JPH065965B2 - DC power supply - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a DC power supply device for redundantly operating a plurality of DC conversion units that perform AC-DC conversion or DC-DC conversion. The present invention relates to a DC power supply device that keeps the load sharing of the output of a DC conversion unit even.

(Problems to be Solved by the Prior Art and Invention) By operating a plurality of AC-DC conversion units or DC-DC conversion units that perform DC-DC conversion in parallel, the total power capacity capable of supplying power is increased, There is a method in which the DC conversion units are operated in parallel, that is, the redundant parallel operation is performed to enhance the reliability of the power supply device.

FIG. 6 is a block diagram showing a conventional DC power supply device. In the figure, M1, M2 and M3 are DC conversion units that perform AC-DC conversion or DC-DC conversion. The case of parallel operation by three DC conversion units M1, M2, and M3 is shown. DC conversion units M1, M2, M
The inputs and outputs of 3 are commonly connected to inputs A and B, respectively.

AC or DC power is received at the input A, converted into a DC voltage by each DC conversion unit M1, M2, M3, and a current is supplied from the output B to the load. The supervisory control circuit SV has the functions of a monitor and display circuit for the operating states and voltages of the DC conversion units M1, M2, M3. Terminals FA1, FA of each DC conversion unit M1, M2, M3
2, Receive the signal of operating condition from FA3.

The DC conversion units M1, M2, M operating in parallel
In order for the respective output currents of 3 to flow evenly, it is necessary to match the values of the DC voltage of the outputs of the DC conversion units M1, M2, M3. If there is a difference in the output voltage value, the sharing of the output current of each DC conversion unit M1, M2, M3 changes remarkably, and only a specific DC conversion unit is always overloaded. Therefore, the DC conversion unit M1,
It is necessary to equalize the output currents of M2 and M3,
Conventionally, a method of setting the output voltage with high accuracy has been performed. Specialized operator is DC conversion unit M1, M2
By setting the output voltage of M3 with high accuracy, the output currents of the DC conversion units M1, M2, M3 are shared depending on the output characteristics of each DC conversion unit.

However, in this case, it is unavoidable that the distribution of the output current varies due to variations due to the setting method and variations in the output characteristics among the DC conversion units M1, M2, and M3. As a result, the DC conversion unit M1, M2 or M
Among the three, the temperature rise of the DC conversion unit whose load sharing is large becomes large. Further, when the DC conversion unit having a large load sharing is selectively cut off due to an accident or the like, the output voltage fluctuates greatly. Further, there is a drawback that the operator needs to readjust the output voltage in order to equalize the load sharing at the time of replacement of the DC conversion unit, which imposes restrictions on improvement of maintainability and reliability.

(Object of the Invention) It is an object of the present invention to provide a DC power supply device in which the above-mentioned drawbacks are improved. That is, it is to automatically perform load sharing during parallel operation, eliminate the need for highly accurate adjustment by the operator, which was required in the past, and improve maintainability and reliability. Therefore, check the number of operating DC conversion units operating in parallel, receive a signal of the total output current of the DC power supply device, and set the load sharing command device that commands the value of the output current to be shared by each DC conversion unit. The DC conversion unit operates so as to equalize the output currents by the load sharing command signal from the load sharing command device.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a DC power supply device in which a plurality of DC conversion units performing AC-DC conversion or DC-DC conversion are operated in parallel. A current detector for detecting the total output current, an output from the current detector is given, and a signal from the load sharing command device for calculating an output current value to be shared by the DC conversion unit, and a signal from the load sharing command device. A load conversion command device for converting the signal from the current detector into a digital signal; and a signal from the AD converter. Receiving a signal indicating the operating status of the DC conversion unit, calculating the output current to be shared by each DC conversion unit, and loading the DC conversion unit A microprocessor for outputting a sharing command signal, the DC conversion unit receives an output signal from the load sharing command device,
A current limiting circuit that limits the output current of the DC conversion unit that should share the load; and a signal from the current limiting circuit,
And a current comparison unit that compares the signal with the output of the DC conversion unit, a control unit that controls the output voltage to be constant by the signal from the current comparison unit and the output voltage signal of the DC conversion unit, and the control unit The main point of the invention is a DC power supply device characterized in that it is provided with a main circuit section that operates by a signal.

