JPH0343858B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applied to a drive source for a small output load, such as an electric fan for cooling an electronic circuit.
This relates to a one-phase semiconductor motor.

[Conventional technology]

Conventional single-phase semiconductor motors can be roughly divided into the following three types:
It is a one-phase electric motor with two technologies.

Firstly, since the known one-phase electric motor cannot be started automatically, it is started by cogging torque.

The second technique is disclosed in US Pat. No. 3,299,335, which facilitates startup by providing a non-magnetic field section between the N and S magnetic poles of the magnet rotor.

The third technique is disclosed in US Pat. No. 4,211,963, in which a sub magnetic pole is added to the main magnetic pole of the magnet rotor, and has substantially the same effect as the second technique.

[Problems to be solved by the present invention]

The conventional one-phase semiconductor motor described above has three problems. First, 180 in electrical angle
During the initial and final stages of rotation, especially at the final stage, in addition to the back electromotive force being zero, the magnetic core is magnetically saturated, causing an excessive armature current to flow, resulting in joule loss that does not contribute to torque. becomes large, leading to a decrease in efficiency.

Secondly, in order to prevent this, there are techniques in the aforementioned US Patent Nos. 3,299,335 and 4,211,963.
This technique has the drawback that the entire magnetic field of the magnet rotor cannot be effectively utilized for torque, resulting in a decrease in efficiency. In a coreless electric motor, the above-described phenomenon of magnetic saturation of the magnetic core does not occur, so the decrease in efficiency is small, but there is still a decrease.

Third, a Zener diode is connected in parallel to the armature coil to release the stored magnetic energy when the armature coil is de-energized. The breakdown voltage of this Zener diode must exceed the power supply voltage. Therefore, most of the magnetic energy is consumed inside the Zener diode, which has the drawback of being an ineffective power loss without contributing to the output torque. In the case of this type of three-phase electric motor, since diodes can be used, there is only a small loss when the current is cut off, and most of the magnetic energy can be converted into output torque.

For the above-mentioned reasons, there is a problem in that the efficiency decreases and reaches a limit of about 35% in any of the first, second, and third cases.

[Means for solving problems]

The first means includes a magnetic rotor and a fixed armature, and includes self-starting means for stopping the magnetic rotor avoiding the dead center position when the armature coil attached to the fixed armature is not energized. In a one-phase semiconductor electric motor, N and S magnetic poles of equal width are alternately arranged along the circumferential surface of a magnet rotor, and the magnetic field is strongest in the center of the magnetic poles and shifts to both ends. An even number of N, S magnetic poles are magnetized so that the strength gradually decreases as the magnetic field increases.
The first and second examples are the strength of the magnetic field of each magnetic pole.
One magnetoelectric transducer 8 that can obtain a position detection signal of
a, an electric circuit (block circuit A surrounded by a chain line) that maintains the reference voltage at zero voltage at startup and outputs and maintains the reference voltage that has increased to the set voltage after a set time; , first and second comparator circuits 38a and 39a, each of which has a second position detection signal as one input signal and the reference voltage described above as another common input signal; The detection signal and the reference voltage that has risen to the set voltage and is held are compared by the first and second comparator circuits, and only the section that exceeds the reference voltage is amplified and output from 120 degrees in electrical angle. 180 degree electrical angle amplified by the third and fourth position detection signals arranged as small-width rectangular wave electrical signals and the first and second comparison circuits when the reference voltage is zero voltage. a transistor 14a connected in series to the armature coils 5a, 5b, and a transistor 14b connected in series to the armature coils 5b, 5d;
At the same time, the third and third position detection signals are input to the base of the transistor 14a, conduction is made for the width of each position detection signal, and the fourth and fourth position detection signals are input to the base of the transistor 14b. An energization control circuit (block circuit C surrounded by a chain line C) that inputs a signal and controls the energization of the armature coil by making it conductive by the width of each position detection signal is connected in parallel to the armature coils 5a and 5c. The fourth position detection signal becomes the base input, and when the width of the position detection signal is made conductive and the armature coils 5a and 5c are disconnected, the stored magnetic energy is converted into a current and discharged. Transistor 14 to be extinguished
c is connected in parallel to the armature coils 5b, 5d, the third position detection signal becomes the base input, conduction is made by the width of the position detection signal, and the armature coils 5b, 5d are de-energized. and a transistor 14d that converts the stored magnetic energy into a current and causes the discharge to disappear.

