JP3652285B2 - Parallel power supply system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a parallel power supply system in which the outputs of a plurality of power supply circuits whose inputs and outputs are insulated by a transformer are used in parallel, and in particular, any power supply by operating a plurality of power supply circuits in parallel. The present invention relates to a power supply output operation that can be continued even if a circuit breaks down.
[0002]
[Prior art]
For example, a parallel power supply system in which operation power is supplied from a plurality of power supply circuits is desirable in an electronic application system, apparatus, or device in which reliability for operation continuity is important, such as a server system. This parallel power supply system also has an advantage that it can easily cope with various power specifications by simply adding an arbitrary number of pre-standardized power supply circuits.
[0003]
FIG. 3 shows a configuration example of a conventional parallel power supply system. The power supply system shown in the figure is composed of two independent power supply circuits 1A and 1B. The power supply circuits 1A and 1B are insulated from each other by a signal input transformer T3 and a power output transformer PT. In this insulation, the two power MOS transistors Q1 and Q2 perform switching control of the input current from the input power supply 2 and energize the primary coil of the power output transformer PT. The primary coil of the power output transformer PT has a center tap, and the transistors Q1 and Q2 form a kind of push-pull output circuit by switching the energization of the primary coil according to the current direction.
[0004]
The transistors Q1 and Q2 are alternately turned on with a predetermined time difference (or phase difference) by the control signals φ1 and φ2 input through the signal input transformer T3. The signal input transformer T1 is a transformer in which the primary coil and the secondary coil are insulated. In order to drive the transistors Q1 and Q2 with a predetermined time difference, that is, the transistors are turned on / off independently of each other in terms of timing. Therefore, one transistor is provided for each of the transistors Q1 and Q2.
[0005]
Each signal input transformer T3 inputs control signals φ1 and φ2 input from the control circuit 3 via the buffer driver 31 to the control terminals (between the gate and the source) of the transistors Q1 and Q2. Although not shown in the figure, the control circuit 3 has timings for causing the transistors Q1 and Q2 to perform a push-pull operation, and controls signals φ1 and φ2 that feedback control the output voltage of the parallel power supply system to a predetermined target value. Is generated.
[0006]
The outputs of the power supply circuits 1A and 1B are respectively taken from the secondary side of the power output transformer PT. The alternating current (high frequency) output extracted from the secondary side is rectified by the diodes D1 and D2, and then passed through a choke coil Lh that forms a ripple filter. The output passed through the choke coil Lh is combined into one power supply output by the common smoothing capacitor C1.
[0007]
FIG. 4 shows another configuration example of a conventional parallel power supply system. In the parallel power supply system shown in the figure, the power MOS transistors Q1 and Q2 in each of the power supply circuits 1A and 1B form a forward type (modified single circuit) drive circuit. With this method, a power output transformer PT that does not have a center tap in the primary coil can be used. However, also in this case, the input / output of each power supply circuit 1A, 1B is insulated by the signal input transformer T4 and the power output transformer PT, respectively. The outputs of the two power supply circuits 1A and 1B are combined and output in parallel as shown in FIG.
[0008]
In the above-described parallel power supply system (FIG. 3 or FIG. 4), two power supply circuits 1A and 1B are operated in parallel in a state where they are insulated from each other by transformers T3, PT or T4, PT. ), The power output operation can be continued. Therefore, if this parallel power supply system is used, the reliability with respect to the continuation of operation of an electronic application system such as a server system, an apparatus, or a device can be greatly enhanced. Moreover, it is possible to easily cope with various power specifications by adding an arbitrary number of standardized power supply circuits.
Note that the power supply circuit shown in FIGS. 3 and 4 is a technique proposed and studied by the inventor prior to making the present invention.