(Operation) In the present invention, by providing the load sharing command device and the DC conversion unit, even if the output voltage is not adjusted with high accuracy, it is possible to automatically perform load sharing evenly by the command of the load sharing command device. This is performed by a microprocessor, and has the effect that readjustment is not necessary even if the DC conversion unit is replaced.

(Example) Next, the Example of this invention is described.

FIG. 1 is a block diagram showing the configuration of a DC power supply device of the present invention.

M1 to M3 are DC conversion units, LS is a load sharing command device, SV is a monitoring control unit, A is an input terminal, B is an output terminal,
C indicates a current detector.

The figure shows an example of a DC power supply device in which three DC conversion units are operated in parallel. The input terminals a1, a2, a3 of the DC conversion units M1, M2, M3 and the output terminals b1. b2. b
3 are commonly connected to the input A and the output B, respectively. The load sharing command device LS receives a signal of the total output current of the device at the terminal R from the current detector C. Further, the load sharing command device LS is a DC conversion unit M1, M2, M3.
The terminals FA1, FA2, FA3 receive the signals of the operating states of the DC conversion units M1, M2, M3.
From the terminal LA of the load sharing command device LS, the current limiting circuit LM built in the DC conversion units M1, M2, M3
A load sharing command signal is commonly sent to the terminals L1, L2 and L3 of 1, LM2 and LM3. Load sharing command device LS
Check the number of DC converter units that are operating normally. Then, the total output current value of the DC power supply device is recognized. Letting TP be the recognized total output current and N the number of operating DC conversion units, the value TM of the current to be shared by each DC conversion unit M1, M2, M3 is calculated.

K is a coefficient and is a value that includes a margin of variation in the output currents of the DC conversion units M1, M2, M3.
Is about 1.2. This value is sent as a load sharing command to each of the DC conversion units M1, M2, M3, and is controlled so as to be equal to or less than the current value of this value to equalize the shared current. If only one DC conversion unit is operating, the load sharing command signal is unnecessary and is not sent. In addition, the value of the total output current of the DC power supply device is the DC conversion units M1, M
If the rated currents of M2 and M3 are small, the DC conversion units M1, M2, and M3 are light loads, and it is not necessary to perform equalization. Therefore, the load sharing command signal is not transmitted.

It goes without saying that even if the number of DC converter units operating in parallel is four or more, the load sharing command device can similarly issue a load sharing command to equalize the output currents.

FIG. 2 is a block diagram of a DC conversion unit M1 having a load sharing command device LS and a current limiting circuit LM, which is a part of the present invention, and is shown together with a current detection unit C for detecting the total output current value of the DC power supply device. is there.

In the figure, C is a current detector, which detects the total output current of the DC power supply device.

The block LS is a load sharing command device. MP indicates a microprocessor, and this microprocessor M
P is a clock pulse oscillator CK, a memory ME, and an A / D
The converter AD, the D / A converter DA, and the tristate buffer TB are connected.

In this description, the case where three DC conversion units are operated in parallel is shown.

R is an input terminal for the output current signal sent from the current detector C. LA is each DC conversion unit M1, M2, M
The terminals connected to the terminals L1, L2, and L3 of the DC converter unit M1 of the load sharing command device LS.
It is an output terminal for calculating an output current value to be shared by M2 and M3 and transmitting a command signal of the current value to be shared. P1,
P2 and P3 are DC conversion units M1 that are operating in parallel
It is an input terminal for receiving a signal of the operating state of M2 or M3, and the terminals are provided as many as the number of DC conversion units operating in parallel. A signal of the total output current of the DC power supply device is received from the input terminal R to recognize the load state.

