JPS6026495A - Rotating device of alternating magnetic field - Google Patents

Abstract

PURPOSE:To reduce the sizes and weights of a core of a magnetic path and a winding by separating the production of a magnetic field, its rotation by a conveying path and different frequency different from the modulation wave, thereby relatively reducing the number of turns of the windings. CONSTITUTION:An exciting winding 1 is connected between an intermediate tap of the secondary winding of a single phase transformer 5 connected to a carrier power source 4 and the intermediate point of two sets 6, 7 and 8, 9 of parallel transistors. When the conductions of the transistors 6, 7 and 8, 9 are switched, a carrier of the same phase as that from the transformer 5 is altered in the direction of the current and applied to the winding 1. Voltage dividing resistors 11- 14 are inserted in series with the modulation wave power source 10, the voltages of 12, 13 are applied in parallel with the base circuits of 6, 7 and 8, 9, and amplified. Accordingly, the carrier voltage is amplitude modulated by the modulating frequency.

Description

[Detailed Description of the Invention] Generally, in a synchronous motor, two of these are used instead of a filter set type excitation winding.
Although it is possible to generate a rotating magnetic field by replacing the excitation windings with phase-type excitation windings, an angular difference of 90° is required between the two sets of excitation winding arrangements and the phases of the excitation voltages. If an electronic switch were inserted on the excitation power source side and opened and closed synchronously at high speed, the rotating magnetic field would be forcibly interrupted, resulting in an alternating magnetic field with an intermittent frequency. This alternating magnetic field induces an alternating voltage by electromagnetic induction in the synchronously rotating DC field winding on the rotor side, and an electromagnetic force is generated between the alternating current and the alternating magnetic field. The same condition can be obtained by applying an excitation voltage with an intermittent waveform to the excitation winding instead of using a switched electronic switch. The solid line in FIG. 1(a) shows the excitation voltage waveform in this case for one set of excitation windings. That is, this is an example when special amplitude modulation is applied such that the peak value of the carrier wave shown by the solid line is equal to the instantaneous value of the modulated wave shown by the dotted line, and each is represented by an approximate sine waveform. If the carrier frequency component (cl) is extracted from this excitation voltage waveform, the modulation frequency component (bl remains, tc) is also amplitude modulated with the same period as (b), but this is the most typical carrier wave AC It represents the voltage amplitude modulation waveform.Similarly, the carrier frequency component (d
If l is extracted, (C) and tdl have the same shape, but there is a phase difference of 900 between the amplitude changes. Also, the second section simply shows the relationship of the arrangement between each winding in this case.
It is a diagram. Stator side excitation winding (IH) consisting of rotor structure
21 has the same number of turns (1), the excitation winding axes of the two sets cross each other perpendicularly, and the rotor side DC field winding (b) is particularly represented by a short circuit, so it is actually DC excitation. There will be no current. The air gaps in the core magnetic path between the stator and rotor, which are arranged concentrically, are uniform, and short-circuited windings (b)
Assuming that the rotor is rotated at a constant speed while opening the circuit and exciting it with a constant voltage at the carrier frequency, the excitation winding (
Naturally, an induced voltage having a waveform corresponding to (C) (d) is generated at IN21. On the other hand, if a voltage with the same waveform is applied to the excitation winding (IH2) to excite it, a constant voltage will be induced in the rotating rotor side winding (3), and the relationship will be relatively the same. . However, the magnetic field is generated by the excitation voltage corresponding to (cl (dl), and the alternating magnetic fields generated by the excitation voltages with the same effective value and the excitation windings with the same number of turns are perpendicular to each other. Even if the magnitude changes, the magnitude of the vector-like composite alternating magnetic field remains constant, and this is in a state where it rotates synchronously with the modulation frequency.This is the so-called alternating rotating magnetic field, which has a constant instantaneous value. The difference is that in this case, the magnetic field is rotated while the instantaneous value is alternating, compared to a conventional rotating magnetic field in which the magnetic field is rotated.

