JP3391104B2 - Automatic voltage regulator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic voltage regulator for adjusting a power supply voltage.

[0002]

2. Description of the Related Art Conventionally, there has been an automatic voltage regulator that automatically controls an inductive voltage regulator to regulate the voltage at the load end.
Fig. 5 shows the overall system diagram of the automatic voltage regulator.
In FIG. 5, U and V are input terminals, u2 and v2 are output terminals, V1 is an input voltage, V2 is an output voltage, 50 is an induction type voltage regulator, and this induction type voltage regulator 50 has a slot in an iron core. The primary winding 51a is wound around the rotor, and the secondary winding 51b is wound around the same stator to change the coupling relationship between both windings to change the output voltage. The output voltage V2 of the induction type voltage regulator 50 is represented by V2 = V1 + V21 cos θ. Here, V21cos θ is the voltage generated between the stator windings for the voltage compensation, and θ is the rotation angle of the rotor. Therefore, the output voltage V2 is changed from the maximum value V1 + V21 to the minimum value V1− by changing the rotation angle θ from 0 to π radians.
It is configured so that it can be changed up to V21. Reference numeral 52 is a voltage detection unit for detecting the output voltage V2, 53 is a control unit, and the control unit 53 compares the voltage value detected by the voltage detection unit 52 with a predetermined reference voltage to calculate a deviation and further Angle detector 56 mechanically coupled to the rotor of
The control command is output in comparison with the output value of. 5
Reference numeral 4 denotes a motor control unit that drives and controls the motor 55 based on the control command output by the control unit 53.

The operation of the automatic voltage regulator configured as described above will be described with reference to FIG. Now the input voltage V1 is U
When it is applied between the −V terminals, an output voltage V2 is generated, the voltage detection unit 52 detects the output voltage V2, and compares it with a reference voltage predetermined by the control unit 53. Furthermore, the control unit 5
At 3, the deviation between the reference voltage and the output voltage V2 is obtained, and the rotation angle θ is calculated according to this deviation. The calculation result is compared with the output of the rotation angle detector 56, and a command according to the motor rotation angle is given to the motor control unit 54 to drive the motor 55. Further, the rotation angle detector 56 detects the rotation angle θ and feedback control is performed to the control unit 53.

[0004]

As described above, the output voltage V2 of the automatic voltage regulator 50 is adjusted by the motor 5 as described above.
5, the rotation angle θ of the rotor is changed from 0 to π radians to control it to a predetermined voltage. However, the output voltage V
Since a rotating mechanism such as a motor 55 is required to control the motor 2, the structure is complicated and expensive. Further, as a kind of conventional automatic voltage regulator, Japanese Patent Laid-Open No. 206013/1985.
There is also a semiconductor type tap changer disclosed in the publication. However, the control at the time of tap switching is complicated because there are restrictions such as that the control angle of the thyristor must be increased in order to reduce the bridge crossover current at the time of tap switching.

An object of the present invention is to provide a simple automatic voltage regulator which does not require a rotating mechanism.

[0006]

SUMMARY OF THE INVENTION An automatic voltage regulator according to a first aspect of the present invention includes a polarity switching means for switching the polarity of a power supply voltage, and a primary side winding for the power source via the polarity switching means. A transformer that is connected and that connects one end of the secondary winding to one end of the power supply and uses the secondary winding as part of the load voltage, and voltage detection that detects the voltage of the power supply or the load. Means and a comparing means for comparing the voltage value detected by the voltage detecting means with a predetermined reference voltage value, and when the detected voltage of the voltage detecting means is higher than the predetermined first reference voltage value, A voltage is applied to the primary winding of the transformer by the polarity switching means so that the voltage of the secondary winding of the transformer is subtracted from the power supply voltage, and the detection voltage of the voltage detecting means is predetermined. Lower than the second reference voltage value In this case, the control means for applying a voltage to the primary winding of the transformer by the polarity switching means so that the secondary voltage of the transformer is added to the power supply voltage. is there.

