JP3498646B2 - Power supply device and power supply system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power feeding device and a power feeding system.

[0002]

2. Description of the Related Art Conventionally, a plurality of terminals are connected to a transmission control device via a two-wire signal line, and data is transmitted between the transmission control device and the terminals or between the terminals. There is known a data transmission system that makes it possible. In this type of data transmission system, a unique address is set for each terminal and data can be transmitted to a desired terminal by designating each terminal using the address. That is, by including the address together with the data in the transmission signal transmitted through the signal line, the data can be transmitted to the terminal device designated by the address. In this type of data transmission system, the power of the terminal is supplied through a signal line.
Therefore, a power supply device is connected to the signal line in order to supply power to the terminal device through the signal line using the terminal device as a load. That is, the signal line functions as a load line that forms a power supply path to the load. The power feeding device may be provided separately from the transmission control device or may be provided in the transmission control device.

Not only the data transmission system as described above, but also a structure for supplying electric power to the load from the power supply device,
As shown in FIG. 20, a plurality of loads 2 are connected to a two-wire type load line Ls, and the load 2 is connected from the power feeding device 1 through the load line Ls.
The configuration for supplying DC power to the is widely adopted.

The power supply device 1 shown in the figure is configured to apply a substantially constant DC voltage Vo to the load line Ls using the DC power source E as a power source, and the DC-DC converter 11a for converting the DC power source E into a voltage. , 11b. Here, the DC power source E is, for example, a commercial power source rectified and smoothed, and has a sufficiently large current capacity. Further, the DC power source E is connected to the power feeding device 1 via the switch SW. Although a step-down chopper circuit is assumed as the DC-DC converters 11a and 11b, a DC-DC converter circuit having another configuration known as a switching power supply circuit may be used.

By the way, the load 2 connected to the load line Ls
If the power consumption in the power supply becomes large (generally, the power consumption increases when the load 2 is added), the power supplied from the power supply device 1 may become insufficient. Therefore, in the circuit shown in FIG. 20, two DC-DC converters 11a and 11b are provided and both DC-DC converters 11a and 11b are connected in parallel to the load line Ls. If this configuration is adopted, one D
Compared to the case where a large current capacity is secured only by the C-DC converter, it is considered that it is possible to secure a large capacity at a comparatively low cost, since it is not necessary to use a high-capacity expensive component.

However, a plurality of DC-DC converters 11
Since it is difficult to control the output voltages of a and 11b to be the same voltage, the output currents of the DC-DC converters 11a and 11b are not equal, and as a result, either of the DC-DC converters 11a and 11b is output. Output current becomes large, causing imbalance in the output current. Therefore, in the configuration shown in FIG. 20, the output currents of the DC-DC converters 11a and 11b are individually detected by the current detection means 12a and 12b, and the current values detected by the current detection means 12a and 12b become equal. As described above, the control circuit 13 controls both the DC-DC converters 11a and 11b.

[0007]

However, even if the power supply device 1 is provided with a plurality of DC-DC converters 11a and 11b to increase the current capacity, it may not be possible to cope with the increase in the load 2. In such a case, the power supply device 1 of another specification having a required current capacity according to the power consumption of the load 2 is required, and the power supply device 1 is made into a variety of products, and manufacturing cost, management cost, There is a problem that it leads to an increase in inventory costs. On the contrary, when the current capacity of the power supply apparatus 1 is excessive with respect to the load 2, the power supply apparatus 1 of another specification is required, and in this case, the same problem as when the current capacity of the power supply apparatus 1 is insufficient is also caused. Occurs. In short, the power supply device 1 does not have flexible expandability that can cope with an excess or deficiency in the current capacity.

Further, since only one power supply device 1 is connected to the load line Ls, if the power supply device 1 fails, power cannot be supplied to the load 2 and system reliability is improved. Currently, it cannot be said that the maintainability is sufficiently high.

The present invention has been made in view of the above circumstances, and an object thereof is to enable the number of connected load lines to be arbitrarily increased or decreased to enhance expandability, reliability, and maintainability, and further, to improve output current. To provide a power supply device and a power supply system capable of easily responding to an excess or deficiency of current capacity by saving wiring by simply connecting to a load line without separately providing a control means for equalizing power consumption. It is in.

[0010]

According to a first aspect of the present invention, there is provided a direct current power supply section for changing an output voltage according to a separately input control signal, and an output voltage detection section for detecting an output voltage of the direct current power supply section. An output voltage range setting unit that sets a voltage range of the output voltage as an output voltage range; and a range in which the output voltage is less than a lower limit value of the output voltage range, the larger the difference between the output voltage and the lower limit value is, And a voltage control section for giving to the DC power supply section a control signal generated to increase the output voltage and having a maximum value regulated.

According to a second aspect of the present invention, a DC power supply unit that changes the output voltage according to a separately input control signal, an output voltage detection unit that detects the output voltage of the DC power supply unit, and a voltage of the output voltage. An output voltage range setting unit that sets a range as an output voltage range, and outputs a control voltage that increases as the difference between the output voltage and the lower limit value increases in a range in which the output voltage is less than the lower limit value of the output voltage range. Output voltage range determination means for setting the control voltage to a zero voltage in a range that is equal to or higher than the lower limit value of the output voltage range, and a reference voltage that generates a reference voltage that is higher as the control voltage is higher and whose maximum value is restricted. A setting circuit and a control circuit for giving to the DC power supply unit a control signal generated so as to increase the output voltage of the DC power supply unit as the reference voltage increases.

According to a third aspect of the present invention, in the second aspect of the present invention, the reference voltage is generated by adding a variable reference voltage that changes according to the control voltage to a preset fixed reference voltage.

According to another aspect of the present invention, there is provided a DC power supply section for changing an output voltage according to a separately input control signal, an output voltage detecting section for detecting an output voltage of the DC power supply section, and a voltage of the output voltage. An output voltage range setting unit that sets a range as an output voltage range, and outputs a control voltage that increases as the difference between the output voltage and the lower limit value increases in a range in which the output voltage is less than the lower limit value of the output voltage range. Output voltage range determination means for setting the control voltage to zero in a range that is equal to or higher than the lower limit value of the output voltage range, and a feedback gain that increases as the control voltage increases and whose maximum value is regulated A feedback gain setting circuit that error-amplifies an error voltage between a voltage and a specified feedback reference voltage to generate a reference voltage; In which a control circuit for applying the generated control signal so as to increase the pressure to the DC power supply unit.

According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, the DC power supply unit is a switching power supply circuit, and the ON / OFF ratio of a switching element forming the DC power supply unit is controlled as the control signal. The time ratio signal is used.

According to a sixth aspect of the present invention, in the first to fifth aspects of the present invention, an output current detecting section for detecting the output current of the DC power source section and a constant current for setting a limit value of the output current that can be supplied. A value setting unit and an output current determination unit that limits a control signal output from the control circuit so that the output current does not exceed the limit value.

