WO2014119374A1

WO2014119374A1 - Precharge circuit

Info

Publication number: WO2014119374A1
Application number: PCT/JP2014/050698
Authority: WO
Inventors: 芳賀　浩之
Original assignee: 新電元工業株式会社
Priority date: 2013-02-04
Filing date: 2014-01-16
Publication date: 2014-08-07
Also published as: JP2016059084A

Abstract

A precharge circuit comprising an input power supply, a capacitor to be charged by the input power supply, a switch which is inserted between the input power supply and the capacitor, an input power supply, and a charging unit which is inserted between the input power supply and the capacitor, wherein the switch is turned on after the capacitor is charged to the peak voltage of the input power supply or higher by the charging unit, thereby suppressing an inrush current to the capacitor.

Description

Precharge circuit

The present invention relates to a circuit for precharging a capacitor.
This application claims priority based on Japanese Patent Application No. 2013-019049 for which it applied to Japan on February 4, 2013, and uses the content here.

FIG. 9 is an example of a circuit diagram showing a power supply device having a conventional precharge circuit, which is disclosed in Patent Document 1 as a prior art. The power supply device provided with this precharge circuit includes an AC power supply 6, a capacitor 2 charged by the AC power supply 6, a switch 3, a rectifying unit 11 inserted between the AC power supply 6 and the capacitor 2, and a switch 3. A resistor 46 connected in parallel, a converter 47 whose input terminal is connected to the capacitor 2, and a load device 48 connected to the output terminal of the converter 47 are provided. The rectifying unit 11 is configured by bridge-connecting

diodes

7, 8, 9, and 10, and an AC terminal is connected to a series circuit of the AC power supply 6 and the switch 3, and a DC terminal is connected to the capacitor 2.

If the resistor 46 does not exist, a large inrush current flows because there are only parasitic elements such as wiring inductance and wiring resistance that suppress the charging current of the capacitor 2 when the switch 3 is turned on. Due to this inrush current, the power supply voltage is lowered, and other devices connected to the AC power supply 6 malfunction.

In order to avoid this problem, the power supply device is generally provided with a precharge circuit. However, simply inserting a resistor that limits the inrush current causes a large loss in this resistor when the power supply device supplies power to the load. In order to avoid this problem, an element that short-circuits the inrush current limiting resistor is often connected.

The operation of the power supply device provided with the precharge circuit shown in FIG. 9 is as follows. That is, when the AC power supply 6 is connected and charging of the capacitor 2 starts and it is determined that the precharge is sufficiently performed by a control means (not shown), the switch 3 which has been turned off is turned on and the converter 47 operates. And power is supplied to the load device 48. As a result, it is possible to avoid the occurrence of a constant large loss in the resistor 46 while suppressing the inrush current.

In describing the precharge circuit, since the operations of the converter 47 and the load device 48 are not directly related to each other, the description is omitted in the following description to avoid complexity.

FIG. 10 is another example of a circuit diagram showing a power supply device having a conventional precharge circuit.
The power supply device provided with the precharge circuit includes an AC power supply 6, a capacitor 2 charged by the AC power supply 6, a switch 3 and a converter 32 inserted between the AC power supply 6 and the capacitor 2, and a switch 3 in parallel. And a resistor 46 connected to the.

The converter 32 includes a choke 19,

diodes

20, 21, 22, 23,

capacitors

24, 25,

MOSFETs

26, 27, 28, 29.

Diodes

20 and 21 and

MOSFETs

26 and 27 are connected in this order as a series circuit. The cathode of the diode 20 and the source of the MOSFET 27 in this series circuit are connected to the capacitor 2.

Diodes

22 and 23 and

MOSFETs

28 and 29 are connected in this order as a series circuit. The cathode of the diode 22 and the source of the MOSFET 29 in this series circuit are connected to the capacitor 2. A capacitor 24 is connected to the cathode of the diode 21 and the source of the MOSFET 26. A capacitor 25 is connected to the cathode of the diode 23 and the source of the MOSFET 28. One end of the choke 19 is connected to a connection point between the anode of the diode 21 and the drain of the MOSFET 26. The other end of the choke 19 is connected to the switch 3 and a resistor 46 connected in parallel thereto. A connection point between the anode of the diode 23 and the drain of the MOSFET 28 is connected to the other end of the AC power supply 6.

The converter 32 is a circuit in which a flying capacitor type three-level boost chopper circuit is applied to the PFC, and the

capacitors

24 and 25 are called flying capacitors. By controlling the

MOSFETs

26, 27, 28, and 29 so that the voltage of the flying capacitor becomes 1/2 of the voltage of the capacitor 2, the voltage applied to the

diodes

20, 21, 22, and 23 and the

MOSFETs

26, 27, 28, and 29 is reduced. Since the voltage is ½ of the voltage of the capacitor 2, there is a feature that a low breakdown voltage element can be used.
The number of levels can be changed by changing the number of diodes and MOSFETs connected in series, and is generally called a multilevel converter. Non-Patent Document 2 discloses a flying capacitor type three-level boost chopper circuit.

