JP4535763B2 - AC voltage regulator - Google Patents

Description

  The present invention relates to a one-tap AC voltage adjusting device that includes a switch provided in a transformer, and steps down or boosts an input voltage by switching to output.

  As an AC voltage adjusting device connected to a conventional single-phase three-wire line, for example, there is one described in JP 2001-145350 A. In this conventional technique, switching is performed by a plurality of taps, but the adjustment device can be switched by one tap. A conventional example in this case will be described with reference to FIG. Input terminals X and Y are connected to main windings 1 and 2 of the autotransformer, and each main winding 1 and 2 is connected to shunt windings 3 and 4, respectively. Output terminals x and y are provided at each connection point of the road winding. A switch M1 is connected between the shunt windings 3 and 4, and a current-limiting reactor 5 is connected in parallel therewith. Further, switches M2 and M3 for short-circuiting the shunt windings 3 and 4 to each other are connected in parallel with the shunt windings 3 and 4, respectively.

  In the AC voltage regulator having such a configuration, when the switch M1 is closed and the switches M2 and M3 are opened, a stepped-down voltage is produced between the output terminals x and y, while the switch M1 is opened. When M2 and M3 are closed, the input voltage is sent directly between the output terminals x and y. In such switching control of the switches M1, M2, and M3, the measuring device 13 measures the input voltage between the input terminals X and Y, and the control unit 14 measures the level of the measured input voltage. Thus, on / off control of the switch is performed so that the output voltage between the output terminals x and y becomes an appropriate voltage. In addition, a neutral line supplies electric power to a consumer as a single-phase three-wire type | system | group line with the output line connected to the said output terminal x and y.

When switching control is performed to avoid the problem that the switches are closed at the same time and the electric circuit is short-circuited, at a certain moment, all the switches are opened and a high voltage is generated in the windings. The current limiting reactor 5 is provided to prevent this.
JP 2001-145350 A

  A configuration example of the current limiting reactor 5 is as follows. That is, in order to step down the input voltage by 5% when the capacity of the autotransformer is 10 kVA, the number of turns of the main winding is 6T and the shunt winding is 118T.

In this case, the current-limiting reactor 5 has a voltage between the input terminals X and Y of 200 V, so that the rated current is 50 A from the following equation.

10,000 (VA) / 200 (V) = 50 (A)

The current flowing in the 118T shunt winding is 2.5 (A) from the following equation of an equal ampere turn with 6T of the main winding.

6 (T) × 50 (A) / 118 (T) = 2.5 (A)

Since the input voltage 200V is applied to both ends of the current limiting reactor with all the switches open, the capacity is 0.5 (kVA) from the following equation.

200 (V) x 2.5 (A) = 0.5 (kVA)

  FIG. 8 shows an example of the shape in the case where this 0.5 kVA current-limiting reactor is manufactured from a silicon steel plate generally used as a core material. In this figure, the width W is 130 mm, the depth D is 130 mm, the height H is 120 mm, and the weight is about 7 kg.

  Thus, in order to prevent the generation of the high voltage in the current limiting reactor 5 which is a protection circuit, there is a problem that the volume is large, the weight is heavy, and the price is also increased.

  Further, the shunt windings 3 and 4 need to be short-circuited when the switch M1 is opened, but there is a problem that there is a moment when all the switches open as described above, and there is no short-circuit during that time. .

  The present invention has been made in view of the above-mentioned problems of the prior art, and its purpose is to provide a compact and lightweight protection circuit for suppressing high voltage generation, and even when all switches are opened, shunt windings are provided. An object of the present invention is to provide a one-tap AC voltage adjusting device in which a short circuit is maintained.

