JPH0568187B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an AC power phase control circuit having a low voltage control section completely isolated from a power source.

Conventionally, all AC power phase control circuits using triaxes and the like were directly connected to an AC power source as shown in FIG. 1, and therefore there was a risk of electric shock when controlling the phase. To solve this problem, when performing remote control from the low voltage operation circuit side, when using a photocoupler non-contact relay as shown in Figure 2, a power supply (DC or AC) is required for operation input, making it difficult to perform on/off control. However, since phase control is not possible with this type, a separate phase control circuit is required if phase control is to be performed. Furthermore, even if a step-down transformer is used to control the phase at a secondary low voltage as shown in FIG. 8, it is necessary to insulate the pulse generation circuit from the gate circuit of the triac. All of the above conventional examples have a large number of parts, and when remote control is performed using non-contact low voltage operation, it is necessary to use a step-down transformer, pulse transformer, photocoupler, reed switch, etc. that is separately insulated from the power supply.
Another disadvantage is that the wiring for the operating power source and operating circuit is complicated and expensive.

In view of these drawbacks of conventional circuits, the present invention provides a phase control circuit and an on/off switch that are completely insulated from the AC power source on the secondary side of a leakage type or composite type tripod transformer, and also provides electromagnetic coupling with the secondary coil. A circuit is provided in which the output signal of the tertiary coil is supplied between the terminal T1 of the triac ₁₈ and the gate G, and the phase of the load power is controlled by the phase control of the secondary circuit.

The configuration of the present invention will be explained based on the circuit shown in FIG. 4, which is an embodiment thereof. First, the configuration of the tripod transformer used in the present invention will be described. The tripod transformer 1 used here has two types of tripod core configurations even though they have the same characteristics.
4. It has a central leg 3 and a gap 5 on the outer leg. A primary coil 6 is wound around the outer leg 2, a secondary coil 7 is wound around the central leg 3, and a tertiary coil 8 is wound around the outer leg 4 with a gap so that a low voltage is induced. This type is called a leaky tripod transformer. Tripod transformer 1 in Figure 6 is 2
Two inner iron cores 9 and 10 are isolated and coupled with a non-magnetic material 11 to form a tripod core.A primary coil 6 is wound around the outer leg 2, and a secondary coil 7 is wound around the wide central leg 3. A tertiary coil 8 is wound around the other outer legs 4 in such a way that a low voltage is induced therein. This type is called a composite tripod transformer. The tripod transformers shown in FIGS. 5 and 6 differ only in the tripod core, but their functions and effects are substantially the same as will be described later.

Next, FIG. 4 shows an embodiment of the circuit of the present invention, which uses the tripod transformer 1, in which a series circuit of a load 12 and a triax 13 is connected to a power source 14, and the tripod transformer 1 is used.
One end of the secondary coil 6 is connected to the power supply side of the load 12 or the triax side of the load 12 as shown in _FIG . One end of the tertiary coil 8 is connected to the connection point between the primary coil 6 and the resistor 15, and the other end is connected to diodes 16, 1 connected in parallel with opposite polarities.
7 to the gate G of the triax 13, and a triax 18, a variable resistor 19 and a capacitor 20 are connected to both terminals of the secondary coil 7 of the central leg 3.
It is characterized by having a phase control circuit A in which the series circuits of and the switch 21 are connected in parallel, and the connection point of the variable resistor 19 and the capacitor 20 is connected to the gate G of the triac 18 via a trigger element (for example, SBS) 22. This is an AC power phase control circuit using a tripod transformer. A series circuit of a resistor 23 and a capacitor 24 is connected in parallel to the triax 13 as a surge absorber. Further, if necessary, the current limiting resistor 25 of the triac 18 and the charge current limiting resistor 26 of the capacitor 20 may be connected in series.

