JP3216736B2 - Converter circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention converts a single-phase AC input into a high-frequency AC, applies it to a primary winding of a transformer, and rectifies the voltage of the secondary winding of the transformer to obtain a DC output. Power supply,
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a converter circuit as a so-called insulated AC / DC converter, and more particularly to a converter circuit capable of improving conversion efficiency and converting an AC input current into a sine wave with a high power factor.

[0002] In the drawings, the same reference numerals indicate the same or corresponding parts.

[0003]

2. Description of the Related Art As a conventional converter circuit of this kind, a configuration of a so-called SMR converter disclosed in the following document is well known (SMR is a switching M
ode Rectifier). An SMR Topology with S
uppressed DC Link Components and Predictive LineCu
rrent Waveshaping; IEEE TRANSACTIONS ON INDUSTRY AP
PLICATIONS, VOL.IA-23, NO.4, JULY / AUGUST, 1987 FIG. 5 shows the configuration of this converter. In FIG. 1, an AC reactor 1 is connected between one of the AC inputs of a bridge rectifier circuit composed of diodes 2 to 5 and an AC input terminal U.
And an AC input terminal V is connected to the other AC input of the bridge rectifier circuit. The positive side of the DC output of the bridge rectifier circuit is connected to the intermediate tap o1 of the primary winding of the transformer 10, and the negative side of the DC output of the bridge rectifier circuit has one terminal of the switching elements 6 and 7 ( In this figure, the source terminal is connected and the transformer 10
Is connected to the other terminal (here, the drain terminal) of the switching element 6, and similarly, the other terminal v1 of the primary winding of the transformer 10 is connected to the other terminal of the switching element 7. (Here, the drain terminal). Next, one terminal u2 of the secondary winding of the transformer 10
Is connected to the anode of a diode 11, and the other terminal v2 of the secondary winding of the transformer 10 is also connected to a diode 12
Is connected to the connection point between the cathode of the diode 11 and the cathode of the diode 12. The positive terminal of the smoothing capacitor 13 is connected to the intermediate tap o2 of the secondary winding of the transformer 10. The terminals are connected, and the positive terminal of the capacitor 13 is connected to the DC output positive terminal P, and the negative terminal of the capacitor 13 is also connected to the DC output terminal N.

In such a configuration, an AC input terminal U
Is higher than the voltage of the AC input terminal V, when the switching elements 6 and 7 are turned on at the same time, the exciting inductance of the transformer 10 becomes zero and becomes the same as the short-circuit state.
The current passes through the path of the AC input terminal U → AC reactor 1 → Diode 2 → Primary winding intermediate tap o1 of the transformer 10, one of which passes from the primary winding u1 terminal of the transformer 10 to the switching element 6. And the other shunts into the primary winding v1 terminal of the transformer 10 or a path passing through the switching element 7, and then merges again to follow the path from the diode 5 to the AC input terminal V. At this time, no voltage is generated in the secondary winding of transformer 10 and excitation energy is accumulated in AC reactor 1.

When the switching element 7 is turned off in this state, the current path through the primary winding of the transformer 10
There is only a path passing through the zero intermediate tap o1 and one terminal u1, the transformer 10 is excited, a voltage is also generated in the secondary winding, the diode 11 becomes conductive, and the smoothing capacitor 13 is charged. Next, when the switching elements 6 and 7 are simultaneously turned on again, the exciting inductance of the transformer 10 becomes zero and becomes the same as the short-circuit state as described above, and a voltage is generated in the secondary winding of the transformer 10. In addition, the excitation energy is accumulated in the AC reactor 1.

When the switching element 6 is turned off in this state, the primary winding intermediate taps o1 and o1 of the transformer 10 are turned off.
One terminal v1 of the secondary winding is excited, a voltage is generated in the secondary winding of the transformer 10, and the diode 12 is turned on, and the smoothing capacitor is charged. When the voltage of the AC input terminal V is larger than the voltage of the U, the current passes through the path of the AC input terminal V → the diode 4 → the primary winding intermediate tap o1 of the transformer 10; The path from the primary winding u1 terminal to the switching element 6 and the other path from the primary winding v1 terminal of the transformer 10 to the switching element 7
The operation is the same as that described above except that the current flows only through the path from the diode 3 → the AC reactor 1 → the U terminal.

