JP2004040918A - Brushless DC motor - Google Patents

Abstract

A CPU (Central Processing Unit) of a personal computer or the like has been improved in performance year by year, and the heat generation of the CPU has been greatly increased with the performance improvement. In the motor, the current that can be passed through the motor winding is limited by the current capability and allowable loss of the driver IC that energizes the motor winding, and the driving method that drives the motor, and the CPU is cooled. The output of the brushless DC motor is becoming insufficient.
A full-wave drive system in which the phases of a motor winding 1 are two phases, the phase difference of the current flowing in each phase is 180 °, or the phase difference is zero, and the current flows in both directions of the motor winding 1. A brushless DC motor is used to increase the current that can flow through the motor to improve the motor output.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fan motor generally used widely, and more particularly to a brushless DC motor used for a fan motor used for cooling a CPU (central processing unit) of a notebook personal computer.
[0002]
The present invention relates to a fan motor used for cooling a CPU of a notebook personal computer, and more particularly to a brushless DC motor capable of improving the motor output.
[0003]
[Prior art]
Generally, a notebook type personal computer or the like is equipped with a fan motor for cooling the CPU, which is a functional component, because the CPU generates heat. As the fan motor, a brushless small DC fan motor using a magnet for the rotor and having a drive circuit has been used from the viewpoint of power saving, device space, and life.
[0004]
The fan motor has a single-phase (one-phase) single-phase (single-phase) drive system in which the motor winding is single-phase (single-phase) from the viewpoint of the efficiency and cost of the fan motor. Or a two-phase half-wave drive system in which the motor winding is two-phase and each phase is half-wave driven with a phase difference of 180 °.
[0005]
FIG. 8 is a circuit configuration diagram of a single-phase full-wave drive system which is a conventional brushless DC motor, and FIG. 12 is a timing chart of motor winding commutation of a single-phase full-wave drive system which is a conventional brushless DC motor. The single-phase motor winding is driven in full-wave so that the excitation torque of the motor winding is in a fixed direction. The circuit configuration of the fan motor of the single-phase full-wave drive system includes a rotor position detecting component 16 and one driver IC 18 that commutates the motor winding 17.
[0006]
As for the direction of the current, the direction from the beginning to the end of the winding of the motor winding is defined as a positive direction, and the reverse direction is defined as a negative direction.
[0007]
FIG. 9 is a circuit configuration diagram of a two-phase half-wave drive system which is a conventional brushless DC motor, and FIG. 13 is a timing chart of motor winding commutation of a two-phase half-wave drive system which is a conventional brushless DC motor. As shown in FIG. 13, in the two-phase half-wave drive system, the two-phase motor windings are half-wave driven with a phase difference of 180 ° so that the excitation torque of the motor windings is in a constant direction. Only the current is flowing. The circuit configuration of the fan motor of the two-phase half-wave drive system includes a rotor position detecting component 19 and a transistor 21 that commutates the motor winding 20.
[0008]
[Problems to be solved by the invention]
By the way, the performance of CPUs used in personal computers has been improving year by year, and the heat generation of CPUs has been greatly increased with the improvement in performance. Therefore, there is a demand for improving the cooling performance by improving the motor output of the fan motor that cools the CPU.
[0009]
However, in the single-phase full-wave driving method, the current that can be passed through the motor winding is limited by the current capability and the allowable loss of the driver IC used, so that the motor output is limited. Further, in the two-phase half-wave driving method, the motor efficiency is lower than that in the single-phase full-wave driving method, so that the motor output is lower than that of the single-phase full-wave driving method.
[0010]
SUMMARY OF THE INVENTION An object of the present invention is to provide a brushless DC motor capable of greatly improving the motor output while paying attention to the conventional problems in the previous term.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a motor winding having two phases, a phase difference of 180 ° between currents flowing through each phase, or a phase difference of zero, and a current flowing in both directions of the motor winding. It is a two-phase full-wave drive type brushless DC motor.
