JP4158448B2 - Brushless motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a brushless motor that realizes low noise and low vibration, and an electric device or automobile (hereinafter, device) such as an air conditioner, an air purifier, or a water heater equipped with the brushless motor.
[0002]
[Prior art]
In recent years, brushless motors have been 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 having eight N poles and S poles alternately in the circumferential direction, a stator 73 connected in three phases to twelve slots 72, and a three-phase full-wave energization to the stator 73 Generated by the drive circuit 74 for performing position detection, the position detection elements 75a to 75c for detecting the position of the rotor 71, the position detection signal processing circuit 76 for processing the output signal of the position detection element 75, and the 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 speed pulse signal has 8 rotor poles, when the output signal of one position detection element 75 is output as it is, 4 pulses per rotation and the output signal of three position detection elements 75 are synthesized. When outputting, there are 12 pulses per revolution. In a device equipped with a brushless motor that outputs these rotational speed pulse signals, this rotational speed pulse signal is used for speed detection of the brushless motor.
[0005]
[Problems to be solved by the invention]
However, a brushless motor having a rotor pole number of 10 and a stator having 12 three-phase windings in a slot has been proposed as a solution to the demand for low noise and low vibration for the brushless motor.
[0006]
FIG. 8 shows a method of generating the rotation speed pulse signal. When the output signal 75ao of one position detection element 75a is directly output through the position detection signal processing circuit 76, the rotation speed pulse signal of 5 pulses per rotation is obtained. It becomes. Similarly, when the output signals 75ao to 75co of the three position detecting elements 75a to 75c are combined and output by the position detection signal processing circuit 76, a rotation speed pulse signal of 15 pulses per rotation is obtained.
[0007]
In general, an n / 2 pulse or a 3n / 2 pulse per rotation is obtained from the rotation number pulse signal where n is the number of rotor poles.
[0008]
Therefore, when a 10-pole rotor brushless motor is connected to a control circuit for a conventional 8-pole rotor brushless motor, the 10-pole rotor brushless motor outputs a rotation speed pulse signal of 5 pulses or 15 pulses per rotation, respectively. Therefore, there is a problem that even if the rotational speed is the same as that of an 8-pole rotor brushless motor, the rotational speed is detected as 1.25 times.
[0009]
Therefore, in devices equipped with these brushless motors, when a brushless motor having 8 and 10 rotor poles is shared, there has been a problem that the rotational speed detection circuit in the device must be changed.
[0010]
The present invention solves such a conventional problem, and even if the number of rotor poles is 10, a brushless motor is produced by outputting a rotation speed pulse signal having the same number of pulses as that of a motor having 8 rotor poles. It is an object of the present invention to provide a brushless motor that can be easily replaced without changing the rotational speed detection circuit in the mounted device and 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 if the number of rotor poles is 10, a rotation speed pulse signal of 4 pulses or 12 pulses per rotation is output.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
In order to solve the above-described problems, the present invention provides a rotor having a plurality of magnets, a stator having a plurality of slots and three-phase connected to the slots, and a drive circuit for conducting 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 rotation for converting the frequency of the rotational speed pulse signal generated by the position detection signal processing circuit In a brushless motor comprising a number pulse signal frequency conversion circuit and a rotation number pulse signal output circuit that outputs the rotation number pulse signal frequency-converted by the rotation number pulse signal frequency conversion circuit to the outside,
Even if the number of slots is the same and the number of rotor poles is different, the number of revolutions is selected by the revolution number pulse signal frequency conversion circuit so that the number of pulses per revolution of the motor becomes equal. A brushless motor that outputs a pulse signal .
[0013]
Further, even if the ratio between the number of rotor poles and the number of stator slots is 10:12 , a rotation speed pulse signal equal to the ratio between the number of rotor poles and the number of stator slots is 8:12 is output. The selection of whether or not the frequency conversion is performed by the rotation speed pulse signal frequency conversion circuit so that the number of pulses per rotation of the motor becomes equal .
