JP3040861U - AC stabilized power supply and reduced voltage starter using the same - Google Patents

Abstract

(57) [Problem] To provide an inexpensive and reliable AC stabilized power supply using an autotransformer. SOLUTION: A main coil, a switching coil and a plurality of pressure regulating coils are wound around a common core so that a load current flows through a main coil of an autotransformer, and switching is performed according to an input voltage. A coil and a plurality of pressure regulating coils are selectively connected to the main coil, and a turn ratio is changed and controlled to adjust an output voltage. When the input voltage is within the allowable range, the switching coil and the pressure regulating coil are disconnected from the main coil, and both terminals of the switching coil are short-circuited.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to an AC stabilized power supply for single-phase or multi-phase AC, and particularly to an AC stabilized power supply using a tapped autotransformer.

[0002]

[Prior art]

 Some stabilized AC power supplies have infinitely adjustable voltage, but they are generally expensive. Therefore, a tap-switching transformer in which a tap for voltage adjustment is provided on the primary or secondary winding has been proposed.

However, these tap switching type transformers also require windings on the primary side and the secondary side of the common iron core, which complicates the process and is not necessarily inexpensive, which hinders their popularization. Was there.

[0004]

[Problems to be solved by the device]

 The present invention has been made to solve the above problems, and an object thereof is to provide an inexpensive AC stabilized power supply that uses an autotransformer with a simple winding. is there. Thus, in the conventionally known autotransformer, if an attempt is made to automatically select or switch the combination of the coil or its taps in accordance with the input voltage, accidents such as burning of the coil or abnormal voltage will occur. We could not construct an AC stabilized power supply that requires automatic switching. The gist of the present invention is a novel autotransformer having a plurality of coils and a control circuit capable of safely and automatically selecting or switching a combination of coils or taps according to an input voltage. It is to provide an AC stabilized power supply.

[0005]

[Means for Solving the Problems] The above object is to provide a main coil and a switching coil, and at least one, preferably a plurality of pressure adjusting coils, on a common iron core as a transformer for voltage adjustment. Connect one terminal of the coil to one of the input lines and the other terminal to one of the output lines, and connect the other one of the input lines and the other one of the output lines to the common input / output. It is equipped with a connection terminal, and further comprises a changeover coil, a voltage adjustment command switch inserted in series between the changeover coil and the main coil, and a changeover coil short-circuit switch. Regardless of the voltage adjustment command circuit consisting of a switching coil short-circuit circuit that can short-circuit both terminals of the switching coil, and a coil selection switch, the one that is selected from the pressure adjustment coils at any time is adjusted in voltage. The voltage adjustment command circuit and the coil selection circuit are connected in series between the coil selection circuit connected in series with the control circuit and one of the terminals of the main coil and the common input / output connection terminal. An autotransformer consisting of a resistor circuit consisting of a desired resistor and a resistance selection switch connected in series with one of the coil selection switches in parallel is used, and the input or output voltage of the autotransformer is used. Is detected, the switches provided in the above circuits are controlled to open and close according to the detection result, and the output voltage is maintained constant within a predetermined allowable range by an AC stabilized power supply.

Therefore, the feature of the present invention is that even if the autotransformer is used, the voltage adjustment command switch, the switching coil short-circuit switch, and the resistance selection switch are appropriately controlled to be opened and closed safely. The purpose is to enable smooth selection and switching of the voltage adjustment coil. The AC stabilized power supply according to the present invention can be configured not only for single phase but also for three-phase or more multi-phase, and for step-down voltage used when the input voltage is higher than the allowable range, It can be provided as an AC stabilized power supply for boosting and for both step-up and step-down voltage used in the opposite case, and since it is possible to control the sequence of the output voltage significantly, it can be used for motor starters, heating devices, etc. It can be used for sequence control of supply voltage.