In order to achieve the above object, the present invention provides an AC voltage regulator for measuring a voltage between input terminals of a single-turn transformer and adjusting a voltage between output terminals with one tap, wherein the single-turn transformer The device includes two input terminals, a first main winding and a shunt winding, and a second main winding and a shunt winding that step down equally from the two input terminals, Two output terminals connected between the main winding and the shunt winding and between the second main winding and the shunt winding, and the first and second shunt windings, A first switch provided therebetween, and second and third switches and an abnormal voltage protection circuit connected in parallel to both ends of each of the first and second shunt windings. The first switch is configured by connecting the a contacts of the first and second electromagnetic contactors in series, and the b contact of the first electromagnetic contactor is used as the second switch. , B contact of the second electromagnetic contactor is used as the third switch, the second is when closing the first switch, the third switch is open and the first on-off reversed The first feature is that the second and third switches are controlled to be closed when the device is opened. Further, instead of the first main winding and the shunt winding that equally step down from the two input terminals, the first main winding and the shunt winding that equally step down from the two output terminals, respectively. The second feature is that the wire and the second main winding and the shunt winding are provided.

  A third feature is that the abnormal voltage protection circuit is composed of one or both of a resistor and a capacitor.

According to the first and second aspects of the invention, since the abnormal voltage protection circuit is connected in parallel with the switch at both ends of each shunt winding, the shunt winding is kept short-circuited even when all the switches are opened. Will be able to. In addition, the surge voltage generated in the output voltage when switching the switch can be greatly suppressed. In addition, it is possible to completely avoid the first switch and the second and third switches from being closed at the same time.

  According to the invention of claim 3, since a series circuit of a capacitor and a resistor is used in place of the current limiting reactor of the conventional circuit, the capacity, weight and price can be reduced to a fraction.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a circuit diagram showing a configuration of an embodiment of a voltage regulator of the present invention.

  This embodiment shows a case where the voltage regulator of the present invention is provided on a three-phase single-wire line, input terminals X and Y are connected to main windings 1 and 2, and the main windings 1 and 2 are shunted. Connected to windings 3 and 4, two switches M11a and M12a are connected in series between shunt windings 3 and 4, and an output terminal is connected to the connection point of main winding 1 and shunt winding 3 An output terminal y is provided at the connection point of x and the main winding 2 and shunt winding 4. Further, a switch M11b and an abnormal voltage protection circuit, for example, a series circuit of a capacitor 6 and a resistor 7 are respectively connected to both ends of the shunt winding 3, and a switch M12b and an abnormal voltage are connected to both ends of the shunt winding 4. Protection circuits, for example, a series circuit of a capacitor 8 and a resistor 9 are connected to each other.

  A measuring unit 13 for measuring an input voltage is connected between the input terminals X and Y, and the measuring unit 13 outputs a signal proportional to the input voltage level to the control unit 14. The control unit 14 performs open / close control of the switches M11 and M12 according to the signal input from the measurement unit 13, and adjusts the output voltage. A power supply unit 15 that supplies a DC power supply voltage of several volts to the measurement unit 13 and the control unit 14 is connected between the input terminals X and Y. The neutral line, together with the output line of this device, supplies power to the consumer as a single-phase three-wire line.

  Here, as shown in FIG. 2, the switch M11a is a contact a of the electromagnetic contactor M11, the switch M11b is a contact b of the electromagnetic contactor M11, and the switch M12a is a contact a of the electromagnetic contactor M12. The switch M12b represents the b contact of the electromagnetic contactor M12. In this embodiment, the two switches M11a and M12a are connected in series, but only one of them may be used. Further, the switch connected between the shunt windings 3 and 4 and the two switches connected in parallel with the shunt windings 3 and 4 may all be configured independently.

  The relationship between each switch and the output voltage will be described. When the switches M11a and M12a are opened and the switches M11b and M12b are closed, direct transmission is performed, the switches M11a and M12a are closed, and the switches M11b and M12b are closed. When opened, it functions as a single transformer. When functioning as an autotransformer, the input voltage between the input terminals X and Y is 5% lower than the input voltage by 6T (turns) of the main winding 1 and 118T of the shunt winding. Is output between the output terminals x and y.