[0012]
According to the present invention, one driver IC or several transistors are provided for each phase of a two-phase motor winding, and each phase is full-wave driven. The same current as above can be passed, and as a whole motor that combines two phases, it is possible to pass about twice the current of the single-phase full-wave drive system, and the brushless DC motor has greatly improved motor output Can be provided.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
The invention according to claim 1 of the present invention has a rotor as a rotating body, a printed circuit board having a rotor position detecting component, and a motor winding for rotating the rotor, and the number of phases of the motor winding is two. The brushless DC motor is characterized in that the phase of the current flowing in each phase is shifted by 180 ° and the current is applied to both phases of the motor winding by a full-wave drive system. This has the effect of increasing the current flowing through the motor and improving the motor output.
[0014]
The invention according to claim 2 of the present invention has a rotor as a rotating body, a printed circuit board having a rotor position detecting component, and a motor winding for rotating the rotor, and the number of phases of the motor winding is two. A brushless DC motor characterized by a full-wave drive system in which there is no phase difference between the currents flowing through the respective phases and the current flows in both directions of the motor windings. It has the effect of increasing the current flowing through the motor and improving the motor output.
[0015]
According to a third aspect of the present invention, in the brushless DC motor according to the first or second aspect, the printed circuit board has two driver ICs for driving the motor windings in full-wave. The driver ICs are arranged one for each phase of the motor winding, and each phase of the motor winding is driven by a single driver IC for full-wave driving. To increase the motor output.
[0016]
According to a fourth aspect of the present invention, in the brushless DC motor according to the first or second aspect, the printed circuit board includes several transistors for driving the motor windings in full-wave. It has a pre-driver IC that operates the transistor, and the transistor drives each phase of the motor winding full-wave. Using several transistors, the current flowing to the motor is increased, and the action of improving the motor output is achieved. Have.
[0017]
According to a fifth aspect of the present invention, in the brushless DC motor according to any one of the first to third aspects, the number of rotor position detecting components is one, and two driver ICs are operated by one rotor position detecting component. By doing so, the motor output can be improved, the number of parts can be reduced, and the brushless DC motor can be made inexpensive.
[0018]
According to a sixth aspect of the present invention, in the brushless DC motor according to the first, second, and fourth aspects, the number of rotor position detecting components is one, and the pre-driver is provided by one rotor position detecting component. By operating the IC, the motor output can be improved, the number of components can be reduced, and the brushless DC motor can be manufactured at low cost.
[0019]
According to a seventh aspect of the present invention, in the brushless DC motor according to the first or second aspect, only one rotor position detecting component is provided, and each phase of the motor winding is BTL (balanced). In addition to the fact that it is driven by a transformer (less transformer), the motor output is improved, the torque ripple is reduced to reduce the noise from the motor, and the brushless DC motor is reduced in cost.
[0020]
According to an eighth aspect of the present invention, in the brushless DC motor according to any one of the first to seventh aspects, the motor winding is connected to a printed circuit board, and the motor winding is an even number of slots of two or more slots. The motor winding is wound so that the rotor rotates in the desired direction of rotation even if the motor winding and the printed circuit board are mounted by being rotated by 180 °, thereby increasing the productivity of the brushless DC motor. Has an action.
[0021]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0022]
(Embodiment 1)
FIG. 1 is a circuit configuration diagram of a brushless DC motor according to the first embodiment of the present invention. FIG. 10 is a brushless DC motor according to the first embodiment of the present invention in which a phase difference of a current flowing through each phase is 180 °. FIG. 11 is a timing chart of the motor winding commutation of the brushless DC motor according to the first embodiment of the present invention in which the phase difference of the current flowing through each phase is zero. .
[0023]
In the brushless DC motor according to the first embodiment, when the phases of the motor winding 1 are two phases and each phase is an A phase and a B phase, the phase difference between the currents flowing through the A phase and the B phase is 180 ° or The method of energizing the motor winding with a phase difference of zero is a full-wave drive system in which current flows in both directions of the motor winding.
[0024]
In FIG. 10, there is a phase difference of 180 ° between the induced voltage 27 of the phase A and the induced voltage 28 of the phase B. Therefore, the current 29 of the phase A and the current 30 of the phase B are supplied with a phase difference of 180 °. The phases generate the excitation torques 31, 32 in the same direction. The combined excitation torque of the A-phase excitation torque 31 and the B-phase excitation torque 32 is 33.
