2 is three times that of coil II4), and the current flowing through coil IJ2 is 'xμ. The current is I4. In other periods as well, the same operation is performed to expand rI! to each coil L, ~L4! to J)～
Step-like current as shown in (b)! .

~x4 flows.

When looking at the coil current during the electrical angle period, a transistor is a must! 1. When either transistor T is on, either transistor T2 or rs transistor T4 is turned on, and a large current flows only in the coil of one phase, and the coils of the other three phases have their respective − current will flow. Finally, other three-phase coils are connected in parallel to the Fi line to both terminals of the coil through which the large current flows.

In addition, in the same figure) to (b), B and ~B4 are coils 111.
~ Shows the magnetic flux induced in L4 〇 In this way, the output voltage of Hall elements H, , H2 ・1 ~ ・
The transistors ``r1~d'' and the coil L-I, which are switched at 4, are connected as shown in FIG.
1 4 Therefore, the Hall voltages shown in Figure 4) to (B)...
・4 and the same figure) As shown in the diagram, the current level switching point of the coil current I, 〜, coincides with the zero-crossing point of the Hall voltage ・, 〜・4. do. For this reason, for example, the amplitude of the Hall voltage 4 may change due to an imbalance in the product sensitivity of the Hall elements H1, Hf, an imbalance in the DC potential of their voltage terminals, an imbalance in the Hall output waveform, etc. ) to (b), the flow angle of the coil current x4 does not change even if it becomes large as shown by the dashed dotted lines. The same applies to other coil currents.

Therefore, according to this embodiment, torque ripples, rotational irregularities, etc. due to the influence of variations in the Hall elements H1 and H2 do not occur, and compared to the logic processing type, noise is not generated. Further, the circuit can be configured more easily than the circuit in which FIG. 1 is added to equalize the output DO levels of the Hall elements.

In addition, what is shown in FIG. 3 is a transistor "1"1'
T0 is used in repeated saturation and cutoff states, while transistors T and T are connected to terminal 1r2.
It is used with its conductivity controlled by the speed error signal from 14. That is, the speed error signal line enters terminal 1 via the transistor "rl" via the resistor R6.

is supplied to turn on the transistor T1 rl
o r7 Therefore, the amount of current flowing through the transistors T and T which are turned on and off by the Hall voltage . . . 4 is controlled.
r4 In particular, one transistor "r2 '" controls the conductive layer tube of r4 (this is a trap), and the coil current I.

The amplitude of .about..times..times..times..times..times..times..times..times..times..times..times..times..times..times..times..times..times..times..times..times..times..times..times..times..times..times..times..times..times..times..times..times..times..times..times..times..times..

On the other hand, the torques generated by the coils L, -L4 are as shown in Fig. 4, σ) to ▪. For example, in the period O~-, the torque T generated in coil L, the torque generated in coil L, and the torque generated in coil L2 cancel each other out in opposite directions, and the torque generated in coil L2c, the torque generated in coil L〆, is i. 6. Note that during this period, as is clear from FIG. 4 (7), the product of the negative current and the negative magnetic flux becomes a positive torque. The resultant torque for the entire period of combining dolkuchi and ~'r4 shown in Fig. 4 σ) to) is as shown in the same figure.The resultant torque for the conventional electric motor shown in Fig. Figure (J)) It has a meeting that is twice as large as K.

This will be explained using a formula. The coil resistance of the 1-equivalent coil in the conventional electric motor shown in Figure 1 is expressed as the number of R turns. , power supply voltage t vO1 magnetic flux density or IB, motor input current I. The output torque! . Ha, Chi BMX o oo.

m B, 1. -1(1). Next, since other three-phase coils are connected in parallel to both terminals of the coil through which a large current flows in the motor of this embodiment shown in Fig. 3, the same coils as those of the conventional motor are used. In this case, the motor input resistance is , and the motor input current I is $10. The output torque T at this time can be expressed as τ-BNl 0 , (!) and (!) as T, -T 0 .

Next, the coil has the same weight (copper content) as the coil used in conventional motors, and the motor input current is also the same.
The torque of the electric motor of this example when The same motor coil resistance as in a conventional motor is ``1 (''
”O), the total length of the coil is tl, the cross-sectional area is 81, the number of turns is 1 blade, the total length of the coil with a conventional electric motor is 10, the cross-sectional area is 8n1, the number of turns is tM0, and the specific resistance is -, then it is 111°. shi, (8), (4 formula and Rlm-;R, yoshi,
s, Be.

becomes. Also, since the coil of the motor of this embodiment and the coil of the conventional motor have the same amount of copper, tls, -toao (6) holds true, and according to equations (5) and (6), 8°, 8. By erasing , we get Also, assuming that the number of turns is approximately proportional to the total length of the coil, it can be expressed as follows.

FIG. S shows a circuit diagram of another embodiment of the electric motor of the present invention, in which parts having the same functions as those in FIG. 3 are given the same numbers and symbols. In the same figure, the pace of the transistor "r2 is 1"21 to the collector of the transistor T ° through the resistor R10% transistor
The base of the y5 transistor is connected to the collector of the transistor T14 via the resistor R11 and the track 4 star PHI.
5 16 emitters are connected to a power supply v2 via a resistor "12", and emitters of transistors T1 and T2 are connected to a terminal 1 via a transistor "r21" and a resistor R8. The other configurations are similar to the circuit shown in FIG.

In the original case, the transistors Tr1 to Tr4 are repeatedly used in a saturated state and a fast-acting state, and the transistor Tr12 is used repeatedly.
8 is used to control the conductivity of the speed error signal from terminal 1, and is used to control the coil current.