According to a seventh aspect of the present invention, in a power feeding system including a plurality of power feeding devices connected in parallel to a set of load lines to which a load serving as a load is connected, each power feeding device is characterized by
7. A power supply device according to claim 6, further comprising: current detection means for detecting an output current when the line voltage of the load line reaches an output voltage range which is a voltage range required to operate the load; A power supply device, which further includes a transmission unit that transmits information between the devices via the load line, and a control unit that controls the output current detected by the current detection unit to have a current value assigned thereto. Any one of the power supply devices includes a current distribution unit that calculates a sum of current values of output currents transmitted from the power supply devices through the transmission unit and distributes and allocates the current value according to the current capacity of each power supply unit. The current value assigned to another power feeding device is notified to another power feeding terminal by the transmission means.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) Power Supply Device 1
Is connected to the load line Ls to which the load 2 is connected as shown in FIG. 5, and supplies electric power to the load 2. Further, a plurality of power supply devices 1 described below can be connected to the load line Ls. That is, the output terminal of each power feeding device 1 can be commonly connected to a pair of two-wire type load lines Ls, and the power feeding device 1 is connected in parallel to the load line Ls. Hereinafter, a state in which power is supplied to the load 2 from a plurality of power supply devices 1 connected in parallel to the load line Ls is referred to as parallel power supply.

The power supply device 1 of the present embodiment has the configuration shown in FIG. 1 and has a function of supplying electric power to the load 2 via the load line Ls. The output voltage from the power feeding device 1 is a DC voltage, and the DC power source E is used as the power source of the power feeding device 1.
As the DC power source E, a power source obtained by rectifying and smoothing a commercial power source is usually used as in the conventional configuration. Therefore, the power supply device 1 is provided with the DC-DC converter 11 that generates a DC voltage to be supplied to the load 2 by using the DC power supply E as a power source. In the present embodiment, it is assumed that a step-down (buck) type chopper circuit is used as the DC-DC converter 11, but a step-up (boost) type chopper circuit, a polarity inversion (back / boost) type chopper circuit, a flyback. Other types of switching power supply circuits such as circuits may be used.

The output voltage of the DC-DC converter 11 is DC
This can be controlled by changing the on / off ratio (hereinafter, referred to as duty ratio) of the switching element which is a constituent element of the −DC converter 11. That is, DC-DC
A duty ratio signal D for determining a duty ratio is given to the conversion unit 11 as a control signal from the control circuit 10 which will be described later, and the duty ratio signal D controls the output voltage of the DC-DC conversion unit 11. Here, the output voltage is not controlled inside the DC-DC converter 11, and the output voltage of the DC-DC converter is controlled only by the duty ratio signal D from the control circuit 10.

The output voltage Vo of the DC-DC converter 11, that is, the line voltage of the load line Ls is detected by the output voltage detector 14. The line voltage of the load line Ls detected by the output voltage detection unit 14 (that is, the output voltage Vo of the DC-DC conversion unit 11) is input to the output voltage range determination unit 15,
The output voltage range V set by the output voltage range setting unit 16 as the range of the line voltage required for the load 2 to operate normally
The magnitude of s is compared. That is, the output voltage range setting unit 16 can adjust the output voltage range Vs. The output voltage detection unit 14 is actually the DC-DC conversion unit 1.
Although the output voltage Vo of 1 is divided, the output voltage of the output voltage detector 14 is proportional to the output voltage Vo of the DC-DC converter 11, and thus the output voltage detector 1
The output voltage of No. 4 is treated as the output voltage Vo of the DC-DC converter 11.

The output voltage range Vs has a predetermined width in which an upper limit value and a lower limit value are set, and the output voltage range determination means 15 outputs the output voltage of the DC-DC converter 11 as shown in FIG. In a range where Vo is less than the lower limit value of the output voltage range Vs, the control voltage Vd that increases in proportion to the difference between the output voltage Vo of the DC-DC converter 11 and the lower limit value is output. Also,
In the range that is equal to or higher than the lower limit value of the output voltage range Vs, DC-
Regardless of the output voltage Vo of the DC converter 11, the control voltage V
The voltage d is set to 0V (zero voltage). Further, the output voltage range determination means 15 gives an instruction to the control circuit 10 to stop the operation of the DC-DC converter 11 when the output voltage Vo is higher than the upper limit value of the output voltage range Vs.

The control voltage Vd is input to the converter 17a in the reference voltage setting circuit 17, and the converter 17a in FIG.
As shown in (b), a variable reference voltage Vref2 that increases in proportion to the control voltage Vd is generated. However, the variable reference voltage V
A maximum value is set for ref2, and the variable reference voltage Vref2 is kept at the maximum value when the control voltage Vd is equal to or higher than a predetermined value. This maximum value regulates the maximum value of the output voltage Vo of the DC-DC converter 11. Variable reference voltage Vr
ef2 is a preset fixed reference voltage Vr
ef1 is added to the reference voltage Vref (= Vref1 + V
ref2) is generated. The reference voltage Vref is input to the control circuit 10, and the duty ratio signal D having a duty ratio (duty ratio) according to the reference voltage Vref is sent to the control circuit 10.
To the DC-DC converter 11.

The relationship between the duty ratio signal D and the reference voltage Vref is as shown in FIG. 2C, and the duty ratio of the duty ratio signal D increases as the reference voltage Vref increases. The duty ratio defines the minimum value when the reference voltage Vref is 0V, and even when the reference voltage Vref is 0V, the duty ratio signal D having a predetermined duty ratio is output. As described above, the reference voltage Vre
f becomes higher as the control voltage Vd becomes higher, and the control voltage Vd becomes the output voltage range V of the output voltage Vo of the DC-DC converter 11.
When it is lower than the lower limit value of s, it increases in proportion to the difference between the output voltage Vo and the lower limit value. Therefore, the duty ratio of the duty ratio signal D is the output voltage V in the range in which the output voltage Vo of the DC-DC converter 11 is lower than the lower limit value of the output voltage range Vs.
When the output voltage Vo is within the output voltage range Vs, the duty ratio of the duty ratio signal D becomes constant regardless of the output voltage Vo.
When exceeds the upper limit of the output voltage range Vs, the duty ratio signal D is stopped and the operation of the DC-DC converter 11 is stopped. The control circuit 10 and the output voltage detector 1
4, output voltage range determination means 15, output voltage range setting unit 1
6. For the control unit A (see FIG. 5) including the reference voltage setting circuit 17, the control power supply Vcc (see FIG. 5) is switched from the control power supply Vcc (see FIG. 5) to the control unit A before the DC-DC converter 11 is powered on. Power is supplied. By thus supplying power to the control unit A in advance, it becomes possible to control the DC-DC conversion unit 11 after the operation of the control unit A becomes stable. It becomes possible to carry out stably. Here, in order to supply power to the control power supply Vcc before turning on the power to the DC-DC conversion unit 11, the control unit A is always connected to the control power supply Vcc, or the DC-DC conversion unit 11 and A timer circuit is used that generates the control power supply Vcc from the common DC power supply E and delays the power supply to the DC-DC converter 11 to the power supply to the controller A.