The second means includes a magnetic rotor and a fixed armature, and includes a self-starting means for stopping the magnetic rotor avoiding the dead center position when the armature coil attached to the fixed armature is not energized. In a one-phase semiconductor electric motor, N and S magnetic poles of equal width are alternately arranged along the circumferential surface of a magnet rotor, and the magnetic field is strongest in the center of the magnetic poles and shifts to both ends. An even number of N, S magnetic poles are magnetized so that the strength gradually decreases as the magnetic field increases.
The first and second examples are the strength of the magnetic field of each magnetic pole.
One magnetoelectric transducer 8 that can obtain a position detection signal of
a, an electric circuit (block circuit A surrounded by a chain line) that maintains the reference voltage at zero voltage at startup and outputs and maintains the reference voltage that has increased to the set voltage after a set time; 1 and the second position detection signal each become one input signal,
The first and second comparison circuits 38a and 39a have the reference voltage as another common input signal, and the first and second position detection signals and the reference voltage that has risen to the set voltage and are held there. A third array of rectangular wave electrical signals having a width smaller than 120 degrees in electrical angle, in which only the section exceeding the reference voltage is amplified and output as compared by the first and second comparison circuits; A fourth position detection signal, and a third and a third array of rectangular wave electrical signals having a width of 180 electrical degrees amplified by the first and second comparator circuits when the reference voltage is zero voltage. Four transistors 47a, 4
A transistor bridge circuit (block circuit D surrounded by a chain line) consisting of 7b, 47c, and 47d,
The DC power supply that supplies power to the transistor bridge circuit and the base input control of the transistors 47a and 47c located on the diagonal lines of the transistor bridge circuit are controlled by third and third position detection signals, and each position detection signal is The armature coil B is energized in one direction by conducting only the width of An electric circuit that conducts only the width of the signal and energizes armature coil B in the opposite direction, and armature coil B
is connected in parallel to the fourth position detection signal as a base input, conducts by the width of the position detection signal, and converts the stored magnetic energy into a current when the armature coil B is de-energized. The transistor 48a that causes the discharge to disappear is connected in parallel with the armature coil B, and the third position detection signal becomes the base input, and when the current is turned on by the position detection signal and the armature coil is de-energized. Additionally, a transistor 48b converts the stored magnetic energy into a current and causes the discharge to disappear.

[Effect]

When the armature coil is initially energized, its inductance is 20 in the case of a motor with a magnetic core.
Since it is on the order of millihenries (for a motor with an output of 1 to 2 watts), the rise of the current is relatively slow and the back electromotive force is small, but the current value is small and the joule loss is small, so it has little effect on efficiency. This will lead to a decline.

However, at the end of energization, the core is almost saturated by the magnetic flux of the magnet rotor, and the inductance is reduced to only the coil, so the inductance decreases to about 5 millihenry. Therefore, at the end of energization when the field magnetic field is small or zero, a significantly large armature current flows, and since this does not contribute to torque, it becomes the main cause of deterioration of efficiency.

In order to eliminate this inconvenience, the position sensing element 1
Using a piece, cut off the initial and final stages of energization,
The efficiency is increased by 15 to 20% over known electric motors of this type, which is a function of the present invention. In the case of a coreless electric motor, the inductance is about 4 to 5 millihenry, so the cause of the decrease in efficiency is small, but the circumstances in which efficiency is increased by the above-mentioned means are exactly the same. Therefore, they have the same effect using the same means.

Furthermore, according to the above-mentioned means, it is difficult to start up using cogging torque, so a means is added to keep such means inactive at the time of start-up. Furthermore, a means has been added to convert the magnetic energy accumulated in the armature coil into output torque using a switching element such as a transistor, further increasing the efficiency (efficiency increases by 3 to 4%). be.

〔Example〕

Next, according to an embodiment of the device of the present invention shown in the drawings,
The details will be explained below. Components with the same symbols in the drawings are the same members, so a description thereof will be omitted.

FIG. 1 is a front view showing the overall structure of an electric motor with a magnetic core.

In FIG. 1, symbol 4 is a motor magnetic core made by laminating silicon steel plates. It has a 4-ball configuration, and the salient poles are shown as symbols 4a, 4b, 4c, and 4d, and their widths are slightly smaller than 90 degrees.
They are far apart.

Each salient pole has armature coils 5a, 5b, 5c,
5d is installed. The central part of the magnetic core 4 is a protruding hole into which a metal cylinder 2 is fitted, and the cylinder 2 fixes the magnetic core 4 to a main body (not shown) to form a fixed armature.

An outer ring of a ball bearing 3 is fitted inside the cylinder 2, and a rotating shaft 1 is rotatably supported on the inner ring.

A bottom center portion of a mild steel cup 13 pressed into a cup shape is fixed to one end of the rotating shaft 1.

An annular magnet rotor 6 is fixed inside the cup 13, and the magnet rotor 6 has a 90 mm
N and S magnetic poles with an opening angle of 100 degrees are arranged as shown in the diagram,
The magnetic poles rotate together with the rotating shaft 1, facing the salient poles 4a, 4b, . . . with gaps (about 0.5 mm) interposed therebetween.

A central ring of a magnetic core 7, which includes salient poles 7a, 7b, 7c, and 7d and is made into the shape shown in the figure by die-cutting a mild steel plate or a silicon steel plate, is fixed to the magnetic core 4 in an overlapping manner.

The width of the salient poles 7a, 7b, ... is the width of the magnetic poles 4a, 4.
The salient poles 4a, 4b, . . . are spaced apart from each other by approximately 1/2 of 90 degrees, and the salient poles 4a, 4b, . As shown in the figure, the base 7e of the salient pole 7b is set to be located midway between the armature coils 5b and 5c.

Therefore, since the base portion 7e is prevented from overlapping the armature coils 5b, 5c, there is an effect that the thickness (length in the direction perpendicular to the plane of the drawing) of the motor can be reduced. The above-mentioned situation is exactly the same for the bases of the other salient poles 7a, 7c, and 7d.

FIG. 2b is a 360 degree development view of the salient poles 4a, 4b, 4c, 4d and 7a, 7b, 7c, 7d. As will be described in detail later, reference numeral 8a denotes a Hall element, ie, a position detection element, which is fixed to the fixed armature 4 via a suitable support and faces the magnetic pole surface of the magnetic rotor 6.