[0007]

[Embodiment of the invention]

 Hereinafter, the present invention will be described in detail 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, and FIG. 2 is a circuit diagram showing one configuration example of an autotransformer used in the AC stabilized power supply shown in FIG. 3 is a circuit diagram showing an example of the configuration of an autotransformer using a coil with a tap used in the AC stabilized power supply according to the present invention, and FIG. 4 is a single winding different from that shown in FIG. FIG. 5 is a circuit diagram showing a configuration example of a transformer, FIG. 5 is a circuit diagram showing a configuration example of an autotransformer which is different from those shown in FIGS. 3 and 4, and FIG. Circuit diagram showing an example of the configuration of an autotransformer used in a dual-purpose AC stabilized power supply. Fig. 7 shows an example of the configuration of an autotransformer for both buck-boost different from the one shown in Fig. 6. 8 is a circuit diagram showing a configuration example of an autotransformer used in an AC stabilized power supply for AA, and FIG. 9 is a three-phase star connection. An example of the configuration of the autotransformer to be used in an AC stabilized power supply use is a circuit diagram showing an.

[0008]

【Example】

 Hereinafter, description will be sequentially given from FIG. FIG. 1 shows the basic configuration of a stabilized power supply for single-phase alternating current using a tapped autotransformer according to the present invention. In FIG. 1, reference numeral 10 denotes an autotransformer, which includes a main coil 1, a switching coil 2, a pressure adjusting coil 3 and a voltage adjusting circuit 4 wound around a common iron core (not shown).

Further, 20 is a voltage detection circuit for detecting the output voltage of the autotransformer 10, and 30 is a control necessary for keeping the output voltage within a predetermined allowable range according to the detection result of the voltage detection circuit 20. An arithmetic circuit 40 that generates a signal is an ignition circuit 40 that controls the opening and closing of each switch provided in the voltage adjusting circuit 4 according to the control signal of the arithmetic circuit 30 to maintain the output voltage within a certain allowable range. , 50 are load circuits.

In this embodiment, the first external connection terminals 10-1 and 10-2 are on the power supply side, and the second external connection terminals 10-3 and 10-4 are on the load side. , This autotransformer 10 is reversible, and it is also possible to use the first external connection terminals 10-1 and 10-2 as the load side and the second external connection terminals 10 -3 and 10-4 as the power supply side. Is. However, in that case, if the state shown in the figure is for step-down, it will be for step-up when the input and output are reversed.

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 with the same polarity. As will be described later, the number of turns of the main coil 1 is extremely smaller than that of the switching coil 2 and the pressure adjusting coil 3. The autotransformer 10 is a four-terminal network circuit, each having a pair of first external connection terminals 10-1, 10-2 and second external connection terminals 10-3, 10-4, respectively, in this embodiment. In this case, 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 are connected to the 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 1-2 is connected to one of the second external connection terminals 10-3. Then, a load current is passed through the main coil 1. The voltage adjustment command input terminal 4-1 of the voltage adjustment circuit 4 including the switching coil 2 and the pressure adjustment coil 3 is connected to the output side line connected to the other terminal 1-2 of the main coil 1 described above, and the input / output is common. The other one of the first external connection terminal 10-2 and the second external connection terminal 10-4 is connected to the terminal 4-5.

The output voltage to the load 50 is detected by the voltage detection circuit 20, the detection data is sent to the calculation circuit 30, and the calculation circuit 30 uses the data to output the voltage adjustment circuit via the ignition circuit 40. Each of the switching elements built in 4 is controlled to open and close to keep the input voltage to the load 50 within a predetermined allowable range. If the voltage of the first external connection terminals 10-1 and 10-2 is normal and the voltage between the second external connection terminals 10-3 and 10-4 is within the allowable range without voltage adjustment, As shown in 1, the voltage adjustment command switch 21 is turned off, the voltage adjustment circuit 4 is disconnected from the power supply line to the load 50, and the autotransformer 10 is used as a transformer. It is not functioning and is in the so-called through state.

