JP6081039B1 - Regenerative converter - Google Patents

Abstract

  The regenerative converter 100 includes a power conversion unit 12, an AC terminal 11 connected to the AC side of the power conversion unit 12, a first terminal connected to one end of the DC side of the power conversion unit 12, and a backflow prevention element. A second terminal connected to one end on the DC side of the power converter, a third terminal connected to the other end on the DC side of the power converter 12, and a first terminal and a third terminal And a detection circuit that detects whether a wiring is connected to each of the wirings, and whether the wiring is connected to each of the second terminal and the third terminal.

Description

  The present invention relates to a regenerative converter that converts electric power supplied from a power source and outputs the converted electric power to a load and converts electric power supplied from the load and outputs the converted electric power to the power source.

  The regenerative converter is a power converter that is arranged between an inverter that performs variable speed control of an AC motor and an AC power source, and that regenerates the induced electromotive force generated when the AC motor is decelerated to the AC power source. The conventional power converter shown in Patent Document 1 has both the functions of a regenerative converter and the function of an inverter, and can be used as a single inverter or a single regenerative converter, so that it is easy to use and can improve productivity. .

JP 7-194144 A

  Regenerative converters are classified into two types, one of which is the power conversion section of the main circuit that constitutes the regenerative converter, both the power running current supplied from the AC power source to the AC motor and the regenerative current regenerated from the AC motor to the AC power source. The other is a converter in which only the regenerative current flows to the power converter. Hereinafter, in order to simplify the description, the former converter is referred to as a full regenerative converter and the latter is referred to as a partial regenerative converter. In the all regenerative converter, a power running current flows to the power conversion unit, whereas in the partial regenerative converter, a power running current preventing diode is provided to prevent the power running current from flowing to the power conversion unit. Therefore, the full regenerative converter and the partial regenerative converter cannot be shared. The prior art disclosed in Patent Document 1 has both the function of a regenerative converter and the function of an inverter, but does not have both the functions of a full regenerative converter and the function of a partial regenerative converter. Since all the regenerative converters which can respond to electric power are needed, the subject that the unit size reduction of a regenerative converter was aimed at cannot be met.

  The present invention has been made in view of the above, and an object thereof is to obtain a regenerative converter capable of further reducing the unit size.

  In order to solve the above-described problems and achieve the object, the regenerative converter of the present invention is a regenerative converter that converts AC power into DC power and converts DC power into AC power, and includes a power conversion unit, power An AC terminal connected to the AC side of the converter, a first terminal connected to one end of the DC side of the power converter, and a first terminal connected to one end of the DC side of the power converter via a backflow prevention element 2, a third terminal connected to the other end on the DC side of the power conversion unit, and a wiring is connected to each of the first terminal and the third terminal, or the second terminal and the third terminal And a detection circuit for detecting whether a wiring is connected to each of the terminals.

  The regenerative converter according to the present invention has an effect that the unit size can be further reduced.

Configuration diagram of regenerative converter according to an embodiment Configuration diagram of inverter connected to regenerative converter shown in FIG. The figure which shows the example of a connection of the regenerative converter when the regenerative converter shown in FIG. 1 is used as a full regenerative converter, and the inverter shown in FIG. The figure which shows the example of a connection of the regenerative converter when the regenerative converter shown in FIG. 1 is used as a partial regenerative converter, and the inverter shown in FIG. The figure which shows the structural example of the detection circuit which detects the connection state of the regenerative converter shown in FIG. 1, and the inverter shown in FIG. The figure for demonstrating operation | movement of a detection circuit when the regenerative converter shown in FIG. 5 is used as a full regenerative converter. The figure for demonstrating operation | movement of a detection circuit when the regenerative converter shown in FIG. 5 is used as a partial regenerative converter.

  Hereinafter, a regenerative converter according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment.
FIG. 1 is a configuration diagram of a regenerative converter according to an embodiment, and FIG. 2 is a configuration diagram of an inverter connected to the regenerative converter shown in FIG. A regenerative converter 100 shown in FIG. 1 includes an AC terminal 11, a power converter 12 connected to the AC terminal 11 and configured by a plurality of switching elements, a DC terminal 16, an inrush current prevention circuit 13, and a power running current prevention. Diode 14 and main circuit capacitor 15. In the following description, the AC terminal 11 side of the power conversion unit 12 is referred to as “AC side of the power conversion unit 12”, and the DC terminal 16 side of the power conversion unit 12 is referred to as “DC side of the power conversion unit 12”.

