KR20210096446A - A bidirectional resonant dc-dc converter - Google Patents

Abstract

Provided is a bidirectional resonant DC-DC converter that proposes main circuits, which are easier to manufacture. According to the present invention, the bidirectional resonant DC-DC converter can facilitate gain control by respectively operating with the unique gain characteristics of an LLC resonance converter during forward and reverse power transfer operation due to the operation characteristics according to a transformer winding polarity (main winding and auxiliary winding applied for gain control) and a resonant capacitor common connection line of two resonant circuits while not having the mutually coupled DLLC resonance characteristics even if operating by applying a resonance capacitor to a primary circuit unit and a secondary circuit unit, and operate with a wide input/output voltage control range.

Description

Bidirectional Resonant DC-DC Converter {A BIDIRECTIONAL RESONANT DC-DC CONVERTER}

The present invention relates to a resonant DC-DC converter capable of bidirectional power transmission in two isolated power supply systems.

Recently, a bidirectional direct current (DC-DC) converter power converter is required in application fields such as microgrids, energy storage systems (ESS), and electric vehicle charging/discharging systems.

A DC-DC converter capable of bidirectional power transfer using an isolated high-frequency transformer has been developed, including a method consisting of a voltage source converter and a DC-DC converter capable of bidirectional power transfer in which a voltage source converter and a current source converter are combined. However, basically, these power conversion devices have a large disadvantage in power conversion loss due to switching loss due to hard switching.

Recently, to reduce size, switching loss, and EMI (Electro-Magnetic Interference), two-way DC-DC converters incorporating a resonant converter capable of Zero Voltage Switching (ZVS) are being applied and reviewed.

1 shows an embodiment of a conventional bidirectional resonant converter. As shown in Fig. 1, resonant capacitors (Cr1, Cr2 (or CB1)) are applied to the primary and secondary sides of the resonant converter capable of bidirectional power transfer. Accordingly, the LLC resonance characteristic as shown in FIG. 2A, the CLLC resonance gain characteristic in which the CCL operation characteristic and the LLC resonance characteristic are mixed as shown in FIG. 2B, and the series resonant converter (SRC) resonance gain characteristic as shown in FIG. 2C appear. In particular, when the resonant capacitors Cr1 and Cr2 are applied to the primary and secondary sides, the gain at a frequency range lower than the resonance frequency fr and heavy load due to mutual coupling of the resonant capacitors Cr1 and Cr2 during bidirectional power transfer operation Since the slope has a slope having a value lower than the gain at the resonance frequency point fr, it has a resonance gain characteristic different from the gain characteristic of the existing LLC resonant converter, which makes it difficult to transmit power in both directions.

In order to solve the problems of the prior art, the present invention provides a bidirectional resonant direct current (DC-DC) converter capable of gain control by a variable switching frequency during operation of a main circuit for power transmission in forward and reverse directions. aims to provide

Another object of the present invention is to provide a bidirectional resonant DC-DC converter that proposes main circuits that are easier to manufacture.

Another object of the present invention is to provide a DC-DC converter capable of bidirectional power transfer having high gain characteristics and high efficiency characteristics by having gain characteristics unique to the LLC resonant converter in both forward and reverse power transfer modes.

Another object of the present invention is to provide a bidirectional resonant DC-DC converter capable of easily designing gain control in forward and reverse power transfer modes.

Another object of the present invention is to provide a bidirectional resonant DC-DC converter capable of easily increasing capacity using the main circuits proposed by the present invention.

In order to achieve the above object, a bidirectional resonant DC-DC converter according to an embodiment (first type) of the present invention includes a primary circuit part connected to a first voltage source and a secondary circuit part connected to a second voltage source. A bidirectional resonant DC-DC converter comprising: a primary side switch module including a plurality of switching elements; a primary side voltage divider capacitor unit; and the secondary-side circuit unit includes a secondary-side switch module including a plurality of switching elements, a secondary-side voltage dividing capacitor unit, a secondary winding of each of the first transformer and the second transformer, a secondary-side first resonance reactance element, and a secondary-side second and two resonant reactance elements, wherein the primary side first resonant circuit unit includes a first transformer primary side main winding, a primary side first auxiliary winding unit, and a primary side first resonant reactance element connected in series, and the primary side second The resonance circuit unit includes a second transformer primary side main winding, a primary side secondary winding unit and a primary side second resonant reactance element connected in series, the primary side first resonant reactance element, the primary side second resonant reactance element, The secondary-side first resonant reactance element and the secondary-side second resonant reactance element include a resonant capacitor and a resonant inductor, and the first transformer primary main winding and the primary primary auxiliary winding of the primary-side first resonant circuit part A node to which an additionally connected node is connected to a node to which the second primary-side main winding of the transformer of the primary-side and the second auxiliary winding of the primary-side is connected is characterized in that it is connected through a first common connection line.

Here, the primary-side first auxiliary winding unit includes a first auxiliary winding on the primary side of a first transformer and a first auxiliary winding on the primary side of the second transformer, and the second auxiliary winding on the primary side includes a second auxiliary winding on the primary side of the first transformer. and a second auxiliary winding on the primary side of a second transformer, wherein the first main winding on the primary side of the first transformer and the first auxiliary winding on the primary side are wound to have the same polarity, and the secondary main winding on the primary side of the second transformer and the secondary winding on the primary side are wound to have the same polarity. The two auxiliary windings may be wound to have the same polarity, and one of the first transformer secondary winding and the second transformer secondary winding may be wound to have different polarities.

Further, in the forward power transfer mode, a current flows through the primary-side first resonant reactance element and the primary-side second resonant reactance element, and a current flows through the secondary-side first resonant reactance element and the secondary-side second resonant reactance element. does not flow, and in the reverse power transfer mode, current flows in the secondary-side first resonant reactance element and the secondary-side second resonant reactance element, and the primary-side first resonant reactance element, the primary-side first auxiliary winding unit and the It is characterized in that no current flows between the primary-side second resonant reactance element and the primary-side second auxiliary winding portion.

In addition, the primary side switch module includes a first bridge-arm to which 1-1 and 1-2 switching elements are connected in series and a second bridge to which 1-3 and 1-4 switching elements are connected in series. - an arm, wherein the primary-side voltage-dividing capacitor unit includes a primary-side first voltage-dividing capacitor and a primary-side second voltage-dividing capacitor connected in series, the first voltage source, the first bridge-arm, and the second bridge-arm connected in parallel with, one end of the primary-side first resonance circuit unit is connected to a node to which the 1-1 and 1-2 switching elements are connected, and the other end of the primary-side first voltage dividing capacitor and the primary-side second switching element is connected to It is connected to the primary side central node to which the second voltage dividing capacitor is connected, and one end of the primary side second resonance circuit part is connected to the node to which the 1-3 and 1-4 switching elements are connected, and the other end is the primary side central node. can be connected to

In addition, the secondary-side switch module includes a third bridge-arm to which 2-1 and 2-2 switching elements are connected in series, and a fourth bridge to which second-3 and 2-4 switching elements are connected in series. - an arm, wherein the secondary-side voltage-dividing capacitor unit includes a secondary-side first voltage-dividing capacitor and a secondary-side second voltage-dividing capacitor connected in series, the second voltage source, the third bridge-arm, and the fourth bridge-arm One end of the secondary winding of the first transformer is connected to a node connected in parallel to and to which the 2-1 and 2-2 switching elements are connected, and the 2-3 and 2-4 switching elements are connected One end of the secondary winding of the second transformer is connected to a node to One end of the secondary-side second resonant reactance element may be connected, and the other end of the secondary-side first resonant reactance element and the other end of the secondary-side second resonant reactance element are connected through a second common connection line.

In another embodiment (type 4-1) of the bidirectional resonant DC-DC converter of the present invention, the secondary-side switch module includes a third bridge to which 2-1 and 2-2 switching elements are connected in series. an arm and a fourth bridge-arm to which second-third and second-fourth switching elements are connected in series, wherein the secondary-side voltage divider capacitor includes a secondary-side first voltage divider capacitor and a secondary-side second voltage divider capacitor and one end of the secondary-side first resonant reactance and one end of the secondary-side second resonant reactance meet and connect at a secondary-side central node, and the other end is connected to the secondary-side first voltage dividing capacitor and the secondary-side second voltage dividing capacitor, respectively. connected, and the other end of the secondary-side first resonant reactance element and the other end of the secondary-side second resonant reactance element are connected through a second common connection line. One end of the secondary winding of the first transformer is connected to a node to which the 2-1 and 2-2 switching elements are connected, and the second to a node to which the 2-3 and 2-4 switching elements are connected. One end of the secondary winding of the transformer may be connected, and the other end of the secondary winding of the first transformer and the other end of the secondary winding of the second transformer may meet and be connected at the secondary central node.

A bidirectional resonant DC-DC converter according to another embodiment (second type) of the present invention is a bidirectional resonant DC-DC including a primary circuit unit connected to a first voltage source and a secondary circuit unit connected to a second voltage source. A converter, wherein the primary-side circuit part includes a primary-side switch module including a plurality of switching elements, a primary-side first resonance circuit part and a primary-side second resonance circuit part, and the secondary-side circuit part includes a plurality of switching elements a secondary-side switch module, a secondary-side voltage dividing capacitor unit, a secondary winding of each of a first transformer and a second transformer, a secondary-side first resonant reactance element and a secondary-side second resonant reactance element, wherein the primary-side first resonant circuit A first transformer primary main winding, a primary primary auxiliary winding unit, and a primary side first resonant reactance element are connected in series, and the primary side second resonant circuit unit is a second transformer primary main winding and a primary side first Two auxiliary winding units and a second primary-side resonant reactance element are connected in series, and the primary-side first resonant reactance element, the primary-side second resonant reactance element, the secondary-side first resonant reactance element, and the secondary-side second resonant reactance element The resonant reactance element includes a resonant capacitor and a resonant inductor, and a node connected to the first transformer primary side main winding of the primary side first resonant circuit unit and the primary side first auxiliary winding unit and the second resonant circuit unit of the primary side Second, a node connected to the primary side main winding of the transformer and the secondary secondary winding unit on the primary side is connected through a first common connection line.

