JP3268482B2 - Power supply - 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 supply device having a function of operating a plurality of converters for driving a load in parallel and redundantly.

[0002]

2. Description of the Related Art A conventional power supply of this type is disclosed in
No. 928 and Japanese Patent Application Laid-Open No. 58-198122 are known.

[0003]

The above conventional power supply device controls the current balance and current sharing of the converters operated in parallel by detecting the output current value of each converter and calculating the average of the output current value of the converter. This is an average current control method to be combined.

However, in the average current control system, when a certain converter fails, the output current of that converter becomes zero, so that the average current value of all converters decreases. Since the current of each converter decreases where the power must be increased, the current amount required by the load cannot be supplied. In order to solve this, a device that detects a failed converter, disconnects it from the parallel operation with a switch or the like, and distributes the output current value of the remaining converters to match the load is required.

A conventional maximum current control system for detecting the output current value of each converter and adjusting the output current of the converter to the maximum value as a control method of current balance and current sharing of converters operated in parallel in a conventional power supply device. There is also.
However, this conventional technique requires an operational amplifier and the like, and has a problem that the circuit configuration is complicated and expensive.

The present invention has been made in view of such circumstances, and provides a plurality of converters operating in parallel with redundancy, and detects a failed converter and disconnects it from the parallel operation by a switch or the like. It is an object of the present invention to provide a small power supply device that does not require such a device and has a simple circuit configuration.

[0007]

A power supply apparatus according to the present invention comprises a plurality of converters each having a voltage control circuit for detecting an output voltage and controlling the output voltage based on the detected output, and performing redundant operation in parallel to supply power to a load. A power detector that is connected in series to the secondary side of a transformer provided on the AC input side of each converter and detects the output current of the converter, and captures the detection output of the current detector. A self-current detection circuit that outputs the detection output as a voltage as a detection output of the own converter, and a detection output of the current detector, and compares the detection output with a detection output of an output current of another converter to obtain a maximum current. A maximum current detection circuit that outputs an output current value of a converter that outputs a value as a detection value, an output of the self-current detection circuit and a negative output of the maximum current detection circuit, and the addition is performed. Have a current control circuit configured to force and a summing means for supplying the detection system of the voltage control circuit
The maximum current is supplied to the self-current detection circuit of each converter.
It is characterized in that the flow detection circuits are connected in series with opposite polarities .

[0008]

[0009] power supply of the present invention, detects an output voltage
A voltage control circuit for controlling an output voltage based on the detected output.
Load with multiple converters with parallel paths
Power supply to supply power to
Connected in series to the secondary side of the transformer provided on the
A current detector for detecting an output current of the converter;
The detection output of the current detector is captured, and the detection output is
Self-current detection circuit that outputs voltage as the detection output of the barter
And the detection output of the current detector.
Compare the output with the detected output of the output current of the other converter,
Detects the output current value of the converter that outputs the maximum current value
A maximum current detection circuit that outputs as
The output of the circuit and the negative output of the maximum current detection circuit are added, and
An adder that supplies an addition output to a detection system of the voltage control circuit.
And a current control circuit including a stage, wherein the maximum current detection circuit is connected in parallel to the self-current detection circuit of each converter via a resistor, with the polarity of the maximum current detection circuit being reversed.

In the power supply unit according to the present invention, the current detector is a current transformer.

[0011]

In the power supply device having the above structure, for example, as shown in FIG. 2, a current detection circuit 10 for detecting the output current of the converter is connected in series to the secondary side of the transformer T1 of each converter. The detection output is connected so as to be supplied to the maximum current detection circuit 14 and the self-current detection circuit 12.

Each maximum current detection circuit of each converter operated in parallel is connected via a control line CL so that the output of the self-current detection circuit 12 and the negative output of the maximum current detection circuit 14 are added in each converter. Connected so that the added output is applied to the voltage control circuit of the converter.

Each converter is controlled so that the output current value matches the output current value of the converter that outputs the maximum current. Each converter is controlled to match the largest output current value of the converters operated in parallel, the output current of the converter with the smaller output current increases, and as a result, the output current of the converter with the larger output current decreases. The output current of each converter is balanced.

