JP2000322132A - Parallel power unit operating circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a parallel power unit operating circuit which makes respective power units to take partial charge of output currents even in case of environmental variation such as temperature variation and characteristic variation of a circuit element by comparing respective output voltages with a minimum voltage and controlling the adjustment quantities of the respective output currents according to the comparison results. SOLUTION: The output voltages V1 and V2 of the power units 2 and 3 are detected and a minimum voltage (V+) between the detected output voltage V1 and V2 is decided; and the detected output voltages V1 and V2 are compared with the minimum voltage (V+) and the adjustment quantities of output currents I1 and I2 by output current adjusting elements Q1 and Q2 connected to the output lines of the power units 2 and 3 are controlled according to the comparison result. Consequently, the partial charge of the output currents I1 and I2 of the power units 2 and 3 is equalized. Therefore, even if the output voltages V1 and V2 of the power units 2 and 3 become different or a circuit element varies in characteristics, the partial charge of the output currents I1 and I2 of the power units 2 and 3 can be equalized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parallel power supply operation circuit for equalizing the current sharing of each power supply when a plurality of power supplies are operated in parallel and redundant operation.

[0002]

2. Description of the Related Art An example of a conventional parallel power supply operation circuit 20 will be described with reference to FIG.

In the parallel power supply operation circuit 20 shown in FIG. 2, for example, when 100 W of power is required to be supplied to the load Z, two power supplies (100 W rated) connected to the AC power supply 11 respectively. DC power supply devices 12 and 13 are prepared, one power supply device 12 and the load Z are connected via an ORing diode D11 and a resistor R21, and the other power supply device 13 and the load Z are connected for an ORing. Diode D
12. Connect via resistor R22.

[0004] Therefore, even if one of the two power supply devices 12 and 13 fails, for example, 100 W of power supply from the other power supply device 13 to the load Z can be continued without any trouble.

[0005]

In the parallel power supply operation circuit shown in FIG. 2, the output voltages of the power supply units 12 and 13 are made as equal as possible, and the output currents of the power supply units 12 and 13 are equalized. To achieve this, the resistor R2
1. It is necessary to make the resistance value of R22 as equal as possible.

That is, what determines the ratio of the current sharing between the power supply devices 12 and 13 is the output voltage of each of the power supply devices 12 and 13 and the resistance value of each of the resistors R21 and R22.

For this reason, at the time of shipment, each of the power supply units 12, 13
The setting of the output voltage must be strictly performed, and
The resistors R21 and R22 need to be designed to have the same rating as much as possible.

However, in practice, each power supply device is changed due to a change with time of the load Z, a difference in output voltage due to a temperature difference between the power supply devices 12 and 13, and a difference in impedance due to a temperature difference between the ORing diodes D11 and D12. 12,
There is a problem that the current sharing of the T.13 becomes uneven.

In view of the above, according to the present invention, when a plurality of power supply units are operated in parallel and redundantly, even when environmental conditions such as a temperature change or a characteristic change of a circuit element occur, the sharing of the output current of each power supply unit is always equalized. And a parallel power supply operating circuit.

[0010]

According to the first aspect of the present invention,
In a parallel power supply operation circuit that operates by connecting output lines of a plurality of power supply units in parallel, a plurality of voltage detection circuits detecting each output voltage of the plurality of power supply units, and each output voltage detected by the plurality of voltage detection circuits A minimum voltage determination circuit that determines a minimum voltage of the plurality of power supply devices, a plurality of output current adjustment elements each connected to an output line of the plurality of power supply devices, and capable of adjusting the output current of each power supply device to a large or small value; Each output voltage detected by the detection circuit is compared with the minimum voltage determined by the minimum voltage determination circuit, and the amount of adjustment of each output current by each output current adjustment element is controlled according to the comparison result.
And a plurality of output current control circuits for equalizing the current sharing of the respective output currents of the plurality of power supply devices.

According to the present invention, each output voltage of the plurality of power supply devices is detected, the minimum voltage among the detected output voltages is determined, and each detected output voltage is compared with the minimum voltage to obtain a comparison result. By controlling the amount of adjustment of each output current by each output current adjusting element connected to the output lines of the plurality of power supply devices, the current sharing of each output current of the plurality of power supply devices is equalized. .

Therefore, even if the output voltages of a plurality of power supply units differ due to environmental conditions such as temperature changes, or if the characteristics of the circuit elements constituting the parallel power supply operation circuit change due to changes over time, etc. The sharing of the output current of each power supply device can always be equalized.