[0025]
In FIG. 11, since there is no phase difference between the induced voltage 27 of the A phase and the induced voltage 28 of the B phase, the current 29 of the A phase and the current 30 of the B phase are supplied with a phase difference of zero, and each phase is in the same direction. Generates exciting torque. The combined excitation torque of the A-phase excitation torque 31 and the B-phase excitation torque 32 is 33.
[0026]
Whether the phase difference between the A-phase induced voltage 27 and the B-phase induced voltage 28 is 180 ° or zero is dependent on how the motor winding is wound.
[0027]
As for the direction of the current, the direction from the beginning to the end of the winding of the motor winding is defined as a positive direction, and the opposite direction is defined as a negative direction.
[0028]
The driver IC 2 is arranged one for each of the A phase and the B phase, and drives each phase in full-wave. If the same driver IC as in the single-phase full-wave drive method is used, the same current as in the single-phase full-wave drive method can be applied to the current that can flow in one phase. It is possible to pass about twice the current of the system.
[0029]
As described above, in the first embodiment, the phase difference of the current flowing through each phase of the two-phase motor winding is set to 180 ° or the phase difference is set to zero, and the two driver ICs are used to perform full-wave driving. And the motor output can be improved.
[0030]
Note that the driver IC can be composed of a driver IC dedicated to motor driving, a power amplifier, an operational amplifier, and the like.
[0031]
(Embodiment 2)
FIG. 2 is a circuit configuration diagram of a brushless DC motor according to Embodiment 2 of the present invention. 2, the same components as those in FIG. 1 are denoted by the same reference numerals as in FIG.
[0032]
In the brushless DC motor according to the second embodiment, as shown in FIG. 2, the energization of the motor winding 1 is driven by full-wave driving by several transistors 5 and a pre-driver IC 6 for operating the several transistors 5. Since the phase difference of the current flowing through each phase of the motor winding 1 is set to 180 ° or the phase difference is set to zero and each phase is driven by full-wave, the current that can flow in one phase is the same as that of the single-phase full-wave driving method. Since the current can flow, it is possible to flow about twice the current of the single-phase full-wave drive system in the entire motor in which the two phases are combined.
[0033]
As described above, in the second embodiment, the phase difference of the current flowing in each phase of the two-phase motor winding is set to 180 ° or the phase difference is set to zero, and several transistors 5 and several transistors 5 are operated. By performing full-wave driving with the pre-driver IC 6 to be driven, the current flowing through the motor can be increased, and the motor output can be improved.
[0034]
The pre-driver IC can be constituted by a pre-driver IC dedicated to motor driving, a driver IC, a power amplifier, an operational amplifier, and the like.
[0035]
(Embodiment 3)
FIG. 3 is a circuit configuration diagram of a brushless DC motor according to Embodiment 3 of the present invention. In FIG. 3, the same members as those in FIG. 1 or FIG. 2 are denoted by the same reference numerals as in FIG. 1 or FIG.
[0036]
As shown in FIG. 3, the brushless DC motor according to the third embodiment has one rotor position detecting component 3 for detecting the position of the rotor, and one rotor position detecting component 3 operates two driver ICs 2. Therefore, the motor output can be improved and the brushless DC motor can be reduced in cost.
[0037]
Note that the driver IC can be composed of a driver IC dedicated to motor driving, a power amplifier, an operational amplifier, and the like.
[0038]
(Embodiment 4)
FIG. 4 is a circuit configuration diagram of a brushless DC motor according to Embodiment 4 of the present invention. 4, the same components as those in FIGS. 1 to 3 are given the same reference numerals as those in FIGS.
[0039]
As shown in FIG. 4, the brushless DC motor according to the fourth embodiment has one rotor position detecting component 3 for detecting the position of the rotor, and operates several transistors 5 with one rotor position detecting component 3. Since the pre-driver IC 6 is operated, the motor output can be improved and the device can be made inexpensive.
[0040]
The pre-driver IC can be constituted by a pre-driver IC dedicated to motor driving, a driver IC, a power amplifier, an operational amplifier, and the like.
