JP2003018841A - Three-phase input method to power unit, and power unit used therefor and power module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To materialize the balancing of a phase current in a three-phase AC power source at low cost in the case of operating a plurality of power units in parallel by the three-phase AC power source. SOLUTION: Each power unit has a balance current input-output part (b) which inputs and outputs a balance current for taking the balance of an output current of each power unit with each other's AC input terminals not connected and with each other's DC output terminals connected in parallel; and a current balancer 11 which receives the input of the balance current inputted from the balance current input-output part and a detection current corresponding to its own output current and performs the output action for balancing its own output current with the above balance current from the above balance current and the above detection current. The balancer 11 balances each-phase current of the three-phase AC power source by the balancing action of the output current of each power unit by the current balancing part, when the interline voltage from the three-phase AC power source 3 is applied between the AC input terminals of each power unit in order of phases.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-phase input method for a power supply device, a power supply device used for the same, and a power supply module.

[0002]

2. Description of the Related Art The present inventors have filed Japanese Patent Application No. 2000-3046.
No. 02 proposes a power supply module in which a plurality of power supply devices can be connected in parallel to each other on a din rail and a plurality of power supply devices can be combined in an increasing or decreasing manner to obtain an arbitrary power supply capacity. This power supply device includes at least a pair of single-phase AC input type AC input units and a pair of DC output units.

In such a power supply module, even if each power supply device is a single-phase AC input method, each power supply device is operated by a three-phase AC power supply depending on the method of use or the place where it is installed. May be required.

[0004]

In such a case, it is preferable to balance the phase currents of the three-phase AC power supply in order to avoid a burden on the transformer on the three-phase AC power supply side. Therefore, the present inventors have earnestly studied the means for balancing such phase currents.

However, the conventional phase current balancing means such as a transformer with a balance function, a power supply device of a three-phase input type, and a load for each phase are evenly connected to each other inevitably increase the cost or reduce the number of installation steps. Leads to an increase.

Therefore, according to the present invention, when a plurality of power supply devices of the single-phase AC input system are operated in parallel using a three-phase AC power supply, the balance of the phase currents of the three-phase AC power supply is reduced. The problem to be solved is to make it feasible at a cost.

[0007]

(1) A three-phase input method for a power supply unit according to the present invention converts an AC input terminal and a single-phase AC voltage input from the AC input terminal into a DC voltage and outputs the DC voltage. A three-phase input method for a plurality of single-phase AC input type power supply devices including a power supply circuit and a DC output terminal for outputting the output of the power supply circuit, wherein AC input terminals of the respective power supply devices are not connected. And connecting the respective DC output terminals in parallel, applying a line voltage or a phase voltage from a three-phase AC power supply to the AC input terminals of the respective power supply devices, and between the output currents of the respective power supply devices. By balancing, the phase currents of the three-phase AC power supply are balanced.

Here, the three-phase AC power supply may be commercial or non-commercial. The three-phase AC power supply may have a star-type connection between the phases or a Δ-type connection. The three-phase AC power supply may be symmetrical or asymmetrical.

According to the present invention, the current balancing unit balances the phase currents of the three-phase AC power source, so that the transformer with the balancing function, the three-phase input type power supply device, and the loads of the respective phases are equalized. It is possible to avoid a burden on the transformer on the side of the three-phase AC power source without using a phase current balancing means that results in an increase in cost such as connection and an increase in the number of installation steps.

(2) In the power supply device of the present invention, a pair of AC input terminals, a power supply circuit for converting a single-phase AC voltage input from the both AC input terminals into a DC voltage and outputting the DC voltage, and a power supply circuit for the power supply circuit. A pair of direct current output terminals for outputting an output, and both the alternating current input terminals are non-connectable to an alternating current input terminal provided in another power supply device, and the both direct current output terminals are other power supply devices A power supply device that can be connected in parallel to a DC output terminal provided in, the self-AC input terminal is not connected to the AC input terminal of another power supply device and its own DC output terminal is other A balance for connecting the output currents of the other power supply units in series while being connected in parallel to the DC output terminals of the power supply unit and connected in series to the balance current input / output unit of the other power supply unit. Turn on the electric current Inputting the balance current input / output section that applies the input current, the balance current input from the balance current input / output section, and the detection current corresponding to the self output current, and the self output current is calculated from the balance current and the detection current. A current balance unit that performs an output operation for balancing the balance current, is connected in parallel with the other power supply device, and has a line voltage or a phase voltage from a three-phase AC power supply to its own AC input terminal. Is applied, the respective phase currents of the three-phase AC power source are balanced by the action of balancing the output currents of the respective power supply devices by the current balancing unit of its own.

