JPH0418327B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention utilizes the characteristics of a leaky tripod transformer,
The present invention also relates to a phase control circuit that switches AC power in stages by phase control.

Conventionally, all AC power phase control circuits using triaxes and the like were directly connected to an AC power source, and 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, the
As shown in the figure, when using a photocoupler non-contact relay, a power supply is required for operation input, and even if on/off control is possible, phase control is not possible, so a separate control circuit is required for phase control.
Further, even if a step-down transformer is used as shown in FIG. 2, it is necessary to insulate the pulse generation circuit from the triac gate circuit. Moreover, all of the above conventional examples have many expensive parts, and when remote control is performed using non-contact low voltage operation, it is necessary to use expensive parts such as step-down transformers, pulse transformers, photocouplers, reed relays, etc. that are separately insulated from the power supply. In addition, the wiring of the power supply and operation circuit was complicated, resulting in an expensive device.

In order to eliminate such drawbacks of the conventional circuit, the present invention uses a leaky tripod transformer in which each coil is completely insulated and can reduce the number of coils, and a switch is provided on the low voltage secondary coil side. A firing angle control section is provided on the next coil side, and multiple firing angles are fixed as needed, switched by a switch, and applied as an output signal to control the firing angle of the bidirectional three-terminal thyristor. The purpose is to control and switch AC power in stages.

Embodiments of the present invention will be described below based on the drawings.

FIG. 3 is a circuit diagram showing an AC power phase control circuit according to an embodiment of the present invention. Before entering into the explanation of this embodiment circuit, the leakage type tripod transformer 1 used here will be briefly explained.

The leaky tripod transformer 1 has outer legs 2, 4 and a central leg 3 as shown in FIG.
A secondary coil 7 is wound around the secondary coil 6 and the center leg 3, respectively, so that a low voltage is induced in the secondary coil and the tertiary coil.

In the embodiment circuit shown in FIG. 3, both ends of the primary coil 6 of the leaky tripod transformer 1 are connected to a power source 12, and the secondary coil 7 is connected to a switch 13.
Further, both ends of the tertiary coil 8 are connected to a full-wave rectifier 14, and a value switching circuit 20 is connected between the two ends of the tertiary coil 8 on the DC side, including two resistors 15, 16 and a switch 17 connected in series. A capacitor 21 is connected in series, and the two resistors 15 and 16 are connected in series.
The connection point is connected to the gate G of the NPN type/PNP type transistor combination circuit 22, the anode A is connected to the connection point of the resistance value switching circuit 20 and the capacitor 21, and the cathode K is connected in parallel to the power supply 12 via the resistor 23. The two-way three-terminal thyristor 25 is connected to the terminal _T1 of the two-way three-terminal thyristor 25 in series with the load 24, and the negative pole of the direct current is connected to the two-way three-terminal thyristor 2.
This is a phase control circuit connected to the gate G of No. 5 and to the terminal T ₁ via a capacitor 26, respectively. A series circuit of a capacitor 27 and a resistor 28 is connected between the terminals T ₂ and T ₁ of the bidirectional three-terminal thyristor 25, and the capacitor 29 is connected in parallel to the tertiary coil 8.

Next, the operation of the leaky tripod transformer 1 will be explained. In Fig. 4, when the primary coil 6 is connected to the power supply _{12 and energized, assuming that the secondary coil 7 is open, most of the primary magnetic flux φ 1 is} centered as shown by the solid line. A low voltage is induced by passing through the leg 3 and interlinking with the secondary coil 7, but since the magnetic resistance of the outer leg 4 with the gap 5 is extremely large, only a small amount of leakage magnetic flux φ ₁ '' passes through the outer leg 4 and the tertiary coil Only a very small voltage is generated in the secondary coil 7.
When short-circuited with switch 13, a short-circuit current flows and a secondary magnetic flux φ ₂ in the opposite direction to the magnetic flux φ ₁ ′ is generated, and the outer leg 4
The magnetic flux φ ₂ ″ on the side and the magnetic flux φ ₂ ′ on the outer leg 2 are divided as shown by dotted lines, and the composite magnetic flux of the magnetic flux φ ₁ ″ increased by the short circuit and the magnetic flux φ ₂ ″ is transferred to the outer leg 2 where the gap 5 is located. Since it passes through the leg 4, the tertiary coil 8 has a voltage higher than the power supply voltage.
A voltage delayed by a little less than 360 degrees is generated. That is, this tertiary voltage is considered to be a voltage (thin line A in FIG. 6) that is slightly more advanced than the power supply voltage (bold line A in FIG. 6). As described above, the leaky tripod transformer 1 has a characteristic of inducing a voltage in the tertiary coil 8 in response to a short circuit in the secondary coil 7, which is approximately in phase with the power supply voltage and has a slightly leading voltage. Third
The example circuit shown in the figure utilizes this characteristic.

