JPH11252919A - Bidirectional dc-to-dc converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To bidirectionally supply a stabilized constant-voltage power by providing a switch circuit at both sides of the primary coil winding and the secondary coil winding of a transformer and switching the input and output sides as needed. SOLUTION: When the left side of a bidirectional DC-to-DC converter 14 is set as an input, the right side of a transformer 6 is set as an output circuit. When a switch circuit 1a is off, reflux is made by a diode 5b and a choke coil 3b, and smoothing is made by a capacitor 2b before outputting to the right side of the bidirectional DC-to-DC converter 14. At this time, a switch circuit 1b is fixed to off state, a voltage feedback passes through an insulation-type voltage detection circuit 8b, a control circuit 9 with an input/output switching function drives the switch circuit 1a via an insulation-type drive circuit 7a, thus controlling the on width of the switch circuit 1a. Also when the right and left side of the bidirectional DC/DC converter 14 are set to input and output respectively, the operation is completely reversed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC / DC converter for converting an unstable input voltage into a stable output voltage, without changing the connection between the input side and the connection on the output side. Bidirectional D capable of supplying power from the output side to the output side and power supply from the output side to the input side
It relates to a C / DC converter.

[0002]

2. Description of the Related Art FIG. 5 shows a system configuration of an uninterruptible power supply system using a conventional charger and a DC / DC converter, where 11 is a primary power supply, 12 is a DC power supply, 13
Is a load, 15 is a rechargeable battery, 16 is a charger, 17 is DC
/ DC converter.

The operation of the system shown in FIG. 5 will be described below. Normally, the power from the primary power supply 11 is converted into stable DC power by the DC power supply 12 and supplied to the load 13, and at the same time, the rechargeable battery 15 is charged via the charger 16.
On the other hand, when the primary power supply 11 has to be stopped, for example, at the time of an instantaneous interruption or refueling of the power generator, the power of the rechargeable battery 15 is converted into stable DC power by the DC / DC converter 17. And supplies it to the load 13. Thus, in the system configuration using the charger and the DC / DC converter, the primary power supply 11 operates and the load 13
Power can continue to be supplied.

[0004]

The conventional charger and DC /
The uninterruptible power supply system using the DC converter is configured as described above. If the charger 16 is considered as one power supply, the DC power supply 12 and the charger 15 are used to supply continuous power to the load 13. And three DC / DC converters 17 are required, and the system configuration is complicated and large.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has a bidirectional DC / DC switchable between input and output instead of a charger and a DC / DC converter.
A converter is provided to further reduce the system configuration.

[0006]

A bidirectional DC / DC converter according to a first aspect of the invention is provided with a switch circuit, a rectifying / smoothing diode and a choke coil on each of a primary winding side and a secondary winding side of a transformer. When operation is performed, high-frequency switching is performed by a switch circuit provided in parallel with the series connection of the rectifier diode and choke coil, and when output operation is performed, the switch circuit provided in parallel with the series connection of the rectifier diode and choke coil is turned off. To perform a rectifying and smoothing operation.

Further, a bidirectional DC / DC according to the second invention is provided.
The converter provided a switching circuit, a rectifying / smoothing diode and a choke coil on each of the primary and secondary windings of the transformer, and provided a switching circuit and a diode in series on each of the primary and secondary sides. A rectifying / smoothing operation is provided by providing a lead wire for the switch circuit winding and performing a high-frequency switch by the switch circuit when performing an input operation, and fixing the switch circuit to an OFF state when performing an output operation. It is.

The bidirectional DC / DC according to the third invention
The converter has a switch circuit and a rectifier diode on each of the primary and secondary windings of the transformer, and when performing input operation, performs a high-frequency switch by a switch circuit provided in parallel with the rectifier diode, and outputs. When the operation is performed, the rectification operation is performed by fixing a switch circuit provided in parallel with the rectifying diode in an off state.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 4 shows a system configuration of an uninterruptible power supply system using a bidirectional DC / DC converter according to Embodiment 1 of the present invention, where 11 is a primary power supply, 12 is a DC power supply, 13 is a load, and 14 is a load. The bidirectional DC / DC converter 15 is a rechargeable battery.

