JPH10207557A - Alternating current stabilized power supply, and reduced voltage starter using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely apply a specific voltage to a load even in the case of wide-range voltage variation by detecting an input or output voltage and performing ON/OFF control over a switch according to the detection result, and holding the output voltage constant within a specific permissible range. SOLUTION: A main coil 1 and a switching coil 2 are wound around the same iron core. In this state, an induced current flows through the switching coil 2, but the voltage between 1st external connection terminals 10-1 and 10-2 is applied to the load 50 almost as it is. Then, when the voltage applied between the 1st external connection terminals 10-1 and 10-2 rises above a constant permissible limit, the voltage applied to the load 50 also rises above the permissible range. For the purpose, a voltage control circuit 4 is connected to the coil 1 by turning on a voltage control command switch 21 to make a power circuit operate as an autotransformer, thereby making automatic control so that the voltage between 2nd external connection terminals 10-3 and 10-4 is held within the desired permissible range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stabilized AC power supply for single-phase or multi-phase AC, and more particularly to a stabilized AC power supply using a tapped autotransformer.

[0002]

2. Description of the Related Art There are some stabilized AC power supplies whose voltage can be adjusted steplessly, but they are generally expensive. Therefore, a tap switching type transformer having a tap for voltage adjustment provided on a primary or secondary winding has been proposed.

[0003] However, these tap-changing transformers also require windings on the primary and secondary sides of the common iron core, so that the process is complicated, and it is not necessarily inexpensive. I was

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an inexpensive AC transformer having a simple winding transformer having a simple winding. It is to provide a stabilized power supply. Thus, in the conventionally known autotransformer, if the coil or the combination of the taps is automatically selected or switched in accordance with the input voltage, an accident such as burning of the coil or an abnormal voltage occurs. It has not been possible to construct an AC stabilized power supply that requires automatic switching. The gist of the present invention is to provide a novel alternating current comprising an autotransformer having a plurality of coils and a control circuit capable of selecting or switching a combination of the coils or taps safely and automatically according to an input voltage. It is to provide a stabilized power supply.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a transformer for voltage adjustment, in which a main coil, a switching coil, and at least one, and preferably a plurality of pressure regulating coils are wound around a common iron core. One terminal of the input line is connected to one of the input lines, the other terminal is connected to one of the output lines, and the other input line is connected to the other input line. Further provided with a switching coil, a voltage adjustment command switch inserted in series between the switching coil and the main coil, and a switching coil short-circuit switch, regardless of the state of the voltage adjustment command switch. A voltage adjustment command circuit comprising a switching coil short-circuit circuit capable of short-circuiting both terminals of the coil; and a voltage adjustment command circuit comprising a coil selection switch, wherein a voltage adjustment coil is selected from time to time. A coil selection circuit connected in series, between either the one terminal and the input-output common connection terminals of the main coil, and a voltage adjustment command circuit and the coil selection circuit,
An autotransformer, which is connected in series and further connected in parallel with a resistor circuit formed by connecting a desired resistor and a resistance selection switch in series with one of the coil selection switches, is used. An AC stabilized power supply configured to detect the input or output voltage of a device, and to control the opening and closing of switches provided in the above circuits in accordance with the detection result, so that the output voltage is kept constant within a predetermined allowable range. Is achieved by

