WO2013137518A1

WO2013137518A1 - Bidirectional high-frequency resonator and bidirectional transformer using same

Info

Publication number: WO2013137518A1
Application number: PCT/KR2012/003679
Authority: WO
Inventors: 이준영; 한병문; 최남섭; 정유석; 이지현; 김도현
Original assignee: 명지대학교 산학협력단
Priority date: 2012-03-12
Filing date: 2012-05-10
Publication date: 2013-09-19
Also published as: KR101333409B1; KR20130103863A

Abstract

A bidirectional high-frequency resonator and a bidirectional transformer using the same are disclosed. The disclosed bidirectional transformer comprises: a bidirectional high-frequency transformer for converting between a first high-voltage AC which is inputted and outputted through a first input and output port and a rectified voltage which is inputted and outputted through a second input and output port; a bidirectional AC/DC converter for converting between the rectified voltage which is inputted and outputted through the first input and output port and a DC voltage which is inputted and outputted through the second input and output port; and a bidirectional DC/AC converter for converting between the DC voltage which is inputted and outputted through the first input and output port and a second low-voltage AC which is inputted and outputted through the second input and output port, wherein the bidirectional high-frequency transformer includes N(an integer of 2 or higher) resonant converters which are connected in serial, and each of the N resonant converter includes: a transformer; a first resonance circuit connected to a core at one side of the transformer and having a plurality of switching elements which are connected in serial; and a second resonance circuit connected to a core at the other side of the transformer and having a plurality of switching elements which are connected in serial.

Description

Bidirectional high frequency resonator and bidirectional transformer using the same

Embodiments of the present invention relate to a bidirectional high frequency resonator and a bidirectional transformer using the same, and more particularly, to a high frequency resonator using a semiconductor device capable of easily expanding to high voltage and operating in both directions, and a transformer including the same.

Digital loads, which are rapidly increasing in use, require not only operation at various voltage levels but also various electric qualities, and researches on multifunctional transformers to meet these demands are being actively conducted.

1 is a circuit diagram showing the overall configuration of a conventional multifunctional transformer.

Referring to FIG. 1, a primary side performing high voltage switching includes a circuit of a series switch structure corresponding to a high voltage, and a secondary side includes a circuit including a general inverter.

However, the conventional multifunction transformer according to FIG. 1 has a problem in that it is difficult to balance the switch breakdown voltage when three or more series operations are required due to an increase in input voltage due to high operation of two switches.

In addition, the conventional multifunction transformer according to FIG. 1 has a structure in which power transmission in both directions is impossible, and thus there is a problem in that it is difficult to be applied to a system in which bidirectional power transmission is required such as a smart grid.

In order to solve the problems of the prior art as described above, the present invention proposes a high frequency resonator using a semiconductor device that can be easily extended to high voltage and can operate in both directions, and a transformer including the same.

Other objects of the present invention may be derived by those skilled in the art through the following examples.

According to a preferred embodiment of the present invention to achieve the above object, a bidirectional high frequency for converting between the first AC voltage of the high voltage input and output through the first input and output terminal and the rectified voltage input and output through the second input and output terminal Transformer unit; A bidirectional AC / DC converter for converting between the rectified voltage inputted and outputted through a first input / output terminal and a DC voltage inputted and outputted through a second input / output terminal; And a bidirectional DC / AC converter configured to convert between the DC voltage input / output through the first input / output terminal and the second AC voltage of low voltage input / output through the second input / output terminal, wherein the bidirectional high frequency transformer is connected in series. And N (integer of 2 or more) resonant converters, each of the N resonant converters comprising: a transformer; A first resonant circuit connected to one core of the transformer and including a plurality of switching elements connected in series; And a second resonant circuit connected to the other core of the transformer and including a plurality of switching elements connected in series.

In addition, according to another embodiment of the present invention, including N (integer or greater) two resonant converters connected in series, each of the N resonant converter is a transformer; A first circuit connected to one core of the transformer and including a plurality of switching elements connected in series; And a second circuit connected to the other core of the transformer and including a plurality of switching elements connected in series, the plurality of switching elements included in the first circuit and the plurality of switching elements included in the second circuit. Each of the transistors to provide a current path from one end to the other; And a diode for providing a current path from the other end to the one end.