According to a second aspect of the present invention, in a parallel power supply operating circuit which operates by connecting output lines of two power supplies in parallel, each output voltage of the two power supplies is detected.
A plurality of voltage detection circuits, a minimum voltage determination circuit for determining a minimum voltage among the output voltages detected by the two voltage detection circuits, and output voltage lines of the two power supply devices, respectively.
A comparison is made between two output current adjusting elements capable of adjusting the output current of each power supply device to large and small, each output voltage detected by the two voltage detection circuits, and a minimum voltage determined by a minimum voltage determination circuit. And two output current control circuits for controlling the amount of adjustment of each output current by each of the output current adjustment elements according to the comparison result and equalizing the current sharing of each output current of the two power supply devices. It is characterized by the following.

According to the present invention, each output voltage of the two power supply devices is detected, the minimum voltage among the detected output voltages is determined, and each detected output voltage is compared with the minimum voltage. By controlling the amount of adjustment of each output current by each output current adjusting element connected to the output line of the two power supplies according to the comparison result, the current sharing of each output current of the two power supplies is equalized. It becomes something.

Therefore, even if the output voltages of the two power supply units differ due to environmental conditions such as temperature change, or if the characteristics of the circuit elements constituting the parallel power supply operation circuit change due to aging or the like. In addition, it is possible to always equalize the sharing of the output current of each power supply device.

According to a third aspect of the present invention, there is provided a parallel power supply operation circuit which operates by connecting output lines of two power supply units in parallel, wherein a resistor and an operational amplifier for detecting each output voltage of the two power supply units are provided. Two voltage detection circuits used,
A minimum voltage determination circuit using a diode for determining a minimum voltage among the output voltages detected by the two voltage detection circuits; and a minimum voltage determination circuit connected to the output lines of the two power supply units, and an output current of each power supply unit. Two large and small adjustable FETs
And each output voltage detected by the two voltage detection circuits is compared with a minimum voltage determined by a minimum voltage determination circuit, and a saturation amount of each of the FETs is controlled in accordance with the comparison result. And two output current control circuits each using an operational amplifier for equalizing the output current.

According to the present invention, each output voltage of the two power supply devices is detected by two voltage detection circuits each using a resistor and an operational amplifier, and each output voltage detected by a minimum voltage determination circuit using a diode. And the output current control circuit using two operational amplifiers compares each output voltage detected by the two voltage detection circuits with the minimum voltage determined by the minimum voltage determination circuit. Then, the saturation current of each FET connected to the output line of each of the two power supply devices is controlled in accordance with the comparison result to equalize the output current of each power supply device.

Therefore, the output voltage of the two power supplies differs due to environmental conditions such as temperature change, and the characteristics of circuit elements such as operational amplifiers and diodes constituting the parallel power supply operation circuit change due to aging or the like. Even when the power supply device is generated, the sharing of the output current of each power supply device can always be equalized.

[0019]

Embodiments of the present invention will be described below in detail.

FIG. 1 shows a parallel power supply operation circuit 10 according to the present embodiment.
Numeral 0 supplies power to the load Z by connecting the output lines of the power supplies 2 and 3 which are two DC power supplies connected to the AC power supply 1 in parallel.

The parallel power supply operation circuit 10 includes two voltage detection circuits for detecting the output voltages of the two power supplies 2 and 3, and a minimum voltage (V +) of the detected detection voltages V1 and V2. ), And a drain and a source are connected to the output lines of the two power supplies 2 and 3, respectively, and the output currents I1 and I2 of the power supplies 2 and 3 are determined. FET Q that is an output current adjusting element and an ORing element that can adjust
1 and Q2, a minimum voltage determination circuit using diodes D1 and D2 for determining the minimum voltage (V +) of the detection voltages V1 and V2 detected by the two voltage detection circuits, and the two voltage detection circuits Each detection voltage V1, V detected by the circuit
2 are taken from the inverting input terminals and compared with the minimum voltage (V +) determined by the minimum voltage determination circuit. According to the comparison result, the gates of the FETs Q1 and Q2 are controlled via resistors R2 and R4. Send a signal to each FET Q1, Q
2 to control the output current IO of each of the power supply units 2 and 3
Using operational amplifiers IC2 and IC4, respectively.
Output current control circuits.

One of the voltage detection circuits is a voltage detection resistor R1 connected in series to the output line of the power supply device 2, and a voltage amplification operational amplifier having an inverting input terminal and a non-inverting input terminal connected to both ends of the resistor R1. IC1.

