JP2018161014A - High-speed parallel unit control type dc power supply unit - Google Patents

Abstract

A parallel unit control type DC power supply device capable of high-speed operation by using a limit circuit is provided. In a DC power supply device of a parallel unit control system that controls a plurality of power supply units connected in parallel, a unit current average signal obtained by averaging current values output from each power supply unit is compared with a reference voltage to obtain a single unit One error amplifier that outputs a control signal, a connection part that branches the single control signal output from the error amplifier to each power supply unit, and a power supply unit that is provided with the branched control signal, A DC power supply device having a limit circuit that is limited by a limit signal in each power supply unit was used. [Selection] Figure 3

Description

  The present invention relates to a parallel unit control type DC power supply, and more particularly to a high speed parallel unit control type DC power supply using a limit circuit.

  Conventionally, when providing multiple types of DC power supply units corresponding to various power supply capacities as a series of product groups, the required number of small capacity power supply units as unit units is required according to the required power supply capacity. It has been performed that a plurality of units are connected in parallel to constitute a parallel unit type DC power supply.

  If the power supply unit serving as the unit unit is a power supply unit having the same configuration and the same capacity, it is advantageous to provide various types of DC power supply devices corresponding to different power supply capacities as a product group. (For example, refer to Patent Document 1 below).

Japanese Patent Laid-Open No. 06-070544

  However, such a conventional parallel unit type DC power supply device has the following problems in controlling individual power supply units connected in parallel as a variable power supply or a stabilized power supply.

  For example, as shown in FIG. 1, in a conventional parallel unit control type DC power supply device, three power supply units 1A, 1B, and 1C having the same power supply capacity connected in parallel to the rightmost load 4 share the load. Configured. Although not shown, each power supply unit is configured as a conventionally known switching power supply, and includes a smoothing circuit, a transformer, a DCDC control IC (not shown), and the like. In either case, power from an AC or DC power supply (not shown) is received, and a DC current output is supplied in parallel to the load 4 in accordance with a common control signal from the control board 2.

An error amplifier 3 is provided on the control board 2, and a control signal obtained by comparing the unit current average signal I _MON-AVE and the reference voltage V _REF is branched to control a plurality of power supply units 1A, 1B, 1C. It is the composition to do.

Here, the unit current average signal I _MON-AVE is the total of the measured values (output current values) I _MON-A , I _MON-B , and I _MON-C of the currents output from each power supply unit. In this case, it is a signal obtained by voltage-converting the value obtained by dividing by 3). The reference voltage V _REF is a voltage value set by a separate control logic or the like so that the output current required for the entire DC power supply device can be supplied.

  However, in the conventional parallel unit control type DC power supply device of FIG. 1, the current output from each power supply unit is controlled by the same control signal due to unavoidable variations in the components constituting each power supply unit. The value inevitably varies.

  This variation in the output of each power supply unit works synergistically, such as variations in the characteristics of the parts that make up each power supply unit, so in extreme cases, even if the DC power supply as a whole is in a low load situation, The load might concentrate only on a specific power supply unit. In such a case, only the specific power supply unit where the load is concentrated tends to increase heat generation, shortening its service life. In the worst case, the power supply unit may be broken. .

  FIG. 2 shows another conventional parallel unit control type DC power supply apparatus for solving such a conventional problem.

  In the conventional parallel unit control type DC power supply device of FIG. 2, for the sake of simplicity, a case where two power supply units 1A and 1B are connected in parallel is illustrated. In the conventional DC power supply device of FIG. 2, in order to reduce the load bias between the power supply units, each power supply unit is provided with a control circuit having an error amplifier, which is a two-stage master / slave control method. ing. In the case of FIG. 2, the power supply unit serving as the master is one power supply unit 1A, but a plurality of power supply units serving as slaves may be provided with the same configuration as the power supply unit 1B.

In the DC power supply device of FIG. 2, the control circuit 2A of the master power supply unit 1A has a control obtained by comparing the unit current average signal I _MON-AVE and the reference voltage V _REF with the error amplifier 3A as in FIG. The master power supply unit 1A is controlled by the signal. On the other hand, the control circuit 2B of the power supply unit 1B as a slave, compares the current measured output value I _MON-A of the power supply units 1A is a master, the power supply unit 1B own current output measured value I _MON-B with an error amplifier 3B Thus, another control signal is obtained to control the power supply unit 1B.