FIG. 11 is an example of a circuit diagram showing the converter 47.
The converter 47 includes

capacitors

33, 34, 45,

diodes

35, 36, 42, 43,

MOSFETs

37, 38, 39, 40, a transformer 41, and a choke 44. A series circuit of

capacitors

33 and 34 is connected to the capacitor 2. A series circuit in which the

MOSFETs

37, 38, 39 and 40 are connected in this order is connected to the capacitor 2. The anode of the diode 35 is connected to the connection point of the

capacitors

33 and 34, and the cathode is connected to the connection point of the

MOSFETs

37 and 38. The cathode of the diode 36 is connected to the connection point between the

capacitors

33 and 34, and the anode is connected to the connection point between the

MOSFETs

39 and 40. The primary winding of the transformer 41 is connected between the connection point of the

capacitors

33 and 34 and the connection point of the

MOSFETs

38 and 39. One end of the secondary winding of the transformer 41 and the anode of the diode 42 are connected, the other end of the tertiary winding of the transformer 41 and the anode of the diode 43 are connected, and the other end of the secondary winding of the transformer 41 And one end of the tertiary winding of the transformer 41 are connected to form a series circuit. A series circuit of the choke 44 and the capacitor 45 is connected to a series circuit of the secondary winding of the transformer 41 and the diode 42, and the load device 48 is connected to the capacitor 45.

The converter 47 is a diode clamp type three-level half-bridge converter. By controlling the

MOSFETs

37, 38, 39, 40 so that the voltage of the

capacitors

33, 34 becomes 1/2 of the voltage of the capacitor 2, the voltage applied to the

MOSFETs

37, 38, 39, 40 becomes 1 / of the voltage of the capacitor 2. Therefore, a low breakdown voltage element can be used.
The number of levels can be changed by changing the number of MOSFETs connected in series, and is generally called a multi-level converter. The converter 47 is disclosed in Non-Patent Document 3.

JP-A-5-30650

However, the power supply device provided with the precharge circuit shown in FIG. 9 has a problem in that the power supply device provided with the precharge circuit cannot be downsized because the ratio of the resistor 46 to the device is large.

Resistor 46 must withstand the inrush current of the number of uses expected for the life of the device and maintain its performance. For this reason, it is necessary to reduce the stress applied to the component within an allowable range, and it is necessary to take measures such as increasing the number of components to disperse the stress, or using a large component to increase the allowable stress. For this reason, the size tends to increase.

Also, elements used for the switch 3 include mechanical contacts such as relays and semiconductor elements such as triacs. Mechanical contacts have the advantage of low conduction loss, but have a limited number of lifetimes for opening and closing the contacts. Although the semiconductor element has a longer life than the mechanical contact, the semiconductor element has a larger conduction loss than the mechanical contact. Therefore, the cooling means such as a heat sink for cooling the semiconductor element is enlarged, and a precharge circuit is provided. There was a problem that the power supply could not be miniaturized.

Also, as shown in FIG. 10, when a conventional precharge circuit is combined with a flying capacitor type multi-level converter, there is a problem that a low breakdown voltage element cannot be used. This is because the flying capacitor is not charged even though the capacitor 2 is charged by the precharge circuit.

When the capacitor 24 is not charged at all and the MOSFET 27 is turned on while the voltage is zero volts, the voltage of the capacitor 2 is applied to the diode 20. Therefore, when the diode 20 is a low breakdown voltage element assuming a voltage half that of the capacitor 2, the diode 20 may be broken.

Similarly, if the capacitor 25 is not charged at all and the MOSFET 29 is turned on with the voltage being zero volts, the voltage of the capacitor 2 is applied to the diode 22. Therefore, when the diode 22 is a low breakdown voltage element assuming a voltage half that of the capacitor 2, the diode 22 may be broken.

Further, when the capacitor 24 is not charged at all and the diode 20 is turned on with the voltage being zero volts, the voltage of the capacitor 2 is applied to the MOSFET 27. Therefore, when the MOSFET 27 is a low breakdown voltage element assuming a voltage half that of the capacitor 2, the MOSFET 27 may be broken.

Similarly, when the capacitor 25 is not charged at all and the diode 22 is turned on with the voltage being zero volts, the voltage of the capacitor 2 is applied to the MOSFET 29. Therefore, if the MOSFET 29 is a low breakdown voltage element assuming a voltage half that of the capacitor 2, the MOSFET 29 may be broken.

For this reason, when a conventional precharge circuit is combined with a flying capacitor type multi-level converter, there is a problem that the characteristics of the multi-level converter that can reduce loss by using a low withstand voltage element cannot be utilized.

Further, as shown in FIG. 11, when a diode clamp type multi-level converter is used as the converter 47 connected to the subsequent stage of the capacitor 2, there is a problem that the element withstand voltage cannot be lowered to the original withstand voltage.

