JP3690576B2 - Automatic voltage regulator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an automatic voltage regulator that is inserted in a power supply path from a single-phase power distribution system to a load.
[0002]
[Prior art]
  FIG. 11 is a circuit configuration diagram showing a conventional example of this type of automatic voltage regulator.
[0003]
  In FIG. 11, 1 is a single-phase power distribution system, 2 is an AC constant voltage device formed by a rectifier circuit, an inverter, and the like, 3 is an electromagnetic contactor, 4 is formed by a semiconductor AC switch 4a, an electromagnetic contactor 4b, and the like. A bypass switch circuit 5 indicates a load.
[0004]
  In this automatic voltage regulator, the electromagnetic contactor 3 is normally closed and the bypass switch circuit 4 is open so that the AC power of the distribution system 1 is desired by the AC constant voltage device 2 at the same frequency as that of the distribution system 1. When the AC constant voltage device 2 is malfunctioning, the bypass switch circuit 4 is closed while the malfunction is detected and the electromagnetic contactor 3 is opened.
[0005]
  At this time, the power supply path to the load 5 can be switched almost without instantaneous interruption by quickly closing the semiconductor AC switch 4a of the bypass switch circuit 4 and then closing the electromagnetic contactor 4b.
[0006]
[Problems to be solved by the invention]
  In the conventional automatic voltage regulator shown in FIG. 11, since the AC constant voltage device 2 has an output capacity equal to the rated capacity of the load 5, the conversion of the rectifier circuit and inverter constituting the AC constant voltage device 2 The capacity also becomes a value commensurate with the rated capacity of the load 5, and there is a problem that the entire apparatus becomes large and expensive.
[0007]
  In addition, in order to switch the power supply path to the load 5 almost instantaneously without interruption by the bypass switch circuit 4, the function of synchronizing the phase of the voltage output from the AC constant voltage device 2 with the phase of the voltage of the distribution system 1 is provided. It is desirable to provide the AC constant voltage device 2, and for this purpose, the circuit configuration becomes complicated compared to an AC constant voltage device that simply supplies AC power of a desired voltage to the load 5 at substantially the same frequency as the distribution system 1. There is also a problem.
[0008]
  An object of the present invention is to provide an automatic voltage regulator that solves the above problems.
[0009]
[Means for Solving the Problems]
  This first invention is provided in a power supply path from a single-phase power distribution system to a load, and includes a transformer having a primary winding and a secondary winding, a self-extinguishing element, and a diode connected in reverse parallel. 8 pairs of semiconductor switches are bridge-connected, the intermediate connection point of the first arm of the bridge connection is connected to one end of the power distribution system through an AC reactor, and the intermediate connection point of the second arm of the bridge connection is the above-mentioned Connected to the other end of the power distribution system, the intermediate connection point of the third arm of the bridge connection is connected to one end of the primary winding of the pressure device, and the intermediate connection point of the fourth arm of the bridge connection is via an LC filter An adjustment voltage generation circuit formed by connecting to the other end of the primary winding of the transformer, and a voltage control circuit for controlling the AC voltage output from the adjustment voltage generation circuit to a desired value at the same frequency as the distribution system And the transformer In automatic voltage regulator formed by connecting the load to the single-phase power distribution system via the secondary winding in series,
  The voltage control circuit compares the voltage obtained by adding the detected value of the voltage of the distribution system and the detected value of the output voltage of the adjustment voltage generating circuit with the set voltage, and the deviation between them is zero. The adjustment voltage generation circuit is controlled as described above.
[0010]
  According to a second aspect of the present invention, in the automatic voltage regulator of the first aspect, the voltage control circuit has a function of compensating for a voltage drop of the secondary winding of the transformer based on the current of the load. It is characterized by that.
[0011]
  According to a third aspect of the present invention, in the automatic voltage regulator of the first aspect, the voltage control circuit compensates for the voltage drop of the secondary winding of the transformer based on the current output from the regulated voltage generation circuit. It is characterized by the addition of a function.
[0012]
  According to a fourth aspect of the present invention, in the automatic voltage regulator of any one of the first to third aspects of the present invention, a switch circuit inserted in a path from the regulated voltage generation circuit to the primary winding of the transformer, A direct sending control circuit for controlling opening and closing of the switch circuit is added.