With such a configuration, the power supply unit 1B serving as a slave is controlled on the basis of the current output value I _MON-A of the power supply unit 1A serving as a master, so that it is controlled to always output the same current as the power supply unit 1A. The outputs of both power supply units can be evenly controlled without deviation.

However, in the conventional parallel unit control type DC power supply device of FIG. 2, the slave power supply unit 1B refers to the current output value of the master power supply unit 1A, and the signal path until the control signal is obtained. Becomes longer than the master power supply unit 1A. For this reason, for example, the response of the power supply unit 1B to the fluctuation of the unit current average signal I _MON-AVE becomes slower than that of the power supply unit 1A, and the transient load distribution is biased. In order to improve such response characteristics, this conventional DC power supply apparatus requires adjustment of the phase constant of each control circuit, and there is a problem that the control circuit becomes complicated.

  The present invention has been made in view of such problems, and the object of the present invention is to use a parallel unit control system that can perform uniform and high-speed operation without biasing the load between units by using a limit circuit. The object is to provide a DC power supply.

  In order to achieve such an object, the present invention basically has the following configuration.

  That is, in a DC power supply device of a parallel unit control system that controls a plurality of power supply units connected in parallel, a single control signal is obtained by comparing a unit current average signal obtained by averaging current values output from each power supply unit with a reference voltage. An error amplifier that outputs a signal, a branch connection portion that branches the single control signal output from the error amplifier to each power supply unit, and a control signal that is provided in each power supply unit and branched at the branch connection portion This is a parallel unit control type DC power supply device, characterized in that it has a limit circuit for limiting the power supply by a limit signal in each power supply unit.

  As described above, according to the present invention, by using the limit circuit, it is possible to realize a parallel unit control type DC power supply apparatus that can operate at high speed without uneven loads among the units.

It is a block diagram which shows the DC power supply device of the conventional parallel unit control system. It is a block diagram which shows another DC power supply device of another conventional parallel unit control system. It is a block diagram which shows the outline | summary of the direct-current power supply device of the high-speed parallel unit control system concerning embodiment of this invention. It is a block diagram which shows the detail of the direct-current power supply device of the high-speed parallel unit control system concerning embodiment of this invention. It is a figure explaining the detail of the limit circuit in embodiment of this invention, 2 examples. It is a block diagram which shows the detail of the circuit which detects the unit current average signal in embodiment of this invention.

  The present invention is obtained by comparing a unit current average signal and a reference voltage by one error amplifier provided on a common control board for a plurality of power supply units connected in parallel as in the conventional example of FIG. A basic configuration is assumed in which a single control signal is distributed and controlled to each power supply unit.

  In the present invention, in order to prevent a load bias between power supply units while ensuring high-speed operation without introducing a delay, a control signal branched to each power supply unit from one common error amplifier is used as a limit in the power supply unit. Each power supply unit is provided with a limit circuit that limits (clamps or clamps) by a signal.

  The limit signal in the limit circuit can be generated as a difference between a value obtained by adding a predetermined offset to the unit current average signal and the output current value in the power supply unit. By providing such a limit circuit for each power supply unit and limiting the control signal of each power supply unit, high-speed control can be realized while suppressing variations in load current between power supply units within a certain range. It becomes possible.

  By adopting such a configuration, in the present invention, any power supply unit can be controlled without introducing a delay in the generation of the control signal, so that a high-speed parallel unit control type DC power supply device can be realized. It is.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Outline of Embodiment of the Present Invention)
FIG. 3 is a configuration diagram showing an outline of a high-speed parallel unit control type DC power supply apparatus according to an embodiment of the present invention. In this embodiment, the case of two power supply units 1A and 1B is illustrated, but it goes without saying that three or more power supply units may be provided.

In the embodiment of FIG. 3, the unit current average signal I in one error amplifier 3 provided on the common control board 2 for the two power supply units 1 </ b> A and 1 </ b> B arranged in parallel with the load 4. _{The MON-AVE} is compared with the reference voltage V _REF , and the obtained single control signal is branched to control the two power supply units 1A and 1B.

The detailed configuration of the unit current average signal detection circuit that detects the unit current average signal I _MON-AVE in this embodiment will be described later.

  In the present embodiment, limit circuits 5A and 5B are provided for limiting the branched control signal with a limit signal in the power supply unit in order to achieve an even distribution of the load to each power supply unit. The output part of this limit circuit is connected to a control line for inputting a control signal branched to each power supply unit to a control input of each power supply unit.

