JPS61269692A - Synchronizing speed variable single-phase induction motor apparatus - Google Patents

Abstract

PURPOSE:To selectively use either one of the original synchronizing speed and the peripheral speed of 1/2 of the synchronizing speed by providing changeover switches in 2-phase windings and a capacitor. CONSTITUTION:The first windings 10A are selectively connected at one end through a changeover switch 14A to either one terminal of a power source 12. Simultaneously, the second windings 10B are selectively connected at one end through a changeover switch 14B to either one terminal of the power source 12. The other terminals of the windings 10A, 10B are further connected at one through the third changeover switch 14C and a capacitor 16 at the other directly to the other terminal of the power source 12. The third changeover switch is switched at every 1/2 cycle synchronously with the power source voltage, and the first and second switches are switched by displacing 1/2 cycle at every one cycle of the power source voltage synchronously with the switching operation. By this arrangement, a synchronous speed corresponding to one half is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a capacitor run type single-phase induction motor device.

[Technical background of the invention and its problems]

For example, when changing the refrigeration capacity of the refrigeration cycle in a relatively small capacity air conditioner according to the refrigeration load, the compressor motor One method is to vary the fii[i2 frequency. Frequency converters are widely used as variable frequency power supplies.

In particular, a stationary frequency converter is easy to control and can continuously change the output frequency, so it is convenient for realizing finely tuned air conditioning. However, since a continuously variable output frequency type frequency converter has a large number of parts, it not only has a high failure rate but also is expensive.

-・On the other hand, depending on the application, it may not necessarily be a continuously variable output frequency, but may be
Since a certain degree of comfort can be obtained by operating the compressor motor only in combination with a frequency equivalent to 2, such an operating method is often recommended from the viewpoint of low cost and low failure rate.

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances, and is a novel synchronous speed variable type single-phase induction lightning i! The purpose is to provide a second machine device.

[Summary of the invention]

In order to achieve the above object, the present invention includes first and second windings that are spatially arranged 90' apart from each other by an electrical angle to constitute stator magnetic poles, and a coil that is provided for each winding and connected to a power source. first and second changeover switches capable of individually switching connection polarity; a phase advance capacitor; and a third phase advance capacitor selectively connected in series to the first winding or the second winding. changeover switch, and in addition to the first synchronous speed when each changeover switch is fixed to either side, the third changeover switch is activated every 1/2 cycle in synchronization with the power supply voltage. The first synchronous speed is controlled by switching the first and second changeover switches while shifting the first and second changeover switches by 1/2 cycle for each cycle of the power supply voltage in synchronization with the switching operation. This is a variable synchronous speed type single-phase induction municipal motor device characterized in that a second synchronous speed corresponding to 1/2 can be obtained.

[Related technology]

As can be seen from the summary of the invention, the present invention applies to a known capacitor run type single-phase inductive electric current! The technology of the IJJ 81 device is applied, and in order to explain the principle, a well-known capacitor run type induction electric rock device will first be explained with reference to FIG. 10 and subsequent figures.

As shown in Figure 10, the known single phase! ! tIJffi! I
JIfi10 consists of a main winding 10M, an auxiliary winding 10H spaced apart from the main winding 10M by an electrical angle of 90', a rotor 10R, and a main winding 10H connected in series to the auxiliary winding 10H to form stator magnetic poles. Equipped with a phase capacitor 10G,
Voltage is supplied from the power supply 12 directly to the main winding 10M and to the auxiliary winding 10H via the capacitor 10C to generate the desired torque. The current of main winding 10M is I
When the current in the auxiliary M auxiliary winding 10H is 'l-1, the current (H) is approximately 90° smaller than the current (M) due to the action of the capacitor 10C, as shown in Figures 11(a) and (b). 'Become advanced. In addition, the frequency or synchronization of both types of flow is determined by the power supply 12.
matches that of . In FIG. 11, sections 1.2.3.4 are set every 90" with the main winding current IM as a reference,
Magnetic flux due to main winding current φ Auxiliary winding current 111
If the magnetic flux due to M M is φ, then 1-(
M.H The rotating magnetic field formed also rotates once per cycle of the power supply, corresponding to the current sections 1 to 4 shown in FIG. 11 and the sections 1 to 4 shown in FIG. 12.

[Embodiments of the invention]

FIG. 1 shows an embodiment of the present invention.

This electric motor has a rotor 10R similar to that in Fig. 10,
First windings 10 spatially spaced apart by an electrical angle of 90°
The present invention includes a single-phase induction motor 10 having a stator winding consisting of A and a second winding 10B. First winding 10
One end of A is selectively connected to one end of the power supply 12 via a changeover switch 14A. Similarly, the second winding 10
One end of B is selectively connected to one end of the power supply 12 via a changeover switch 14B. Both windings 10A.

The other ends of the power supply 10B are further connected to the other end of the power supply 12 through the third changeover switch 14C, one through the capacitor 16, and the other directly to the other end of the power supply 12.

By switching the selector switch 14C, the capacitor 1
6 is inserted in series, the winding is switched. Changeover switch 14
Δ~14G is the control device 2 in synchronization with the power supply phase detected by the phase detection circuit 18 connected to both ends of the power supply 12.
Switching operation is performed by 0.

In the motor of FIG. 1, the capacitor 16 has a winding of 10A.
10B, but in any case, the current in the winding to which the capacitor 16 is connected is the same as the current in the winding to which the capacitor 16 is not connected. As shown in Figures (a) and (b), the phase is advanced by 90°.