In the automatic voltage regulator according to the second aspect of the present invention, the polarity switching means for switching the polarity of the power supply voltage, the primary side winding connected to the power source via the polarity switching means, and A transformer in which one end of a secondary winding is connected to one end of the power source and the secondary winding is used as a part of load voltage,
The power supply or the load is provided with voltage detection means for detecting the voltage, and the comparison means for comparing the voltage value detected by the voltage detection means with a predetermined reference voltage value, and the detection voltage of the voltage detection means is predetermined. When the voltage is higher than the reference voltage value, the voltage is applied to the primary winding of the transformer by the polarity switching means so that the voltage of the secondary winding of the transformer is subtracted from the power supply voltage. When the detected voltage of the voltage detection means is lower than a predetermined reference voltage value, the polarity switching means applies a voltage to the primary winding of the transformer so that the secondary voltage of the transformer is added to the power supply voltage. And a control means for applying a voltage.

The automatic voltage regulator according to the third aspect of the present invention comprises switching means for opening and closing the primary winding of the transformer when the voltage detected by the voltage detecting means is within a predetermined range. It is characterized by.

In the automatic voltage regulator according to the fourth aspect of the invention, the transformer has two secondary windings, one end of the first secondary winding is connected to one end of the power supply, and the other end of the power supply is connected to the other end. One end of the second secondary winding is connected to the first secondary winding and the second secondary winding.
The secondary winding is used as a part of the load voltage.

An automatic voltage regulator according to a fifth aspect of the invention is characterized in that the polarity switching means can switch the polarity of the power source voltage and the phase of the voltage of the power source is controlled.

An automatic voltage regulator according to a sixth aspect of the present invention is characterized in that the polarity switching means is capable of switching the polarity of the power supply voltage and comprises an inverter that variably controls the voltage of the power supply.

An automatic voltage regulator according to a seventh aspect of the present invention comprises an inverter including a forward conversion unit and an inverse conversion unit, and the forward conversion unit is a full wave bridge having no smoothing capacitor. is there.

[0013]

According to the automatic voltage regulator of the first invention, the polarity switching means can switch the voltage phase of the power source, the voltage detecting means detects the voltage of the power source or the load, and the comparing means detects the detected voltage. The value is compared with a predetermined reference voltage value, and the control means subtracts the voltage of the secondary winding of the transformer from the power supply voltage when the detected voltage is higher than the predetermined first reference voltage value. When a voltage is applied to the primary winding of the transformer by polarity switching so that the detected voltage is lower than a predetermined second reference voltage value, the secondary voltage of the transformer is different from the power supply voltage. The voltage is applied to the primary winding of the transformer by polarity switching so that the voltage is added.

According to the automatic voltage regulator of the second invention, the polarity switching means makes it possible to switch the voltage phase of the power source, the voltage detecting means detects the voltage of the power source or the load, and the comparing means detects the detected voltage. Compare the value with a predetermined reference voltage value,
When the detected voltage is higher than a predetermined reference voltage value, the control means changes the polarity of the primary winding of the transformer so that the voltage of the secondary winding of the transformer is subtracted from the power supply voltage. When the detected voltage is lower than a predetermined reference voltage value, the voltage is applied to the primary winding of the transformer by polarity switching so that the secondary voltage of the transformer is added to the power supply voltage. It is applied.

According to the automatic voltage regulator of the third invention, the switching means closes the primary winding of the transformer when the power supply voltage is within a predetermined range.

According to the automatic voltage regulator of the fourth invention, each load is utilized by using the first secondary winding and the second secondary winding of the transformer as a part of the voltage of each load. Voltage compensation independently.

According to the automatic voltage regulator of the fifth aspect of the present invention, the voltage phase of the power source can be switched, and the voltage of the power source is phase-controlled and continuously applied to the primary winding of the transformer. Adjust the voltage.

According to the automatic voltage regulator of the sixth invention, the polarity of the power supply voltage can be switched by the inverter and the power supply voltage is variably controlled.