  Although details are omitted in FIG. 3, a branch connection portion (a portion surrounded by a dotted line of the output of the error amplifier 3 in FIG. 3) that branches a single control signal of the output of the error amplifier 3 to the control input of each power supply unit is Even if the branched control signals are clamped by the limit circuit, it is necessary to prevent them from interfering with each other, and this is a connection part having a signal separation function.

  Although the detailed configuration of the limit circuits 5A and 5B will be described later, in FIG. 3, the limit circuit is expressed as operational amplifiers 6A and 6B and diodes 7A and 7B provided at the operational amplifier outputs.

The operational amplifiers 6A and 6B output a limit signal as a difference between a value obtained by adding a predetermined offset α to the unit current average signal I _MON-AVE and the output current values I _MON-A and I _MON-B of the power supply unit, respectively. .

    The diodes 7A and 7B are provided between the operational amplifier output and the control input of the power supply unit, and function as directional coupling elements that limit (limit) the branched control signal by comparing the limit signal and the branched control signal. .

  The diode of the limit circuit clamps the positive side of the control signal and displays the cathode (negative electrode) of the diode connected to the operational amplifier output, but it may be reversed depending on the signal polarity.

  With such a configuration, by setting the unit current average signal + arbitrary offset α as the reference value of the control signal limit, the power supply unit that attempts to flow a large amount of current operates the limit circuit and the control signal is clamped. The above output is not required.

  If the total output current is insufficient when the limit is applied, the power supply unit that is not clamped increases the output current, so the current required as a whole is maintained and the output of each power supply unit is balanced. It will be.

  The power supply unit on the clamp side has a larger output current than the other power supply unit that is not clamped, but the offset current does not affect the overall response time. It can be determined only by the error amplifier 3 on the control board 2, and high speed operation is possible.

(Details of the embodiment of the present invention)
FIG. 4 shows details of a high-speed parallel unit control type DC power supply apparatus according to an embodiment of the present invention.

  In FIG. 3, for simplicity, the limit circuits 5A and 5B include operational amplifiers 6A and 6B that output a difference between a value obtained by adding a predetermined offset α to the unit current average signal and an output current value in the power supply unit as a limit signal, a diode 7A, It was expressed in 7B.

  As shown in the detailed configuration of FIG. 4, the operational amplifiers 6A and 6B of the limit circuits 5A and 5B can be composed of two stages of first operational amplifiers 6A1 and 6B1 and second operational amplifiers 6A2 and 6B2.

The first operational amplifiers 6A1 and 6B1 include a unit current average signal (I _MON-AVE ) and an output current value in the power supply unit (signal I _MON-A on the power supply unit 1A side, and signal I on the 1B side). _MON-B ) difference. The second operational amplifiers 6A2 and 6B2 compare the first operational amplifier output with a predetermined offset voltage α and output it as a limit signal.

(Details of operation of embodiment)
Details of the operation in the embodiment of FIG. 4 will be described. For example, consider a case where the error signal output from the error amplifier 3 is branched and distributed to the two power supply units 1A and 1B as the same control signal.

Here, assuming that the output current from the power supply unit 1A is small and the output current of the power supply unit 1B is excessive, the diode 7B is turned on via the operational amplifiers 6B1 and 6B2 by the signal I _MON-B and is limited. The circuit 5B operates and the power supply unit 1B is clamped at the set limit current value.

After the power supply unit 1B is clamped, the unit current average signal (I _MON-AVE ) of the error amplifier 3 decreases if the output current of the entire DC power supply device seems to be insufficient. The control signal rises.

  Since the power supply unit 1B is already clamped, the output current of the power supply unit 1B remains unchanged even when the control signal rises, but the unclamped power supply unit 1A operates to flow a large amount of current.

  Therefore, both power supply units operate so as to output a balanced current, and the current balance is improved while maintaining the response performance.

In FIG. 4, the branch connection portion having the signal separation function is divided into two separation resistors R between the branch portion of the output of the error amplifier 3 and the connection portions of the limit circuits 5A and 5B and the control input of the power supply unit. _a, is realized by providing the R _B. By providing such a separation resistor at the branch connection part that branches the single control signal of the error amplifier output, even if one of the branched control signals is clamped, the other control signal is caused by the voltage drop of the separation resistor. Are not clamped and can separate signals so that they do not interfere with each other.

(Details of limit circuit)
FIG. 5 shows two examples of the detailed configuration of the limit circuit. The configuration shown in FIG. 5A shows details of the generation portion of the offset α of the limit circuit. The offset α of the limit circuit is generated as a voltage generated by a resistance voltage division of a predetermined voltage (for example, 15 V), and this can be applied to the positive side input of the second operational amplifier 6A2.