Next, the operation of the embodiment circuit shown in FIG. 3 will be explained. In addition, FIG. 6 shows the voltage waveforms of various parts of the example circuit. The voltage between the terminal T ₁ and the gate G of the bidirectional three-terminal thyristor 25, C is the load applied voltage, and D is the voltage between the terminal T ₁ and the gate G of the bidirectional three-terminal thyristor 25 when the switch 17 is closed. Similarly, shows the waveform of the load applied voltage.

When the switch 13 is open, the tertiary coil 8
Since no voltage is induced in the tertiary coil 8 and the abnormal voltage is absorbed by the capacitor 26, the phase control circuit connected to the tertiary coil 8 does not operate at all. Now switch 1
3 is closed, a voltage is induced in the tertiary coil 8, which is converted into DC by the full-wave rectifier 14. capacitor 2
1 is charged through the resistor 19 or the combined resistance of resistors 18 and 19 (by opening or closing the switch 17), and is connected to the NPN type, PNP type transistor combination circuit 22.
becomes the anode voltage, increases and resistors 15, 16
When the voltage exceeds the voltage of the gate G of the NPN type, PNP type transistor combination circuit 22, which is applied with a divided voltage, the gate current flows from the anode A to the gate G of the PNP
type transistor _Q2 becomes conductive. The collector current of PNP transistor Q ₂ is the same as that of NPN transistor Q ₁
The base current becomes conductive to the NPN transistor _Q1 , and the collector current flows to strengthen the gate current of the PNP transistor _Q2 . transistor type
Since the current gain of both Q ₁ and Q ₂ increases as the current increases, they quickly reach a positive feedback state, exhibit negative resistance and conduct, so the charge in the capacitor 21 is rapidly discharged and the switch 17 By switching the resistance value, charging and discharging is repeated from 1 to 10 times during a half cycle, and a pulse signal synchronized with the power supply frequency (FIG. 6, B and D) is generated, which is transmitted through the resistor 23 to the bidirectional three-terminal thyristor 25. Apply it to the terminal _T1 as a positive side and to the gate G as a negative side. Therefore, the bidirectional three-terminal thyristor 25 is fired in accordance with the phase angle of the pulse signal, and the voltage is phase-controlled by the switch 17 in two or three stages (C or C in FIG. 6). Since e) is applied to the load 24, AC power can be controlled in stages. Further, as shown in FIG. 5, the negative pole of the full-wave rectifier 14 is connected to the terminal T1 of the bidirectional three-terminal thyristor ₂₅ , and the cathode K of the NPN type, PNP type transistor combination circuit 22 is connected to the voltage dividing resistor 2.
Bidirectional three-terminal thyristor 25 through 3,30
When connecting the voltage dividing point to the terminal T ₁ of the gate G,
The positive pulse voltage is applied to the gate G of the bidirectional three-terminal thyristor 25, and the negative pulse voltage is applied to the terminal _T1.Although the voltage is applied completely opposite to the case shown in Fig. 3, the sensitivity is slightly lower, but The operation is similar to that shown in the figure, and the phase of AC power can be controlled in stages.

The series circuit of a capacitor 27 and a resistor 28 in FIG. 3 protects the bidirectional three-terminal thyristor 25 by absorbing the induced overvoltage generated by opening and closing the bidirectional three-terminal thyristor 25 and the overvoltage input from the power supply. It is.

Since the circuit of the present invention has the above-mentioned effects, it can be used in a wide range of industrial equipment and consumer equipment. For example, a consumer electronics vacuum cleaner requires power consumption of about 600W due to its strong suction power for normal cleaning, but if it is used for curtains, etc., it will instantly suck in the curtains and become unusable. Therefore, it is possible to easily reduce the power consumption to about 300W and use the suction power by using the circuit of this invention.