Salient poles 4a, 4b, ... and salient poles 7a, 7b, ...
Although there is a gap 7f shown by an arrow between them, there is no problem even if they are arranged closely.

FIG. 2a shows the magnetic poles 6a of the magnet rotor 6,
6b,... is a 360 degree development view. Salient poles 4a, 4b, ... and salient poles 7a, 7b, indicated by dotted lines.
. . . and the Hall element 8a show a state in which the respective members and the magnet rotor 6 are opposed to each other.

The output of the Hall element 8a distinguishes whether it is under the N pole or the S pole, and when the armature coils 5a, 5c and the armature coils 5b, 5d are alternately energized, the well-known one-phase semiconductor It becomes an electric motor and is used in a wide range of applications as a drive source for small electric fans.

Cogging torque is generated in the magnetic rotor 6 due to the salient poles 7a, 7b, . The efficiency of the above-mentioned electric motor deteriorates due to the following reasons, and when the input power is about 1 to 2 watts, the efficiency is about 32% to 35%. 3
Compared to this type of phase, which has an efficiency of 60-70%, the efficiency is significantly degraded.

The device of the present invention eliminates the causes of such efficiency deterioration, increases efficiency by 20% to 25%, and increases efficiency by 55% to 55%.
The composition was set at around 60%. Next, the details will be explained.

Curves 22a, 22b, . . . in the graph of FIG.
is an output torque curve of a general one-phase electric motor. Curve 23 is the above-mentioned cogging torque curve, and the combined torque curve of both has no dead center and can be started automatically.

The armature current curves are curves 25a, 25b,...
It is shown as... This curve will be explained with reference to FIG.

FIG. 10 shows the magnetic poles 6a, 6b, 6d of a part of the magnet rotor 6 and the salient poles 4a facing thereto,
A developed view of the armature coil 5a is shown.

The drawing is shown when the salient pole 4a directly faces the magnetic pole 6a. Considering the case where the armature coil 5a is energized and excited to the N pole and the magnetic pole 6a rotates in the direction of arrow G, the magnetic flux due to the magnetic pole 6a is in the direction of arrow 32, and the direction of the magnetic flux due to armature coil 5a is as shown by the arrow. 32, and the magnetic flux in the direction of arrow 32 rapidly decreases as the current is applied, so a large back electromotive force is generated, and the armature current becomes the rising part of the left end of the curve 25a in FIG. 6, causing an excessive current. is suppressed. Therefore, although the field magnetic field in this part is zero or small and the output torque is also small, the joule loss is also small and does not have a large effect on the efficiency.

Next, while the magnet rotor 6 rotates 45 degrees in the direction of arrow G, the magnetic flux in the direction of arrow 32 due to the magnetic poles 6a decreases to zero. Also, during this time, armature coil 5
Since the magnetic flux in the direction opposite to the arrow 32 indicated by a is almost constant, the composite magnetic field gradually increases in the direction opposite to the arrow 32, and the counter electromotive force due to this also increases, and when rotated by 45 degrees, the counter electromotive force increases. . That is, the rate of change in the magnitude of the magnetic flux passing through the armature coil 5a with respect to time becomes large. Therefore, the armature current has a low value at the center of the motor 25a in FIG.

During the next 45 degree rotation, at the beginning, 6
d (S pole) causes the magnetic flux in the direction of the arrow 33 to flow into the salient pole 4a, and this direction coincides with the magnetic flux from the armature coil 5a, so the rate of change of the composite magnetic flux with respect to time is maximum, and therefore The back electromotive force also reaches its maximum value, the armature current also reaches its minimum value, and the efficiency also reaches its maximum value. This point is a point slightly to the left of the dotted line 27b in FIG.

When the magnet rotor 6 further rotates, the arrow 3
The magnetic flux due to the magnetic pole 6d indicated by 3 increases rapidly,
As the magnetic core approaches saturation, the induction constant rapidly approaches 1 and the inductance rapidly decreases. According to actual measurements, the inductance at the left end of curve 25a is 20
millimeters, and at the right end it is about 5 millimeters.
However, this applies to a motor with an input of about 1 to 2 watts. Therefore, the back electromotive force also decreases rapidly and the armature current increases rapidly. Furthermore, since the magnetic energy, which is proportional to the inductance, also decreases rapidly, the released magnetic energy results in an increase in the armature current. Therefore, as shown in the rightmost curve of curve 25a in FIG. 6, when the armature current increases rapidly and rotates 90 degrees, the armature current is cut off, but according to actual measurements, the peak value at this time is: The value is almost the same as the starting current.

In this vicinity, the field magnetic field is small or zero, so there is almost no output torque and the ineffective Joule loss increases rapidly.

The situation is exactly the same for the other magnetic poles 4b, 4c, and 4d.

As the magnet rotor 6 rotates, the ninth
The armature currents are curved as shown in the motors 25a, 25b, . . . in the figure.

Assuming that the armature rotates at 3000 revolutions per minute, 4
Since 12,000 electric motors 25a, 25b, . . . are obtained, energization shown by the curves 25a, 25b, . Expressed in extreme terms, this fact results in a DC armature that is activated 12,000 times per minute, which should be understood to be the main cause of deterioration in efficiency.