The other voltage detecting circuit comprises a voltage detecting resistor R3 connected in series to the output line of the power supply 3, and a voltage amplifying operational amplifier having an inverting input terminal and a non-inverting input terminal connected to both ends of the resistor R3. IC3.

The output terminals of the operational amplifiers IC1 and IC3 of the two voltage detection circuits are connected to the power supply units 2 and 3 respectively.
The detection voltages V1 and V2 are output in proportion to the output voltage.

The minimum voltage judging circuit has a cathode connected to an output terminal of the operational amplifier IC1 and an operational amplifier IC2.
Diode D1 whose anode is connected to the non-inverting input terminal of
A diode D3 having a cathode connected to the output terminal of the operational amplifier IC3 and an anode connected to the non-inverting input terminal of the operational amplifier IC4.
1, both anodes of the diode D3 are connected, and a predetermined drive voltage Vcc is applied through the resistor R5 to the diode D1,
The supply is made to each anode of the diode D3.

An ORing diode D2, D4 is connected in parallel to each of the FETs Q1, Q2.

Next, the operation of the parallel power supply operation circuit 10 of the present embodiment having the above-described configuration will be described.

Now, the output current I of each of the power supply units 2 and 3 will be described.
Assuming that the relationship between I1 and I2 is in the state of I1 <I2, each detection voltage V1 detected by the two voltage detection circuits
, V2 also satisfies V1 <V2. In this case, the minimum voltage (V +) determined by the minimum voltage determination circuit using the diodes D1 and D2 is the sum of the detection voltage V1 and the drop voltage Vd of the diode D1.

The two output current control circuits take in the respective detection voltages V1 and V2 detected by the two voltage detection circuits from respective inverting input terminals, and receive the minimum voltage (V +) determined by the minimum voltage determination circuit. And the resistors R3 and R4 are connected to the gates of the FETs Q1 and Q2 according to the comparison result.
Control signals VG1 and VG2 are transmitted through the FETs Q1 and VG2.
, Q2 are controlled.

That is, the gain (K) of the operational amplifier IC2
If 2) is sufficiently large, the control signal VG1 from the operational amplifier IC2 becomes Vcc. As a result, the power supply device 2 side F
ETQ1 becomes saturated, and the occurrence of loss in FET Q1 is minimized.

On the other hand, since the relationship between the detection voltages V1 and V2 is V1 <V2, the control signal (control voltage) VG2 from the operational amplifier IC4 is reduced, the gate voltage of the FET Q2 is reduced, and the circuit operates in an unsaturated state. As a result, the drain-source voltage becomes higher than the drain-source voltage of the FET Q1. As a result, the output current I2 on the side of the power supply 3 decreases, the output current I1 on the side of the power supply 2 increases, and both output currents I1 and I2 change from the state of I1 <I2 to the state of I1 = I2. And so on.

In the above operation, the FET
The loss generated in Q1 and Q2 increases as the difference between the output voltages V1 and V2 between the power supply devices 2 and 3 increases. However, the output voltages V1 and V2 of the power supply devices 2 and 3 are completely the same. If there is no difference in element performance, FET Q2 and FET Q1
As in the case of the above, the state becomes saturated and the occurrence of loss is minimized.

In this way, when the power supply units 2 and 3 having no redundant operation function are operated in parallel, the current sharing of each power supply unit can be equalized by an external circuit, and a minimum loss is generated. Equalization of current sharing can be realized.

Next, an operation analysis of the parallel power supply operation circuit 10 according to the present embodiment having the above-described configuration will be described.

Assuming that the gains of the operational amplifiers IC1 and IC3 are (K1) and the resistance values of the resistors R1 and R2 are Rs, the detection voltage V1 is V1 = K1RsI1, and the detection voltage V2 is V2 = K1RsI2. Can be represented.

Here, if I1 <I2, V1 <V2
And the drop voltage of the diodes D1 and D2 is V
d, the minimum voltage (V +) is (V +) = V1 + V
It can be represented by d.

Assuming that the gains of the operational amplifiers IC2 and IC4 are (K2), the control signal V from the operational amplifier IC2 is
G1 can be represented by VG1 = K2 Vd, and the operational amplifier I
The control signal from C4) VG2 is given by VG2 = K2 ＋ V + (− V
d) It can be expressed as follows:｝ = K2 K1 (I1 -I2) + K2 Vd.

Here, the gain (K2) is sufficiently large (K2
2 >> 1), the control signal VG1 satisfies VG1 = Vcc, and the FET Q1 operates in a saturated state.

