JP2004072903A - Brushless motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brushless motor wherein substitution can be easily carried out without changing a revolution number detection circuit in equipment incorporating a brushless motor, by outputting a revolution number pulse with the same number of pulses as a motor whose number of rotor poles is 8 even if the number of rotor poles is 10, and reduction in noise and vibration is accomplished. <P>SOLUTION: A revolution number pulse signal frequency conversion circuit 17 is provided. Thus, even if the number of rotor poles is 10, the revolution number pulse signal with 4 pulses or 12 pulses per revolution is outputted. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a brushless motor that realizes low noise and low vibration, and an electric device or an automobile (hereinafter, device) such as an air conditioner, an air purifier, or a water heater equipped with the brushless motor.
[0002]
[Prior art]
2. Description of the Related Art In recent years, brushless motors are used for a wide range of applications because they have a long life and are maintenance-free, and low noise and low vibration are required. The number of rotor poles of a conventional brushless motor is generally 4 or 8, and a portable type device has a motor and a control circuit integrally formed. On the other hand, in a stationary type device, the motor and the control circuit are configured separately, and the control circuit is provided on the device side.
[0003]
Here, a general brushless motor will be described. As shown in FIG. 7, a rotor 71 provided with eight north and south poles alternately in the circumferential direction, a stator 73 connected to 12 slots 72 in three phases, and three-phase full-wave energization of the stator 73. , A position detection element 75a to 75c for detecting the position of the rotor 71, a position detection signal processing circuit 76 for processing an output signal of the position detection element 75, and a position detection signal processing circuit 76. The rotation speed pulse signal output circuit 77 outputs a rotation speed pulse signal to the outside.
[0004]
Since the rotation pulse signal has eight rotor poles, when the output signal of one position detection element 75 is output as it is, four pulses per rotation and the output signals of three position detection elements 75 are combined. In the case of output, there are 12 pulses per rotation. In a device equipped with a brushless motor that outputs a rotation speed pulse signal, the rotation speed pulse signal is used for speed detection of the brushless motor.
[0005]
[Problems to be solved by the invention]
However, as a solution to the demand for low noise and low vibration for the brushless motor, a brushless motor including a stator having 10 rotor poles and 12 three-phase windings in slots has been proposed.
[0006]
FIG. 8 shows a method of generating the rotation number pulse signal. When the output signal 75ao of one position detection element 75a is output as it is through the position detection signal processing circuit 76, the rotation number pulse signal of 5 pulses per rotation is obtained. It becomes. Similarly, when the output signals 75ao to 75co of the three position detection elements 75a to 75c are combined and output by the position detection signal processing circuit 76, a rotation number pulse signal of 15 pulses per rotation is obtained.
[0007]
Generally, as for the rotation speed pulse signal, if the number of rotor poles is n, n / 2 pulses or 3n / 2 pulses are obtained per rotation.
[0008]
For this reason, when a 10-pole rotor brushless motor is connected to the conventional 8-pole rotor brushless motor control circuit, the 10-pole rotor brushless motor outputs a rotation number pulse signal at 5 pulses or 15 pulses per rotation, respectively. For this reason, there is a problem that even if the rotation speed is the same as that of the 8-pole rotor brushless motor, it is detected as 1.25 times the rotation speed.
[0009]
Therefore, in a device equipped with these brushless motors, when a brushless motor having 8 and 10 rotor poles is used in common, there is a problem that the rotation speed detection circuit in the device must be changed.
[0010]
The present invention solves such a conventional problem, and outputs a rotation number pulse signal having the same number of pulses as a motor having eight rotor poles even when the number of rotor poles is ten, so that a brushless motor can be used. An object of the present invention is to provide a brushless motor that can be easily replaced without changing a rotation speed detection circuit in a device to be mounted, and that realizes low noise and low vibration.
[0011]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is provided with a rotation speed pulse signal frequency conversion circuit. Even when the number of rotor poles is 10, a rotation number pulse signal of 4 pulses or 12 pulses per rotation is output.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
In order to solve the above-described problems, the present invention provides a rotor having a plurality of poles, a stator having a plurality of slots, and three-phase connected to the slots, and a drive circuit for applying three-phase full-wave current to the stator. A position detection element for detecting the position of the rotor, a position detection signal processing circuit for processing an output signal of the position detection element, and a frequency of a rotation speed pulse signal generated by the position detection signal processing circuit. In a brushless motor including a rotation speed pulse signal frequency conversion circuit and a rotation speed pulse signal output circuit that outputs a rotation speed pulse signal frequency-converted by the rotation speed pulse signal frequency conversion circuit, when the number of rotor poles is n, It outputs a rotation number pulse signal of 0.8 n / 2 pulses or 3 × 0.8 n / 2 pulses per rotation.