Here, the primary-side first auxiliary winding unit includes a first auxiliary winding on the primary side of a first transformer and a first auxiliary winding on the primary side of the second transformer, and the second auxiliary winding on the primary side includes a second auxiliary winding on the primary side of the first transformer. and a second auxiliary winding on the primary side of a second transformer, wherein the first main winding on the primary side of the first transformer and the first auxiliary winding on the primary side are wound to have the same polarity, and the secondary main winding on the primary side of the second transformer and the secondary winding on the primary side are wound to have the same polarity. The two auxiliary windings may be wound to have the same polarity, and one of the first transformer secondary winding and the second transformer secondary winding may be wound to have different polarities.

Further, in the forward power transfer mode, a current flows through the primary-side first resonant reactance element and the primary-side second resonant reactance element, and a current flows through the secondary-side first resonant reactance element and the secondary-side second resonant reactance element. does not flow, and in the reverse power transfer mode, current flows in the secondary-side first resonant reactance element and the secondary-side second resonant reactance element, and the primary-side first resonant reactance element, the primary-side first auxiliary winding unit and the It is characterized in that no current flows between the primary-side second resonant reactance element and the primary-side second auxiliary winding portion.

In addition, the primary side switch module includes a first bridge-arm to which 1-1 and 1-2 switching elements are connected in series, and a second bridge to which 1-3 and 1-4 switching elements are connected in series. - an arm and a third bridge-arm to which the 1-5 and 1-6 switching elements are connected in series, wherein the first to third bridge-arms are all connected in parallel, and the primary side first resonance One end of the circuit unit is connected to a node to which the 1-1 and 1-2 switching elements are connected, and the other end is connected to a primary-side central node to which the 1-5 and 1-6 switching elements are connected, and the One end of the primary-side second resonance circuit unit may be connected to a node to which the 1-3 and 1-4 switching elements are connected, and the other end may be connected to the primary-side central node.

In addition, the secondary-side switch module includes a fourth bridge-arm to which 2-1 and 2-2 switching elements are connected in series, and a fifth bridge to which second-3 and 2-4 switching elements are connected in series. - an arm, wherein the secondary-side voltage-dividing capacitor unit includes a secondary-side first voltage-dividing capacitor and a secondary-side second voltage-dividing capacitor connected in series, the second voltage source, the fourth bridge-arm, and the fifth bridge-arm One end of the secondary winding of the first transformer is connected to a node connected in parallel to and to which the 2-1 and 2-2 switching elements are connected, and the 2-3 and 2-4 switching elements are connected One end of the secondary winding of the second transformer is connected to a node to One end of the secondary-side second resonant reactance element is connected, and the other end of the secondary-side first resonant reactance element and the other end of the secondary-side second resonant reactance element are connected through a second common connection line.

In addition, in the forward power transfer mode, the control unit, according to the user's selection, the forward half-bridge operation mode 1, the forward half-bridge operation mode 2 in which the primary circuit part operates as a half-bridge, or the primary circuit part is full - A forward full-bridge operating mode may control the primary side switch module to operate in one of the operating modes of the bridge.

Here, in the bidirectional resonant DC-DC converter according to another embodiment (type 5-1) of the present invention, a diode may be used as the 1-1 switching element and the 1-3 switching element.

In another embodiment (type 4-2) of the bidirectional resonant DC-DC converter of the present invention, the secondary-side switch module includes a fourth bridge to which 2-1 and 2-2 switching elements are connected in series. - an arm and a fifth bridge-arm to which second-3 and 2-4 switching elements are connected in series, wherein the secondary-side voltage divider capacitor includes a secondary-side first voltage divider capacitor and a secondary-side second voltage divider capacitor and one end of the secondary-side first resonant reactance element and one end of the secondary-side second resonant reactance element meet and connect at a secondary-side central node, and the other ends of the secondary-side first voltage divider capacitor and the secondary-side second voltage divider, respectively It is connected to a capacitor, and the other end of the secondary-side first resonant reactance element and the other end of the secondary-side second resonant reactance element are connected through a second common connection line.

One end of the secondary winding of the first transformer is connected to a node to which the 2-1 and 2-2 switching elements are connected, and the second to a node to which the 2-3 and 2-4 switching elements are connected. One end of the secondary winding of the transformer may be connected, and the other end of the secondary winding of the first transformer and the other end of the secondary winding of the second transformer may meet and be connected at the secondary central node.

At this time, in the forward power transfer mode, the control unit according to the user's selection, the forward half-bridge operation mode 1, the forward half-bridge operation mode 2 or the primary circuit unit in which the primary circuit unit operates as a half-bridge The primary side switch module may be controlled to operate in one of the forward full-bridge operation modes operating as a full-bridge.

Here, in the bidirectional resonant DC-DC converter according to another embodiment (type 5-2) of the present invention, a diode may be used as the 1-1 switching element and the 1-3 switching element.

A bidirectional resonant DC-DC converter according to another embodiment (third type) of the present invention is a bidirectional resonant DC-DC including a primary circuit unit connected to a first voltage source and a secondary circuit unit connected to a second voltage source. A converter, wherein the primary-side circuit part includes a primary-side switch module including a plurality of switching elements, a primary-side first resonance circuit part and a primary-side second resonance circuit part, and the secondary-side circuit part includes a plurality of switching elements and a secondary-side switch module, a secondary winding of each of the first transformer and the second transformer, a secondary-side first resonant reactance element, and a secondary-side second resonant reactance element, wherein the primary-side first resonant circuit unit is a first transformer 1 A primary side main winding, a primary side first auxiliary winding unit, and a primary side first resonant reactance element are connected in series, and the primary side second resonant circuit unit includes a second transformer primary side main winding, a primary side second auxiliary winding unit and 1 Secondary-side resonant reactance elements are connected in series, and the primary-side first resonant reactance element, the primary-side second resonant reactance element, the secondary-side first resonant reactance element and the secondary-side second resonant reactance element are resonant capacitors. and a resonance inductor, and a node connected to the primary side main winding of the first transformer and the first auxiliary winding of the primary side of the first resonant circuit part, and the second transformer primary main winding of the primary side second resonance circuit part; The node to which the primary-side second auxiliary winding unit is connected is characterized in that it is connected through a first common connection line.

Here, the primary-side first auxiliary winding unit includes a first auxiliary winding on the primary side of a first transformer and a first auxiliary winding on the primary side of the second transformer, and the second auxiliary winding on the primary side includes a second auxiliary winding on the primary side of the first transformer. and a second auxiliary winding on the primary side of a second transformer, wherein the first main winding on the primary side of the first transformer and the first auxiliary winding on the primary side are wound to have the same polarity, and the secondary main winding on the primary side of the second transformer and the secondary winding on the primary side are wound to have the same polarity. The two auxiliary windings may be wound to have the same polarity, and one of the first transformer secondary winding and the second transformer secondary winding may be wound to have different polarities.

In addition, in the forward power transfer mode, a current flows through the primary-side first resonant reactance element and the primary-side second resonant reactance element, and a current flows through the secondary-side first resonant reactance element and the secondary-side second resonant reactance element. does not flow, and in the reverse power transfer mode, current flows in the secondary-side first resonant reactance element and the secondary-side second resonant reactance element, and the primary-side first resonant reactance element, the primary-side first auxiliary winding unit and the It is characterized in that no current flows between the primary-side second resonant reactance element and the primary-side second auxiliary winding portion.

In addition, the primary side switch module includes a first bridge-arm to which 1-1 and 1-2 switching elements are connected in series, and a second bridge to which 1-3 and 1-4 switching elements are connected in series. - an arm and a third bridge-arm to which the 1-5 and 1-6 switching elements are connected in series, wherein the first to third bridge-arms are all connected in parallel, and the primary side first resonance One end of the circuit unit is connected to a node to which the 1-1 and 1-2 switching elements are connected, and the other end is connected to a primary-side central node to which the 1-5 and 1-6 switching elements are connected. One end of the secondary-side second resonance circuit unit may be connected to a node to which the 1-3 and 1-4 switching elements are connected, and the other end may be connected to the primary-side central node.

In addition, the secondary-side switch module includes a fourth bridge-arm in which 2-1 and 2-2 switching elements are connected in series, and a fifth bridge in which second-3 and 2-4 switching elements are connected in series. - an arm and a sixth bridge-arm to which second-5 and second-6 switching elements are connected in series, wherein the fourth to sixth bridge-arms are all connected in parallel, and the 2-1 and One end of the secondary winding of the first transformer is connected to a node to which the 2-2 switching element is connected, and one end of the secondary winding of the second transformer is connected to the node to which the 2-3 and 2-4 switching elements are connected. is connected, and one end of the secondary-side first resonant reactance element and one end of the secondary-side second resonant reactance element are connected to the secondary-side central node to which the 2-5 and 2-6 switching elements are connected; The other end of the first resonant reactance element and the other end of the second resonant reactance element are connected through a second common connection line.

In addition, in the forward power transfer mode, the control unit, according to the user's selection, the forward half-bridge operation mode 1, the forward half-bridge operation mode 2 in which the primary circuit part operates as a half-bridge, or the primary circuit part is full - A forward full-bridge operating mode may control the primary side switch module to operate in one of the operating modes of the bridge.

In addition, in the reverse power transfer mode, the control unit, according to a user's selection, a reverse half-bridge operation mode 1 in which the secondary circuit unit operates as a half-bridge, a reverse half-bridge operation mode 2 or the secondary circuit unit The secondary-side switch module may be controlled to operate in one of the reverse full-bridge operation modes operating as a full-bridge.