According to the automatic voltage regulator of the seventh invention, the forward converter of the inverter generates a pulsating voltage and the inverse converter of the inverter uses the pulsating voltage to generate an AC voltage.

[0020]

【Example】

Example 1. FIG. 1 is an overall connection diagram showing an automatic voltage regulator of the present invention. In FIG. 1, reference numeral 1 is a main transformer that generates a power supply voltage. The main transformer 1 has primary terminals U and V and a secondary terminal u.
v and. Wires 1a, 1b, and 1c are wires 1
a and 1b connect between terminals u and u1 and between terminals v and v1, respectively, and the electric wire 1c is connected to the terminal N from the center of the secondary winding of the main transformer 1. 2 is a compensation transformer, and the two secondary windings of the compensation transformer 2 are between terminals u1 and u2, and v1
It is connected between -v2. The polarity of the compensating transformer 2 is such that when the output voltage of the main transformer 1, that is, the voltage having the same phase as the power supply voltage is applied, the voltage having the same phase is generated on the secondary side as well. The side rated voltage is eV. 3a to 3d are phase switching means, and the phase switching means 3a to
Reference numeral 3d is a bidirectional control rectifying element that is turned on and off electrically according to a command signal.
And the bidirectional control rectifying elements 3b and 3d are connected in series one by one. Further, the bidirectional control rectifying element 3a,
One end of 3b is connected to the terminal u1, and one ends of the bidirectional control rectifiers 3c and 3d are connected to the terminal v1.

A set of bidirectional controlled rectifying elements 3 in series
a and 3c and bidirectional control rectifiers 3b and 3d are connected to one end and the other end of the primary winding of the compensating transformer 2 from the respective center points. Therefore, when the bidirectional control rectifying elements 3a and 3d are turned on, a voltage having the same polarity as the output voltage of the main transformer 1 is applied to the primary winding of the compensation transformer 2. In addition,
The bidirectional control rectifying elements 3b and 3c are off. When the bidirectional control rectifying elements 3b and 3c are turned on, a voltage having a phase difference of 180 ° from the output voltage power supply of the main transformer 1 is applied to the primary winding of the compensation transformer 2. The bidirectional control rectifying elements 3a and 3d are off. Reference numeral 3e is an opening / closing means, and this opening / closing means 3e is composed of a bidirectional control rectifying element that is turned on and off electrically based on a command signal, and both ends of the bidirectional control rectifying element 3e are connected between the primary windings of the compensation transformer 2. Has been done. An on / off control unit 4 is connected between the terminals u1 and v1 and detects the voltage between the terminals to control the bidirectional control rectifying elements 3a to 3e on and off. Is. A first load (not shown) is connected between terminals u2 and v2, and a second load and a third load (not shown) are connected between terminals u2 and N and between terminals v2 and N, respectively. It is connected. Therefore, about half of the voltage applied to the first load is applied to the second load and the third load.

Next, the structure of the on / off controller will be described with reference to FIG. In FIG. 2, reference numeral 11 is a transformer for insulation. The transformer 11 has a primary winding connected between terminals u1 and v1, and a secondary winding connected to the input of the full-wave rectification circuit 12. A capacitor 13 is connected to the output of the full-wave rectifier circuit 12, and a resistor 14 and a resistor 15 are connected in series.
Of the resistor 15 and the other end of the resistor 15 is grounded. Therefore, the voltage between the terminals u1 and v1 is transformed, and the detection voltage Vp is generated across the resistor 15. The resistor 14 and the resistor 15 are connected in series to the one of the inputs of the comparators 17a and 17b through the resistors 16a and 16b, respectively. The resistor 18a and the resistor 19a are connected in series, and the connecting portion is connected to the other input of the comparator 17a. One end of the resistor 19a is grounded, and one end of the resistor 18a is connected to a positive power source. Therefore, the reference voltage Vr1 is obtained across the resistor 19a. The reference voltage Vr1 is the first reference voltage Vr1 that serves as a reference for turning on the bidirectionally controlled rectifying elements 3b and 3c when the voltage between the line terminals u1 and v1 rises. The resistor 18b and the resistor 19b are connected in series, and the connection portion is connected to the other input of the comparator 17b. One end of the resistor 19b is grounded, and one end of the resistor 18b is connected to the positive power source. Therefore, the reference voltage Vr2 is obtained across the resistor 19b. The reference voltage Vr2 is a second reference voltage Vr2 that serves as a reference for turning on the bidirectionally controlled rectifying elements 3a and 3d when the voltage between the terminals u1 and v1 drops. Here, the first reference voltage Vr1 and the second reference voltage Vr1
There is a relationship of Vr1> Vr2 with the reference voltage Vr2.