The above operation is summarized as shown in FIG. That is, when the DC power supply E is connected to the DC-DC conversion unit 11 and the power is turned on (S1), the output voltage Vo of the DC-DC conversion unit 11 detected by the output voltage detection unit 14 is output to the output voltage range setting unit 16. When the output voltage Vo exceeds the upper limit of the output voltage range Vs compared with the output voltage range Vs set in (S2), the operation of the DC-DC converter 11 is stopped (S3). On the other hand, when the output voltage Vo is equal to or lower than the upper limit value of the output voltage range Vs but equal to or higher than the lower limit value (S4), it is determined that the output voltage of the DC-DC converter 11 is in the normal range, and the DC-DC The operation of the conversion unit 11 is continued as it is. Further, when the output voltage Vo is smaller than the lower limit value of the output voltage range Vs (S4), the control voltage Vd is applied to the reference voltage setting circuit 17 to control the variable reference voltage Vref2 (S5), and the output voltage detection unit 14 is operated. The duty ratio signal D is corrected in such a direction as to increase the output voltage Vo of the DC-DC converter 11 as the difference between the output voltage Vo detected in 1 and the lower limit value of the output voltage range Vs increases.

The DC-DC converter 11 can be represented by an equivalent circuit in which an internal resistance is connected in series to a DC voltage source. In a general constant voltage power supply circuit that performs feedback control to keep the output voltage constant,
It can be said that the internal resistance in the equivalent circuit is relatively small because the output voltage is controlled to be constant even if the load 2 changes and the output current Io changes. On the other hand, in the power supply device 1 of the present embodiment, since the feedback control for keeping the output voltage Vo of the DC-DC converter 11 constant is not performed, the output voltage Vo varies with the variation of the load 2. Therefore, it can be said that the internal resistance of the equivalent circuit is relatively large. In other words, the change width of the voltage with respect to the change of the output current becomes large, so that the output current I as shown in FIG.
The slope of the straight line representing the relationship between o and the output voltage Vo becomes relatively large. Since there is a voltage drop due to the internal resistance as described above, it can be said that the fluctuation of the output current Io relative to the fluctuation of the output voltage Vo is relatively small. In other words, the output voltage Vo is maintained while the range in which the output current Io changes is kept relatively small.
Can be adjusted over a wide range.

However, when the load 2 is constant and the output voltage Vo is equal to or higher than the lower limit value of the output voltage range Vs, the control voltage Vd is not output, so the reference voltage Vref.
No change occurs, and the output voltage Vo is kept almost constant. Here, the reference voltage Vref is obtained by adding the variable reference voltage Vref2 to the fixed reference voltage Vref1, and when the output voltage Vo reaches the lower limit value of the output voltage range Vs, the variable reference voltage Vref2 becomes 0V (zero voltage). However, since the fixed reference voltage Vref1 is input to the control circuit 10, if the fixed reference voltage Vref1 is set appropriately, the output voltage Vo can be maintained at a voltage value slightly higher than the lower limit value of the output voltage range Vs. Is possible. in this way,
By maintaining the output voltage Vo at a voltage value higher than the lower limit value of the output voltage range Vs, a margin for voltage fluctuations due to fluctuations in the load 2 or the like can be obtained. That is,
The output voltage Vo is maintained in the output voltage range Vs even if the load 2 slightly changes.

On the other hand, the load 2 has a large capacity and the output current is I
When o increases and the output voltage Vo falls below the lower limit value of the output voltage range Vs, the output voltage Vo becomes equal to the output voltage range Vs.
The reference voltage Vref rises and DC
An attempt is made to increase the output voltage Vo of the −DC converter 11. At this time, the output voltage Vo returns to the output voltage range Vs again if the capacity of the load 2 is within a range that can be handled by the change in the reference voltage Vref. However, the reference voltage Vre
Since f has a maximum value, when the load 2 has a large capacity, the output of the DC-DC converter 11 is limited by the duty ratio signal D when the reference voltage Vref becomes maximum. That is, the output voltage Vo becomes a substantially constant voltage lower than the lower limit value of the output voltage range Vs.

As described above, in this embodiment, when the output voltage Vo exceeds the upper limit value of the output voltage range Vs, the operation of the DC-DC converter 11 is stopped. This is when the load 2 is very small,
This is because a surplus occurs in the output of the DC-DC conversion unit 11 and the output voltage Vo of the DC-DC conversion unit 11 may rise abnormally. By setting the upper limit of the output voltage Vo, DC- It is possible to prevent an increase in voltage stress on the components of the DC converter 11 and to prevent an abnormally high voltage from being applied to the load 2.

By the way, when the power is supplied from the single power feeding device 1 to the load 2, when the power consumption of the load 2 (capacity of the load 2) is large, the DC-D
The output voltage Vo of the C converter 11 may fall below the lower limit value of the output voltage range Vs. Therefore, when the output current Io of the power feeding device 1 is insufficient, parallel power feeding is performed by connecting a plurality of (three in the figure) power feeding devices 1 in parallel to the load line Ls as shown in FIG. That is, the load line L
A plurality of power supply devices 1 are commonly connected to s, and power is supplied from the plurality of power supply devices 1 to the load 2.
If the power is supplied to the load 2 in such a manner, the power that can be supplied is increased as compared with the case where only one power feeding device 1 supplies the power to the power receiving device 2.

In the illustrated example, electric power is supplied to the power supply devices 1a to 1c from the DC power supplies Ea to Ec, respectively, and the voltage is controlled by the DC-DC converter 11 provided in each of the power supply devices 1a to 1c. Here, each of the power feeding devices 1a to 1c has the same configuration as the power feeding device 1 shown in FIG. Switches SWa to SWc are inserted between the power supply devices 1a to 1c and the DC power supplies Ea to Ec, respectively.
The power supply from the DC power supplies Ea to Ec to the 1c can be turned on and off separately.

Here, it is assumed that the current capacities of the output currents Ioa to Ioc of the power supply devices 1a to 1c are set to the extent that the current consumption of the load 2 can be satisfied by three units. Now, as shown in FIGS. 6A to 6C, if the switches SWa to SWc are sequentially turned on to sequentially start the supply of the DC power supplies Ea to Ec to the power supply devices 1a to 1c, The reference voltages Vrefa and Vrefb generated in the power feeding devices 1a and 1b are the switches SWa and SWb.
6 starts to rise from the time of charging and reaches the maximum values Ma and Mb as shown in FIGS. That is, in the illustrated example, the two power supply devices 1a and 1b cannot supply a sufficient current to the load 2, and therefore the reference voltages Vrefa and Vref.
Even if b reaches the maximum values Ma and Mb, respectively, as shown in FIG. 6G, the output voltage Vo of the DC-DC converter 11 does not reach the output voltage range Vs, and the line voltage of the load line Ls becomes The voltage becomes lower than the lower limit value of the output voltage range Vs. here,
When the switch SWc is turned on as shown in FIG. 6C, the reference voltage Vrefc rises as shown in FIG. 6F. Here, even if the reference voltage Vrefc does not reach the maximum value Mc, the power supply to the load 2 is satisfied, so that the reference voltage Vref
refc does not reach the maximum value Mc, and DC-DC
The converter 11 will be controlled. In this state,
As shown in (g), the line voltage of the load line Ls is the output voltage range V
s is reached, and the power supply to the load 2 is stably performed.