[0014]
Further, when the number of poles of the rotor is 8, one rotation per n / 2 pulse or 3n / 2 pulse is obtained when the number of poles of the rotor is 10, one rotation per (n-2) / 2 pulse or 3 (N-2) / 2 A rotation speed pulse signal including a rotation speed pulse signal frequency conversion circuit for selecting whether to perform frequency conversion by the rotation speed pulse signal frequency conversion circuit so as to obtain a pulse is output. It is a thing.
[0015]
The energization width of the drive circuit is set to 135 to 180 degrees in electrical angle.
[0016]
The drive circuit is a sine wave drive circuit.
[0017]
Further, the energization width of the drive circuit is set to 150 ° in electrical angle.
[0018]
Further, the energization width of the drive circuit is set to 150 ° in electrical angle, the applied voltage during the first energization period is set to the first value, and the applied voltage during the second energization period is set to the second value. It is.
[0019]
Further, the ratio of the first value and the second value is sin (π / 3): 1 (approximately 0.866: 1).
[0020]
Further, 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 incorporated in the motor.
[0021]
The rotor has an IPM structure with a built-in magnet.
[0022]
Moreover, it is set as the electric equipment carrying these brushless motors.
[0023]
Moreover, it is set as the motor vehicle carrying these brushless motors.
[0024]
As described above, according to the present invention, it is possible to easily replace a brushless motor that realizes low noise and low vibration from a conventional product without changing a rotation speed detection circuit in a device on which the brushless motor is mounted.
[0025]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0026]
(Example 1)
FIG. 1 shows a rotor 11 having 10 poles, a stator 13 having windings 12 a in 12 slots 12, a three-phase connected stator 13, a drive circuit 14 for conducting three-phase full-wave current to the stator 13, Position detection elements 15a to 15c for detecting positions, a position detection signal processing circuit 16 for processing output signals 15ao to 15co of the position detection elements 15a to 15c, and a rotation speed pulse signal 16ao generated by the position detection signal processing circuit 16 , A rotation speed pulse signal frequency conversion circuit 17 for converting the frequency of 16bo, and a rotation speed pulse signal output circuit 18 for outputting the rotation speed pulse signals 17ao and 17bo frequency-converted by the rotation speed pulse signal frequency conversion circuit 17 to the outside. The schematic structure of the brushless motor which becomes is shown.
[0027]
As shown in FIG. 2, the output signals 15ao to 15co of the position detection elements 15a to 15c are signals of 5 pulses per rotation, each having a phase shifted by an electrical angle of 120 °. The position detection signal processing circuit 16 processes the output signals 15ao to 15co to output a signal 15ao of 5 pulses per revolution or a signal 15bo of 15 pulses per revolution. This signal 15ao or signal 15bo is frequency-converted by the rotation speed pulse signal frequency conversion circuit 17, and a 4-pulse signal 17ao per rotation or a 12-pulse signal 17bo per rotation is output. This signal 17ao or signal 17bo is output to the outside through the rotation speed pulse signal output circuit 18. Needless to say, it is possible to freely select whether or not the frequency conversion is performed by the rotation speed pulse signal frequency conversion circuit 17. In the case of a conventional 4-pole rotor or 8-pole rotor, no conversion is performed.
[0028]
In this way, in a brushless motor in which the ratio of the number of rotor poles to the number of stator slots is 10:12, the induced voltage between lines can be made close to a sine wave, torque pulsation can be suppressed, and noise and vibration can be reduced. It can be.
[0029]
Also, by setting the drive circuit energization width to 135 to 180 degrees in electrical angle, there is a three-phase energization period at the time of phase switching, so the change in current flowing in the coil is reduced, torque pulsation is suppressed, and low noise・ 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 sinusoidal, and when the current flowing through each phase coil approaches a sine wave, the noise and vibration can be further reduced.