The amplitude of ~x4 changes depending on the conduction state of the transistor "r2!l. The other operations are easily understood as shown in FIG. 3, so their explanation will be omitted.

In addition, in FIG. 3, transistors Tr2' Tr4 t
- The transistors T and T are operated repeatedly in a saturated state and a fast-acting state, and the conduction state rl of the transistors T and T is controlled by a speed error signal.
l”! state may be controlled.

In addition, in FIG. 5, the transistor "r2!l" which operates as a variable impedance element is replaced by the transistor "1.".

It may be provided on the 'r□ side.

As described above, in the DC brushless motor according to the present invention, one ends of the first and second stator windings are connected to one end of the first switching element, and one ends of the third and fourth stator windings are connected to one end of the first switching element. the second
the other ends of the first and fourth stator windings are connected to one end of a third switching element; one end of the fourth switching element is connected to one end of the fourth switching element, and the other ends of the first and second switching elements and the other ends of the third and fourth switching elements are connected directly or through an impedance element between the power supply terminals. The output signal of the first position detector is used to control the opening and closing of the first and second switching elements, and the output signal of the second position detector is used to control the opening and closing of the third and fourth switching elements.
Since the switching element 0WII4 is connected to perform the closing control, both the switching element connected to the 10th position detector and the switching element connected to the 20th position detector are always on), that is. , which of the third and fourth switching elements is turned on when either of the first and 1I42 switching elements is turned on,
While a large current flows through the stator winding of one of the phases,
The current of the first current flows through the stator windings of the other three phases, and the current level switching point of the current flowing through the stator windings coincides with the zero-crossing point of the output signal of the position detector. ,
For this reason, when a Hall element is used as a position detector, the output of the position detector may be affected by an unbalance in the product sensitivity of the Hall element, an unbalance in the DC potential of its voltage terminal, an unbalance in the Hall output waveform, etc. Even if the amplitude of the signal fluctuates compared to the normal amplitude, the flow angle of the stator winding current will not be affected by it, and therefore torque ripples or uneven rotation will not occur, and the position Compared to the type that digitally escapes the output signal of the detector, there is no noise generation, and there is no need to equalize the product sensitivity of the Hall elements, and a circuit is added to equalize the DC level of the voltage terminal of the Hall element. The circuit can be configured easily and inexpensively compared to the conventional one, and furthermore, the other three-phase stator windings are connected in parallel to both terminals of the stator winding through which the large current flows. It has the advantage of being able to obtain a combined torque that is twice as much as that of conventional electric motors.

[Brief explanation of the drawing]

1 and 2) to (J)Fi, respectively, a circuit diagram of an example of a conventional circuit, a signal for explaining its operation, a torque waveform diagram, and a third
Figures 4 and 4) are a circuit diagram of an embodiment of the electric motor of the present invention, and signals and torque waveforms for explaining its operation, and Figure S is a circuit diagram of an example of the electric motor of the present invention. . 11, H,...Hall element, TJ1-L4...Stator coil, τ~! rl rfo ” “r21 ”” transistor, v
l, v,...Power supply, 1...Speed error signal input terminal.

Claims (3)

[Claims] (1) The output signal of the magnetic pole position of the rotor including the permanent magnet is approximately (-+ng) radian (rl -0, ±1) in electrical angle.
．． ±2. ...), and a plurality of switching elements respectively connected to the first to fourth stator windings of the adjacent respective ones are detected by the eighteenth and second position detectors having a phase difference of The opening/closing is controlled by the output signals of the first and second position detectors, and current is sequentially passed through the first to fourth stator windings to the rotor. one end of the second stator winding is connected to one end of the first switching element; one end of the third and fourth stator windings is connected to one end of the second switching element; The other end of the fourth stator winding is connected to one end of the third switching element, the other ends of the second and third stator windings are connected to one end of the fourth switching element, and the other end of the fourth stator winding is connected to one end of the third switching element. 1st and 2nd
The other end of the switching element and the other ends of the lss and the fourth switching element are connected between the power supply terminals directly or via a Hiro impedance element, and the output signal of the first position detector is used to connect the first and a second switching element, and is connected to the output signal of the second position detector so as to control opening and closing of the third and fourth switching elements. DC brushless electric motor. (2) Either the pair of the first and second switching elements or the pair of the third and fourth switching elements repeatedly operates in a saturated state and a fast-acting state, and the switching element 2. The DC brushless motor according to claim 1, wherein the other pair is an element that operates as a variable impedance element whose conduction state is controlled by a speed error signal of the rotor. (3) Adjust the magnetic pole position of the rotor, including the permanent magnets, to
, ±1. ±2. ...) with a phase difference of
A plurality of switching elements connected to the It to fourth stator windings are detected by a position detector, and have a phase difference of approximately (-+nπ) radians in electrical angle between adjacent switching elements. In a direct current brushless motor that drives a rotor by sequentially passing current through the first to fourth stator windings by controlling opening and closing using the output signals of the first and second position detectors,
and one end of the second stator winding is connected to one end of the first switching element, one ends of the third and fourth stator windings are connected to one end of the second switching element, and the first and the other end of the fourth stator winding is connected to one end of the third switching element; the other ends of the second and third stator windings are connected to one end of the fourth switching element; The other end of either the pair of first and second switching elements or the pair of SS and fourth switching element is directly connected to one end of the power supply terminal, and the other end of the other pair of switching elements is connected directly to one end of the power supply terminal. The other end is connected to the other end of the power supply terminal via a variable impedance element whose conduction state is controlled by the speed error signal of the rotor, and the output signal of the first position detector is connected to the first and The opening/closing control of the second switching element is performed, and the output signal of the second position detector is used to control the opening/closing of the third switching element.
and a fourth switching element connected to control opening and closing.