As is apparent from the above operation, if the power supply device 1 is added in accordance with the power consumption of the load 2, the load line L
It is possible to secure the required output current Io while keeping the line voltage of s within the output voltage range Vs. Moreover, when the power consumption in the load 2 becomes smaller than the power supplied from the power supply device 1, the operation of the DC-DC converter 11 in the unnecessary power supply device 1 is stopped, and the useless operation of the power supply device 1 is prevented. It

The power supply device 1 in this embodiment is
As is clear from the above operation, since the feedback control for keeping the output voltage constant is not performed, the line voltage of the load line Ls varies. Therefore, load 2
If a constant voltage is required in, the load 2 must be provided with a constant voltage power supply.

(Second Embodiment) This embodiment is shown in FIG.
As shown in FIG. 1, an output current detector 18 for detecting the output current Io of the DC-DC converter 11 is provided in the configuration of the first embodiment shown in FIG. 1, and the output voltage Vo is the same as that of the first embodiment. The control is performed in the same manner as in the form, and the output current Io is controlled so as to maintain the limit value. That is, DC-
The limit value Is for the output current Io of the DC conversion unit 11 is set by the constant current value setting unit 19, and the output current Io and the limit value Is are compared by the output current determination means 20. Here, the output current from the output current detector 18 is DC
The current (or voltage) is proportional to the output current Io of the -DC converter 11, and can be treated as equivalent to the output current Io of the DC-DC converter 11. Therefore, in the following, both currents will be used without distinction unless otherwise necessary.

In the present embodiment, in order to limit the output current Io, the difference between the output current Io and the limit value Is is obtained by the output current determination means 20, and the current control signal Id corresponding to this difference is output. When the output current Io reaches the limit value Is, as shown in FIG. 8, the DC-DC converter 11 is controlled through the control circuit 10 so that the output current Io detected by the output current detector 18 maintains the limit value Is. Control. That is, the maximum value of the output current Io of the power feeding device 1 is limited to the limit value Is, and the output voltage Vo is controlled in the range in which the output current Io becomes the limit value Is or less.

Therefore, as described with reference to FIG. 5 in the first embodiment, a plurality of power supply devices 1a to 1c.
Is connected to the load line Ls to supply power to the load 2 in parallel, the operation is performed as shown in FIG. Here, it is assumed that the power consumption of the load 2 is covered by the three power supply devices 1a to 1c.

9A to 9C in the connection state of FIG.
As shown in (c), if the switches SWa to SWc are sequentially turned on and the DC power supplies Ea to Ec are connected to the power supply devices 1a to 1c, respectively, the single power supply device 1a alone supplies a sufficient current to the load 2. 9 (g), the output current Ioa of the power feeding device 1a reaches the limit value Is as soon as the switch SWa is turned on, and the output voltage Vo is increased as shown in FIG. 9 (d). ), The reference voltage Vrefa becomes the maximum value Ma. At this stage, the line voltage of the load line Ls is the output voltage range Vs as shown in FIG.
Does not reach. Here, the output current Io of the power supply device 1a
The constant current operation is performed from the time a reaches the limit value Is until the reference voltage Vrefa reaches the maximum value Ma.

Since a sufficient current is not supplied to the load 2 even when the DC power source Eb is connected to the power feeding device 1b, FIG.
As shown in (h), the output current Iob of the power supply device 1b reaches the limit value Is, and the reference voltage Vrefb becomes the maximum value Mb as shown in FIG. 9 (e). After that, the DC power source E is supplied to the power feeding device 1c.
When c is connected, the amount of current supplied to the load 2 is satisfied, so that the output current I as shown in FIG.
oc is maintained at a substantially constant value without reaching the limit value Is. At this time, as shown in FIG. 9F, the output voltage also has a substantially constant value, so the reference voltage Vrefc also has the maximum value Mc.
And the line voltage of the load line Ls does not reach the output voltage range Vs.
Will fit in. Here, in FIG. 9 (j), when the switch SWb is turned on, the output voltage Vo exceeds the lower limit value of the output voltage range Vs before the switch SWc is turned on, but as described in the first embodiment as well. , Output voltage V
o is designed so as to reach a voltage value slightly higher than the lower limit value, thereby ensuring a margin for fluctuations in the load 2. Other configurations are similar to those of the first embodiment.

(Third Embodiment) This embodiment is shown in FIG.
0, a feedback gain setting circuit 21 is provided in place of the reference voltage setting circuit 17 in the configuration of the first embodiment, and the feedback gain setting circuit 21 is detected by the output voltage detection unit 14. A reference voltage Vr to the control circuit 10 based on the output voltage Vo of the DC-DC converter 11, the control voltage Vd output from the output voltage range determination means 15, and the feedback reference voltage Vref0.
ef is generated. That is, in the range in which the output voltage Vo of the DC-DC converter 11 is lower than the lower limit value of the operating range voltage Vs, the output voltage range determination means 15 outputs the output voltage Vo and the lower limit value as shown in FIG. The control voltage Vd that increases as the difference increases is output, and the feedback gain setting circuit 21 sets the feedback gain G that increases in proportion to the control voltage Vd as shown in FIG. 11B. Therefore, in a range where the output voltage Vo is lower than the lower limit value of the output voltage range Vs, the feedback gain G increases as the difference between the output voltage Vo and the lower limit value increases. However, the maximum value is set for the feedback gain. Further, the feedback gain G becomes 0 when the output voltage Vo is higher than the lower limit value of the output voltage range Vs, and when the output voltage Vo exceeds the upper limit value of the output voltage range Vs, the operation of the DC-DC converter 11 is performed. Stop.

By the way, the feedback gain setting circuit 2
The reference numeral 1 error-amplifies the error voltage between the output voltage Vo of the DC-DC converter 11 and the feedback reference voltage Vref0 by the feedback gain G set based on the control voltage Vd as described above, and the result of the error amplification is obtained. Reference voltage Vre
It is given to the control circuit 10 as f. Therefore,
The control circuit 10 outputs the output voltage Vo of the DC-DC converter 11.
Is lower than the lower limit value of the output voltage range Vs, the output voltage Vo is controlled to approach the feedback reference voltage Vref0. In addition, the feedback gain G is set to the maximum value as described above, the feedback gain G is set by the control voltage Vd generated based on the output voltage Vo, and the feedback gain setting circuit 21 has a fixed feedback reference value. Voltage Vref
0 is the error voltage between the output voltage Vo and the feedback gain G
Since the error is amplified by, the reference voltage Vref output from the feedback gain setting circuit 21 eventually has a constant maximum value. The reference voltage Vref output from the feedback gain setting circuit 21 is the control circuit 10
Is input to the reference voltage Vref as shown in FIG.
The higher the ratio, the larger the duty ratio is
Is output from. The duty ratio defines the minimum value when the reference voltage Vref is 0 V, and the reference voltage Vref is 0.
Even with V, the duty ratio signal D having a predetermined duty ratio is output.