[0009]
[Problems to be solved by the invention]
The parallel power supply system as described above has an advantage that the reliability of the power supply output operation can be improved by operating a plurality of power supply circuits in parallel, and can easily cope with various power specifications depending on the number of power supply circuits. On the other hand, since multiple power supply circuits with the same configuration are used, the circuit scale, such as the number of parts and mounting space, has increased, and in particular, the number of transformers that occupy a large proportion of space and weight has increased, making it smaller and lighter. There was a problem that was disturbed. However, the transformer that is the main cause of the problem is indispensable for operating the power supply circuits independently of each other and ensuring insulation between the input and output of each power supply circuit.
[0010]
Incidentally, in the parallel power supply system shown in FIG. 3, since it is necessary to control the two transistors Q1 and Q2 in each of the power supply circuits 1A and 1B independently of each other in terms of timing, a signal input transformer T3 is provided for each transistor Q1 and Q2. Must be placed. For this reason, a total of four independent signal input transformers T3 are required, two for each of the power supply circuits 1A and 1B. Each of the power supply circuits 1A and 1B operating independently of each other has a control circuit 3. Therefore, a total of two control circuits 3 are necessary. Also for the buffer driver 31, in order to input the control signals φ1 and φ2 from each control circuit 3 to the four signal input transformers T3, respectively, the number of the signal input transformers T3 is necessary, that is, a total of four. It was.
[0011]
The present invention has been made in view of the background as described above. The purpose of the present invention is to make a plurality of power supply circuits constituting a parallel power supply system independent of each other, and even if any power supply circuit fails, The power supply output operation can be continued, and the number of parts required for the configuration of the parallel power supply system can be reduced, and the number of transformers that occupy a large proportion of space and weight can be reduced, enabling a significant reduction in size and weight. There is.
[0012]
[Means for Solving the Problems]
The means according to the present invention uses the outputs of a plurality of power supply circuits that are isolated from each other by a transformer and operated independently from each other, and uses the power supply even if any power supply circuit fails. A parallel power supply system in which the output operation is continued, and the parallel power supply system includes the following configurations (11) to ( 14 ).
(11) Each power supply circuit controls switching of the input current energized to the primary side of the power output transformer by a plurality of current control elements, and the output of each power supply circuit is taken out from the secondary side of the power output transformer, respectively. It is synthesized in parallel.
(12) Each of the plurality of current control elements in each power supply circuit is controlled in operation by a control signal transmitted through a signal input transformer in which the primary coil and the secondary coil are insulated.
(13) The signal input transformer has a plurality of secondary coils with respect to one primary coil, and a control signal transmitted to each secondary coil is distributed to the current control elements in a plurality of power supply circuits. Input.
( 14 ) The primary side of the output transformer and the secondary coil of the signal input transformer are insulated from each other between the power supply circuits.
[0013]
According to the above means, the plurality of power supply circuits constituting the parallel power supply system are operated independently from each other, and the number of parts necessary for the configuration of the parallel power supply system is ensured while ensuring the insulation between the input and output in each power supply circuit. In particular, the required number of transformers, which occupy a large proportion in terms of space and weight, can be reduced, thereby achieving a significant reduction in size and weight of the parallel power supply system.
[0014]
In the above means, each power supply circuit switches the input current energized to the primary side of the power output transformer by using a plurality of current control elements whose operations are controlled at independent timings having a time difference from each other by a plurality of control signals. When configured to control, the necessary number of transformers can be reduced by specifying the following means in addition to the above means.
[0015]
That is, the signal input transformer is provided with a plurality of control signals having different on / off control timings, and each has a plurality of secondary coils corresponding to the number of the power supply circuits. At the same time, the current control elements in each power supply circuit are controlled in operation at independent timings having a time difference from each other by a control signal branched to the secondary coil of the signal input transformer.
[0016]
In the above means, each power supply circuit can be constituted by using two current control elements. The two current control elements can form, for example, a push-pull type output circuit or a forward type output circuit.
[0017]
The output of each power supply circuit can be combined into one power supply output by taking out from the secondary side of the power output transformer, rectifying, passing through a ripple filter, and then connecting to a common smoothing capacitor.