By repeating such an operation, a voltage having a frequency higher than the frequency of the AC input is applied to the transformer 10, thereby realizing high-frequency insulation conversion. Further, by turning on / off the switching elements 6 and 7 so that the current of the AC reactor 1 has the same phase as that of the AC input voltage and has a sinusoidal waveform, the power factor of the AC input can be made substantially unity. it can.

[0008]

However, in the circuit configuration shown in FIG. 5, two semiconductor elements (2 and 5, or 4 and 3) and a switching element allow a current to pass when the energy is stored in the AC reactor 1. Element 6,
7 and the semiconductor elements through which the current passes when transferring energy to the secondary side via the transformer 10 are two diodes (2 and 5, or 4 and 3) and one switching element (6 or 7). ), The loss generated in the semiconductor element is large, and (1) the conversion efficiency is reduced and the running cost is increased.

(2) The cooling device for the semiconductor element becomes large in size, and the whole power supply device cannot be downsized. There was a problem to say.
SUMMARY OF THE INVENTION It is an object of the present invention to provide a small, high-efficiency converter circuit that can reduce the generation loss, reduce the running cost, and can use a small-sized semiconductor device cooling device.

[0010]

According to a first aspect of the present invention, there is provided a converter circuit for converting a single-phase alternating current (inputs U, V, etc.) into a high-frequency alternating current and converting the single-phase alternating current into an intermediate tap of a transformer. (O1) applied to the primary winding, and rectifies the output voltage of the secondary winding of this transformer via a double-wave rectifier circuit having a capacitor (13 or the like) between its own DC output terminals. In the converter circuit, a bridge circuit including first to fourth four switching elements, wherein an anode of a first diode (2 or the like) and a cathode of a second diode (3 or the like) are connected, , A second two switching elements (8, 9 etc.) on the DC positive terminal side and a third and fourth two switching elements (6, 7 etc.) on the DC negative terminal side. Positive electrode terminal and the first Connecting the cathode of the diode,
A DC negative electrode terminal of the bridge circuit is connected to an anode of the second diode, and two AC terminals of the bridge circuit are connected to both ends (u1, v1, etc.) of the primary winding of the transformer.
, And the single-phase AC power supply is connected via an AC reactor (1 or the like) between a connection point between the first and second diodes and an intermediate tap of the primary winding of the transformer. To do it.

According to a second aspect of the present invention, there is provided the converter circuit according to the first aspect, wherein the first and second converter circuits are provided.
When the potential of the connection point between the two diodes is higher than the potential of the intermediate tap of the primary winding of the transformer, the first and second switching elements are interposed between the simultaneous ON periods of the two elements. While turning on and off alternately,
When the potential of the connection point between the first and second diodes is lower than the potential of the intermediate tap of the primary winding of the transformer, the third and fourth switching elements are simultaneously turned on. Is repeatedly turned on / off alternately with the period of.

Further, in the converter circuit of the present invention, a single-phase alternating current (input U, V, etc.) is converted into a high-frequency alternating current and applied to a primary winding having an intermediate tap (o1, etc.) of a transformer,
In a converter circuit for rectifying and taking out the output voltage of the secondary winding of this transformer via a double-wave rectifier circuit having a first capacitor (13 etc.) between its own DC output terminals, a first diode (2 etc.) ) Is connected to the cathode of a second diode (such as 3), and the first to fourth 4
A bridge circuit comprising two switching elements,
A bridge circuit having first and second two switching elements (8, 9 etc.) on the DC positive terminal side and having third and fourth two switching elements (6, 7 etc.) on the DC negative terminal side The DC positive terminal is connected to the cathode of the first diode, the DC negative terminal of the bridge circuit is connected to the anode of the second diode, and the two AC terminals of the bridge circuit are connected to the transformer 1 The single-phase AC power source is connected between both ends (u1, v1, etc.) of the secondary winding and between a connection point between the first and second diodes and an intermediate tap of the transformer primary winding. And a DC reactor (15 or the like) is inserted between any one of the DC output terminals of the double-wave rectifier circuit and the terminal of the first capacitor connected to this terminal.