[0013]
  According to a fifth aspect of the present invention, in the automatic voltage regulator of the fourth aspect, the switch circuit comprises a parallel connection circuit of a semiconductor AC switch and a mechanical switch having a contact, and the switch circuit is a primary winding of the transformer. It is characterized by being connected to both ends.
[0014]
  A sixth invention is the automatic voltage regulator of the fourth invention, wherein the switch circuit is a transfer type mechanical switch, the make contact of the mechanical switch is connected to both ends of the primary winding of the transformer, The break contact is connected between one end of the adjustment voltage generating circuit and one end of the primary winding of the transformer.
[0015]
  A seventh invention is the automatic voltage regulator of the fourth invention, wherein the switch circuit is a continuous mechanical switch, and the make contact of the mechanical switch is connected to both ends of the primary winding of the transformer, The break contact is connected between one end of the adjustment voltage generating circuit and one end of the primary winding of the transformer.
[0016]
  The eighth invention is characterized in that in the automatic voltage regulator of the sixth or seventh invention, a varistor connected to both ends of the primary winding of the transformer is added.
[0017]
  A ninth invention is the automatic voltage regulator according to any one of the fourth to eighth inventions,
Normally, the current of the load is monitored while the switch circuit is opened (de-energized) by the direct control circuit, and when the load current exceeds a predetermined value, the switch is controlled by the direct control circuit. The operation of the adjustment voltage generation circuit is stopped via the voltage control circuit while the circuit is closed (excited).
[0018]
  According to a tenth aspect of the present invention, in the automatic voltage regulator of any one of the fourth to eighth aspects of the invention, the adjustment voltage generating circuit is normally set while the switch circuit is opened (non-excited) by the direct feed control circuit. When the output current of the adjustment voltage generating circuit exceeds a predetermined value, the adjustment circuit is closed via the voltage control circuit while the switch circuit is closed (excited) by the direct transmission control circuit. The operation of the voltage generation circuit is stopped.
[0019]
  According to an eleventh aspect of the present invention, in the automatic voltage regulator of the fifth aspect of the invention, during normal times, the direct current control circuit monitors the current of the semiconductor AC switch while opening the switch circuit, and the semiconductor AC switch When the current exceeds a predetermined value, the operation of the adjustment voltage generation circuit is stopped via the voltage control circuit while the switch circuit is closed by the direct transmission control circuit.
[0020]
  A twelfth aspect of the invention is the automatic voltage regulator according to the seventh aspect of the present invention, wherein the voltage control circuit causes the third and third bridge connections to be made during the period from when the continuous mechanical switch is excited to make. The upper arm semiconductor switch of each of the four arms is turned on or off, and the lower arm semiconductor switch is turned off or on.
[0021]
  A thirteenth aspect of the invention is the automatic voltage regulator according to the eighth aspect of the invention, characterized in that a capacitor for absorbing an overvoltage accompanying the operation of the mechanical switch is connected to both ends of the bridge-connected circuit.
[0022]
  According to the present invention, the main circuit of the automatic voltage regulator is formed by the transformer, the regulated voltage generating circuit, the switch circuit, and the like, so that the output capacity of the regulated voltage generating circuit is set to the load rating as will be described later. The capacity can be reduced to about 10 to 20% of the capacity. As a result, the entire apparatus can be reduced in size and price.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
  FIG. 1 is a circuit configuration diagram of an automatic voltage regulator showing a first embodiment of the present invention. Components having the same functions as those of the conventional circuit shown in FIG. 11 are denoted by the same reference numerals.
[0024]
  That is, in FIG. 1, 1 is a single-phase power distribution system, 5 is a load, 11 is an AC reactor, and 12 is an IGBT (reference sign Q) as a self-extinguishing element.₁~ Q₈) And respective diodes are connected in reverse parallel to each other, and eight sets of semiconductor switches are bridge-connected, and an adjustment voltage generating main circuit including a capacitor 12a as a snubber connected to the bridge connection circuit as shown in the figure, 13 is an adjustment An LC filter 14 for extracting a fundamental wave component from a PWM-controlled voltage waveform output from the voltage generation main circuit 12 is called a booster transformer, and has, for example, a primary winding and a secondary winding with the illustrated polarity. The transformers 15 and 16 form the adjustment voltage generating main circuit 12 so as to bring the voltage across the load 5 to a desired value.₁~ Q₈It is a voltage control circuit that controls on / off of each.