  The DC terminal 16 is connected to the positive electrode bus P which is one end on the DC side of the power converter 12 via the inrush current prevention circuit 13 and also connected to the positive terminal P constituting the DC terminal 24 of the inverter 200 shown in FIG. A first terminal P1 to be connected is provided. The DC terminal 16 is connected to the positive bus P of the power converter 12 via the power running current prevention diode 14 and connected to the positive terminal P constituting the DC terminal 24 of the inverter 200 shown in FIG. Two terminals P2 are provided. The DC terminal 16 is connected to a negative electrode bus Q which is the other end of the DC side of the power converter 12 and is connected to a negative terminal N constituting the DC terminal 24 of the inverter 200 shown in FIG. A terminal N1 is provided.

  One end of the inrush current prevention circuit 13 is connected to a connection point between the positive electrode bus P on the DC side of the power converter 12 and the power running current prevention diode 14, and the other end is connected to the main circuit capacitor 15 and the first terminal P1. Connected to the connection point. The power running current prevention diode 14 is an example of a backflow prevention element that prevents a current flowing from the power conversion unit 12 to the second terminal P2, that is, a power running current. In the illustrated example, the anode is connected to the second terminal P2. The cathode is connected to the inrush current prevention circuit 13.

  One end of the main circuit capacitor 15 is connected to the connection point between the inrush current prevention circuit 13 and the first terminal P1, and the other end is connected to the negative electrode bus Q on the DC side of the power converter 12 and the third terminal N1. Connected to a point. The arrangement relationship among the first terminal P1, the second terminal P2, the third terminal N1, the powering current prevention diode 14, and the inrush current prevention circuit 13 is not limited to the illustrated example, and the powering current prevention is performed. The power diode 14 and the inrush current prevention circuit 13 may be connected to the negative electrode bus Q on the DC side of the power converter 12 and the direction of the power running current prevention diode 14 may be reversed.

  The power conversion unit 12 includes a series circuit including a switching element 12a and a switching element 12d, a series circuit including a switching element 12b and a switching element 12e, and a switching element 12c and a switching element 12f. A series circuit. The power conversion unit 12 includes a diode 12a1 connected in parallel with the switching element 12a, a diode 12b1 connected in parallel with the switching element 12b, and a diode 12c1 connected in parallel with the switching element 12c. The power conversion unit 12 includes a diode 12d1 connected in parallel with the switching element 12d, a diode 12e1 connected in parallel with the switching element 12e, and a diode 12f1 connected in parallel with the switching element 12f.

  The connection point between the switching element 12c and the switching element 12f is connected to the R phase terminal of the AC terminal 11, the connection point between the switching element 12b and the switching element 12e is connected to the S phase terminal of the AC terminal 11, and the switching element 12a A connection point with the switching element 12 d is connected to a T-phase terminal of the AC terminal 11. A switching signal output from a control circuit (not shown) is input to each of the six switching elements 12a, 12b, 12c, 12d, 12e, and 12f.

  The inverter 200 illustrated in FIG. 2 includes an AC terminal 21, a rectifier circuit 22 that includes a plurality of rectifier diodes and is connected to the AC terminal 21, and an AC terminal 27. The inverter 200 includes a plurality of switching elements, and converts the DC power supplied from the rectifier circuit 22 or the DC power supplied from the regenerative converter 100 shown in FIG. 1 into AC power, and via the AC terminal 27. A power conversion unit 26 that converts supplied AC power into DC power is provided. The inverter 200 includes an inrush current prevention circuit 23 connected to the positive bus P between the rectifier circuit 22 and the power conversion unit 26, a DC terminal 24, and one end of the inrush current prevention circuit 23 and the power conversion unit 26. The capacitor 25 is connected to the positive electrode bus P between them and the other end is connected to the negative electrode bus Q between the rectifier circuit 22 and the power converter 26.

  The positive terminal P constituting the DC terminal 24 is connected to the positive bus P between the inrush current prevention circuit 23 and the power converter 26, and the negative terminal N constituting the DC terminal 24 is connected to the rectifier circuit 22 and the power converter. 26 is connected to the negative electrode bus Q between them.