According to the present invention, the current balancing unit balances the phase currents of the three-phase AC power supply, so that the transformer with the balance function, the power supply device of the three-phase input system, and the load of each phase are equalized. It is possible to avoid a burden on the transformer on the side of the three-phase AC power source without using a phase current balancing means that results in an increase in cost such as connection and an increase in the number of installation steps.

(3) The power supply module of the present invention has a plurality of single-phase AC input type power supply devices, and each power supply device is input from a pair of AC input terminals and both of the AC input terminals. A power supply circuit that converts a single-phase AC voltage into a DC voltage and outputs the power supply circuit; and a pair of DC output terminals that outputs the output of the power supply circuit, and the mutual DC output terminals can be connected in parallel. Power supply module,
The respective power supply devices are connected in parallel with each other in a state where their AC input terminals are not connected and their DC output terminals are connected in parallel to balance the output currents of the other power supply devices. A balance current input / output unit for inputting / outputting a balance current, and a balance current input from the balance current input / output unit and a detection current corresponding to its own output current are input, and from the balance current and the detection current, It has a current balance section that performs an output operation for balancing its own output current to the balance current,
When a line voltage or a phase voltage from a three-phase AC power supply is applied between the pair of AC input terminals of each of the power supply devices, by the action of balancing the output current between the power supply devices by the current balance unit, The phase currents of the three-phase AC power supply are balanced.

According to the present invention, the current balancing unit balances the phase currents of the three-phase AC power supply, so that the transformer with the balance function, the power supply device of the three-phase input system, and the load of each phase are equalized. It is possible to avoid a burden on the transformer on the side of the three-phase AC power source without using a phase current balancing means that results in an increase in cost such as connection and an increase in the number of installation steps.

[0014]

DETAILED DESCRIPTION OF THE INVENTION The details of the present invention will be described below with reference to the embodiments shown in the drawings.

The power supply device in this embodiment is
It will be explained by applying it to a relatively small switching power supply.
The present invention is not limited to this switching power supply.

1 to 4 relate to an embodiment of the present invention, and FIG. 1 is a view showing a power supply module constructed by mounting a plurality of power supply devices on a DIN rail, and FIG.
FIG. 4 is a diagram showing an electrical connection relationship of each power supply device in the power supply module, FIG. 3 is a circuit diagram of the power supply device, and FIG. 4 is a circuit diagram of a main part of the power supply device.

With reference to these figures, 1 is a din rail, and 21, 22 and 23 are first to third power supply devices of a single-phase AC input system. These power supply devices 21, 22, 2
A power supply module is constituted by 3.

Each power supply device 2 in the power supply module
1, 22, 23 are movably mounted on the din rail 1.

In each of the power supply devices 2, 21a,
21b; 22a, 22b; 23a, 23b are AC input terminals, 21c, 21d; 22c, 22d; 23c, 23.
d is a DC output terminal, and 21e, 22e, and 23e are power supply circuits.

21f, 21g; 22f, 22g; 23
f and 23g are AC connectors, 21h and 21i; 22
h, 22i; 23h and 23i are DC connectors, 21
j, 21k; 22j, 22k; 23j, 23k are current balance connectors.

Each of the power supply devices 21, 22, and 23 has a rectangular parallelepiped casing in which required power supply circuit components are built in, for example, 100 to 240 VAC input, 24 VDC output, 2.5.
A, a switching power supply for 60 W output.

Reference numeral 3 is a three-phase AC power supply, and the three-phase AC power supply 3 has three single-phase power supplies P1, P2 and P3 connected in a star shape. The first single-phase power supply P1 receives the first-phase current i1, the second single-phase power supply P2 receives the second-phase current i2, and the third single-phase power supply P3 receives the third-phase current i3. Flowing.

In the first power supply device 21, a line current i11 flows through one AC input terminal 21a and a line current i12 flows through the other AC input terminal 21b. In the second power supply device 22, the line current i21 is supplied to one AC input terminal 22a, and the line current i2 is supplied to the other AC input terminal 22b.
2 flows. In the third power supply device 23, the line current i31 flows through the one AC input terminal 23a, and the line current i32 flows through the other AC input terminal 23b.

