JPH0158750B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a three-phase commutatorless motor using essentially two position sensing elements.

Conventionally, in a commutatorless motor with a three-phase excitation winding, three position detection elements are arranged at intervals of 2π/3 in electrical angle to ensure stable and efficient driving. A method is adopted in which the corresponding three-phase position signals are detected and current is sequentially passed through the three-phase excitation windings with a width of approximately 2π/3 in electrical angle.
However, in the three-phase commutatorless motor mentioned above,
Since three position detection elements are required, the cost increases, and the three position detection elements must be arranged at a certain angle and mechanically precisely, which is especially important for small electric motors. This has the problem of increasing manufacturing costs.

The present invention provides a commutatorless motor that uses two position detection elements and logically processes the position signals detected by the elements to sequentially excite three-phase excitation windings stably and efficiently. In particular, the number of detecting elements is reduced by one compared to the conventional example, reducing cost, and two position detecting elements can be arranged, for example, in the same radial direction. This reduces the mounting error of individual position detection elements, making it possible to improve the performance and downsize the commutatorless motor.

Hereinafter, the present invention will be explained based on illustrated embodiments. FIG. 1 is a block diagram of the main parts of a three-phase commutatorless motor according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a position detection rotating body made of a ferromagnetic material, which rotates together with a rotating shaft 9, and a first position detection track 2 and a second position detection track 3 are formed concentrically. has been done. The first position detecting track 2 and the second position detecting track 3 are each magnetized with N and S poles encoded, respectively. 4
is a first position detection element consisting of a magnetically sensitive element using the Hall effect, which is arranged on a suitable fixed part so as to detect the encoded magnetic pole of the first position detection track 2. There is. Reference numeral 5 denotes a second position detecting element made of a magnetically sensitive element utilizing the Hall effect for detecting the coded magnetic pole of the second position detecting track 3, and this is also disposed on a suitable fixed part. ing. 7 has an outer peripheral surface of 4
The rotor is made of a pole-magnetized cylindrical permanent magnet and rotates together with the rotating shaft 9. 8 is a stator with three-phase excitation windings Ma, Mb, and Mc;
This may include the stator core. The position detection rotating body 1, the first position detection element 4, and the second position detection element 5 constitute a position detection means 10.

FIG. 2 is a detailed diagram of the position detection means in FIG. 1. In FIG. 2, the same components as those explained in FIG. 1 are given the same reference numerals. In FIG. 2, the first position detection track 2
is magnetized with four poles, and the magnetization angle between the N pole and the S pole during one electrical cycle is 1:2. The first position detecting element 4 and the second position detecting element 5 having input terminals A and B and output terminals D and C, respectively, are arranged with an angular difference of θ ₁ as shown. Here, the illustrated position A is referred to as the reference position of the first position detection track 2;
Let the phase with respect to the first position detection element 4 in the counterclockwise direction be θ _n . The second position detection track 3 also
Like position detection track 2, it is magnetized with four poles, and the relative magnetization positions with respect to the magnetized poles of the first position detection track are at positions where θ _n is approximately π/3 and 4π/3, and at the second position. The detection state of the magnetic pole of the detection element 5 changes from N pole to S.
At the poles, also θ _n is 2π/3<θ _n <π and 5π/3<θ _n <2
It is magnetized to change from S pole to N pole between π.

FIG. 3 is a circuit block diagram for generating three-phase position signals according to this embodiment, and FIG. 4 is a waveform diagram of the main parts in FIG. 3.

In FIG. 3, E is a DC power source whose one end is grounded. One end of the input terminal of the first and second position detection elements 4 and 5 is each grounded, and the other input terminal A is connected to one end of the DC power supply E on the non-grounded side. 11 is a logical processing means;
Differential amplifiers 12, 13 and waveform shapers 14, 15
, inverter circuit 16, and NOR gate circuit 1
7 and 18. Two outputs with a phase difference of 180 degrees from the first position detection element 4 are respectively inputted to the differential amplifier 12, and the outputs are waveform-shaped by the waveform shaper 14, as shown in FIG. 4a. In addition, the first position detector 4 outputs a signal a which is at a high level during a period when the north pole is being detected, and which is at a low level during a period when the first position detector 4 is detecting the south pole. Further, two outputs with a phase difference of 180° from the second position detection element 5 are input to the differential amplifier 13, and the output is input to the waveform shaper 15 and the fourth output is input to the differential amplifier 13.
As shown in FIG. b, the second position detection element outputs a signal b that is at a high level during the period when it is detecting the north pole, and is at a low level during the period when it is detecting the south pole.

In other words, the output a of the waveform shaper 14 outputs a low level when O≦θ _n <2π/3, π≦θ _n ≦ 5π/3, and 2π/3≦θ during one rotation of the position detection rotating body 1. _n ≦π, 5π
Outputs high level when /3≦θ _n ≦2π. In addition, the waveform shaper 15 operates during one rotation of the position detection rotating body 1, so that O≦
θ _n ≦π/3, θ ₁ ≦θ _n ≦4π/3 (however, 2π/3<
A high level is output during the period when θ ₁ <π) and θ ₂ ≦θ≦2π, and a low level is output during the period when π/3≦θ _n ≦θ ₁ and 4π/3≦θ _n ≦θ ₂ . Then, the signals a and b are sent to the NOR gate circuit 1.
8, the signal d shown in FIG. 4 d is input to the NOR gate circuit 17, and the signal b inverted through the inverter circuit 16 and the signal a are input to the NOR gate circuit 17, and the signal c shown in FIG. 4 c is input as the output. obtain.