The high frequency resonator and the transformer according to the present invention have the advantage of being easy to expand to high pressure and operating in both directions.

2 is a block diagram showing a schematic configuration of a bidirectional transformer according to an embodiment of the present invention.

3 is a circuit diagram showing a detailed configuration of a bidirectional transformer 200 according to an embodiment of the present invention.

4 and 5 are diagrams showing an example of a form of a control signal applied to the control electrodes of the transistors included in the switching elements of the bidirectional high frequency transformer configured as described above.

6 and 7 are diagrams illustrating current flow in each resonant converter when the first AC voltage has a positive value and the bidirectional high frequency transformer is operated in the forward direction.

8 and 9 are views illustrating current flow in each resonant converter when the first AC voltage has a positive value and the bidirectional high frequency transformer is operated in the reverse direction.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the drawings, similar reference numerals are used for similar elements.

And when a component is said to be "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but another component may be present in the middle. It should be understood that. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2, the bidirectional transformer 200 according to an embodiment of the present invention includes a bidirectional high frequency transformer 210, a bidirectional AC / DC converter 220, and a bidirectional DC / AC converter 230. Hereinafter, the function of each component will be described in detail.

The bidirectional high frequency transformer 210 converts the first AC voltage having a high voltage into a rectified voltage or converts the rectified voltage into a first AC voltage. That is, the bidirectional high frequency transformer 210 converts the first AC voltage of the high voltage input through the first input / output terminal into a low voltage rectified voltage and outputs it to the second input / output terminal or the low voltage rectification input through the second input / output terminal. The voltage is changed to a high voltage first AC voltage and output to the first input / output terminal. The bidirectional high frequency transformer 210 may operate at a fixed duty as described in detail below.

The bidirectional AC / DC converter 220 converts the rectified voltage into a DC voltage or changes the DC voltage into a rectified voltage. That is, the first input / output terminal of the bidirectional AC / DC converter 220 is connected to the second input / output terminal of the bidirectional high frequency transformer 210, and the bidirectional AC / DC converter 220 is rectified through the first input / output terminal. The voltage is converted into a DC voltage and output to the second input / output terminal, or the DC voltage input through the second input / output terminal is changed to a rectified voltage and output to the first input / output terminal. Through this, the bidirectional AC / DC converter 220 serves to improve the power factor of the bidirectional transformer 200.

The bidirectional DC / AC converter 230 changes the DC voltage to the second AC voltage of the low voltage or the second AC voltage of the low voltage to the DC voltage. That is, the first input / output terminal of the bidirectional DC / AC converter 230 is connected to the second input / output terminal of the bidirectional AC / DC converter 220, and the bidirectional DC / AC converter 230 is input through the first input / output terminal. The DC voltage is changed to a low voltage second AC voltage and output to the second input / output terminal, or the second AC voltage of low voltage input through the second input / output terminal is changed to a DC voltage and output to the first input / output terminal. The bidirectional DC / AC converter 230 may operate with a variable duty and control a load.

Hereinafter, the detailed configuration and operation of the bidirectional transformer 200 will be described in more detail with reference to FIGS. 3 to 9.

3 is a circuit diagram showing a detailed configuration of a bidirectional transformer 200 according to an embodiment of the present invention. The function of each component will be described in detail with reference to FIG. 3 below.

First, the bidirectional high frequency transformer 210 may include N resonant converters 211 (which are integers of 2 or more) connected in series. The resonant converter 211 is connected to the transformer 212, the coil of one side of the transformer 212, the first circuit 213 including a plurality of switching elements connected in series and the other coil of the transformer 212 and connected in series The second circuit 214 includes a plurality of switching elements.

According to one embodiment of the present invention, each of the plurality of switching elements included in the first circuit 213 and the plurality of switching elements included in the second circuit 214 includes a transistor and a diode as shown in FIG. 3. can do. Hereinafter, for convenience of description, a point where the first conducting electrode of the transistor such as the collector to the drain and the output terminal of the diode are connected is referred to as "one end of the switching element", and the second conducting electrode of the transistor such as the emitter to the source and The point where the input terminal of the diode is connected will be referred to as the "other end of the switching element". As an example, the transistor may be an Insulated Gate Bi-Polar Transistor (IGBT).