In each of the power supply devices 21, 22, 23, AC input terminals 21a, 21b; 22a, 22
b; 23a and 23b are arranged on the upper part of the front panel to supply the external commercial alternating current of 100 to 240 VAC to the power supply circuit 21.
e, 22e, 23e, and the respective DC output terminals 21c, 21d; 22c, 22d; 23c, 2
3d is arranged in the lower part of the front panel and outputs 24VDC.

The power supply circuits 21e, 22e and 23e have AC input terminals 21a and 21b; 22a and 22b; 23a and 2 respectively.
DC input terminal 21c, which converts the AC input from the outside via 3b to a stabilized 24VDC output,
21d; 22c, 22d; 23c, 23d, and outputs to the outside. In this embodiment, it is a power supply circuit such as an insulating switching regulator.

DC output terminals 21c, 21d; 22c, 2
2d; 23c and 23d are a pair of plus and minus.

AC connector 21f in the first power supply device 21
And 21g between the AC connector 2 in the second power supply 22
2f and 22g, between AC connectors 23f and 23g in the third power supply device 23, between DC connectors 21h and 21i in the first power supply device 21, and DC connector 22h in the second power supply device 22. 22i, between the DC connectors 23h and 23i in the third power supply device 23, the first power supply device 2
1 between the current balance connectors 21j and 21k, and the second power supply device 22 within the current balance connectors 22j and 22k.
k and the current balance connectors 23j and 23k in the third power supply device 23 are electrically connected directly to each other through appropriate bus line wiring.

Then, AC connectors 21f, 21g; 22f, 22g; 23 between the respective power supply devices 21, 22, 23.
f and 23g are not connected.

Further, the DC output terminals 21c and 21d; 22c and 22d;
23c and 23d are connected in parallel with each other.

In the above power supply module, the three-phase AC from the three-phase AC power supply 3 input to each of the power supply devices 21, 22, and 23 is the DC output terminal 2 of each power supply device 2.
1c, 21d; 22c, 22d; 23c, 23d are turned into direct current and output.

In this power supply module, the power supply device 21,
When only one of the power supply capacities 22 and 23 cannot handle the load, the power supply capacity can be increased by expanding the other power supply device.

As a result, according to this power supply module,
A power supply manufacturer can provide a user with a power supply having an arbitrary capacity simply by manufacturing a power supply device having the same output voltage. For users, in addition to the low selling price of one power supply unit, purchasing one or more power supply units of the same capacity as compared to purchasing separate power supplies for each capacity, depending on the application Since there is no need for stock for maintenance.

Incidentally, A power supply device may be added so that if one of the power supply devices fails, the additional power supply device can be used as a spare.

Next, the features of this embodiment will be described.

In this description of characteristics, the power supply devices 21, 22, and 23 have the same configuration, and therefore the first power supply device 21 will be described as an example.

In the power supply device 21 shown in FIG. 3, the power supply circuit 21e includes a primary side rectifying / smoothing section 3, a switch element 4, a control section 5, a converter transformer 6, a secondary side rectifying / smoothing section 7, a voltage detecting section 8, It has a backflow prevention diode 9, a current detection unit 10, a current balance unit 11, and a Zener diode 12 as a power cutoff element. Further, the primary side rectifying / smoothing unit 3, the switch element 4, and the converter transformer 6 configure a conversion unit that converts an input voltage into a required output voltage.

The first power supply device 21 having such a configuration
Are connected in parallel with the other power supply devices 22 and 23, and have their own AC input terminals 21a and 21b and the AC input terminals 22 of the other power supply devices 22 and 23, respectively.
The line voltage from the three-phase AC power supply 3 is applied in sequence between the a, 22b and 23a, 23b. Specifically, each single-phase power source P1, P2, P3 that constitutes the three-phase commercial AC power source 3
Assuming that the respective phase voltages are V1, V2 and V3, the line voltage of V1 + V2 is applied to the first power supply device 21, the line voltage of V2 + V3 is applied to the second power supply device 22, and the third power supply device 2 is used.
A line voltage of V3 + V1 is applied to each of the lines 3. Corresponding to these line voltages, each power supply device 21,
A line current, that is, an input current flows through each of 22 and 23.