In the converter circuit according to a fourth aspect of the present invention, in the converter circuit according to the third aspect, a second capacitor (14 or the like) is connected between the single-phase AC power sources, and the second capacitor is connected to the single-phase AC power source. An AC reactor (1 or the like) is inserted into the power supply line looking at the phase AC power supply side.
In the converter circuit according to a fifth aspect, in the converter circuit according to the third or fourth aspect, a potential at a connection point between the first and second diodes is a potential at an intermediate tap of the primary winding of the transformer. When it is higher, the first and second switching elements are alternately turned on / off alternately while interposing the simultaneous off period of the two elements as necessary, thereby repeating the first and second switching elements. When the potential of the connection point between the two diodes is lower than the potential of the intermediate tap of the primary winding of the transformer, the third and fourth switching elements require a period during which the two elements are simultaneously turned off. The on / off operation is alternately repeated while being interposed therebetween.

In the converter circuit of the present invention, a single-phase alternating current (input U, V, etc.) is converted into a high-frequency alternating current and applied to a primary winding having an intermediate tap (O1, etc.) of a transformer. In a converter circuit for taking out the output voltage of the secondary winding of this transformer via a dual-wave rectifier circuit having a capacitor (13 or the like) between its own DC output terminals, six switching elements (6 to 9, 21, 22) ) And a diode (2, 3, 23 to 26, etc.) connected in anti-parallel to each of all the switching elements, and is a bridge circuit having first to third three arm pairs. Connecting two AC terminals of the second and third arm pairs (consisting of switching 6-9, diodes 23-26, etc.) to both ends (u1, v1, etc.) of the transformer primary winding, respectively;
An AC reactor (1 or the like) between an AC terminal of the first arm pair and an intermediate tap of the primary winding of the transformer (comprising switching elements 21 and 22 and diodes 2 and 3); Connect a single-phase AC power supply.

[0015]

(1) Regarding the invention according to claims 1 to 5, a half bridge circuit composed of two diodes and 4
A full bridge circuit composed of three switching elements is connected in parallel, two AC terminals of the full bridge circuit are connected to both ends of a primary winding with an intermediate tap of a transformer, respectively, and an AC terminal of the half bridge circuit is connected to a transformer. A single-phase alternating current is applied between the intermediate tap of the primary winding of the device and the number of semiconductor elements in the primary current path is two, one diode and one switching element. Downsize.

(2) Regarding the invention according to claim 6, all the arms are bridge-connected with three sets of arm pairs in which switching elements and diodes are connected in anti-parallel, and the AC terminals of two of the arm pairs are transformed. A single-phase alternating current is applied between the AC terminal of the remaining pair of arm pairs and the primary winding intermediate tap of the transformer via an AC reactor. With this configuration, the number of semiconductor elements in the primary current path is made two in total, one diode and one switching element, and the device is reduced in loss and size.

[0017]

FIG. 1 is a block diagram showing an embodiment according to the first and second aspects of the present invention. In the figure, a diode series connection circuit connecting the anode of the diode 2 and the cathode of the diode 3 and a bridge circuit composed of four switching elements 6 to 9 are connected in parallel. The AC reactor 1 is connected to one terminal U, and one terminal u1 of the primary winding of the transformer 10 is connected to a series connection point of the switching element 8 and the switching element 6.
The other terminal v1 of the primary winding of the transformer 10 is connected to a series connection point of the switching element 9 and the switching element 8,
An AC input terminal V is connected to an intermediate tap o1 of the primary winding of the transformer 10.

One terminal u of the secondary winding of the transformer 10
2, the anode of the diode 11 is connected to the other terminal v2 of the secondary winding, and the anode of the diode 12 is connected to the connection point between the cathode of the diode 11 and the cathode of the diode 12. The positive terminal is connected to the intermediate tap o2 of the secondary winding of the transformer 10, and the negative terminal of the capacitor 13 is connected to the DC output positive terminal P.
The negative terminal 3 is connected to the DC output terminal N.