[0018]
As the current control element in each power supply circuit, a semiconductor active element capable of on / off switching operation is used. As this semiconductor active element, for example, a MOS transistor driven by a voltage signal and performing current control Alternatively, a bipolar transistor that is driven by a current signal and performs current control can be used. Alternatively, an insulated gate bipolar transistor (IGBT) having both characteristics of a high input impedance of MOS and a high current driving capability of bipolar may be used.
[0019]
As a means for rectifying the output of each power supply circuit, for example, a diode element having a rectifying characteristic such as a pn junction diode or a Schottky diode can be used easily, but a synchronous rectifier circuit using a switching element such as a transistor is used. For example, voltage loss during rectification, for example, voltage loss due to the forward voltage of the diode can be reduced. As a transistor used in this synchronous rectifier circuit, a MOS transistor having a low saturation voltage is suitable.
[0020]
Each power supply circuit can employ a so-called switching control system in which the input current is switching-controlled at a high frequency.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an embodiment of a parallel power supply system according to the present invention. The parallel power supply system shown in the figure is constituted by two independent power supply circuits 1A and 1B. The power supply circuits 1A and 1B are insulated from each other by signal input transformers T1a and T1b and a power output transformer PT. In the insulated state, the two power MOS transistors Q1 and Q2 switch the input current from the input power supply 2 and energize the primary coil of the power output transformer PT. The primary coil of the power output transformer PT has a center tap, and the transistors Q1 and Q2 form a kind of push-pull output circuit that controls switching of energization of the primary coil according to the current direction.
[0022]
Each of the signal input transformers T1a and T1b is obtained by winding one primary coil L1 and two secondary coils L21 and L22 around the same core (magnetic core), and the coils L1, L21, and L22 are insulated from each other. ing. One control circuit 3 is provided for the two signal input transformers T1a and T1b. The control circuit 3 generates a pair of control signals φ1 and φ2 having a predetermined time difference (phase difference or time offset) from each other in order to operate the transistors Q1 and Q2 in a push-pull manner so as not to be turned on simultaneously. One (φ1) of the pair of control signals φ1 and φ2 is input to the primary coil L1 of the first signal input transformer T1a via the buffer driver 31, and the other (φ2) is input to the first coil L1 via the buffer driver 31. 2 is input to the primary coil L1 of the signal input transformer T1b.
[0023]
One control signal φ1 input to the primary coil L1 of the first signal input transformer T1a is branched and transmitted to the two secondary coils L21 and L22 in the transformer T1a. Control signal φ1 transmitted to one secondary coil L21 is input in phase to the control terminal (between gate and source) of one transistor Q1 in first power supply circuit 1A. The control signal φ1 transmitted to the other secondary coil L22 is input in phase to the control terminal of one transistor Q1 in the second power supply circuit 1B.
[0024]
The other control signal φ2 input to the primary coil L1 of the second signal input transformer T1b is branched and transmitted to the two secondary coils L21 and L22 in the transformer T1b. The control signal φ2 transmitted to one secondary coil L21 is input in reverse phase to the control terminal (between gate and source) of the other transistor Q2 in the first power supply circuit 1A. Further, the control signal φ2 transmitted to the other secondary coil L22 is input in reverse phase to the control terminal of the other transistor Q2 in the second power supply circuit 1B.
[0025]
Thereby, only one transistor Q1 in each of the two power supply circuits 1A and 1B is turned on at the timing when one control signal φ1 becomes active, and two power supply circuits at the timing when the other control signal φ2 becomes active. Only the other transistor Q2 in 1A and 1B is turned on. That is, the transistors Q1 and Q2 in the first power supply circuit 1A and the transistors Q1 and Q2 in the second power supply circuit 1B are two signal input transformers T1a provided in common to both power supply circuits 1A and 1B. , T1b, the control signals φ1 and φ2 are turned on alternately with a predetermined time difference.
[0026]
The outputs of the power supply circuits 1A and 1B are respectively taken from the secondary side of the power output transformer PT. The alternating current (high frequency) output extracted from the secondary side is rectified by the diodes D1 and D2, and then passed through a choke coil Lh that forms a ripple filter. The output passed through the choke coil Lh is combined into one power supply output by the common smoothing capacitor C1.