The operation of the system shown in FIG. 4 will be described below. During normal primary power supply operation, the power from the primary power supply 11 is converted into stable DC power by the DC power supply 12 and supplied to the load 13, and at the same time, the rechargeable battery 15 is converted via the bidirectional DC / DC converter 14. Charge. Also, primary power supply 1
When the power of the rechargeable battery 15 must be stopped, the power of the rechargeable battery 15 is converted into stable DC power by switching the input and output of the bidirectional DC / DC converter 14 and supplied to the load 13. Thus, instead of the two chargers and DC / DC converters used in the conventional uninterruptible power supply system, one bidirectional converter can continue to supply stable power to the load 13. .

FIG. 1 shows a bidirectional DC / DC converter according to a first embodiment of the present invention.
b is a switch circuit, 2a and 2b are capacitors, 3a and 3
b is a choke coil, 4a, 4b, 5a and 5b are diodes, 6 is a transformer, 7a and 7b are insulated drive circuits, 8
Reference numerals a and 8b denote isolated voltage detection circuits, 9 denotes a control circuit with an input / output switching function, and 14 denotes a bidirectional DC / DC converter.

In the bidirectional DC / DC converter shown in FIG. 1, when the left side of the bidirectional DC / DC converter 14 is used as an input, the capacitor 2a serves as an input capacitor, and the switch circuit 1a connected in series to the transformer 6 , The power is converted by the transformer 6. The right side of the transformer 6 is an output circuit, which performs rectification by the diode 4b. When the switch circuit 1a is off, reflux is performed by the diode 5b and the choke coil 3b.
The signal is smoothed by the capacitor 2b and output to the right side of the bidirectional DC / DC converter 14. At this time, the switch circuit 1b is fixed to the OFF state, the voltage feedback is passed through the insulation voltage detection circuit 8b, and the control circuit 9 with the input / output switching function drives the switch circuit 1a via the insulation drive circuit 7a. Control the ON width of the output voltage to stabilize the output voltage.

Conversely, even when the right side of the bidirectional DC / DC converter 14 is set as the input and the left side is set as the output, the operation is completely opposite to the above-mentioned operation. That is, the capacitor 2b serves as an input capacitor, and performs power conversion by the transformer 6 by switching the switch circuit 1b connected in series with the transformer 6, and rectifies by the diode 4a.
When the switch circuit 1b is off, the current is returned by the diode 5a and the choke coil 3a, smoothed by the capacitor 2a, and output to the left side of the bidirectional DC / DC converter 14. Similarly, at this time, the switch circuit 1a is fixed to the OFF state, the voltage feedback is passed through the insulation type voltage detection circuit 8a, and the insulation type drive circuit 7b
Drives the switch circuit 1b through the switch circuit 1b.
Control the ON width of the output voltage to stabilize the output voltage.

As described above, bidirectional power can be supplied by switching between input and output by an external signal. For example, as shown in FIG. If provided between them, the function of a charger for the rechargeable battery 15 and the function of a DC / DC converter for supplying constant voltage power to the load 13 can be obtained.

Embodiment 2 FIG. 2 shows a bidirectional DC / DC converter according to Embodiment 2 of the present invention, in which 1a, 1b, 2a, 2b, 3a, 3b, 4a, 4
b, 5a, 5b, 6, 7a, 7b, 8a, 8b, 9, 1
4 is the same as FIG. 1, and 10a and 10b are diodes.

In the bidirectional DC / DC converter shown in FIG. 2, when the left side of the bidirectional DC / DC converter 14 is used as an input, the capacitor 2a serves as an input capacitor, and the switch circuit 1a connected in series with the transformer 6 , The power is converted by the transformer 6, and the diode 10a prevents reverse current. The right side of the transformer 6 is an output circuit, which performs rectification by the diode 4b. When the switch circuit 1a is off, the diode 5b
And the choke coil 3b performs reflux, and the capacitor 2b
And outputs it to the right side of the bidirectional DC / DC converter 14. At this time, the switch circuit 1b is fixed to the off state,
The voltage feedback is performed through the isolated voltage detection circuit 8b.
The control circuit 9 with the input / output switching function drives the switch circuit 1a via the insulating drive circuit 7a, controls the ON width of the switch circuit 1a, and stabilizes the output voltage.