Here, the bidirectional resonant DC-DC converter according to another embodiment (type 5-3) of the present invention includes the 1-1 switching element, the 1-3 switching element, the 2-1 switching element, and the A diode may be used as the second-3 switching element.

Meanwhile, in embodiments of the present invention, the first transformer primary-side main winding and the second transformer primary-side main winding may include leakage inductance.

In this case, the first primary side main winding of the transformer and the second transformer primary side main winding may include a resonance inductor instead of the leakage inductance.

When applying the existing bi-directional resonant converter, it was difficult to obtain the desired gain characteristics because the resonant converter was applied to the primary side and the secondary side, so that it was coupled to each other and had the CLLC resonance gain characteristic.

In the case of the bidirectional resonant DC-DC converter proposed in the present invention, even if the resonant capacitor is applied to the primary circuit part and the secondary circuit part, it does not have a mutually coupled DLLC resonance characteristic and the transformer winding polarity (gain control) of the two resonance circuit parts. For this purpose, the main winding and auxiliary winding are applied) and the operation characteristics according to the common connection line make it easy to adjust the gain by operating with the unique gain characteristics of the LLC resonant converter, respectively, during forward and reverse power transfer operation, and wide input/output It is possible to provide a high-efficiency bidirectional DC-DC converter having a characteristic that can operate with a voltage control range.

In addition, the present invention can provide a bidirectional DC-DC converter capable of controlling gain by a variable switching frequency during operation of a main circuit for power transfer in forward and reverse directions.

In addition, the present invention can provide a bidirectional resonant DC-DC converter that proposes more easily manufactured main circuits by applying a primary-side auxiliary winding to the primary-side main winding and the primary-side resonant reactance in series.

In addition, the present invention is to provide a bidirectional resonant DC-DC converter capable of easily increasing the capacity in which the main circuits proposed can be connected in parallel by connecting the primary side central node and the secondary side central node, respectively. can

1 shows an example of a conventional bidirectional resonant DC-DC converter.
2A shows a preferred LLC gain characteristic of a bidirectional resonant DC-DC converter.
2B and 2C show the CLLC and SRC gain characteristics of a conventional bidirectional resonant DC-DC converter.
3A is a circuit diagram illustrating a first type main circuit of a bidirectional resonant DC-DC converter according to an embodiment of the present invention.
3B shows an equivalent circuit in a forward power transfer mode of a first type main circuit of a bidirectional resonant DC-DC converter according to an embodiment of the present invention.
3C shows the voltage gain characteristics in the forward power transfer mode of the first type main circuit.
3D and 3E show detailed operations in the forward power transfer mode of the first type main circuit of the bidirectional resonant DC-DC converter according to an embodiment of the present invention.
3F illustrates voltage and current waveforms in a forward power transfer mode of a first type main circuit of a bidirectional resonant DC-DC converter according to an embodiment of the present invention.
3G shows an equivalent circuit in a reverse power transfer mode of the first type main circuit of the bidirectional resonant DC-DC converter according to an embodiment of the present invention.
3H shows the voltage gain characteristics in the reverse power transfer mode of the first type main circuit.
3I and 3J show detailed operations in the reverse power transfer mode of the first type main circuit of the bidirectional resonant DC-DC converter according to an embodiment of the present invention.
3K illustrates voltage and current waveforms in a reverse power transfer mode of a first type main circuit of a bidirectional resonant DC-DC converter according to an embodiment of the present invention.
4A is a circuit diagram illustrating a second type main circuit of a bidirectional resonant DC-DC converter according to an embodiment of the present invention.
4B shows the voltage gain characteristics in the forward power transfer mode of the second type main circuit.
4C and 4D are diagrams illustrating detailed operations of the forward half-bridge operation mode 1 of the second type main circuit of the bidirectional resonant DC-DC converter according to an embodiment of the present invention.
4E is a diagram illustrating voltage and current waveforms in forward half-bridge operation mode 1 of a second type main circuit of a bidirectional resonant DC-DC converter according to an embodiment of the present invention.
4F and 4G are diagrams illustrating detailed operations of the forward half-bridge operation mode 2 of the second type main circuit of the bidirectional resonant DC-DC converter according to an embodiment of the present invention.
4H illustrates voltage and current waveforms in forward half-bridge operation mode 2 of the second type main circuit of the bidirectional resonant DC-DC converter according to an embodiment of the present invention.
4I and 4J are diagrams illustrating detailed operations of the forward full-bridge operation mode of the second type main circuit of the bidirectional resonant DC-DC converter according to an embodiment of the present invention.
4K illustrates voltage and current waveforms in a forward full-bridge operation mode of a second type main circuit of a bidirectional resonant DC-DC converter according to an embodiment of the present invention.
FIG. 4L is a diagram illustrating voltage gain characteristics in a reverse power transfer mode of a second type main circuit of a bidirectional resonant DC-DC converter according to an embodiment of the present invention.
4M and 4N show detailed operations of the reverse power transfer mode of the second type main circuit of the bidirectional resonant DC-DC converter according to an embodiment of the present invention.
4O is a diagram illustrating voltage and current waveforms in a reverse power transfer mode of a second type main circuit of a bidirectional resonant DC-DC converter according to an embodiment of the present invention.
5A is a circuit diagram illustrating a third type main circuit of a bidirectional resonant DC-DC converter according to an embodiment of the present invention.
5B shows the voltage gain characteristics in the forward power transfer mode of the third type main circuit.
5c and 5d respectively show voltage and current waveforms in forward half-bridge operation mode 1 and forward full-bridge operation mode of the third type main circuit of the bidirectional resonant DC-DC converter according to an embodiment of the present invention; it will be shown
5E is a diagram illustrating voltage gain characteristics in a reverse power transfer mode of a third type main circuit of a bidirectional resonant DC-DC converter according to an embodiment of the present invention.
5f and 5g show voltage and current waveforms in reverse half-bridge operation mode 1 and reverse full-bridge operation mode of the third type main circuit of the bidirectional resonant DC-DC converter according to an embodiment of the present invention, respectively. it will be shown
6A is a circuit diagram illustrating a 4-1 type main circuit of a bidirectional resonant DC-DC converter according to an embodiment of the present invention.
6B is a circuit diagram illustrating a 4-2 type main circuit of a bidirectional resonant DC-DC converter according to an embodiment of the present invention.
6C is a circuit diagram in which a switching element is applied instead of a secondary side voltage divider capacitor in a 4-2 type main circuit of a bidirectional resonant DC-DC converter according to an embodiment of the present invention.
7 is a circuit diagram illustrating a fifth type main circuit of a bidirectional resonant DC-DC converter according to an embodiment of the present invention.
8 is a table showing main ratings, specifications, and transformer parameters applied in an experiment on the gain characteristics of the bidirectional resonant DC-DC converter of the present invention.
9 is an experimental waveform during the forward power transfer mode operation for the first type main circuit.
10 is a diagram illustrating efficiency characteristics of a first type main circuit in a forward power transfer mode operation.
11 is an experimental waveform of the reverse power transfer mode operation for the first type main circuit.
12 is a diagram illustrating efficiency characteristics in a forward power transfer mode operation for a first type main circuit.

The objects, features and advantages of the present invention described above will become more apparent through the following examples in conjunction with the accompanying drawings. The following specific structural or functional descriptions are only exemplified for the purpose of describing embodiments according to the concept of the present invention, and the embodiments according to the concept of the present invention may be implemented in various forms and described in the present specification or application. It should not be construed as being limited to the examples. Since the embodiment according to the concept of the present invention may have various changes and may have various forms, specific embodiments are illustrated in the drawings and described in detail in the present specification or application. However, this is not intended to limit the embodiments according to the concept of the present invention to a specific disclosed form, and should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention. Terms such as first and/or second may be used to describe various elements, but the elements are not limited to the terms. The above terms are used only for the purpose of distinguishing one element from other elements, for example, without departing from the scope of the present invention, a first element may be called a second element, and similar For example, the second component may also be referred to as the first component. When a component is referred to as being connected or connected to another component, it may be directly connected or connected to the other component, but it should be understood that another component may exist in between. On the other hand, when it is mentioned that a certain element is directly connected to or directly connected to another element, it should be understood that the other element does not exist in the middle. Other expressions for describing the relationship between elements, such as between and immediately between, or adjacent to and directly adjacent to,, etc., should be interpreted similarly. The terms used herein are used only to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In this specification, the terms include or have are intended to designate that the specified feature, number, step, action, component, part, or combination thereof exists, and includes one or more other features or numbers, steps, actions, It should be understood that the possibility of the presence or addition of components, parts or combinations thereof is not precluded in advance. Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present specification. does not Hereinafter, the present invention will be described in detail by describing preferred embodiments of the present invention with reference to the accompanying drawings. Like reference numerals in each figure indicate like elements.

3A is a circuit diagram illustrating a first type main circuit of a bidirectional resonant DC-DC converter according to an embodiment of the present invention.

Referring to FIG. 3A , the first type main circuit of the bidirectional resonant DC-DC converter according to an embodiment of the present invention includes a primary side circuit unit 1100 and a secondary side circuit unit 1200 . In this case, the primary circuit unit 1100 is connected to the first voltage source 10 , and the secondary circuit unit 1200 is connected to the second voltage source 20 .

In this case, each of the first voltage source 10 and the second voltage source 20 may include at least one of a DC voltage source, a battery, a capacitor, and a load.

Here, the primary-side circuit unit 1100 includes a primary-side switch module Q1 to Q4 including a plurality of switching elements, a primary-side voltage dividing capacitor unit, a primary-side first resonance circuit unit, and a primary-side second resonance circuit unit, 2 The secondary-side circuit unit 1200 includes a secondary-side switch module (S1 to S4) including a plurality of switching elements, a secondary-side voltage dividing capacitor unit, and a secondary winding (NS1) of each of the first transformer (T1) and the second transformer (T2); NS2), a secondary-side first resonant reactance element 1211 and a secondary-side second resonant reactance element 1212 .

