JPH0767304B2 - Multi-phase energized brushless motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a multi-phase energization brushless motor such as a three-phase energization brushless motor, and particularly to a rotor position detection element having a small number of drive coils. The present invention relates to a multiphase energization type brushless motor capable of performing multiphase energization by means of a drive circuit.

SUMMARY OF THE INVENTION The present invention is, for example, in a multi-phase energization type brushless motor such as a three-phase energization type, in which two phase currents respectively applied to two drive coils are applied to another drive coil to be combined, It is possible to simplify the drive circuit by using the current for one phase.

[Prior Art] FIG. 8 shows a schematic circuit diagram of a conventional three-phase energization type brushless motor. Hall elements mounted on the stator 1,2,3
Generates a three-phase AC voltage having a phase difference of 120 degrees (electrical angle) with the rotation of a rotor in which N poles and S poles are alternately arranged. These signals are amplified in the voltage amplifying circuits 4, 5, 6 and then current-amplified in the current amplifying circuits 7, 8, 9. And the drive coils 10,1 attached to the stator
It is supplied to 1 and 12 as a three-phase AC power supply, and the rotor is driven. In the figure, Vs represents the power supply voltage of the Hall element.

FIG. 9 shows a schematic circuit diagram of the above-mentioned motor improved to reduce the price. In this motor, one Hall element is eliminated, and instead, the output voltages of the other two Hall elements 1 and 2 are combined by the signal combining circuit 13 to obtain the required three-phase voltage.

Further, there is an invention described in Japanese Patent Laid-Open No. 58-116088 in which the drive coil is delta-connected and operates with a single power source, but the structure of the Hall element and the drive circuit is shown in FIG. 8 or FIG. It is basically the same as

[Problems to be Solved by the Invention] In the conventional two-phase energization type brushless motor described at the beginning,
Three Hall elements and three sets of voltage amplifier circuits and current amplifier circuits for amplifying the output signals of each Hall element are required. Therefore, the material cost and the processing / assembly cost are high, and the motor is expensive.

The conventional three-set energizing brushless motor shown below has been improved in that the number of Hall elements required is reduced to two, but the drawback is that a new signal combining circuit must be provided. have.

An object of the present invention is to eliminate such drawbacks and provide a three-phase energization type brushless motor which operates with a simple drive circuit.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the multi-phase current-carrying brushless motor according to the first aspect of the present invention has drive coils for at least three phases, one end of which is commonly connected. Then, AC voltages having different phases are formed on the basis of the respective angular position detection signals of the plurality of rotor position detecting means for generating the angular position detection signals which change according to the angular position of the rotor, and the alternating voltage is applied to each drive coil for rotation. In a driven multi-phase energization brushless motor, the number of rotor position detecting means is at least one less than the number of drive coils, and at least one of the drive coils does not correspond to the rotor detecting means. To the drive coils for the phases, apply the AC voltage flowing through at least two drive coils among the other drive coils through the common connection point of the drive coils. It is characterized in that is connected to be driven by the AC voltage phase the synthesized AC voltage.

In the illustrated first embodiment of the present invention, the multi-phase energization type brushless motor has one of the drive coils for three phases, that is, the drive coil, as shown in FIG. Connect one end of coil 12 to the ground of the device. Currents for two phases obtained by amplifying the signals from the Hall elements 1 and 2 are supplied to the other two drive coils 10 and 11 by the current amplifier circuits 7 and 8. In the second embodiment of the present invention, the multi-phase energization type brushless motor has a constant voltage source for generating a constant voltage, and one end of the drive coil 12 is connected to this voltage source. Further, it has a drive circuit for applying a predetermined AC voltage having the voltage of the voltage source as a center voltage to the other two drive coils.

According to a second aspect of the present invention, a first angular position detection signal is generated by detecting angular positions of the first, second and third drive coils, one ends of which are commonly connected, and the rotor. A second rotor position detecting means and a second rotor position detecting means which are arranged with a predetermined electrical angle offset with respect to the first rotor position detecting means and which have a predetermined phase difference with respect to the phase of the first angular position detection signal; Second rotor position detecting means for generating an angular position detection signal of the first rotor, and a first drive having a first phase according to the first angular position detecting signal generated by the first rotor position detecting means. A first coil driving means for forming a current to drive the first coil; and a first coil driving means having a second phase according to a second angular position detection signal generated by the second rotor position detecting means. Forming a second drive current to drive the second drive coil Second coil driving means, the first phase driving current of the first coil driving means and the second phase driving current of the second coil driving means are directly supplied to the third driving coil. And a third coil drive means for driving the third drive coil by forming a third drive current having a third phase which is a combination of the first phase and the second phase. It is characterized by having done.