[0041]
(Embodiment 5)
FIG. 5 is a circuit configuration diagram of a brushless DC motor according to Embodiment 5 of the present invention. 5, the same components as those in FIG. 1 are given the same reference numerals as in FIG.
[0042]
In the brushless DC motor according to the fifth embodiment, as shown in FIG. 5, each phase of the motor winding 1 is driven by two power amplifiers 7 and 8 in a BTL (balanced transformerless) manner. The phase difference of the current flowing through each phase is set to 180 °, or the phase difference is set to zero. When the BTL drive is performed, the torque ripple of the motor decreases, and the sound from the motor decreases. One hall element 9 is used as a rotor position detecting component, and one power amplifier 7 is operated by the hall element 9, and another power amplifier 8 is operated with the output waveform of the power amplifier 7. The voltage dividing resistor 12 divides the output voltage of the power amplifier 7 so as not to exceed the input voltage range of the power amplifier 8. When the BTL drive is performed, a current flows from the Hall element 9 to the feedback resistor 10 that determines the gain of the amplifier, so that the output of the Hall element 9 decreases. However, by using a single power amplifier operated by the Hall element 9, The decrease in the output of the Hall element 9 can be reduced.
[0043]
As described above, in the fifth embodiment, the output of the Hall element is small, the sound is small, the cost is low, and the motor output can be improved.
[0044]
Note that the feedback resistor 10 may be arranged inside the power amplifiers 7 and 8.
[0045]
(Embodiment 6)
FIG. 6 is a winding diagram of a brushless DC motor according to the sixth embodiment, and FIG. 7 is a stator diagram of a brushless DC motor in which a printed circuit board and a motor winding are integrated.
[0046]
The brushless DC motor according to the sixth embodiment has a motor winding wound around an iron core as shown in FIG. The A-phase and the B-phase are wound in the same direction with the winding start facing each other, and the A-phase and the B-phase are wound in the same direction with the winding ends facing each other. For example, if the winding start of the phase A is wound in the CW direction (clockwise) and the winding end is wound in the CCW direction (counterclockwise), the winding of the phase B is also wound in the CW direction and the winding end is wound in the CCW direction. By winding the motor winding in this way, even if the mounting position with the printed circuit board 15 on which the motor winding 13 is mounted is rotated by 180 °, the winding direction of the motor winding 13 does not change and the rotation direction of the rotor is intended. Rotation direction.
[0047]
Note that the winding of the motor winding may be such that the winding start is in the CCW direction and the winding end is in the CW direction.
[0048]
As described above, in the sixth embodiment, the mounting position of the motor winding 13 and the printed circuit board 15 can be set to a desired rotation direction even when the motor winding 13 and the printed circuit board 15 are mounted by being rotated by 180 °. In addition, the productivity of the brushless DC motor can be improved.
[0049]
Although the first to sixth embodiments are directed to a cooling fan motor for a notebook personal computer, the brushless DC motor of the present invention may be a fan motor used for cooling other electronic devices.
[0050]
In the sixth embodiment, the number of slots of the motor is four, but any number of slots may be used as long as the number of slots is even.
[0051]
In addition, the motor structure according to the first to fifth embodiments may be any type such as a circumferential facing type, a face facing type, a slotted type, a slotless type, a cored type, a coreless type, an inner rotor type and an outer rotor type. A motor structure may be used.
[0052]
【The invention's effect】
As is apparent from the above description, the present invention sets the number of phases of the motor winding to two, and the method of energizing the motor winding is such that the phase difference of the current flowing through each phase of the motor winding is 180 °, Alternatively, a full-wave drive system with zero phase difference and current flowing in both directions of the motor winding can greatly improve the motor output, and can provide a small and inexpensive brushless DC motor. The effect is great.