The excitation winding +11 (21 does not have the waveform shown by the solid line in Fig. 1 (al), but the excitation voltage corresponding to C1 (d
This means that the rotor side winding (6) is
As shown in the figure, the electromagnetic force generated between the short circuit current flowing when the short circuit is short-circuited and the composite alternating magnetic field becomes a rotational force that rotates the short circuit winding (6). However, due to the rotation of the composite alternating magnetic field, this rotational force is directly replaced by the synchronous rotational force of the rotor. The reason for this is that the rotational force of the short-circuit winding is proportional to the short-circuit current, and the short-circuit current is proportional to the induced voltage, and the induced voltage is the effective linkage of the composite alternating magnetic field. Therefore, the short-circuit winding (b) is rotated synchronously following the rotation of the composite alternating magnetic field. Furthermore, the magnetomotive force generated by the short circuit current is vectorially canceled out by the composite alternating magnetic field that rotates synchronously with the short circuit winding at an angle of deflection and causes a load current to flow through each excitation winding due to transformer action. This means that there is no so-called armature reaction,
Since an increase in the isolateral excitation reactance is impossible, there is no effect of limiting the short-circuit current.

The present invention relates to a power supply device necessary for generating an alternating rotating magnetic field in the above case, and its electronic circuit is (C)
It is composed of a type of amplifier that can stably maintain the excitation voltage waveform corresponding to (d). That is, Figure 5 is a connection diagram showing an embodiment of the present invention, in which the secondary winding of a single-phase transformer (5) connected to a predetermined carrier wave power source (4) is equipped with a center tap, and conducts current in both directions. Two sets of possible parallel transistors (6
) (7) and (8) +9+ are inserted in series in an electric bridge circuit, in which the excitation winding (1) shown in Figure 2 is connected between the intermediate tag corresponding to the load. There is. By alternating the energization of each parallel transistor (61 (71 and (8) (9)), the carrier wave of the same phase is transferred from the transformer (5) to the excitation winding (1) by changing the current direction in the opposite direction. Also, a voltage dividing resistor (11) is added to the modulated wave power source (1D).
(14) are inserted in series, (12) and (13) are inserted in series.
) are applied in parallel to the base circuits (6), (8), (7), and (9), respectively, and amplified. Therefore, while the carrier wave voltage is amplitude modulated at the modulation frequency, an excitation voltage with a waveform corresponding to (C1) is generated in the excitation winding (1). Two sets of insulating transformers are connected in parallel to the excitation winding (1). Container (15X1
The secondary winding 6) includes a switching transistor (17X1a) for switching the current direction, and a filter (21) and (22) via (19X20). This is Figure 1+c
By converting the excitation voltage corresponding to Resistor (26) and parallel (24) close to the voltage waveform of the power supply
However, the carrier wave peak value included in the excitation voltage (1) can be automatically made proportional to the instantaneous voltage value of the modulated wave power source (1o) by the negative feedback effect. Also in this case +
6j (71 and (8+ +91 energization is (12) (13
) is switched synchronously every time the direction of the instantaneous voltage value of the modulated wave power source (1o) is reversed, so there is no risk of short-circuiting the secondary circuit of the transformer (5). (17) and (18) can be performed in synchronization with this energization switching. However, in Fig. 3, the carrier frequency is modulated and the phase distortion given to the modulated wave by the filter is reduced, and the voltages of (11) and (14) are reduced to (17X1'
8) In addition to the pace of (t9) and (20), almost the same effect is performed. Also, all the diodes used in FIG. 6 are intended to block reverse voltages acting on each transistor, and each transistor may have to be replaced with a Darlington connection or other multi-stage amplifier circuit. The same electronic circuit as in Fig. 6 is adopted for the excitation winding (2) in Fig. 2, but its modulated wave power source is (10).
A voltage with a phase difference of 90' is required.

The transformer (5) is shared because the excitation winding (11
(2) This is to maintain the carrier wave current flowing in the same phase in the polar direction so as not to generate a rotating magnetic field at the carrier frequency.

In Figure 3, there are two sets of symmetrical circuits excluding the electric bridge circuit, which are parallel transistors (6) and (7), respectively.
), and by switching the current flow between (8) and (9), it is necessary to make the carrier wave current flowing through the excitation winding (1) into a symmetrical AC waveform, so to speak, full-wave rectification is performed. It is used as a circuit. However, even though the carrier wave currents in the excitation winding (11 (21) are all in the same phase, in reality, the voltage of the transformer (5) changes direction and is applied every half cycle of the modulated wave, so the excitation winding The waveform of each carrier in the line is inverted.