Such a transistor provides a current path from one end of the switching element to the other end, and a diode provides a current path from the other end of the switching element to one end. That is, when the transistor is turned on (when a voltage higher than the threshold voltage is applied to the base or gate as the control electrode of the transistor), the switching element provides a current path from one end to the other end through the transistor and switches when the transistor is turned off. The device provides a current path from the other end to the end through the diode.

In addition, according to an embodiment of the present invention, as shown in FIG. 3, the first circuit 213 includes four switching elements M _1x , M _2x , M _3x , and M _4x connected in series, and a second circuit. The circuit 214 may include two switching elements M _5x , M _6x connected in series.

First, the connection relationship of each element in the first circuit 213 will be described below.

One end of the first switching element M _1x is connected to the other end of one coil of the transformer 212, and the other end of the first switching element M _{1x is} connected to the other end of the second switching element M _2x . One end of the two switching elements M _2x is connected to one end of one coil of the transformer 212. One end of the third switching element M _3x is connected to one end of one coil of the transformer 212, and the other end of the third switching element M _{3x is} connected to the other end of the fourth switching element M _4x . One end of the fourth switching element M _4x is connected to the other end of one coil of the transformer 212.

Here, one end of the first switching element (M _1x ) is connected to the other end of one side coil of the transformer 212 through the first capacitor (C ₁ ), one end of the fourth switching element (M _4x ) is the second capacitor ( C connection ₂₎ the other end of one side coil of the transformer (212) end and through and, a is applied to the first capacitor (C ₁₎ and second capacitor (C ₂₎ is the voltage (V _a) distribution of the first AC voltage.

Next, the connection relationship of the elements in the second circuit 214 will be described below.

One end of the fifth switching device M _5x is connected to the other end of the other coil of the transformer 212, and the other end thereof is connected to the one end of the other coil of the transformer 212. In addition, one end of the sixth switching element M _6x is connected to one end of the other coil of the transformer 212, and the other end thereof is connected to the other end of the other coil of the transformer 212.

Here, one end of the fifth switching element (M _5x ) is connected to the other end of the other coil of the transformer 212 through the third capacitor (C ₃ ), the other end of the fifth switching element (M _5x ) is the first inductor ( L ₁ ) is connected to one end of the other coil of the transformer 212. Then, the sixth switching element the first inductor is connected to one end of the other coil of the transformer 212 through an (L _1), a sixth switching element the other end of the (M _6x) has a fourth capacitor (C ₃ of (M _6x) It is connected to the other end of the coil of the other side of the transformer (212) through.

In addition, the resonant frequency of each of the N resonant converters 211 is the size of the third capacitor (C ₃ ) and the fourth capacitor (C ₃ ) and the size of the first inductor (L ₁ ) (that is, the third capacitor (C ₃₎ ) And the fourth capacitor C ₃ and the size of the resonant tank formed by the first inductor L ₁ ).

4 is a control signal applied to control electrodes of transistors included in switching elements M _1x , M _2x , M _3x , M _4x , M _5x , and M _{6x of} the bidirectional high frequency transformer 210 configured as described above. It is a figure which shows an example of the form of a.

Referring to FIG. 4, when the first AC voltage has a positive value (that is, when V _a has a positive value), the first switching element M _1x , the third switching element M _3x , and the fifth The switching element M _5x and the sixth switching element M _6x operate at a fixed frequency fixed ratio (ie, fixed duty), and the second switching element M _2x and the fourth switching element M _4x are always Is on.

That is, when the first AC voltage has a positive value, the transistor included in the first switching element M _1x and the transistor included in the fifth switching element M _5x are periodically turned on / off at the same time, and the third The transistor included in the switching element M _3x and the transistor included in the sixth switching element M _6x are periodically turned on and off simultaneously, and the transistor and the fourth switching element included in the second switching element M _2x ( The transistor included in M _4x ) is always on.

In addition, when the transistor included in the first switching element M _1x and the transistor included in the fifth switching element M _5x are turned on, the transistor included in the third switching element M _3x and the sixth switching element ( The time that the transistors included in M _6x ) are turned on do not overlap each other.

In more detail, the transistors included in the first switching element M _1x to the sixth switching element M _6x may be turned on / off as shown in FIG. 5A. Hereinafter, for convenience of description, the time interval in which the first switching device M _1x is turned on is “MODE 1”, and the third switching device M _3x is turned on after the first switching device M _1x is turned off. in the time interval until the "MODE 2", the third switching device (M _3x) is the time interval that is on a "MODE 3", the third switching device (M _3x) after it is turned off the first switching element (M The time interval before _1x ) is turned on will be referred to as "MODE 4".