[0006] The feature of the present invention is that, despite the use of an autotransformer, the above-mentioned voltage adjustment command switch, switching coil short-circuit switch and resistance selection switch are appropriately opened and closed to achieve safe and secure operation. An object of the present invention is to make it possible to smoothly select and switch a voltage adjusting coil. The AC stabilized power supply according to the present invention can be configured not only for a single phase, but also for a three-phase or more polyphase, and for a step-down voltage used when an input voltage is a high voltage exceeding an allowable range. In the opposite case, it can be provided as an AC stabilized power supply for both boosting and step-up / step-down operation. Also, since large sequence control of output voltage is possible, supply of motor starter, heating device, etc. It can be used for voltage sequence control.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an outline of an AC stabilized power supply according to the present invention. FIG. 2 is a circuit diagram showing one configuration example of an autotransformer used in the AC stabilized power supply shown in FIG. FIG. 4 is a circuit diagram showing an example of a configuration of an autotransformer using a tapped coil used in an AC stabilized power supply according to the present invention. FIG. 4 is an autotransformer different from that shown in FIG. FIG. 5 is a circuit diagram showing an example of a configuration of a transformer, and FIG. 5 is a circuit diagram showing an example of a configuration of an autotransformer different from those shown in FIGS. 3 and 4, and FIG. FIG. 7 is a circuit diagram showing a configuration example of an autotransformer used in an AC stabilized power supply.
And FIG. 8 is a circuit diagram showing an example of a configuration of an auto-transformer for buck-boost operation, which is different from that shown in FIG. FIG. 9 is a circuit diagram showing
FIG. 3 is a circuit diagram showing a configuration example of an autotransformer used in an AC stabilized power supply for three-phase star connection.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, description will be made sequentially from FIG. FIG. 1 shows a basic configuration of a stabilized single-phase AC power supply using a tapped autotransformer according to the present invention. In FIG. 1, reference numeral 10 denotes an autotransformer, which comprises a main coil 1, a switching coil 2, a pressure adjusting coil 3, and a voltage adjusting circuit 4 wound on a common iron core (not shown).

Reference numeral 20 denotes a voltage detection circuit for detecting the output voltage of the autotransformer 10, and reference numeral 30 denotes a control necessary for maintaining the output voltage within a predetermined allowable range according to the detection result of the voltage detection circuit 20. An operation circuit for generating a signal, an ignition circuit 40 for opening and closing each switch provided in the voltage adjustment circuit 4 in accordance with a control signal of the operation circuit 30 to maintain an output voltage within a certain allowable range; 50 is a load circuit.

In this embodiment, the first external connection terminal 10-1,
10-2 is on the power supply side, and the second external connection terminals 10-3 and 10-4 are on the load side.
Is reversible, and the first external connection terminals 10-1 and 10-2 can be used as the load side, and the second external connection terminals 10-3 and 10-4 can be used as the power supply side. However, in this case, if the illustrated state is for step-down, when the input and output are reversed, the state is for step-up.

In the illustrated example, it is assumed that the main coil 1, the switching coil 2 and the pressure adjusting coil 3 are all wound in the same polarity. As will be described later, the number of turns of the main coil 1 is extremely smaller than those of the switching coil 2 and the pressure regulating coil 3. The autotransformer 10 is a four-terminal network, and each pair of first external connection terminals 10-1 and 10-2.
In this embodiment, the first external connection terminals 10-1 and 10-2 are connected to an external AC power source, and the second external connection terminals 10-3 and 10-4. Terminals 10-3 and 10-4 are connected to load 50.

One terminal 1-1 of the main coil 1 is connected to one of the first external connection terminals 10-1 and the other terminal 1--1.
2 is connected to one of the second external connection terminals 10-3, and a load current flows through the main coil 1. Voltage adjustment command input terminal 4 of voltage adjustment circuit 4 including switching coil 2 and pressure adjustment coil 3
1 is connected to an output line connected to the other terminal 1-2 of the main coil 1, and the input / output common terminal 4-5 is connected to the other first external connection terminal 10-2 and the second external terminal. Connection terminal 10-4
Is connected.

The output voltage to the load 50 is detected by the voltage detection circuit 20, and the detected data is sent to the arithmetic circuit 30,
The arithmetic circuit 30 controls the opening and closing of each switching element built in the voltage adjusting circuit 4 via the ignition circuit 40 based on the data to maintain the input voltage to the load 50 within a predetermined allowable range. is there. The voltage of the first external connection terminals 10-1 and 10-2 is normal, and the second external connection terminals can be used without voltage adjustment.
When the voltage between 10-3 and 10-4 is within the allowable range, as shown in FIG. 1, the voltage adjustment command switch 21 is off, and the voltage adjustment circuit 4 The autotransformer 10 is disconnected from the power supply line, does not function as a transformer, and is in a so-called through state.