The input current input between the AC input terminals 21a and 21b of the first power supply device 21 is passed through the primary side rectifying / smoothing section 3 according to the on / off operation of the switching element 4 and the primary of the converter transformer 6 is turned on. Flowing into the coil. As a result, the voltage generated in the primary coil is induced in the secondary coil. This induced voltage is applied to the secondary side rectifying / smoothing unit 7
After being converted into a direct current by, the voltage is output from the direct current output terminals 21c and 21d through the voltage detection unit 8 and the backflow prevention diode 9.

The voltage detector 8 detects the output voltage and feeds it back to the controller 5. Based on this detection, the control unit 5 controls the switching element 4 to turn on and off to control the output voltage to be constant.

In contrast to the basic operation of the power supply circuit 21c, in the present embodiment, the current detection unit 10 and the current balance unit 11 compare the output current of itself and the average output current of another power supply device. . The comparison result is output to the control unit 5. As a result, the first power supply device 21 balances the current with the other power supply devices 22 and 23. On the other hand, when the output voltage drops below a predetermined value, the Zener diode 12 becomes non-conductive to stop the supply of power to the current balance unit 11. This stops the operation of the current balance unit 11.

A more detailed description will be given.

The current balance section 11 includes a non-inverting amplifier 11
1 and a comparison amplifier 112. Non-inverting amplifier 11
The minus input section of 1 is connected to the current detection section 10. This connection point is referred to as a detection current connection point (a). The positive input section of the non-inverting amplifier 111 is grounded via the resistor 113. The output section and the positive input section of the non-inverting amplifier 111 are connected via a resistor 117.

The DC output terminal 21c and the voltage detector 8
A backflow prevention diode 9 is connected between and. The backflow prevention diode 9 has its cathode at the DC output terminal 2
1c, by which the power supply 2
When 1 is operated in parallel with the other power supply devices 22 and 23, the output current is prevented from flowing backward from the other power supply devices 22 and 23 to the power supply device 21.

The minus input portion of the comparison amplifier 112 is connected to the output portion of the non-inverting amplifier 111 via the resistor 114, and the plus input portion thereof is resistors 115 and 116.
Through the output of the non-inverting amplifier 111. The connection part of both resistors 115 and 116 is connected to the current balance side connector 2h via the current balance bus line. This connection point is called a balanced current connection point (b). This serves as a balanced current input / output unit.

The non-inverting amplifier 111 and the comparison amplifier 112 are connected to the power source input sections 111a and 112, respectively.
a and ground portions 111b and 112b, and the power input portions 111a and 112a are connected between the secondary side rectifying / smoothing portion 7 and the voltage detecting portion 8 via a Zener diode 12 as a power cutoff element. Connected to the line. This connection point is referred to as a power supply current connection point (c).

The operation of the current balance section 11 having the above structure will be described.

First, the operation of the current balance section 11 in the first power supply device 21 when the plurality of power supply devices 21, 22, 23 are all normal will be described. Note that the number of parallel power supply devices is, for example, "3".

First, the voltage at the balanced current connection point (b) will be examined. The balanced current connection point (b) corresponds to each power supply device 21,
Since the connection points are common to the current balance sections 22 and 23, the current flowing therethrough is zero according to Kirchhoff's law. Although detailed description is omitted, the voltage V at the balanced current connection point (b) is set to the respective power supply devices 21, 22, 22.
23 Set the voltage at the output of each non-inverting amplifier 111 to V
1, V2, V3, V = (V1 + V2 + V3) / 3
Becomes That is, the voltage at the balanced current connection point (b) is an average voltage.

Since the voltage at the output of the non-inverting amplifier 111 is, in other words, the output current detected by the current detector 10, the voltage at the balance current connection point (b) is, that is, the power supply devices 21 and 22. , 23 respectively corresponding to the average output current.

In the comparison amplifier 112, the output voltage of the non-inverting amplifier 111 is applied to the minus input portion via the resistor 114, and the plus input portion is connected to the balance current connection point (b) via the resistor 116. A voltage is applied. That is, the comparison amplifier 112 compares its own output current with the average output current of each power supply device 2, and the output of the comparison amplifier 112 shows how much its own output current is from the average output current. A comparison signal indicating whether there is a deviation is output.

In response to the comparison signal from the current balance section 11, the control section 5 controls on / off of the switch element 4 so that its own output current balances with the average output current.

Next, when the first power supply device 21 is normal, the zener diode 12 is conducting and the non-inverting amplifier 11
Since 1 is operating, the input impedance (input impedance of the current balance unit 11) viewed from the balanced current connection point (b) is the sum of the output impedance of the non-inverting amplifier 111 and the resistance value of the resistor 115. In this case, the output impedance of the non-inverting amplifier 111 is the resistance 11
It is sufficiently smaller than the sum of both resistance values of 3,117.