To eliminate the above-mentioned drawbacks, follow the dotted line 2 in Figure 9.
The optimum means is to stop the armature current at the point indicated by 7b. That is, it is preferable to cut off the current at the point indicated by the dotted line 27b. Furthermore, for the reason described later with reference to FIG. 8a, the current supply is cut off at the dotted line 27a even in the initial stage of the current supply. Since the torque to the left of the dotted line 27a is small, its influence on efficiency is small.

As described above, since the current is cut off at the beginning and end of the current, there is no counter torque mixed in even if the position of the Hall element 8a is slightly shifted, and there is an advantage that manufacturing is easy.

Therefore, the energization curves are curves 26a, 26b,...
…become that way.

The above-mentioned situation is exactly the same even when the number of magnetic poles of the magnet rotor 6 and the corresponding number of salient poles are increased.

Figure 8a shows a control circuit to eliminate the above problems.
This will be explained next.

In FIG. 8a, the output of the Hall element 8a (indicated by the same symbol in FIG. 2), which is energized by the DC power supply positive electrode 10a, is amplified by the operational amplifier 38b, and the output waveform at point E is as shown in FIG. It is shown by curves 15a, 15b, . . . in the graph.

Since the Hall element 8a faces the magnetic poles 6a, 6b, . . . as shown in FIG. 2, its output can be obtained. The output of the transistor 37a, that is, F
The outputs of the points are as shown in 20 and 20a in FIG. In order to obtain such an asymmetrical output, it is necessary to magnetize the magnetic poles 6a, 6b, . . . as shown in FIG. That is, the boundaries of each magnetic pole are
The magnet is penetrated by the width indicated by the arrow 21 between the dotted lines and magnetized.

The Hall element 8a is fixed to the center of a rectangular piece of mild steel indicated by symbol 8. The soft steel piece 8 is connected to the magnetic pole 6a,
6b, . Hall element 8a
The output of N rapidly rises to a peak value, and then when the mild steel billet 8 reaches the part indicated by the arrow 21, the output of N,
Since the south pole is short-circuited by the soft steel piece 8 and the magnetic field is closed, the magnetic flux passing through the Hall element 8a decreases. Therefore, the side of the curve 20 in FIG. 6 with the dotted line 27b is
It descends in a gentle curve as shown.

As described above, the output curve of the Hall element 8a is an asymmetric curve.

The magnetic poles 6a, 6b, . . . have conventional magnetization curves, and the side surfaces of the magnetic poles 6a, 6b, . The same purpose can be achieved by facing the sides. In this case, the magnetic poles 6a, 6b, .
... can be magnetized. operational amplifier 38a
serves as a comparison circuit.

Since the configuration is such that a reference voltage is applied to the terminal 40 at the same time as the positive voltage is applied to the terminal 10b, at this time, one terminal of the operational amplifier 38a becomes low due to the voltage drop across the resistor 41a. level, and the output at point H is the curve 15a, 1 in FIG.
5b, . . . have the same output. Therefore, the conduction of the transistor 14a is performed only in sections separated by the same angle in each section of 180 electrical degrees, and therefore, the armature coils 5a and 5c are energized in the direction of the arrow only in the conduction sections.

Operational amplifier 3 by inputting the + terminal and - terminal of the operational amplifier 39a by the transistor 37b
Due to exactly the same circumstances, the output at one point 9a produces a rectangular wave output every 180 degrees whose phase differs by 180 degrees (electrical angle) from the output at point H, and this output turns on the transistor 14b.

Therefore, armature coils 5a, 5c and 5b, 5
d is alternately energized and rotated as a one-phase motor.

After a predetermined time, the input to one terminal of the operational amplifiers 38a and 39a becomes a reference voltage due to the resistors 41a and 41c and the capacitor 41b, and this voltage becomes the value shown by the dotted line 16a in FIG.

The output of the H point of the operational amplifier 38a is indicated by the dotted line 27
The output of the section between a and 27b is the motor 18a, 18b, . . . in FIG. 6, and the output at point I of the operational amplifier 39a is the curve 19a, 19b, .
become that way.

The dotted lines 27a and 27b are the dotted lines 27a and 27b in FIG.
27b, so that the reference voltage 1
6a increases efficiency, as discussed above with respect to FIG.

The armature coils 5a, 5c and 5b, 5d may be connected in series or in parallel. Hall element 8a
is a magnetoelectric transducer, but any other position sensing element may be used as long as it achieves the same purpose.

As mentioned above, the salient poles 7a, 7b, . . . can be self-started by the jerking torque.

The cogging torque curve according to this example is the 9th
Since it is shown as symbol 23 in the figure, the salient pole 7
By increasing the thickness of a, 7b, . . . , the output torque can be increased. Therefore, there is an effect that the resultant torque of the curves 22a, 22b, . . . and the curve 23 can be made almost flat.

Also, since the width of the salient poles 4a, 4b, . . . is close to 90 degrees, the output torque is large, and the cogging torque caused by these poles is small, so starting is ensured and machine noise is reduced.

In order to obtain good efficiency, it is necessary to cut off the armature current at the point indicated by the dotted line 27b in FIG. According to this means, there is no output torque between the dotted lines 27 and 27b, so at the point of the dotted line 27b, there is no torque according to the cogging torque curve 23, and the engine cannot be started. Therefore, it is necessary to start by the above-mentioned means and cut off the current outside the dotted lines 27a and 27b after starting.