Since the main coil 1 and the switching coil 2 are wound on the same iron core, an induced current flows through the switching coil 2 in this state, but the switching coil 2 does not consume more energy than iron loss. Since the impedance of the main coil 1 is extremely small as compared with that of the load 50, the voltage of the first external connection terminals 10-1 and 10-2 is supplied to the load 50 almost as it is. Thus, when the voltage supplied between the first external connection terminals 10-1 and 10-2 is higher than a certain allowable limit, the voltage supplied to the load 50 also increases beyond the allowable range, The voltage adjustment command switch 21 is turned on, the voltage adjustment circuit 4 is connected to the main coil 1, the power supply circuit is operated as an autotransformer, and the voltage of the second external connection terminals 10-3 and 10-4 is set to a desired level. Adjust automatically to keep within range.

FIG. 2 shows the simplest configuration example of the voltage adjustment circuit 4.
Is shown in Here, this circuit will be described as a step-down circuit. That is, when the voltage between the second external connection terminals 10-3 and 10-4, that is, the voltage supplied to the load 50 exceeds the allowable range, the voltage is reduced to a voltage within the allowable range and supplied. It shall be. In the illustrated example, the voltage adjustment circuit 4 includes a voltage adjustment command circuit 4-2, a coil selection circuit 4-3, and a resistance circuit 4-4, and these circuits are as illustrated. Is connected between the voltage adjustment command input terminal 4-1 and the input / output common terminal 4-5. That is, the voltage adjustment command circuit 4-2 and the coil selection circuit 4-3 are connected in series, inserted between the voltage adjustment command input terminal 4-1 and the input / output common terminal 4-5, and connected to the resistance circuit 4-4. Is
Connected in parallel with the coil selection switch 31.

The voltage adjustment command circuit 4-2 includes a switching coil 2
And a switching coil short circuit 23 including a voltage adjustment command switch 21 and a switching coil short circuit switch 22. The voltage adjustment command switch 21 is provided between the main coil 1 and the switching coil 2; Reference numeral 22 is inserted at a position where the switching coil 2 can be short-circuited regardless of the voltage adjustment command switch 21. The coil selection circuit 4-3 is connected in series with the above-described voltage adjustment command circuit 4-2, and includes one voltage adjustment coil 3 for voltage adjustment and a coil selection switch.
31 and a coil path switch 32.
Is connected to the main coil 1 and the switching coil 2. The resistance circuit 4-4 is configured by connecting a resistance 41 and a resistance selection switch 42 in series, and is connected in parallel with the coil selection switch 31.

The voltages of the first external connection terminals 10-1 and 10-2 are normal, and the second external connection terminals 10-3 and 10-3 can be used without voltage adjustment.
When the voltage between 10 and 4 is within the allowable range, as shown in FIG. 2, all switches other than the switching coil short-circuit switch 22, that is, the voltage adjustment command switch 21 and the coil selection switch 31 , 32 and the resistance selection switch 42 are off, and only the switching coil short-circuit switch 22 is on. As described above, in this state, the voltage regulation circuit 4 is disconnected from the power supply line to the load 50, and the autotransformer 10 does not function as a transformer, and is in a through state, that is, the input voltage Is output as it is.

Since the main coil 1 and the switching coil 2 are wound around the same iron core, an induced current flows through the switching coil 2 in this state, but the switching coil 2 does not consume more energy than its iron loss. Since the impedance of the main coil 1 is extremely small as compared with that of the load 50, the voltage of the first external connection terminals 10-1 and 10-2 is supplied to the load 50 almost as it is. Thus, if the voltage supplied between the first external connection terminals 10-1 and 10-2 becomes excessively high, the voltage supplied to the load 50 also exceeds the allowable range and increases. The ignition circuit 40 is activated by the signal, the switch of the voltage adjustment circuit 4 is switched according to the following procedure, the power supply circuit operates as an autotransformer, and the second external connection terminal 10-3,
The voltage of 10-4 is reduced.

At this time, the voltage adjustment command switch 21 is turned on and the switching coil short-circuit switch 22 is turned off. Prior to switching these switches, first, the resistance selection switch 42 and the coil path switch 33 are turned on. , A resistor 41 is inserted in series in the coil circuit, and in this state, the switching coil short-circuit switch 22 is turned off first, then the voltage adjustment command switch 21 is turned on, and the pressure regulating coil 3 is connected to the switching coil 2. Coil selection switch when using
When the pressure adjustment coil 3 is cut off by turning on the coil path switch 33 and turning off the coil path switch 33, the coil selection switch 31
Is turned off, the coil path switch 33 is turned on, and after the switching of these switches is completed, the resistance selection switch 42 is turned off. Thus, it is desirable that the switching of the series of switches be performed at the zero cross point of the current.

