JP4626095B2 - Magnetic pole detection device for synchronous motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic pole detection device for a synchronous motor using a permanent magnet used as an electric motor for an elevator hoisting machine, that is, a rotary encoder.
[0002]
[Prior art]
Recently, as shown in FIG. 2, a machine room-less elevator in which the synchronous motor 1 is installed in the hoistway and the elevator car 2 is raised and lowered has been put into practical use.
[0003]
This motor 1 is a synchronous motor 1 using a permanent magnet 4 as shown in FIG. 3, and in the case of a synchronous motor, it is necessary to detect the position of the magnetic pole, and therefore usually includes a detection device 5 for detecting it. For example, it is very common to attach a hollow rotary encoder or a shaft type rotary encoder to the rotating shaft of the electric motor.
[0004]
Such rotary encoders are classified into an increment type that generates a pulse signal proportional to the rotation angle when the rotation shaft is rotated by an external force, and an absolute type that outputs a rotation angle as a digital value. [0005]
In general, as shown in FIG. 4, the light receiving and emitting device 7 sandwiches a rotary slit plate 6 having a slit and outputs three types of electric signals as shown in FIG. 5, A phase, B phase, and Z phase. A signal is generated, and the magnetic pole position is specified by performing forward rotation, reverse rotation, or calibration of the electric motor. That is, the magnetic pole position is calculated by counting the A-phase signal or the B-phase signal and calibrating using the Z-phase signal.
[0006]
[Problems to be solved by the invention]
However, in this case, the magnetic pole position cannot be accurately specified unless the motor is rotated once. In addition, when the absolute type is used, a pulse train corresponding to the number of magnetic poles is required, and if the number of poles of the motor changes, another rotary encoder must be prepared.
[0007]
Eventually, if the position of the magnetic pole cannot be specified, the motor cannot generate a normal torque, and in the case of an elevator using a gearless hoisting machine, the car moves in the worst sheave one rotation.
[0008]
The present invention has been made in view of the above points, and an object of the present invention is to provide a magnetic pole detection device that can be used in common even with electric motors having different numbers of magnetic poles.
[0009]
[Means for Solving the Problems]
In the present invention, an incremental type rotary encoder having a rotary slit plate and a light emitter / receiver is attached to a rotating shaft of a permanent magnet electric motor, and a pulsed electric signal is output. and a second pulse train in which the first pulse train and the rotary shaft to repeat oN / OFF rotary shaft every half rotation repeats oN / OFF at every quarter turn, prior Symbol said first pulse train The distinction from the first event to the fourth event by the combination of High and Low of the second pulse train, and the first pulse train and the second pulse train captured while the rotary encoder is rotating 1/4 Based on the rise or fall, the absolute position of the magnetic pole of the motor having more than four magnetic poles is specified.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, a slit is inserted into a rotary slit plate of a rotary encoder so that an output signal state can be divided into several stages of events.
[0011]
【Example】
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a front view showing a rotary slit plate of a rotary encoder according to the present invention, and FIG. 6 is a diagram showing an output signal of the rotary encoder according to the present invention.
[0012]
In the figure, reference numeral 10 denotes a rotary slit plate of a rotary encoder according to the present invention, which is provided with a slit 11 and a slit 12, and outputs an appropriate Z-phase signal to be described later. Reference numerals 13 and 14 denote slits for outputting conventional A-phase and B-phase signals.
[0013]
In the case of such slits 11 and 12, when the number of magnetic poles is 12 poles, for example, a multiple of 4, the relationship between the developed magnetic poles and the output signals 11a and 12a is as shown in FIG. On the other hand, if the number of magnetic poles is, for example, 14 poles other than a multiple of 4, the relationship between the developed magnetic poles and the output signals 11a and 12a is as shown in FIG. Therefore, a 2-bit absolute signal is generated for each rotation of the rotary encoder.
[0014]
If such a slit is provided, the output signals 11a and 12a are changed from a first event (signal 11a: High, signal 12a: Low) to a fourth event (signal 11a: Low, each of which is a combination of High and Low). Signal 12a: Low), and if the rotary encoder rotates at least 1/4, the position of the rotor of the motor can be confirmed. As a result, the absolute position of the magnetic pole can be specified regardless of the number of magnetic poles. It becomes.
[0015]
This is clear from the following explanation.
That is, the magnetic pole position can be determined as follows according to the number of magnetic poles of the electric motor.
In either case, the position adjustment is performed in advance with the output signal 11a, 12a rising to the north pole.
1) When the number of magnetic poles is a multiple of 4 By capturing the rising and falling edges of the output signal 12a, as shown in FIG. 6A, when the rising edge is captured, the next is always the N pole, and when the falling edge is captured, the next Always has the S pole. Therefore, by capturing only the output signal 12a, the magnetic pole position can be discriminated if it makes a quarter turn at worst.
2) When the number of magnetic poles is other than a multiple of 4, the state of the output signals 11a and 12a shown in FIG.
▲ 1 ▼ Output signal 11a when rotating right ↑ ↓
Output signal 12a ↑ ↑
Next magnetic pole NS
▲ 2 ▼ Output signal 11a when turning left ↑ ↓
Output signal 12a ↓ ↓
Next magnetic pole NS
According to the above method, in either case 1) or 2), the magnetic pole position can be specified if the electric motor rotates about ¼ worst.
[0016]
Next, FIG. 7 is a front view of a rotary slit plate showing another embodiment of the present invention. In the figure, reference numerals 11 ′ and 12 ′ denote slits, and two semicircular slits are arranged 90 ° out of phase. As in the case of FIG. 1, such slits 11 ′ and 12 ′ can obtain pulse signals divided into four events and specify the positions of the magnetic poles.
[0017]
【The invention's effect】
As described above, according to the present invention, by devising how to generate the Z-phase output signal, the position of the magnetic pole can be identified quickly and reliably even with a single detection device regardless of the number of magnetic poles of the motor. Can be made.
[Brief description of the drawings]
FIG. 1 is a front view showing a rotary slit plate of a rotary encoder according to the present invention.
FIG. 2 is an overall view of a machine roomless elevator.
FIG. 3 is an overall view showing a permanent magnet type synchronous motor.
FIG. 4 is a perspective view showing the overall structure of a conventional rotary encoder.
5 is a diagram showing an output signal waveform of the rotary encoder of FIG. 4;
FIG. 6 is a diagram showing output signal waveforms of a rotary encoder according to the present invention.
FIG. 7 is a front view showing a rotary slit plate of another example of the rotary encoder according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Rotary slit plate 11, 11 ', 12, 12', 13, 14 of rotary encoder Slit 11a, 12a of rotary slit plate 10 Output signal of rotary encoder 10

