JPH11252917A - Parallel connection power unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate reactive power consumed during steady operation by detecting decreasing of an input to a prescribed value or less to allow a shunt current to flow, by providing a current control means comprising a supervisory circuit which supervises the input of a coupling diode and a control circuit which allows the shunt current flow to be on/off. SOLUTION: In a steady-state operating condition, the output voltage generated in a secondary side of a main transformer T11 by switching of a main transistor Q11 in a converter device 1 is full-wave rectified in DA1, DB1, L11, CA1, thereafter smoothed, made to pass through a detector 3 and a supervisory circuit 5 as a DC output, connected in parallel to the other system, and supplied to a load. Then when the output stoppage or lowering down by the generation of an abnormality in the converter device 1 is detected, driving of a TR11 is insufficient or stopped, a base of the next step TR21 is disabled from holding the ground potential, a bias current for protection action by R31, D41 is allowed to flow in the TR21 and it is turned on, so as to allow the shunt current of D11 to flow in R11.

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, and more particularly, to a parallel-coupled power supply device that supplies power to a load by coupling the outputs of a plurality of devices via a diode and that has an improved efficiency.

[0002]

2. Description of the Related Art Conventionally, in a parallel operation power supply device for supplying power to a load by connecting the outputs of a plurality of devices in parallel, the outputs are connected in parallel via a coupling diode.

FIG. 5 shows a conventional two-system parallel redundant operation power supply device. Reference numerals 1 and 2 in FIG. 5 denote DC-DC converters or AC-DC converters, which convert a DC or AC input into a desired DC output, and output the output from a converter of another system via coupling diodes D1 and D2. And supplies power to the load in parallel.

[0004] Reference numerals 3 and 4 denote detectors for generating a feedback control signal to the converter for stabilizing the output voltages of the converters 1 and 2 to a predetermined set value. Also,
The resistances R1 and R2 are used to prevent the output of the other system from flowing to the detector 3 or 4 at D1 or D2 when the output of the own system decreases or stops, so that the stabilizing operation can be performed reliably. This is a shunt resistor that bypasses the reverse leakage current (Ir) of D1 or D2 to the return path.
r) flows.

[0005]

Since the coupling diodes D1 and D2 shown in FIG. 5 are connected to the output of the parallel operation power supply and a load current always flows therethrough, the ineffectiveness consumed by the forward voltage drop (Vf) is lost. An element having a small forward voltage drop (Vf) is selectively used to reduce power.

However, a diode having a small Vf generally has a low reverse withstand voltage (Vr) and a large reverse leakage current (Ir). For this reason, even if a diode having a small Vf is selected and used to reduce the reactive power constantly consumed by the coupling diodes D1 and D2, the output of one system device is reduced or stopped, and a correspondingly large value is used. Due to the Ir, the sneak of the output of the normal other system to the detector 3 or 4 of the abnormal system becomes large, and the stabilizing operation is performed as if the output is normal, thereby causing a malfunction of the device. .

For this reason, the shunt current of the resistors R1 and R2 must be increased, and the reactive power consumed by the resistors R1 and R2 during the steady operation becomes large and cannot be ignored. There was a limit to improving efficiency.

[0008]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems and to provide a means for achieving a further improvement in the efficiency of a parallel-coupled power supply, in which the shunt current flowing through the resistors R1 and R2 is normal. It is unnecessary, and only when the output voltage or output current of any device falls or stops,
Focusing on the points necessary to bypass Ir of D1 and D2, the following means is adopted.

According to a first aspect of the present invention, there is provided current control means including a monitoring circuit for monitoring the input of the coupling diode and a control circuit for turning on and off the shunt current, and detects a drop of the input to a predetermined value or less. Shunt current.

In the above case, when the input returns to a predetermined value or more, the control circuit is turned off to cut off the shunt current and eliminate the reactive power consumed by the shunt current during the steady operation to improve the efficiency. Improve.

On the other hand, when a plurality of devices are connected in parallel via a coupling diode, if the output of any device decreases, the output of another normal device is coupled to the output side of the coupling diode corresponding to the device. Therefore, the input voltage value of the diode becomes smaller than the output voltage value. Therefore,
The difference between the input voltage value and the output voltage value of the coupling diode indicates the normality of the output of the corresponding device.