At this time, the primary side switch module (Q1 ~ Q4), the 1-1 and 1-2 switching elements (Q1-Q2) are connected in series to the first bridge-arm (Bridge-Leg) and 1-3 and a second bridge-arm to which the 1-4 th switching elements Q3-Q4 are connected in series, and the secondary-side switch modules S1 to S4 include the 2-1 th and 2-2 th switching elements S1. -S2) includes a third bridge-arm connected in series and a fourth bridge-arm connected in series with the 2-3rd and 2-4th switching elements S3-S4.

In addition, the primary-side first resonant circuit unit may include the first transformer primary-side main winding NP1, the primary-side first auxiliary winding units NP11 and NP21, and the primary-side first resonant reactance element 1111, all in series. One end of the primary-side first resonance circuit unit is connected to a node to which the 1-1 and 1-2 switching elements Q1-Q2 are connected, and the other end of the primary-side first voltage divider capacitor C1 and the primary-side second switching element Q1-Q2 is connected. It is connected to the primary side central node (node 'X') to which the voltage dividing capacitor C2 is connected.

In addition, the primary-side second resonant circuit unit may include the second transformer primary-side main winding NP2, the primary-side second auxiliary winding units NP12 and NP22, and the primary-side second resonant reactance element 1112, all in series. One end of the primary-side second resonance circuit unit is connected to a node to which the 1-3 and 1-4 switching elements Q3-Q4 are connected, and the other end is connected to the primary-side central node (node 'X'). .

The primary-side first auxiliary winding unit NP11 and NP21 includes a first transformer primary-side first auxiliary winding NP11 and a second transformer primary-side first auxiliary winding NP21, and the primary-side second auxiliary winding unit ( NP12 and NP22 include a second auxiliary winding NP12 on the primary side of the first transformer and a second auxiliary winding NP22 on the primary side of the second transformer.

The primary-side voltage-dividing capacitor unit includes a primary-side first voltage-dividing capacitor C1 and a primary-side second voltage-dividing capacitor C2 connected in series, and includes a first voltage source 10 , a first bridge-arm and a second bridge-arm. connected in parallel with

The secondary-side voltage-dividing capacitor unit includes a secondary-side first voltage-dividing capacitor C3 and a secondary-side second voltage-dividing capacitor C4 connected in series to a second voltage source 20 , a third bridge-arm and a fourth bridge-arm; connected in parallel

In addition, one end of the first transformer secondary winding NS1 is connected to the node to which the 2-1 and 2-2 switching elements S1-S2 are connected, and the 2-3 and 2-4 switching elements (S1 - S2) are connected to each other. One end of the secondary winding NS2 of the second transformer is connected to the node to which S3-S4 is connected.

In addition, one end and the secondary side of the secondary-side first resonance reactance element 1211 are connected to the secondary-side central node (node 'Y') to which the secondary-side first voltage-dividing capacitor C3 and the secondary-side second voltage-dividing capacitor C4 are connected. One end of the second resonant reactance element 1212 is connected.

The resonant reactance elements 1111 , 1112 , 1211 , and 1212 include a resonant capacitor and a resonant inductor, and may be configured with various types of filter circuits.

In addition, the bidirectional resonant DC-DC converter according to an embodiment of the present invention may include a control unit (not shown) for controlling the primary side switch modules (Q1 to Q4) and the secondary side switch modules (S1 to S4). . The control unit controls the switching elements of the primary side switch modules (Q1 to Q4) and the secondary side switch modules (S1 to S4) to transfer electrical energy in both directions between the first voltage source 10 and the second voltage source 20, but 1 By varying the switching frequency for at least one of the secondary-side switch modules Q1 to Q4 and the secondary-side switch modules S1 to S4, the voltage gain, which is the magnitude of the output voltage relative to the input voltage magnitude, may be controlled.

In addition, the control unit, a forward power transfer mode for transferring electrical energy from the first voltage source 10 to the second voltage source 20 and a reverse power transfer for transferring electrical energy from the second voltage source 20 to the first voltage source 10 . In the same mode, the voltage gain can be decreased by increasing the switching frequency, and the voltage gain can be increased by decreasing the switching frequency.

More specifically, there are two switching elements at both ends of the primary circuit unit 1100 and the secondary circuit unit 1200 (primary circuit units: Q1-Q2, Q3-Q4, secondary circuit units: S1-S2, S3-S4) The bridge-arms connected in series and two voltage dividing capacitors (primary side: C1-C2, secondary side: C3-C4) are connected in parallel, respectively. Between the source and drain of each bridge-arm switching element (Primary: Q1-Q2, Q3-Q4, Secondary: S1-S2, S3-S4) and the voltage divider capacitor (Primary: C1-C2, Secondary: C3) -C4) Resonant reactance elements 1111, 1112, 1211, 1212 (primary side: Cr1/Cr2, secondary side: CR1/CR2) or resonant capacitors, resonant inductors, and various resonant circuits are located between the central node. can be replaced) and each transformer primary and secondary windings (primary: NP1-NP11-NP21, NP2-NP12-NP22 / secondary: NS1, NS2) are connected in series, respectively, and a resonant reactance element (primary: Cr1/Cr2, secondary side: CR1/CR2) One end is connected between the central node of the voltage dividing capacitor (primary side: C1-C2, secondary side: C3-C4).

In addition, the first transformer primary side main winding (NP1) and the primary side first auxiliary winding units (NP11, NP21) are connected to the connection part of the first resonant circuit part of the primary side, and the second transformer of the primary side second resonance circuit part The connection part where the primary side main winding NP2 and the primary side secondary winding parts NP12 and NP22 are connected is connected to each other through a first common connection line, and the other end of the secondary side first resonance reactance 1211 and the The other end 1212 of the secondary-side second resonance reactance is connected to each other through a second common connection line.

By the second common connection line of the secondary side circuit unit 1200, in the forward power transfer mode, a current flows through the primary side first resonant reactance element 1111 and the primary side second resonant reactance element 1112, and the secondary side first No current flows through the resonant reactance element 1211 and the secondary-side second resonant reactance element 1212 .

In addition, by the first common connection line of the primary side circuit unit 1100, in the reverse power transfer mode, a current flows through the secondary side first resonant reactance element 1211 and the secondary side second resonant reactance element 1212, 1 No current flows in the primary side first resonant reactance element 1111, the primary side first auxiliary winding units NP11 and NP21, the primary side second resonant reactance element 1112 and the primary side second auxiliary winding unit NP12, NP22 does not

In addition, the primary windings (primary winding and auxiliary winding NP1, NP11, NP12, NP2, NP21, NP22) of the transformers (T1, T2) of the first and second resonance circuits of the primary side have opposite polarities (or opposite polarities) , and the polarity of one of the secondary windings NS1 and NS2 of the transformers T1 and T2 has a different polarity from the polarity of the primary winding transformer.

In other words, the first transformer primary side main winding NP1 and the primary side first auxiliary winding parts NP11 and NP21 are wound to have the same polarity, and the second transformer primary side main winding NP2 and the primary side secondary winding part are wound to have the same polarity. The parts NP12 and NP22 are wound to have the same polarity, and one of the first transformer secondary winding NS1 and the second transformer secondary winding NS2 is wound to have a different polarity.

Therefore, in the forward and reverse power transmission, the resonance current does not flow through the resonance reactance elements 1111, 1112, 1211, 1212 according to the voltage polarity of the windings of the primary and secondary side transformers T1 and T2 during the rectification operation, and the first and second 2 By bypassing and rectifying through a common connection line, it has unique LLC resonance characteristics and can transmit power in both directions.

In addition, the first transformer primary side main winding NP1 and the second transformer primary side main winding NP2 may include leakage inductances LlP1 and LlP2, and a resonance inductor may be included instead of the leakage inductance LlP1 and LlP2. can

In addition, leakage inductances LlS1 and Lls2 may be included in the first transformer secondary winding NS1 and the second transformer secondary winding NS2. may be included.

As described above, in the case of a conventional bidirectional DLL3 resonant converter, since the primary side and the secondary side resonant capacitors are coupled, it is difficult to control the gain in a frequency range lower than the resonant frequency, and thus the variable switching frequency control operation has limitations. On the other hand, in the present invention, even when the resonant capacitor is applied to the primary side and the secondary side, the LLC resonant converter can operate with the inherent gain characteristics during forward and reverse operation, so that it is possible to easily transfer power in both directions by the variable switching frequency control operation. It works.

3B is an equivalent circuit in the forward power transfer mode of the first type main circuit of the bidirectional resonant DC-DC converter according to an embodiment of the present invention, and FIG. 3C is the first type main circuit in the forward power transfer mode. Voltage gain characteristics are shown.

In the operation of the primary circuit unit 1100 , the switching elements Q1 and Q2 and the switching elements Q3 and Q4 alternately operate with a duty of 50%, and Q1 and Q3, Q2 and Q4 simultaneously turn-on and turn-off operations and 1/2 of the input voltage (VIN) is applied to the first and second resonance circuits on the primary side, and the resonance voltage is applied to the primary windings (NP1, NP2) and auxiliary windings (NP11-NP21, NP12-NP22) of each transformer. this is authorized The switching elements S1 , S2 , S3 , and S4 of the secondary circuit unit 1200 are turned off and only rectify through an anti-parallel diode of the switching element (but may also be applied as a synchronous rectifier if necessary). At this time, as the sum voltage (VS1+VS2) is applied by the voltage polarity of the secondary windings NS1 and NS2 of each of the transformers T1 and T2 applied, the secondary-side first and second resonant capacitors CR1 and CR2 are connected. The current does not flow through it, but flows in a detour through the second common connection line and is rectified to the output terminal through the anti-parallel diode of the secondary side switching elements (S2/S3, S1/S4) to transmit power in the forward direction.