In such a configuration, the AC input terminal U
Is higher than the voltage of the AC input terminal V, when the switching elements 8 and 9 are turned on at the same time, the exciting inductance of the transformer 10 becomes zero and becomes the same as the short-circuit state.
The current follows the path of the U terminal → the AC reactor 1 → the diode 2, one of which passes through the switching element 8 from the u1 terminal of the primary winding of the transformer 10 to the intermediate tap o 1 of the primary winding of the transformer 10. And a path through the switching element 9 to the path from the terminal v1 of the primary winding of the transformer 10 to the intermediate tap o1 of the primary winding of the transformer 10, and then merge again. It flows toward the AC input terminal V. At this time, no voltage is generated in the secondary winding of transformer 10 and excitation energy is accumulated in AC reactor 1. When the switching element 9 is turned off in this state, the current path through the primary winding of the transformer 10 becomes only the path from one terminal u1 of the primary winding of the transformer 10 to the intermediate tap o1, and the current path through the transformer 10 Is excited, a voltage is also generated in its secondary winding, the diode 11 becomes conductive, and the smoothing capacitor 13 is charged. Next, when the switching elements 8 and 9 are simultaneously turned on, the exciting inductance of the transformer 10 becomes zero and becomes the same as the short-circuit state as described above,
No voltage is generated in the secondary winding of the transformer 10, and excitation energy is stored in the AC reactor 1. When the switching element 8 is turned off in this state, the transformer 10
The current path through the primary winding of the
1 only passes through the intermediate tap o1, and the transformer 1
0 is excited, a voltage is also generated in the secondary winding, the diode 12 is turned on, and the smoothing capacitor 13 is charged. When the voltage of the AC input terminal V is larger than the voltage of the AC input terminal U, for example, when the AC reactor 1 is energized, the current flows through the path from the AC input terminal V to the intermediate tap o1 of the primary winding of the transformer 10. After passing, one is transformer 10
Of the primary winding of the transformer 10 through the switching element 6 and the other branch from the terminal v1 of the primary winding of the transformer 10 through the switching element 7, and then merge again to form a diode. 3 → AC reactor 1 → AC input terminal U
Other operations are the same as those described above, except that the flow only follows the path.

By repeating such an operation, a voltage having a frequency higher than the frequency of the AC input is applied to the primary winding of the transformer 10, thereby realizing high-frequency insulation conversion. The power factor of the AC input becomes approximately 1 by turning on / off the switching elements 6 to 9 so that the current of the AC reactor 1 has the same phase as the AC input voltage and becomes sinusoidal. .

FIG. 2 is a block diagram showing an embodiment according to the third, fourth and fifth aspects of the present invention. FIG. 3 is different from FIG. 1 in that a capacitor 14 is provided between a series connection point of diodes 2 and 3 and an AC input terminal V, and the cathodes of diodes 11 and 12 on the secondary side of transformer 10 are different from each other. DC reactor 15 between the connection point of
Is provided.

The system shown in FIG. 1 uses the energy stored in the AC reactor 1 when the switching elements 8 and 9 or 6 and 7 are simultaneously turned on, and attaches the transformer 10 by turning off the switching elements 8 or 9 or 6 or 9. In contrast to the so-called current input system, the system of FIG. 2 uses the capacitor 14 as a voltage source to energize the transformer 10 by alternately turning on the switching elements 8 and 9 or alternately turning on the switching elements 6 and 7. That is, a so-called voltage input method is used. In this case, the AC reactor 1 and the capacitor 14 are not essential in principle. However, as a practical circuit, the AC reactor 1 and the capacitor 14 are required as a low-pass filter for preventing a high-frequency current from flowing to the AC power supply UV side.