[0025]
  The adjustment voltage generation circuit 10 formed by the AC reactor 11, the adjustment voltage generation main circuit 12, and the LC filter 13 shown in FIG. 1 is referred to as a direct link type power conversion circuit. When the voltage of the primary winding (•) of the transformer 14 is in phase with the distribution system 1 and is stepped down with respect to the voltage to the secondary winding (•), Q₁(Or Q_Four) And Q₂(Or Q_Three) Are in opposite phases to each other, and are turned on or off in synchronization with the zero phase of the voltage of the distribution system 1, for example, Q_Five~ Q₈Q_FiveAnd Q₆Are turned on or off in synchronization with the distribution system 1 and the zero phase of the voltage by PWM control with opposite phases.₈And Q₇The control of turning on or off in synchronization with the zero phase of the voltage of the distribution system 1 is performed by any of the voltage control circuits 15 and 16 described later.
[0026]
  In addition, the voltage of the primary winding (•) of the transformer 14 is opposite to that of the distribution system 1 with respect to the voltage from the distribution system 1 to the secondary winding (•) of the transformer 14, and Q.₁(Or Q_Four) And Q₂(Or Q_Three) Are in opposite phases to each other, and are turned on or off in synchronization with the zero phase of the voltage of the distribution system 1, for example, Q_Five~ Q₈Q₆And Q_FiveAre turned on or off in synchronization with the distribution system 1 and the zero phase of the voltage by PWM control with opposite phases.₇And Q₈The control of turning on or off in synchronization with the zero phase of the voltage of the distribution system 1 is performed by any of the voltage control circuits 15 and 16 described later.
[0027]
  That is, if the voltage of the secondary winding (•) of the transformer 14 and the voltage of the primary winding (•) are in phase with each other, the voltage across the load 5 is adjusted to the voltage of the distribution system 1. The voltage output from the circuit 10 is subtracted through the transformer 14, and the voltage of the secondary winding (• mark) and the voltage of the primary winding (• mark) of the transformer 14 are opposite in phase to each other. If so, the voltage across the load 5 is a value obtained by adding the voltage output from the adjustment voltage generation circuit 10 to the voltage of the distribution system 1 via the transformer 14.
[0028]
  FIG. 2 is a detailed circuit diagram of the voltage control circuit 15 shown in FIG. 1 showing the first embodiment of the present invention. In order to operate the voltage control circuit 15, transformers (PT) 6 and 7 and a current transformer (CT) 8 shown in FIG. 2 are added to the circuit configuration of the automatic voltage regulator shown in FIG. Has been.
[0029]
  The operation of the voltage control circuit 15 shown in FIG. 2 will be described below.
[0030]
  First, the voltage of the distribution system 1 is detected by the PT 6, the detected value is rectified by the rectifier 21, the noise component is removed while smoothing the rectified value via the delay element 22, and the adjustment voltage generating circuit 10 detects the voltage output by the PT 7, rectifies the detected value by the rectifier 23, smooths the rectified value through the delay element 24, removes the noise component, and converts the smoothed value and the transformer 14 is multiplied by the multiplier 25, and the adder 26 calculates the multiplication value of the multiplier 25 from the output value of the delay element 22.Addition / subtraction according to forward / reverse phaseAs a result, the voltage across the load 5 is obtained as shown in the following formula (1).
[0031]
  Voltage across load 5 ≒ Voltage of distribution system 1
                  ± Output voltage of the regulated voltage generator 10 × K (1)
Here, “±” in the second term on the right side is “+” if the phase of the voltage of the secondary winding (• mark) and the voltage of the primary winding (• mark) of the transformer 14 are opposite to each other. Then with "-"Meaning to add.
[0032]
  Further, “≈” between the left side and the right side of the above formula (1) is caused by the voltage drop of the secondary winding based on the voltage fluctuation rate of the transformer 14 due to the current of the load 5.
[0033]
  Therefore, in order to make the left side and the right side of the formula (1) more equal, the current of the load 5 is detected in CT8, the detected value is rectified by the rectifier 27, and the rectified value is passed through the delay element 28. The value obtained by removing the noise component while smoothing is multiplied by the voltage fluctuation rate “δ” by the multiplier 29, and the multiplication value of the multiplier 29 is subtracted by the multiplication calculator 30 from the output value of the addition calculator 26. The voltage regulator 32 performs a proportional integral (PI) calculation that makes the deviation between the subtracted value and the set value from the load voltage setter 31 zero.