From the input terminals P1, P2, P3, the number of operating units is recognized by receiving signals of operating states of the DC conversion units M1, M2, M3 operating in parallel. Microprocessor MP is A / D
The output current value to be shared by each DC conversion unit is calculated from the signal from the converter and the signal indicating the operating condition of the operating DC conversion unit. The result is output from the microprocessor MP and converted into analog by the D / A converter DA. A load sharing command signal is output from the output terminal LA to each DC conversion unit M1, M2, M3 to equalize the output current of each DC conversion unit.

In the figure, a block M1 is a DC conversion unit, and is composed of a current limiting circuit LM and a main circuit unit MC, a control unit CT, a current comparison unit CP, and a sequence unit SE which are general configurations of the DC conversion unit.

In the DC conversion unit, a1 is an input voltage terminal, b1
Is an output voltage terminal. L1 is an input terminal for a load sharing command signal sent from the load sharing command device LS. FA1
Is an output terminal for sending the operating state of the DC conversion unit M1 from the sequence section SE of the DC conversion unit to the load sharing command device. The DC conversion unit M1 sends the input voltage from the terminal a1 to the main circuit unit MC. The control unit CT receives a voltage feedback signal from the output of the main circuit unit MC and a current feedback signal via the current comparison unit CP, and performs operations of stabilizing the output voltage and limiting the output current to a certain value or less.

Receives the load sharing command signal from the terminal LA and receives the current limiting circuit L
Give to M. The current limiting circuit LM gives a signal for limiting the output current to the current comparison unit CP according to the value of the command signal. The current comparison unit CP is operated so that the reference value of the current limit becomes the value of the command signal, and the output signal of the CP is changed to the control unit CT.
Then, by controlling the main circuit section MC, the output currents of the respective DC conversion units are equalized.

The DC conversion units M2 and M3 are the same DC conversion units as the DC conversion unit M1.

In FIG. 2, the microprocessor MP has been described as being dedicated to the load sharing command device. However, information processing other than the load sharing command, such as providing a sequence function at the time of starting the DC conversion unit, diagnosing sequence operation, operation management, etc. It can also be used as a control unit of a DC power supply device.

3 and 4 are circuit examples of the embodiment shown in FIG. An example of the program flow chart is shown in FIG. In the load sharing command device of FIG. 3 and the flow chart of FIG. 5, signals of operating states are obtained from the DC conversion units M1, M2, M3 operating in parallel at terminals P1, P2, P3. This signal is applied to resistors R1, R2 and R
3, R4, R5, R6 and photocouplers PC1, PC2
Insulation is separated by PC3. Outputs from the photocouplers PC1 to PC3 are connected to resistors R7, R8, R9 and capacitors C1, C
2, C3 and buffers A1, A2, A3, and waveform shaping is performed by a waveform shaping circuit. The output of the microprocessor MP is selected by the instruction of the microprocessor MP, and the output of the microprocessor MP is transferred through the tristate buffer TB.
Send to. Based on the signal, the microprocessor MP recognizes the number of DC conversion units operating in parallel and sets the number to N (FIG. 5,).

A signal of the total output current value of the DC power supply device from the current detector C is input to the input terminal R. The signal of this current value is A /
It is converted into a digital value by the D converter AD. This digital amount is stored in the memory ME, and its value is designated as TP (FIG. 5). The following calculation is performed by the microprocessor MP K is a coefficient, and TM is a value of output current to be shared by each DC conversion unit (Fig. 5). Next, N ≧ 2 (2) TM ≧ TU × α (3) TU is a value representing the rated current of the DC conversion unit. α
Is a coefficient, and is normally set to about 0.1 so that the load sharing command is not issued when the total output current is small. When the above calculation results (2) and (3) are established (Fig. 5), a command signal for load sharing is issued from the microprocessor MP, and D / A
The converter DA converts the analog signal, the operational amplifier A4 and the resistors R10 and R11 amplify the amplified signal, and the output terminal LA outputs the signal as a load sharing command signal for the DC conversion unit (FIG. 5). CK is a clock pulse oscillator for the reference signal of the microprocessor MP.