The above operation is summarized as shown in FIG. That is, when the DC power supply E is connected to the DC-DC converter 11 and the power is turned on (S1), the output voltage detector 14
The output voltage Vo of the DC-DC conversion unit 11 detected in step S1 is compared with the output voltage range Vs set by the output voltage range setting unit 16, and when the output voltage Vo exceeds the upper limit value of the output voltage range Vs (S2 ), The operation of the DC-DC converter 11 is stopped (S3). On the other hand, when the output voltage Vo is equal to or lower than the upper limit value of the output voltage range Vs but equal to or higher than the lower limit value (S4), it is determined that the output voltage of the DC-DC converter 11 is in the normal range, and the DC-DC The operation of the conversion unit 11 is continued as it is. Further, when the output voltage Vo is smaller than the lower limit value of the output voltage range Vs (S4), the feedback gain is determined by applying the control voltage Vd to the feedback gain setting circuit 21, and the output voltage Vo becomes the feedback reference voltage Vref0. Feedback control is performed so as to approach (S5). However, since the feedback gain G has the maximum value, the feedback gain G becomes maximum when the capacity of the load 2 is large,
The output voltage Vo becomes a voltage according to the capacity of the load 2.

By the operation as described above, as shown in FIG. 13, it becomes possible to change the relationship between the output voltage Vo and the output current Io of the DC-DC converter 11 according to the size of the load 2. . That is, the slope of the straight line shown in FIG. 13 changes according to the feedback gain G.

However, when the power consumption of the load 2 is relatively large with respect to the output of the power supply device 1, the output voltage Vo decreases as the output current Io increases, but the output voltage Vo increases.
Is larger than the lower limit value of the output voltage range Vs, feedback control is not performed, so that the duty ratio signal D output from the control circuit 10 is maintained at the initial value. On the other hand, when the output voltage Vo falls below the lower limit value of the output voltage range Vs,
A control voltage Vd is generated, feedback control is performed, and D
An attempt is made to increase the output voltage Vo of the C-DC converter 11. Here, if the output voltage Vo is again within the range of the output voltage range Vs, the feedback control is not performed and the output voltage Vo is maintained at the voltage value of the output voltage range Vs. On the other hand, when the capacity of the load 2 is large and the feedback gain G reaches the maximum value, the output voltage Vo becomes the output voltage range Vs.
The predetermined voltage is reached without reaching the lower limit value of.

Therefore, similar to the first embodiment, three power supply devices 1 of the present embodiment are connected to the load line Ls in the form shown in FIG. 5, and parallel power supply to the load 2 is performed. For example, the power supply device 1 of the present embodiment operates as shown in FIG. Now, the output current Io of each of the power supply devices 1a to 1c
It is assumed that the current capacity of 3 is set to the extent that the current consumption of the load 2 can be satisfied by 3 units. 14
As shown in (a) to (c), each switch SWa to SW
By sequentially turning on c, the respective power supply devices 1a to 1c
When the supply of the DC power supplies Ea to Ec is sequentially started, the feedback gain in the power feeding devices 1a and 1b is large immediately after the switches SWa and SWb are turned on, and thereafter,
The output voltage Vo of each power supply device 1a, 1b is the output voltage range V
The feedback gain G becomes smaller as it approaches s. That is, the reference voltages Vrefa and Vrefb output from the feedback gain setting circuit 21 of each power feeding device 1a and 1b.
Increases as shown in FIGS. 14D and 14E, and increases the line voltage of the load line Ls as shown in FIG. However, 2
If the power supply devices 1a and 1b are connected together, the load line Ls
Line voltage does not reach the output voltage range Vs.
When the switch SWc is turned on as shown in FIG. 14C so as to connect the DC power source Ec to c, the reference voltage Vrefc output from the feedback gain setting circuit 21 rises as shown in FIG. Load line L as shown in (g)
The line voltage of s reaches the output voltage range Vs. That is, the line voltage of the load line Ls reaches the output voltage range Vs, and the power supply to the load 2 is stably performed. The reference voltage Vref input to the control circuit 10
a, Vrefb, Vrefc are feedback gains G
The maximum values La, Lb, and Lc are defined according to the maximum value set for the above and the capacity of the load 2. Other configurations and operations are similar to those of the first embodiment.

(Fourth Embodiment) This embodiment is shown in FIG.
As shown in FIG. 5, a configuration in which an output current detection unit 18, a constant current value setting unit 19, and an output current determination unit 20 having the same functions as those of the second embodiment is added to the third embodiment. Have. Therefore, the relationship between the output current Io and the output voltage Vo of the power supply device 1 of the present embodiment changes as shown in FIG. 16 according to the feedback gain. in short,
In addition to the operation of the third embodiment, the maximum value of the output current Io is set as the limit value Is.

Therefore, when the three power feeding devices 1a to 1c are connected to the load line Ls and the switches SWa to SWc are sequentially turned on as shown in FIG. 5, the operation is as shown in FIG. Become. That is, FIG.
As shown in (c), when the DC power supplies Ea to Ec are sequentially supplied to the power feeding devices 1a to 1c by sequentially turning on the switches SWa to SWc, the power feeding device 1
The feedback gain in a and 1b is the switch SW.
It is large immediately after a and SWb are turned on, and then the feedback gain G becomes small when the output voltage Vo of each of the power feeding devices 1a and 1b approaches the output voltage range Vs. That is,
As shown in FIG. 17 (g), as soon as the switch SWa is turned on, the output current Ioa of the power feeding device 1a reaches the limit value Is, and the output voltage Vo is tried to be raised.
The reference voltage Vrefa rises as shown in (d). At this stage, the line voltage of the load line Ls does not reach the output voltage range Vs as shown in FIG. 17 (j). Power supply device 1a
Of the reference voltage V after the output current Ioa reaches the limit value Is.
The constant current operation is performed while refa rises.

Even when the DC power source Eb is connected to the power feeding device 1b, a sufficient current is not supplied to the load 2.
The output current Iob of the power supply device 1b reaches the limit value Is as shown in 7 (h), and the reference voltage Vref as shown in FIG. 17 (e).
b rises. After that, when the DC power source Ec is connected to the power feeding device 1c, the amount of current supplied to the load 2 is satisfied, so that the output current Io is increased as shown in FIG.
c is maintained at a substantially constant value without reaching the limit value Is. At this time, since the output voltage also becomes a substantially constant value, the line voltage of the load line Ls becomes the output voltage range V before the reference voltage Vrefc rises to the maximum as shown in FIG.
It will fit in s. In the present embodiment as well, the output voltage Vo of the DC-DC conversion unit 11 cannot be increased even if the reference voltages Vrefa to Vrefc are increased without limit. Therefore, an upper limit value is set for the reference voltages Vrefa to Vrefc. There is. Other configurations are similar to those of the first embodiment.