The load Z has two output currents I 1,
It is assumed that an output current I0 (= I1 + I2) which is the sum of I2 is supplied.

On the other hand, it is assumed that the FET Q2 is operating in an unsaturated state, and VGO is changed to the output voltage VO and the FET Q2.
Assuming that g2 is the reciprocal of the forward voltage admittance of the FET Q2, g2 I2 = VG2-VGO
Is established.

The relational expression between VG1 and VG2 described above, I0 = I1
By rearranging the relational expression of + I2 and the relational expression of g2 I2 and solving for I2, the following equation 1 is established.

[0042]

(Equation 1) In Equation 1, the gain (K2) is sufficiently large (K2 >>).
1) Therefore, I2 = (1/2) I is satisfied, and it is found that the two output currents I1 and I2 are equalized from the state of I1 <I2 to the state of I1 = I2. I do.

In this embodiment, the power supply devices 2, 3
However, the present invention is not limited to this, and can be implemented with an arbitrary number of power supply devices.

[0044]

According to the present invention, the output voltage of a plurality of or two power supply units may differ due to environmental conditions such as temperature change, and these parallel power supply unit operation circuits may be configured due to a change over time or the like. Even if the characteristic change of the circuit element occurs, it is possible to provide a parallel power supply operation circuit capable of equalizing the sharing of the output current of each of a plurality of or two power supply units.

Further, according to the present invention, the output voltage of the two power supply units may differ due to environmental conditions such as temperature change, or the operational amplifiers, diodes, etc. constituting this parallel power supply operation circuit due to changes over time or the like. It is possible to provide a parallel power supply operation circuit capable of equalizing the output currents of the two power supplies at all times even when the characteristic change of the circuit element occurs.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a parallel power supply device operation circuit according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a conventional parallel power supply device operation circuit.

[Explanation of symbols]

 1 AC power supply 2 Power supply 3 Power supply 10 Parallel power supply operation circuit D1 Diode D2 Diode D3 Diode Q1 FET Q2 FET I0 Output current VO Output voltage IC1 Operational amplifier IC2 Operational amplifier IC3 Operational amplifier IC4 Operational amplifier Z Load

Claims (3)

[Claims] 1. A parallel power supply operation circuit that operates by connecting output lines of a plurality of power supply devices in parallel, comprising: a plurality of voltage detection circuits for detecting output voltages of the plurality of power supply devices; and a plurality of voltage detection circuits. A minimum voltage determination circuit that determines a minimum voltage among the output voltages to be detected; a plurality of output current adjusting elements that are respectively connected to output lines of the plurality of power supply devices and are capable of adjusting the output current of each power supply device to large and small. Each output voltage detected by the plurality of voltage detection circuits,
A minimum voltage determined by a minimum voltage determination circuit is compared, and the amount of adjustment of each output current by each output current adjustment element is controlled in accordance with the comparison result, so that the current sharing of each output current of the plurality of power supply devices is equalized. And a plurality of output current control circuits. 2. A parallel power supply operation circuit which operates by connecting output lines of two power supply units in parallel, comprising: two voltage detection circuits for detecting respective output voltages of the two power supply units; A minimum voltage judging circuit for judging a minimum voltage among the respective output voltages detected by the voltage detecting circuit; and two pieces each of which is connected to output lines of two power supply units and which can adjust the output current of each power supply unit to a large or small value. An output current adjusting element, and each output voltage detected by the two voltage detection circuits;
The minimum voltage determination circuit compares the minimum voltage determined by the minimum voltage determination circuit, controls the amount of adjustment of each output current by each of the output current adjustment elements according to the comparison result, and shares the output current of each of the two power supply devices. A parallel power supply operating circuit, comprising: two output current control circuits for equalizing. 3. A parallel power supply operation circuit which operates by connecting output lines of two power supply units in parallel, wherein two voltages each using a resistor and an operational amplifier for detecting each output voltage of the two power supply units. A detection circuit; a minimum voltage determination circuit using a diode for determining a minimum voltage among the output voltages detected by the two voltage detection circuits; and a power supply device connected to the output lines of the two power supply devices, respectively. Two FETs whose output currents can be adjusted to be large and small, and output voltages detected by the two voltage detection circuits;
Each of the operational amplifiers compares the minimum voltage determined by the minimum voltage determination circuit and controls the saturation amount of each FET according to the comparison result to equalize the output current of each power supply device.
A parallel power supply operating circuit comprising: a plurality of output current control circuits;