Therefore, if the number of converters operated in parallel is increased by one or two with respect to the load capacity, even if a certain converter fails and the output current becomes zero, the failed converter is affected. Instead, the load current can be shared by the remaining converters. Therefore, a stable current balance control can be performed for each converter without the need for a failure detection of each converter or a changeover switch.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of an embodiment of the power supply device according to the present invention. The converter of this embodiment is a forward type DC / DC converter. In the figure, the primary side of a transformer T1 is connected to DC voltage terminals 1 and 2 via a switching element Q1.

The gate of the switching element Q1 is P
It is connected to the secondary side 5B of the photocoupler via the WM control circuit 7.

On the other hand, one end on the secondary side of the transformer T1 is grounded via a diode D1, an inductance L1, and a capacitor C1.

Further, a diode D2 is connected in parallel with the series circuit of the capacitor C1 and the inductance L1 with the illustrated polarity. With such a configuration, the AC voltage obtained on the secondary side of the transformer T1 is rectified and smoothed by the diodes D1, D2, the inductance L1, and the capacitor C1 by turning on and off the switching element Q1, and the DC voltage is applied across the capacitor C1. Is obtained. The following voltage control circuit is configured to control this DC voltage to a constant voltage.

The voltage control circuit is connected in parallel with the capacitor C1,
A series circuit including the resistor R4, the photocoupler 5A, and the three-terminal regulator 6 and a series circuit including the resistors R1, R2, and R3 are connected. A connection point A between the resistors R1 and R2 is connected to the control terminal of the three-terminal regulator 6. It is configured.

A diode D3 connected between the resistor R1 and the output terminal 3 is provided to prevent a current from flowing backward when a certain converter fails when a plurality of converters are operated in parallel. I have.

The voltage control circuit operates as follows. That is, for example, when the terminal voltage of the capacitor C1 decreases, the voltage at the connection point A between the resistors R1 and R2 decreases, and the control terminal voltage of the three-terminal regulator 6 also decreases. The current flowing decreases, and the current flowing between the photocouplers 5A and 5B also decreases. As a result, the on / off duty of the gate pulse output from the PWM control circuit 7 is increased to increase the secondary voltage of the transformer T1, thereby suppressing a decrease in the terminal voltage of the capacitor C1.

On the other hand, when the terminal voltage of the capacitor C1 is about to rise, the voltage control circuit operates in the reverse manner to reduce the on / off duty of the gate pulse of the PWM control circuit 7, and the terminal of the capacitor C1. Control is performed so that the voltage is suppressed from rising and becomes a constant voltage.

In the power supply device according to the present invention, a current control circuit described below is added to this voltage control circuit.

The current control circuit includes a current detector 10 for detecting an alternating current on the secondary side of the transformer T1, a self-current detection circuit 12, a maximum current detection circuit 14, an output of the self-current detection circuit 12, and a maximum current. And an adder circuit 16 for calculating a difference between the output from the detection circuit 14 and the output from the detection circuit 14.

The current control circuit supplies an output of a current detector 10 for detecting an alternating current on the secondary side of the transformer to a self-current detection circuit 12 and a maximum current detection circuit 14.

The maximum current detecting circuit 14 has a control line CL, and is connected to another converter (not shown) during the parallel operation via the control line CL. The maximum current detection circuit 14 operates so as to output, as a voltage, the larger one of the maximum value of the output current of another converter obtained via the control line CL and the detection output of the current detector 10.

Next, the adder circuit 16 includes the self-current detection circuit 1
2 and the output of the maximum current detection circuit 14 are compared and subtracted, and the result is used as a resistor R constituting a voltage control circuit.
The voltage is applied to the connection point B between R2 and R3.

With this configuration, for example, when the output current value of this converter is smaller than the output current value of another converter, the output voltage of the maximum current detection circuit 14 becomes larger than the output voltage of the self-current detection circuit 12, As a result, the voltage at the connection point B between the resistors R2 and R3 constituting the voltage control circuit decreases. Therefore, the voltage control circuit uses the resistor R
It is determined that the voltage at the connection point A between 1 and R2 has decreased, and the voltage between both ends of the capacitor C1 increases. As a result, the output current value of this converter also increases and approaches the output current value of another converter, The output current of each converter is balanced.