The reason why the switching coil short-circuit switch 22 is turned off before the voltage adjustment command switch 21 is turned on is that if the voltage adjustment command switch 21 is turned on while the switching coil short-circuit switch 22 is on, the switching coil 2, an excessive current flows through the switching coil 2 and the switching coil 2 instantaneously burns out, so that such a situation is avoided. The reason why the coil path switch 33 is turned on and the resistor 41 is inserted into the circulating current circuit of the pressure regulating coil 3 is to prevent the core from becoming saturated and generating an abnormal voltage in each coil. That is,
If this resistor 41 is inserted in series with the coil circuit, the circuit will be in a state like a current transformer having a load resistance, and when the voltage adjustment command switch 21 is turned on, this resistor 41 Becomes the current limiting resistance of the closed circuit including
The occurrence of abnormal voltage due to supersaturation of the iron core is prevented. The insertion of the resistor 41 into the coil circuit is always performed in advance even when the coil selection switch 31 and the coil path switch 33 are switched again or when the voltage adjustment command switch 21 is turned off. In this case, the resistance 41
Is connected to limit the short-circuit current when the coil selection switch 31 and the coil path switch 33 are simultaneously switched.

As shown in FIG. 1, the voltage supplied to the load 50 is detected by the voltage detection circuit 20, and the output data is sent to the arithmetic circuit 30. When the supply voltage to the load 50 becomes excessive, the arithmetic circuit 30 determines how to select and switch the coil based on the current ON / OFF state of each switch and the voltage detection data, A command pulse is sent to the arc circuit 40 to switch the coil selection switch 31, the coil path switch 33 and the switching coil short-circuit switch 22, change the turns ratio of the autotransformer 10, and control the output voltage. Since the switching of the switch is performed according to the above procedure, an overcurrent flows through each coil,
The switching of the switches is performed smoothly without the occurrence of abnormally high voltage, and the voltage supplied to the load 50 is always kept within a certain allowable range. Although an example in which a single coil is used as the pressure adjusting coil 3 has been described above to explain the principle of the present invention, actually, a plurality of coils are used, and the combination of the number of turns and the polarity of the coils are appropriately adjusted. The above-mentioned configuration constitutes an AC stabilized power supply for boosting used when the supply voltage decreases, and for step-down and step-up / down used in the opposite case.

In the preferred embodiment of the present invention, it is recommended to use a tapped coil as the pressure adjusting coil 3 because the control circuit is simple. Thus, FIG.
FIG. 1 shows such an autotransformer 10A. The main coil 1, the switching coil 2, the voltage adjustment command circuit 4A-2, and the resistance circuit 4A-4 used here are the main coil 1, the switching coil 2, and the voltage adjustment command circuit 4-2 shown in FIG.
And the resistance circuit 4-4. A coil with a tap is used as the pressure adjustment coil 3 in the coil selection circuit 4A-3. This coil with tap is tap 3-1.
3-2 and 3-3.
1, 3-2 and 3-3 include coil selection switches 31, 3
2. The switch 33 for the coil path is connected, and the contact on the opposite side of the switch from the pressure regulating coil 3 is short-circuited by the short circuit 34 and connected to the voltage adjustment command circuit 4A-2.
The resistance circuit 4A-4 includes a resistance 41 and a resistance selection switch 42, and is connected in parallel with the coil selection switch 31 described above. The operation of this circuit will be clear from the foregoing description. FIG. 3 shows a so-called through state when the supply voltage to the load 50 is within a normal range.
In this state, the voltage adjustment command switch 21 is off, the switching coil short-circuit switch 22 is on, the voltage adjustment circuit 4 is disconnected from the power supply line from the main coil 1 to the load 50, and the input voltage is almost unchanged.ゝ Supplied to load 50. Thus, when the supply voltage to the load 50 rises above the allowable limit, the voltage adjustment command switch 21 is turned on, and the switching coil short-circuit switch 22 is turned off. First, the resistor selection switch 42
And the coil selection switch 32 or 33 is turned on, and the resistor 41 is inserted in series into the circulating current circuit of the pressure regulating coil 3;
In this state, first, the switching coil short-circuit switch 22 is turned off, and then the voltage adjustment command switch 21 is turned on. Further, when all or some of the tapped coils used as the pressure adjusting coil 3 are connected to the switching coil 2 and used, the coil selection switches 31 and 32 and the coil path switch 33 are appropriately turned on. The resistor selection switch 42 is turned off, and after these switch switching is completed, the resistance selection switch 42 is turned off. Now, the number of turns of each coil, N ₂ pressure regulating coil 3 tap between N ₁ switching coil second terminals 2-1 and 2-2 between the main coil 1 terminal 1-1, 1-2 3-1, 3-2 the N ₃ voltage supplied between N ₄ first external connection terminal 10-1 between the tap 3-2 and 3-3 between, E
₁₁ , E ₁₂ or E ₁₃ , where E ₁₁ <E ₁₂ <E ₁₃ Assuming that the voltage output between the second external connection terminals 10-3 and 10-4 is E, the selected coil selection switch 31, The transformation ratios Φ ₃₁ , Φ ₃₂ and Φ ₃₃ corresponding to ₃₂ and ₃₃ are as follows.