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 consumes 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 almost entirely supplied to the load 50. Thus, if the voltage supplied between the first external connection terminals 10-1 and 10-2 becomes a high voltage above a certain allowable limit, the voltage supplied to the load 50 will also exceed the allowable range and become high. , 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 acts as an autotransformer, and the voltage of the second external connection terminals 10-3 and 10-4 is desired. Automatically adjust to keep within the allowable range of.

A simplest configuration example of the voltage adjusting circuit 4 is shown in FIG. 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 becomes higher than the allowable range, it is stepped down to a voltage within the allowable range. Shall be supplied. In the illustrated example, the voltage adjustment circuit 4 is composed of a voltage adjustment command circuit 4-2, a coil selection circuit 4-3, and a resistance circuit 4-4, and these circuits are as shown in the drawing. Further, it 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 and inserted between the voltage adjustment command input terminal 4-1 and the input / output common terminal 4-5, and the resistance circuit 4-4. Are connected in parallel with the coil selection switch 31.

The voltage adjustment command circuit 4-2 includes a switching coil 2, a voltage adjustment command switch 21, and a switching coil short circuit 23 including a switching coil short-circuit switch 22, and the voltage adjustment command switch 21 includes The control coil short-circuit switch 22 provided between the main coil 1 and the switching coil 2 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 voltage adjustment command circuit 4-2 described above, and is provided with one voltage adjustment coil 3 for voltage adjustment, a coil selection switch 31 and a coil path switch 32. It is for selecting whether to connect the pressure adjusting coil 3 to the main coil 1 and the switching coil 2. The resistance circuit 4-4 is formed by connecting a resistance 41 and a resistance selection switch 42 in series, and is connected in parallel with the coil selection switch 31.

When the voltage of the first external connection terminals 10-1 and 10-2 is normal and the voltage between the second external connection terminals 10-3 and 10-4 is within the allowable range without voltage adjustment As shown in FIG. 2, all the switches except the changeover coil short-circuit switch 22, that is, the voltage adjustment command switch 21, the coil selection switches 31 and 32, and the resistance selection switch 42 are not turned off. Therefore, only the switching coil short-circuit switch 22 is turned on. As described above, in this state, the voltage regulator 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 the through state, that is, the input state. The voltage is almost output as it is.

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 consumes more energy than its iron loss. Since the impedance of the main coil 1 is extremely small compared to that of the load 50, the voltage of the first external connection terminals 10-1 and 10-2 is almost supplied to the load 50 as it is. Therefore, 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 will also exceed the allowable range, so that the arithmetic circuit 30 The ignition circuit 40 is activated by the signal of, and the switch of the voltage adjusting circuit 4 is switched according to the following procedure, the power supply circuit operates as an autotransformer, and the second external connection terminals 10-3, 10 -4 voltage is reduced.

At this time, the voltage adjustment command switch 21 is turned on and the changeover coil short-circuit switch 22 is turned off. Prior to the changeover of those switches, first, the resistance selection switch 42 and the coil pass switch 33 are turned on. Turn on and insert the resistor 41 in series in the coil circuit. In this state, first turn off the changeover coil short-circuit switch 22, then turn on the voltage adjustment command switch 21, and then set the pressure adjustment coil 3 to the changeover coil. When using it by connecting it to 2, the coil selection switch 31 is turned on and the coil pass switch 33 is turned off. When the pressure regulating coil 3 is disconnected, the coil selection switch 31 is turned off and the coil pass switch 33 is turned on. After the switching of these switches is completed, the resistance selection switch 42 is turned off. Therefore, it is desirable to switch these series of switches at the zero cross point of the current.