Next, FIG. 2 shows the configuration of another embodiment of the power supply device according to the present invention. This embodiment specifically shows a circuit configuration for subtracting the output voltage of the self-current detection circuit 12 and the output voltage of the maximum current detection circuit 14 in the embodiment shown in FIG. In the figure, the output terminal 4 of the converter
(Ground) and the connection point B between the resistors R2 and R3.
10, the output Vj of the self-current detection circuit 12 is connected in series so that the output Vj of the self-current detection circuit 12 and the negative output Vm of the maximum current detection circuit 14 are added.
This is an example in which the output Vm of the maximum current detection circuit 14 is subtracted from. Further, a control line CL is extracted from a connection point between the maximum current detection circuit 14 and the self-current detection circuit 12.

The maximum current detection circuit 14 outputs, as a voltage, the larger of the output current value obtained from the other converter and the output current value obtained from the current detector 10 of the own converter via the control line CL during the parallel operation. To work.

In this configuration, when the own converter is outputting the maximum current, the output Vm of the maximum current detection circuit 14 is equal to the output Vj of the self-current detection circuit 12, so that the voltage applied to the connection point B between the resistors R2 and R3 is Since it is zero, the operation of the voltage control circuit is not affected by the operation of the current control circuit and there is no voltage fluctuation.

However, when the other converter is outputting the maximum current, the output Vm of the maximum current detection circuit 14 is higher than the output Vj of the self-current detection circuit 12, so that the resistors R2 and R2
3, the voltage applied to the connection point B becomes a negative voltage. The operation of the voltage control circuit increases the voltage across the capacitor C1 under the influence of the operation of the current control circuit, and the value of the output current of this converter also increases. As a result, the output current values of the other converters are approached, and the output currents of the converters are balanced.

With the above-described operation, even if one converter fails and the output becomes zero while a plurality of converters are operating in parallel, the current control circuit determines that the converter with the lower output current is not used for another converter. The converter is configured so as not to cause any influence, and the diode D3 is provided on the output side of the converter, so that the reverse current of the current is prevented, and the faulty converter is detected and is disconnected from the parallel operation by a switch or the like. A simple converter that does not require such a device can be configured.

Further, a current control circuit can be constituted by a simple circuit including only a current transformer, a capacitor, a resistor and a diode without using an expensive and complicated circuit such as an operational amplifier.
A small converter with a simple circuit configuration can be obtained. By performing the redundant redundancy operation of the converter having the above configuration in parallel with the number of converters capable of supplying a current larger than the load capacity, a highly reliable redundant operation can be performed.

Next, FIG. 3 shows the configuration of another embodiment of the power supply unit according to the present invention. In this embodiment, a maximum current detection circuit 14 via a resistor R12 and a self-current detection circuit 12 via a resistor R11 are connected in parallel between the output terminal (ground) 4 of the converter and a connection point B between the resistors R2 and R3. This is an example in which the output Vj of the self-current detection circuit 12 and the negative output −Vm of the maximum current detection circuit 14 are added. Further, the control line CL is taken out from the opposite side of the maximum current detection circuit 14 from the ground.

The maximum current detection circuit 14 uses the larger one of the output current value obtained from the other converter and the output current value obtained from the current detector 10 of the own converter as a voltage during the parallel operation through the control line CL. Operate to output. In this configuration, when the own converter is outputting the maximum current, the outputs Vm of the maximum current detection circuit 14 and the output Vj of the self-current detection circuit 12 are equal.
Is zero, the voltage control circuit is not affected by the operation of the current control circuit, and there is no voltage fluctuation.

However, when the other converter is outputting the maximum current, the output Vm of the maximum current detection circuit 14 is higher than the output Vj of the self-current detection circuit 12, so that the resistors R2 and R3
3, the voltage applied to the connection point B becomes a negative voltage, and the voltage control circuit is affected by the operation of the current control circuit.
Operates to increase the voltage between both ends.

FIG. 4 shows a specific configuration of the current control circuit in the converter shown in FIG. In the figure, a primary coil 20A of a current transformer 20 is connected in series between a transformer T1 and a ground GND, and one end of one secondary coil 20B of the current transformer 20 is connected to a control line CL.
I and a capacitor C1 through a diode D11.
1 and a resistor R14 are connected in parallel.

The positive electrode of the capacitor C11 is connected to a resistor R1.
0 is connected to point B in FIG. The circuit including the diode D11, the capacitor C11, and the resistor R14 indicated by the broken line is the self-current detection circuit 12 illustrated in FIGS.