When the coil selection switch 31 is on, the windings of all the coils are in series and the input voltage is divided by the three coils, so that Φ ₃₁ = E ₁₁ / E = (N ₁ + N ₂ + N ₃ + N ₄ ) / (N ₂ + N ₃ + N ₄ ) (1) When the coil selection switch 32 is on, the winding between the taps 3-1 and 3-2 of the pressure regulating coil 3 is cut off, Since the winding of the coil 1, the winding of the switching coil 2, and the winding between the taps 3-2 and 3-3 of the pressure adjusting coil 3 are in series, and the input voltage is divided by the windings of these coils, Φ ₃₂ = E ₁₂ / E = (N ₁ + N ₂ + N ₄ ) / (N ₂ + N ₄ ) (2) When the coil selection switch 33 is on, the winding of the pressure regulating coil 3 is cut off and the main coil 1 Winding and switching coil 2
And the input voltage is divided by the windings of these two coils, Φ ₃₃ = E ₁₃ / E = (N ₁ + N ₂ ) / (N ₂ ) (3)

Now, in order to adjust the voltage by 2%, ie, Φ ₃₁ = 1 / 0.98 E = 0.98E ₁₁ (4) Φ ₃₂ = 1 / 0.96 E = 0.96E ₁₂ (5) Φ ₃₃ = 1 / In order to set 0.94 E = 0.94E ₁₃ (6), if N ₁ = 10T, the equations (3) and (3)
From (6), N ₂ = 156.7T From formulas (2) and (5), N ₄ = 83.3T From formulas (2) and (5), N ₃ = 240T is obtained. With this configuration, for example, the input voltage
Even when the voltage fluctuates between 100 and 108 V, the voltage fluctuation of the output voltage E can be maintained within 0 to 2%.

The circuit configuration of the voltage adjusting circuit 4 is not limited to that shown in FIG. 3, but can be changed, for example, as shown in FIG. Main coil 1, switching coil 2 and pressure regulating coil 3 used in autotransformer 10B shown in FIG.
Are the same as those described above, but the voltage adjustment circuit 4B has a circuit configuration different from that of the voltage adjustment circuit 4A.

That is, the voltage adjustment circuit 4B is similar to the voltage adjustment instruction circuit 4A-2, the coil selection circuit 4A-3, and the resistance circuit 4A-4.
2, consisting of a coil selection circuit 4B-3 and a resistance circuit 4B-4, the connection state of which is changed. However, it will be apparent from the above description that the voltage adjustment circuit 4B functions in the same manner as the above-described voltage adjustment circuit 4, and the description thereof is omitted here. In short, in the autotransformer according to the present invention, a coil having a small number of turns is used as a main coil, one switching coil and a plurality of pressure regulating coils are wound around the same core as the main coil, and the switching coil is used as a main coil. 1 and both terminals can be switched between a state in which both terminals are short-circuited and a state in which both terminals are opened and connected in series with the main coil 1, and each of these coils can be selectively selected according to the supply voltage. In order to prevent the core from becoming oversaturated when the switch is switched, it is configured so that it can be connected in series with the main coil. In addition, the exciting current of the main coil is supplied to the load, and the input voltage is stepped up or down by the main coil and the coil connected in series to maintain the output voltage to the load within a certain allowable range. Is shall.