The output of the comparator 17a is supplied to the input of the photocoupler 31b via the resistor 25a. The input sides of the photocoupler 31b and the photocoupler 31c are connected in series, one end of the input of the photocoupler 31c is grounded, and the outputs of the photocouplers 31b and 31c are the control rectification unit 33 including the bidirectional control rectification elements 3b and 3c, respectively.
It is connected to the inputs of b and 33c. Comparator 17
The output of b is supplied to the base of the transistor 28 via the knot gate 22b and the resistor 25b. The collector of the transistor 28 is connected to one end of the input of the photocoupler 31d, and the input sides of the photocouplers 31a and 31d are connected in series and connected to the positive power source via the resistor 29. The outputs of the photocouplers 31a and 31d are connected to the inputs of control rectification units 33a and 33d, which incorporate bidirectional control rectification elements 3a and 3d, respectively. Further, the output of the comparator 17b is an AND gate 26 for obtaining a logical sum.
Of the AND gate 26a and the output of the comparator 17a is supplied to the other input of the AND gate 26 via the NOT gate 22a. The output of the AND gate 26 is a resistor 27.
Is supplied to the input of the photocoupler 31e via. or,
One end of the input of the photocoupler 31e is grounded, and the output of the photocoupler 31e is connected to the input of the control rectification unit 33e including the bidirectional control rectification element 3e.

Reference numeral 4a is a voltage detection circuit for detecting the voltage between the terminals u1 and v1 and supplies the following three types of signals from the respective outputs. That is, the output of the comparator 17a when Vr1 <VP, and the not gate 22b when Vr2> VP.
, And the output of the AND gate 26 in the case of Vr2 ≦ Vp ≦ Vr1, the output voltage “H” is supplied.

Next, the operation of the automatic voltage regulator configured as described above will be described with reference to FIGS. Terminal u1
If the voltage between -v1 rises for some reason,
That is, when Vr1 <VP, first, the voltage between the terminals u1 and v1 is transformed by the transformer 11 at a predetermined voltage ratio, rectified by the full-wave rectifier circuit 12, the voltage is smoothed by the capacitor 13, and the resistor 14, A voltage VP divided by 15 is generated. The voltage VP is compared with the reference voltage Vr1.
First, because Vr1 <VP, the comparator 17a generates the output voltage "H", and the photocoupler 31a passes through the resistor 25a.
Apply current to the diodes of b and 31c and photocoupler 3
1b and 31c are turned on, and control rectification units 33b and 3
Apply current to the input of 3c. Therefore, the secondary voltage generated by the main transformer 1 as shown in FIG. 1 is applied to the primary winding of the compensating transformer 2 by the following circuit. That is, the secondary voltage of the main transformer 1 passes through the terminal u, the electric wire 1a, and the terminal u1, the bidirectional control rectifying element 3b is turned on, passes through the primary winding of the compensation transformer 2, and the bidirectional control rectifying element 3c is turned on. It is turned on and circulates in the circuit of terminal v1, electric wire 1a and terminal v.
Therefore, the voltage between the terminals u1 and v1 is applied to the primary winding of the compensation transformer 2. The terminal u, which is the secondary winding of the compensation transformer 2.
A voltage of approximately eV is generated between 1 and u2 and between v1 and v2. Since the voltage of the eV has a polarity different from that of the secondary voltage of the main transformer 1, the voltage between the terminals u2 and v2 lowers the voltage between the terminals u1 and v1 by approximately 2 eV and suppresses the voltage rise.