[Operation] According to the first and second aspects of the present invention, at least one of the drive coils of the multi-phase energization brushless motor is used.
Each of the drive coils forms an AC voltage or drive current of a corresponding phase by combining drive currents of other phases. That is, in the multi-phase energization brushless motor according to the first embodiment of the present invention, the current supplied to the drive coils 10 and 11 is
It flows into the drive coil 12 through the common connection point of the drive coils 10, 11 and 12 for three phases, and is combined. This allows the drive coil
The current for another phase required for 12 is obtained, and the motor is driven. In addition, the multi-phase energization type brushless motor according to the second embodiment of the present invention is equivalent to the first invention in terms of alternating current, and therefore, by supplying current for two phases to the drive coil,
Similarly, the current for another phase is obtained and the motor is driven.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings.

Example 1 First, an example of the first invention will be described. As shown in FIG. 1, the three-phase current-carrying brushless motor of this embodiment has Hall elements 1 and 2 mounted on the stator, voltage amplification circuits 4,5 and current amplification circuits 7 and 4 for amplifying the outputs of these Hall elements. 8,
The drive coils 10, 11 and 12 are attached to the stator. The Hall elements 1 and 2 function as rotor position detecting means, and are arranged at an electrical angle of 120 ° (a position offset by a mechanical angle of 40 ° in the illustrated embodiment). This Hall element 1,2 and drive coil 10,11,1
2 is the substrate 1 as shown in the schematic plan view of the stator in FIG.
It is mounted on 4 and constitutes the stator. on the other hand,
As shown in the schematic plan view of FIG. 3, the rotor is magnetized so that N poles and S poles are alternately arranged in the circumferential direction.

Next, the operation will be described. Due to the rotation of the rotor shown in FIG. 3, the Hall elements 1 and 2 are different in phase from each other by 120 ° as angle detection signals according to the angular position of the rotor.
Generate AC voltage for each phase. These are the voltage amplification circuit 4,
5 and the drive coil amplified by the current amplifier circuits 7 and 8
It is supplied to 10 and 11 as drive currents with different phases of 120 °. The current flowing into the drive coils 10 and 11 flows into the drive coil 12 and is synthesized because one end of the drive coil 12 is connected to the ground. That is, the phases of the currents i ₁ and i ₂ flowing through the drive coils 10 and 11 are 120 ° out of phase as described above, which can be expressed as follows.

i ₁ = f (0 °) i ₂ = f (120 °) As shown in FIG. 1, three currents flow into the common connection point of the drive coils 10, 11 and 12, so that i ₁ + i ₂ + i ₃ = 0 holds. Therefore, the current i ₃ flowing through the drive coil 12 is given by the following equation.

i ₃ = − (i ₁ + i ₂ ) = − (f (0 °) + f (120 °)) The combined current is i ₁ = 240 ° out of phase, i ₃ = f (240 Therefore, the required three-phase current is supplied to the drive coil, and the rotor is driven.

Next, what kind of voltage should be applied to the drive coils 10 and 11 in order to pass such a current through the drive coils will be described in detail below. The output voltage of the current amplifier circuit 7 is V ₁ , the output voltage of the current amplifier circuit 8 is V ₂ , and the voltage at the common connection point of the drive coils is V (see FIG. 1). And
Find V ₁ and V ₂ required to obtain the currents i ₁ , i ₂ , and i ₃ as expressed by the following equation.

i ₁ = sin θ i ₂ = sin (θ + 120 °) i ₃ = sin (θ + 240 °) where θ represents a phase angle.

From the circuit of the drive coil unit shown in FIG. 1, the following equation is established.

V ₁ −V (= jωLi ₁ ) = jωL sin θ (1) V ₂ −V (= jωLi ₂ ) = jωLsin (θ + 120 °) (2) O−V (= jωLi ₃ ) = jωL sin (θ + 240 °)… ( 3) where ω is the angular frequency, L is the inductance of the drive coil, and j = 1.

From the formula (1) -the formula (3), V ₁ = jωL {sin θ−sin (θ + 240 °)} = jωL {2cos (θ + 120 °) sin (−120 °)} = jωL sin (θ + 30 °) ∴V ₁ = jωLsin (Θ + 30 °) (4) From formula (2)-(3), V ₂ = jωL {sin (θ + 120 °) -sin (θ + 240 °)} = jωL {2cos (θ + 180 °) sin (-60 °) } = JωLsin (θ + 90 °) ∴V ₂ = jωLsin (θ + 90 °) (5) V ₂ = jωL {-sin (θ + 30 ° + 240 °)}) ...
(6) That is, the drive coils 10, 11 and 12 are applied to the drive coils 10 and 11 by applying the voltages represented by the formulas (4) and (5) (or (6)), respectively. In addition, it is possible to pass the three-phase currents that are deviated by 120 ° necessary for the rotation of the motor.

In this embodiment, by appropriately adjusting the distance between the Hall elements 1 and 2 attached to the substrate 14 shown in FIG. 2, a voltage having the above-mentioned phase difference is obtained and these are amplified. Supplying to the drive coil.