[Brief description of the drawings]
FIG. 1 is a circuit configuration diagram of a brushless DC motor according to a first embodiment of the present invention; FIG. 2 is a circuit configuration diagram of a brushless DC motor according to a second embodiment of the present invention; FIG. FIG. 4 is a circuit diagram of a brushless DC motor according to a fourth embodiment of the present invention. FIG. 5 is a circuit diagram of a brushless DC motor according to a fifth embodiment of the present invention. FIG. 6 is a winding diagram of a brushless DC motor according to a sixth embodiment of the present invention; FIG. 7 is a stator diagram of a brushless DC motor in which a printed circuit board and a motor winding are integrated; FIG. FIG. 9 is a circuit diagram of a single-phase full-wave drive system as a motor. FIG. 9 is a circuit diagram of a two-phase half-wave drive system as a conventional brushless DC motor. FIG. 10 is a circuit diagram of each phase according to the first embodiment of the present invention. Phase of the flowing current FIG. 11 is a timing chart of the motor winding commutation of the brushless DC motor in which the phase difference of the current flowing through each phase is zero according to the first embodiment of the present invention. Timing chart of current [FIG. 12] Timing chart of motor winding commutation of single-phase full-wave drive system which is a conventional brushless DC motor [FIG. 13] Motor winding of two-phase half-wave drive system which is a conventional brushless DC motor Timing chart of linear commutation [Explanation of symbols]
1 Motor winding 2 Driver IC
3 rotor position detecting component 4 bias resistor of rotor position detecting section 5 transistor 6 pre-driver IC
7, 8 Power amplifier 9 Hall element 10 Feedback resistance 11 Bias resistance of Hall element 12 Voltage dividing resistor 13 Motor winding 14 Iron core
15 Printed circuit board 16 Rotor position detecting component 17 Motor winding 18 Driver IC
Reference Signs List 19 rotor position detection component 20 motor winding 21 transistor 22 comparator 23 direction of A-phase current 24 direction of B-phase current 25 direction of current flow 26 direction of current flow 27 induced voltage of A phase 28 induction of B phase Voltage 29 A-phase current 30 B-phase current 31 A-phase excitation torque 32 B-phase excitation torque 33 Combined excitation torque of A-phase and B-phase 34 Induced voltage 35 Current 36 Exciting torque 37 A-phase induced voltage 38 B-phase Induced voltage 39 A-phase current 40 B-phase current 41 A-phase excitation torque 42 B-phase excitation torque 43 Combined excitation torque of A-phase and B-phase

Claims (8)

It has a rotor that is a rotating body, a printed circuit board having a rotor position detecting component, and a motor winding for rotating the rotor. The number of phases of the motor winding is two, and power is supplied to the motor winding. The brushless DC motor is characterized in that the method is a full-wave drive system in which a phase of a current flowing in each phase is shifted by 180 ° and the current flows in both directions of a motor winding. It has a rotor that is a rotating body, a printed circuit board having a rotor position detecting component, and a motor winding for rotating the rotor. The number of phases of the motor winding is two, and power is supplied to the motor winding. The brushless DC motor is characterized in that the method is a full-wave drive system in which there is no phase difference between currents flowing in each phase and the current flows in both directions of a motor winding. The printed circuit board has two driver ICs for driving the motor windings in full-wave, and the driver ICs are arranged one for each phase of the motor windings, and each phase of the motor windings is a driver. 3. The brushless DC motor according to claim 1, wherein the brushless DC motor is driven by a single IC. The printed circuit board has several transistors for driving the motor windings in full-wave and a pre-driver IC for operating the transistors, and the transistors drive each phase of the motor windings in full-wave. The brushless DC motor according to claim 1 or 2, wherein: The brushless DC motor according to any one of claims 1 to 3, wherein there is one rotor position detecting component, and one driver position detecting component operates the two driver ICs. 5. The brushless DC motor according to claim 1, wherein the rotor position detecting component is one, and the pre-driver IC is operated by one rotor position detecting component. The brushless DC motor according to any one of claims 1 to 3, wherein there is one rotor position detecting component, and each phase of the motor winding is driven by a BTL (balanced transformerless). The motor winding is connected to a printed circuit board, and the motor winding has an even number of slots of two or more slots, and even if the motor winding and the printed circuit board are mounted by being rotated by 180 °, The brushless DC motor according to any one of claims 1 to 7, wherein the motor winding is wound so that the rotor rotates in a target rotation direction.

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