On the other hand, a parallel circuit consisting of a capacitor C10 and a resistor R13 is connected between one end of another secondary coil 20C of the current transformer 20 and the control line CLI via a diode D10. The positive electrode is connected to the ground GND via a diode D12. The circuit indicated by the broken line including the diode D10, the capacitor C10, the resistor R13, and the diode D12 is the maximum current detection circuit 14 illustrated in FIGS.

The maximum current detection circuit 14 detects the larger one of the output current value obtained from another converter via the control line CL1 and the output current value obtained from the current transformer 20 as the current detector of the converter during the parallel operation. It operates to output a value as a voltage.

In the above configuration, when the current flowing on the secondary side of the transformer T1 changes, a voltage proportional to the current is generated in the secondary coils 20B and 20C of the current transformer 20. This voltage is rectified and smoothed by the self-current detection circuit 12 and the maximum current detection circuit 14, respectively, to obtain the output Vm of the maximum current detection circuit 14 and the output Vj of the self-current detection circuit 12, and obtain the output Vj of the self-current detection circuit 12. The result of adding the negative output -Vm of the maximum current detection circuit 14 is added between the ground of the voltage control circuit and the point B.

As described with reference to FIGS. 1 and 2, when the converter is outputting the maximum current, the maximum current detection circuit 14
Is equal to the output Vj of the self-current detection circuit 12, the voltage applied to the connection point B between the resistors R2 and R3 in FIG. 2 is zero, and the operation of the voltage control circuit is not affected by the operation of the current control circuit. No voltage fluctuation.

However, when the other converter is outputting the maximum current, the output Vm of the maximum current detecting circuit 14 is higher than the output Vj of the self-current detecting circuit 12, so that the resistors R2 and R3
3, the voltage applied to the connection point B becomes a negative voltage, and the operation of the voltage control circuit increases the voltage across the capacitor C1 under the influence of the operation of the current control circuit, and the output current value of the own converter also increases. The output currents of the other converters approach, and the output currents of the respective converters are balanced.

Since the operation described above is performed, even if one converter fails and the output becomes zero during the parallel operation of a plurality of converters, the current control circuit determines that the converter with the lower output current is able to operate with the other converter. The converter is configured so as not to have an influence, and the diode D3 is provided at the output terminal of the converter, so that the backflow of the current from the load side can be prevented, and the failed converter like the conventional power supply is detected. Thus, a simple converter that does not require a device for disconnecting it from parallel operation with a switch or the like can be configured.

Further, a current control circuit can be constituted by a simple circuit including only a current transformer, a capacitor, a resistor, and a diode without using an expensive and complicated circuit such as an operational amplifier.
In particular, by using a current transformer for insulation, a small converter with a simple circuit configuration can be obtained. A redundant operation with high reliability can be performed by performing a parallel redundant operation of a number of converters capable of supplying a current larger than the load capacity in the converter configured as described above.

Next, FIG. 5 shows another embodiment of the current control circuit in the power supply device shown in FIG. The present embodiment is an example in which the secondary coil of the current transformer 20 is configured as one. The capacitor C12 and the resistor R15 are connected between one end of the secondary coil 20D of the current transformer 20 and the control line CLI via a diode D14. Are connected in parallel. Thereafter, the circuit is configured to be divided into a maximum current detection circuit 14 and a self-current detection circuit 12 indicated by broken lines.

The self-current detecting circuit 12 includes a capacitor C12
A parallel circuit comprising a capacitor C11 and a resistor R14 is connected to both ends of the device via a diode D11 to form a configuration as shown by a broken line in the figure. The resistor R10 is connected from the positive electrode side of the capacitor C11.
Is connected to the connection point B between the resistors R2 and R3 in FIG.

The maximum current detecting circuit 14 has a capacitor C12 connected to both ends of the capacitor C12 via a diode D10.
A parallel circuit consisting of a resistor 10 and a resistor R13 is connected to form a configuration as shown by a broken line in the figure.

Further, the positive electrode of the capacitor C10 is connected to the ground GND, and the negative electrodes of the capacitors C12, C10 and C11 are connected to the control line CL1.

The maximum current detection circuit 14 detects the larger one of the output current value obtained from another converter via the control line CL1 and the output current value obtained from the current transformer 20 as the current detector of the own converter during the parallel operation. It operates to output a value as a voltage. Therefore, the operation of the current control circuit is similar to that of the current control circuit shown in FIG.
When the other converter is outputting a larger current than the own converter, the output Vm of the maximum current detection circuit 14 is higher than the output Vj of the self current detection circuit 12, so that the resistors R2 and R3
Becomes negative voltage, the operation of the voltage control circuit increases the voltage across the capacitor C1 under the influence of the operation of the current control circuit, and the output current value of this converter also increases. Approaching the output current value of the converter of
The output current of each converter is balanced.