Accordingly, during the forward power transfer mode operation, the primary-side first and second resonant capacitors Cr1 and Cr2 and the secondary-side first and second resonant capacitors CR1 and CR2 are operated without mutual coupling, and the primary-side first resonant capacitors Cr1 and Cr2 are operated without mutual coupling. , The second resonant circuit unit is operated in parallel, but since the secondary windings NS1 and NS2 are connected in series by the voltage polarity of the transformer, they can be operated without current imbalance.

Referring to the equivalent circuit of FIG. 3B and examining the gain characteristics using the superposition principle, the LLC resonant converter has a unique gain characteristic, so that gain control can be performed through the variable switching frequency control as shown in FIG. 3C . At this time, by applying auxiliary windings (NP11-NP21, NP12-NP22) to the transformers (T1, T2) of the first and second resonance circuits of the primary side, the turn-defense of the transformers (T1, T2) when operating in the forward power transfer mode ( By NS1/(NP1+NP11+NP21), NS2/(NP2+NP12+NP22)), the output terminal voltage of the secondary side circuit unit 1200 may be controlled by lowering the gain by the turn-defense.

3D and 3E are detailed operations in the forward power transfer mode of the first type main circuit of the bidirectional resonant DC-DC converter according to an embodiment of the present invention, and FIG. 3F shows voltage and current waveforms at this time. did it

Hereinafter, a detailed operation in the forward power transfer mode of the first type of the main circuit will be described by dividing it into four sections with reference to FIGS. 3D, 3E, and 3F.

(1) t0-t1 interval

During this period, the switching elements Q1 and Q3 of the primary side circuit unit 1100 are turned on under the zero voltage switching (ZVS) condition, and 1/2 of the input voltage (Vin) is 1 Transformers (T1, T2) in the first and second resonance circuits on the primary side, respectively, applied to the first and second resonant circuit units on the primary side The resonance voltage is applied to the , and the resonance currents IP1 and IP2 branch and flow in parallel, and the load resonance currents IS1 and IS2 are transferred to the secondary circuit unit 1200 . At this time, the load resonance current IS1, IS2) does not flow, but is connected and flows through the bypassing second common connection line, and the sum voltage (VS1+VS2) is transmitted to the load terminal. At this time, auxiliary windings (NP11-NP21, NP12-NP22) are applied to the first and second resonant circuit part transformers (T1, T2) of the primary side circuit part 1100. When operating in the forward power transfer mode, the transformers (T1, T2) The turn-defence (NS1/(NP1+NP11+NP21), NS2/(NP2+NP12+NP22)) of the output terminal voltage of the secondary side circuit unit 1200 is operated by lowering the gain by the turn-defense.

(2) t1-t2 interval

At time t1, the main switching elements Q1 and Q3 of the primary circuit unit 1100 are continuously turned on and operate in a frequency range lower than the resonance frequency fr, so that the resonance current ends and only magnetizing currents ImP1 and ImP2 flow Therefore, the load resonance current (IS1=IS2=0) does not flow in the secondary side circuit unit 1200, and the voltage of the secondary side first and second voltage dividing capacitors (C3+C4) is only discharged through the load.

(3) t2-t3 section

When the switching elements Q1 and Q3 are turned off at the time t2, the parasitic capacitance (Cp) of Q1 and Q3 during the dead-time by the magnetizing currents (ImP1, ImP2) of the transformers (T1, T2) starts charging and is charged to the input voltage (Vin), and the voltage of the parasitic capacitance (Cp) of Q2 and Q4 starts discharging and discharges to 0 voltage, then turns on when the current flows through the antiparallel diodes of Q2 and Q4 - When on, zero voltage switching operates and this mode ends. At this time, since the voltage polarity applied to the primary side transformers (T1, T2) is changed during the dead time, the voltage polarity of the transformer secondary side windings (NS1, NS2) is also changed so that the load resonance current (IS1 = IS2) is changed to the secondary side first and second 2 It does not flow through the resonance capacitors CR1 and CR2, but starts to flow through the bypassing second common connection line, and the sum voltage (VS1+VS2) of the secondary winding of the transformer starts to be applied to the output load terminal.

(4) t3-t4 section

In the period t3-t4, at the time t3, the primary side main switching devices Q2 and Q4 are turned on at zero voltage, and 1/2 of the input voltage Vin is applied to the primary side first and second resonance circuits, respectively, and each Resonant voltage is applied to the primary side main windings (NP1, NP2) and auxiliary windings (NP11-NP21, NP12-NP22) of the transformer (T1, T2) in the resonance circuit part, and the resonance currents (IP1, IP2) branch and flow in parallel. In the secondary-side rectifier, the sum voltage (VS1+VS2) is applied to the output load end according to the voltage polarity of each winding of the transformer (T1, T2), so that the load resonance current (IS=IS1=IS2) is It continues to flow through the second common connection line that bypasses the resonance capacitors CR1 and CR2.

After that, since the remaining sections t4-t5 and t5-t6 operate repeatedly with the previous half cycle, a description of the subsequent operation is not described.

3G is an equivalent circuit in the reverse power transfer mode of the first type main circuit of the bidirectional resonant DC-DC converter according to an embodiment of the present invention, and FIG. 3H is the first type main circuit in the reverse power transfer mode. Voltage gain characteristics are shown.

The switching elements Q1, Q2, Q3, and Q4 of the primary side circuit unit 1100 are turned off, and the rectification operation is performed through an anti-parallel diode (it may also be operated as a synchronous rectifier), and the secondary side circuit unit 1200 is switched. The elements S1 and S2, S3 and S4 operate alternately with a duty of 50%, and S1 and S3, S2 and S4 simultaneously turn-on and turn-off, and output terminals in the first and second resonance circuits of the secondary side. 1/2 of the voltage _VO is applied, respectively, and a resonance voltage is applied to the secondary windings NS1 and NS2 of the transformers T1 and T2.

Here, the secondary-side first resonant circuit unit includes a secondary-side first resonant reactance element 1211 , a first transformer secondary winding NS1 and a secondary-side first transformer leakage inductance, and the secondary-side second resonant circuit unit includes: and a secondary secondary resonant reactance element 1212 , a secondary transformer secondary winding NS2 and a secondary secondary transformer leakage inductance.

At this time, the voltage polarity of the primary windings (NP1, NP2) is changed by the applied voltage of the secondary windings (NS1, NS2) of the transformer (T1, T2) and the sum voltage (N'Vo = VP1+VP2, N' = NP1) /NS1 = NP2/NS2) is applied, and the sum of voltages (VNP11+VNP21, VNS12+VNP22) of the first and second auxiliary windings connected to the first and second resonance circuits on the primary side in the first common connection line is 0, no current flows through each of the first and second resonant capacitors Cr1 and Cr2 on the primary side, the first auxiliary winding units NP11 and NP21 on the primary side and the second auxiliary winding units NP12 and NP22 on the primary side, As it flows in a detour through the first common connection line, it is rectified to the input terminal through an anti-parallel diode of the primary side switching element to transmit power in the reverse direction.

At this time, by applying auxiliary windings (NP11-NP21, NP12-NP22) to the transformers (T1, T2) of the first and second resonance circuits of the primary side, the primary side during the reverse power transfer mode operation is different from the forward power transfer mode operation. Power can be transferred to the input terminal of the circuit unit 1100 by lowering the voltage by the turn-defenses NP1/NS1 and NP2/NS2 of the transformers T1 and T2. By applying auxiliary windings (NP11-NP21, NP12-NP22), it is possible to easily adjust the gain voltage control range according to battery charging and discharging voltages during forward and reverse power transfer mode operation.

According to the influence of the transformer leakage inductance, the gain according to DC Offset increases when operating in forward and reverse power transfer mode. In order to operate the battery full charge voltage in the reverse power transfer mode, it must be operated in a switching frequency region higher than the resonance frequency. there is.

Therefore, when operating in forward power transfer mode by applying auxiliary windings (NP11-NP21, NP12-NP22), turn-defense of transformers (T1, T2) (NS1/(NP1+NP11+NP21), NS2/(NP2+NP12+) NP22)), but operates with turn-defense (NP1/NS1, NP2/NS2) of transformers (T1, T2) excluding auxiliary windings (NP11-NP21, NP12-NP22) when operating in reverse power transfer mode Thus, the gain is lowered, so that the variable switching frequency control range can be the same when operating in the forward and reverse power transfer modes.

Also, the secondary-side first and second resonant capacitors CR1 and CR2 and the primary-side first and second resonant capacitors Cr1 and Cr2 are not mutually coupled to each other even during the reverse power transfer mode operation as in the forward power transfer mode operation. The secondary windings NS1 and NS2 of the transformers T1 and T2 are operated in parallel, but the primary windings NP1 and NP2 are operated in series by the voltage polarity of the transformers T1 and T2, so there is no current imbalance. It works.

When the gain characteristics are reviewed using the equivalent circuit of FIG. 3G, even when operating in the reverse power transfer mode, the LLC resonant converter has a unique gain characteristic. As shown in FIG. 3H, gain control can be performed through the variable switching frequency control.

3I and 3J are detailed operations in the reverse power transfer mode of the first type main circuit of the bidirectional resonant DC-DC converter according to an embodiment of the present invention, and FIG. 3K shows voltage and current waveforms at this time. did it

Hereinafter, a detailed operation in the reverse power transfer mode of the first type of the main circuit will be described by dividing it into four sections with reference to FIGS. 3I to 3K .