This is necessary to create an alternating rotating magnetic field.
This means that each excitation voltage vector-wise goes in the opposite direction for each half period of the modulation wave, and in reality, (61+71 and +8j
This is done by energization switching of +91. Further resistance (2
3) Adjust the magnitude of the voltage of the excitation winding (1) by replacing (24) with a voltage dividing resistor and balancing some of the voltages with the voltages (12) and (16), respectively. is also possible.

The present invention is highly reliable because it is entirely composed of electronic circuits, and the feature is that the generation of the magnetic field and its rotation are separated at different frequencies by the carrier wave and the modulation wave, and there is no difference between them. It can be adjusted independently without interference. In this respect, in the case of a synchronous motor, a common excitation voltage with the same frequency is used, so the magnetic transmission frequency is selected to be constant, but by selecting a high frequency, the number of turns of each winding can be relatively reduced. This has the effect of making the winding smaller and lighter, similar to the iron core of a road. In this case, the modulation frequency can be adjusted arbitrarily regardless of this to control only the rotational speed of the magnetic field. All the load current of the excitation winding (1) in Fig. 6 is supplied via the transformer (5), and the modulated wave power source that becomes the input of the amplifier is hardly affected by the load current, so the frequency Control is easy and suitable for joint control. Although the embodiment was directed to a two-phase excitation winding, it can be similarly applied to a three-set excitation winding, and the principle of the present invention remains basically the same. When adopting the excitation voltage with the special waveform shown in the solid line in Figure 1 (al), in addition to the alternating rotating magnetic field that generates Figure 1 + CI as well as (d), the conventional rotating magnetic field shown in Figure 1 (bl etc.) Although magnetic fields coexist, their coexistence is not a problem because they are completely the same.In general, electronic circuits are characterized by the fact that it is easy to make slight changes to the circuit for the same purpose. For example, if we remove transistors (7) and (9) in Figure 3, half of the symmetrical circuit described above becomes unnecessary, and becomes (13X14) (+5) (+6) (19
)(20)(22)(24) can all be omitted. The electronic circuit in this case is simple, but the carrier current flowing through the excitation winding (1) corresponds to a half-wave rectifier circuit,
An alternating rotating magnetic field is generated by the alternating current component included in the carrier current. Although the output is reduced, it is suitable for relatively small-capacity equipment.

[Brief explanation of the drawing]

FIG. 1 is an example showing a carrier wave excitation voltage waveform to which special amplitude modulation has been applied, and the relationship between the carrier wave and modulated wave components contained therein. If the rotor side DC field winding is particularly short-circuited to the stator side excitation winding part of the same type as a two-phase synchronous motor that applies an excitation voltage corresponding to this, the relationship between each winding arrangement can be easily explained. Figure 2 shows what is shown in Figure 2. Figure 6 is the second
An embodiment of an electronic circuit connected to a set of excitation windings necessary for generating an alternating rotating magnetic field by each excitation winding shown in the figure, (1) (2) ... fixed Child side excitation winding, (b)・
... Rotor side shorted winding, (4) ... Carrier wave power supply,
+51 (15) (+ 6)...Transformer. (6)(c(81+91(17)(18)(19)(2
0)...Transistor. (10) Modulated wave power supply, (11) (+2) (13) (14
)(23)(24)・・・Resistance. (21X22)...Filter. nose + 1@ki 21 ship), 31 too

Claims (1)

[Claims] In a bridge circuit, two sets of parallel transistors that can conduct current in both directions are inserted in series in the secondary winding of a single-phase transformer connected to a predetermined carrier wave power source. The excitation winding between the points connecting the When an electric circuit consisting of a multi-phase excitation winding and a modulated wave power source is arranged in parallel corresponding to the number of phases, and the voltage of the modulated wave power source is applied to the gate of a parallel transistor and amplified, each phase excitation winding A carrier wave with the same phase generates an excitation voltage whose amplitude is modulated by the phase of the modulated wave frequency difference, and the excitation voltage is also changed by simultaneously switching the switching transistor in synchronization with the alternation of energization between the two sets of parallel transistors. The voltage converted from is further filtered by removing the carrier frequency component to approximate the modulated wave to the voltage waveform of the modulated wave power source, and then automatically intervenes in series with the modulated wave power source in the opposite direction. An alternating magnetic field rotating device characterized by constantly rotating the carrier wave peak value of an excitation voltage synchronously with the frequency of a modulated wave power source while balancing both voltages.