The operation of the circuit of the present invention will be explained. When the power supply voltage is now applied to the circuit, a low voltage (for example, 24V) set in the secondary coil 7 is induced, and the capacitor 20 is charged through the variable resistor 19.
When the terminal voltage of 0 becomes equal to or higher than the breakover voltage of the trigger element 22, the trigger element 22 exhibits negative resistance, so the electricity stored in the capacitor 20 is discharged through the gate of the triac 18 and the terminal _T1. fires. The change in the variable resistor 19 causes a delay in the time the electric voltage charged in the capacitor 20 reaches the breakover voltage of the trigger element 22, and the trigger element 22, such as SBS or diac, changes approximately every half cycle of the secondary voltage. Since the pulse is oscillated, the triac 18 is fired in both directions, that is, every half cycle, and the triac 18 is fired depending on the phase angle of the pulse. Therefore, the secondary coil 7 is repeatedly short-circuited at a constant phase depending on the position of the variable resistor (change in resistance value) with respect to the input voltage. This is the effect of the phase control circuit A.

Therefore, to explain the action of the tripod transformer 1, as shown in FIGS. 5 and 6, if the secondary coil 7 is open, the primary magnetic flux φ ₁ generated by the primary coil 6 is expressed as a solid line. It passes through the iron core to form a magnetic circuit. In FIG. 5, the magnetic flux φ ₁ ' mainly passes through the central leg 3, and the outer leg 4 with the gap 5
Only a very small magnetic flux φ ₁ ″ flows through the center leg 3. Therefore, a set low voltage (e.g. 24V) is generated in the secondary coil 7 of the central leg 3, and a very small amount of magnetic flux φ 1″ flows in the tertiary coil 8 of the outer leg 4. Only a small voltage is _generated . In FIG. Coil 7 has a set low voltage (e.g.
24v) is generated, and almost no voltage is generated in the tertiary coil 8 of the outer leg 4.

Now, when the secondary coil 7 is short-circuited by the switch 21, a secondary current flows in FIG. 5, and a secondary magnetic flux φ ₂ is generated in the opposite direction to the primary magnetic flux φ ₁ ' as shown by the dotted line.
A magnetic circuit is formed by dividing the magnetic flux φ ₂ ″ toward the primary coil 6 and the magnetic flux φ ₂ ″ toward the tertiary coil 8. Therefore, the tertiary coil 8 has φ ₁ ″, which has increased due to the short circuit. The _combined magnetic flux of Also in FIG. 6, a short circuit current flows through the secondary coil 7, and a secondary magnetic flux _φ2 is generated in the opposite direction to the primary magnetic flux _φ1 , forming a magnetic circuit in the inner iron core 10 with low magnetic resistance. It interlinks with the tertiary coil 8 to generate a predetermined low voltage. The three-legged transformer 1 shown in FIGS. 5 and 6 both has the effect of generating a low voltage in the tertiary coil 8 by short-circuiting the secondary coil 7. Moreover, the 8th
As shown in the spectrum diagram in the figure, the voltage is the power supply voltage.
The voltage E ₃ lags behind E ₄ by nearly 360 degrees, that is, it is a voltage that is considered to be slightly ahead of the power supply voltage E ₄ . Since the tripod transformer 1 has the above characteristics, the secondary coil 7 is short-circuited to the tertiary coil 8 when the secondary coil 7 is short-circuited or when the short-circuit is opened under phase control by the phase control circuit A. It appears as a voltage corresponding to the short circuit current when Therefore, if the phase is controlled by the variable resistor 19 of the phase control circuit A mentioned above, a voltage corresponding to the phase will appear in the tertiary coil 8, and the anti-parallel diodes 16,
The voltage is applied to the gate G of the triac 13 through the resistor 17, and the resistor 15 is connected in series with the primary coil 6.
is inserted, a composite voltage E ₄ with the _voltage drop 1 ₁ R is applied as shown in FIG.
It fires according to the phase angle of . Therefore, the power of the load 12 connected in series with the triax 13 can be phase controlled. By adjusting the resistor 15, the voltage drop 1 ₁ R changes and the phase of the composite voltage E ₄ can be adjusted, so full ignition is possible.