[0013]
The ratio between the number of poles of the rotor and the number of slots of the stator is 10:12.
[0014]
When the number of poles of the rotor is 10, the result is obtained by using signal processing means, output means, and the like by (n-2) / 2 pulses or 3 (n-2) / 2 pulses per rotation or a similar calculation method. The rotation number pulse signal of 4 pulses or 12 pulses per rotation, which is the same as when the number of poles of the rotor is 8, is output.
[0015]
The width of the drive circuit is 135 to 180 electrical degrees.
[0016]
Further, the driving circuit is a sine wave driving circuit.
[0017]
Further, the energization width of the drive circuit is set to 150 ° in electrical angle.
[0018]
Further, the energizing width of the drive circuit is set to 150 ° in electrical angle, the magnitude of the applied voltage in the first energizing period is set to the first value, and the magnitude of the applied voltage in the second energizing period is set to the second value. It is.
[0019]
The ratio between the first value and the second value is sin (π / 3): 1 (approximately 0.866: 1).
[0020]
In addition, the motor includes a drive circuit, a position detection element, a position detection signal processing circuit, a rotation speed pulse signal frequency conversion circuit, and a rotation speed pulse signal output circuit.
[0021]
The rotor has an IPM structure with a built-in magnet.
[0022]
In addition, the present invention is an electric device equipped with these brushless motors.
[0023]
Further, the present invention is an automobile equipped with these brushless motors.
[0024]
As described above, according to the present invention, a brushless motor that realizes low noise and low vibration can be easily replaced from a conventional product without changing a rotation speed detection circuit in a device in which the brushless motor is mounted.
[0025]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0026]
(Example 1)
FIG. 1 shows a rotor 11 having 10 poles, a stator 13 provided with windings 12 a in twelve slots 12, connected in three phases, a drive circuit 14 for applying three-phase full-wave current to the stator 13, Position detecting elements 15a to 15c for detecting positions, a position detecting signal processing circuit 16 for processing output signals 15ao to 15co of the position detecting elements 15a to 15c, and a rotation number pulse signal 16ao generated by the position detecting signal processing circuit 16 , 16bo, and a rotation speed pulse signal output circuit 18 for outputting the rotation speed pulse signals 17ao, 17bo frequency-converted by the rotation speed pulse signal frequency conversion circuit 17 to the outside. 1 shows a schematic configuration of a brushless motor.
[0027]
As shown in FIG. 2, the output signals 15ao to 15co of the position detecting elements 15a to 15c are signals of 5 pulses per rotation, each phase being shifted by an electrical angle of 120 °. The output signals 15ao to 15co are subjected to signal processing by the position detection signal processing circuit 16 to output a signal 15ao of 5 pulses per rotation or a signal 15bo of 15 pulses per rotation. The signal 15ao or the signal 15bo is frequency-converted by the rotation speed pulse signal frequency conversion circuit 17, and a signal 17ao of 4 pulses per rotation or a signal 17bo of 12 pulses per rotation is output. The signal 17ao or the signal 17bo is output to the outside through the rotation speed pulse signal output circuit 18. It goes without saying that the frequency conversion by the rotation speed pulse signal frequency conversion circuit 17 can be freely selected, and no conversion is performed in the case of a conventional 4-pole rotor or 8-pole rotor.
[0028]
In the brushless motor in which the ratio of the number of rotor poles to the number of stator slots is 10:12, the line-to-line induced voltage can be approximated to a sine wave, torque pulsation can be suppressed, and low noise and low vibration can be achieved. It can be.
[0029]
Further, by setting the energization width of the drive circuit to 135 to 180 degrees in electrical angle, a change in current flowing through the coil is reduced due to the three-phase energization period at the time of phase switching, torque pulsation is suppressed, and noise is further reduced.・ Low vibration can be achieved.
[0030]
Further, by setting the energization width to an electrical angle of 150 °, the magnitude of the applied voltage in the first energization period to the first value, and the magnitude of the applied voltage in the second energization period to the second value, the applied voltage waveform Can be made into a sine wave shape, and the current flowing through each phase coil approaches a sine wave, so that the noise and vibration can be further reduced.
[0031]
In particular, the first energization period is an electrical angle of 30 °, which is generated at intervals of 30 °, and the ratio of the first value to the second value is sin (π / 3): 1 (approximately 0.866: 1). ), The applied voltage waveform can be made into a sine wave shape with high accuracy, and the current waveform of each phase coil can be made closer to a sine wave, so that further low noise and low vibration can be achieved.
[0032]
Furthermore, if this drive circuit is a sine wave drive circuit, the current flowing through the coil will be closest to the sine wave, and the noise and vibration can be further reduced.