In the above description, the autotransformer 10 is of the step-down type. However, the input and output of the circuits shown in FIGS. 3 and 10-4 are connected to the power supply as input terminals, and the first external connection terminals 10-1 and 10-2
It can be readily understood that if the output terminal is connected to the load 50, it can be used as a boost type. In this case, Φ ₃₁ = E ₁₁ / E = (N ₂ + N ₃ + N ₄ ) / (N ₁ + N ₂ + N ₃ + N ₄ ) instead of the above equations (1), (2) and (3). (11) Φ ₃₂ = E ₁₂ / E = (N ₂ + N ₄ ) / (N ₁ + N ₂ + N ₄ ) (12) Φ ₃₃ = E ₁₃ / E = (N ₂ ) / (N ₁ + N ₂ ) (13) ) Holds. In this case, assuming that the voltage is adjusted by 2%, Φ ₃₁ = 0.98 (14) Φ ₃₂ = 0.96 (15) Φ ₃₃ = 0.94 (16), and N ₁ = 10T N ₂ = 156.7T N ₄ = 83.3T N ₃ = 240T is obtained.

Another configuration example of the step-up type transformer is shown in FIG. In the autotransformer 10C, a voltage adjustment circuit 4C having the same configuration as the above-described voltage adjustment circuit 4 is used. The autotransformer 10C is different from the autotransformer 10 shown in FIG. 3 in that the main coil 1C is connected to the switching coil 2C and the pressure regulating coil 3C in the opposite polarity. is there. The voltage adjustment circuit 4C includes a voltage adjustment command circuit 4C-2 and a coil selection circuit 4 similar to the voltage adjustment command circuit 4-2, the coil selection circuit 4-3, and the resistance circuit 4-4.
C-3 and the resistance circuit 4C-4, and the connection state is the same as that described above.

In the circuit shown in FIG. 5, the above equation (1),
In (2) and (3), N ₁ = −N ₁ and Φ ₃₁ = E ₁₁ / E = (− N ₁ + N ₂ + N ₃ + N ₄ ) / (N ₂ + N ₃₎ + N ₄ ) (21) Φ ₃₂ = E ₁₂ / E = (− N ₁ + N ₂ + N ₄ ) / (N ₂ + N ₄ ) (22) Φ ₃₃ = E ₁₃ / E = (− N ₁ + N ₂ ) / ( N ₂ ) The input voltage is boosted by (23). In order to adjust the voltage by 2%, Φ ₃₁ = 0.98 (24) Φ ₃₂ = 0.96 (25) Φ ₃₃ = 0.94 (26). If N ₁ = 10T, N ₂ = 166.7T N ₄ = 83.3T N ₃ = 240T is obtained. The switching coil 2 and the pressure adjusting coil 3 are described above.
Have been described as having the same polarity. For example, a part of the pressure adjusting coil 3 has the same polarity as the main coil 1 and the switching coil 2.
If the remaining part has the opposite polarity, or if the main coil 1 and the pressure adjusting coil 3 have the same polarity and the switching coil 2 has the opposite polarity, the voltage of both the step-up and step-down is selected by selecting the coil. Control becomes possible.

FIG. 6 shows an autotransformer 10A for step-down as described above.
Auto-transformer 10 consisting of a step-up auto-transformer 10C
AC is shown. The main coils 1A and 1C used in the composite transformer 10AC are connected in opposite polarities, but the voltage adjustment circuits 4A and 4C are different in the number of turns of the switching coils 2A and 2C and the number of turns of the pressure adjustment coils 3A and 3C. Except for this, the configuration is the same. Assuming that the first external connection terminals 10-1 and 10-2 are input terminals, the step-down autotransformer 10A is activated when the voltage is too high, and the same when the voltage is too low.
C functions to maintain the output voltages of the second external connection terminals 10-3 and 10-4 within a certain allowable range. At that time, the other circuit is in a through state.