FIG. 6 shows another embodiment of the current control circuit in the power supply device shown in FIG. In the present embodiment, a diode D14, a capacitor C12, a resistor R
15 is omitted. In the figure, a self-current detection circuit 12 is connected to a parallel circuit composed of a capacitor C11 and a resistor R14 via a diode D11 between both ends of a secondary coil 20D of a current transformer 20, and is configured as shown by a broken line in the figure. The capacitor C11 is connected from the positive electrode side to the connection point B between the resistors R2 and R3 in FIG. 2 via the resistor R10.

The maximum current detecting circuit 14 includes a diode D across the secondary coil 20D of the current transformer 20.
10, a parallel circuit composed of a capacitor C10 and a resistor R13 is connected to form a configuration as shown by a broken line in the figure. The positive electrode of the capacitor C10 is connected to the ground GND via the resistor R16, and the negative electrodes of the capacitors C10 and C11 are connected to the control line CL1.

The maximum current detection circuit 14 determines the larger one of the output current value obtained from another converter via the control line CL1 and the output current value obtained from the current transformer 20 as the current detector of the own converter during the parallel operation. It operates to output a value as a voltage. Therefore, as in the current control circuit shown in FIG. 5, when another converter outputs a larger current than its own converter, the output Vm of maximum current detection circuit 14
2 is higher than the output Vj of the second node, so that the connection point B between the resistors R2 and R3
Becomes negative voltage, the operation of the voltage control circuit is affected by the operation of the current control circuit, and the voltage across the capacitor C1 is increased. The output current value of this converter also increases, and the output of the other converter is increased. As the current approaches the current value, the output current of each converter balances. Note that the resistor R16 is necessary when the output impedance of the current transformer 20 is large, but can operate even when the output impedance is small.

Next, FIG. 7 shows a specific configuration of the current control circuit in the power supply device shown in FIG. In the figure, a primary coil 20A of a current transformer 20 is connected in series between a secondary side of a transformer T1 and a ground GND, and a diode D11 having the illustrated polarity is connected between both ends of one secondary coil 20B of the current transformer 20. Thus, a parallel circuit including a capacitor C11 and a resistor R14 is connected.

Further, the negative electrode side of the capacitor C11 is connected to a control line CL1 via a diode D13, and the anode of the diode D13 is connected to a point B in FIG. 2 via a resistor R12. A circuit including the diodes D11 and D14, the capacitor C11, and the resistor R14 indicated by the broken line is the maximum current detection circuit 14 illustrated in FIGS.

The maximum current detection circuit 14 determines the larger one of the output current value obtained from another converter via the control line CL1 during parallel operation and the output current value obtained from the current transformer 20 as the current detector of the own converter. It operates to output a value as a voltage.

On the other hand, a parallel circuit comprising a capacitor C10 and a resistor R13 is connected between both ends of another secondary coil 20C of the current transformer 20 via a diode D10, and the positive electrode of the capacitor C10 is connected to a diode D12 and a resistor R11. Is connected to point B in FIG.
The circuit including the diodes D10 and D12, the capacitor C10, and the resistor R13 indicated by the broken line is the self-current detection circuit 12 illustrated in FIGS.

The negative side of the capacitor C10 and the positive side of the capacitor C11 (one of the secondary coils 20B and 20C of the current transformer 20) are connected, and this connection point is connected to the ground GND.

In the above configuration, when the current flowing on the secondary side of the transformer T1 changes, a voltage proportional to the current is generated in the secondary coils 20B and 20C of the current transformer 20. This voltage is rectified and smoothed by the self-current detection circuit 12 and the maximum current detection circuit 14, respectively.
4 and the output Vj of the self-current detection circuit 12 to obtain the output Vj of the self-current detection circuit 12 and the maximum current detection circuit 1
The result of adding the negative output −Vm of 4 is added between the ground of the voltage control circuit and the point B.