  As described above, by arranging the contact of the electromagnetic contactor, the contact a is opened in the state where the power supply voltage from the power supply unit 15 is not supplied to the measurement unit 13 and the control unit 14 before the installation of the apparatus. It will be sent directly. Further, either directly sending the voltage or reducing the voltage by 5% is performed by the control unit 14 controlling each switch by the output of the measuring unit 13 that measures the input voltage.

  The measurement unit 13 includes a full wave rectifier 131 and a smoother 132. As shown in FIG. 3, the full-wave rectifier 131 receives the input voltage between the input terminals X and Y having the waveform as shown in FIG. Thus, the negative voltage is inverted, and the DC voltage component proportional to the amplitude level of the input voltage as shown in FIG. Here, the smoother 132 can be constituted by, for example, a low-pass filter having a sufficient cutoff characteristic of a commercial frequency.

  The controller 14 includes first and second reference voltage setting units 141 and 146, first and second comparators 142 and 147, first and second counters 144 and 149, and first and second counters. It consists of duration setting units 143 and 148.

  The DC output of the smoother 132 is input to the first and second comparators 142 and 147 of the control unit 14. When the input voltage between the input terminals X and Y (see FIG. 3A) rises, the first comparator 142 sets the first reference voltage setter 141 set in advance to step down the input voltage. Compare with the voltage value set in. If the DC output of the smoother 132 is equal to or higher than the voltage value of the first reference voltage setter 141, a voltage having a truth level “1” is output. The set voltage of the first reference voltage setter 141 here is, for example, 212 V in terms of the effective value of the input voltage.

  Next, the duration of the voltage of truth value 1 of the first comparator 142 is measured by the first counter 144, and when the measured value reaches the set time set in advance in the first duration setter 143, A first switch control signal 16a is output. In accordance with the first switch control signal 16a, the switches M11a and M12a are closed and the switches M11b and M12b are opened. This state is maintained by each switch. As described above, the first switch control performs the step-down control and supplies the customer with the voltage that has been stepped down by 5%.

  On the other hand, the second comparator 147 is set to the second reference voltage setting unit 146 that is set in advance in order to set the apparatus to the direct transmission state when the input voltage between the input terminals X and Y drops. Compare with the measured voltage value. If the DC output of the smoother 132 is less than or equal to the voltage value of the second reference voltage setter 146, a voltage having a truth level “1” is output. The set voltage of the second reference voltage setter 141 here is, for example, 203 V in terms of the effective value of the input voltage.

  Next, the duration of the voltage of the truth value 1 of the second comparator 147 is measured by the second counter 149, and when the measured value reaches the set time preset in the second duration setter 148, A second switch control signal 16b is output. In response to the second switch control signal 16b, the switches M11a and M12a are opened, and the switches M11b and M12b are closed. This state is maintained by each switch. In this way, the second switch control performs direct feed control.

  In the above control, since the switches M11a and M11b and M12a and M12b are constituted by the a and b contacts of the magnetic contactors M11 and M12, respectively, no short circuit occurs, but all switches are open. A state that becomes instantaneously exists, and a high voltage depending on the number of windings is applied to the shunt windings 3 and 4. At this time, since the wire size (the diameter of the winding) of the main winding is larger than that of the shunt winding, the shunt winding is the target of protection.

  In the present embodiment, the capacitor 6 and the resistor 7 are connected to both ends of the shunt winding 3, so that when the high voltage as described above is generated instantaneously, the charging action of the capacitor 6 and the rapid current are suppressed. The generation of the high voltage is suppressed by the action of the current limiting resistor 7. Also, in the shunt winding 4, the capacitor 8 and the resistor 9 are connected to both ends of the shunt winding 4, so that a high voltage is generated by the same action as in the shunt winding 3. It is suppressed. As described above, the circuit composed of the capacitor and the resistor connected to both ends of the shunt windings 3 and 4 is a protection circuit that always protects the shunt winding from a high voltage.