Therefore, as a second invention, the current control means comprises a monitoring circuit for monitoring a difference between an input voltage value and an output voltage value of the coupling diode, and the control circuit for turning on and off a shunt current. When the value becomes equal to or less than the output voltage value, the control circuit is configured to flow a shunt current as in the case of the first invention.

In the above description, the shunt circuit for the leakage current Ir is the resistor (R1, R2). However, the present invention is not limited to this, and an electronic switch or the like is connected between the two poles of the output of the power supply device. The current is limited so that the current value matches Ir.

Hereinafter, the outline of the present invention will be described with reference to the configuration diagram of the parallel coupled power supply device shown in FIG. 1 and 2 in FIG.
A DC-DC converter or an AC-DC converter similar to the above. D11 and D12 are the above-mentioned coupling diodes, through which the output of the converter is mutually made redundant with the output of the converter of the other system in parallel.

Numerals 3 and 4 denote detectors for producing a feedback control signal to the converter for stabilizing the output voltages of the converters 1 and 2 to a predetermined set value as in FIG. R11 and R12 are shunt resistors that shunt Ir of D11 and D12 to the return path when the contacts S11 and S12 are closed.

Reference numerals 5 and 6 denote monitoring circuits for monitoring the input value of the diode or the difference between the input voltage value and the output voltage value. The monitoring circuit reduces the input value of the diode to a predetermined normal value or less. When the input voltage value of the diode becomes equal to or less than the output voltage value, the contacts S11 and S12 are closed to shunt Ir of D11 and D12. On the other hand, when the input voltage value becomes equal to or more than the output voltage value, the contact S1
1 and S12 are opened to act to cut off the Ir.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 2 and 3 show first and second embodiments of the present invention using a transistor circuit as the control circuit, and FIG. 4 shows an error amplifier using the control circuit. A third embodiment of the present invention will be described. In the following description, two parallel systems are taken as an example and one system is mainly described. Also, the number of parallel circuits of the present invention is not limited to two systems, and it is apparent that the present invention can be applied to the case of multi-system parallel connection.

First, in FIG. 2, reference numeral 1 denotes a DC-DC converter or an AC-DC converter similar to that shown in FIG. 5, but shows only a main circuit portion thereof. A switching transistor, T11 is a main transformer, and DA1, L11, and CA1 are smoothing circuits.

Reference numeral 3 denotes a detector, which forms a feedback control signal to the converter for stabilizing the output voltage of the converter 1 to a predetermined set value, as in FIG. 5, but is constituted by a known circuit. The details are not shown.

Reference numeral 5 denotes a monitoring circuit including the above-described coupling diode.
11 is a shunt resistor. TR21 corresponds to the on / off contact S11 of FIG. 1, and controls the on / off of the current of R11 in response to the input decrease, stop, or recovery of D11.

Next, the operation of the circuit shown in FIG. 2 will be described.
First, in the steady operation state, the output voltage generated on the secondary side of the main transformer T11 by the switching by the main transistor Q11 in the converter 1 is DA1, DB1,
After being subjected to full-wave rectification in L11 and CA1, the signal is smoothed, passed as a DC output through the detector 3 and the monitoring circuit 5, and coupled to another system in parallel, and supplied to the load. Further, the output is used for monitoring as R41.
And supply it to the TR11 base. This monitoring output turns on TR11 and sets the base of the next stage TR21 to the ground potential, so that TR21 is turned off and the shunt current of R11 continues to be cut off.

On the other hand, if an abnormality occurs in the converter 1 and the output stops or drops, the drive of TR11 is insufficient or stopped, and the base of the next stage TR21 cannot hold the ground potential, and R31 and D41 , The bias current for the protection operation wins and TR21 is turned on, and the shunt current of D11 is passed through R11.

This shunt current conduction state is continued until the converter 1 recovers from an abnormality. Then, when the output of the converter returns to normal, TR11 is turned on by the monitor output, and T
The protection operation bias current of R21 is absorbed, TR21 is turned off, and the process ends.

As described above, the first aspect of the present invention has the effect of avoiding the reactive power consumption by the current control means for monitoring the input of the coupling diode and the sneaking of the output to the detector in the event of an abnormality. .