As described with reference to FIGS. 1 and 3, when the converter is outputting the maximum current, the maximum current detection circuit 14
Is equal to the output Vj of the self-current detection circuit 12, the voltage applied to the connection point B between the resistors R2 and R3 in FIG. 3 is zero, and the operation of the voltage control circuit is not affected by the operation of the current control circuit. No voltage fluctuation.

However, when the other converter is outputting a larger current than its own converter, the maximum current detection circuit 14
Is higher than the output Vj of the self-current detection circuit 12, the voltage applied to the connection point B between the resistors R2 and R3 becomes a negative voltage, and the operation of the voltage control circuit is affected by the operation of the current control circuit. The voltage across C1 is increased, the output current value of the own converter also increases and approaches the output current value of another converter, and the output current of each converter is balanced.

FIG. 8 shows another embodiment of the current control circuit in the power supply device shown in FIG. This embodiment is an example in which the secondary coil of the current transformer 20 is constituted by one. The maximum current detection circuit 14 and the self-current detection circuit 12 are provided between both ends of the secondary coil 20D of the current transformer 20.
Are connected in parallel.

The maximum current detecting circuit 14 is connected between one end of the secondary coil 20D of the current transformer 20 and the ground GND via a diode D11 and a capacitor C11 and a resistor R1.
14 is connected, and a capacitor C11
Is connected to the control line CL1 via the diode D13 from the negative electrode side of.

Further, the anode of the diode D13 is connected to the point B in FIG. 2 via the resistor R12. The circuit composed of the diodes D11 and D14, the capacitor C11, and the resistor R14 shown by the broken line is the maximum current detection circuit 14 shown in FIGS.

The maximum current detecting circuit 14 detects the larger one of the output current value obtained from another converter via the control line CL1 and the output current value obtained from the current transformer 20 as the current detector of the own converter during the parallel operation. It operates to output a value as a voltage.

On the other hand, a diode D is connected between one end of the secondary coil 20D of the current transformer 20 and the ground GND.
A parallel circuit composed of a capacitor C10 and a resistor R13 is connected via a capacitor 10, and is connected from the positive electrode side of the capacitor C10 to a point B in FIG. 3 via a diode D12 and a resistor R11. The diode D1 shown by the broken line
The circuit composed of 0, D12, capacitor C10 and resistor R13 is the self-current detection circuit 12 shown in FIGS.
The negative electrode of the capacitor C10 and the positive electrode of the capacitor C11 are connected to the ground GND.

In the above configuration, when the current on the secondary side of the transformer T1 changes, a voltage proportional to the current is generated in the secondary coil CT-2 of the current transformer CT1. This voltage is supplied to the self-current detection circuit 12 and the maximum current detection circuit 14.
Respectively, the output Vm of the maximum current detection circuit 14 and the output Vj of the self-current detection circuit 12 are obtained by performing rectification and smoothing, and the output Vj of the self-current detection circuit 12 and the negative output −Vm of the maximum current detection circuit 14 are added. The result is added between the ground of the voltage control circuit and point B.

As described with reference to FIG. 3, when the own converter is outputting the maximum current, the output Vm of the maximum current detecting circuit 14 and the output Vj of the self-current detecting circuit 12 are equal, so that the resistances of the resistors R2 and R3 in FIG. The voltage applied to the connection point B is zero, the operation of the voltage control circuit is not affected by the operation of the current control circuit, and there is no voltage fluctuation.

However, when the other converter is outputting a larger current than its own converter, the maximum current detection circuit 14
Is higher than the output Vj of the self-current detection circuit 12, the voltage applied to the connection point B between the resistors R2 and R3 becomes a negative voltage, and the operation of the voltage control circuit is affected by the operation of the current control circuit. The voltage across C1 is increased, the output current value of the own converter also increases and approaches the output current value of another converter, and the output current of each converter is balanced.

Next, FIG. 9 shows the configuration of another embodiment of the current control circuit in the power supply device shown in FIG. In this embodiment, the configuration of the current control circuit shown in FIG. 8 is simplified.

In the figure, a capacitor C12 is connected between both ends of a secondary coil 20D of the current transformer 20 via a diode D14, and a self-current detecting circuit 12 and a maximum current detecting circuit 1 are connected in parallel between both ends of the capacitor C12.
4 are connected in series. That is, the capacitor C10 for the self-current detection circuit 12 and the capacitor C11 for the maximum current detection circuit 14, and the resistors R13 and R14, which are connected in series, are connected in parallel to both ends of the capacitor C12.

