JPS58131571A - Detection of speed of hall motor - Google Patents

Abstract

PURPOSE:To detect the speed of a motor highly accurately by detecting the time required for the displacement of a specific position of a rotor magnet between two Hall elements. CONSTITUTION:When current is supplied to driving coils 3a-3d, a six-pole magnetized rotor magnet 1 is rotated. Consequently voltage with the phase difference of 90 deg. electric angle is taken out by a Hall element 41 opposed to the center of the N pole of the magnet 1 at the interval of 90 deg. electric angle and a Hall element 42 opposed to the part between the N and S poles. Since ''0'' intersecting point of the waveform of the voltage corresponds to the time a specific position B between the S and N poles of the magnet 1 passed through the elements 41, 42, the motor speed is detected from the time difference of said passing time. Said magnetized status makes it possible to omit a frequency generator or the like of which accuracy is sharply changed and the speed of the Hall motor can be detected highly accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting the speed of a Hall motor, and the magnetization accuracy of the rotor magnet can be improved by detecting the time required for the determination position of the rotor magnet to be displaced between two Hall elements. It is an object of the present invention to provide a method for detecting the speed of a Hall motor that can quickly detect the speed with high accuracy regardless of the speed.

Conventional Hall motor rotational speed control devices are equipped with a frequency generator consisting of a multi-pole magnet that rotates together with the rotating shaft and a coil that faces the magnet. The speed was controlled by detecting the frequency of the AC voltage waveform.

However, in the conventional Hall motor, the speed detection accuracy is affected by the magnetization accuracy of the frequency generator magnet, the flatness of the magnet surface and the coil, and the misalignment of the rotation axis between the magnet and the rotor of the motor body. There was a drawback that the speed could not be accurately detected.

Further, since a frequency generator is provided, it is difficult to downsize the device, and it also cannot be constructed at low cost.

The present invention eliminates the above-mentioned drawbacks, and an embodiment thereof will be described below with reference to the drawings.

FIG. 1 is a circuit diagram for explaining an embodiment of the Hall motor speed detection method according to the present invention, and FIG. 2 is a developed diagram of a six-pole magnetized two-phase Hall motor used in the method of the present invention. In the figures, the same components are given the same numbers. In Figure 2, a 6-pole magnetized rotor magnet (hereinafter referred to as rotor)
Between the stator coil 3a and the stator yoke 2 is the stator coil 3a.
~3d and Hall elements 4 arranged at an electrical angle of 90° apart.
1° 42, respectively, and the strength of the magnetic field between the rotor 1 and the yoke 2 is as shown in FIG.

Now, connect the motor drive circuit 7 to the terminal 5a so that the current stagnates in the coils 3a to 3d in the direction shown in FIG.

When a tortoise force is applied between terminals 5b and between terminals 5c and 5d, rotor 1 is rotated in the direction of arrow A from the position shown in the figure. This causes the output terminal 61a of the Hall element 41 to face the center of the north pole of the rotor 1.

63. From the voltage e shown in FIG. 2. Output terminal 62 of Hall element 42 facing between N and S poles of rotor 1
8.'Round pressure e shown in Figure 4 from 62b). , are extracted with a phase difference of 90 electrical degrees. In this waveform, the zero-crossing point at the rising edge indicates the time when the determination position between the S and N poles of the rotor 1 (for example, point B in FIG. 2) passes through the Hall elements 41, 4□.

Hall output voltage e. 1 t eQ2 are the comparators 8, , 8 . Here, the voltages are compared to produce the rectangular wave pulse signals a and b shown in Fig. 4, Fig. 5, Fig. 5, which have rising and falling points at the zero cross point shown in Fig. 5 (B), The signal is supplied to the motor drive circuit 7 and used as a coil drive signal. Note that the signal waveforms shown in FIG. 5 (5) to (2) are waveforms in a state where the rotational speed of the motor increases and returns to the original state again. On the other hand, pulse signals a and b are connected to capacitor C1 and resistor R1.
, a differentiating circuit 91 consisting of a diode D1. Capacitor C
8. Differential circuit consisting of resistor R1 and diode D29. The pulses C and d are respectively supplied to and differentiated into differentiated pulses C and d as shown in FIG. 5 (01, G). Pulse C is resistor R8
Transistor Tr is supplied with current from transistor Tr, which is turned on. Charging of capacitor C1 by the current of this instantaneous stabilized power supply E is completed and its collector potential becomes zero. During the off period of transistor Tr, transistor Tr is turned on. C
3 is discharged through the resistor R6, and its collector potential is increased with a time constant of R and O, as shown in FIG. 5(G).

During the rise of the signal e, a pulse d is supplied via the resistor R4 to the transistor Tr, which charges the capacitor C4 to turn it on.

The collector potential when on is approximately equal to the voltage e.

Since the buffer amplifier 10 has a high input impedance, the collector potential of the transistor Tr2 is held during the off period of the transistor Tr, and as a result, the voltage f as shown in FIG. 5(G) is taken out from the output terminal 11. Hall output voltage e as above. Since the zero cross point of 1°eo2 indicates the time when a certain point of the rotor 1 passes the Hall element 41.4□, the voltage e. The pulses c and d obtained by shaping the waveform of 11 eQ2 correspond to that time, and therefore the potential f obtained by sampling the voltage e with the pulse d is proportional to the rotational speed of this motor.