  Here, when the switches M11a and M12a are closed with the capacitors 6 and 8 and the resistors 7 and 9 removed, and the switches M11b and M12b are opened, the output terminals x and y are connected as shown in FIG. The surge voltage p of about 400V was generated in the output voltage of. For this reason, it is expected that problems such as deterioration of the contact of the switch occur due to the opening / closing operation of each switch.

  Next, when the capacitors 6 and 9 and the resistors 7 and 9 are set to have a capacitance of 30 μF and 4Ω at which the surge waveform is minimized, the switches M11a and M12a are turned on with this constant, and the switches M11b and M12b are turned off. The output voltage between the output terminals x and y is shown in FIG. In FIG. 5, the surge voltage p 'is suppressed to about 70V. 4 and 5 are waveforms measured by connecting to an actual three-phase single-wire system.

The sizes of the capacitors 6 and 8 are, for example, a width W of 58 mm, a depth D of 35 mm, and a height H of 50 mm. The resistors 7 and 9 are, for example, a cylinder having a radius of 12 mm and a width W of 53 mm. Since two of these are required, the volume is about 251000 mm ³ . Since the conventional current-limiting reactor 5 is about 2030000 mm ^3, it is greatly downsized. Further, the weight of the current limiting reactor 5 is about 7 kg in the configuration mainly composed of a silicon steel plate, and the weight of the present invention is significantly reduced to 1 kg or less.

  The capacity of the capacitor is 0.71 kVA while the current-limiting reactor being compared is 0.5 kVA. In terms of price, the current-limiting reactor is several thousand yen compared to 10,000 yen or more.

  The voltage regulator for boosting can be configured in FIG. 6 in which the input terminals X and Y and the output terminals x and y of the step-down voltage regulator shown in FIG. 1 are interchanged. In FIG. 6, the same or equivalent parts as those in FIG.

  The operation of FIG. 6 will be described. When the switches M11a and M12a are opened and M11b and M12b are closed, direct transmission is performed. On the other hand, when the switches M11a and M12a are closed and M11b and M12b are opened, the turns ratio of the main winding and the shunt winding ( 6/118), a voltage obtained by boosting the input voltage between the input terminals X and Y by 5% can be output between the output terminals x and y.

  Here, the operation of the control unit 14 will be described. The smoothing device 132 of the measuring unit 13 outputs a DC voltage having a magnitude depending on the input voltage between the input terminals X and Y similar to that described with reference to FIG. The DC output of the smoother 132 is input to the first and second comparators 142 and 147 of the control unit 14. The first comparator 142 compares the input voltage between the input terminals X and Y with a voltage value set in the first reference voltage setting unit 141 set in advance to boost the input voltage. To do. If the DC output of the smoother 132 is less than or equal to the voltage value of the first reference voltage setter 141, a voltage having a truth level “1” is output. The set voltage of the first reference voltage setter 141 here is, for example, 192 V in terms of the effective value of the input voltage.

  Next, the duration of the voltage of truth value 1 of the first comparator 142 is measured by the first counter 144, and when the measured value reaches the set time set in advance in the first duration setter 143, A first switch control signal 16a is output. In accordance with the first switch control signal 16a, the switches M11a and M12a are closed and the switches M11b and M12b are opened. This state is maintained by each switch. As described above, the first switch control performs the boost control and supplies a voltage boosted by 5% to the consumer.

  On the other hand, the second comparator 147 is set to the second reference voltage setting unit 146 that is set in advance in order to set the apparatus to the direct transmission state when the input voltage between the input terminals X and Y rises. Compare with the measured voltage value. If the DC output of the smoother 132 is equal to or higher than the voltage value of the second reference voltage setter 146, a voltage having a truth level “1” is output. The set voltage of the second reference voltage setter 141 here is, for example, 201 V in terms of the effective value of the input voltage.