The reason why the switching coil short-circuit switch 22 is turned off before turning on the voltage adjustment command switch 21 is that when the voltage adjustment command switch 21 is turned on while the switching coil short-circuit switch 22 is on, the switching This is because an excessive current flows through the coil 2 and the switching coil 2 burns in an instant, so that such a situation is avoided. Further, the reason why the coil pass switch 33 is turned on and the resistor 41 is inserted in the circulating current circuit of the pressure adjusting coil 3 is to prevent the iron core from being saturated and causing an abnormal voltage to occur in each coil. That is, when the resistor 41 is inserted in series with the coil circuit, the circuit becomes like a current transformer having a load resistor, and when the voltage adjustment command switch 21 is turned on, the resistor 41 is It becomes the current limiting resistance of the closed circuit including the coil pass switch 33, and the occurrence of abnormal voltage due to oversaturation of the iron core is prevented. The insertion of the resistor 41 into the coil circuit is always performed in advance when the coil selection switch 31 and the coil pass switch 33 are switched again or when the voltage adjustment command switch 21 is turned off. In this case, the purpose of connecting the resistor 41 is to limit the short-circuit current when the coil selection switch 31 and the coil pass 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 thereof is sent to the arithmetic circuit 30. When the voltage supplied to the load 50 becomes excessive, the arithmetic circuit 30 determines how to select and switch the coil based on the current on / off status of each switch and the voltage detection data, and A command pulse is sent to the arc circuit 40, the coil selection switch 31, the coil path switch 33, and the switching coil short-circuit switch 22 are switched to change the turn ratio of the autotransformer 10 to control the output voltage. . Since the switching of this switch is performed by the procedure described above, the switching of the switch is smoothly performed without the occurrence of overcurrent or abnormal high voltage in each coil, and The voltage supplied to 50 is always kept within a certain tolerance. In the above, in order to explain the principle of the present invention, an example in which a single coil is used as the pressure adjusting coil 3 has been shown, but in reality, a plurality of coils are used, and the number of turns and the combination of polarities are used. By making appropriate selections, an AC stabilized power supply is constructed for boosting when the supply voltage drops, for stepping down when used in the opposite case and for both step-up and step-down.

Therefore, in the preferred embodiment of the present invention, it is recommended to use a tapped coil as the voltage adjusting coil 3 because the control circuit is simple. Thus, in FIG. 3, such an autotransformer 10A is shown. 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, the voltage adjustment instruction circuit 4-2, and the voltage adjustment instruction circuit 4-2 shown in FIG. It is similar to the resistance circuit 4-4. A coil with taps is used as the pressure adjusting coil 3 in the coil selection circuit 4A-3. This tapped coil has taps 3-1, 3-2 and 3-3, and these taps 3-1, 3-2 and 3-3 have switches 31 and 32 for coil selection and coil passes. The switches 33 are connected, and the contacts of the switches on the opposite side of the pressure adjusting coil 3 are short-circuited by the short circuit 34 and are 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 in the 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 the same.ゝ It is supplied to load 50. When the voltage supplied to the load 50 exceeds the allowable limit, the voltage adjustment command switch 21 is turned on and the changeover coil short-circuit switch 22 is turned off. First, the resistance selection switch 42 and the coil selection switch 32 or 33 are turned on, and the resistance 41 is inserted in series in the circulating current circuit of the pressure adjusting coil 3. Then, 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 part of the coil with taps used as the pressure adjusting coil 3 is connected to the switching coil 2 and used, the coil selection switches 31, 32 and the coil pass switch 33 are appropriately turned on. The resistance selection switch 42 is turned off after the switch is turned off and the switching of these switches is completed. Now, regarding the number of turns of each coil, N ₁ switching coil 2 between main coil 1 terminals 1-1 and 1-2, N ₂ pressure adjusting coil 3 between terminals 2 and 2-2, tap 3-1, 3-2 The voltage supplied between the N _{3 first} taps 3-2 and 3-3 between the N ₄ first external connection terminals 10-1 and 10-2 is E ₁₁ , E ₁₂ or E ₁₃ , where E ₁₁ <E ₁₂ <E _{13 When} the voltage output between the second external connection terminals 10-3 and 10-4 is E, the transformation ratios Φ ₃₁ , Φ corresponding to the selected coil selection switches 31, 32, 33. ₃₂ and Φ 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 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 regulation coil 3 is disconnected, The winding of the main coil 1, the winding of the switching coil 2, and the winding between the taps 3-2 and 3-3 of the pressure regulating 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 adjustment coil 3 is disconnected, and winding of the coil 1, and the winding switching coil 2 is in series, the input voltage is divided by the winding of the two coils, [Phi _{33 E 13 / E = (N 1} + N 2) / (N 2) (3)