On the other hand, since the output voltage of the knot gate 22a is "L", the output voltage of the AND gate 26 is "L", no current flows through the diode of the photocoupler 31e, and the photocoupler 31e is off. . Therefore, the bidirectional control rectifying element 3e is also turned off. Vr1>
Since it is Vr2, VP> Vr2, and the output voltage of the comparator 17 becomes "H". Since the output voltage of the knot gate 22b becomes "L", no current flows through the resistor 25b.
Therefore, the transistor 28 is turned off, no current flows through the diodes of the photocouplers 31a and 31d, and the photocouplers 31a and 31d are turned off, so that the bidirectional control rectification elements 3a and 3d are turned off.

Next, when the voltage between the terminals u1 and v1 drops for some reason, the voltage VP is generated across the resistor 15 in the same manner as the voltage rises. The voltage Vp is compared with the reference voltage Vr2. Since Vr2> VP, the output voltage of the comparator 17b becomes "L", the output voltage of the knot gate 22b becomes "H", and the transistor 28 is turned on through the resistor 25b. Therefore, the photocouplers 31a and 31d are turned on, and a current is supplied to the respective inputs of the control rectification units 33a and 33d. Therefore, the secondary voltage generated by the main transformer 1 as shown in FIG. 1 is applied to the primary winding of the compensating transformer 2 by the following circuit. That is, the secondary voltage of the main transformer 1 turns on the bidirectional control rectifying element 3a via the terminal u, the electric wire 1a, and the terminal u1, and passes through the primary winding of the compensating transformer 2 to the bidirectional control rectifying element 3d. It is turned on and circulates in the circuit of terminal v1, electric wire 1a and terminal v. Therefore,
Since a voltage of approximately eV is generated between the terminals u1 and u2 of the compensation transformer 2 and between v1 and v2, and the voltage of the eV has the same polarity as the output voltage of the main transformer 1, The secondary voltage of 1 is increased by almost 2 eV to compensate for the lower voltage. Since the center of the secondary winding of the main transformer 1 is grounded and the two secondary windings of the compensation transformer 2 are connected between terminals u1 and u2 and between terminals v1 and v2 respectively, At the same time, the entire voltage is supplied to the first load from both ends of the side winding terminal u2-v2, and the second load and the third load are connected between the terminals u2-N and v2-N, respectively. , The second load, the third
In the case where half the total voltage is supplied to the load, the voltage imbalance between the second load and the third load can be reduced.

Further, when the voltage between the terminals u1 and v1 is within the normal range, that is, when Vr2≤Vp≤Vr1, Vp≤V
Because of r1, the output voltage of the comparator 17a becomes "L" and the output voltage of the knot gate 22a becomes "H". On the other hand, since Vr2≤Vp, the output voltage of the comparator 17b is "H", and the output voltage of the AND gate 26 is "H".
Then, the bidirectionally controlled rectifying element 3e is turned on via the photocoupler 31e. Since the output voltage of the comparator 17a is "L", the bidirectional control rectifying elements 3b and 3c are turned off by the same operation as described above, and the output voltage of the comparator 17b is "H". The bidirectional control rectifying elements 3a and 3d are turned off by the same operation as the above. Therefore, the bidirectional control rectifying elements 3a, 3b, 3c, 3
Since d is turned off, no voltage is applied to the primary side of the compensation transformer 2. On the other hand, since the bidirectional control rectifying element 3e turns on, the primary winding of the compensating transformer 2 is shorted by the turning on, and the impedance seen from the secondary side of the compensating transformer 2 becomes low. No significant voltage drop.