[0034]
  Accordingly, the gate control circuit 33 performs an operation based on the output value of the voltage regulator 32 and the synchronization signal obtained from the PT 6, and forms the adjustment voltage generating main circuit 12 based on the operation result.₁~ Q₈By turning each on and off as described above, the voltage across the load 5 can be set to the value set by the load voltage setting unit 31.
[0035]
  FIG. 3 is a detailed circuit configuration diagram of the voltage control circuit 16 shown in FIG. 1 showing the second embodiment of the present invention. Components having the same functions as those of the embodiment circuit shown in FIG. A description thereof will be omitted. In order to operate the voltage control circuit 15, transformers (PT) 6 and 7 and a current transformer (CT) 9 shown in FIG. 3 are added to the circuit configuration of the automatic voltage regulator shown in FIG. Has been.
[0036]
  That is, the voltage control circuit 16 shown in FIG. 3 includes a rectifier 34, a delay element 35, and a multiplier 36 instead of the rectifier 27 and the delay element 28 of the voltage control circuit 16 shown in FIG. The output current of the voltage generator 10 is detected, the detected value is rectified by the rectifier 34, and the rectified value is smoothed through the delay element 35, and the noise component is removed, and the transformation ratio of the transformer 14 By multiplying the reciprocal of “K” by the multiplier 36, this multiplication value can be made substantially the same as the value obtained by the delay element 28 described above.
[0037]
  For example, in the circuit configuration of the automatic voltage regulator shown in FIGS. 1 to 3, with respect to the rated voltage of the distribution system 1, the secondary voltage of the transformer 14 is transferred from the regulated voltage generation circuit 10 through the transformer 14. By setting the superimposed voltage to at most 10%, the output capacity of the adjustment voltage generating circuit 10 can be made about 10% of the rated capacity of the load 5.
[0038]
  FIG. 4 is a circuit diagram of an automatic voltage regulator showing a second embodiment of the present invention. Components having the same functions as those of the first embodiment shown in FIG. The description thereof is omitted here.
[0039]
  That is, the automatic voltage regulator shown in FIG. 4 includes, in addition to the regulated voltage generation circuit 10, the transformer 14, and the voltage control circuit 15a or 16a, a semiconductor AC switch 17a and an electromagnetic contactor 17b in which thyristors are connected in reverse parallel. The switch circuit 17 to be formed and any one of direct transmission control circuits 40 to 42 for controlling opening and closing of the switch circuit 17 are provided.
[0040]
  In addition to the function of the voltage control circuit 15 (or 16), the voltage control circuit 15a (or 16a) controls the gate control circuit 33 described above by a signal from any one of direct transmission control circuits 40 to 42 described later. Through the Q forming the adjustment voltage generating main circuit 12₁~ Q₈A function is added to turn off everything and stop the power conversion operation of the adjustment voltage generation main circuit 12.
[0041]
  FIG. 5 is a detailed circuit diagram of the direct transmission control circuit 40 shown in FIG. 4 showing the third embodiment of the present invention. In order to operate the direct control circuit 40, transformers (PT) 6 and 7 and a current transformer (CT) 8 shown in FIG. 5 are added to the circuit configuration of the automatic voltage regulator shown in FIG. Has been.
[0042]
  The operation of the direct feed control circuit 40 shown in FIG. 5 will be described below.
[0043]
  Normally, the voltage across the load 5 is set to a desired value by the adjustment voltage generation circuit 10, the transformer 14, and the voltage control circuit 15a while the switch circuit 17 is opened by the direct transmission control circuit 40.
[0044]
  At this time, the voltage of the distribution system 1 obtained by the PT 6 and the rectifier 51 is monitored by the comparator 52 and the comparator 53, and the voltage of the distribution system 1 is overvoltage “V”._IH”, The comparator 52 operates and the output thereof becomes a logic“ H ”level, and the voltage of the distribution system 1 becomes the undervoltage“ V ”._IL", The comparator 53 operates and its output becomes a logic" H "level. Further, the voltage output from the adjustment voltage generation circuit 10 obtained by the PT 7 and the rectifier 54 is monitored by the comparator 55, and the voltage output from the adjustment voltage generation circuit 10 due to an abnormal operation of the adjustment voltage generation circuit 10 is overvoltage “V_CH”, The comparator 55 operates and its output becomes a logic“ H ”level. Further, the current of the load 5 obtained by the CT 8 and the rectifier 56 is monitored by the comparator 57, and the current of the load 5 is overcurrent “I” due to a short circuit of the load 5 or the like._OH”, The comparator 57 operates and the output becomes a logic“ H ”level.