Now, to adjust the voltage by 2%, that is, Φ ₃₁ = 1 / 0.98 E = 0.98E ₁₁ (4) Φ ₃₂ = 1 / 0.96 E = 0.96E ₁₂ (5) Φ ₃₃ = 1 / to a 0.94 E = 0.94E ₁₃ (6), when the N ₁ = 10T, the equation (3) and (6), N ₂ = 156.7T equation (2) and (5), N ₄ = 83.3T From equations (2) and (5), N ₃ = 240T is obtained. According to this structure, even when the input voltage fluctuates between 100 and 108 V, the voltage fluctuation of the output voltage E can be kept within 0 to 2%.

The circuit configuration of the voltage adjusting circuit 4 is not limited to that shown in FIG. 3, and can be modified as shown in FIG. 4, for example. The main coil 1, the switching coil 2 and the voltage adjusting coil 3 used in the autotransformer 10B shown in FIG. 4 are the same as those described above, but the voltage adjusting circuit 4B is the same as the voltage adjusting circuit 4A. Have different circuit configurations.

That is, the voltage adjusting circuit 4B is similar to the voltage adjusting command circuit 4A-2, the coil selecting circuit 4A-3, and the resistor circuit 4A-4, and the voltage adjusting command circuit 4B-2 and the coil selecting circuit are the same. It is composed of a circuit 4B-3 and a resistance circuit 4B-4, but the connection state thereof is changed. However, it will be apparent from the above description that the voltage adjusting circuit 4B functions in the same manner as the voltage adjusting circuit 4 described above, and therefore the description thereof will be omitted here. In short, in the autotransformer according to the present invention, the coil having a small number of turns is the main coil, and one switching coil and a plurality of pressure adjusting coils are wound around the same iron core as the main coil, and the switching coil is the main coil. It is possible to switch between a state in which both terminals are short-circuited and both terminals are short-circuited, and a state in which both terminals are opened and the main coil 1 is connected in series, and at the same time each coil is selected according to the supply voltage. The main core is constructed so that it can be connected in series, and a resistor can be optionally inserted into the circulating current circuit of one of these pressure adjusting coils at any time to prevent the iron core from becoming oversaturated when the switch is switched. In addition, the main coil excitation current is supplied to the load, and the main coil and the coil connected in series increase or decrease the input voltage to keep the output voltage to the load within a certain allowable range. It is intended to maintain.

In the above description, the autotransformer 10 is of the step-down type, but the input and output of the circuits shown in FIGS. 3 and 4 are connected in reverse, and the second external connection terminal 10- It will be immediately understood that it is possible to use it as a step-up type by connecting 3, 10-4 to the power supply as the input terminals and connecting the first external connection terminals 10-1, 10-2 as the output terminals to the load 50. . In this case, Φ ₃₁ = E ₁₁ / E = (N ₂ + N ₃ + N ₄ ) / (N ₁ + N ₂ + N ₃ + N ₄ ) instead of equations (1), (2), and (3) described above. (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, if the voltage is adjusted by jumping by 2%, then 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 this autotransformer 10C, a voltage adjusting circuit 4C having the same configuration as the voltage adjusting circuit 4 described above is used. The autotransformer 10C differs from the autotransformer 10 shown in FIG. 3 in that the main coil 1C is connected to the switching coil 2C and the pressure adjusting coil 3C in the opposite polarity. is there. This voltage adjustment circuit 4C is similar to the voltage adjustment command circuit 4-2, the coil selection circuit 4-3 and the resistance circuit 4-4 described above, and is similar to the voltage adjustment command circuit 4C-2, the coil selection circuit 4C-3 and the resistance circuit. 4C-4 and its connection state is the same as that described above.