Example 2. Another embodiment of the present invention will be described with reference to FIG. In FIG. 3, reference numeral 41 is a forward converter, and this forward converter 41 is a full-wave bridge that rectifies the AC voltage at the terminals u1-V1. Reference numeral 42 denotes an inverse conversion unit that converts the rectified voltage into an AC variable voltage. Here, the forward conversion unit 41 and the inverse conversion unit 42 form an inverter. The inverse conversion unit 42 is composed of transistors T1 to T4 and feedback diodes D1 to D4. 4a is the voltage detection circuit shown in FIG.
Reference numeral 43 is a known inverter control circuit that controls the inverse conversion unit 42, and 44 is a base amplifier that amplifies the output of the inverter control circuit 43.

The operation of this embodiment will be described with reference to FIGS. First, the voltage between the terminals u1 and v1 is detected by the voltage detection circuit 4a (step 100), and the terminals u1 and v1 are detected.
If the voltage between them drops for some reason, that is,
When Vr2> VP, the output voltage "H" of the comparator 17a shown in FIG.
3 is supplied to the inverter control circuit 4 by the voltage "H".
3 generates an operation signal of the inverse conversion unit 42, supplies the operation signal to the base amplifier 44, and operates the transistors T1 to T4 of the inverse conversion unit 42 to the polarity for adding the power supply voltage (step 101). Therefore, as in the first embodiment, the terminal u2-v
Suppress the voltage drop between the two. Next, when the voltage between the terminals u1 and v1 is within the normal range, that is, Vr2≤Vp≤Vr
In the case of 1, the output voltage “H” of the AND gate 26 shown in FIG. 2 of the voltage detection circuit 4a is supplied to the inverter control circuit 43, and the inverter control circuit 43 generates the operation signal of the inverse conversion unit 42, and the operation signal To the base amplifier 44 to turn on the transistors T1 and T2 or the transistors T3 and T4 to short-circuit the primary side of the compensation transformer 2 (step 10).
2). Therefore, as in the first embodiment, a significant voltage drop due to the compensating transformer 2 itself is prevented. In addition, Vr2 ≦ Vp ≦
In the case of Vr1, without using an inverter, as in Example 1,
As a configuration in which the bidirectional control rectifying element 3e of FIG. 1 is connected,
The bidirectional control rectifying element 3e may be turned on. In such a case, the control of the inverse conversion unit 42 becomes slightly easier. Further, when the voltage between the terminals u1 and v1 rises for some reason, that is, when Vr1 <VP, the voltage detection circuit 4a shown in FIG.
The output voltage “H” of the comparator 17a shown in FIG. 2 is supplied to the inverter control circuit 43, the inverter control circuit 43 generates the operation signal of the inverse conversion unit 42 by the voltage “H”, and the operation signal is supplied to the base amplifier 44. Then, the transistors T1 to T4 of the inverse converter 42 are operated to operate in the polarity for subtracting the power supply voltage (step 103). Therefore, as in the first embodiment, the increase in the voltage between the terminals u2 and v2 is suppressed.

The inverter is controlled according to the voltage between the terminals u1 and v1, and the output voltage is made stepless so that the secondary voltage of the compensation transformer 2 is generated steplessly and the terminal u2−
It is also possible to compensate for the voltage across v2. Also, terminals u1-v
Since the inverse converter 42 can be driven at the same frequency as the voltage between terminals 1, there is no need to provide a smoothing capacitor in the forward converter 41, and the device can be downsized and its life can be extended.

The above description is one embodiment of the present invention, and the present invention may be modified as follows. For example, although the polarity switching means and the opening / closing means are described as bidirectional control rectification elements, control rectification elements such as transistors may be arranged in antiparallel, or contacts of an electromagnetic contactor may be used. Further, although the number of secondary windings of the compensating transformer 2 is two, the number of secondary windings may be one. The reference voltage is Vr1
And Vr2, two types have been described, but one type may be used. The operation is as follows when there is only one reference voltage. That is, when the primary detection voltage of the compensation transformer 2 is higher than the reference voltage, the bidirectional control rectifier elements 3b and 3c are turned on so that the voltage of the secondary winding of the compensation transformer 2 is subtracted, while When the primary detection voltage of the compensation transformer 2 is lower than the reference voltage, the bidirectional control rectifying elements 3a and 3d may be turned on so that the voltage of the secondary winding of the compensation transformer 2 is added. Further, the voltage detection by the on / off control unit 4 detects the primary side of the compensation transformer 2, but it may be the secondary side of the compensation transformer 2 or the power source side or the secondary side of the main transformer 1.