When the

capacitors

33 and 34 in FIG. 11 are charged with the conventional precharge circuit shown in FIGS. 9 and 10, since the two capacitors are charged with the same current, there is a difference in charge voltage due to variations in capacitance. Arise. Therefore, it should be assumed that half the voltage of capacitor 2 should be sufficient, but it is assumed that a higher voltage is applied in anticipation of the worst value of variation, and an element with a higher withstand voltage must be used. I must.
When the voltage fluctuation of the capacitor due to charging is Δv, the charging current is i, the capacitance is C, and the charging time is Δt

There is a relationship. Since the

capacitors

33 and 34 are charged with the same current, i and Δt are common. Therefore, the variation of Δv is determined by the variation of C. For example, if you expect a variation of C of ± 20%

It becomes. Therefore, if the voltage of the capacitor 2 is 400V, it should be assumed that 200V should be assumed, but it must be assumed that it takes up to 240V, and there is a problem that an element having a higher withstand voltage than the original must be used. .

A power supply device including a precharge circuit according to the first aspect of the present invention includes a first input power supply 1, a capacitor 2 charged by the first input power supply 1, a first input power supply 1 and a capacitor 2 A switch 3 inserted between the second input power source 4 and a charging unit inserted between the second input power source 4 and the capacitor 2.

The power supply device including the precharge circuit according to the second aspect of the present invention includes an AC power supply 6 that is a first input power supply, a capacitor 2 that is charged by the AC power supply 6, and between the AC power supply 6 and the capacitor 2. The switch 3 and the rectifier 11 inserted in the second input power source 4, the second input power source 4, and the charging unit 5 inserted between the second input power source 4 and the capacitor 2. The rectifying unit 11 is configured by bridge-connecting

diodes

A power supply device including a precharge circuit according to a third aspect of the present invention includes an AC power supply 6, a capacitor 2 charged by the AC power supply 6, a switch 3 inserted between the AC power supply 6 and the capacitor 2, and A rectifying unit 11, a battery 12 as a second input power source, and a charging unit 5 inserted between the battery 12 and the capacitor 2 are provided. The rectifying unit 11 is configured by bridge-connecting

diodes

A power supply device including a precharge circuit according to a fourth aspect of the present invention includes an AC power supply 6, a capacitor 2 charged by the AC power supply 6, a switch 3 inserted between the AC power supply 6 and the capacitor 2, and A rectifying unit 11, a battery 12, and a charging unit 5 inserted between the battery 12 and the capacitor 2 are provided. The rectifying unit 11 is configured by bridge-connecting

diodes

7, 8, 9, and 10, and an AC terminal is connected to a series circuit of the AC power supply 6 and the switch 3, and a DC terminal is connected to the capacitor 2. The charging unit 5 includes a transformer 13, a MOSFET 14, and a diode 15. A primary circuit of the transformer 13 and a series circuit of the MOSFET 14 are connected to the battery 12. A series circuit of the secondary winding of the transformer 13 and the diode 15 is a capacitor. 2 is connected.

A power supply device including a precharge circuit according to a fifth aspect of the present invention includes an AC power supply 6, a capacitor 2 charged by the AC power supply 6, a switch 3 inserted between the AC power supply 6 and the capacitor 2, and A rectifying unit 11, a battery 12, and a charging unit 5 inserted between the battery 12 and the capacitor 2 are provided. The rectifying unit 11 is configured by bridge-connecting

diodes

7, 8, 9, and 10, and an AC terminal is connected to a series circuit of the AC power supply 6 and the switch 3, and a DC terminal is connected to the capacitor 2. The charging unit 5 includes a transformer 13, a MOSFET 14, and a diode 15. A primary circuit of the transformer 13 and a series circuit of the MOSFET 14 are connected to the battery 12. A series circuit of the secondary winding of the transformer 13 and the diode 15 is a capacitor. 2 is connected. The switch 3 is built in the power supply device 16, and components other than the AC power source 6, the switch 3, and the battery 12 are built in the charger 18, and the battery 12 and the charger 18 are built in the automobile 17.

A power supply device including a precharge circuit according to a sixth aspect of the present invention includes an AC power supply 6, a capacitor 2 charged by the AC power supply 6, a switch 3 inserted between the AC power supply 6 and the capacitor 2, and The converter 32, the battery 12, and the charging unit 5 inserted between the battery 12 and the capacitor 2 are provided. The converter 32 includes a choke 19,

diodes

20, 21, 22, 23,

capacitors

24, 25,

MOSFETs

26, 27, 28, 29, and the

diodes

20, 21,

MOSFETs

26, 27 are connected in this order as a series circuit. The diode 20 and the MOSFET 27 of this series circuit are connected to the capacitor 2, the

diodes

22 and 23, the

MOSFETs

28 and 29 are connected as a series circuit in this order, and the diode 22 and the MOSFET 29 of this series circuit are connected to the capacitor 2. 24 is connected to the series circuit of the diode 21 and the MOSFET 26, the capacitor 25 is connected to the series circuit of the diode 23 and the MOSFET 28, and one end of the choke 19 is connected to the connection point of the diode 21 and the MOSFET 26. The other end is connected to a switch 3, a connection point of the diodes 23 and MOSFET28 are connected to the other end of the AC power supply 6. The charging unit 5 includes a transformer 13, a MOSFET 14, and

diodes

15, 30, and 31. A primary circuit of the transformer 13 and a series circuit of the MOSFET 14 are connected to the battery 12, and a secondary winding and a tertiary winding of the transformer 13. And a series circuit of the diode 15 is connected to the capacitor 2, a series circuit of the secondary winding of the transformer 13 and the diode 30 is connected to a series circuit of the MOSFET 27 and the capacitor 24, and a series of the secondary winding of the transformer 13 and the diode 31 is connected. The circuit is connected to a series circuit of a MOSFET 29 and a capacitor 25.