  3 is a diagram showing a connection example between the regenerative converter and the inverter shown in FIG. 2 when the regenerative converter shown in FIG. 1 is used as a full regenerative converter. When the regenerative converter 100 is used as a full regenerative converter, the AC power source 1 is connected to the AC terminal 11 of the regenerative converter 100 via the reactor 2, and the DC terminal of the inverter 200 is connected to the first terminal P1 of the regenerative converter 100. 24 is connected to the third terminal N1 of the regenerative converter 100, and the negative terminal N of the DC terminal 24 of the inverter 200 is connected to the third terminal N1 of the regenerative converter 100. In inverter 200, AC electric motor 3 is connected to a U-phase terminal, a V-phase terminal, and a W-phase terminal constituting AC terminal 27. The first terminal P1 and the positive terminal P are connected by a wiring 41, and the third terminal N1 and the negative terminal N are connected by a wiring.

  Hereinafter, operations of regenerative converter 100 and inverter 200 shown in FIG. 3 will be described. After describing the operation of the AC motor 3 during powering, the operation of the AC motor 3 during regeneration will be described.

  When the AC motor 3 is powered, the AC power supplied from the AC power source 1 is converted into DC power by the plurality of diodes constituting the power conversion unit 12, and the converted DC power passes through the DC terminal 16 and the DC terminal 24. Then, it is supplied to the power converter 26. By operating a plurality of switching elements constituting the power conversion unit 26 according to a switching signal output from a control circuit (not shown), the power conversion unit 26 converts DC power into AC power, and the AC power is transmitted through the AC terminal 27. Are supplied to the AC motor 3, and the AC motor 3 is driven by the supply of AC power.

  During regeneration of the AC motor 3, AC power supplied from the AC motor 3 is converted into DC power by a plurality of diodes constituting the power conversion unit 26, and the converted DC power passes through the DC terminal 24 and the DC terminal 16. And supplied to the power converter 12. When a plurality of switching elements constituting the power conversion unit 12 operate according to a switching signal output from a control circuit (not shown), the power conversion unit 12 converts DC power into AC power, and the AC power is converted into AC terminal 11 and a reactor. It is regenerated to the AC power source 1 through 2.

  4 is a diagram showing a connection example between the regenerative converter and the inverter shown in FIG. 2 when the regenerative converter shown in FIG. 1 is used as a partial regenerative converter. When the regenerative converter 100 is used as a partial regenerative converter, the AC power source 1 is connected to the AC terminal 11 of the regenerative converter 100 via the reactor 2, and the DC terminal of the inverter 200 is connected to the second terminal P2 of the regenerative converter 100. 24 is connected to the third terminal N1 of the regenerative converter 100, and the negative terminal N of the DC terminal 24 of the inverter 200 is connected to the third terminal N1 of the regenerative converter 100. In inverter 200, AC power supply 1 is connected to AC terminal 21, and AC electric motor 3 is connected to a U-phase terminal, a V-phase terminal, and a W-phase terminal constituting AC terminal 27. The second terminal P2 and the positive terminal P are connected by a wiring 41, and the third terminal N1 and the negative terminal N are connected by a wiring 42.

  Hereinafter, operations of regenerative converter 100 and inverter 200 shown in FIG. 4 will be described. After describing the operation of the AC motor 3 during powering, the operation of the AC motor 3 during regeneration will be described.

  During powering of the AC motor 3, AC power supplied from the AC power supply 1 is converted into DC power by the plurality of rectifier diodes constituting the rectifier circuit 22, and the converted DC power is supplied to the power converter 26. By operating a plurality of switching elements constituting the power conversion unit 26 according to a switching signal output from a control circuit (not shown), the power conversion unit 26 converts DC power into AC power, and the AC power is transmitted through the AC terminal 27. Are supplied to the AC motor 3, and the AC motor 3 is driven by the supply of AC power. At this time, since no current flows through the power conversion unit 12 due to the power running current prevention diode 14, the power conversion unit 12 does not perform power conversion.

  During regeneration of the AC motor 3, AC power supplied from the AC motor 3 is converted into DC power by a plurality of diodes constituting the power conversion unit 26, and the converted DC power passes through the DC terminal 24 and the DC terminal 16. And supplied to the power converter 12. When a plurality of switching elements constituting the power conversion unit 12 operate according to a switching signal output from a control circuit (not shown), the power conversion unit 12 converts DC power into AC power, and the AC power is converted into AC terminal 11 and a reactor. It is regenerated to the AC power source 1 through 2.