When the Zener diode 12 becomes non-conductive due to the output voltage drop due to the failure of the first power supply device 21, the non-inverting amplifier 111 stops operating, resulting in the input impedance ((b) seen from the balanced current connection point (b). The input impedance of the current balance unit 11) is the resistance 113, 1
It is the sum of the resistance values of each of 17 and 115. in this case,
The output impedance of the non-inverting amplifier 111 is 1
It is sufficiently larger than the sum of the resistance values of 13, 117.

That is, the difference between the input impedance when the first power supply device 21 is normal and the input impedance when it is defective is sufficiently smaller than the sum of the resistance values of the resistors 113 and 117, and the output of the non-inverting amplifier 111. The difference is the impedance and the sum of the resistance values of the resistors 113 and 117. Obviously, the input impedance when the first power supply device 21 fails is sufficiently higher.

Therefore, the Zener diode 12 acts as an impedance control unit for controlling the input impedance of the current balancing unit 11 to be high when the state of the first power supply unit 21 is in a predetermined state such as a failure.

As described above, when the output current of the first power supply device 21 is greatly reduced due to a failure of the first power supply device 21, the Zener diode 12 becomes non-conducting and the balanced current connection point.
Since the input impedance of the current balance section 11 seen from (b) is high as described above, the balance current connection point
The average voltage in (b) is not affected.

In this case, if the Zener diode 12 is not provided, since the first power supply device 21 and the other power supply devices 22 and 23 are connected to each other through their DC output terminals, the other power supply devices 21 and 23 are connected. The output current leaks from the side through the backflow prevention diode 9 and is charged in the smoothing capacitor in the secondary side rectifying and smoothing unit 8. Then, this charging power is supplied to the non-inverting amplifier 111 in the current balance section 11 and the power supply input sections 111a and 112a of the comparison amplifier 112, and these non-inverting amplifier 111 and comparison amplifier 112 are supplied.
Becomes the operating state. Then the balance current connection point
The input impedance seen from the current balance section 11 from (b) is low, and the average voltage at the balanced current connection point (b) is low, which adversely affects the current balance in the other normal power supply devices 22 and 23.

However, the non-inverting amplifier 111 and the comparison amplifier 112 both stop operating due to the non-conduction of the Zener diode 12, so that the smoothing capacitor does not supply power, and the balance current connection point.
The input impedance seen from the current balance section 11 from (b) is high, and the current balance in the other normal power supply devices 22 and 23 is not adversely affected.

In this embodiment, each power supply device 2
Since each of 1, 2, 23 and 23 is provided with the current balancing unit 11 having the above-described configuration and operation, the output currents of the respective power supply devices 21, 22, 23 are balanced, so that the input currents thereof are also balanced, Therefore, the phase currents I1, I2, I3 flowing through the single-phase power supplies P1, P2, P3 in the three-phase commercial AC power supply 3 are also balanced.

Therefore, according to the present embodiment, in order to balance the phase currents, a transformer with a balancing function, a three-phase input type power supply device, and a load for each phase are connected equally as in the conventional case. It is no longer necessary to use a phase current balancing means that increases the cost and the number of installation steps, and the burden on the transformer on the three-phase AC power supply side can be avoided.

The present invention is not limited to the above-described embodiment, and various applications and modifications can be considered.

(1) In the above case, the non-inverting amplifier 11
Zener diode 12 for power supply input section 111a
And the Zener diode 12 need not be connected to the comparison amplifier 112.

(2) In the above case, the average output current is used as the balance current for balancing the output current of each of the other power supply devices, and its own output current follows this average output current. To balance the current. The present invention is not limited to this as the balance current, and the maximum output current may be used as the balance current and the output current of its own may be made to follow this to perform the current balance. Alternatively, the output current of the self may be made to follow this and current balance may be performed.

(3) Although the Zener diode 12 is used as the power cutoff element in the above case, the present invention is not limited to this, and a circuit or element having another power cutoff function may be used.

(4) In the above case, the conversion unit is a switch element or a converter transformer in an insulation type switching power supply such as a forward system or a flyback system equipped with a converter transformer. However, the present invention is not limited to the above, but can be applied to, for example, a non-insulated switching power supply using a tap inductor, which uses a tap inductor or a switch element.