[0031]
In particular, the first energization period is set to an electrical angle of 30 °, which is generated at intervals of 30 °, and the ratio between the first value and 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, thereby further reducing noise and vibration.
[0032]
Furthermore, if this drive circuit is a sine wave drive circuit, the current flowing through the coil is 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 in the first embodiment is a sine wave drive circuit.
[0034]
In FIG. 3, the 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. The signal output circuit 28 is built in the motor, and the motor and the circuit can be integrated to reduce the size.
[0035]
Further, if the magnet 21a is a 10-pole rotor having an IPM rotor structure in which the rotor core 21b is built, high efficiency can be realized in addition to low noise and low vibration.
[0036]
(Example 3)
Example 3 is an example in which the brushless motor of the present invention is mounted in a room air conditioner indoor unit or 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. These brushless fan motors are driven to rotate during operation of the room air conditioner.
[0038]
Thus, by using this invention for the fan motor of a room air conditioner, there exists an effect | action which suppresses the resonance of the fan and apparatus main body at the time of a room air conditioner driving | operation, and low noise and low vibration are realizable.
[0039]
Example 4
In Example 4, the brushless motor of the present invention is mounted on a water heater, and is mounted on a blower fan motor for supplying air necessary for combustion.
[0040]
In FIG. 5, a sirocco fan 52 is attached to a blower fan motor 51, housed in a casing 53, and blown from an exhaust port 54 to a combustion pot 55 of a water heater main body 56. It has the effect of suppressing the resonance of the fan and equipment body during water heater operation, and can realize low noise and vibration.
[0041]
(Example 5)
In Example 5, 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 blowing 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 body during the operation of the air purifier, and can realize low noise and low vibration.
[0043]
The present invention is not limited to the above-described embodiments, and other uses include, for example, a fan motor of an air conditioner for automobiles that requires a quiet interior 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 apparent from the above embodiment, according to the first aspect of the present invention, even if the number of rotor poles is 10, a rotational speed pulse signal having the same number of pulses as that of a motor having a rotor pole number of 8 is output. It is possible to provide a brushless motor that can be easily replaced without changing the rotation speed detection circuit in the device on which the motor is mounted, and realizes low noise and low vibration.
[0045]
Further, as in the invention according to claim 2, the ratio of the number of rotor poles to the number of stator slots is set to 10:12 so that the ratio of the number of rotor poles to the number of stator slots is set to 2: 3. Also, the line-to-line induced voltage can be made close to a sine wave, torque pulsation can be suppressed, and noise and vibration can be reduced.
[0046]
In addition, since the energization width of the drive circuit is set to an electrical angle of 135 to 180 degrees as in the invention described in claim 4, there is a three-phase energization period at the time of phase switching, so that the change in the current flowing through the coil is reduced. Torque pulsation can be suppressed, and noise and vibration can be reduced.
[0047]
Further, by making the drive circuit a sine wave drive circuit as in the invention described in claim 5, the current flowing in the coil can be made close to a sine wave, and the ratio of the number of rotor poles to the number of status lots is 10: Since the line induced voltage can be made closer to a sine wave by setting it to 12, torque pulsation can be further suppressed, and noise and vibration can be reduced.
[0048]
In addition, by setting the current-carrying width of the drive circuit to 150 ° in terms of electrical angle as in the invention described in claim 6, the line-to-line induced voltage can be easily approximated to a sine wave, and the current flowing through the winding can be reduced. Since it can approach a sine wave, low noise and low vibration can be easily achieved.
[0049]
Further, as in the invention described in 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 energizing period is set to the first value, and the applied voltage in the second energizing period. By setting the magnitude to the second value, the current flowing through the winding can be made closer to a sine wave, and noise and vibration can be further reduced.
[0050]
Further, as in the invention according to claim 8, by setting the ratio of the first value and the second value to sin (π / 3): 1 (approximately 0.866: 1), in 150 ° energization The brushless motor with the lowest noise and vibration can be obtained.