(Fifth Embodiment) As shown in FIG. 18, the power feeding device 1 according to the fifth embodiment is basically the same as the power feeding device 1 according to the first embodiment shown in FIG. is there. However, the power feeding device 1 of the present embodiment has a function of transmitting and receiving data between the power feeding devices 1 when a plurality of power feeding devices 1 are connected to the load line Ls and parallel power feeding is performed.

That is, the structure for transmitting data is provided in the control circuit 10, and the control circuit 10 changes the line voltage of the load line Ls by modulating the duty signal D according to the data to be transmitted. , The content of the data is transmitted as a change in the line voltage of the load line L.
It is possible to adopt various types of modulation methods,
In the present embodiment, a pulse width modulation method is adopted in which the width of the period when the line voltage is high is changed according to the binary data value. That is, the transmission signal is sent in a form in which the data is superimposed on the DC voltage output from the power feeding device 1. Further, an address is used to identify the source and destination of the data, and the address of each power supply device 1 is held in the address setting means 22 connected to the control circuit 10. The address setting means 22 is a mechanical digital switch (for example, DI
P switch) or memory switch (EEPROM)
To use.

On the other hand, as a structure for receiving data, a signal detecting section 23 for detecting the line voltage of the load line Ls is provided. The reception signal Vrx extracted by the signal detection unit 23 by detecting the change in the line voltage of the load line Ls is input to the control circuit 10. That is, when the transmission signal superimposed on the line voltage of the load line Ls is detected as the reception signal Vrx by the signal detection unit 23, the control circuit 10 receives the reception signal Vref.
The address included in is compared with the address set in the address setting means 22, and if they match, the control circuit 1
At 0, a command is extracted from the received signal Vrx, and control according to the command is performed. In this way, the control circuit 1
0 functions as a transmission means for transmitting information between the power feeding devices through the load line Ls. Here, this embodiment is DC-DC.
An output current detection unit (current detection means) 24 that detects the output current from the conversion unit 11 is also provided.

An example of the operation of this embodiment will be described. Here, similarly to the configuration shown in FIG. 5, three power feeding devices 1a to
A case where 1c is connected to the load line Ls will be described. However, the power feeding devices 1a to 1c are not in an equal relationship, and the power feeding device 1a operates as a master and the other power feeding devices 1b and 1c operate as slaves for data transmission. That is, the power feeding device 1a having an address of 0 is a master, and the power feeding devices 1b and 1c having other addresses set therein (specifically, the address of the power feeding device 1b is 1 and the address of the power feeding device 1c is 2) are slaves. And

Now, as shown in FIG. 19, the switch SW
It is assumed that a to SWc are turned on and the line voltage of the load line Ls is in the output voltage range Vs. When this condition is not satisfied, it is determined that the output currents of the power supply devices 1a to 1c are insufficient or it is a period during which the output voltage is controlled,
Only when the above conditions are satisfied, the load balancing operation described below is performed.

In the load distribution operation, the power supply device 1 is a master in which the line voltage of the load line Ls is in the output voltage range Vs.
It starts when it is confirmed in a. That is, at this time point, the master power supply apparatus 1a transmits the output current value confirmation command to the two slave power supply apparatuses 1b and 1c, respectively. Each power supply device 1 that becomes a slave
When the output current value confirmation command is received at b and 1c, the current value detected by the output current detection unit 24 is transmitted together with the output current value notification command to the master power supply device 1a. In this way, the master power supply apparatus 1a knows the output currents of all the power supply apparatuses 1a to 1c. Therefore, the current values notified from the slave power supply apparatuses 1b and 1c and the output current of the master power supply apparatus 1a. The current value required for the load 2 can be known by obtaining the sum of and. If the specifications of the power supply devices 1a to 1c are the same except for the address, the power supply devices 1a to 1c are specified.
In order to distribute the output currents of 1 with good balance, the average value of the sum total of the output currents obtained as described above may be obtained.
Therefore, in the present embodiment, the average current value is calculated in the master power supply device 1a. However, each power supply device 1a-
If the specifications of 1c are different, the currents to be allocated to the power supply devices 1a to 1c are obtained according to the ratio of the current capacities so that the currents are distributed according to the current capacities of the power supply devices 1a to 1c. In this case, the power supply devices 1b and 1c that are slaves
It is desirable that the current capacity of 1 is transmitted to the power supply device 1a as the master through the load line Ls. Since these calculations are performed in the control circuit 10, the control circuit 10 of the power feeding device 1a obtains the sum total of the current values of the output currents transmitted from the other power feeding devices 1b and 1c, and each power feeding device 1a.
It also has a function as a current distribution means for distributing and allocating current values according to the current capacity of 1c.

When the current value of the output current to be distributed to each of the power feeding devices 1a to 1c is obtained as described above, the power feeding device 1a that is the master is the power feeding devices 1b and 1c that are the slaves.
The current value obtained by the output current value setting command is transmitted to each. Further, an output current value control start command is transmitted to the power feeding devices 1b and 1c, and the power feeding device 1b
The output currents of b and 1c are controlled so as to have the current value set by the output current value setting command. That is, the control circuit 10 of each of the power supply devices 1a to 1c also functions as a control unit that controls the output current detected by the current detection unit 24 so as to have the current value assigned by the power supply device 1a. By such control, each of the power supply devices 1a to 1c can supply the current required for the load 2 to the load line Ls while supplying the current in a well-balanced manner according to the current capacity of each of the power supply devices 1a to 1c. It will be possible. After that, each power supply device 1
In a to 1c, the line voltage of the load line Ls is the output voltage range Vs.
Take control so that it does not come off. That is, each power supply device 1
The reference voltage Vref is controlled so that the output voltages Vo of a to 1c fall within the output voltage range Vs.

In the master power supply device 1a, after the output current value control start command is transmitted to adjust the current value of the output current Io, the output current Io detected by the output current detector 24 is detected.
If the output voltage Vo detected by the output voltage detection unit 14 is confirmed and the output current Io is a distributed current value and the output voltage Vo is the output voltage range Vs, the output of all the power supply devices 1a to 1c. It is determined that the current has reached the set value, and the output current control stop command is transmitted to each of the slave power supply devices 1b and 1c. In this way, in each of the power supply devices 1a to 1c, the control of the output current is stopped, and thereafter, the operation is performed in the same state.

By the above-described operation, each power feeding device 1
The output currents a to 1c are distributed in good balance according to the current capacity. As described above, the operation of distributing the load current is called a load distributing operation in this embodiment. In addition, in the operation example of FIG. 19, the case where the number of the power supply devices 1 is three is illustrated, but the same operation is performed when a larger number of power supply devices 1 are provided. In addition, the configuration of the power feeding device 1 is the first
The present invention is not limited to the configuration of the embodiment, and the technical idea of the present embodiment can be applied to the configurations described in other embodiments. Further, in the above example, the power supply devices 1a to 1c are operated in the master-slave relationship, but it is also possible to perform data transmission with the power supply devices 1a to 1c having an equal relationship.