FIG. 3 shows a detailed circuit diagram of this embodiment. The voltage amplifier circuit 4 is composed of an operational amplifier A, resistors R1 and R2, and a capacitor C, and the current amplifier circuit 7 includes transistors TR1 and TR.
It is composed of two. The voltage amplification circuit 5 and the current amplification circuit 8 have the same configuration. In the figure, Vs represents the power supply voltage of the Hall element, and + V, -V represent the power supply voltage of the current amplifier circuit.

Although the rotor has six magnetic poles in this embodiment, the number of poles is larger than this, and for example, a rotor having 10 poles can be used as shown in FIG. In this case, as shown in FIG. 5, the stator is composed of six drive coils, and every two coils are combined to form a drive coil for one phase.

Embodiment 2 An embodiment of the second invention will be described. As shown in FIG. 7, in this embodiment, one end of the drive coil 12 is connected not to the ground but to the connection point of the zener diodes 15 and 16, that is, the potential point having a voltage half the power supply voltage Vcc.
Further, the drive circuits 17 and 18 apply a predetermined AC voltage having a center voltage of 1/2 Vcc to the drive coils 10 and 11. With such a configuration, AC is equivalent to the case of the first embodiment, and the motor can be rotated only by supplying the current for two phases to the drive coil. In this case, since a negative (or positive) power supply is unnecessary, it is possible to drive the motor with a single power supply.

[Effects of the Invention] As described above, in the three-phase energization type brushless motor of the present invention, the currents for the two phases respectively supplied to the two drive coils are supplied to the other drive coil to be combined with each other. The current is for one phase. That is, the currents supplied to the drive coils for the three phases can be obtained by the hall elements and the drive circuits for the two phases. Therefore, the drive circuit can be simplified and the price of the three-phase energization brushless motor can be reduced.

Further, a motor in which one end of the drive coil is connected to a potential point having a voltage half the power supply voltage operates with a single power supply, and therefore the motor can be easily driven.

Although the present invention has been described by taking the three-phase energization type brushless motor as an example in the above specific embodiments, the present invention is not limited to the three-phase energization type brushless motor shown in the embodiments. Any multi-phase energized brushless motor,
For example, it can be applied to a brushless motor such as a 4-phase energization type or a 6-phase energization type.

[Brief description of drawings]

FIG. 1 is a schematic circuit diagram showing an embodiment of the first invention, FIG. 2 is a schematic plan view showing a stator of the same embodiment, FIG. 3 is a schematic plan view showing a rotor of the same embodiment, and FIG. Is a detailed circuit diagram showing the same embodiment, FIG. 5 is a schematic plan view showing a stator of another embodiment of the first invention, FIG. 6 is a schematic plan view showing a rotor of the same embodiment, and FIG. FIG. 8 is a schematic circuit diagram showing an embodiment of the second invention, FIG. 8 is a schematic circuit diagram showing a conventional three-phase energization type brushless motor, and FIG. 9 is a schematic circuit diagram showing another conventional example. 1,2 ... Hall element, 4,5 ... voltage amplification circuit, 7,8 ... current amplification circuit, 10,11, 12 ... drive coil, 14 ... substrate, 15,
16 …… Zener diode, 17,18 …… Drive circuit, A ……
Operational amplifier, R1 to R4 ... Resistance, C ... Capacitor, TR1,
TR2 …… Transistor.

Claims (2)

[Claims] 1. Angular position detection signals of a plurality of rotor position detection means having drive coils for at least three phases, one end of which is commonly connected, and which generate an angular position detection signal that changes according to the angular position of the rotor. In a multi-phase energization type brushless motor that is driven by rotating by applying alternating voltages having different phases to each other, the number of rotor position detection means is at least one less than the number of drive coils. In addition, in the drive coils for at least one phase among the drive coils that do not correspond to the rotor detecting means, at least two drive coils among other drive coils are connected to a common connection point of the drive coils. A multi-phase current-carrying brush, which is connected so as to be driven by an AC voltage which is applied via Less motor. 2. A first drive coil, a second drive coil, and a third drive coil, one ends of which are commonly connected, and a first rotor position detecting means for detecting an angular position of the rotor to generate a first angular position detection signal.
A second angular position detection signal is generated which is arranged with a predetermined electrical angle offset with respect to the first rotor position detection means and has a predetermined phase difference with respect to the phase of the first angular position detection signal. A second rotor position detecting means and a first drive current having a first phase in accordance with the first angular position detection signal generated by the first rotor position detecting means are formed to form the first drive current. Forming a second drive current having a second phase according to a second angular position detection signal generated by the second rotor position detection means and a first coil drive means for driving the coil A second coil drive means for driving the second drive coil; a first phase drive current of the first coil drive means and a second phase drive current of the second coil drive means. By directly supplying to the third drive coil, the first phase and Multi-phase energization characterized by being configured by a third coil driving means for driving the third drive coil by forming a third drive current having a third phase which is a combination of phase phases. Type brushless motor.