The capacitors C10 and C1
1. Each connection point of the resistor R13 and the resistor R14 is connected to the ground GND. Furthermore, self-current detection circuit 1
The positive electrode side of the second capacitor C10 is connected to a connection point B between the resistors R2 and R3 in FIG. 3 via a diode D12 and a resistor R11.

On the other hand, the negative side of the capacitor C11 of the maximum current detection circuit 14 is connected to the connection point B of the resistors R2 and R3 in FIG. 3 via the diode D13 and the resistor R12. The connection point between the diode D13 and the resistor R12 is connected to the control line CL1. The maximum current detection circuit 14 serves as an output current value obtained from another converter via the control line CL1 during parallel operation and as a current detector for its own converter. Of the output current value obtained from the current transformer 20 of this example is output as a voltage. Therefore, as in the circuit of FIG. 8, when the other converter outputs a larger current than the own converter, the output Vm of the maximum current detection circuit 14 is higher than the output Vj of the self-current detection circuit 12,
The voltage applied to the connection point B between the resistors R2 and R3 becomes a negative voltage, and the operation of the voltage control circuit increases the voltage across the capacitor C1 under the influence of the operation of the current control circuit. It rises and approaches the output current value of another converter, and the output current of each converter balances.

FIG. 10 shows a circuit configuration when two converters are connected in parallel using the current control circuit shown in FIG. In the figure, the dashed line indicates each converter 30 and 40. The configuration of the main circuit of each of converters 30 and 40 is the same as that of FIG. 2, and a part thereof is omitted. In the figure, the dotted line indicates wiring for parallel operation, and the load 50 is configured to connect the output terminals 3 and 4 of both converters 30 and 40 to perform parallel operation. In addition, each converter 30, 4
The control lines CL1 of the converters 30 and 40 are connected to each other to perform the output current balance control of 0. The symbols of the components constituting the converters 30 and 40 are the same as those shown in FIGS. 2 and 6 and are given the same symbols.

The maximum current detecting circuits 14 of the converters 30 and 40 are connected in parallel to each other via the control line CL1 and the ground GND, and the capacitor C10 of the other converter and the capacitor C10 of the own converter are connected in parallel. The output of the maximum current detection circuit 14 is equal to the voltage across the capacitor C10 of the converter with the higher voltage. As a result, the voltage between both ends of the capacitor C10 is compared with the voltage between both ends of the capacitor C11 of the own converter. If the voltage between both ends of the capacitor C10 of the own converter is small, the resistor R2 for controlling the voltage of the own converter with respect to the ground GND. As a result, the voltage at the point A, which is the detection point of the output voltage of the voltage control circuit, also drops, so that the voltage control circuit determines that the output voltage of the converter has dropped, and It operates to increase the output voltage of the converter and increases its current sharing to the load 30 of its own converter.

On the other hand, the capacitor C1 of its own converter
When the voltage between both ends of 0 is large, since the voltage between both ends of the capacitor C10 of the converter and the voltage between both ends of the capacitor C11 are equal, the voltage at the point B of the voltage control circuit does not change and does not affect the operation of the current control circuit. .

As described above, since the operation is performed so that the output current of each converter is matched with the converter which outputs the maximum current, the output current of each converter is balanced. Since the converter operates as described above, even if one converter fails and the output becomes zero during the parallel operation of multiple converters, the current control circuit in each converter will switch the converter with the lower output current to the other converter. The converter is configured so as not to have an effect, and a diode D3 is provided on the output side of each converter, so that the reverse current of the current from the load 50 side is prevented, and the converter that has failed like the conventional power supply device can be used. A simple converter can be configured which does not require a device for detecting and using a switch or the like to disconnect it from parallel operation with another converter.

Further, without using expensive and complicated circuits such as operational amplifiers, current transformers, capacitors, resistors,
The current control circuit can be configured with a simple circuit including only a diode, and a small converter with a simple circuit configuration can be obtained. By performing the parallel redundant operation with the number of converters configured as described above capable of supplying a current larger than the load capacity, the power supply device can perform the redundant operation with high reliability.

[0080]

According to the present invention as described above,
A maximum current control method that detects each output current of a plurality of converters and matches the output current of each converter to the maximum output current among them can be realized with simple circuit components and a simple circuit configuration.