Now, when the changeover switches 14A, 14B, and 14G are in the parallel line positions shown by the solid lines in the figure, the current I in the winding 10A is
It is assumed that the directions of the magnetic flux φA caused by the current 10B of the winding 108 and the magnetic flux φB caused by the current 10B of the winding 108 are in a relative relationship as shown in FIG. 4, that is, the magnetic flux φA leads the magnetic flux φB by 90'. Here, selector switch 14A to 14G
If these are fixed to either side, it is possible to obtain a Hundensalan type single-phase induction motor device which operates on exactly the same principle as the known one shown in FIG. is 12Of/P, where f is the power supply frequency and P is the number of motor poles.

Next, the changeover switches 14A to 14G are operated by the control device 20 in synchronization with the power supply as shown in FIG. In FIG. 3, the section corresponds to the section (90°) in FIG. 2, and A in the column ``Capacitor-connected winding''.

B indicates which side of the winding 10A or 10B the capacitor 16 is connected to, the winding 10A.

The polarity of 10B is indicated by the changeover switch 14.
When A and 14B are at the solid line (parallel line) position shown in the figure, the positive polarity is shown as positive, and when they are at the dashed line (diagonal line) position, the opposite polarity is shown as reverse. By operating the changeover switches 14A to 14G in this manner, the rotating magnetic field of the motor rotates by 2 cycles r1 of electric m voltage as shown in FIG. 4, and accordingly, the synchronous speed NS of the motor
is 1/2 of that when the changeover switch is not changed, that is, 60f/P.

Switching between the two types of synchronous speeds described above is performed by inputting N to the control device 20.
S switching commands are used to fix each changeover switch or to switch them synchronously as shown in FIG. line 10A,
This can be achieved by making the connection polarity of 108 relatively opposite to that described above.

Note that when the frequency f supplied to the electric motor is changed, the V/f ratio is generally controlled to be constant so that the magnetic flux density is kept constant. The above-mentioned measure to reduce the synchronous speed by half is also equivalent to reducing the frequency f to 1/2 when considering the motor magnetic flux, and therefore, in that case, it is generally desirable to also reduce the supply voltage to 1/2. FIG. 5 shows the on/off circuit 22 lit! for this purpose. 12 and an electric motor. There may be several specific examples of the on/off pattern by the on/off circuit 22. FIGS. 6 and 8 show typical examples thereof.

In Figure 6, the current is turned on and off in units of 1/4 cycle of the power supply, that is, intervals of 1.2, etc. In this case, the rotating magnetic field is also 2 cycles of the power supply, as shown in Figure 7. It is clear that the motor still rotates one revolution and the motor voltage decreases by half.

In Figure 8, on-off is repeated more precisely in each section corresponding to 1/4 cycle of the power supply, and the rotating magnetic field in this case repeats on-off with shorter synchronization as shown in Figure 9. Become something.

In the embodiments described above, the case of a two-pole motor was illustrated, but it is possible to apply the present invention to four or more types of motors.

(Effects of the Invention) As described above, according to the present invention, it is possible to selectively use either the original synchronous speed or a 1/2 synchronous speed by applying the known single-phase induction motor structure. Furthermore, the device of the present invention can be realized at a lower cost and with higher reliability than the frequency control system using the conventional frequency converter U.

[Brief explanation of drawings]

FIG. 1 is a circuit connection diagram showing one embodiment of the present invention, FIG. 2 is a waveform diagram for explaining the winding current of the device shown in FIG. 1, and FIG.
The figure is a switch changeover diagram showing an example of the switching mode of each changeover switch in the device shown in Fig. 1, Fig. 4 is an explanatory diagram of the rotating magnetic field of the electric motor shown in Fig. 1, and Fig. 5 is a circuit showing a modified embodiment of the present invention. Connection diagrams, Figures 6 and 8 are waveform diagrams showing current waveforms of different on/off patterns of the device in Figure 5, Figures 7 and 9 are rotating magnetic fields corresponding to the currents in Figures 6 and 8. An explanatory diagram of
Fig. 10 is a circuit connection diagram of a known capacitor run type single-phase induction motor device, Fig. 11 is a waveform diagram of both winding currents in the device of Fig. 10, and Fig. 12 is a rotation corresponding to the current shown in Fig. 11. It is an explanatory diagram of a magnetic field. 10... Single phase induction motor, 10A, 10B... Winding, 10R... Rotor, 12... Power supply, 14A, 14
B. 14G... Selector switch, 16... Phase advancing capacitor, 18... Phase detection circuit, 20... Control device, 2
2...On/off circuit. Applicant's agent Ino Establishment Figure 1 Figure 5

Claims (1)

[Claims] 1. First and second windings spaced apart by an electrical angle of 90° to form stator magnetic poles, and a first winding provided for each of these windings and capable of individually switching the connection polarity to the power supply. and a second changeover switch, a phase advance capacitor, and a phase advance capacitor that connects the phase advance capacitor to the first winding or the second winding.
a third changeover switch selectively connected in series with the winding of the switch, in addition to the first synchronous speed when each changeover switch is fixed to either side, the first The third changeover switch is operated to change over every 2 cycles, and in synchronization with the changeover operation, the first and second changeover switches are shifted from each other by 1/2 cycle every cycle of the power supply voltage. A variable synchronous speed single-phase induction motor device, characterized in that a second synchronous speed corresponding to 1/2 of the first synchronous speed can be obtained by performing a switching operation.