[0057]

According to the first aspect of the present invention, a DC power supply unit for changing the output voltage according to a separately input control signal, an output voltage detection unit for detecting the output voltage of the DC power supply unit, and the output voltage And an output voltage range setting unit that sets the voltage range of the output voltage range as an output voltage range, and the output voltage increases as the difference between the output voltage and the lower limit value increases in a range in which the output voltage is less than the lower limit value of the output voltage range. And a voltage control section for giving a control signal to the DC power supply section, the control signal being generated so as to have a maximum value regulated, and the output voltage and the lower limit only when the output voltage is lower than the lower limit value of the output voltage range. The control signal is generated so as to increase the output voltage as the difference from the value is larger.However, since the maximum value of the control signal is regulated, when the current capacity for the load is insufficient, the control signal becomes the maximum. Output voltage reaches the predetermined voltage in a state that reaches a value. That is, when the current capacity for the load is satisfied by connecting multiple units to the load line, the output voltage of all the power supply devices can reach the output voltage range, and as a result, the output voltage is automatically adjusted. Will be done. As a result, it is not necessary to perform control to control the power supply devices only by connecting the power supply devices for the number of devices that can satisfy the current capacity for the load, and power can be supplied with reduced wiring even when using a plurality of power supply devices. It will be possible. Moreover, since each power supply device can be independently connected to the load line, there is no need to install each power supply device in one place, and there is an advantage that the installation place is highly flexible. As a result, when multiple power supply devices are connected as a standby power supply, each power supply device is installed in a remote place, and the input power system of each power supply device is a separate system.
Even when a failure occurs in one of the input power supply systems, the other power supply device is operated to avoid an accident in which the entire system stops. In addition, since each power supply device automatically adjusts the output voltage, it is possible to add or remove power supply devices without making any special settings even when the system is live, which enhances system expandability, workability, and maintainability. Has the advantage. Furthermore, since the output voltage of each power supply device is only monitored and the output voltage is adjusted, the system does not become unstable.

According to a second aspect of the present invention, a DC power supply unit that changes the output voltage according to a separately input control signal, an output voltage detection unit that detects the output voltage of the DC power supply unit, and a voltage of the output voltage. An output voltage range setting unit that sets a range as an output voltage range, and outputs a control voltage that increases as the difference between the output voltage and the lower limit value increases in a range in which the output voltage is less than the lower limit value of the output voltage range. Output voltage range determination means for setting the control voltage to a zero voltage in a range equal to or higher than the lower limit value of the output voltage range, and a reference voltage for generating a reference voltage having a higher maximum and a restricted maximum value A setting circuit, and a control circuit for giving a control signal generated to increase the output voltage of the DC power supply unit to a higher reference voltage to the DC power supply unit,
Only when the output voltage is lower than the lower limit of the output voltage range, a control voltage that increases as the difference between the output voltage and the lower limit increases is generated, and the maximum value of the reference voltage generated based on this control voltage is regulated. Since the maximum value of the control signal generated from the reference voltage is regulated by doing so, when the current capacity for the load is insufficient, the output voltage becomes the predetermined voltage with the control signal reaching the maximum value. That is, when the current capacity for the load is satisfied by connecting multiple units to the load line, the output voltage of all the power supply devices can reach the output voltage range, and as a result, the output voltage is automatically adjusted. Will be done. As a result, it is not necessary to perform control to control the power supply devices only by connecting the power supply devices for the number of devices that can satisfy the current capacity for the load, and power can be supplied with reduced wiring even when using a plurality of power supply devices. It will be possible. Moreover, since each power supply device can be independently connected to the load line, there is no need to install each power supply device in one place, and there is an advantage that the installation place is highly flexible. As a result, when multiple power supply devices are connected as a standby power supply, each power supply device is installed in a remote place, and the input power system of each power supply device is a separate system. Even when a failure occurs in one of the input power supply systems, the other power supply device is operated to avoid an accident in which the entire system stops. In addition, since each power supply device automatically adjusts the output voltage, it is possible to add or remove power supply devices without making any special settings even when the system is live, which enhances system expandability, workability, and maintainability. Has the advantage. Furthermore, since the output voltage of each power supply device is only monitored and the output voltage is adjusted, the system does not become unstable.

According to a third aspect of the invention, in the second aspect of the invention, the reference voltage is generated by adding a variable reference voltage that changes according to the control voltage to a preset fixed reference voltage. The final output voltage can be adjusted by appropriately setting the fixed reference voltage.

According to a fourth aspect of the present invention, a DC power supply unit that changes the output voltage according to a separately input control signal, an output voltage detection unit that detects the output voltage of the DC power supply unit, and a voltage of the output voltage. An output voltage range setting unit that sets a range as an output voltage range, and outputs a control voltage that increases as the difference between the output voltage and the lower limit value increases in a range in which the output voltage is less than the lower limit value of the output voltage range. Output voltage range determination means for setting the control voltage to zero in a range that is equal to or higher than the lower limit value of the output voltage range, and a feedback gain that increases as the control voltage increases and whose maximum value is regulated A feedback gain setting circuit that error-amplifies an error voltage between a voltage and a specified feedback reference voltage to generate a reference voltage; A control circuit that gives a control signal generated to increase the pressure to the DC power supply unit, and the difference between the output voltage and the lower limit value is only when the output voltage is lower than the lower limit value of the output voltage range. The higher the control voltage, the higher the control voltage generated, and the maximum value of the feedback gain generated based on this control voltage that limits the maximum value of the control signal generated from the reference voltage. When the capacity is insufficient, the output voltage becomes the predetermined voltage with the control signal reaching the maximum value. That is, when the current capacity for the load is satisfied by connecting multiple units to the load line, the output voltage of all the power supply devices can reach the output voltage range, and as a result, the output voltage is automatically adjusted. Will be done. As a result, it is not necessary to perform control to control the power supply devices only by connecting the power supply devices for the number of devices that can satisfy the current capacity for the load, and power can be supplied with reduced wiring even when using a plurality of power supply devices. It will be possible. Moreover,
Since each power supply device can be independently connected to the load line, there is no need to install each power supply device in one place, and there is an advantage that the installation place is highly flexible. As a result, when connecting multiple power supply devices as a standby power source,
By installing each power supply device in a remote place and using a separate input power supply system for each power supply device, other power supply devices can operate even if a failure occurs in one of the input power supply systems By doing so, it is possible to avoid an accident in which the entire system stops. In addition, since each power supply device automatically adjusts the output voltage, it is possible to add or remove power supply devices without making any special settings even when the system is live, which enhances system expandability, workability, and maintainability. Has the advantage. Furthermore, since the output voltage of each power supply device is only monitored and the output voltage is adjusted, the system does not become unstable. In addition, by performing the feedback control, there is an advantage that the fluctuation of the output voltage can be suppressed even when a sudden load fluctuation occurs.

According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, the DC power supply unit is a switching power supply circuit, and the ON / OFF ratio of a switching element forming the DC power supply unit is controlled as the control signal. Since the duty ratio signal is used, efficient power conversion is possible by using the switching power supply circuit, and furthermore, the well-known integrated circuit for the PWM circuit can be used as the control circuit. Since no special circuit configuration is required, an increase in cost can be suppressed.