[0045]
  When the output of at least one of the above-described comparators 52, 53, 55, 57 becomes a logic “H” level, the output of the OR element 58 changes from a logic “L” level to a logic “H” level. . When the output of the OR element 58 becomes a logic “H” level, the voltage control circuit 15a forms the adjustment voltage generating main circuit 12 via the gate control circuit 33 described above.₁~ Q₈The switch circuit 17 is changed from the open state to the closed state via the drive circuit 59 while turning off all of them.
[0046]
  That is, when the output of the OR element 58 changes from the logic “L” level to the logic “H” level, the semiconductor AC switch 17a of the switch circuit 17 is quickly closed, and the electromagnetic contactor 17 having the operation delay is closed. By doing so, the primary winding of the transformer 14 is fed from the distribution system 1 to the load 5 through the secondary winding in a short-circuit state with almost no instantaneous interruption.
[0047]
  At this time, the phase change of the supply voltage to the load 5 immediately before and immediately after the switch circuit 17 is closed is slight, and the semiconductor AC switch 17a may be selected with a current value rated for a short time. Furthermore, by monitoring the voltage of the power distribution system 1 with the comparator 52 and the comparator 53 and monitoring the current of the load 5 with the comparator 57, it is possible to prevent the adjustment voltage generation circuit 10 from being damaged.
[0048]
  FIG. 6 is a detailed circuit configuration diagram of the direct transmission control circuit 41 shown in FIG. 4 showing the fourth embodiment of the present invention. Components having the same functions as those in the embodiment circuit shown in FIG. A description thereof will be omitted. In order to operate the direct transmission control circuit 41, transformers (PT) 6 and 7 and a current transformer (CT) 9 shown in FIG. 6 are added to the circuit configuration of the automatic voltage regulator shown in FIG. Has been.
[0049]
  That is, the direct transmission control circuit 41 shown in FIG. 6 includes a rectifier 60 and a comparator 61 instead of the rectifier 56 and the comparator 57 of the direct transmission control circuit 40 shown in FIG.
[0050]
  The operation of the direct feed control circuit 41 shown in FIG. 6 will be described below.
[0051]
  Normally, the voltage across the load 5 is set to a desired value by the adjustment voltage generation circuit 10, the transformer 14, and the voltage control circuit 16a while the switch circuit 17 is opened by the direct transmission control circuit 41.
[0052]
  At this time, the current output from the adjustment voltage generation circuit 10 obtained by the CT 9 and the rectifier 60 is monitored by the comparator 61, and the current output from the adjustment voltage generation circuit 10 due to a short circuit of the load 5 is the overcurrent “I_CH", The comparator 61 operates and its output becomes a logic" H "level.
[0053]
  When the output of at least one of the above-described comparators 52, 53, 55, 61 becomes a logic “H” level, the output of the OR element 58 changes from a logic “L” level to a logic “H” level. . When the output of the OR element 58 becomes a logic “H” level, the voltage control circuit 16a forms the adjustment voltage generating main circuit 12 via the gate control circuit 33 described above.₁~ Q₈The switch circuit 17 is changed from the open state to the closed state via the drive circuit 59 while turning off all of them.
[0054]
  That is, when the output of the OR element 58 changes from the logic “L” level to the logic “H” level, the semiconductor AC switch 17a of the switch circuit 17 is quickly closed, and the electromagnetic contactor 17 having the operation delay is closed. By doing so, the primary winding of the transformer 14 is fed from the distribution system 1 to the load 5 through the secondary winding in a short-circuit state with almost no instantaneous interruption.
[0055]
  At this time, the phase change of the supply voltage to the load 5 immediately before and immediately after the switch circuit 17 is closed is slight, and the semiconductor AC switch 17a may be selected with a current value rated for a short time. Further, the voltage of the distribution system 1 is monitored by the comparator 52 and the comparator 53, and the current output from the adjustment voltage generation circuit 10 is monitored by the comparator 61, thereby preventing the adjustment voltage generation circuit 10 from being damaged. Can do.