  As described above, the regenerative converter 100 functions as a partial regenerative converter by connecting the DC terminal 24 of the inverter 200 to the second terminal P2 and the third terminal N1. Further, by connecting the DC terminal 24 of the inverter 200 to the first terminal P1 and the third terminal N1, the regenerative converter 100 functions as a full regenerative converter. Therefore, the regenerative converter 100 can cope with both the partial regenerative converter and the full regenerative converter by changing the connection to the first terminal P1, the second terminal P2, and the third terminal N1.

  Thus, regenerative converter 100 has both the functions of a full regenerative converter and the function of a partial regenerative converter, but has three terminals connected to the direct current side of power converter 12, so that the user can connect wiring 41 and There is a possibility that the wiring 42 is miswired. As an example of erroneous wiring, when the regenerative converter 100 is operated as a full regenerative converter as shown in FIG. 3, one end of the wiring 41 is connected to the second terminal P2 instead of the first terminal P1. . Another example of erroneous wiring is to connect one end of the wiring 41 to the first terminal P1 instead of the second terminal P2 when the regenerative converter 100 is operated as a partial regenerative converter as shown in FIG. .

  Hereinafter, a configuration example will be described in which the regenerative converter 100 and the inverter 200 are prevented from operating in a miswired state.

  FIG. 5 is a diagram illustrating a configuration example of a detection circuit that detects a connection state between the regenerative converter illustrated in FIG. 1 and the inverter illustrated in FIG. 2. The detection circuit 500 shown in FIG. 5 has a resistance element 53 having one end connected to the connection point between the second terminal P2 of the regenerative converter 100 and the powering current prevention diode 14, and a resistance having one end connected to the resistance element 53. And an element 54. The detection circuit 500 has one end connected to a connection point between the first terminal P1 of the regenerative converter 100, the main circuit capacitor 15, and the inrush current prevention circuit 13, and one end connected to the other end of the resistance element 51. The resistor element 52 is connected, and the other end is connected to a connection point between the third terminal N1 of the regenerative converter 100 and the main circuit capacitor 15.

  The detection circuit 500 includes a comparator 55 having a non-inverting input terminal 56, an inverting input terminal 57, and an output terminal 58. The non-inverting input terminal 56 is connected to a connection point between the resistance element 53 and the resistance element 54, and the inverting input terminal 57 is connected to a connection point between the resistance element 51 and the resistance element 52.

  One end of the first voltage dividing circuit 50-1 including the resistance element 53 and the resistance element 54 is connected to the second terminal P2, and the other end is connected to the third terminal N1. One end of the second voltage dividing circuit 50-2 including the resistance element 51 and the resistance element 52 is connected to the first terminal P1, and the other end is connected to the third terminal N1.

  The detection circuit 500 is connected to a connection state determination circuit 600 that determines the connection state of the wiring 41 to the regenerative converter 100 according to the output level of the comparator 55. In FIG. 5, the detection circuit 500 and the connection state determination circuit 600 are disposed outside the regenerative converter 100, but the detection circuit 500 and the connection state determination circuit 600 may be disposed inside the regenerative converter 100.

  Hereinafter, the operation of the detection circuit 500 will be described.