[0051]
Further, by using an IPM structure with a built-in magnet as in the invention described in claim 10 and increasing the amount of magnetic flux of the magnet, high efficiency can be achieved in addition to low noise and low vibration.
[0052]
Further, as in the inventions of the eleventh and twelfth aspects, the resonance of the electric device main body or the automobile main body can be suppressed, and the device main body can be reduced in noise and 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 on which the brushless motor is mounted. 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 generation of a rotational speed pulse signal according to the first embodiment of the present invention. Cross-sectional view of the structure [FIG. 4] An explanatory diagram of application to a room air conditioner indoor unit / outdoor unit in Embodiment 3 of the present invention [FIG. 5] (a) An explanatory diagram of a fan motor for blowing in Embodiment 4 of the present invention (b) FIG. 6 (a) Application explanatory diagram to an air purifier in Example 5 of the present invention (b) Air cleaner in Example 5 of the present invention External view [Fig. 7] Schematic configuration diagram of a conventional brushless motor [Fig. 8] Explanatory diagram of rotation speed pulse signal generation of a conventional brushless motor [Explanation of symbols]
11, 21 Rotor 12 Slot 12a Winding 13 Stator 14 Drive circuit 15, 25 Position detection element 16, 26 Position detection signal processing circuit 17, 27 Speed pulse signal frequency conversion circuit 18, 28 Speed 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 three-phase connected to the slots, a drive circuit for conducting three-phase full-wave current to the stator, and 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, a rotation speed pulse signal frequency conversion circuit for converting a frequency of a rotation speed pulse signal generated by the position detection signal processing circuit, and the rotation speed pulse In a brushless motor comprising a rotation speed pulse signal output circuit that outputs a rotation speed pulse signal frequency-converted by a signal frequency conversion circuit,
Even if the number of slots is the same and the number of rotor poles is different, the number of revolutions is selected by the revolution number pulse signal frequency conversion circuit so that the number of pulses per revolution of the motor becomes equal. A brushless motor characterized by outputting a pulse signal. Motor so that the ratio of the number of poles of the rotor and the stator number of slots also I 10:12 der, poles and slots the ratio of the number of stator rotor and outputs a rotational speed pulse signal is equal to the case 8:12 2. The brushless motor according to claim 1 , wherein selection is made as to whether or not the frequency conversion is performed by the rotation speed pulse signal frequency conversion circuit so that the number of pulses per rotation is equal . When the rotor speed of the poles of 8 per revolution n / 2 pulse or 3n / 2 pulse is obtained when the number of poles of the rotor is 10, one rotation per (n-2) / 2 pulse or 3 (n -2) A brushless motor according to claim 1 or 2 , further comprising a rotation speed pulse signal frequency conversion circuit for selecting whether or not to perform frequency conversion by the rotation speed pulse signal frequency conversion circuit so as to obtain a / 2 pulse. .   3. The brushless motor according to claim 1, wherein the energization width of the drive circuit is set to 135 to 180 degrees in terms of 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 an energization width of the drive circuit is set to 150 ° in electrical angle.   The duration of energization of the drive circuit is set to 150 ° in electrical angle, and among the phase coils, two phase coils 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 first energization). The magnitude of the applied voltage in the period) is the first value, one phase is paused outside the first energization period, and the remaining one phase is in a voltage application state in opposite directions (hereinafter referred to as second energization). 3. The brushless motor according to claim 1, wherein the magnitude of the applied voltage during the period is set to the second value.   8. The brushless motor according to claim 7, wherein a ratio between the first value and the second value is set to sin ([pi] / 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 incorporated in the motor. The brushless motor of any one of Claims.   The brushless motor according to any one of claims 1 to 9, wherein the rotor has an IPM structure with a built-in magnet.   An electric device equipped with the brushless motor according to any one of claims 1 to 10.   The motor vehicle carrying the brushless motor of any one of Claims 1-10.

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