As can be seen from the above explanation, during startup, each armature coil is energized alternately through 180 electrical degrees, so the cogging torque described above allows accurate startup, and speed increases. Therefore, the initial stage of energization is delayed, the final stage is completed early,
The current flow is less than 180 degrees, and during rated operation,
The current is cut off outside the positions of dotted lines 27a and 27b in FIG.

Therefore, the efficiency is increased, and compared to known electric motors of this type, there is a feature that an additional efficiency of 15 to 20% can be obtained.

Incidentally, by adjusting the height of the dotted line 16a which is the reference voltage in FIG. 6, the position at the end of the energization described above can be changed, so that the point of maximum efficiency can be selected.

In this embodiment, the cogging torque is obtained by the salient poles 7a, 7b, . . . , but it can also be achieved by other known means.

Even if the curve 20 in FIG. 6 is symmetrical, the initial and final stages of energization will also be symmetrical. Therefore, the current-carrying section can be set to, for example, 120 electrical degrees. According to this means, the current is supplied in the same way as the coil in the one phase portion of a semiconductor motor with a three-phase Y-connection. Therefore, although the output torque is halved, the efficiency is the same, and it is possible to obtain an efficiency close to 60%.

Next, the circuit shown in FIG. 8b will be explained.

In FIG. 8b, symbol 43 is a monostable circuit. At the same time as a voltage is applied to the terminal 10b in FIG. 8a, an electric pulse is also input to the terminal 42,
The monostable circuit 43 starts to operate, and its output is passed through the inverting circuit 44, and the terminal 44a becomes a low level. Since the output of the terminal 44a is input to one terminal of the operational amplifiers 38a and 39a in FIG. 8a,
By its output, transistors 14a and 14b
conducts alternately every 180 electrical degrees to energize the armature coils 5a, 5c and 5b, 5d.

Therefore, capacitor 41b, resistors 41a, 41
It starts automatically in the same way as the time constant circuit using c.

After the set time, that is, when the output of the monostable circuit 43 disappears, the terminal 44a becomes the set voltage, that is, the voltage indicated by the dotted line 16a in FIG.
Since the initial and final stages of conduction of 4a and 14b are stopped, the same objective is achieved.

Illustrated in FIG. 8c is another means of achieving the same object as that described above.

In FIG. 8c, a voltage proportional to the rotational speed of the motor is input to the terminal 45. Such voltage can be obtained by known means.
At startup, the input to the terminal 45 is at ground level.

At this time, since the transistors 45 and 46 are non-conductive, the output of the terminal 46a becomes a low level, and this output becomes the operational amplifier 38a and 39a.
Since it is input to one terminal of , it can be started automatically as in the previous embodiment.

When the rotational speed of the motor increases, transistors 45 and 46 become conductive, so that the output at terminal 46a increases to the voltage at terminal 40. Since the voltage at the terminal 40 is the reference voltage, that is, the same voltage as the dotted line 16a in FIG. 6, the operational amplifier 38 in FIG. 8a
The output of a, 39a becomes smaller than 180 degrees in electrical angle, the same objective is achieved, and a highly efficient one-phase semiconductor motor can be obtained.

Next, referring to FIG. 8a, a means for effectively converting the magnetic energy stored in the armature coil into output torque will be described.

The outputs of the operational amplifiers 38b and 39b serve as base inputs of transistors 14d and 14c, respectively. Only when the outputs of the operational amplifiers 38b and 39b are at low level, the transistors 14a and 14
c is made conductive.

Therefore, when the operational amplifier 39b has a positive output, the transistor 14c becomes non-conductive, and at this time the armature coils 5b and 5d are energized. When the output of the operational amplifier 39b becomes low level, the transistor 14c is in a conductive state, but since the armature coils 5a and 5c are energized, there is no collector current of the transistor 14c. However, when the armature coils 5a, 5c are de-energized, the current flowing in the direction of the arrow due to the release of magnetic energy flows through the transistor 14c and becomes effective torque, so that the purpose is achieved.

Transistor 1 by the output of operational amplifier 38b
Since the effect of the base control of 4d is under exactly the same circumstances, its operation and effect are also the same.

As can be understood from the above explanation, when the armature current is cut off at the point indicated by the dotted line 27b in FIG.
Although large magnetic energy is stored in the armature coil, this magnetic energy is converted into positive torque, further increasing efficiency.

In this type of motor, a Zener diode is used to release the magnetic energy stored in the armature coil. Also, since this breakdown voltage needs to be higher than the power supply voltage, most of the magnetic energy is consumed inside the Zener diode, and the other part becomes a counter-torque. Compared to such measures, the measures of the invention have the special advantage of converting a large part of the magnetic energy stored in the armature coils into useful torque, as described above.

The present invention can also be applied to coreless armatures. Next, I will explain it. FIG. 3 shows an armature of an axial gap type coreless armature.

Returning to FIG. 3, a ball bearing 28a is press-fitted into the cylindrical support 15 set up on the main body (not shown), and a rotary shaft 28 is rotatably supported by the ball bearing 28a.

At the upper end of the rotating shaft 28, as shown in FIG. 4b,
The center of the mild steel disc 31 is fixed, and the mild steel disc 31
A disc-shaped magnet 30 is arranged so that it forms a magnetic path.
is fixed.