Further, the control of the bidirectional control rectifying elements 3a to 3d used for the polarity switching means has been described as the on / off control, but the secondary voltage of the compensating transformer 2 is continuously changed by phase control. May be. That is, the bidirectional control rectifying element 3a,
3d or the bidirectionally controlled rectifying elements 3b and 3c are turned on, the bidirectionally controlled rectifying element is operated while the phase is controlled to apply a voltage to the primary side of the compensating transformer 2, and The secondary voltage may be changed continuously.

[0034]

As described above, according to the first aspect of the present invention, the polarity switching means for switching the polarity of the power supply voltage and the primary side winding are connected to the power source via the polarity switching means. , A transformer in which one end of the secondary winding is connected to one end of the power supply, and the secondary winding is used as a part of the load voltage,
The power supply or the load is provided with voltage detection means for detecting the voltage, and the comparison means for comparing the voltage value detected by the voltage detection means with a predetermined reference voltage value, and the detection voltage of the voltage detection means is predetermined. If the voltage is higher than the first reference voltage value, the voltage is applied to the primary winding of the transformer by the polarity switching means so that the voltage of the secondary winding of the transformer is subtracted from the power supply voltage. When the detected voltage of the voltage detecting means is lower than the second reference voltage value set in advance, the polarity switching means adds the secondary voltage of the transformer to the power supply voltage. Since the control means for applying the voltage to the primary winding is provided, there is an effect that the voltage can be easily and automatically adjusted.

According to the second aspect of the present invention, the polarity switching means for switching the polarity of the power supply voltage, the primary winding is connected to the power supply via the polarity switching means, and the secondary winding One end is connected to one end of the power supply, a transformer that uses the secondary winding as a part of the load voltage, a voltage detection unit that detects the voltage of the power supply or the load, and the voltage detection unit. Comparing means for comparing a voltage value with a predetermined reference voltage value, and when the detection voltage of the voltage detecting means is higher than the predetermined reference voltage value, the voltage of the secondary winding of the transformer is the power supply. When a voltage is applied to the primary winding of the transformer by the polarity switching means so as to be subtracted from the voltage and the detected voltage of the voltage detecting means is lower than a predetermined reference voltage value, Secondary voltage is the above power supply voltage Since a control means for applying a voltage to the primary winding of the transformer by said polarity switching means so as to be added to, the voltage can be automatically adjusted easily,
Moreover, the control means can be simplified.

According to the third aspect of the invention, when the voltage detected by the voltage detecting means is within a predetermined range, the switching means for opening and closing the primary winding of the transformer is provided. This has the effect of suppressing the winding voltage drop on the secondary side.

According to the fourth invention, the transformer is provided with two secondary windings, one end of the first secondary winding is connected to one end of the power supply, and the second secondary winding is connected to the other end of the power supply. Since one end of the secondary winding is connected and the first secondary winding and the second secondary winding are used as a part of the load voltage, there is an effect that the load voltage imbalance can be reduced. .

According to the fifth aspect of the invention, the polarity switching means can switch the polarity of the power supply and controls the phase of the voltage of the power supply. Therefore, there is an effect that the voltage can be continuously and automatically adjusted.

According to the sixth aspect of the invention, the polarity switching means is capable of switching the polarity of the power supply voltage and is an inverter for variably controlling the voltage of the power supply, so that the generation of harmonics can be suppressed and easily. It has the effect of automatically adjusting the voltage continuously.