FIG. 4 is a detailed block diagram of the DC conversion unit M1.

The sequence section SE (see FIG. 2) controls the operation and stop of the DC conversion unit, and the relay contact R during normal operation.
Turn Y on. The output terminal of the relay contact is FA. This signal is input to the load sharing command device LS as an operation signal of the DC conversion unit.

A load sharing command signal is input to the terminal L from the load sharing command device LS. The signals are transferred to resistors R1, R2, R3, smoothing capacitor CF1, reverse blocking diode D1, and operational amplifier A.
A comparison signal is created by the current limiting circuit LM composed of 1 and is input to the current comparison unit CP.

The current comparison unit CP includes resistors R4, R5, R6, R7, R
8, R9 and operational amplifier A2. The current limiting circuit LM having a value obtained by dividing the voltage + V by the resistors R4 and R5.
Match the outputs of and use as the reference for the output current. This reference and the signal obtained by converting the output current of the DC conversion unit into the output current signal by the current detector CU are error-amplified by the operational amplifier A2, and a signal for making the output current of the DC conversion unit constant is output to the control unit.

The control unit CT outputs a signal for controlling the main circuit unit MC from the output voltage signal of the main circuit unit MC and the signal of the current comparison unit.
Output to C.

The main circuit unit MC is a main circuit of a DC conversion unit that converts the input voltage of the input terminal a into a stable DC voltage according to a signal from the control unit CT.

(Advantages of the Invention) As described above, according to the present invention, in the parallel operation state of a plurality of DC conversion units, by instructing the current value to be shared to each DC conversion unit from the load sharing command device, The output current of each DC conversion unit can be equalized. As a result, highly accurate adjustment by a specialized operator is eliminated in order to equalize the load sharing during parallel operation. Further, it is possible to equalize the temperature rise of the heat generating components of the DC conversion unit, and it is possible to obtain the effect of contributing to the improvement of maintainability and reliability.

[Brief description of drawings]

FIG. 1 is a block diagram of a DC power supply device according to an embodiment of the present invention, FIG. 2 is a block diagram illustrating the operation of the present invention, and FIG.
FIG. 4 and FIG. 4 are diagrams showing a concrete circuit example of FIG. 2, FIG. 5 is a diagram showing a flowchart example, and FIG. 6 is a block diagram of a conventional DC power supply device. M1, M2, M3 ... DC conversion unit LM1, LM2, LM3 ... Current limiting circuit C ... Current detector LS ...・ Load sharing command device SV ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Supervisory control unit

Claims (1)

[Claims] 1. A direct current power supply for operating a plurality of direct current conversion units that perform alternating current-direct current conversion or direct current-direct current conversion in parallel, a current detector for detecting a total output current of the direct current power supply device, and the current detector. The load sharing command device for calculating the output current value to be shared by the DC conversion unit and the signal from the load sharing command device, and the DC conversion unit for limiting the output current by the signal. The load sharing command device includes an AD converter that converts a signal from the current detector into a digital signal, a signal from the AD converter, and a signal indicating an operating status of the DC conversion unit, and receives the respective DC signals. The conversion unit is provided with a microprocessor that calculates an output current to be shared and outputs a load sharing command signal to the DC conversion unit. The DC conversion unit receives the output signal from the load sharing command device, receives a signal from the current control circuit that limits the output current of the DC conversion unit that should share the load, and receives the signal from the DC conversion unit. A current comparison unit that compares the output of the unit, a control unit that controls the output voltage to be constant by the signal from the current comparison unit and the output voltage signal of the DC conversion unit, and a main circuit that operates by the signal of the control unit And a DC power supply device.