FIG. 4a is a front view of the magnet 30, with N,
The S magnetic poles are alternately magnetized at equal pitches of 90 degrees,
The magnetic poles are labeled 30a, 30b, 30c, 30d. The magnetic field of the magnet 30 penetrates the armature coils 11a, 11b, . In the case where the magnetic flux exceeds 100%, the magnetic path is closed using a molded magnetic powder made of plastic material or a sintered body of silicon steel powder to avoid eddy current loss. The magnetic disc 12 is provided with an insulating film such as a plastic material, and the armature coils 11a, 11b, . . . are fixed thereon with an adhesive. The armature coil described above is 1
This is the phase coil.

Printed wiring is provided on the plastic film described above, and each lead-out terminal is connected by the printed wiring so that the armature coils 11a, 11c and 11b, 11d are connected in series or in parallel, respectively. This printed wiring is omitted and not shown, but only lead-out terminals 12a, 12b, and 12c that supply power to each coil are shown.

In the case of high-speed rotation, eddy current loss occurs in the magnetic disc 20. Therefore, as shown by the dotted line K, a hole is provided in the center, or the magnetic disc 12 is
In some cases, a method is adopted in which the substrate is removed to form a plastic substrate, and printed wiring is performed on this to perform the required wiring. However, the output torque decreases. A Hall element 8a is fixed to the magnetic disk 12 at an intermediate portion between the armature coils 11b and 11c.

Mild steel plates 29a and 29b having the shape shown are fixed inside the armature coils 11a and 11c.
The mild steel plates 29a and 29b are the salient poles 7a and 7a of the previous embodiment.
7b, . . . (shown in the second diagram).

The output of the Hall element 8a causes the armature coil 1 to
The circuit for controlling the energization of 1a, 11b, . . . is exactly the same as that shown in FIG. 8a. The armature coils 5a, 5b, . . . in Fig. 8a are
By reading it as 1a, 11b, ..., 1
It can be operated as a phase semiconductor motor.
Next, the features of this embodiment will be explained with reference to FIGS. 5 and 11.

At the same time as a voltage is applied to the terminal 10b in FIG. 8a, a reference voltage is applied from the terminal 40. At this time, since one terminal of the operational amplifiers 38a and 29a is held at a low level, the output at point H is a rectangular wave with a width of 180 degrees (electrical angle).
is obtained each time a is below the north pole of the magnet rotor 30. Every time there is a Hall element 8a under the magnetic field at the S pole, a rectangular wave of the same width is output from the operational amplifier 39a.
It is obtained from point I of . Therefore, transistor 14
a and 14b are alternately conductive every time the magnet rotor 30 rotates 90 degrees, thereby alternately energizing the armature coils 11a and 11c and the armature coils 11b and 11d connected in series thereto.

Therefore, the soft steel pieces 29a and 29b shown in FIG. 3 self-start and rotate due to the effect of cogging torque.

After the set time, the capacitor 41b is charged, so one terminal of the operational amplifiers 38a and 39a becomes the reference voltage. This voltage is shown as a dotted line 16a in the graph of FIG.

Since the Hall output (output at point F) through the transistor 37a is shown as curves 16b and 16c in FIG. 5, only the output between the dotted lines 17c and 17d is the output of the operational amplifier 38a, and the output is the curve 18a in FIG. , 18b, .... Therefore, the energization width of the armature coils 11a and 11c is about 120 degrees (electrical angle). In order to increase the output torque of the field magnetic field, when the magnetic field has a shape close to a rectangular wave, the Hall element 8a is provided a little apart from the magnetic pole face, so that the Hall output is made as shown in curves 16b and 16c. be able to. For some reason, the output at point I via the transistor 37b and the operational amplifier 39a becomes curves 19a, 19b, . . . in FIG.
Its width is about 120 degrees (electrical angle), and the armature coils 11b and 11d are energized by the transistor 14b.

The curve of the output torque and the current flowing through the armature coil in the case of the above rotation is shown in the graph of FIG.

In Figure 11, curve 2 with the same symbol as in Figure 9
2a, 22b, ... and the curve 23 are the armature coils 11a, 11c and 11b, 11d, respectively.
The output torque and mild steel piece 29 obtained alternately by
This is the cogging torque due to a and 29b. These output torques are the output torques at the time of startup, but since there is no dead center, they start automatically.

The armature currents are shown as curves 35a, 35b, . There is a small peak value at the beginning of each curve, and a large peak value at the end. In the case of a coreless electric motor, the inductance of the armature coil is about 4 millihenry (when the input is about 1 to 2 watts), so the curves 25a, 25b, . . . in FIG.
Unlike ..., a peak value is added at the beginning.

After startup, curve 18 of the graph in FIG.
Since the current is energized by the width of a, the energization outside the dotted lines 34a and 34b is removed, and the output torque is equal to the curve 3.
It will look like 6a. This width is about 120 degrees.

The peak value portions of the current on the left and right sides of the curve 35a are:
The field magnetic field is small, the output torque is small, and the Joule loss is large, which causes efficiency to deteriorate. Since the current is energized at approximately 120 degrees (electrical angle), this cause is removed and efficiency is improved.

The situation is exactly the same for the other armature current curves 35b, 35c, . . . and 36b, 36c, . . . and the efficiency increases.

When energized at an electrical angle of about 120 degrees, the efficiency increases to exactly the same level as a three-phase semiconductor motor with a Y-type connection. However, the output torque will be 1/2.