Next, the operation of FIG. 2 will be described. When the switching element 8 is turned on when the voltage of the AC input terminal U is higher than the voltage of the AC input terminal V, the transformer 10 turns on the primary winding u.
Excited between 1-o1, a voltage is induced in the secondary winding of the transformer, the diode 11 conducts, a current flows through the DC reactor 15, and the smoothing capacitor 13 is charged. Next, when all four switching elements are turned off, the current of the DC reactor 15 passes through the capacitor 13, and one of the paths passes from the intermediate tap o 2 of the secondary winding of the transformer 10 to one terminal u 2 → the diode 11. And the other flows back from the intermediate tap o2 of the secondary winding of the transformer 10 to the other terminal v2 → a path through the diode 12.

Next, when the switching element 9 is turned on,
The transformer 10 is excited between the primary windings v1-o1, a voltage is induced in the secondary winding of the transformer, the diode 12 conducts, the current flows through the DC reactor 15, and the smoothing capacitor 13 is charged. Next, when all four switching elements are turned off, the current of the DC reactor 15 passes through the capacitor 13, and one of the paths passes from the intermediate tap o 2 of the secondary winding of the transformer 10 to one terminal u 2 → the diode 11. And the other flows back from the intermediate tap o2 of the secondary winding of the transformer 10 to a path passing through the other terminal v2 → the diode 12.

When the voltage at the AC input terminal V is higher than the voltage at the AC input terminal U, the same result as described above can be obtained by alternately turning on / off the switching elements 6 and 7. By repeating such an operation, a voltage having a frequency higher than the frequency of the AC input is applied to the transformer 10, and high-frequency insulation conversion is realized. The power factor of the AC input is reduced to approximately 1 by turning on / off the switching elements 6 to 9 so that the current of the AC reactor has the same phase as the AC input voltage and has a sine wave shape. Become.

Next, FIG. 3 shows a first embodiment of the invention according to claim 6. In the figure, diodes 2, 3, 23, 24, 25, and 26 are connected in anti-parallel to six switching elements 21, 22, 8, 6, 9, and 7, respectively. 21 and 22),
A bridge circuit is formed by three pairs of arms (8 and 6) and (9 and 7), and an AC terminal of an arm pair including switching elements 21, 22, and diodes 2, 3 and one terminal U of the AC input are connected to a bridge circuit. An AC reactor 1 is connected between the two terminals, and one terminal u1 of the primary winding of the transformer 10 is connected to an AC terminal of an arm pair including the switching elements 8, 6 and the diodes 23, 24.
And switching elements 9 and 7, a diode 25,
The other terminal v1 of the primary winding of the transformer 10 is connected to the AC terminal of the arm pair consisting of 26, and the AC input terminal V is connected to the intermediate tap o1 of the primary winding of the transformer 10. I have.

One terminal u of the secondary winding of the transformer 10
2, the anode of the diode 11 is connected to the other terminal v2 of the secondary winding, and the anode of the diode 12 is connected to the connection point between the cathode of the diode 11 and the cathode of the diode 12. The positive terminal is connected to the intermediate tap o2 of the secondary winding of the transformer 10, and the negative terminal of the capacitor 13 is connected to the DC output positive terminal P.
The negative terminal 3 is connected to the DC output negative terminal N, respectively.

In such a configuration, when the switching element 22 is turned on when the voltage of the AC input terminal U is higher than the voltage of the AC input terminal V, the current flows through the path from the U terminal → the AC reactor 1 → the switching element 22. Following this, one goes from the u1 terminal of the primary winding of the transformer 10 via the diode 24 to the intermediate tap o1 of the primary winding of the transformer 10
To the transformer 10 via the diode 26
Of the primary winding from the terminal v1 of the primary winding to the intermediate tap o1 of the primary winding of the transformer 10, and then merges again and flows toward the AC input terminal V. At this time, the exciting inductance of the transformer 10 becomes zero and becomes the same as the short-circuit state, no voltage is generated in the secondary winding of the transformer 10, and the exciting energy is accumulated in the AC reactor 1.