A power supply device including a precharge circuit according to a seventh aspect of the present invention includes a capacitor 2 charged by an AC power supply (not shown), a converter 47 connected to the capacitor 2, a battery 12, and the battery 12 and the capacitor 2 And a charging unit 5 inserted between the two. The converter 47 includes

capacitors

33, 34, 45,

diodes

35, 36, 42, 43,

MOSFETs

37, 38, 39, 40, a transformer 41, and a choke 44, and a series circuit of the

capacitors

33, 34 is connected to the capacitor 2. A series circuit in which the

MOSFETs

37, 38, 39, 40 are connected in this order is connected to the capacitor 2, the diode 35 is connected to the connection point of the

capacitors

33, 34, and the diode 35 is connected to the connection point of the

MOSFETs

37, 38. The diode 36 is connected to the connection point of the

capacitors

33 and 34, the diode 36 is connected between the connection points of the

MOSFETs

39 and 40, and the primary winding of the transformer 41 is connected to the connection point of the

capacitors

33 and 34 and the

MOSFETs

38 and 39. Connected between the connection points, the secondary winding of the transformer 41 and the diode Are connected to each other, the secondary winding of the transformer 41 and the diode 43 are connected, and the secondary winding of the transformer 41 and the tertiary winding of the transformer 41 are connected to form a series circuit. A series circuit of 44 and a capacitor 45 is connected to a series circuit of the secondary winding of the transformer 41 and the diode 42. The charging unit 5 includes a transformer 13, a MOSFET 14, and

diodes

15 and 30. A primary circuit of the transformer 13 and a series circuit of the MOSFET 14 are connected to the battery 12, and a tertiary winding of the transformer 13 and the diode 15 are connected. A series circuit composed of the secondary winding, the tertiary winding and the diode 15 of the transformer 13 is connected to the capacitor 2, and a series circuit composed of the secondary winding of the transformer 13 and the diode 30 is connected to the capacitor 34. Has been.

The precharge circuit according to the aspect of the present invention has the following three effects.

First, since the inrush current limiting resistor can be deleted, the power supply device equipped with the precharge circuit can be downsized.

Second, if there is already a switch that disconnects the first input power supply upstream of the power supply with a precharge circuit, the switch that shorts the inrush current limiting resistor can be deleted. The power supply device including the circuit can be further reduced in size.

Third, when the multilevel converter and the precharge circuit of the present invention are combined, the flying capacitor and the capacitor 2 can be charged at the same time, so that even if a low breakdown voltage element is used, a voltage exceeding the element breakdown voltage is applied to the semiconductor element. There is no.

FIG. 1 is a circuit diagram showing Embodiment 1 of the present invention. FIG. 2 is a circuit diagram showing Embodiment 2 of the present invention. FIG. 3 is a circuit diagram showing Embodiment 3 of the present invention. FIG. 4 is a circuit diagram showing Embodiment 4 of the present invention. FIG. 5 is a circuit diagram showing Embodiment 5 of the present invention. FIG. 6 is a circuit diagram showing Embodiment 6 of the present invention. FIG. 7 is a waveform diagram showing the precharge voltage waveform of FIG. FIG. 8 is a circuit diagram showing Embodiment 7 of the present invention. FIG. 9 shows an example of a conventional precharge circuit. FIG. 10 shows another example of a conventional precharge circuit. FIG. 11 is an example of a multilevel converter.

The mode for carrying out the present invention will be apparent from the following description of the preferred embodiments when read with reference to the accompanying drawings. However, the drawings are only for explanation and do not limit the scope of the present invention.
[Example 1]

(Configuration of Example 1)
FIG. 1 is a circuit diagram illustrating a power supply device including a precharge circuit according to a first embodiment of the present invention.
The power supply device including the precharge circuit includes a first input power supply 1, a capacitor 2 charged by the first input power supply 1, and one end of the first input power supply 1 and one end of the capacitor 2. An inserted switch 3, a second input power supply 4, and a charging unit 5 inserted between the second input power supply 4 and the capacitor 2 are provided.

(Operation of Example 1)
In the power supply device having the precharge circuit according to the first embodiment configured as described above, the charging unit 5 charges the capacitor 2 to a voltage equal to or higher than the voltage of the first input power supply 1 and then turns on the switch 3 to turn on the inrush current. No longer flows.

In the first place, the inrush current flows because the voltage of the capacitor 2 is lower than the voltage of the first input power supply 1, and therefore the charging unit 5 charges the capacitor 2 to be higher than the voltage of the first input power supply 1. If the situation is solved, there will be no inrush current.