4, when the first AC voltage has a negative value (that is, when V _a has a negative value), the second switching element M _2x , the fourth switching element M _4x , The fifth switching element M _5x and the sixth switching element M _6x operate at a fixed frequency fixed ratio, and the first switching element M _1x and the third switching element M _3x are always on.

That is, when the first AC voltage has a negative value, the transistor included in the second switching element M _2x and the transistor included in the sixth switching element M _6x are periodically turned on and off simultaneously, and the fourth switching elements (M _4x) transistor and a fourth switching element (M _4x) the transistor is at the same time is periodically turned on / off, a transistor and the third switching device included in the first switching element (M _1x) included in included in the ( The transistor included in M _3x ) is always on.

In addition, when the transistor included in the second switching element M _2x and the transistor included in the sixth switching element M _6x are turned on, the transistor included in the fourth switching element M _4x and the fifth switching element ( The time that the transistors included in M _4x ) are turned on do not overlap each other.

In more detail, the transistors included in the first switching element M _1x to the sixth switching element M _6x may be turned on / off as shown in FIG. 5B. Hereinafter, for convenience of description, the time interval in which the second switching device M _2x is turned on is “MODE 5”, and the fourth switching device M _4x is turned on after the second switching device M _2x is turned off. in the time interval until the "MODE 6", the fourth switching device (M _4x) is a time interval that is on a "MODE 7", the fourth switching device (M _4x) after it is off the second switching device (M The time interval until _2x ) is turned on will be referred to as "MODE 8".

6 to 9 will be described in more detail the operation of the bidirectional high frequency transformer 210.

6 and 7 illustrate a current flow in each resonant converter 211 when the bidirectional high frequency transformer 210 operates in a forward direction while the first AC voltage has a positive value.

First, in the case of "MODE 1", since the third switching element M _3x and the sixth switching element M _6x are turned off, the resonant converter 211 has a current flow as shown in FIG. As a result, the first inductor L ₁ and the third capacitor C ₃ operate as the resonant tank. Next, in the case of "MODE 2", since the first switching element M _1x , the third switching element M _3x , the fifth switching element M _5x and the sixth switching element M _6x are turned off, the resonant converter At 211, a current flow as shown in FIG. 6B is formed. Such operation in the "MODE 2" is a first switching element (M _1x) that when the switching operation, the third switching device (M _3x) Because there voltage is jammed, a first switching element (M _1x) and the third During the period in which the switching element M _3x is turned off, the current accumulated in the first inductor L ₁ , which is the leakage inductor, is released to remove the voltage applied to the third switching element M _3x .

Subsequently, in the case of "MODE 3", since the first switching element M _1x and the fifth switching element M _5x are turned off, the resonant converter 211 has a current flow as shown in FIG. 7A. As a result, the first inductor L ₁ and the fourth capacitor C ₄ operate as the resonant tank. Next, in the case of "MODE 4", since the first switching device M _1x , the third switching device M _3x , the fifth switching device M _5x , and the sixth switching device M _6x are turned off, Resonant converter 211 is formed with a current flow as shown in (b) of FIG. This operation in "MODE 4" is also performed on the same principle as the operation of "MODE 2" described above.

8 and 9 illustrate a flow of current in each resonant converter 211 when the bidirectional high frequency transformer 210 operates in a reverse direction while the first AC voltage has a positive value.

8 and 9, in “MODE 1” in which the third switching element M _3x and the sixth switching element M _6x are turned off, a current flow as shown in FIG. 8A is formed to form a first inductor. L ₁ and the third capacitor C ₃ operate as the resonant tank, and after “MODE 1”, the first switching element M _1x , the third switching element M _3x , and the fifth switching element M _5x And “MODE 2” in which the sixth switching element M _6x is turned off, a current flow as shown in FIG. 8B is formed. Further, in "MODE 3" in which the first switching element M _1x and the fifth switching element M _5x are turned off, a current flow as shown in FIG. 9A is formed to form the first inductor L ₁ . And the third capacitor C ₃ operates as a resonant tank, and after “MODE 3” the first switching element M _1x , the third switching element M _3x , the fifth switching element M _5x and the sixth switching In " MODE 4 " in which the element M _6x is turned off, a current flow as shown in Fig. 9B is formed.