(1) t0-t1 interval

During this period, the switching elements S1 and S3 of the secondary side circuit unit 1200 are turned on in the zero voltage switching condition, and 1/2 of the output voltage Vo is applied to the secondary side first and second resonance circuit units, Resonant voltage is applied to the first and second transformer secondary windings NS1 and NS2 in each resonance circuit unit, and the resonance currents IS1 and IS2 branch and flow in parallel, and the primary side resonance currents IP1 and IP2 are switched to the switching element. It is transmitted to the input power stage through the antiparallel diode of (Q2/Q3, Q1/Q4).

Here, the secondary-side first resonant circuit unit includes a first transformer secondary-side winding NS1 and a secondary-side first resonant reactance element 1211 , and the secondary-side second resonant circuit unit includes a second transformer secondary winding NS2 and 2 A secondary-side second resonant reactance element 1212 is included.

At this time, the resonance currents (IP1, IP2) do not flow through the primary side first and second resonance capacitors (Cr1, Cr2) by the voltage polarity of the primary side main windings (NP1, NP2) of the transformers (T1, T2). They are connected and flow through the first common connection line, and the sum voltage VP1 + VP2 is transmitted to the input terminal. At this time, the auxiliary windings (NP11-NP21, NP12-NP22) are applied to the transformers (T1, T2) of the first and second resonance circuits on the primary side, but the The sum becomes 0, and when operating in the reverse power transfer mode, the gain is lowered by the turn-defense of the transformer (N' = NP1/NS1 = NP2/NS2).

(2) t1-t2 interval

At time t1, the main switching elements S1 and S3 of the secondary side circuit unit 1200 are continuously turned on and operate in a frequency range lower than the resonance frequency fr, so that the resonance current ends and only the secondary magnetization currents ImS1 and ImS2 are Because it flows, the load resonance current (IP1=IP2=0) does not flow in the primary side circuit, and the voltage of the primary side first and second voltage divider capacitors (C1+C2) is only discharged through the load.

(3) t2-t3 section

When the switching elements S1 and S3 are turned off at the time t2, the secondary circuit part transformers (T1, T2) start charging the parasitic capacitances (Cs) of S1 and S3 during the dead time by the magnetizing currents (ImS1, ImS2) to the output terminal voltage. It is charged to (Vo), and the voltage of the parasitic capacitance (Cp) of S2 and S4 starts discharging and discharges to zero voltage. Then, when the current flows through the antiparallel diodes of S2 and S4, when the voltage is turned on, zero voltage switching operation is performed. and this mode ends.

At this time, since the voltage polarity applied to the secondary side transformers (T1, T2) is changed during the dead time, the voltage polarity of the primary side main windings (NP1, NP2) of the transformer is also changed, so that the load resonance current (IP1 = IP2) changes to the primary side first and second 2 It does not flow through the resonance capacitors (Cr1, Cr2), but starts to flow through the bypassing first common connection line, and the sum voltage (VP1+VP2) of the primary windings of the transformers (T1, T2) starts to be applied to the input power terminal .

(4) t3-t4 section

In the period t3-t4, at time t3, the main switching devices S2 and S4 of the secondary side circuit unit 1200 are turned on at zero voltage, and 1/2 of the output voltage Vo is applied to the secondary side first and second resonance circuits. is applied, and a resonance voltage is applied to the secondary windings NS1 and NS2 of the transformers T1 and T2 in each of the first and second resonance circuits of the secondary side, and the resonance currents IS1 and IS2 are branched and flowed in parallel, and the primary side rectifying part The sum voltage (VP1 + VP2) is transmitted to the input power terminal according to the voltage polarity of the windings of the transformer (T1, T2), so that the resonance current (IP=IP1=IP2) of the primary side first and second resonance capacitors (Cr1, Cr2) is ), it continues to flow through the first common connection line that bypasses it.

After that, since the remaining sections t4-t5 and t5-t6 operate repeatedly with the previous half cycle, a description of the subsequent operation is not described.

4A is a circuit diagram illustrating a second type main circuit of a bidirectional resonant DC-DC converter according to an embodiment of the present invention, and FIG. 4B is a voltage gain characteristic of the second type main circuit in a forward power transfer mode. did it

Referring to FIG. 4A , the second type main circuit of the bidirectional resonant DC-DC converter according to an embodiment of the present invention includes a primary side circuit unit 1100 and a secondary side circuit unit 1200 . In this case, the primary circuit unit 1100 is connected to the first voltage source 10 , and the secondary circuit unit 1200 is connected to the second voltage source 20 .

In this case, each of the first voltage source 10 and the second voltage source 20 may include at least one of a DC voltage source, a battery, a capacitor, and a load.

Here, the primary-side circuit unit 1100 includes primary-side switch modules Q1 to Q6 including a plurality of switching elements, a primary-side first resonant circuit unit and a primary-side second resonant circuit unit, and the secondary-side circuit unit 1200 includes A secondary side switch module (S1 ~ S6) including a plurality of switching elements, a secondary side voltage dividing capacitor unit, the secondary side windings (NS1, NS2) of each of the first transformer (T1) and the second transformer (T2), the secondary side second It includes a first resonant reactance element 1211 and a secondary-side second resonant reactance element 1212 .

At this time, the primary-side switch module (Q1 ~ Q6), the first bridge-arm, 1-3 and 1-4 first bridge-arm to which the 1-1 and 1-2 switching elements (Q1-Q2) are connected in series a second bridge-arm to which the switching elements Q3-Q4 are connected in series and a third bridge-arm to which the 1-5 and 1-6 switching elements Q5-Q6 are connected in series; to the third bridge-arm are all connected in parallel.

In addition, the primary-side first resonant circuit unit may include the first transformer primary-side main winding NP1, the primary-side first auxiliary winding units NP11 and NP21, and the primary-side first resonant reactance element 1111, all in series. One end of the primary-side first resonance circuit unit is connected to a node to which the 1-1 and 1-2 switching elements Q1-Q2 are connected, and the other end of the first-side first resonant circuit unit is connected to the 1-5 and 1-6 switching devices. It is connected to the primary side central node (node 'X') to which the elements Q5-Q6 are connected.

In addition, the primary-side second resonant circuit unit may include the second transformer primary-side main winding NP2, the primary-side second auxiliary winding units NP12 and NP22, and the primary-side second resonant reactance element 1112, all in series. One end of the primary-side second resonance circuit unit is connected to a node to which the 1-3 and 1-4 switching elements Q3-Q4 are connected, and the other end is connected to the primary-side central node (node 'X'). .

The primary-side first auxiliary winding unit NP11 and NP21 includes a first transformer primary-side first auxiliary winding NP11 and a second transformer primary-side first auxiliary winding NP21, and the primary-side second auxiliary winding unit ( NP12 and NP22 include a second auxiliary winding NP12 on the primary side of the first transformer and a second auxiliary winding NP22 on the primary side of the second transformer.

The secondary-side switch module (S1 to S4) includes a fourth bridge-arm to which the 2-1 and 2-2 switching elements (S1-S2) are connected in series and the 2-3 and 2-4 switching elements ( S3-S4) includes a fifth bridge-arm connected in series.

The secondary-side voltage-dividing capacitor unit includes the secondary-side first voltage-dividing capacitor C3 and the secondary-side second voltage-dividing capacitor C4 connected in series to the second voltage source 20 , the fourth bridge-arm and the fifth bridge-arm. connected in parallel with

At this time, one end of the first transformer secondary winding NS1 is connected to a node to which the 2-1 and 2-2 switching elements S1-S2 are connected, and the 2-3 and 2-4 switching elements are connected. One end of the secondary winding NS2 of the second transformer is connected to the node to which S3-S4 is connected.

In addition, one end and the secondary side of the secondary-side first resonance reactance element 1211 are connected to the secondary-side central node (node 'Y') to which the secondary-side first voltage-dividing capacitor C3 and the secondary-side second voltage-dividing capacitor C4 are connected. One end of the second resonant reactance element 1212 is connected.

In addition, the bidirectional resonant DC-DC converter according to an embodiment of the present invention may include a control unit for controlling the primary side switch modules (Q1 ~ Q6) and the secondary side switch modules (S1 ~ S4). The control unit controls the switching elements of the primary side switch modules (Q1 to Q6) and the secondary side switch modules (S1 to S4) to transfer electrical energy in both directions between the first voltage source 10 and the second voltage source 20, but 1 By varying the switching frequency of at least one of the secondary-side switch modules Q1 to Q6 and the secondary-side switch modules S1 to S4, the voltage gain, which is the magnitude of the output voltage relative to the magnitude of the input voltage, may be controlled.

In addition, the control unit, a forward power transfer mode for transferring electrical energy from the first voltage source 10 to the second voltage source 20 and a reverse power transfer for transferring electrical energy from the second voltage source 20 to the first voltage source 10 . In the same mode, the voltage gain can be decreased by increasing the switching frequency, and the voltage gain can be increased by decreasing the switching frequency.

As the resonant reactance elements 1111, 1112, 1211, and 1212, a resonant capacitor, a resonant inductor, or various resonant circuits may be used.

Compared with the previously proposed first type main circuit, the second type main circuit is a main circuit capable of bidirectional power transfer operation in a wider input/output voltage control range, and as shown in FIG. 4A , the first type main circuit proposed above In the circuit, the switching elements Q5 and Q6 are applied instead of the primary-side first and second voltage-dividing capacitors C1, C2 of the primary-side circuit unit 1100, so that 6 switching elements (primary side: Q1 to Q6) are 3 - It is composed of a bridge LLC resonant converter, and the output terminal of the secondary side circuit unit 1200 is the same as the first type main circuit proposed above.

More specifically, two series-connected switching elements Q1-Q2, Q5-Q6, Q3-Q4, respectively, are connected in parallel with three bridge-arms at both ends of the input terminal of the primary side circuit unit 1100, and the secondary side circuit unit (1200) Two bridge-arms in which two series-connected switching elements (S1-S2, S3-S4) are connected in parallel at both ends of the output terminal and two voltage-dividing capacitors connected in series between each bridge-arm (secondary circuit part: C3-C4) ) is connected in parallel with the secondary side voltage divider capacitor.