That is, point B in FIG. 2 is the Hall element 4. Let t (seconds) be the time required to move the cloth from directly above the Hall element 4□, and the transistor T immediately after reaching directly above the Hall element 42
If the collector potential of r2 is f (V), it is expressed as f=gexp (-one town). The voltage f proportional to time, that is, the rotational speed of the motor, is compared with a reference voltage in a comparator (not shown) to form a rotational speed error signal (i.e., time t is detected), and is supplied to the motor drive circuit 7 to drive the rotor 1. Control the speed so that it rotates at a constant speed.

As described above, the Hall motor speed detection method of the present invention detects the speed by detecting the time required for the determination position of the rotor magnet magnetic pole to displace from one of the two Hall elements to the other. The detection accuracy is independent of the magnetization accuracy of the rotor magnet magnetic poles, and it can be detected with higher accuracy than the conventional method of detecting speed by detecting the frequency of the signal from a frequency generator, and also uses a frequency generator. Since this is not necessary, the device can be made compact and inexpensive.

[BRIEF DESCRIPTION OF THE DRAWINGS] Figure 1 is a circuit diagram for explaining an embodiment of the method of the present invention, and Figures 2 and 3 are developed diagrams of a Hall motor used in the method of the present invention and illustrate magnetic field strength, respectively. Figures 4 (5) and (B) and Figures 4 to 5 (0 are signal waveforms for explaining the operation of the circuit shown in Figure 1. 1... Rotor magnet, 4.4.・Hall 1
2 Element, 7... Motor drive circuit, 8.8... Comparator 2, 9□, 9□... Differential circuit, 11... Output terminal, Trl, Tr, e** Transistor, 09
．． 04@... Capacitor, Bird... Resistor. 397- Procedural amendment February 16, 1980 Haruki Shimada, Commissioner of the Patent Office (Examiner of the Patent Office) 1. Case description 1982 Patent Application No. 4336 2. Name of the invention: Hall motor speed detection method 3. Patent of the person making the amendment Applicant address: 6221 3-12 Moriya-cho, Kanayō-ku, Yokohama-shi, Kanagawa Prefecture Name (432) Victor Japan Co., Ltd. Representative Director and President Michi Shishi - Department 4, Agent 5, Amendment order Date voluntary amendment 6, drawings subject to amendment. Contents of Z correction Among the drawings, Figure 2 will be corrected as shown in the attached corrected drawing. Figure 2 O-ri ob*h Procedural amendment February 7, 1980 Kazuo Wakasugi, Commissioner of the Patent Office (Examiner of the Patent Office) 1. Indication of the case 1982 Patent Application No. 4663 2. Name of the invention Hall motor speed detection method 3, person's patent for correction Applicant address 8221 3-12 Moriya-cho, Kanayō-ku, Yokohama, Kanagawa Prefecture Name (432) Victor Japan Co., Ltd. Representative Director and President Michi Shishi - Department unrepresented Detailed description of the invention and drawings in the subject specification of Supplement II, Voluntary Amendment No. 5, Date of Amendment Order. Contents of Supplementary Part II (1) In the specification, it is 1 stated in the 3rd line of the 4th line. . I is taken as [, and [-1-Y1 continues to rotate in the same direction (]
The direction of the current flowing through the 7th coil 3a, 3b and the τ1 coil 3c, 3d is changed so that The above configuration is similar to the conventional small
It is similar to the motor. Complement it with 1. and correct it. (3) Same, from the top line of page 5 to page 6, 11-i fl.
E. Since C3 and Rs are each constant values, the rotation speed in a proportional relationship with the time t and its reciprocal (the proportionality constant is determined by the number of poles of the rotor 1) is detected by the formula F. Output terminal 11 is a comparator amplifier (not shown)
1 and supplementary cover. (4) Same, page 6, lines 2-3, [rotational speed error...detected], J is [(i.e., time t detected) is taken as a rotational speed error signal, ” he corrected. ■ Among the drawings, Figure 1 has been corrected as shown in the attached revised drawing. Procedural Amendment (Patent Office Examiner) 1, Indication of Case, 1982 Patent Application No. 4 Roro 6, 2, Title of Invention: Hall Motor Speed Detection Method 3, Patent of Person Making Amendment Applicant Address 221 Shinsai'l11'7 Kanagawa, Yokohama r=:=1'Yamachi 3-chome m2 name (432) Representative of Victor Japan Co., Ltd.) Head - Section 4, Agent 5, Amendment order - Detailed description of the invention in the specification attached to appendix No. 11. Contents of Z correction

Claims (1)

[Claims] To detect the rotational speed of the rotor by detecting the time required for the judgment position of the magnetic pole in the rotor magnet to be displaced from one Hall element to the other Hall element of two Hall elements provided at a predetermined distance apart. A method for detecting the speed of a Hall motor using the following characteristics.