Also, considering the case where the variable resistor 19 is at its maximum, the charging time will be very long, and the breakover voltage of the trigger element 22 will not be reached during a half cycle, and the voltage will be reversed in the next half cycle, causing the trigger element 22 to be in a state of no operation. Since the secondary coil 7 is not short-circuited, the tertiary coil 8 has almost no voltage.
The excitation voltage ₀ of the primary coil 6, which is approximately 90 degrees behind the power supply voltage, flows through the resistor 15, and a voltage drop of ₀ R appears, but the number of primary windings and the resistance value are determined in advance so that the triator 13 does not ignite. is set, so it will not ignite, and there is also a voltage drop in the forward direction of the anti-parallel diodes 16 and 17 (approximately 0.7V regardless of the current), which prevents malfunction of the triac 13 and increases safety. There is. Further, the resistor 26 has the function of preventing malfunction of the triac 13 due to voltage generated in the tertiary coil 8 due to rapid charging of the capacitor 20.

Note that the oscillation of the phase control circuit A generally varies from 0 to 0 depending on the resistance value of the variable resistor during a half cycle of the secondary voltage.
More than ten pulses are generated, but in this circuit, the triac 18 fires at the first pulse of a half cycle, short-circuiting the secondary coil 7, so only the first pulse is generated. The first pulse causes a tertiary pulse similar to the secondary current to be generated in the tertiary coil 8.
The power of the load can be controlled by controlling the phase of the triax 13. The circuit shown in FIG. 7 also has substantially the same effect, although the triac 13 is short-circuited.

When the present invention is applied to a vacuum cleaner, which is a consumer appliance, the on/off operation can be performed using the switch 21 at hand (or, if wired as shown in Figure 9, only 2 wires are required), and the variable resistor 19 is attached at hand to rotate the fan motor. Since the number can be controlled, there is an advantage that the rotation speed can be changed depending on the application.

As mentioned above, the present invention utilizes the characteristics of a leaky type or composite type tripod transformer, so there is no risk of electric shock, there is no need for a separate power source, and the power can be adjusted by phase control. There is. In addition, the tripod transformer requires less current in each coil and can be made small and inexpensive, and the circuit of the present invention has extremely few electrical parts, so it can be commercialized small and inexpensively, making it particularly suitable for consumer appliances, such as vacuum cleaners.
Its features and effects are extremely remarkable, such as being able to turn it on and off as well as adjust the suction power.

[Brief explanation of the drawing]

Figures 1, 2 and 3 are circuit diagrams of conventional examples;
Fig. 4 is a circuit diagram of an embodiment of the present invention, Fig. 5 is a block diagram of a leaky tripod transformer, Fig. 6 is a block diagram of a compound tripod transformer, and Fig. 7 is a diagram of the wiring change in the circle in Fig. 4. An embodiment circuit diagram, FIG. 8 is a vector diagram of the present invention, and FIG. 9 is another circuit diagram of the operating circuit. In the figure, 1...tripod transformer, 6...primary coil, 7
... Secondary coil, 8... Tertiary coil, 13, 18... Triack, 15... Resistor, 16, 17... Diode, 19... Variable resistor, 20... Capacitor, 21...
Switch, 22...Trigger element.

Claims (1)

[Claims] 1. A primary coil 6 for supplying commercial power to the outer leg, a secondary coil 7 to the central leg, and 3 coils to the other outer legs.
A leaky or composite tripod transformer 1 around which a secondary coil 8 is wound; a load 12 whose one end is connected to a commercial power source 14; one terminal _T2 is connected to the other end of the load 12; a first triax 13 whose terminal _T1 is connected to a commercial power supply 14; a resistor 15 connected between the commercial power supply connection end of the first triax 13 and one end of the primary coil 6 and the tertiary coil 8; a second triax 18 connected to the secondary coil 7; a series circuit of a variable resistor 19 and a capacitor 20 connected in parallel to the second triax 18; a switch 21 connected in parallel to the series circuit; a trigger element 22 connected between the coupling point of the variable resistor and the capacitor and the gate electrode of the triax 18; and a reverse polarity parallel connection connected between the other end of the tertiary coil 8 and the gate electrode of the triax 13. An AC power phase printing circuit using a tripod transformer consisting of a pair of diodes. 2. An AC power phase control circuit using a tripod transformer according to claim 1, wherein one end of the primary coil of the tripod transformer is connected to a connection point between the load 12 and the triax 13.