According to the seventh aspect of the invention, the polarity switching means comprises an inverter including a forward conversion section and an inverse conversion section, and the forward conversion section comprises a full-wave bridge having no smoothing capacitor, so that a smoothing capacitor is provided. There is no need, and there is an effect that the automatic voltage regulator can be downsized and its life can be extended.

[Brief description of drawings]

FIG. 1 shows an overall wiring diagram of an automatic voltage regulator according to an embodiment of the present invention.

FIG. 2 shows a wiring diagram of an on / off control unit according to the present invention.

FIG. 3 is an overall connection diagram showing another embodiment of the present invention.

FIG. 4 shows a flowchart showing another embodiment of the present invention.

FIG. 5 is an overall view showing a conventional automatic voltage regulator.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Main transformer, 2 ... Compensation transformer, 3a-3d ... Bidirectional control rectifier (polarity switching means) 3e ... Bidirectional control rectifier (switching means) 4 ... ON / OFF control unit (voltage detection means, comparison means,
Control means) 41 ... Forward conversion unit, 42 ... Inverse conversion unit

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-3-111917 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01F 29/02 G05F 1/24

Claims (7)

(57) [Claims] 1. A polarity switching means for switching the polarity of a power supply voltage, a primary winding is connected to the power supply via the polarity switching means, and one end of a secondary winding is connected to one end of the power supply. And a transformer that uses the secondary winding as a part of the load voltage, a voltage detection unit that detects the voltage of the power supply or the load, and a voltage value that is detected by the voltage detection unit. Comparing means for comparing with the reference voltage value, the voltage of the secondary winding of the transformer is equal to the power supply voltage when the detected voltage of the voltage detecting means is higher than a predetermined first reference voltage value. A voltage is applied to the primary winding of the transformer by the polarity switching means so as to be subtracted, and the voltage detected by the voltage detecting means is lower than a second reference voltage value determined in advance, the transformer The secondary voltage of Automatic voltage regulator, characterized in that a control means for applying a voltage to the primary winding of the transformer by said polarity switching means so as to be added. 2. A polarity switching means for switching the polarity of a power supply voltage, a primary winding is connected to the power supply via the polarity switching means, and one end of the secondary winding is connected to one end of the power supply. And a transformer that uses the secondary winding as a part of the load voltage, a voltage detection unit that detects the voltage of the power supply or the load, and a voltage value that is detected by the voltage detection unit. If the detected voltage of the voltage detection means is higher than a predetermined reference voltage value, the voltage of the secondary winding of the transformer is subtracted from the power supply voltage. As described above, when the voltage is applied to the primary winding of the transformer by the polarity switching means, and the detected voltage of the voltage detecting means is lower than a predetermined reference voltage value, the secondary voltage of the transformer is Add to power supply voltage Automatic voltage regulator, characterized in that a control means for applying a voltage to the primary winding of the transformer by Uni said polarity switching means. 3. The switching device according to claim 1, further comprising an opening / closing device for opening and closing the primary winding of the transformer when the voltage detected by the voltage detecting device is within a predetermined range. Automatic voltage regulator. 4. The transformer comprises two secondary windings, one end of the first secondary winding is connected to one end of a power supply, and one end of the second secondary winding is connected to the other end of the power supply. Are connected, and the first secondary winding and the second secondary winding are used as a part of the voltage of a load, The automatic according to any one of claims 1 to 3, Voltage regulator. 5. The automatic voltage regulator according to claim 1, wherein the polarity switching means is capable of switching the polarity of the power supply voltage and phase-controls the voltage of the power supply. . 6. The automatic switching device according to claim 1, wherein the polarity switching means comprises an inverter capable of switching the polarity of the power source voltage and variably controlling the voltage of the power source. Voltage regulator. 7. The automatic voltage regulator according to claim 6, wherein the polarity switching means is an inverter including a forward converter and an inverse converter, and the forward converter is a full-wave bridge without a smoothing capacitor. vessel.