  Next, the duration of the voltage of the truth value 1 of the second comparator 147 is measured by the second counter 149, and when the measured value reaches the set time preset in the second duration setter 148, A second switch control signal 16b is output. In response to the second switch control signal 16b, the switches M11a and M12a are opened, and the switches M11b and M12b are closed. This state is maintained by each switch. In this way, the second switch control performs direct feed control.

  According to this embodiment, since the a contact and the b contact of the switches M11 and M12 are not closed at the same time, a short circuit of the electric circuit can be easily prevented. In addition, since the contact a is opened in the state where the power supply voltage is not applied, when there is no power supply at the time of installation or when there is a failure, the direct contact state is set and the electric circuit is not affected. Furthermore, since a series circuit of a capacitor 6 and a resistor 7 and a series circuit of a capacitor 8 and a resistor 9 are respectively connected to both ends of the shunt windings 3 and 4, the shunt is even when all switches are opened. Winding short circuit is maintained.

  In the above-described embodiment, the circuit connected to both ends of the shunt windings 3 and 4 has been described as a series circuit of a capacitor and a resistor. However, only one of the capacitor and the resistor or a parallel connection can be considered.

It is a circuit diagram which shows the structure of 1st Embodiment of this invention. It is explanatory drawing of the principal part of the switch which has a contact and b contact. It is a wave form diagram explaining the function of the measurement part of FIG. It is explanatory drawing of the surge voltage in a conventional circuit. It is explanatory drawing of the surge voltage in 1st Embodiment of this invention. It is a circuit diagram which shows the structure of 2nd Embodiment of this invention. It is a circuit diagram of an example of the conventional alternating voltage adjustment circuit. It is a current-limiting reactor front and side view.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1, 2 ... Main winding, 3, 4 ... Shunt winding, M11a, M11b, M12a, M12b ... Switch, 13 ... Measuring part, 14 ... Control part.

Claims (3)

An AC voltage adjustment device that measures the voltage between the input terminals of the autotransformer and adjusts the voltage between the output terminals with one tap,
The autotransformer is
Two input terminals, a first main winding and a shunt winding, and a second main winding and a shunt winding, which are stepped down equally from the two input terminals, and the first main winding Two output terminals connected between the line and the shunt winding and between the second main winding and the shunt winding, and between the first and second shunt windings. The first and second switches, and the second and third switches and the abnormal voltage protection circuit connected in parallel to both ends of the first and second shunt windings,
The first switch is configured by connecting the a contacts of the first and second electromagnetic contactors in series, and the b contact of the first electromagnetic contactor is used as the second switch, The b contact of the second electromagnetic contactor is used as the third switch,
When the first switch is closed, the second and third switches are opened. Conversely, when the first switch is opened, the second and third switches are closed. AC voltage regulator to control. An AC voltage adjustment device that measures the voltage between the input terminals of the autotransformer and adjusts the voltage between the output terminals with one tap,
The autotransformer is
Two output terminals, a first main winding and a shunt winding, and a second main winding and a shunt winding, which are stepped down equally from the two output terminals, and the first main winding Between two input terminals connected between the line and the shunt winding and between the second main winding and the shunt winding, and between the first and second shunt windings. The first and second switches, and the second and third switches and the abnormal voltage protection circuit connected in parallel to both ends of the first and second shunt windings,
The first switch is configured by connecting the a contacts of the first and second electromagnetic contactors in series, and the b contact of the first electromagnetic contactor is used as the second switch, The b contact of the second electromagnetic contactor is used as the third switch,
When the first switch is closed, the second and third switches are opened. Conversely, when the first switch is opened, the second and third switches are closed. AC voltage regulator to control. In the alternating voltage regulator of Claim 1 or 2,
The abnormal voltage protection circuit is composed of one or both of a resistor and a capacitor, and is an AC voltage regulator.

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