[0027]
In the foregoing embodiment, two power supply circuits 1A constituting the parallel power system, causes independently operate together 1B, the power supply circuits 1A, while ensuring the insulation between input and output in 1B, the number of signal input transformer Can be halved from 4 to 2. In this case, each of the signal input transformers T1a and T1b is wound with two sets of secondary coils L21 and L22. The secondary coils L21 and L22 are wound around the same core. The increase in transformer space and weight is negligible. At least as compared with the case of adding an independent transformer, the mounting space and weight of the parallel power supply system are greatly reduced.
[0028]
In addition, with the common use of the signal input transformer, the control circuit 3 that generates the control signals φ1 and φ2 can be shared by one in the entire system. Further, the buffer driver 31 for inputting the control signals φ1 and φ2 to the primary side of the signal input transformers T1a and T1b can be shared by two in the entire system. In this way, the number of parts required for the configuration of the parallel power supply system, particularly the necessary number of transformers that occupy a large proportion of space and weight, can be reduced, and a significant reduction in size and weight can be achieved.
Further, the primary side of the output transformer PT and the secondary coils L21 and L22 of the signal input transformers T1a and T1b are insulated from each other between the power supply circuits 1A and 1B, respectively, so that any one of the power supply circuits 1A or 1B fails. Even so, a parallel power supply system is configured in which the power supply output operation can be continued by another power supply circuit 1B or 1A.
[0029]
FIG. 2 shows another embodiment of the parallel power supply system of the present invention. The description will be focused on the main difference from the above-described embodiment. In the parallel power supply system shown in the figure, the power MOS transistors Q1 and Q2 form an output circuit of a forward system (modified single circuit). With this method, a power output transformer PT that does not have a center tap in the primary coil can be used.
[0030]
In this embodiment, only one signal input transformer T2 is provided for the two power supply circuits 1A and 1B. This signal input transformer T2 has four secondary coils L21 to L24 for one primary coil. The control signals transmitted to the secondary coils L21 to L24 are distributed and input to the transistors Q1 and Q2 in the two power supply circuits 1A and 1B. Thereby, the transistors Q1 and Q2 in the two power supply circuits 1A and 1B can be forward-operated with one signal input transformer T2. That is, the conventional system shown in FIG. 4 requires two signal input transformers T4, but in this embodiment, it is reduced to one signal input transformer T2. As a result, as in the case of the above-described embodiment, the two power supply circuits 1A and 1B constituting the parallel power supply system are operated independently of each other, and insulation between the input and output in each power supply circuit 1A and 1B is secured. The required number of transformers that occupy a large proportion of space and weight can be reduced, and the system can be reduced in size and weight.
[0031]
As mentioned above, although this invention was demonstrated based on the typical Example, this invention can have various aspects other than having mentioned above. For example, the current control element that performs switching control of the input power supply 2 may be an active element other than a MOS transistor, such as a bipolar transistor or an IGBT. Further, the diodes D1 and D2 that rectify the alternating current (high frequency) output appearing on the secondary side of the power output transformer PT may be replaced with a synchronous rectifier circuit that controls the direction of current flow with a switching element such as a transistor. If this synchronous rectifier circuit is constituted by a MOS transistor having a low saturation voltage, voltage loss in the rectifier circuit can be reduced.
[0032]
Furthermore, the parallel power supply system of the above-described embodiment has a configuration in which the outputs of the two power supply circuits 1A and 1B are combined in parallel. However, the present invention uses the outputs of three or more power supply circuits in parallel. It can also be applied to parallel power supply systems. For example, when three or more push-pull power supply circuits shown in FIG. 1 are used in parallel, three or more secondary coils corresponding to the number of power supply circuits used are wound around the signal input transformer, and each secondary The control signal branched to the coil may be distributed and input as a control signal to the current control element in each power supply circuit.