[0056]
  FIG. 7 is a detailed circuit configuration diagram of the direct transmission control circuit 42 shown in FIG. 4 showing the fifth embodiment of the present invention. Components having the same functions as those of the embodiment circuit shown in FIG. A description thereof will be omitted. In order to operate this direct transmission control circuit 42, transformers (PT) 6 and 7 and a current transformer (CT) 9 shown in FIG. 6 are added to the circuit configuration of the automatic voltage regulator shown in FIG. Has been.
[0057]
  In this circuit configuration, the insertion position of CT9 is different from the circuit of the embodiment shown in FIG.
[0058]
  The operation of the direct feed control circuit 42 shown in FIG. 7 will be described below.
[0059]
  During normal operation, the direct-current control circuit 42 opens the semiconductor AC switch 17a and the electromagnetic contactor 17b constituting the switch circuit 17, while the adjustment voltage generation circuit 10, the transformer 14, and the voltage control circuit 16a allow the load 5 Is set to a desired value.
[0060]
  At this time, the current output from the adjustment voltage generation circuit 10 obtained by the CT 9 and the rectifier 60 is monitored by the comparator 62 and adjusted by erroneous firing and short-circuit failure of the semiconductor AC switch 17a, short-circuit of the load 5, etc. The current output from the voltage generation circuit 10 is an overcurrent “I_SH”, The comparator 62 operates and its output becomes a logic“ H ”level.
[0061]
  When the output of at least one of the above-described comparators 52, 53, 55, 62 becomes a logic “H” level, the output of the OR element 58 changes from a logic “L” level to a logic “H” level. . When the output of the OR element 58 becomes a logic “H” level, the voltage control circuit 16a forms the adjustment voltage generating main circuit 12 via the gate control circuit 33 described above.₁~ Q₈The switch circuit 17 is changed from the open state to the closed state via the drive circuit 59 while turning off all of them.
[0062]
  In other words, with the circuit configuration shown in FIG. 7, in addition to the function of the circuit configuration shown in FIG. Damage can also be prevented.
[0063]
  FIG. 8 is a circuit configuration diagram of an automatic voltage regulator showing a third embodiment of the present invention. Components having the same functions as those in the circuit of the second embodiment shown in FIG. The description thereof is omitted here.
[0064]
  That is, in the automatic voltage regulator shown in FIG. 8, in addition to the regulated voltage generation circuit 10, the transformer 14, and the voltage control circuit 15b or 16b, both the break contact is opened and the make contact is closed. Are provided with a switch circuit 18 formed of a so-called transfer-type mechanical switch, a varistor 19, and any one of direct transmission control circuits 40 to 42 for controlling opening and closing of the switch circuit 18. Yes.
[0065]
  In addition to the function of the voltage control circuit 15 (or 16), the voltage control circuit 15b (or 16b) generates a signal from any one of the direct transmission control circuits 40 to 42, and the mechanical switch makes the make-up. After that, the Q for forming the adjustment voltage generating main circuit 12 through the gate control circuit 33 is formed.₁~ Q₈A function is added to turn off everything and stop the power conversion operation of the adjustment voltage generation main circuit 12.
[0066]
  The varistor 18 is provided to absorb an overvoltage that may be generated in the primary winding of the transformer 14 during the period between the break of the mechanical switch and the make and the contact chatter immediately after the make.
[0067]
  FIG. 9 is a circuit configuration diagram of an automatic voltage regulator showing a fourth embodiment of the present invention. Components having the same functions as those in the circuit of the second embodiment shown in FIG. The description thereof is omitted here.
[0068]
  That is, the automatic voltage regulator shown in FIG. 9 includes a break contact and a make contact, unlike the transfer type mechanical switch described above, in addition to the adjustment voltage generation circuit 10, the transformer 14, and the voltage control circuit 15c or 16c. And a switching circuit 20 formed of a so-called continuous type mechanical switch that has once lost the period in which the circuit is open, and any one of direct transmission control circuits 40 to 42 that control the opening and closing of the switching circuit 20. Yes.
[0069]
  In addition to the function of the voltage control circuit 15 (or 16), the voltage control circuit 15c (or 16c) emits a signal from any of the direct transmission control circuits 40 to 42, and the mechanical switch makes the make-up. During the period until the adjustment, the Q that forms the adjustment voltage generating main circuit 12 is connected via the gate control circuit 33 described above._Five, Q₇(Or Q₆, Q₈), The overvoltage that may be generated in the primary winding of the transformer 14_Five, Q₇(Or Q₆, Q₈) To form the regulated voltage generating main circuit 12 after the circuit is suppressed and the mechanical switch is made₁~ Q₈A function is added to turn off everything and stop the power conversion operation of the adjustment voltage generation main circuit 12.