Conversely, even when the right side of the bidirectional DC / DC converter 14 is set as the input and the left side is set as the output, the operation described above is completely reversed. That is, the capacitor 2b serves as an input capacitor, and performs power conversion by the transformer 6 by switching the switch circuit 1b connected in series with the transformer 6, and rectifies by the diode 4a.
When the switch circuit 1b is off, the current is returned by the diode 5a and the choke coil 3a, smoothed by the capacitor 2a, and output to the left side of the bidirectional DC / DC converter 14. Similarly, at this time, the switch circuit 1a is fixed to the OFF state, the voltage feedback is passed through the insulation type voltage detection circuit 8a, and the insulation type drive circuit 7b
Drives the switch circuit 1b through the switch circuit 1b.
Control the ON width of the output voltage to stabilize the output voltage. The diode 10b in this case is also for preventing a reverse current.

As described above, the circuit operation is almost the same as that of the first embodiment, and also in this case, the circuit is provided between the line of the DC power supply 12 and the load 13 and the rechargeable battery 15 as shown in FIG. For example, a function of a charger for the rechargeable battery 15 and a function of a DC / DC converter for supplying constant voltage power to the load 13 can be obtained. In the configuration of the second embodiment, the switch circuits 1a,
1b and the windings of the transformer 6 connected to the diodes 4a and 4b for rectification, the power conversion from the left side to the right side of the bidirectional DC / DC converter 14 is performed. DC / DC converter 14
Can be operated even if the voltage ratio in the power conversion from the right side to the left side is greatly different.

Embodiment 3 FIG. 3 shows a bidirectional DC / DC converter according to Embodiment 3 of the present invention, in which 1a, 1b, 2a, 2b, 4a, 4b, 6, 7a,
7b, 8a, 8b, 9, and 14 are the same as those in FIG.

The bidirectional DC / DC converter shown in FIG. 3 is a flyback type power conversion circuit, and includes a bidirectional DC / DC converter.
When the left side of the DC converter 14 is used as an input, the capacitor 2a serves as an input capacitor, and the transformer 6 performs power conversion by switching a switch circuit 1a connected in series to the transformer 6. The right side of the transformer 6 is an output circuit, and the exciting energy stored in the transformer 6 is rectified by the diode 4b,
b, and outputs it to the right side of the bidirectional DC / DC converter 14. At this time, the switch circuit 1b is fixed to the off state, the voltage feedback is passed through the insulation type voltage detection circuit 8b, and the control circuit 9 with the input / output switching function is used as the insulation type drive circuit 7a.
Drives the switch circuit 1a through the
Control the ON width of the output voltage to stabilize the output voltage.

Conversely, even when the right side of the bidirectional DC / DC converter 14 is set as the input and the left side is set as the output, the operation described above is completely reversed. That is, the capacitor 2b serves as an input capacitor, performs power conversion by the transformer 6 by switching the switch circuit 1b connected in series to the transformer 6, and rectifies the excitation energy stored in the transformer 6 by the diode 4a. The signal is smoothed by the capacitor 2a and output to the left side of the bidirectional DC / DC converter 14. Similarly, at this time, the switch circuit 1a is fixed to the OFF state, the voltage feedback is passed through the insulation type voltage detection circuit 8a, and the control circuit 9 with the input / output switching function is used for the insulation type drive circuit 7a.
b, the switch circuit 1b is driven through the switch circuit 1b.
By controlling the ON width of b, the output voltage is stabilized.

As described above, in the same manner as in the first and second embodiments, bidirectional power can be supplied by switching between input and output by an external signal. In this case, as shown in FIG. If provided between the line of the device 12 and the load 13 and the rechargeable battery 15, a function of a charger for the rechargeable battery 15 and a function of a DC / DC converter for supplying constant voltage power to the load 13 are obtained. Can be.

[0023]

Since the present invention is configured as described above, it has the following effects.

According to the first invention, a switch circuit is provided on both sides of the primary winding and the secondary winding of the transformer, and the input side and the output side are switched as necessary without changing the connection, thereby providing a plurality of switches. A stable constant voltage power can be supplied in both directions without using a power supply.