(Effect of Example 1)
In the conventional precharge circuit in which the second input power supply 4 does not exist, the capacitor 2 has to be charged using the voltage of the first input power supply 1, so that the inrush current limiting resistor is enlarged. However, if the charging unit 5 is formed using the second input power source 4, the inrush current limiting resistor can be eliminated and the capacitor 2 can be charged with an arbitrary current. Since the charging unit 5 can be reduced by reducing the charging current, the power supply device including the precharge circuit as a whole can be reduced in size.
[Example 2]

(Configuration of Example 2)
FIG. 2 is a circuit diagram showing a power supply device including a precharge circuit according to the second embodiment of the present invention.
The power supply device including the precharge circuit includes an AC power supply 6 as a first input power supply, a capacitor 2 charged by the AC power supply 6, a switch 3 inserted between the AC power supply 6 and the capacitor 2, and rectification. Unit 11, second input power supply 4, and charging unit 5 inserted between second input power supply 4 and capacitor 2.

The rectification unit 11 is configured by bridge-connecting

diodes

7, 8, 9, and 10. The AC terminal of the rectifying unit 11 is connected to the series circuit of the AC power source 6 and the switch 3, and the DC terminal is connected to the capacitor 2.

(Operation of Example 2)
In the power supply device having the precharge circuit according to the second embodiment configured as described above, an inrush current flows by turning on the switch 3 after charging the capacitor 2 to the peak voltage of the AC power supply 6 by the charging unit 5. Disappear.

(Effect of Example 2)
Since the inrush current limiting resistor can be eliminated, and the charging unit 5 can be made smaller by reducing the charging current, it is possible to reduce the size of the power supply device including the precharge circuit as a whole.
[Example 3]

(Configuration of Example 3)
FIG. 3 is a circuit diagram showing a power supply device including a precharge circuit according to Embodiment 3 of the present invention.
The power supply device including the precharge circuit includes an AC power supply 6, a capacitor 2 charged by the AC power supply 6, a switch 3 and a rectifier 11 inserted between the AC power supply 6 and the capacitor 2, a second A battery 12 as an input power source and a charging unit 5 inserted between the battery 12 and the capacitor 2 are provided.

The rectification unit 11 is configured by bridge-connecting

diodes

(Operation of Example 3)
In the power supply device having the precharge circuit according to the third embodiment configured as described above, an inrush current flows by turning on the switch 3 after charging the capacitor 2 to the peak voltage of the AC power supply 6 by the charging unit 5. Disappear.

As an example of a power supply device, for example, in the case of a charger mounted on an automobile, there is a second input to which a 12V battery is input in addition to a first input to which a commercial AC power supply is connected. By charging the capacitor 2 using the second input and the charging unit 5, the inrush current limiting resistor can be eliminated.
In such an application, since the AC power source 6 and the battery 12 generally require electrical insulation, the charging unit 5 needs to have an insulation function.

(Effect of Example 3)
Since the inrush current limiting resistor can be eliminated, and the charging unit 5 can be made smaller by reducing the charging current, it is possible to reduce the size of the power supply device including the precharge circuit as a whole.
[Example 4]

(Configuration of Example 4)
FIG. 4 is a circuit diagram showing a power supply device including a precharge circuit according to the fourth embodiment of the present invention.
The power supply device including the precharge circuit includes an AC power supply 6, a capacitor 2 charged by the AC power supply 6, a switch 3 and a rectifying unit 11 inserted between the AC power supply 6 and the capacitor 2, a battery 12, and the like. And a charging unit 5 inserted between the battery 12 and the capacitor 2.

The rectification unit 11 is configured by bridge-connecting

diodes

The charging unit 5 includes a transformer 13, an n-channel MOSFET 14, and a diode 15. The positive terminal of the battery 12 is connected to one end of the primary winding of the transformer 13 (hereinafter, the winding start is referred to as “one end”), the negative terminal of the battery 12 is connected to the source of the MOSFET 14, and the transformer 13 is connected to the drain. The other end of the primary winding (hereinafter, the winding end of the winding is referred to as “the other end”) is connected. A series circuit of the secondary winding of the transformer 13 and the diode 15 is connected to the capacitor 2. The anode of the diode 15 is connected to the other end of the secondary winding of the transformer 13.

(Operation of Example 4)
In the precharge circuit according to the fourth embodiment configured as described above, the charging unit 5 charges the capacitor 2 to the peak voltage of the AC power supply 6 or more, and then the switch 3 is turned on so that the inrush current does not flow.

The charging unit 5 includes a transformer 13, a MOSFET 14, and a diode 15, and is configured as an isolated flyback converter. The MOSFET 14 is controlled to be turned on and off by a control means (not shown), and energy input from the battery 12 is stored in the transformer 13 when the MOSFET 14 is turned on. When the MOSFET 14 is turned off, the energy stored in the transformer 13 is released to the capacitor 2 via the diode 15. As a result, energy is transferred from the battery 12 to the capacitor 2, and the capacitor 2 is charged to a voltage higher than the peak voltage of the AC power supply 6.

If a control means (not shown) is configured so as to stop the on / off of the MOSFET 14 when the voltage of the capacitor 2 reaches a predetermined voltage, the loss of the charging unit 5 in the steady state is eliminated, which is more desirable.