Therefore, even if a plurality of converters in parallel operation include a converter whose output current has become zero due to a failure, the failed converter should be detected and disconnected from the parallel operation by a switch or the like. A simple device is not required, and the current supplied to the load can be shared by the remaining converters as they are.

Further, by performing redundant operation in parallel with a number of converters capable of supplying a current larger than the load capacity, the power supply device can perform redundant operation with high reliability.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of an embodiment of a converter used in a power supply device according to the present invention.

FIG. 2 is a circuit diagram showing a specific configuration of the converter shown in FIG.

FIG. 3 is a circuit diagram showing a configuration of another embodiment of the converter used in the power supply device according to the present invention.

FIG. 4 is a circuit diagram showing a specific configuration of one embodiment of the current control circuit shown in FIG. 2;

FIG. 5 is a circuit diagram showing a specific configuration of another embodiment of the current control circuit shown in FIG. 2;

FIG. 6 is a circuit diagram showing a specific configuration of another embodiment of the current control circuit shown in FIG. 2;

FIG. 7 is a circuit diagram showing a specific configuration of one embodiment of the current control circuit shown in FIG. 3;

FIG. 8 is a circuit diagram showing a specific configuration of another embodiment of the current control circuit shown in FIG.

FIG. 9 is a circuit diagram showing a specific configuration of another embodiment of the current control circuit shown in FIG. 3;

FIG. 10 is a circuit diagram showing a specific configuration of an embodiment of the power supply device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 DC voltage terminal 2 DC voltage terminal 3 Output terminal 4 Output terminal 5A Photocoupler 5B Photocoupler 6 3 terminal regulator 7 PWM control circuit 10 Current detector 12 Self-current detection circuit 14 Maximum current detection circuit 16 Addition circuit 20 Current transformer 20A Primary coil 20B Secondary coil 20C Secondary coil 20D Primary coil 30 Converter 40 Converter 50 Load T1 Transformer Q1 Switching element D1 Diode D2 Diode D3 Diode L1 Inductance C1 Capacitor C10 Capacitor C11 Capacitor C12 Capacitor R1 Resistance R2 Resistance R3 Resistance R4 Resistance R11 Resistance resistance

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akira Nana 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd. Hitachi Mizusawa Electronics Co., Ltd. (72) Katsumi Fujikawa, 2880 Kozu, Odawara-shi, Kanagawa Hitachi, Ltd. Storage Systems Division, Hitachi, Ltd. (56) References JP-A-3-195370 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H02J 1/12 H02J 1/10 H02M 3/28

Claims (3)

(57) [Claims] 1. A power supply device for detecting an output voltage and having a voltage control circuit for controlling an output voltage based on the detected output, and a power supply unit for supplying power to a load by performing a parallel redundant operation. A current detector connected in series to the secondary side of a transformer provided on the input side, for detecting the output current of the converter, taking in the detection output of the current detector, and using the detection output as the detection output of the converter itself; And a self-current detection circuit that outputs the detected output of the current detector, compares the detected output with the detected output of the output current of another converter, and detects the output current value of the converter that outputs the maximum current value. A maximum current detection circuit that outputs a value, a sum of an output of the self-current detection circuit and a negative output of the maximum current detection circuit, and outputs the added output to a detection system of the voltage control circuit. Has a current control circuit configured to include a sheet summing means for each converter self current detection circuit, the maximum current detection
A power supply device in which output circuits are connected in series with opposite polarities . 2. An output voltage is detected and based on the detected output.
A converter having a voltage control circuit for controlling the output voltage
Power supply unit that supplies power to loads by operating multiple units in parallel and redundant
Of the transformer provided on the AC input side of each converter
Side connected in series to detect the output current of the converter
A current detector and a detection output of the current detector are taken in, and the detection output is
Self-current detection that outputs voltage as converter output
A circuit and a detection output of the current detector.
Of the converter's output current and the
The output current value of the converter that outputs the current value is used as the detection value.
A maximum current detection circuit to output, an output of the self-current detection circuit, and a negative output of the maximum current detection circuit.
And the added output is detected by the detection system of the voltage control circuit.
Control circuit configured to include an adding means for supplying a current
Has, for each converter self current detection circuit, a power supply device being characterized in that connected in parallel through respective resistors to the maximum current detection circuit in the opposite polarity. Wherein the current detector, power supply device according to claim 1 or 2, characterized in that a current transformer.