In the case of a coreless electric motor, there are peak values at both ends of the curve 35a, so the efficiency is maximized by setting the initial and final energization sections equally at 30 electrical degrees. Armature coil 3c in Fig. 3,
The present invention can be implemented even if 3d is removed or the magnetic rotor has six magnetic poles. If both ends of the curves 25a, 25b, . At both ends of the torque curve 22a in FIG. 11, the magnetic field does not interlink the armature coil at right angles, so there is a drawback that a force is generated in a direction perpendicular to the plane of the paper of FIG. 3, inducing vibration. In this embodiment, since no current is applied to both ends, the above-mentioned vibrations are eliminated and the generation of mechanical noise, which is one of the drawbacks of coreless motors, is suppressed.

The operational amplifiers 38a, 39b and transistors 14c, 14d in FIG. 8a have the effect of converting the magnetic energy stored in the armature coil into output torque when the current supply is stopped at the point indicated by the dotted line 34b in FIG. 11. Exactly the same as the example.

It is also obvious that the means shown in FIGS. 8b and 8c can be applied to this embodiment, so a description thereof will be omitted.

FIG. 8d shows an embodiment in which the armature coil is energized back and forth. In FIG. 8d, the same symbols as in FIG. 8a indicate members that perform the same functions. The outputs of points F and D in FIG. 8a are input to the terminals 49a and 49b.

Symbol B indicates the armature coils 5a, 5b,
5c, 5d or armature coil 11a, 11
b, 11c, and 11d are connected in parallel or in series. Transistors 47a, 47b,
47c and 47d are well-known transistor bridge circuits for energizing the armature coil B back and forth.

The outputs of the operational amplifiers 38a and 39a serve as base inputs of transistors 47a and 47b, respectively, via inverting circuits 44a and 44b.

At startup, as in the previous embodiment, since the input to one terminal of the operational amplifiers 38a and 39a is at a low level, the conduction of the transistors 47a and 47b is alternated every 180 electrical degrees, and therefore the armature coil B is energized back and forth.

It is also the same as the previous embodiment that it can be started automatically by cogging torque.

At startup, the operational amplifiers 38a and 39a
Since the input to one terminal of the armature coil B is a reference voltage (voltage shown as a dotted line 16a in FIGS. 5 and 6), the initial and final stages of energization of the armature coil B are cut off, increasing efficiency. If the same armature current is applied as in the embodiment of FIG. 8a, the output torque will be doubled, but the increase in efficiency will be the same as in the previous embodiment.

When transistor 47a is conductive and armature coil B is energized to the right, transistor 48a is conductive, but is not energized because a reverse voltage is applied. At the end, when armature coil B is de-energized, the stored magnetic energy is released through transistor 48a, and the torque due to this current is positive, increasing efficiency.

The situation is exactly the same when the transistor 47b is conductive and the armature coil B is energized to the left, and at the end of the energization, the magnetic energy is released by the transistor 48b and becomes an effective torque, increasing the efficiency. It has a coercive effect.

〔effect〕

When the device of the present invention is used as a drive source for an axial flow fan with an input of about 1 to 2 watts, the efficiency is about 50% to 55% compared to the efficiency of a conventional device of the same shape, which is about 35%. %, and noise is reduced.
Naturally, the heat generated by the electric motor itself is reduced, and the cooling effect can be increased. It is effective to apply the present invention to a small one-phase motor in which copper loss accounts for a large portion of the loss. Further, since the magnetic energy stored in the armature coil can be effectively converted into output torque, there is an effect that the efficiency can be further increased by 3 to 4%.

[Brief explanation of drawings]

Figure 1 is a front view of the device of the present invention with a magnetic core, Figure 2 is a developed view of the salient poles of the magnetic rotor and fixed armature, and Figure 3 is the device of the present invention without a core. FIG. 4 is a front view of the fixed armature of the device; FIG. 4 is an explanatory diagram of the magnetic rotor; FIGS. 5 and 6 are graphs of the output voltages at points E, F, H, and I in FIG. 8; Fig. 7 is a developed view of the magnetic pole and Hall element, Fig. 8 is a energization control circuit diagram of the armature coil,
FIG. 9 is a graph of the output torque and armature current of the embodiment shown in FIG. 1, and FIG. 10 is an explanatory diagram showing changes in magnetic flux between the magnetic poles of the magnet rotor and the opposing salient poles.
FIG. 11 shows graphs of the output torque and armature current of the embodiment of FIG. 3, respectively. 1, 28... Rotating shaft, 2, 28a... Ball bearing, 3, 15... Cylinder, 4, 4a, 4b, 4c,
4d...Fixed armature and its salient pole, B, 5a, 5
b, 5c, 5d, 11a, 11b, 11c, 11
d... Armature coil, 6, 30... Magnetic rotor, 6a, 6b, 6c, 6d, 30a, 30
b, 30c, 30d...magnetic pole, 7, 7a, 7b,
7c, 7d... Salient poles for generating cogging torque,
13... Mild steel cup, 8a... Hall element, 10
a, 10b...Power supply positive electrode, 38a, 38b, 39
a, 39b... operational amplifier, 14a, 114b,
14c, 14d, 17a, 17b, 45, 46,
47a, 47b, 47c, 47d, 48a, 48
b...transistor, 15a, 15b...output curve at point E, 16b, 16c, 20, 20a...output curve of Hall element 8a, 16a...standard voltage,
18a, 18b... Output curve at point H, 19a, 1
9b... Output curve at point I, 22a, 22b... Torque curve, 23... Cogging torque curve, 25
a, 25b, 25c, ..., 26a, 26b, 2
6c, 35a, 35b, 36a, 36b... Current curve, 32, 33... Direction of magnetic flux, 31... Mild steel disc, 12a, 12b, 12c... Terminal, 8...
Mild steel piece, 43... Monostable circuit, 44, 44a, 4
4b...Inversion circuit.