Between the source and drain of the first and second bridge-arms of the switching elements Q1-Q2 and Q3-Q4 connected to both ends of the input terminal of the primary circuit unit 1100, and between the 1-5 and 1-6 switching elements Q5- The primary side resonant reactance elements 1111 and 1112 (resonant capacitor (Cr1/Cr2) or resonant capacitor and resonant inductor, various resonant filter circuits, etc. can be replaced between the third bridge-arm of Q6), and then used repeatedly. not) and the first and second transformers (T1, T2), primary side primary windings (NP1, NP2) and auxiliary windings (NP11, NP12, NP21, NP22), first and second transformer leakage inductances (LlP1, LlP2, The primary side first and second resonant circuit units including L1S1 and L1S2 (which may be substituted with resonant inductors instead of leakage inductance) are respectively connected, and one end of the primary side first and second resonant reactance elements 1111 and 1112 are connected to the primary side central node (node 'X') to which the 1-5th switching element Q5 and the 1-6th switching element Q6 are connected, respectively.

In addition, the first transformer primary side main winding (NP1) and the primary side first auxiliary winding units (NP11, NP21) are connected to the connection part of the first resonant circuit part of the primary side, and the second transformer of the primary side second resonance circuit part The connection part where the primary side main winding NP2 and the primary side secondary winding parts NP12 and NP22 are connected is connected to each other through a first common connection line, and the other end of the secondary side first resonance reactance 1211 and the The other end 1212 of the secondary-side second resonance reactance is connected to each other through a second common connection line.

By the second common connection line of the secondary side circuit unit 1200, in the forward power transfer mode, a current flows through the primary side first resonant reactance element 1111 and the primary side second resonant reactance element 1112, and the secondary side first No current flows through the resonant reactance element 1211 and the secondary-side second resonant reactance element 1212 .

In addition, by the first common connection line of the primary side circuit unit 1100, in the reverse power transfer mode, a current flows through the secondary side first resonant reactance element 1211 and the secondary side second resonant reactance element 1212, 1 Current does not flow through the primary-side first resonant reactance element 1111, the primary-side first auxiliary winding units NP11 and NP21, the primary-side second resonant reactance element 1112 and the primary-side second auxiliary winding unit NP12, NP22. does not

In addition, the primary windings (NP1, NP2, NP11, NP21, NP12, NP22) of the transformers (T1, T2) of the first and second resonance circuits on the primary side have polarities facing each other (or opposite polarities). The polarity of one of the secondary windings NS1 and NS2 of the transformers T1 and T2 has a different polarity from the polarity of the primary winding transformer.

In other words, the first transformer primary side main winding NP1 and the primary side first auxiliary winding parts NP11 and NP21 are wound to have the same polarity, and the second transformer primary side main winding NP2 and the primary side secondary winding part are wound to have the same polarity. The parts NP12 and NP22 are wound to have the same polarity, and one of the first transformer secondary winding NS1 and the second transformer secondary winding NS2 is wound to have a different polarity.

Therefore, when the forward power transfer mode and the reverse power transfer mode are operated, it operates with a unique bidirectional LLC resonance characteristic.

In addition, when operating in the forward power transfer mode, according to the user's selection, the control unit controls the primary side switch modules Q1 to Q6 so that the primary side circuit unit 1100 operates as a half-bridge forward half-bridge operation mode 1, It is possible to operate in one of the forward half-bridge operation mode 2 or the forward full-bridge operation mode in which the primary circuit unit 1100 operates as a full-bridge. The operation mode may be selected by a user or the control unit may be selected according to the amount of heat generated by each of the switching elements of the primary-side switch modules Q1 to Q6, the degree of stress, the lifespan, the switching operation history, and the like.

In other words, in the bidirectional resonant DC-DC converter having the second type main circuit according to FIG. 4A of the present invention, the forward half-bridge operation according to the switching operation pattern of the primary side switch modules Q1 to Q6 in the forward power transfer mode An operation mode can be selected from among mode 1, forward half-bridge operation mode 2, and forward full-bridge operation mode, and accordingly, bidirectional power transfer in a wider input/output voltage range to the output terminal of the secondary circuit unit 1200 is possible. The operation in the reverse power transfer mode is the same as that of the first type main circuit of the present invention.

4c and 4d, 4f and 4g, 4i and 4j are forward half-bridge operation mode 1, forward direction of the second type main circuit of the bidirectional resonant DC-DC converter according to an embodiment of the present invention, respectively. It is a diagram showing detailed operations of the half-bridge operation mode 2 and the forward full-bridge operation mode.

4e, 4h and 4k show voltage and current waveforms according to the respective operation modes

As shown in FIGS. 4c to 4k, the half-bridge operation mode (Q1 and Q3 are turned on, Q2 and Q4 are turned off continuously, or In a state where Q1 and Q3 are turned off, and Q2 and Q4 are continuously turned on, Q5 and Q6 perform an alternating switching operation at 50% duty, and input voltage (VIN) and 0 voltage is alternately applied so that the resonance currents IP1 and IP2 flow in the primary circuit unit 1100 and transmit power to the secondary circuit unit 1200. Forward half-bridge operation mode 1, or Q5 is turned off, In a state in which Q6 is continuously turned on, Q1/Q3 and Q2/Q4 perform alternating switching operation at 50% duty, and the input voltage (VIN) and 0 voltage are alternately applied to each of the first and second resonance circuits on the primary side. One of the forward half-bridge operation mode 2 in which the resonance currents IP1 and IP2 flows in the primary circuit unit 1100 and transmits power to the secondary circuit unit 1200 can be selected) and full-bridge operation Modes (Q1/Q6/Q3 and Q2/Q5/Q4 perform simultaneous turn-on/turn-off alternating switching operation at 50% duty, and the input voltage (VIN) is applied to each of the first and second resonance circuits on the primary side. It is possible to select an operation mode from among the operation modes in which the resonance currents IP1 and IP2 flow in the primary circuit unit 1100 and provide high gain characteristics to the secondary circuit unit 1200 and transmit power).

Meanwhile, the criterion for selecting the user's operation mode may be the level of the input voltage. When the level of the input voltage is relatively large, the half-bridge operation mode is used, and when the level of the input voltage is relatively small, the full-bridge operation mode. can be selected.

In addition, the criterion for selecting the operation mode may be the magnitude of the output voltage. When the magnitude of the output voltage is relatively small, the half-bridge operation mode is selected, and when the magnitude of the output voltage is relatively large, the full-bridge operation mode is selected. can

At this time, the secondary-side circuit part switch modules S1 to S4 are turned off, so that the load resonance currents IS1 and IS2 are rectified through an anti-parallel diode (it can also operate as a synchronous rectifier). Therefore, when operating in the forward power transfer mode, the input voltage (VIN) or output voltage (Vo) can be adjusted in a wide range depending on the selected operation mode among forward half-bridge operation mode 1, forward half-bridge operation mode 2, and forward full-bridge operation mode. It is possible to control the power in

In addition, the voltage applied to the primary side main windings (NP1, NP2) and the auxiliary windings (NP11, NP12, NP21, NP22) of the transformers (T1, T2) and the secondary windings (NS1, NS2) induced in the secondary side circuit unit 1200 The sum (VS1+VS2) of the secondary-side transformer winding voltage is applied according to the voltage polarity and does not flow through the secondary-side first and second resonant capacitors CR1 and CR2, but the load resonance current (IS1, IS1, When IS2) flows and operates in forward power transfer mode, the LLC resonant converter can operate with unique gain characteristics, and the primary windings (NP1, NP2) and auxiliary windings (NP11, NP12, NP21, NP22) and secondary It is possible to adjust the gain according to the turn-defense of the windings NS1 and NS2.

FIG. 4L is a diagram illustrating voltage gain characteristics in a reverse power transfer mode of a second type main circuit of a bidirectional resonant DC-DC converter according to an embodiment of the present invention.

In addition, FIGS. 4M and 4N are detailed operations of the reverse power transfer mode of the second type main circuit of the bidirectional resonant DC-DC converter according to an embodiment of the present invention, and FIG. 4O is the voltage and current waveforms at this time. it will be shown

As shown in Figs. 4m to 4o, the primary side circuit unit switch modules Q1 to Q6 are turned off, and the rectification operation is performed through an anti-parallel diode, and the secondary side circuit unit 1200 switching elements S1 and S2, S3 and S4 are It operates alternately with a duty of 50%, and S1 and S3, S2 and S4 simultaneously turn-on and turn-off, and are applied to each of the first and second resonant circuits on the secondary side, 1/ _{of the output voltage (V O )} 2 is applied, respectively, and a resonance voltage is applied to the secondary windings NS1 and NS2 of the transformers T1 and T2. At this time, the voltage polarity of the primary side transformer windings (NP1, NP2) is changed by the applied secondary side transformer windings (NS1, NS2) voltage and the sum voltage (N'Vo=VP1+VP2, N'=NP1/NS1=NP2/NS2) is applied, and the sum of the voltages of the auxiliary windings (VNP11+VNP21, VNP12+VNP22) connected to the first and second resonant circuit units on the primary side in the first common connection line is 0, so that the primary side first and second resonant capacitors Cr1 and Cr2 ), the current does not flow through the primary side first auxiliary winding units (NP11, NP21) and the primary side second auxiliary winding units (NP12, NP22), but bypasses the first common connection line and flows through the primary side switching element (Q1/ Q4, Q2/Q3) are rectified to the input terminal through the anti-parallel diode to transmit power in the reverse direction.