On the other hand, when the first AC voltage has a negative value and the bidirectional high frequency transformer 210 operates in the forward or reverse direction, the current flow in the resonant converter 211 can be easily obtained from the contents of FIGS. 6 to 9. Since it can be inferred, description thereof will be omitted.

As described above, the first circuit 213 including four switching elements M _1x , M _2x , M _3x , and M _4x connected in series is different from the conventional technology using four switching elements connected in a full bridge form. And a second circuit 214 including two switching elements M _5x and M _6x connected in series to control the high-frequency resonator in both directions by using a control signal as shown in FIG. 4.

In this case, since the first switching element M _1x / the third switching element M _{3x is} connected to the second switching element M _2x / the fourth switching element M _4x in the opposite direction, the first AC voltage is increased. The same operation is performed in both a positive value and a negative value case.

That is, when the first AC voltage has a positive value, the first switching element M _1x and the third switching element M _3x perform complementary operations, and when the first AC voltage has a negative value, The second switching element M _2x and the fourth switching element M _4x perform a complementary operation, and the first switching element M _1x and the third switching element M _3x are always kept in an on state so as to be described later. The AC / DC converter 220 is powered to rectify the direct current. In the reverse operation, the roles of the first switching element M _1x to the fourth switching element M _4x , the fifth switching element M _5x , and the sixth switching element M _6x are changed. (M _1x ) to fourth switching element M _4x are used as rectifiers.

In addition, when the resonant frequency of the bidirectional high frequency transformer 210 (that is, the resonant converter 211) operates at a fixed duty, and the resonant frequency determined by the resonant tank coincides with the switching frequency described with reference to FIG. The gain of the converter is determined by the turns ratio (n: 1) of the transformer, regardless of the load. In this case, when a high frequency of about 50 KHz is used as the switching frequency, the size of the bidirectional high frequency transformer 210 may be reduced. In addition, there is an advantage that the flow of power is formed in both directions even without a separate control according to the input and output conditions.

Next, the bidirectional AC / DC converter 220 includes a seventh switching element M ₇ and an eighth switching element M ₈ having one end connected to the other end of the seventh switching element M ₇ . In this case, the seventh switching element M ₇ and the eighth switching element M ₈ may include a transistor 221 for providing a current path from one end to the other end; And a diode 222 for providing a current path from the other end to one end.

The bidirectional AC / DC converter 220 includes a fifth capacitor C ₅ connected to a first input / output terminal through which a rectified voltage is input / output; A second inductor L ₂ having one end connected to one end of the fifth capacitor C ₅ and the other end connected to the other end of the seventh switching element M ₇ and one end of the eighth switching element M ₈ ; And a fourth capacitor C ₄ , one end of which is connected to one end M ₇ of the seventh switching element and the other end of which is connected to the other end of the eighth switching element M ₈ .

The bidirectional AC / DC converter 220 configured as described above performs a function of improving power factor. That is, the bidirectional AC / DC converter 220 controls the current I _L2 flowing in the second inductor L ₂ to follow the rectified voltage V _link applied to the fifth capacitor C ₅ , and simultaneously 6 controls the DC voltage (V _dc ) applied to the capacitor (C ₆ ).

In addition, the bidirectional AC / DC converter 220 determines the directionality of the bidirectional transformer 200. That is, when the DC voltage V _dc is output from the sixth capacitor C ₆ , the current I _L2 flowing in the second inductor L ₂ becomes positive, and the bidirectional transformer 200 operates in the reverse direction. When the DC voltage V _dc is applied to the six capacitors C ₆ , the current I _L2 flowing in the second inductor L ₂ becomes negative, and the bidirectional transformer 200 operates in the forward direction.

Lastly, the bidirectional DC / AC converter 230 may include a ninth switching element M ₉ , a tenth switching element M ₁₀ , an eleventh switching element M ₁₁ , and a twelfth switching element connected in a full bridge form. M ₁₂ ), the third inductor L ₃ , and the seventh capacitor C ₇ . The bidirectional DC / AC converter 230 controls the output voltage (V _{o, ac} ) by using a DC voltage (V _dc ).