FIG. 6 is a diagram for explaining the operation of the detection circuit when the regenerative converter shown in FIG. 5 is used as a full regenerative converter. When the power is turned on in the connection state of FIG. 6, the main circuit capacitor 15 of the regenerative converter 100 and the capacitor 25 of the inverter 200 are charged, and between the first terminal P1 and the third terminal N1, A potential difference occurs. At this time, since nothing is connected to the second terminal P2, there is no potential difference between the second terminal P2 and the third terminal N1. Therefore, the voltage divided by the first voltage dividing circuit 50-1 is lower than the voltage divided by the second voltage dividing circuit 50-2. In this case, the comparator 55 compares the voltage applied to the non-inverting input terminal 56 with the voltage applied to the inverting input terminal 57, and outputs a Low level signal. When the inverter is not connected to the second terminal P2, ideally, no current flows through the resistance element 53 and the resistance element 54 because there is the power running current prevention diode 14. That is, there is no voltage difference between P2 and N1, so there is no potential difference. However, since a slight current flows due to the leakage current of the power running current prevention diode 14 in practice, the resistance of the non-inverting input terminal 56 becomes smaller than the voltage of the inverting input terminal 57 even if this leakage current flows. It is necessary to adjust the element 53 and the resistance element 54. The adjustment conditions are as follows.
(1) At the time of partial regenerative connection, the condition that the potential difference between P2 and N1 is larger than the potential difference between P1 and N1 is satisfied.
(2) The difference between the potential difference between P2 and N and the potential difference between P1 and N1 does not exceed the rated specification of the comparator 55.
(3) The condition that the potential difference between P1 and N1 is larger than the potential difference between P2 and N1 at the time of full regenerative connection.
When the leakage current of the power running current preventing diode 14 is large, it is necessary to reduce the resistance element 53 and the resistance element 54 in order to satisfy the adjustment condition (3). However, when the resistance element 51 and the resistance element 52 are determined in advance, in order to simultaneously satisfy the adjustment conditions (1) and (3), it is necessary to connect a resistor (not shown) to consume the leakage current. There is.

  FIG. 7 is a diagram for explaining the operation of the detection circuit when the regenerative converter shown in FIG. 5 is used as a partial regenerative converter. When the power is turned on in the connection state of FIG. 7, the main circuit capacitor 15 of the regenerative converter 100 and the capacitor 25 of the inverter 200 are charged, and a potential difference is generated between the second terminal P2 and the third terminal N1. Arise. At this time, the potential of the first terminal P1 is a value obtained by subtracting the forward voltage of the powering current preventing diode 14 from the potential of the second terminal P2. However, when the forward voltage of the power running current prevention diode 14 is smaller than the potential difference between the second terminal P2 and the third terminal N1, the voltage between the second terminal P2 and the third terminal N1 The potential difference is equal to the potential difference between the first terminal P1 and the third terminal N1. Here, the voltage dividing ratio between the resistance element 53 and the resistance element 54 is adjusted so that the voltage applied to the non-inverting input terminal 56 is larger than the voltage applied to the inverting input terminal 57. In this case, the comparator 55 compares the voltage applied to the non-inverting input terminal 56 with the voltage applied to the inverting input terminal 57, and outputs a high level signal.

  The signal output from the output terminal 58 of the comparator 55 is input to the connection state determination circuit 600. When the signal output from the output terminal 58 is at the low level, the connection state determination circuit 600 performs wiring as shown in FIG. It is determined that 41 and 42 are connected. Further, when the signal output from the output terminal 58 is at a high level, the connection state determination circuit 600 determines that the wirings 41 and 42 are connected as shown in FIG. Information on these determination results is transmitted to display means or sound output means (not shown).

  The display means displays character information indicating the connection state based on the information transmitted from the connection state determination circuit 600. Examples of the display information include “connection state usable as a full regenerative converter” or “connection state usable as a partial regenerative converter”.

  The voice output unit reproduces voice guidance indicating the connection state based on the information transmitted from the connection state determination circuit 600. Examples of the voice guidance include “a connection state usable as a full regenerative converter” or “a connection state usable as a partial regenerative converter”.

  Accordingly, the user can know whether the regenerative converter 100 is in a connection state when used as a full regenerative converter or whether the regenerative converter 100 is in a connection state when used as a partial regenerative converter. Therefore, it is possible to prevent the regenerative converter 100 and the inverter 200 from operating in a connection state that is not intended by the user, that is, a miswired state.

  The connection location of the inrush current prevention circuit 13 according to the present embodiment is not limited to the illustrated example. That is, instead of the inrush current prevention circuit 13 shown in FIG. 1, one end is connected to the positive pole bus P on the DC side of the power converter 12, and the other end is a connection point between the power running current prevention diode 14 and the first terminal P1. You may use the inrush current prevention circuit connected to. In this case, the cathode of the power running current prevention diode 14 is connected to the connection point between the first terminal P 1 and the main circuit capacitor 15.