Claims (1)

[Scope of Claims] 1. A magnetic rotor and a fixed armature, which automatically stop the magnetic rotor avoiding the dead center position when the armature coil attached to the fixed armature is not energized. In a one-phase semiconductor electric motor having a starting means, N and S magnetic poles of equal width are arranged alternately along the circumferential surface of a magnet rotor, and the magnetic field is strongest in the center of the magnetic poles, and An even number of N, S magnetic poles are magnetized so that their strength gradually decreases as they move to the lower part, and an N, S magnetic pole is fixed to the fixed armature side facing the N, S magnetic poles with an air gap between them.
A position detection device including one magnetoelectric transducer 8a that can obtain first and second position detection signals proportional to the strength of the magnetic field of each of the magnetic poles, and a reference voltage that is maintained at zero voltage at the time of startup and set. Electric circuit A that outputs and maintains the reference voltage that has risen to the set voltage after a period of time
and the first and second comparison circuits 38 in which the first and second position detection signals each serve as one input signal, and the reference voltage mentioned above serves as another common input signal.
a, 39a, the first and second position detection signals, and the reference voltage that has risen to the set voltage and is held, are compared by the first and second comparison circuits, and only the section where the reference voltage has been exceeded is compared. is 120 in electrical angle with amplified output
The electrical angle amplified by the third and fourth position detection signals, which are arrayed rectangular wave electrical signals with a width smaller than 180°, and the first and second comparison circuits when the reference voltage is zero voltage. a transistor 14a connected in series to the armature coils 5a and 5c;
The transistor 14b connected in series to the armature coils 5b and 5d is supplied with power from the DC power supply, and the third and third position detection signals are input to the base of the transistor 14a, so that conduction is established for the width of each position detection signal. , a fourth at the base of the transistor 14b,
An energization control circuit C receives a fourth position detection signal and controls the energization of the armature coils by making the width of each position detection signal conductive, and the armature coils 5a, 5
c, the fourth position detection signal becomes the base input, conduction is made by the width of the position detection signal, and when the armature coils 5a and 5c are de-energized, the stored magnetic energy is transferred to the current. The transistor 14c is connected in parallel to the armature coils 5b and 5d, and the third position detection signal becomes the base input, and the armature coils 5b and 5d are electrically connected by the width of the position detection signal. A transistor 14d converts the accumulated magnetic energy into a current and causes the discharge to disappear when the current to the transistor 5d is cut off.
A one-phase semiconductor motor characterized by comprising: 2. A one-phase motor that is equipped with a magnetic rotor and a fixed armature, and has a self-starting means that stops the magnetic rotor avoiding the dead center position when the armature coil attached to the fixed armature is not energized. In a semiconductor electric motor, N and S magnetic poles of equal width are arranged alternately along the circumferential surface of a magnet rotor, and the magnetic field is strongest at the center of the magnetic poles and increases as it moves toward both ends. An even number of N, S magnetic poles magnetized so that the strength gradually decreases, and an N, S
The first and second examples are the strength of the magnetic field of each magnetic pole.
One magnetoelectric transducer 8 that can obtain a position detection signal of
A position detection device including A, and an electric circuit A that maintains the reference voltage at zero voltage at the time of startup and outputs and maintains the reference voltage that has increased to the set voltage after a set time.
and the first and second comparison circuits 38 in which the first and second position detection signals each serve as one input signal, and the reference voltage mentioned above serves as another common input signal.
a, 39a, the first and second position detection signals, and the reference voltage that has risen to the set voltage and is held, are compared by the first and second comparison circuits, and only the section where the reference voltage has been exceeded is compared. is 120 in electrical angle with amplified output
The electrical angle amplified by the third and fourth position detection signals, which are arrayed rectangular wave electrical signals with a width smaller than 180°, and the first and second comparison circuits when the reference voltage is zero voltage. Four transistors 47a, 47b, 47c, 47d are connected to the third and fourth position detection signals, which are arrayed rectangular wave electric signals with a width of 100°C, to energize the one-phase armature coil B in a reciprocating manner. A transistor bridge circuit consisting of a transistor bridge circuit, a DC power supply supplied to the transistor bridge circuit, and base input control of transistors 47a and 47c located diagonally of the transistor bridge circuit by third and third position detection signals. conduction for the width of each position detection signal, energizing the armature coil B in one direction, and transistor 4 at the other diagonal position.
7b and 47d based on the fourth and fourth position detection signals, and conducts the armature coil B by the width of each position detection signal to energize the armature coil B in the opposite direction; connected in parallel to
The fourth position detection signal becomes the base input, and when the width of the position detection signal is conductive and the armature coil B is de-energized, the transistor 4 converts the stored magnetic energy into a current and causes the discharge to disappear.
8a and armature coil B in parallel, the third position detection signal becomes the base input, conduction is made for the width of the position detection signal, and when the armature coil is de-energized, the accumulation occurs. A one-phase semiconductor motor characterized by comprising a transistor 48b that converts magnetic energy into a current and causes discharge to disappear.