[0033]
(Example 2)
In the brushless motor of the second embodiment, the drive circuit of the first embodiment is a sine wave drive circuit.
[0034]
3, a brushless motor includes a sine wave drive circuit 24, position detection elements 25a to 25c for detecting the position of the rotor 21, a position detection signal processing circuit 26, a rotation speed pulse signal frequency conversion circuit 27, and a rotation speed pulse. Since the signal output circuit 28 is built in the motor, the size of the motor can be reduced by integrating the motor and the circuit.
[0035]
In addition, when a ten-pole rotor having an IPM rotor structure in which the magnet 21a is built in the rotor core 21b is used, high efficiency can be realized in addition to low noise and low vibration.
[0036]
(Example 3)
Third Embodiment A third embodiment is an example in which the brushless motor of the present invention is mounted on a room air conditioner indoor unit and an outdoor unit.
[0037]
In FIG. 4, a cross flow fan 42 is attached to a brushless motor 41 for blowing the indoor unit, and the heat exchanger 44 of the indoor unit 43 is cooled. Further, a propeller fan 46 is attached to the brushless motor 45 for blowing the outdoor unit, and the heat exchanger 48 of the outdoor unit 47 is cooled. During operation of the room air conditioner, these brushless fan motors are driven to rotate.
[0038]
By using the present invention for a fan motor of a room air conditioner as described above, there is an effect of suppressing resonance of a fan and a device body during operation of the room air conditioner, and low noise and low vibration can be realized.
[0039]
(Example 4)
In the fourth embodiment, the brushless motor of the present invention is mounted on a water heater, and is mounted on a blower fan motor for supplying air required for combustion.
[0040]
In FIG. 5, a sirocco fan 52 is attached to a fan motor for blowing air 51, housed in a casing 53, and blows air from a discharge port 54 to a combustion pot 55 of a water heater body 56. It has the effect of suppressing the resonance of the fan and the equipment body during the operation of the water heater, and can achieve low noise and low vibration.
[0041]
(Example 5)
In the fifth embodiment, the brushless motor of the present invention is mounted on an air purifier, and is mounted on a blower fan motor for supplying purified air.
[0042]
In FIG. 6, a sirocco fan 62 is attached to the air purifier blower motor 61 as shown in an internal sectional view 64 of the air purifier main body 63. This also has the effect of suppressing the resonance of the fan and the device main body during the operation of the air purifier, thereby realizing low noise and low vibration.
[0043]
The present invention is not limited to the above-described embodiment. Other applications include, for example, a fan motor for an air conditioner for an automobile that requires quietness of an indoor space, a fan motor for cooling a radiator, and an electric bicycle. It can also be mounted as a drive motor.
[0044]
【The invention's effect】
As is apparent from the above embodiment, according to the first aspect of the present invention, even if the number of rotor poles is 10, the number of rotation pulse signals of the same number as that of the motor having the number of rotor poles of 8 is output, so that the brushless It is possible to provide a brushless motor that can be easily replaced without changing a rotation speed detection circuit in a device on which the motor is mounted, and that achieves low noise and low vibration.
[0045]
Further, a brushless motor in which the ratio of the number of rotor poles to the number of stator slots is 2: 3 by setting the ratio of the number of rotor poles to the number of stator slots to 10:12 as in the second aspect of the present invention. Also, the line induced voltage can approximate a sine wave, torque pulsation can be suppressed, and low noise and low vibration can be achieved.
[0046]
Further, by changing the energization width of the drive circuit to an electrical angle of 135 to 180 [deg.] As in the invention according to claim 4, a change in current flowing through the coil is reduced due to the three-phase energization period at the time of phase switching. In addition, torque pulsation can be suppressed, and low noise and low vibration can be achieved.
[0047]
Further, when the drive circuit is a sine wave drive circuit as in the invention of claim 5, the current flowing through the coil can be approximated to a sine wave, and the ratio of the number of rotor poles to the number of status lots is 10: By setting to 12, the line induced voltage can be made closer to a sine wave, so that torque pulsation can be further suppressed and low noise and low vibration can be achieved.
[0048]
Further, by setting the energizing width of the drive circuit to 150 ° in electrical angle as in the invention of claim 6, the line induced voltage can be easily approximated to a sine wave, and the current flowing through the winding is reduced. Since the sine wave can be approximated, low noise and low vibration can be easily achieved.
[0049]
Further, as in the invention according to claim 7, the energization width of the drive circuit is set to 150 ° in electrical angle, the magnitude of the applied voltage in the first energization period is set to the first value, By setting the magnitude to the second value, the current flowing through the winding can be made closer to a sine wave, so that lower noise and lower vibration can be achieved.