According to the second aspect, similarly to the first aspect, stabilized constant-voltage power can be supplied bidirectionally without using a plurality of power supplies.

According to the third aspect, similarly to the first aspect, stabilized constant-voltage power can be supplied bidirectionally without using a plurality of power supplies.

[Brief description of the drawings]

FIG. 1 is a diagram showing Embodiment 1 of a bidirectional DC / DC converter according to the present invention.

FIG. 2 is a diagram showing a bidirectional DC / DC converter according to a second embodiment of the present invention;

FIG. 3 is a diagram showing Embodiment 3 of a bidirectional DC / DC converter according to the present invention.

FIG. 4 is a diagram showing a system configuration example of an uninterruptible power supply system using a bidirectional DC / DC converter according to the present invention.

FIG. 5 is a diagram illustrating a system configuration example of an uninterruptible power supply system using a conventional DC / DC converter and a charger.

[Explanation of symbols]

1 switch circuit, 2 capacitor, 3 choke coil, 4 diode, 5 diode, 6 transformer,
Reference Signs List 7 insulated drive circuit, 8 insulated voltage detection circuit, 9 control circuit with input / output switching function, 10 diode, 11 primary power supply, 12 DC power supply, 13 load, 14 bidirectional DC / DC converter, 15 rechargeable battery, 16 charger, 17 DC / DC converter.

Claims (3)

[Claims] 1. A transformer having a primary winding and a secondary winding for performing power conversion, a first switch circuit connected to one end of the primary winding of the transformer, and a first switch circuit connected to the first switch circuit. A first diode having an anode connected to one end of a primary winding of the transformer, a first choke coil having one end connected in series with a cathode of the first diode, and a first switch circuit. A second switch circuit connected to one end of a secondary winding of the transformer having the same polarity as one end of a primary winding of the connected transformer, and a second switch circuit connected to the second switch circuit. A second diode having an anode connected to one end of the next winding; a second choke coil having one end connected in series with a cathode of the second diode; and a first choke coil for driving the first switch circuit. of A drive circuit, a second drive circuit for driving the second switch circuit, and an input / output switching function control having a function of switching between the first drive circuit and the second drive circuit and controlling a pulse width. A bidirectional DC / DC converter characterized by comprising a circuit. 2. A transformer having a primary winding and a secondary winding for performing power conversion, a first switch circuit connected to one end of the primary winding of the transformer, and a first switch circuit connected to the first switch circuit. An anode is connected to a line drawn from the middle of the winding of the primary winding of the transformer or a line drawn from an end of the winding on an extension of one end of the primary winding connected to the first switch circuit of the transformer. A first diode connected thereto, a first choke coil having one end connected in series with a cathode of the first diode, and one end of a primary winding of the transformer connected to the first switch circuit. A second switch circuit connected to one end of the secondary winding of the transformer having the same polarity, and a wire drawn out from the middle of the secondary winding of the transformer connected to the second switch circuit. Or the above A second diode having an anode connected to a line drawn from an end of the winding on an extension of one end of the secondary winding connected to the second switch circuit of the lance, and a cathode having one end connected to the second diode; A second choke coil connected in series with the first drive circuit, a first drive circuit for driving the first switch circuit, a second drive circuit for driving the second switch circuit, and the first drive circuit A bidirectional DC / DC converter comprising a circuit and a control circuit having an input / output switching function having a function of switching the second drive circuit and controlling a pulse width. 3. A transformer having a primary winding and a secondary winding for performing power conversion, a first switch circuit connected to one end of the primary winding of the transformer, and a first switch circuit connected to the first switch circuit. A first diode having an anode connected to one end of a primary winding of the transformer, and a secondary winding of the transformer having an opposite polarity to one end of the primary winding of the transformer connected to the first switch circuit. A second switch circuit connected to one end of a wire, a second diode having an anode connected to one end of a secondary winding of the transformer connected to the second switch circuit, and the first switch A first drive circuit for driving a circuit, a second drive circuit for driving the second switch circuit, and a function of switching between the first drive circuit and the second drive circuit and controlling a pulse width. I / O switching function And a control circuit.