(Effect of Example 4)
Since the inrush current limiting resistor can be eliminated, and the charging unit 5 can be made smaller by reducing the charging current, it is possible to reduce the size of the power supply device including the precharge circuit as a whole.
[Example 5]

(Configuration of Example 5)
FIG. 5 is a circuit diagram showing a power supply device including a precharge circuit according to the fifth embodiment of the present invention.
The power supply device including the precharge circuit includes an AC power supply 6, a capacitor 2 charged by the AC power supply 6, a switch 3 and a rectifying unit 11 inserted between the AC power supply 6 and the capacitor 2, a battery 12, and the like. And a charging unit 5 inserted between the battery 12 and the capacitor 2.

The rectification unit 11 is configured by bridge-connecting

diodes

7, 8, 9, and 10. The AC terminal is connected to a series circuit of the AC power source 6 and the switch 3, and the DC terminal is connected to the capacitor 2.

The charging unit 5 includes a transformer 13, an n-channel MOSFET 14, and a diode 15. The positive terminal of the battery 12 is connected to one end of the primary winding of the transformer 13, the negative terminal of the battery 12 is connected to the source of the MOSFET 14, and the other end of the primary winding of the transformer 13 is connected to the drain. A series circuit of the secondary winding of the transformer 13 and the diode 15 is connected to the capacitor 2. The anode of the diode 15 is connected to the other end of the secondary winding of the transformer 13.

The switch 3 is built in the power supply device 16, components other than the AC power source 6, the switch 3, and the battery 12 are built in the charger 18, and the battery 12 and the charger 18 are built in the automobile 17.

(Operation of Example 5)
In the power supply apparatus having the precharge circuit according to the fifth embodiment configured as described above, an inrush current flows by turning on the switch 3 after charging the capacitor 2 to be equal to or higher than the peak voltage of the AC power supply 6 by the charging unit 5. Disappear.

For example, a charging system for charging a high voltage battery of an electric vehicle includes a commercial AC power source 6, a power supply device 16, and a charger 18, and a 12 V low voltage battery 12 is connected to the charger 18. When the switch 3 for disconnecting the commercial AC power supply 6 is built in the power supply device 16, the precharge circuit of the present invention has an advantage that it is not necessary to incorporate the switch 3 for disconnecting the commercial AC power supply 6 in the charger 18. Arise.

Since the conventional precharge circuit is configured to insert an inrush current limiting resistor between the commercial AC power supply 6 and the capacitor 2, it is necessary to connect a switch to a position where the resistor is short-circuited. Therefore, the switch 3 existing regardless of the inrush current limiting resistor cannot be used as a part of the precharge circuit. Therefore, it is necessary to incorporate a parallel circuit of an inrush current limiting resistor and a switch in the charger.

However, since the precharge circuit of the present invention does not have such a restriction, the switch 3 built in the power supply device 16 can be used as a part of the precharge circuit. As a result, it is possible to delete not only the inrush current limiting resistor but also a switch for disconnecting the commercial AC power supply, and further reduce the size of the power supply device including the precharge circuit.

In the precharge circuit of the present invention, it is necessary to turn on the switch 3 after charging the capacitor 2 by the charging unit 5. This may be achieved by providing a communication unit between the automobile 17 and the power supply device 16 and charging the capacitor 2 with the charging unit 5 and then sending information for permitting the switch 3 to be turned on.

(Effect of Example 5)
The inrush current limiting resistor can be deleted, the switch for disconnecting the commercial AC power supply can be deleted, and the charging unit 5 can be reduced by reducing the charging current, thereby reducing the size of the power supply device including the precharge circuit as a whole. Things will be possible.
[Example 6]

(Configuration of Example 6)
FIG. 6 is a circuit diagram showing a power supply device including a precharge circuit in Embodiment 6 of the present invention.
The power supply device including the precharge circuit includes an AC power supply 6, a capacitor 2 charged by the AC power supply 6, a switch 3 and a converter 32 inserted between the AC power supply 6 and the capacitor 2, a battery 12, And a charging unit 5 inserted between the battery 12 and the capacitor 2.

The converter 32 includes a choke 19,

diodes

20, 21, 22, 23,

capacitors

24, 25, and n-

channel MOSFETs

26, 27, 28, 29. A series circuit in which the

diodes

20 and 21 and the

MOSFETs

26 and 27 are connected in this order is connected to the capacitor 2, and the anode of the diode 21 is connected to the drain of the MOSEFT 26. A series circuit in which the

diodes

22 and 23 and the

MOSFETs

28 and 29 are connected in this order is connected to the capacitor 2, and the anode of the diode 23 is connected to the drain of the MOSEFT 28.

The capacitor 24 is connected to the series circuit of the diode 21 and the MOSFET 26, and the capacitor 25 is connected to the series circuit of the diode 23 and the MOSFET 28. One end of the choke 19 is connected to the connection point of the diode 21 and the MOSFET 26, and the other end of the choke 19, the connection point of the diode 23 and the MOSFET 28 is connected to the series circuit of the AC power supply 6 and the switch 3.