(5) In the case of the above-described non-inverting amplifier 111, when the resistor 113 is omitted and the output section and the positive input section are short-circuited to form a buffer amplifier, the Zener diode 12 becomes non-conductive. When the power supply to the current balance unit 11 is cut off, the input impedance of the current balance unit 11 seen from the connection point (b) can be made higher.

(6) In the case of the above power supply module,
The number of connected power supply devices is three, but the number is not limited to this, and the number may be a multiple of three. Of course, the number of connected devices is not particularly limited to a multiple of 3.

(7) The above three-phase AC power supply may or may not be commercial. A three-phase AC power supply has a delta connection even if the phases are connected in a star pattern.
It may be connected in the (Δ) type. The three-phase AC power supply may be symmetrical or asymmetrical.

(8) In the above description, the line voltage is applied to the AC input terminal of the power supply device, but the present invention is not limited to this, and a phase voltage may be applied.

[0070]

As described above, according to the present invention, when a plurality of power supply devices are operated in parallel by a three-phase AC power supply, it is possible to realize a balanced phase current in the three-phase AC power supply at low cost. You can

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a power supply module according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing an electrical configuration of the power supply module of FIG.

3 is a circuit diagram of a power supply device constituting the power supply module of FIG.

FIG. 4 is a circuit diagram of a current balance unit, which is a main part of FIG.

[Explanation of symbols]

1 Din Rail 21,22,23 power supply 3 three-phase AC power supply

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5H410 BB05 CC04 DD02 DD05 EA37                       EB40 FF03 FF05 FF25                 5H730 BB23 CC01 FD31

Claims (3)

[Claims] 1. An AC input terminal, a power supply circuit for converting a single-phase AC voltage input from the AC input terminal into a DC voltage and outputting the DC voltage, and a DC output terminal for outputting the output of the power supply circuit. A three-phase input method for a plurality of single-phase AC input type power supply devices, wherein the AC input terminals of each power supply device are not connected and the respective DC output terminals are connected in parallel, and each power supply device is A line voltage or a phase voltage from a three-phase AC power supply is applied to each AC input terminal to balance the output currents of the power supply devices to balance the phase currents of the three-phase AC power supply. A three-phase input method for a power supply device, comprising: 2. A pair of AC input terminals, a power supply circuit for converting a single-phase AC voltage input from both of the AC input terminals into a DC voltage and outputting the DC voltage, and a pair of DC outputs for outputting the output of the power supply circuit. A terminal, and both of the AC input terminals are non-connectable to an AC input terminal of another power supply device, and the both DC output terminals, with respect to the DC output terminal of the other power supply device A power supply device that can be connected in parallel, wherein the own AC input terminal is not connected to the AC input terminal of another power supply device and its own DC output terminal is parallel to the DC output terminal of another power supply device. Connected to the balance current input / output unit of the other power supply device in series, the balance current input / output for inputting / outputting the balance current for balancing the output currents of the other power supply devices. Inputting a balance current input from the balance current input / output unit and a detection current corresponding to its own output current, and balancing its own output current to the balance current from the balance current and the detection current. And a current balance unit for performing an output operation for causing the output power to be connected in parallel with the other power supply device, and a line voltage or a phase voltage from a three-phase AC power supply is applied to its own AC input terminal. At this time, the power supply device is characterized in that the respective phase currents of the three-phase AC power supply are balanced by the action of balancing the output currents between the power supply devices by the respective current balancing units. 3. A plurality of single-phase AC input type power supply devices, each power supply device having a pair of AC input terminals, respectively.
A power supply circuit for converting a single-phase AC voltage input from both the AC input terminals into a DC voltage and outputting the DC voltage, and a pair of DC output terminals for outputting the output of the power supply circuit, and the mutual DC A power supply module in which output terminals are connectable in parallel, wherein each of the power supply devices is parallel to each other in a state where mutual AC input terminals are not connected and mutual DC output terminals are connected in parallel. A balanced current input / output unit that is connected and inputs / outputs a balanced current for balancing the output currents of other power supply devices, and a balanced current input from the balanced current input / output unit and its own output current And a current balance section that performs an output operation for balancing its own output current to the balance current from the balance current and the detection current. When a line voltage or a phase voltage from a three-phase AC power supply is applied between a pair of AC input terminals of each of the power supply devices, balancing the output current between the power supply devices by the current balance unit. A power supply module, which balances the phase currents of the three-phase AC power supply by the action.