In the circuit shown in FIG. 5, in the above equations (1), (2) and (3), N ₁ = −N ₁ is set, and the obtained equation is 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) The input voltage is boosted by Φ ₃₃ = E ₁₃ / E = (-N ₁ + N ₂ ) / (N ₂ ) (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. In the above description, all of the switching coil 2 and the pressure adjusting coil 3 have the same polarity. However, for example, a part of the pressure adjusting coil 3 has the same polarity as the main coil 1 and the switching coil 2, and the remaining part has the same polarity. If the polarities are opposite to these, 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, voltage control for both step-up and step-down is possible by selecting the coil. Becomes

FIG. 6 shows a composite autotransformer 10AC including the autotransformer 10A for step-down and the autotransformer 10C for boosting described above. Although the main coils 1A and 1C used in this composite transformer 10AC are connected to each other in opposite polarities, the voltage adjusting circuits 4A and 4C have switching coils 2A and 2C, pressure adjusting coils 3A and 3C, etc. The configuration is the same except for. If 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 conversely, when the voltage is too low, the 10C functions. , Maintain the output voltage of the second external connection terminals 10-3, 10-4 within a certain allowable range. At that time, the other circuit is in the through state.

FIG. 7 shows a composite autotransformer 10AD having a different structure from the above for buck-boost. The step-down autotransformer 10A is the same as that shown in FIG. 3, and the step-up autotransformer 10D is obtained by replacing the input and output of the step-up autotransformer 10A. Therefore, the voltage adjusting circuit 4A used in the former and the voltage adjusting circuit 4D used in the latter have the same configuration except the number of turns of the coil used and the numerical values of the resistance.

Shown in FIG. 8 is an autotransformer 10UV for an AA power circuit. In the circuit for the AA power supply circuit, voltage adjusting circuits may be provided respectively for the U phase and the V phase, but in this circuit, the main coil 1U for the U phase and the main coil for the V phase are provided. 1V is configured to share the voltage adjusting circuit 4UV.

FIG. 9 shows a tapped autotransformer for three-phase alternating current. In this configuration example, tapped autotransformers 10R, 10S and 10T are provided on the R, S and T phase lines, respectively. The transformers 10R, 10S and 10T may be configured for step-up or step-down, and it is also possible to use a combination of step-up and step-down. These can be used for star coupling. Thus, the step-down circuit is used not only as a stabilized power source, but also as a motor starter, for example, if the supply voltage is controlled to be low at the beginning and gradually increased. It is also possible. In addition, a heating device or the like can also be used for the purpose of supplying a high voltage first and then gradually lowering the voltage.

The structure of the present invention is not limited to the above-described embodiment. For example, regarding the structure of the coils, all the coils can be a single tapped coil, and the coils can be adjusted. The pressure coil 3 may also be a plurality of independent coils, and the number of taps and the number of turns of the coil can be freely changed within the scope of the object of the present invention, and the switch adopts a semiconductor element or various relays. It is possible that the present invention covers all of these modifications.

[0035]

[Effect of the invention]

 Since the present invention is constructed as described above, the present invention can provide a stabilized power supply circuit that can reliably supply a predetermined voltage to a load even when there is a wide range of voltage fluctuations. Further, the autotransformer used in the present invention is extremely simple to manufacture, has easy quality control, and can be provided in large quantities at low cost.

[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 coil with taps used in an AC stabilized 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

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Yoshihiko Matsunaga 6-19-7 Hongo, Bunkyo-ku, Tokyo Yushasha Building No. 402

Claims (10)

[Utility model registration 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.