The charging unit 5 includes a transformer 13, an n-channel MOSFET 14, and

diodes

15, 30, and 31. The positive terminal of the battery 12 is connected to one end of the primary winding of the transformer 13, the negative terminal of the battery 12 is connected to the source of the MOSFET 14, and the other end of the primary winding of the transformer 13 is connected to the drain. A series circuit of the secondary winding and tertiary winding of the transformer 13 and the diode 15 is connected to the capacitor 2, and a series circuit of the secondary winding of the transformer 13 and the diode 30 is connected to the series circuit of the MOSFET 27 and the capacitor 24. The series circuit of the 13 secondary windings and the diode 31 is connected to the series circuit of the MOSFET 29 and the capacitor 25. The anode of the diode 15 is connected to the other end of the tertiary winding of the transformer 13, and the anodes of the

diodes

30 and 31 are connected to the other end of the secondary winding.
Here, it is assumed that the number of turns of the secondary winding and the tertiary winding of the transformer 13 is equal.

(Operation of Example 6)
In the power supply apparatus having the precharge circuit according to the sixth embodiment configured as described above, an inrush current flows by turning on the switch 3 after charging the capacitor 2 to the peak voltage of the AC power supply 6 by the charging unit 5. Disappear.

Further, the

MOSFETs

27 and 29 are turned on by control means (not shown), the capacitor 2 and the

capacitors

24 and 25 are simultaneously charged by the charging unit 5, and the

capacitors

24 and 25 are charged to a voltage half that of the capacitor 2. 21, 22, 23,

MOSFETs

26, 27, 28, 29 are not applied with a voltage more than ½ of the capacitor 2 voltage.

In Example 6, the

capacitors

24 and 25 are charged to a voltage half that of the capacitor 2 by equalizing the number of turns of the secondary winding and the tertiary winding of the transformer 13. Moreover, the capacitor 2 and the

capacitors

24 and 25 are charged at the same time by configuring the charging unit 5 with one transformer. Therefore, the voltage waveform when the capacitor 2 and the

capacitors

24 and 25 are precharged is as shown in FIG. 7. The difference between the voltage of the

capacitors

24 and 25 and the voltage of the capacitor 2 and the

capacitors

24 and 25 is 1 Never exceed the voltage of / 2. Therefore, the

diodes

20, 21, 22, 23 and the

MOSFETs

26, 27, 28, 29 are not subjected to a voltage more than 1/2 of the capacitor 2 voltage.

(Effect of Example 6)
Since the inrush current limiting resistor can be eliminated, and the charging unit 5 can be made smaller by reducing the charging current, it is possible to reduce the size of the power supply device including the precharge circuit as a whole.
Furthermore, since a low breakdown voltage element can be used as the main circuit element of the multilevel converter, the loss can be reduced, and the main circuit part can be downsized.
[Example 7]

(Configuration of Example 7)
FIG. 8 is a circuit diagram showing a power supply device including a precharge circuit according to the seventh embodiment of the present invention.

A power supply device having a precharge circuit according to a seventh aspect of the present invention includes a capacitor 2 charged by an AC power supply (not shown), a converter 47 connected to the capacitor 2, a battery 12, and the battery 12 and the capacitor. 2 and a charging unit 5 inserted between the two.

The converter 47 includes

capacitors

33, 34, 45,

diodes

35, 36, 42, 43, n-

channel MOSFETs

37, 38, 39, 40, a transformer 41, and a choke 44. A series circuit of

capacitors

33 and 34 is connected to the capacitor 2. A series circuit in which the

MOSFETs

37, 38, 39, and 40 are connected in this order is connected to the capacitor 2. The anode of the diode 35 is connected to the connection point of the

capacitors

33 and 34, and the cathode is connected to the connection point of the

MOSFETs

37 and 38. Yes. The cathode of the diode 36 is connected to the connection point of the

capacitors

33 and 34, and the anode is connected to the connection point of the

MOSFETs

capacitors

33 and 34 and the connection point of the

MOSFETs

38 and 39. The series circuit of the secondary winding of the transformer 41 and the diode 42 is connected to the series circuit of the tertiary winding of the transformer 41 and the diode 43, and the series circuit of the choke 44 and the capacitor 45 is connected to the secondary winding of the transformer 41 and the diode 42. Connected to a series circuit. The anode of the diode 42 is connected to the secondary winding of the transformer 13, and the anode of the diode 43 is connected to the tertiary winding of the transformer 13.

The charging unit 5 includes a transformer 13, an n-channel MOSFET 14, and

diodes

15 and 30. The positive terminal of the battery 12 is connected to one end of the primary winding of the transformer 13, the negative terminal of the battery 12 is connected to the source of the MOSFET 14, and the other end of the primary winding of the transformer 13 is connected to the drain. A series circuit of the secondary winding and tertiary winding of the transformer 13 and the diode 15 is connected to the capacitor 2, and a series circuit of the secondary winding of the transformer 13 and the diode 30 is connected to a series circuit of the diode 36 and the MOSFET 40. . The anode of the diode 15 is connected to the other end of the tertiary winding of the transformer 13, and the anode of the diode 30 is connected to the other end of the secondary winding.
Here, it is assumed that the number of turns of the secondary winding and the tertiary winding of the transformer 13 is equal.

(Operation of Example 7)
In the power supply device including the precharge circuit according to the seventh embodiment configured as described above, the charging unit 5 charges the capacitor 2 and the

capacitors

33 and 34 at the same time, and the

capacitors

33 and 34 are half the voltage of the capacitor 2. As a result, the

MOSFETs

37, 38, 39, and 40 are not charged with voltage more than ½ of the capacitor 2 voltage.