The present invention has a number of features and effects as described above, and in summary, there is no risk of electric shock because the power source and the low voltage operating circuit are isolated by using a leaky tripod transformer.

Full firing is possible because the triax is fired at zero cross using the slight advance phase shift, which is a characteristic of the leaky tripod transformer.

By switching the resistance value, AC power can be controlled in stages by phase control.

Since the tertiary voltage of the leakage type tripod transformer is used as the power source for the phase control circuit, no separate power source is required.

Since this is a phase control circuit using a leaky tripod transformer with a gap in the third leg, false firing will occur if the signal voltage applied to the gate of the bidirectional three-terminal thyristor is ≈0 when the switch (or variable resistor) is opened. There is no fear.

Instead of using separate input and output transformers as in the past, a leaky tripod transformer is used, so the transformer can be provided in a small, lightweight, and low-cost manner, and as a result, it naturally reduces the load of AC motors in application circuits. The phase control circuit unit can also be manufactured in a small size, light weight, and low cost.

Since a leaky tripod transformer is used, the cost of the transformer is 3/4 that of conventional ones.
The space required for installation is only 70%, and this has great economic value for Japan's home appliance industry, considering the production scale of several million units per year.

Since both the secondary and tertiary voltages are low and the current is small, the tripod transformer can be made compact.Furthermore, the phase control section is composed of a combined circuit of PNP type and NPN type transistors, so electrical parts are inexpensive. Therefore, the entire phase control circuit can be made inexpensive.

etc., and the effects of the present invention are extremely large.

[Brief explanation of drawings]

Figures 1 and 2 are circuit diagrams of a conventional example, Figure 3 is a circuit diagram of an AC power phase control circuit showing an embodiment of the present invention, and Figure 4 shows a gap in the monopod used in the present invention. FIG. 5 is a circuit diagram showing another embodiment of the phase control circuit, and FIG. 6 is a waveform diagram of various parts for explaining the operation of the embodiment of the phase control circuit of FIG. 3. In the diagram: 1: Tripod transformer, 5: Gap, 6: Primary coil, 7: Secondary coil, 8: Tertiary coil, 11:
Non-magnetic material, 20: Resistance switching circuit, 21: Capacitor, 22: NPN/PNP transistor combination circuit, 25: Bidirectional three-terminal thyristor, Q ₁ :
NPN type transistor, _Q2 : PNP type transistor.

Claims (1)

[Scope of Claims] 1. A leaky tripod transformer in which one leg of the tripod core is an open leg with a gap, and a primary coil connected to an AC power supply is wound around one non-open leg, and the other non-open leg is wound with a primary coil connected to an AC power source. A secondary coil is wound around the leg, a tertiary coil is wound around the open leg, a switch is connected to the secondary coil, both ends of the tertiary coil are connected to a full-wave rectifier, and a coil is connected in series between both ends of the DC side. Two resistors connected to , a resistance value switching circuit including a switch and a resistor, and a series circuit of a capacitor are connected in parallel, and the connection point of the two series-connected resistors is connected to the base of the PNP type transistor and the NPN type transistor. and the collectors are connected to the base of a PNP type transistor of a transistor combination circuit whose collectors are connected correspondingly to each other,
The emitter of the PNP type transistor of this transistor combination circuit is connected to the connection point of the resistance value switching circuit and the capacitor, and the emitter of the NPN type transistor of the transistor combination circuit is connected to a load connected in parallel to the power supply via the resistor. Connected to terminal T ₁ of a bidirectional three-terminal thyristor in series,
A phase control circuit for AC power using a leaky tripod transformer in which the negative pole of DC is connected to the gate G of the bidirectional three-terminal thyristor. 2 Gate G of the bidirectional three-terminal thyristor
are directly connected to the DC negative pole of the full-wave rectifier, and are respectively connected to the terminal _T1 via a capacitor. control circuit. 3 directly connect the DC negative pole of the full-wave rectifier to the terminal T ₁ of the bidirectional three-terminal thyristor;
The emitter of the NPN transistor of the transistor coupling circuit is connected to the terminal _T1 of the bidirectional three-terminal thyristor via a voltage dividing resistor, and the voltage dividing point thereof is connected to the gate G of the bidirectional three-terminal thyristor. An alternating current power phase control circuit using a leaky tripod transformer according to claim 1.