In this state, when the switching element 8 is turned on and then the switching element 22 is turned off, the current is U terminal → AC reactor 1 → diode 2 → switching element 8 → u1 terminal of transformer 10 → transformer 10 o1
A current path commutating from the terminal to the V terminal and passing through the primary winding of the transformer 10 is one terminal u1 of the primary winding of the transformer 10.
From the transformer 10 to the intermediate tap o1.
Is excited, a voltage is also generated in its secondary winding, the diode 11 becomes conductive, and the smoothing capacitor 13 is charged. Next, when the switching element 22 is turned on, the exciting inductance of the transformer 10 becomes zero as described above and becomes the same as the short-circuit state, no voltage is generated in the secondary winding of the transformer 10, and Excitation energy is stored in the reactor 1. In this state, the switching element 8 is
When the switching element 9 is turned on when the switching element 9 is turned on, the current path through the primary winding of the transformer 10 becomes only a path from one terminal v1 of the transformer 10 to the intermediate tap o1, and the transformer 10 is excited and A voltage is also generated in the next winding, and the diode 12 is turned on, and the smoothing capacitor 13
Is charged.

When the voltage at the AC input terminal V is higher than the voltage at the AC input terminal U, the switching elements 21, 6, and 7 are replaced with the switching elements 22, 8, and 7, respectively, because of the positive / negative symmetry of the circuit. Instead of the diodes 2, 24 and 26, the diodes 3, 23 and 25 perform the same operation as described above. By repeating such an operation, a voltage having a frequency higher than the frequency of the AC input is applied to the primary winding of the transformer 10, thereby realizing high-frequency insulation conversion. ON / OFF of the switching elements 21, 22, 6 to 9
The power factor of the AC input becomes approximately 1 by performing the operation so that the current of the AC reactor 1 has the same phase as the AC input voltage and has a sinusoidal waveform.

FIG. 4 shows a second embodiment of the present invention. The difference from FIG. 3 is that the secondary side rectifier diode 1
The only difference is that switching elements 27 and 28 are added in antiparallel to 1 and 12, respectively. The operation is the same as that of FIG. 3, and the components having the same numbers perform the same operation. Further, the switching element 27 performs ON / OFF in synchronization with the switching elements 8 and 7,
The switching element 28 performs ON / OFF in synchronization with the switching elements 6 and 9. Here, ON / OFF of switching elements 21, 22, 6-9 and 27, 28
By adjusting the method, the AC input current can be controlled at an arbitrary phase and an arbitrary waveform, and can also have a function as a so-called harmonic compensator (active filter). Further, it goes without saying that this device can function as a high-frequency insulating DC / AC converter (inverter).

[0032]

According to the first and second aspects of the present invention, when energy is stored in the AC reactor 1, a parallel circuit of one diode (2 or 3) and two switching elements (parallel of 8 and 9 or 6 When a current flows and the energy is released to the secondary side of the transformer, only one diode and one switching element flow the current. Since the number of elements passing through is reduced and the generated loss is reduced, the cooling efficiency can be improved and the cooling device can be downsized.
Price can be reduced.

Also in the inventions according to the third, fourth and fifth aspects, the configuration of the semiconductor circuit and the number of semiconductor elements in the current path on the primary side of the transformer are the same as those of the first and second aspects of the present invention. The effect of is obtained. Also in the invention according to claim 6, when energy is stored in the AC reactor 1, a parallel circuit of one switching element (21 or 22) and two diodes (parallel circuit of 23 and 25 or 2
4 and 26 in parallel), and when discharging energy to the secondary side of the transformer, only one diode and one switching element flow current. Since the number of elements passing through decreases and the generation loss decreases, the conversion efficiency can be improved, and at the same time, the cooling device can be downsized, and the entire device can be reduced in size and cost.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration as an embodiment of the invention according to claims 1 and 2;

FIG. 2 is a circuit diagram showing a configuration as an embodiment of the invention according to claims 3, 4, and 5;

FIG. 3 is a circuit diagram showing a configuration as a first embodiment of the invention according to claim 6;

FIG. 4 is a circuit diagram showing a configuration as a second embodiment of the invention according to claim 6;

FIG. 5 is a circuit diagram of a conventional converter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 AC reactor 2 Diode 3 Diode 6 Switching element 7 Switching element 8 Switching element 9 Switching element 10 Transformer 11 Diode 12 Diode 13 Smoothing capacitor 14 Capacitor 15 DC reactor 21 Switching element 22 Switching element 23 Diode 24 Diode 25 Diode 26 Diode 27 Switching element 28 Switching element