[0070]
  FIG. 10 is a circuit configuration diagram of an automatic voltage regulator showing a fifth embodiment of the present invention. Components having the same functions as those of the circuit of the second embodiment shown in FIG. The description thereof is omitted here.
[0071]
  That is, the automatic voltage regulator shown in FIG. 10 includes, in addition to the regulated voltage generation circuit 10, the transformer 14, and the voltage control circuit 15b or 16b, a switch circuit 20 formed from a continuous mechanical switch, and a switch circuit. 20 and any one of direct feed control circuits 40 to 42 for controlling opening and closing.
[0072]
  The difference between this embodiment circuit and the embodiment circuit shown in FIG. 9 is that one of the direct feed control circuits 40 to 42 described above is used instead of the capacitor 12a as a snubber constituting the adjustment voltage generating main circuit 12. And a capacitor 12b having a capacity capable of absorbing the overvoltage between the primary windings of the transformer 14 which may occur during the period until the mechanical switch is made.
[0073]
【The invention's effect】
  According to this invention, the main circuit of the automatic voltage regulator is formed by a transformer, a regulated voltage generating circuit, a switch circuit, etc., so that the output capacity of the regulated voltage generating circuit is about 10 to 20% of the rated capacity of the load. As a result, the entire apparatus can be reduced in size and price.
[0074]
  Further, the switch circuit can prevent the adjustment voltage generation circuit from being damaged due to an overload, and as a result, a highly reliable automatic voltage adjustment device can be provided.
[Brief description of the drawings]
FIG. 1 is a circuit configuration diagram of an automatic voltage regulator showing a first embodiment of the invention.
FIG. 2 is a circuit configuration diagram of an automatic voltage regulator showing a first embodiment of the invention.
FIG. 3 is a circuit configuration diagram of an automatic voltage regulator showing a second embodiment of the present invention.
FIG. 4 is a circuit configuration diagram of an automatic voltage regulator showing a second embodiment of the present invention.
FIG. 5 is a circuit configuration diagram of an automatic voltage regulator showing a third embodiment of the present invention.
FIG. 6 is a circuit configuration diagram of an automatic voltage regulator showing a fourth embodiment of the present invention.
FIG. 7 is a circuit configuration diagram of an automatic voltage regulator showing a fifth embodiment of the present invention.
FIG. 8 is a circuit configuration diagram of an automatic voltage regulator showing a third embodiment of the present invention.
FIG. 9 is a circuit configuration diagram of an automatic voltage regulator showing a fourth embodiment of the present invention.
FIG. 10 is a circuit configuration diagram of an automatic voltage regulator showing a fifth embodiment of the invention.
FIG. 11 is a circuit configuration diagram of an automatic voltage regulator showing a conventional example.
[Explanation of symbols]
  DESCRIPTION OF SYMBOLS 1 ... Distribution system, 2 ... AC constant voltage apparatus, 3 ... Magnetic contactor, 4 ... Bypass switch circuit, 4a ... Semiconductor alternating current switch, 4b ... Electromagnetic contactor, 5 ... Load, 6, 7 ... PT, 8, 9 ... CT: 10 ... Adjusted voltage generating circuit, 11 ... AC reactor, 12 ... Adjusted voltage generating main circuit, 12a ... Capacitor, 13 ... LC filter, 14 ... Transformer, 15, 15a, 15b, 15c, 16, 16a, 16b, 16c: Voltage control circuit, 17, 18, 20 ... Switch circuit, 17a ... Semiconductor AC switch, 17b ... Electromagnetic contactor, 19 ... Varistor, 21, 23, 27, 34 ... Rectifier, 22, 24, 28, 35 ... Delay Elements 25, 29, 36... Multipliers 26, 30... Addition calculator 31. , 56 and 60 ... Rectifier, 52,53,55,57,61,62 ... comparator, 58 ... OR element, 59 ... driving circuit.