Next, a second embodiment of the present invention will be described with reference to FIG. First, in the normal operation state, the output voltage generated on the secondary side of the main transformer T11 by the switching by the main transistor Q11 in the converter 1 as in FIG. The signal is smoothed, passed through the detector 3 and the monitoring circuit 5 as a DC output, and coupled to another system in parallel to be supplied to a load.

Next, the output is taken out directly from the input side of DA1 for monitoring and smoothed by D31 and C11.
The current is limited at R41 and supplied to the TR11 base. As a result of this monitoring output, TR11 is turned on in the same manner as in the operation of FIG. 2, and the base of the next stage TR21 is set to the ground potential.
21 is turned off, and the state in which the shunt current of R11 is cut off is continued.

Also, when the output of the converter 1 is stopped or the voltage is lowered due to the occurrence of an abnormality in the converter 1, similarly to the case of FIG.
Cannot hold the ground potential, and R31 and D4
1, the bias current for protection operation wins, and the transistor TR21 is turned on, the action of passing the shunt current of D11 to R11 is performed, and the action of automatically flowing the shunt current to avoid the output sneak to the detector. Is fulfilled.

Here, as in the first embodiment,
The diode input monitoring and shunt current control means according to the first aspect of the present invention achieve the effects of avoiding reactive power consumption and avoiding output sneak to the detector.

Next, a third embodiment of the present invention will be described with reference to FIG. In FIG. 4, 1 is the same D as in FIG.
It is a C-DC converter or an AC-DC converter. The detector in FIG. 2 is not shown in FIG. 4 as being included in the converter. Reference numeral 5 denotes a monitoring circuit including the coupling diode described above. D11 in the circuit is a coupling diode, and R11 is a shunt resistor. IA in the circuit
Reference numeral 1 denotes an error amplifier, which corresponds to the contact S11 in FIG.
11 is controlled.

First, in a normal operation state, the input voltage value of the diode D11 becomes higher than the output voltage by Vf due to the voltage drop accompanying the load current. On the other hand, when the output voltage of the converter of the own system decreases or stops, the output of the parallel other system is coupled to the output of the converter of the own system. It becomes lower than the voltage value.

The difference in height and the sign of the Vf are represented by R21 and R3.
1, a bridge composed of R41 and R51 and IA1
Constitutes a comparator and detects and amplifies R11.
1 drives the diode D11 in the range from the input voltage to the ground potential according to the sign of Vf. The Vf is driven by the positive voltage, that is, the input voltage of the diode D11 in the normal operation state, and the Vf is driven by the negative voltage, that is, the ground potential when the output of the converter 1 is stopped or the voltage is lowered.

Thus, during normal operation of the converter, the shunt current of R11 is cut off to avoid reactive power consumption at R11, and when the output of the converter is stopped or the voltage drops, the shunt current of R11 is reduced. Is flowed, and an effect of avoiding the sneak of the output to the detector is performed.

As described above, the shunt current control action by monitoring the difference between the input voltage value and the output voltage value of the coupling diode according to the second invention is performed, and the shunt current is controlled similarly to the first invention. To prevent the reactive power consumption and the output sneak to the detector at the time of abnormality.

[0034]

As described above, according to the present invention, the reactive power consumed by the reverse leakage current of the parallel-coupling diode is reduced, and the efficiency of the parallel-coupling power supply device is improved. . Further, there is an effect that the sneak of the output to the detector is reduced and the stability of the device is improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a parallel coupled power supply device of the present invention.

FIG. 2 is a circuit according to a first embodiment of the present invention.

FIG. 3 is a circuit according to a second embodiment of the present invention.

FIG. 4 is a circuit according to a third embodiment of the present invention.

FIG. 5 is a conventional two-system parallel redundant operation power supply device.

[Explanation of symbols]

 1,2 converter 3,4 detector 5,6 monitoring circuit

Claims (3)

[Claims] A plurality of power supplies each having an output coupled in parallel via a diode to supply power to a load; monitoring an input of the diode to determine a reverse leakage current of the diode based on the detected value; A parallel-coupled power supply device comprising: a current control means for absorbing. 2. The device according to claim 1, wherein said current control means further detects a voltage on the output side of the diode and absorbs the leakage current based on a difference between the two detected values. Parallel coupled power supply. 3. The parallel-coupled power supply device according to claim 1, wherein said current control means is configured to absorb a leakage current by connecting a shunt circuit between output terminals of said power supply device.