FIG. 7 shows a composite autotransformer 10AD having a different configuration from the above for step-up / step-down. The autotransformer 10A for step-down is similar to that shown in FIG.
The step-up autotransformer 10D is obtained by exchanging the input and output of the transformer 10A. Therefore, the voltage adjustment circuit 4A used in the former
And the 4D used in the latter have the same configuration except for the number of turns of the coil used and the numerical value of the resistance.

FIG. 8 shows an autotransformer 10UV for an AA power supply circuit. In the circuit for AA power circuit,
A voltage adjustment circuit may be provided for each of the U-phase and the V-phase, but in this circuit, the main coil 1U for the U-phase is provided.
And the V-phase main coil 1V are configured to share the voltage adjustment circuit 4UV.

FIG. 9 shows a tapped autotransformer for three-phase AC. In this configuration example, tapped autotransformers 10R, 10S and 10T are respectively connected to the R, S and T phase lines.
Is provided. The transformers 10R, 10S, and 10T can be configured for boosting and for stepping down. Further, a transformer for boosting and a transformer for stepping down can be used in combination. These can be used for star bonding.
Thus, the step-down circuit can be used not only as a stabilized power supply, but also, for example, if the supply voltage is controlled so as to be low at first and then gradually step up.
It can also be used as a motor starter.
Further, a heating device or the like can also be used for applications in which a high voltage is supplied first and then the voltage is gradually reduced.

The configuration of the present invention is not limited to the above-described embodiment. For example, regarding the configuration of the coil, all the coils can be formed as a single tapped coil, and the adjustment can be performed. The pressure coil 3 may also be a plurality of independent coils,
Also, the number of taps and the number of turns can be freely changed within the scope of the object of the present invention, and the switch can also adopt a semiconductor element or various relays. Is included.

[0035]

Since the present invention is constructed as described above, according to the present invention, it is possible to provide a stabilized power supply circuit capable of reliably supplying a predetermined voltage to a load even when there is a wide range of voltage fluctuation. It is. Also, the autotransformer used in the present invention is:
It is extremely simple to manufacture, easy to control quality, inexpensive and can be provided in large quantities.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an outline of an AC stabilized power supply according to the present invention.

FIG. 2 is a circuit diagram showing a configuration example of an autotransformer used in the stabilized AC power supply shown in FIG. 1;

FIG. 3 is a circuit diagram showing a configuration example of an autotransformer using a tapped coil used in the stabilized AC power supply according to the present invention.

FIG. 4 is a circuit diagram showing a configuration example of an autotransformer different from that shown in FIG. 3;

FIG. 5 is a circuit diagram showing a configuration example of an autotransformer different from those shown in FIGS. 3 and 4;

FIG. 6 is a circuit diagram showing a configuration example of an autotransformer used in a step-up / step-down AC stabilized power supply.

FIG. 7 is a circuit diagram showing a configuration example of a step-up / step-down auto-transformer different from that shown in FIG. 6;

FIG. 8 is a circuit diagram showing a configuration example of an autotransformer used in an AC stabilized power supply for single three phase.

FIG. 9 is a circuit diagram showing a configuration example of an autotransformer used in an AC stabilized power supply for three-phase star connection.

[Explanation of symbols]

 1 ... Main coil 2 ... Switching coil 3 ... Pressure adjusting coil 4 ... Voltage adjustment circuit 4-1 ... Voltage adjustment command input terminal 4-2 ... Voltage adjustment command Circuit 21 ... Voltage adjustment command switch 22 ... Switching coil short circuit switch 23 ... Switching coil short circuit 4-3 ... Coil selection circuit 31, 32 ... Coil selection switch 33 ...・ Coil path switch 34 ・ ・ ・ ・ Short circuit 4-4 ・ ・ ・ Resistance circuit 41 ・ ・ ・ ・ Resistance 42 ・ ・ ・ ・ Resistance selection switch 4-5 ・ ・ ・ Input / output common terminal 10 ・ ・ ・ ・ Single winding Transformers 10-1, 10-2 ... First external connection terminal 10-3, 10-4 ... Second external connection terminal 20 ... Voltage detection circuit 30 ... Operation circuit 40 .... Ignition circuit 50 ... Load