  In addition, the detection circuit 500 according to the present embodiment uses the resistance element 53 and the resistance element 54 in the first voltage dividing circuit 50-1, thereby floating between the second terminal P2 and the third terminal N1. The charge charged in the capacitor can be consumed. More specifically, when a leakage current flows in the reverse direction in the power running current prevention diode 14, the potential difference between the second terminal P2 and the third terminal N1 increases. This leakage current continues to flow until the potential difference between the second terminal P2 and the third terminal N1 becomes equal to the potential difference between the first terminal P1 and the third terminal N1. As described above, when operating in full regeneration, the potential of the second terminal P2 needs to be lower than the potential of the first terminal P1. Since the electric charge charged in the stray capacitance by the resistive element 53 and the resistive element 54 is consumed, the potential of the second terminal P2 becomes lower than the potential of the first terminal P1, and the value of the resistive element varies. Even in this case, the detection accuracy of the connection state in the detection circuit 500 is improved.

  As described above, the regenerative converter according to the present embodiment includes the first terminal, the second terminal, and the third terminal. Both the partial regenerative converter and the full regenerative converter can be supported. By switching the connection of the DC terminal composed of the first terminal, the second terminal, and the third terminal, the function of the full regenerative converter and the function of the partial regenerative converter can be exhibited. Therefore, it is possible to further reduce the unit size.

  In addition, the regenerative converter according to the present embodiment detects whether a wiring is connected to each of the first terminal and the third terminal or whether a wiring is connected to each of the second terminal and the third terminal. A detection circuit is provided. With this configuration, it is possible to prevent the regenerative converter and the inverter from operating in a state where they are erroneously wired to the three terminals connected to the DC side of the power conversion unit.

  In the first voltage dividing circuit according to the present embodiment, when the forward voltage of the backflow prevention element is smaller than the potential difference between the second terminal and the third terminal, the forward voltage of the backflow prevention element is A resistance element is provided that inverts the output of the comparator depending on the case where the potential difference is larger than the potential difference between the second terminal and the third terminal. According to this configuration, the output of the comparator can be changed simply by changing the value of the resistance element, and the connection state can be accurately determined while suppressing an increase in unit size.

  The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

  1 AC power source, 2 reactor, 3 AC motor, 11, 21, 27 AC terminal, 12, 26 power converter, 12a, 12b, 12c, 12d, 12e, 12f switching element, 12a1, 12b1, 12c1, 12d1, 12e1, 12f1 diode, 13, 23 Inrush current prevention circuit, 14 power running current prevention diode, 15 main circuit capacitor, 16, 24 DC terminal, 22 rectifier circuit, 25 capacitor, 41, 42 wiring, 50-1 first voltage dividing circuit 50-2 Second voltage dividing circuit 51, 52, 53, 54 Resistance element 55 Comparator 56 Non-inverting input terminal 57 Inverting input terminal 58 Output terminal 100 Regenerative converter 200 Inverter 500 Detection circuit 600 Connection state determination circuit.

Claims (6)

A regenerative converter that converts AC power into DC power and converts DC power into AC power,
A power converter,
An AC terminal connected to the AC side of the power converter;
A first terminal connected to one end on the DC side of the power converter;
A second terminal connected to one end of the power conversion unit on the direct current side through a backflow prevention element;
A third terminal connected to the other end of the DC side of the power converter;
A detection circuit configured to detect whether a wiring is connected to each of the first terminal and the third terminal or whether a wiring is connected to each of the second terminal and the third terminal. Regenerative converter characterized by.   2. An inrush current prevention circuit having one end connected to one end on the DC side of the power conversion unit and the other end connected to a connection point between the backflow prevention element and the first terminal. Regenerative converter described in.   2. An inrush current prevention circuit having one end connected to a connection point between one end on the DC side of the power converter and the backflow prevention element and the other end connected to the first terminal. Regenerative converter described in. The detection circuit includes:
A first voltage dividing circuit connected between the second terminal and the third terminal;
A second voltage dividing circuit connected between the first terminal and the third terminal;
The comparator according to any one of claims 1 to 3, further comprising: a comparator that compares the voltage divided by the first voltage dividing circuit with the voltage divided by the second voltage dividing circuit. The regenerative converter according to one item.   In the first voltage dividing circuit, when the forward voltage of the backflow prevention element is smaller than the potential difference between the second terminal and the third terminal, the forward voltage of the backflow prevention element is 5. The regenerative converter according to claim 4, further comprising a resistance element that inverts the output of the comparator when the potential difference between the second terminal and the third terminal is larger than the potential difference between the second terminal and the third terminal.   6. The regenerative converter according to claim 4, wherein the first voltage dividing circuit includes a resistance element that consumes an electric charge charged in the second terminal.

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