[0050]
Further, when the ratio between the first value and the second value is sin (π / 3): 1 (approximately 0.866: 1) as in the invention described in claim 8, the 150 ° conduction The brushless motor with the lowest noise and vibration can be obtained.
[0051]
Further, as in the invention according to the tenth aspect, an IPM structure having a built-in magnet is provided, and by increasing the amount of magnetic flux of the magnet, high efficiency can be achieved in addition to low noise and low vibration.
[0052]
Furthermore, resonance of the electric device main body or the vehicle main body can be suppressed, and the device main body can also have low noise and low vibration.
[0053]
In this way, by providing the rotation speed pulse signal frequency conversion circuit, it is possible to easily replace the conventional product without changing the rotation speed detection circuit in the device equipped with the brushless motor, and to achieve low noise and low noise. A brushless motor capable of realizing vibration can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a brushless motor according to a first embodiment of the present invention; FIG. 2 is an explanatory diagram of a rotation pulse signal generation according to the first embodiment of the present invention; FIG. FIG. 4 is an explanatory view of application to a room air conditioner indoor unit and an outdoor unit according to a third embodiment of the present invention. FIG. 5 (a) is an explanatory view of a fan motor for blowing air in a fourth embodiment of the present invention. FIG. 6 (a) is an explanatory view of application to a water heater in a fourth embodiment of the present invention. FIG. 6 (a) is an explanatory view of application to an air purifier in a fifth embodiment of the present invention. FIG. 7 is a schematic configuration diagram of a conventional brushless motor. FIG. 8 is an explanatory diagram of a rotation pulse signal generation of the conventional brushless motor.
11, 21 Rotor 12 Slot 12a Winding 13 Stator 14 Drive circuit 15, 25 Position detecting element 16, 26 Position detecting signal processing circuit 17, 27 Revolution pulse signal frequency conversion circuit 18, 28 Revolution pulse signal output circuit 21a Magnet 24 Sine wave drive circuit

Claims (12)

A rotor having a plurality of magnets, a stator having a plurality of slots and being connected in three-phase to the slots, a drive circuit for applying three-phase full-wave current to the stator, and a position detecting element for detecting a position of the rotor. A position detection signal processing circuit that processes an output signal of the position detection element, a rotation number pulse signal frequency conversion circuit that converts the frequency of a rotation number pulse signal generated by the position detection signal processing circuit, and the rotation number pulse. In a brushless motor comprising a rotation speed pulse signal output circuit for outputting a rotation speed pulse signal frequency-converted by a signal frequency conversion circuit to the outside, when the number of rotor poles is n, 0.8n / 2 pulses or 3 rotations per rotation. A brushless motor that outputs a rotation number pulse signal of 0.8 n / 2 pulses. 2. The brushless motor according to claim 1, wherein a ratio of the number of poles of the rotor to the number of slots of the stator is 10:12. When the number of poles of the rotor is 10, signal processing means and output means using (n-2) / 2 pulses or 3 (n-2) / 2 pulses per rotation or a similar calculation method are used as a result. 3. The brushless motor according to claim 1, wherein a rotation number pulse signal of 4 pulses or 12 pulses per rotation is output as when the number of poles of the rotor is 8. 3. The brushless motor according to claim 1, wherein the drive circuit has an energization width of 135 to 180 degrees in electrical angle. 3. The brushless motor according to claim 1, wherein the drive circuit is a sine wave drive circuit. The brushless motor according to claim 1 or 2, wherein the energization width of the drive circuit is set to 150 electrical degrees. The energization width of the drive circuit is set to 150 ° in electrical angle, and two phase coils of each phase coil are in a voltage application state in the same direction, and the remaining one phase is in a voltage application state in the opposite direction (hereinafter referred to as a first energization state). The magnitude of the applied voltage in the period is set to a first value, and a period in which one phase is stopped except for the first energizing period and the other one phase is in a voltage application state in the opposite direction to each other (hereinafter referred to as a second energizing period). 3. The brushless motor according to claim 1, wherein the magnitude of the applied voltage during the period is set to a second value. 8. The brushless motor according to claim 7, wherein a ratio of the first value and the second value is sin (π / 3): 1 (approximately 0.866: 1). 9. The motor according to claim 1, wherein a drive circuit, a position detection element, a position detection signal processing circuit, a rotation speed pulse signal frequency conversion circuit, and a rotation speed pulse signal output circuit are built in the motor. A brushless motor according to any one of the preceding claims. The brushless motor according to any one of claims 1 to 9, wherein the rotor has an IPM structure including a magnet. An electric device equipped with the brushless motor according to any one of claims 1 to 10. An automobile equipped with the brushless motor according to any one of claims 1 to 10.

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