In short, the bidirectional transformer 200 according to an embodiment of the present invention has a three-stage structure of a bidirectional high frequency resonator (rectifier) using a high frequency resonant LLC circuit, a power factor improving stage for improving reactive power, and an inverter stage for generating an output voltage. In addition, it has an easy structure to perform bidirectional operation according to the input / output conditions and to form a breakdown voltage balance of the switching element. In addition, when three bidirectional transformers 200 are used, the three-phase system can be expanded.

In the present invention as described above has been described by the specific embodiments, such as specific components and limited embodiments and drawings, but this is provided to help the overall understanding of the present invention, the present invention is not limited to the above embodiments, Various modifications and variations can be made by those skilled in the art to which the present invention pertains. Therefore, the spirit of the present invention should not be limited to the described embodiments, and all the things that are equivalent to or equivalent to the claims as well as the following claims will belong to the scope of the present invention. .

Claims

A bidirectional high frequency transformer for converting between a first AC voltage having a high voltage input / output through the first input / output terminal and a rectified voltage input / output through the second input / output terminal;

A bidirectional AC / DC converter for converting between the rectified voltage inputted and outputted through a first input / output terminal and a DC voltage inputted and outputted through a second input / output terminal; And

And a bidirectional DC / AC converter for converting between the DC voltage inputted and outputted through the first input / output terminal and the second AC voltage of low voltage inputted and outputted through the second input / output terminal,

The bidirectional high frequency transformer unit includes N resonance converters connected in series, wherein N is an integer of 2 or more;

Each of the N resonant converters includes a transformer; A first resonant circuit connected to one core of the transformer and including a plurality of switching elements connected in series; And a second resonant circuit connected to the other core of the transformer and including a plurality of switching elements connected in series.
The method of claim 1,

Each of the plurality of switching elements included in the first circuit and the plurality of switching elements included in the second circuit may include a transistor for providing a current path from one end to the other end; And a diode for providing a current path from said other end to said one end.
The method of claim 2,

The plurality of switching elements included in the first circuit may include a first switching element having one end connected to the other end of one coil of the transformer; A second switching element having one end connected to one end of one coil of the transformer and the other end connected to the other end of the first switching element; A third switching element having one end connected to one end of one coil of the transformer; And a fourth switching element having one end connected to the other end of the coil of one side of the transformer and the other end connected to the other end of the third switching element.
The method of claim 3,

One end of the first switching element is connected to the other end of the coil of one side of the transformer through a first capacitor, and one end of the fourth switching element is connected to the other end of the coil of one side of the transformer through a second capacitor.

And a divided voltage of the first AC voltage is applied to the first capacitor and the second capacitor.
The method of claim 3,

The plurality of switching elements included in the second circuit may include a fifth switching element having one end connected to the other end of the other coil of the transformer and the other end connected to the one end of the other coil of the transformer; And a sixth switching element having one end connected to one end of the other coil of the transformer and the other end connected to the other end of the other coil of the transformer.
The method of claim 5,

One end of the fifth switching element is connected to the other end of the other coil of the transformer through a third capacitor, and the other end of the fifth switching element is connected to one end of the other coil of the transformer through the first inductor. One end of the six switching element is connected to the one end of the other coil of the transformer through the first inductor, the other end of the sixth switching element is connected to the other end of the other coil of the transformer through the fourth capacitor,

The resonance frequency of the resonant converter is determined by the size of the third capacitor and the fourth capacitor and the size of the first inductor.
The method of claim 5,

When the first AC voltage has a positive value,

The transistor included in the first switching element and the transistor included in the fifth switching element are periodically turned on and off simultaneously, and the transistor included in the third switching element and the transistor included in the sixth switching element are simultaneously periodically On and off, the transistor included in the second switching device and the transistor included in the fourth switching device are always on,

The time when the transistor included in the first switching element and the transistor included in the fifth switching element are turned on and the time when the transistor included in the third switching element and the transistor included in the sixth switching element are not overlapped with each other. Bi-directional transformer, characterized in that not.
The method of claim 5,

When the first AC voltage has a negative value,

The transistor included in the second switching element and the transistor included in the sixth switching element are periodically turned on and off simultaneously, and the transistor included in the fourth switching element and the transistor included in the fifth switching element are simultaneously periodically On and off, the transistor included in the first switching device and the transistor included in the third switching device are always on,

The time when the transistor included in the second switching element and the transistor included in the sixth switching element are turned on and the time when the transistor included in the fourth switching element and the transistor included in the fifth switching element are turned on do not overlap each other. Bi-directional transformer, characterized in that not.
The method of claim 1,

The bidirectional AC / DC converter includes a seventh switching element; And an eighth switching device, one end of which is connected to the other end of the seventh switching device.