In Example 7, the

capacitors

33 and 34 are charged to a voltage half that of the capacitor 2 by equalizing the number of turns of the secondary winding and the tertiary winding of the transformer 13. Moreover, the capacitor 2 and the

capacitors

33 and 34 are charged simultaneously by forming the charging unit 5 with one transformer. Accordingly, the voltage waveform when the capacitor 2 and the

capacitors

33 and 34 are precharged is as shown in FIG. 7, and the voltage of the

capacitors

33 and 34 does not exceed a voltage half that of the capacitor 2. Therefore, a voltage more than 1/2 of the capacitor 2 voltage is not applied to the

MOSFETs

37, 38, 39, and 40.

Although the circuit in which the

capacitors

33 and 34 are provided in addition to the capacitor 2 is shown in the seventh embodiment, the series circuit constituted by the

capacitors

33 and 34 is obtained by making the capacitance of the

capacitors

33 and 34 twice that of the capacitor 2. It is also possible to eliminate the capacitor 2 by making the capacitance of the capacitor 2 equal to that of the capacitor 2.
Even in this case, the voltage waveform when the

capacitors

33 and 34 are precharged is not different from that of the seventh embodiment, and therefore, the same effect as that of the seventh embodiment is obtained.

In the seventh embodiment, there are two

capacitors

33 and 34 that are connected to the capacitor 2 and form a series circuit. However, the number of

capacitors

33 and 34 that directly form a circuit is not limited to two, and three or more capacitors may be used. good.

(Effect of Example 7)
Since a low breakdown voltage element can be used as the main circuit element of the multilevel converter, the loss can be reduced and the main circuit part can be downsized.

Since the present invention is effective when an inrush current flows through the capacitor 2 by the input power supply 1, the connection form of the input power supply 1 and the capacitor 2 is limited to the form illustrated in FIGS. is not.

Further, since the present invention is effective when the capacitor 2 and the multilevel converter are connected, the embodiment of the multilevel converter is not limited to the forms illustrated in FIGS. 6 and 8. For example, a multi-level converter has the same effect at 4 levels or 5 levels instead of 3 levels.

The flyback converter is also exemplified for the charging unit 5, but is not limited to this form. Even if it is a converter of another circuit system or a plurality of converters are connected in multiple stages, the same effect can be obtained as long as the capacitor 2 can be charged.

The present invention can be applied to a circuit for charging a capacitor in advance.

DESCRIPTION OF SYMBOLS 1 Input power supply 2 Capacitor 3 Switch 4 Input power supply 5 Charging part 6 AC power supply 7 Diode 8 Diode 9 Diode 10 Diode 11 Rectification part 12 Battery 13 Transformer 14 MOSFET
DESCRIPTION OF SYMBOLS 15 Diode 16 Power supply apparatus 17 Car 18 Charger 19 Choke 20 Diode 21 Diode 22 Diode 23 Diode 24 Capacitor 25 Capacitor 26 Capacitor 26 MOSFET
27 MOSFET
28 MOSFET
29 MOSFET
30 diode 31 diode 32 multi-level converter 33 capacitor 34 capacitor 35 diode 36 diode 37 MOSFET
38 MOSFET
39 MOSFET
40 MOSFET
41 Transformer 42 Diode 43 Diode 44 Choke 45 Capacitor 46 Resistance 47 Converter 48 Load device

Claims

A first input power source;
A capacitor charged by the first input power source;
A switch inserted between the first input power source and the capacitor;
A second input power source;
A charging unit inserted between the second input power source and the capacitor;
A precharge circuit.
The precharge circuit according to claim 1, wherein the switch is turned on after the capacitor is charged by the charging unit.
The precharge circuit according to claim 1 or 2, wherein the first input power supply is an AC power supply, and a rectifier is inserted between the first input power supply and the capacitor.
The precharge circuit according to claim 3, wherein the first input power source is a commercial AC power source.
The precharge circuit according to any one of claims 1 to 4, wherein the second input power source is a battery.
The precharge circuit according to any one of claims 1 to 5, wherein the charging unit is an insulating converter.
The precharge circuit according to any one of claims 1 to 6, wherein the charging function of the charging unit is stopped after charging the capacitor.
The capacitor is mounted on a vehicle, the switch is mounted on a power supply device, a communication unit is provided between the vehicle and the power supply device, and information for permitting the switch to be turned on is transmitted from the vehicle to the communication unit. The precharge circuit according to claim 1, wherein the precharge circuit transmits the power to the power supply apparatus through the precharge circuit.
The precharge circuit according to any one of claims 1 to 8, wherein a flying capacitor type multi-level converter is connected to the capacitor, and the charging unit charges the flying capacitor of the multi-level converter simultaneously with the capacitor.
The precharge according to any one of claims 1 to 9, wherein a series circuit in which a plurality of capacitors are connected in series is connected to the capacitor, and the charging unit charges each capacitor of the series circuit simultaneously with the capacitor. circuit.
The precharge circuit according to claim 10, wherein the capacitance of the capacitor is allocated to each of the plurality of capacitors, and the capacitor is deleted.