According to a sixth aspect of the present invention, in the first to fifth aspects of the present invention, an output current detecting section for detecting the output current of the DC power source section and a constant current for setting a limit value of the output current that can be supplied. A value setting unit and an output current determining unit that limits a control signal output from the control circuit so that the output current does not exceed the limit value.The output current is limited when the output current increases. As a result, constant current operation is performed, and the power supply device can be protected from an accident such as a load short circuit.

According to a seventh aspect of the present invention, in a power feeding system including a plurality of power feeding devices connected in parallel to a set of load lines to which a load serving as a load is connected, each power feeding device is the first power feeding system.
7. A power supply device according to claim 6, further comprising: current detection means for detecting an output current when the line voltage of the load line reaches an output voltage range which is a voltage range required to operate the load; A power supply device, which further includes a transmission unit that transmits information between the devices via the load line, and a control unit that controls the output current detected by the current detection unit to have a current value assigned thereto. Any one of the power supply devices includes a current distribution unit that calculates a sum of current values of output currents transmitted from the power supply devices through the transmission unit and distributes and allocates the current value according to the current capacity of each power supply unit. The current value assigned to the other power supply device is notified to the other power supply terminal by the transmission means. With this configuration, while the current necessary for the load is ensured, the power supply according to the capability of each power supply device is obtained. Allocation enabling the current stress in the power supply device can be well-balanced distribution. In other words, it is possible to prevent the output bias such that only one of the power supply devices operates at the maximum capacity, and distribute the output current according to the current capacity of each power supply device, which leads to a longer life. .

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of the above.

FIG. 3 is an operation explanatory diagram of the above.

FIG. 4 is an operation explanatory diagram of the above.

FIG. 5 is a block diagram showing a usage example of the above.

6 is an operation explanatory view when the same is used in the form shown in FIG. 5. FIG.

FIG. 7 is a block diagram showing a second embodiment of the present invention.

FIG. 8 is an operation explanatory diagram of the above.

9 is an operation explanatory diagram when the same is used in the form shown in FIG. 5. FIG.

FIG. 10 is a block diagram showing a third embodiment of the present invention.

FIG. 11 is an operation explanatory diagram of the above.

FIG. 12 is an explanatory diagram of an operation of the above.

FIG. 13 is an operation explanatory diagram of the above.

FIG. 14 is an operation explanatory diagram when the same is used in the form shown in FIG. 5;

FIG. 15 is a block diagram showing a fourth embodiment of the present invention.

FIG. 16 is an explanatory diagram of an operation of the above.

17 is an operation explanatory diagram when the same is used in the form shown in FIG. 5. FIG.

FIG. 18 is a block diagram showing a fifth embodiment of the present invention.

FIG. 19 is an operation explanatory diagram when the same is used in the form shown in FIG. 5;

FIG. 20 is a block diagram showing a conventional example.

[Explanation of symbols]

1 power supply device 2 load 10 Control circuit 11 DC-DC converter 11a-11c DC-DC converter 14 Output voltage detector 15 Output voltage range determination means 16 Output voltage range setting section 17 Reference voltage setting circuit 18 Output current detector 19 Constant current value setting section 20 Output current judging means 21 Feedback gain setting circuit 22 Address setting means 23 Signal detector 24 Output current detector D time ratio signal E DC power supply Ea-Ec DC power supply Io output current L load Ls load line Vd control voltage Vo output voltage Vref reference voltage Vref1 fixed reference voltage Vref2 movable reference voltage Vrefa to Vrefc reference voltage Vs output voltage range

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-10-243639 (JP, A) JP-A-11-150875 (JP, A) JP-A-4-109874 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H02M 3/00 H02J 1/10 H04Q 9/00 H04M 19/08

Claims (7)

(57) [Claims] 1. A DC power supply unit that changes an output voltage according to a separately input control signal, an output voltage detection unit that detects an output voltage of the DC power supply unit, and a voltage range of the output voltage is an output voltage range. And an output voltage range setting unit that sets the output voltage as a maximum value in a range in which the output voltage is less than the lower limit value of the output voltage range. A power supply device, comprising: a voltage control unit that supplies a control signal whose value is regulated to the DC power supply unit. 2. A DC power supply unit that changes an output voltage according to a separately input control signal, an output voltage detection unit that detects an output voltage of the DC power supply unit, and a voltage range of the output voltage is an output voltage range. And an output voltage range setting unit that outputs a control voltage that increases as the difference between the output voltage and the lower limit value increases in a range in which the output voltage is less than the lower limit value of the output voltage range. An output voltage range determining means for setting the control voltage to a zero voltage in a range equal to or more than the lower limit value, a reference voltage setting circuit for generating a reference voltage whose control voltage becomes higher and the maximum value is regulated, A power supply device, comprising: a control circuit that gives a control signal to the DC power supply unit, the control signal being generated such that the higher the voltage, the higher the output voltage of the DC power supply unit. 3. The power supply device according to claim 2, wherein the reference voltage is generated by adding a variable reference voltage that changes according to the control voltage to a preset fixed reference voltage. 4. A DC power supply unit that changes an output voltage according to a separately input control signal, an output voltage detection unit that detects an output voltage of the DC power supply unit, and a voltage range of the output voltage is an output voltage range. And an output voltage range setting unit that outputs a control voltage that increases as the difference between the output voltage and the lower limit value increases in a range in which the output voltage is less than the lower limit value of the output voltage range. Output voltage range determining means for setting the control voltage to a zero voltage in a range that is equal to or more than the lower limit value, and a feedback gain that increases as the control voltage increases and the maximum value is regulated to set the output voltage and the specified feedback. A feedback gain setting circuit that error-amplifies an error voltage with respect to a reference voltage to generate a reference voltage, and increases the output voltage of the DC power supply unit as the reference voltage increases. And a control circuit that supplies the control signal generated in step 1 to the DC power supply unit. 5. The DC power supply unit is a switching power supply circuit, and a duty ratio signal for controlling an ON / OFF ratio of a switching element constituting the DC power supply unit is used as the control signal. 4. The power feeding device according to any one of 4. 6. An output current detection unit that detects an output current of the DC power supply unit, a constant current value setting unit that sets a limit value of an output current that can be supplied, and an output current that does not exceed the limit value. The power supply device according to claim 1, further comprising: an output current determination unit that limits a control signal output from the control circuit. 7. A power supply system comprising a plurality of power supply devices connected in parallel to a set of load lines to which a load serving as a load is connected, wherein each power supply device is a power supply device according to any one of claims 1 to 6. In the device, a current detection unit that detects an output current when the line voltage of the load line reaches an output voltage range that is a voltage range required to operate the load, and the load line between the power supply device and the power supply device. A power feeding device, further comprising: a transmitting means for transmitting information, and a control means for controlling the output current detected by the current detecting means so that the output current has an assigned current value. The total value of the output currents transmitted from the power supply device through the transmission means is calculated, and the current value is allocated according to the current capacity of each power supply device. A power supply system characterized in that the flow value is notified to another power supply terminal by a transmission means.