Claims (13)

8 sets of semiconductor switches provided in a power supply path from a single-phase power distribution system to a load, and having a primary winding and a secondary winding, and a self-extinguishing element and a diode connected in reverse parallel Bridge connection, the intermediate connection point of the first arm of the bridge connection is connected to one end of the distribution system via an AC reactor, and the intermediate connection point of the second arm of the bridge connection is connected to the other end of the distribution system And an intermediate connection point of the third arm of the bridge connection is connected to one end of the primary winding of the voltage transformer, and an intermediate connection point of the fourth arm of the bridge connection is connected to the primary winding of the transformer via an LC filter. An adjustment voltage generator circuit connected to the other end of the power supply circuit, and a voltage control circuit that controls the AC voltage output from the adjustment voltage generator circuit to a desired value at the same frequency as the distribution system. The secondary winding of the instrument in series In automatic voltage regulator formed by connecting the load to the single-phase distribution system and,
The voltage control circuit compares the voltage obtained by adding the detected value of the voltage of the distribution system and the detected value of the output voltage of the adjustment voltage generating circuit with the set voltage, and the deviation between them is zero. The automatic voltage regulator is characterized by controlling the regulated voltage generating circuit as described above. In the automatic voltage regulator of Claim 1 ,
2. An automatic voltage regulator according to claim 1, wherein a function of compensating for a voltage drop of the secondary winding of the transformer is added to the voltage control circuit based on the current of the load. In the automatic voltage regulator of Claim 1 ,
Said voltage control circuit, the adjustment voltage based on the current output from the generator, the transformer of the automatic voltage regulator, characterized in that an additional function of compensating for the voltage drop of the secondary winding. In the automatic voltage regulator according to any one of claims 1 to 3,
2. An automatic voltage regulator comprising: a switch circuit inserted in a path from the regulated voltage generation circuit to a primary winding of a transformer; and a direct transmission control circuit for controlling opening and closing of the switch circuit. In the automatic voltage regulator of Claim 4,
2. The automatic voltage regulator according to claim 1, wherein the switch circuit comprises a parallel connection circuit of a semiconductor AC switch and a mechanical switch having a contact, and the switch circuit is connected to both ends of the primary winding of the transformer. In the automatic voltage regulator of Claim 4,
The switch circuit is a transfer type mechanical switch, the make contact of the mechanical switch is connected to both ends of the primary winding of the transformer, and the break contact is one end of the adjustment voltage generating circuit and the primary winding of the transformer. An automatic voltage regulator characterized by being connected between one end of a wire. In the automatic voltage regulator of Claim 4,
The switch circuit is a continuous mechanical switch, the make contact of the mechanical switch is connected to both ends of the primary winding of the transformer, and the break contact is one end of the adjustment voltage generating circuit and the primary winding of the transformer. An automatic voltage regulator characterized by being connected between one end of a wire. In the automatic voltage regulator of Claim 6 or Claim 7,
An automatic voltage regulator comprising a varistor connected to both ends of the primary winding of the transformer. In the automatic voltage regulator in any one of Claims 4 thru | or 8,
Normally, the current of the load is monitored while the switch circuit is opened (de-energized) by the direct control circuit, and when the load current exceeds a predetermined value, the switch is controlled by the direct control circuit. An automatic voltage adjusting device, wherein the operation of the adjustment voltage generating circuit is stopped via the voltage control circuit while the circuit is closed (excited). In the automatic voltage regulator in any one of Claims 4 thru | or 8,
Normally, the output current of the adjustment voltage generation circuit is monitored while the switch circuit is opened (de-energized) by the direct feed control circuit, and when the output current of the adjustment voltage generation circuit exceeds a predetermined value An automatic voltage adjustment device characterized in that the operation of the adjustment voltage generation circuit is stopped via the voltage control circuit while the switch circuit is closed (excited) by the direct transmission control circuit. In the automatic voltage regulator of Claim 5,
Normally, the current of the semiconductor AC switch is monitored while the switch circuit is opened by the direct control circuit, and when the current of the semiconductor AC switch exceeds a predetermined value, the switch is controlled by the direct control circuit. An automatic voltage regulator, wherein the operation of the regulated voltage generation circuit is stopped via the voltage control circuit while the circuit is closed. In the automatic voltage regulator of Claim 7,
In the period from when the continuous mechanical switch is excited to make, the upper and lower arm semiconductor switches of the third and fourth arms of the bridge connection are turned on or off by the voltage control circuit. An automatic voltage regulator characterized by turning a switch off or on. In the automatic voltage regulator of Claim 7,
2. An automatic voltage regulator according to claim 1, wherein a capacitor for absorbing an overvoltage associated with the operation of the mechanical switch is connected to both ends of the bridge-connected circuit.

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