[0033]
【The invention's effect】
According to the present invention, a plurality of power supply circuits constituting a parallel power supply system can be made independent from each other, and even if any power supply circuit fails, the power supply output operation can be continued by another power supply circuit. This makes it possible to reduce the number of components required for the configuration, particularly the number of transformers that occupy a large proportion of space and weight, thereby achieving a significant reduction in size and weight of the parallel power supply system.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing an embodiment of a parallel power supply system according to the present invention.
FIG. 2 is a circuit diagram showing another embodiment of the parallel power supply system according to the present invention.
FIG. 3 is a circuit diagram showing a configuration example of a conventional parallel power supply system.
FIG. 4 is a circuit diagram showing another configuration example of a conventional parallel power supply system.
[Explanation of symbols]
1A, 1B Power supply circuit 2 Input power supply 3 Control circuit 31 Buffer driver T3, T4 Signal input transformer (conventional)
T1a, T1b, T2 signal input transformer (present invention)
L1 Primary coil L21 to L24 Secondary coil Q1, Q2 MOS transistor (current control element)
PT Power output transformer D1, D2 Diode Lh Choke coil C1 Smoothing capacitor φ1, φ2 Control signal

Claims (13)

By using the outputs of multiple power supply circuits that are isolated from each other by a transformer and operated independently from each other in parallel, the power output operation continues even if one of the power supply circuits fails A parallel power supply system comprising the following configurations (11) to ( 14 ):
(11) Each power supply circuit controls switching of the input current energized to the primary side of the power output transformer by a plurality of current control elements, and the output of each power supply circuit is taken out from the secondary side of the power output transformer, respectively. It is synthesized in parallel.
(12) Each of the plurality of current control elements in each power supply circuit is controlled in operation by a control signal transmitted through a signal input transformer in which the primary coil and the secondary coil are insulated.
(13) The signal input transformer has a plurality of secondary coils with respect to one primary coil, and a control signal transmitted to each secondary coil is distributed to the current control elements in a plurality of power supply circuits. Input.
( 14 ) The primary side of the output transformer and the secondary coil of the signal input transformer are insulated from each other between the power supply circuits. 2. The parallel power supply system according to claim 1, wherein the following (21) to (23) are provided.
(21) Each power supply circuit uses a plurality of current control elements whose operations are controlled by a plurality of control signals at independent timings with a time difference from each other, and controls the switching of the input current supplied to the primary side of the power output transformer. To do.
(22) The signal input transformer is provided with a plurality of control signals having different on / off control timings, and each has a plurality of secondary coils corresponding to the number of the power supply circuits.
(23) The current control elements in each power supply circuit are controlled in operation at independent timings having a time difference from each other by a control signal branched to the secondary coil of the signal input transformer.   3. The parallel power supply system according to claim 1, wherein each power supply circuit is configured by using two current control elements.   4. The parallel power supply system according to claim 1, wherein the current control element in each power supply circuit forms a push-pull type output circuit.   4. The parallel power supply system according to claim 1, wherein the current control element in each power supply circuit forms a forward output circuit.   In any one of claims 1 to 5, the output of each power supply circuit is taken out from the secondary side of the power output transformer, rectified, passed through a ripple filter, and then connected to a common smoothing capacitor. A parallel power supply system characterized by being combined into one power supply output.   7. The parallel power supply system according to claim 1, wherein each of the current control elements in each power supply circuit is a MOS transistor.   7. A parallel power supply system according to claim 1, wherein each of the current control elements in each power supply circuit is a bipolar transistor.   7. The parallel power supply system according to claim 1, wherein each of the current control elements in each power supply circuit is an insulated gate bipolar transistor.   10. The parallel power supply system according to claim 1, wherein the output of each power supply circuit is rectified by a diode element having rectification characteristics.   11. The parallel power supply system according to claim 1, wherein the output of each power supply circuit is rectified by a synchronous rectifier circuit using a transistor.   12. The parallel power supply system according to claim 11, wherein the synchronous rectifier circuit is configured using a MOS transistor.   13. The parallel power supply system according to claim 1, wherein each power supply circuit performs switching control of input current at a high frequency.

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