The seventh and eighth switching elements may include a transistor for providing a current path from one end to the other end; And a diode for providing a current path from said other end to said one end.
The method of claim 9,

The bidirectional AC / DC converter may include a fifth capacitor connected to a first input / output terminal through which the rectified voltage is input / output; A second inductor having one end connected to one end of the fifth capacitor and the other end connected to the other end of the seventh switching element and one end of the eighth switching element; And a sixth capacitor having one end connected to one end of the seventh switching element and the other end connected to the other end of the eighth switching element.
The method of claim 1,

The bidirectional DC / AC converter includes a ninth switching element, a tenth switching element, an eleventh switching element, and a twelfth switching element connected in a bridge form.
Including N resonant converters (integer or greater than 2) connected in series,

Each of the N resonant converters includes a transformer; A first circuit connected to one core of the transformer and including a plurality of switching elements connected in series; And a second circuit connected to the other core of the transformer and including a plurality of switching elements connected in series.

Each of the plurality of switching elements included in the first circuit and the plurality of switching elements included in the second circuit may include a transistor for providing a current path from one end to the other end; And a diode for providing a current path from said other end to said one end.
The method of claim 12,

The plurality of switching elements included in the first circuit may include a first switching element having one end connected to the other end of one coil of the transformer; A second switching element having one end connected to one end of one coil of the transformer and the other end connected to the other end of the first switching element; A third switching element having one end connected to one end of one coil of the transformer; And a fourth switching device, one end of which is connected to the other end of the coil of one side of the transformer and the other end of which is connected to the other end of the third switching element.
The method of claim 13,

One end of the first switching element is connected to the other end of the coil of one side of the transformer through a first capacitor, and one end of the fourth switching element is connected to the other end of the coil of one side of the transformer through a second capacitor.

And a divided voltage of the first AC voltage is applied to the first capacitor and the second capacitor.
The method of claim 13,

The plurality of switching elements included in the second circuit may include a fifth switching element having one end connected to the other end of the other coil of the transformer and the other end connected to the one end of the other coil of the transformer; And a sixth switching element having one end connected to one end of the other coil of the transformer and the other end connected to the other end of the other coil of the transformer.
The method of claim 15,

One end of the fifth switching element is connected to the other end of the other coil of the transformer through a third capacitor, and the other end of the fifth switching element is connected to one end of the other coil of the transformer through the first inductor. One end of the six switching element is connected to the one end of the other coil of the transformer through the first inductor, the other end of the sixth switching element is connected to the other end of the other coil of the transformer through the fourth capacitor,

The resonance frequency of the resonant converter is determined by the size of the third capacitor and the fourth capacitor and the size of the first inductor.
The method of claim 15,

When the first AC voltage has a positive value,

The transistor included in the first switching element and the transistor included in the fifth switching element are periodically turned on and off simultaneously, and the transistor included in the third switching element and the transistor included in the sixth switching element are simultaneously periodically On and off, the transistor included in the second switching device and the transistor included in the fourth switching device are always on,

The time when the transistor included in the first switching element and the transistor included in the fifth switching element are turned on and the time when the transistor included in the third switching element and the transistor included in the sixth switching element are not overlapped with each other. Bidirectional high frequency resonator, characterized in that not.
The method of claim 15,

When the first AC voltage has a negative value,

The transistor included in the second switching element and the transistor included in the sixth switching element are periodically turned on and off simultaneously, and the transistor included in the fourth switching element and the transistor included in the fifth switching element are simultaneously periodically On and off, the transistor included in the first switching device and the transistor included in the third switching device are always on,

The time when the transistor included in the second switching element and the transistor included in the sixth switching element are turned on and the time when the transistor included in the fourth switching element and the transistor included in the fifth switching element are turned on do not overlap each other. 2 bidirectional high frequency resonator.