Claims (6)

An incremental type rotary encoder having a rotary slit plate and a light emitter / receiver is attached to the rotary shaft of the permanent magnet type motor, and a pulse-like electric signal is output. / 2 first of said rotary shaft and the pulse train repetition of oN / OFF for each rotation and a second pulse train repeated oN / OFF for each quarter turn, prior Symbol said first pulse train second pulse train The distinction from the first event to the fourth event by the combination of High and Low, and the rise or fall of the first pulse train and the second pulse train that are captured while the rotary encoder is rotating 1/4 Based on the above, the absolute position of the magnetic pole of the motor having more than 4 magnetic poles is specified. The synchronous motor magnetic pole detection device according to claim 1, wherein the rotary slit plate is provided with a semi-circular first slit and a quarter-circular second slit. 2. The magnetic pole detection of a synchronous motor according to claim 1, wherein the first slit and the second slit are arranged on the rotary slit plate so that the semicircular slits have a phase difference of 90 °. apparatus. 4. The magnetic pole detection device for a synchronous motor according to claim 1, wherein the first and second pulse trains are pre-adjusted so as to have N poles at the rising edge. 5. . 5. The magnetic pole detection device for a synchronous motor according to claim 2, wherein a Z-phase signal is generated by the first and second slits. 6. The magnetic pole detection device for a synchronous motor according to claim 1, wherein the motor is an elevator hoist motor.

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