  Further, as shown in FIG. 5B, the second operational amplifier 6A2 of the limit circuit is fed back from the output side to the negative side input by a series circuit (time constant circuit) of the resistor R and the capacitor C. You can also. By doing in this way, the time from the detection of exceeding the threshold (offset α) to the clamping operation can be adjusted by the time constant CR.

  By providing such a time constant function in the limit circuit, the limit operation by the limit circuit is delayed by the time constant, but the response speed to the temporary output fluctuation is improved accordingly.

  In other words, by slowing the clamp timing so as not to affect the original response, there is no effect on transient control, ensuring high-speed operation, and applying a limit on a regular basis to equalize load distribution be able to.

(Unit current average signal detection circuit)
FIG. 6 shows details of a circuit for detecting the unit current average signal I _MON-AVE in the embodiment of the present invention.

As shown in FIG. 6, the output current of each power supply unit flowing through the current detection resistors R _SA and R _SB provided on the output side of each power supply unit is a current detection amplifier 8A having inputs connected to both ends of the current detection resistor. , 8B are detected as voltage signals and become measured values (output current values I _MON-A , I _MON-B ) of the output current of each power supply unit.

The detected measured values of the output current of each power supply unit are summed by the average amplifier 9 and divided by a predetermined magnification (in this case, 2) to become a unit current average signal (I _MON-AVE ). The signal is input to the error amplifier 3 and compared with a predetermined reference voltage V _REF .

  As described above, the technical idea of the present invention is not limited to the configuration of the above embodiment. For example, as described above, in the description of the embodiment, the power supply unit has two parallel connections of 1A and 1B. Obviously, it is also possible.

  With such a configuration of the present invention, it is possible to realize a high-speed parallel unit control type DC power supply device without uneven loads among the units.

1A, 1B, 1C Power supply unit 2, 2A, 2B Control board (control circuit)
3, 3A, 3B Error amplifier 4 Load 5A, 5B Limit circuit 6A, 6B, 6A1, 6A2, 6B1, 6B2 Operational amplifier 7A, 7B Diode (directional coupling element)
8A, 8B Current detection amplifier 9 Average amplifier R _A , R _B separation resistance R _SA , R _SB current detection resistance R, C Time constant resistance and capacitor

Claims (7)

In a DC power supply device of a parallel unit control system that controls a plurality of power supply units connected in parallel,
One error amplifier that outputs a single control signal by comparing a unit current average signal obtained by averaging current values output from each power supply unit with a reference voltage;
A branch connection portion for branching the single control signal output from the error amplifier to each power supply unit;
A parallel unit control type DC power supply apparatus comprising a limit circuit provided in each power supply unit and configured to limit a control signal branched at the branch connection portion by a limit signal in each power supply unit. The DC power supply device according to claim 1, wherein the limit circuit is
An operational amplifier that outputs the limit signal as a difference between a value obtained by adding a predetermined offset to the unit current average signal and a current value output by each power supply unit,
A parallel unit control type DC power supply comprising a directional coupling element provided at an output of the operational amplifier and configured to limit the branched control signal by comparing the limit signal and the branched control signal. apparatus. The DC power supply device according to claim 2, wherein the operational amplifier of the limit circuit is
A first operational amplifier that takes a difference between the unit current average signal and the output current value of the power supply unit;
A parallel unit control type DC power supply device comprising a second operational amplifier that compares the output of the first operational amplifier with a predetermined offset voltage and outputs the limit signal. 4. The DC power supply device according to claim 3, wherein the second operational amplifier is
A parallel unit control type DC power supply device comprising a time constant circuit that feeds back from an output side to a negative side input. In the DC power supply device according to any one of claims 2 to 4,
The directional coupling element includes a diode, and a parallel unit control type DC power supply. In the direct-current power supply device according to any one of claims 1 to 5,
The branch connection portion is a connection portion having a separation resistor provided between the output of the error amplifier and the connection portion of each limit circuit and the control input of the power supply unit. Type DC power supply. In the direct-current power supply device according to any one of claims 1 to 6,
The unit current average signal is a signal obtained by detecting a current value output from each power supply unit as a voltage signal by a current detection amplifier, summing them by an average amplifier, dividing the result by a predetermined magnification, and averaging the parallel signals. Unit control DC power supply.

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