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02M 7/219

Claims (6)

(57) [Claims] 1. A single-phase alternating current is converted to a high-frequency alternating current and applied to a primary winding with an intermediate tap of a transformer.
In a converter circuit for taking out the output voltage of the next winding via a double-wave rectifier circuit having a capacitor between its own DC output terminals, an anode of a first diode and a cathode of a second diode are connected, A bridge circuit comprising four fourth switching elements, wherein the first and second two switching elements are provided on a DC positive terminal side, and the third and fourth two switching elements are provided on a DC negative terminal side. Connecting the DC positive terminal of the bridge circuit to the cathode of the first diode; connecting the DC negative terminal of the bridge circuit to the anode of the second diode; connecting the two AC terminals of the bridge circuit to the AC terminal An AC rear terminal connected between both ends of the transformer primary winding, and a connection point between the first and second diodes and an intermediate tap of the transformer primary winding; Converter circuit, characterized in that connect the power of the single-phase AC through Torr. 2. The converter circuit according to claim 1, wherein when a potential at a connection point between the first and second diodes is higher than a potential at an intermediate tap of the primary winding of the transformer, the first circuit is connected to the first diode. , The second switching element is alternately turned on / off alternately with the simultaneous on period of the two elements interposed therebetween, and the potential at the connection point between the first and second diodes is changed by the transformation. When the potential is lower than the potential of the intermediate tap of the primary winding of the switch, the third and fourth switching elements are repeatedly turned on / off alternately with the simultaneous on period of the two elements interposed therebetween. A converter circuit characterized in that: 3. A single-phase alternating current is converted into a high-frequency alternating current and applied to a primary winding with an intermediate tap of the transformer.
In a converter circuit for taking out the output voltage of the next winding via a dual-wave rectifier circuit having a first capacitor between its own DC output terminals, an anode of a first diode and a cathode of a second diode are connected; A bridge circuit comprising first to fourth switching elements, wherein the first, second, and second switching elements are
Holding three switching elements on the DC positive terminal side,
Connecting the DC positive terminal of the bridge circuit having the fourth two switching elements on the DC negative terminal side to the cathode of the first diode; and connecting the DC negative terminal of the bridge circuit and the anode of the second diode to each other. And connecting two AC terminals of the bridge circuit to both ends of the transformer primary winding, respectively, and a connection point between the first and second diodes and an intermediate point between the transformer primary windings. The single-phase AC power supply was connected between the tap and a tap, and a DC reactor was inserted between any one of the DC output terminals of the double-wave rectifier circuit and the terminal of the first capacitor connected to this terminal. A converter circuit characterized by the above. 4. A converter circuit according to claim 3, wherein a second capacitor is connected between said single-phase AC power supplies, and said second capacitor is connected to a power supply line as viewed from said single-phase AC power supply side. A converter circuit having a reactor inserted. 5. The converter circuit according to claim 3, wherein a potential at a connection point between the first and second diodes is higher than a potential at an intermediate tap of the primary winding of the transformer. Repeating the on / off of the first and second switching elements alternately while interposing the simultaneous off period of the two elements as necessary, When the potential of the connection point is lower than the potential of the intermediate tap of the primary winding of the transformer, the third and fourth switching elements are connected between the two elements at the same time, if necessary. A converter circuit characterized in that it alternately turns on and off while being sandwiched. 6. A single-phase alternating current is converted into a high-frequency alternating current and applied to a primary winding having an intermediate tap of a transformer, and an output voltage of a secondary winding of the transformer is applied between its own DC output terminals. A converter circuit that takes out via a double-wave rectifier circuit having a capacitor, comprising: six switching elements; and diodes connected in anti-parallel to all of the switching elements.
A bridge circuit having third to third arm pairs, wherein two AC terminals of the second and third arm pairs are respectively connected to both ends of the transformer primary winding; A converter circuit, wherein the single-phase AC power source is connected between a pair of AC terminals and an intermediate tap of the transformer primary winding via an AC reactor.