In the manner described above, three-phase position signals a, c, and d, which correspond to the rotational phase of the rotor 7 and have a phase difference of 120 degrees in electrical angle, are obtained.

FIG. 5 is a block diagram of main parts of a second embodiment of the present invention, in which the same parts as in the first embodiment described above are given the same reference numerals. In the embodiment of FIG. 5, the first and second position detection tracks 2, 3
is provided on the non-magnetized portion of the permanent magnets that constitute the rotor 7, and in this case as well, the N and S poles are coded and magnetized in the ratio explained in the first embodiment. It is magnetized. Further, the first and second position detection elements 4 and 5 are arranged in the same radial direction and are fixed to the carrier plate 19.

In this embodiment as well, the magnetic pole position between the first and second position detection tracks 2 and 3 is corrected so that three-phase position signals a, c, and d as explained in the first embodiment can be obtained. magnetized. Furthermore, the method for obtaining three-phase position signals from the outputs of the first and second position detection elements 4 and 5 is the same as in the first embodiment described above.

In each of the above embodiments, the first and second position detection tracks were formed using two magnetic states, and a magnetically sensitive element was used as the position detection element.
It goes without saying that the present invention also includes the use of suitable well-known optical means.

As is clear from the above description, the present invention comprises three
Even in a phaseless commutator motor, only two position detection elements are required, making it possible to reduce the cost of the motor, and because it is possible to arrange two position detection elements in the same radial direction, the distance between the elements can be reduced. This is an excellent device that can reduce mounting errors, and can also be handled as one component by incorporating two position detection elements on the same semiconductor substrate, which also makes it possible to improve component management. have an effect. Furthermore, by configuring the two position detection tracks in the non-magnetized portion of the rotating magnet of the electric motor, the above effects can be obtained without requiring any increase in the number of parts.

[Brief explanation of drawings]

Fig. 1 is a main part configuration diagram of an embodiment of the present invention, Fig. 2
The figure is a detailed view of the position detection means section in the same embodiment.
FIG. 3 is a circuit block diagram of the logic processing means section in the same embodiment, FIG. 4 is a signal waveform diagram of the main part in FIG. 3, and FIG. 5 is a configuration diagram of the main part of another embodiment of the present invention. . DESCRIPTION OF SYMBOLS 1...Position detection rotating body, 2...First position detection track, 3...Second position detection track, 4...
...First position detection element, 5...Second position detection element, Ma, Mb, Mc...3-phase excitation winding, 8...Stator, 7...Rotor, 9...Rotating shaft, 10 . . . position detection means, 11 . . . logical processing means, 19 . . . carrier plate.

Claims (1)

[Claims] 1. A rotor including a permanent magnet, a stator including a three-phase excitation winding, and a position signal that generates a three-phase position signal corresponding to the rotational position of the rotor. A commutatorless motor that includes a generator and generates rotational force by sequentially exciting the three-phase excitation windings according to the three-phase position signals, wherein the position signal generator is based on a physical a ring-shaped first position detection track in which two states A and B having different physical characteristics are sequentially coded at an angular ratio of approximately 1:2 corresponding to the number of poles of the permanent magnet; A position detection rotor, which is formed with a first position detection track and a ring-shaped second position detection track in which two states having different physical characteristics are sequentially coded at different positions, and rotates integrally with the rotor. a first position-sensing element for detecting a coded physical state of the first position-sensing track corresponding to a rotational position of the position-sensing rotary body; a first period in which the first position detecting element detects the physical state A; and a first period in which the first position detecting element detects the physical state A; a second period in which physical state B is detected and the second position detection element detects physical state A or B;
The first position sensing element detects physical state B, and the second position sensing element detects physical state B.
or a logic processing means that outputs a three-phase position signal representing the third period for detecting A;
The second position detecting track is such that the physical state detected by the second position detecting element changes an odd number of times within the interval in which the first position detecting element detects the physical state A, and the physical state A is detected by the first position detecting element. The two physical states are such that the physical state detected by the second position detecting element changes once at approximately the center angle between the rotation angles of the rotor at which the position detecting element detects the physical state B. A three-phase commutatorless motor characterized by being coded. 2 Physical state A is magnetic pole N (magnetic pole S), physical state B is magnetic pole S (magnetic pole N), and the position detecting body is such that the first and second position detecting tracks are on the same plane or the same cylindrical surface. Located concentrically, N and S
a permanent magnet coded by two magnetic poles, and the first and second position detection elements also include magnetic sensing elements using the Hall effect attached in the same radial direction. A three-phase commutatorless motor according to claim 1. 3. The three-phase commutatorless motor according to claim 2, wherein the first and second position detection elements are arranged on the same carrier plate.