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yoshihiko Matsunaga 6-19-7 Hongo, Bunkyo-ku, Tokyo No. 402 Building 402

Claims (10)

[Claims] 1. An AC stabilized power supply comprising the following components A to D: (A) An autotransformer (1) comprising the following components a to d:
0). (a) A pair of first external connection terminals (10-1, 10-2). (b) A pair of second external connection terminals (10-3, 10-4). (c) having an iron core, one terminal (1-1) of which is one of the first external connection terminals (10-1) and the other terminal (1-2) is one of the second external connection terminals Main coil (1) connected to (10-3) and through which load current flows. (d) Voltage adjustment circuit consisting of the following components a or e
(Four). (A) An input terminal (4-1) connected to one of the terminals (1-1, 1-2) of the main coil (1). (B) An input / output common terminal (4-5) to which the other terminal (10-2) of the first external connection terminal is connected to the other terminal (10-4) of the second external connection terminal. (C) Switching coil wound on the same core as the main coil (1)
(2), a voltage adjustment command switch (21) inserted in series between the main coil (1) and the switching coil (2), and a switching coil short-circuit switch (22). Regardless of the state of (21), both terminals of the switching coil (2) (2-1, 2-
2) A voltage adjustment command circuit (4-2) including a switching coil short circuit (23) capable of short-circuiting between them. (D) At least one pressure regulating coil (3) wound around the same core as the main coil (1) and the switching coil (2), a coil selection switch (31, 32), and a coil pass switch (33) A voltage adjustment command circuit that passes through the pressure regulating coil (3) or is appropriately selected from them.
A coil selection circuit (4-3) that can be connected in series with (4-2). (E) A desired resistor (41) and a resistor selection switch (42) are connected in series, connected in parallel with one of the coil selection switches (31, 32), and at least one pressure-adjusting coil.
The resistor circuit (4-4) that forms the circulating current circuit of (3). (B) A circuit (20) for detecting a voltage between the first external connection terminals (10-1, 10-2) or between the second external connection terminals (10-3, 10-4). (C) An arithmetic circuit (30) for generating a switch control signal necessary to maintain an output voltage within a predetermined allowable range according to a detection result of the voltage detection circuit (20). (D) In accordance with a switch control signal generated by the arithmetic circuit (30), each switch built in the autotransformer (10) is controlled to open and close to maintain an output voltage within a certain allowable range ( Four
0). 2. A pressure adjusting coil (3) having a tap (3-1, 3-2, 3
−3), a tap coil wound around the same iron core as the main coil (1) and the switching coil (2), and the coil selection circuit (4A-3) includes taps (3-1, 3). -2, 3-3), the coil selection switch (31, 32) and the coil path switch (33), and their coil selection switches (31, 32).
The stabilized AC power supply according to claim 1, comprising a circuit (34) for short-circuiting a terminal of the coil path switch (33) on a side opposite to a tap of the coil path switch (33). 3. A pair of first external connection terminals (10-1, 10-2) are input voltage terminals, and a pair of second external connection terminals (10-3, 10-
3. The stabilized AC power supply according to claim 1, wherein 4) is an output voltage terminal. 4. A pair of second external connection terminals (10-3, 10-4) are input voltage terminals, and a pair of first external connection terminals (10-1, 10-
3. The stabilized AC power supply according to claim 1, wherein 2) is an output voltage terminal. 5. The AC stabilization method according to claim 1, wherein when an input voltage fluctuates beyond an allowable limit, the input voltage is automatically converted to a voltage within a predetermined allowable range and output. Power supply. 6. A step-up / step-down AC stabilized power supply comprising a step-down AC stabilized power supply and a step-up AC stabilized power supply. 7. An AC stabilized power supply for a single-phase power supply according to claim 1. 8. An AC stabilized power supply for an AA circuit according to any one of claims 1 to 6. 9. An AC stabilized power supply for a three-phase circuit, wherein the AC stabilized power supply according to claim 1 is star-connected. 10. A reduced voltage using an AC stabilized power supply according to claim 9, wherein the output voltage is controlled to be low at first and then to be gradually increased to be usable as a motor starter. Starter.