Here, the secondary-side first resonant circuit unit has the secondary-side first resonant reactance element 1211, the first transformer secondary-side winding NS1, and the secondary-side first transformer leakage inductance (can be replaced with a resonant inductor instead of a leakage inductance) The secondary-side second resonant circuit unit includes a secondary-side second resonant reactance element 1212 , a second transformer secondary winding NS2 and a secondary-side secondary-side transformer leakage inductance (to be replaced with a resonant inductor instead of a leakage inductance). may be included).

At this time, when the auxiliary windings (NP11-NP21, NP12-NP22) are applied to the transformers (T1, T2) of the first and second resonance circuits of the primary side, when operating in the reverse power transmission mode, unlike when operating in the forward power transmission mode By lowering the voltage delivered to the primary circuit unit 1100 by the turn-defences NP1/NS1 and NP2/NS2 of the transformers T1 and T2, power transmission can be performed, so that the gain can be adjusted.

Also, the secondary-side first and second resonant capacitors CR1 and CR2 and the primary-side first and second resonant capacitors Cr1 and Cr2 are not mutually coupled to each other even during the reverse power transfer mode operation as in the forward power transfer mode operation. and the secondary-side first and second resonance circuit units are parallel-connected, but the primary-side main windings NP1 and NP2 are rectified in series by the voltage polarity of the transformer.

When examining the gain characteristics with reference to FIG. 3G of the equivalent circuit of the first type main circuit described above, it has the unique gain characteristics of the LLC resonant converter even when operating in the reverse power transfer mode, so that gain control can be performed through variable switching frequency control. .

5A is a circuit diagram illustrating a third type main circuit of a bidirectional resonant DC-DC converter according to an embodiment of the present invention, and FIG. 5B is a voltage gain characteristic of the third type main circuit in a forward power transfer mode. did it

Referring to FIG. 5A , the third type main circuit of the bidirectional resonant DC-DC converter according to an embodiment of the present invention includes a primary side circuit unit 1100 and a secondary side circuit unit 1200 . In this case, the primary circuit unit 1100 is connected to the first voltage source 10 , and the secondary circuit unit 1200 is connected to the second voltage source 20 .

In this case, each of the first voltage source 10 and the second voltage source 20 may include at least one of a DC voltage source, a battery, a capacitor, and a load.

Here, the primary-side circuit unit 1100 includes primary-side switch modules Q1 to Q6 including a plurality of switching elements, a primary-side first resonant circuit unit and a primary-side second resonant circuit unit, and the secondary-side circuit unit 1200 includes The secondary-side switch modules S1 to S6 including a plurality of switching elements, the secondary-side windings NS1 and NS2 of each of the first transformer T1 and the second transformer T2, the secondary-side first resonance reactance element 1211 ) and a secondary-side second resonant reactance element 1212 .

At this time, the primary-side switch module (Q1 ~ Q6), the first bridge-arm, 1-3 and 1-4 first bridge-arm to which the 1-1 and 1-2 switching elements (Q1-Q2) are connected in series It includes a second bridge-arm to which the switching elements Q3-Q4 are connected in series, and a third bridge-arm to which the 1-5 and 1-6 switching elements Q5-Q6 are connected in series.

Here, the first to third bridge-arms are all connected in parallel.

In addition, in the primary-side first resonance circuit part, the first transformer primary-side main winding NP1, the primary-side first auxiliary winding parts NP11 and NP21 and the primary-side first resonance reactance element 1111 are connected in series, and the primary side One end of the first resonance circuit unit is connected to the node to which the 1-1 and 1-2 switching elements Q1-Q2 are connected, and the other end is connected to the 1-5 and 1-6 switching elements Q5-Q6. It is connected to the primary-side central node (node 'X').

In addition, in the primary-side second resonance circuit part, the second transformer primary-side main winding NP2, the primary-side second auxiliary winding parts NP12 and NP22 and the primary-side second resonance reactance element 1112 are connected in series, and the primary side One end of the second resonance circuit unit is connected to a node to which the 1-3 and 1-4 switching elements Q3-Q4 are connected, and the other end is connected to the primary side central node (node 'X').

The primary-side first auxiliary winding unit NP11 and NP21 includes a first transformer primary-side first auxiliary winding NP11 and a second transformer primary-side first auxiliary winding NP21, and the primary-side second auxiliary winding unit ( NP12 and NP22 include a second auxiliary winding NP12 on the primary side of the first transformer and a second auxiliary winding NP22 on the primary side of the second transformer.

The secondary-side switch module (S1 to S6) is a fourth bridge-arm to which the 2-1 and 2-2 switching elements (S1-S2) are connected in series-arm, the 2-3 and 2-4 switching elements ( It includes a fifth bridge-arm to which S3-S4 is connected in series and a sixth bridge-arm to which second-5 and 2-6 switching elements S5-S6 are connected in series.

At this time, the fourth to sixth bridge-arms are all connected in parallel.

In addition, one end of the first transformer secondary winding NS1 is connected to the node to which the 2-1 and 2-2 switching elements S1-S2 are connected, and the 2-3 and 2-4 switching elements (S1 - S2) are connected to each other. One end of the secondary winding NS2 of the second transformer is connected to the node to which S3-S4 is connected.

In addition, at the secondary side central node (node 'Y') to which the 2-5 and 2-6 switching elements S5-S6 are connected, one end and the secondary-side second resonance of the secondary-side first resonant reactance element 1211 are connected. One end of the reactance element 1212 is connected.

As the resonant reactance elements 1111, 1112, 1211, and 1212, a resonant capacitor, a resonant inductor, or various resonant circuits may be used.

In addition, the bidirectional resonant DC-DC converter according to an embodiment of the present invention may include a control unit for controlling the primary side switch modules (Q1 ~ Q6) and the secondary side switch modules (S1 ~ S6). The control unit controls the switching elements of the primary side switch module (Q1 ~ Q6) and the secondary side switch module (S1 ~ S6) to transfer electrical energy in both directions between the first voltage source 10 and the second voltage source 20, 1 By varying the switching frequency for at least one of the secondary-side switch modules Q1 to Q6 and the secondary-side switch modules S1 to S6, the voltage gain, which is the magnitude of the output voltage relative to the magnitude of the input voltage, may be controlled.

In addition, the control unit, a forward power transfer mode for transferring electrical energy from the first voltage source 10 to the second voltage source 20 and a reverse power transfer for transferring electrical energy from the second voltage source 20 to the first voltage source 10 . In the same mode, the voltage gain can be decreased by increasing the switching frequency, and the voltage gain can be increased by decreasing the switching frequency.

Compared with the previously proposed second type main circuit, the configuration of the input terminal of the primary side circuit unit 1100 is the same, but the output stage of the secondary side circuit unit 1200 is a switching element ( It is composed of a 3-bridge LLC resonant converter composed of 6 switching elements (secondary side: S1 to S6) to which S5 and S6) are applied. Consists of.

More specifically, two switching elements (primary side: Q1-Q2, Q5-Q6, Q3-Q4, secondary side: S1-S2, S5-S6, S3-S4 , ) are series-connected bridge-arms (Bridge-Legs) are connected in parallel, respectively, so that both the primary side circuit unit 1100 and the secondary side circuit unit 1200 are configured as 3-bridges.

Primary-side resonance between the source and drain of the first and second bridge-arms Q1-Q2 and Q3-Q4 connected in parallel to both ends of the input terminal of the primary circuit unit 1100 and between the third bridge-arm Q5-Q6 Reactance elements 1111 and 1112 or resonant capacitors and resonant inductors, and various resonant circuits may be substituted. (NP1, NP2) and auxiliary windings (NP11, NP12, NP21, NP22), transformer leakage inductance (LIP1, LIP2, LLS1, LLS2, can be replaced with resonant inductance instead of leakage inductance) primary side 1, Each of the second resonant circuit units is connected, and one end of the primary side resonant reactance elements 1111 and 1112 is respectively connected between the central nodes of the third bridge-arms Q5-Q6.

In addition, the secondary side between the source and drain of the fourth and fifth bridge-arms S1-S2 and S3-S4 connected in parallel to both ends of the output terminal of the secondary circuit unit 1200 and between the sixth bridge-arm S5-S6 The first and second resonant circuits are respectively connected, and one end of the first and second resonant reactances 1211 and 1212 on the secondary side is connected between the central node (node 'Y') of the sixth bridge-arm S5-S6. .

In addition, the first transformer primary side main winding (NP1) and the primary side first auxiliary winding units (NP11, NP21) are connected to the connection part of the first resonant circuit part of the primary side, and the second transformer of the primary side second resonance circuit part The connection part where the primary side main winding NP2 and the primary side secondary winding parts NP12 and NP22 are connected is connected to each other through a first common connection line, and the other end of the secondary side first resonance reactance 1211 and the The other end 1212 of the secondary-side second resonance reactance is connected to each other through a second common connection line.

Here, the secondary-side first resonant circuit unit has the secondary-side first resonant reactance element 1211, the first transformer secondary-side winding NS1, and the secondary-side first transformer leakage inductance (can be replaced with a resonant inductor instead of a leakage inductance) The secondary-side second resonant circuit unit includes a secondary-side second resonant reactance element 1212 , a second transformer secondary winding NS2 and a secondary-side secondary-side transformer leakage inductance (to be replaced with a resonant inductor instead of a leakage inductance). may be included).

By the second common connection line of the secondary side circuit unit 1200, in the forward power transfer mode, a current flows through the primary side first resonant reactance element 1111 and the primary side second resonant reactance element 1112, and the secondary side first No current flows through the resonant reactance element 1211 and the secondary-side second resonant reactance element 1212 .

In addition, by the first common connection line of the primary side circuit unit 1100, in the reverse power transfer mode, a current flows through the secondary side first resonant reactance element 1211 and the secondary side second resonant reactance element 1212, 1 Current does not flow through the primary-side first resonant reactance element 1111, the primary-side first auxiliary winding units NP11 and NP21, the primary-side second resonant reactance element 1112 and the primary-side second auxiliary winding unit NP12, NP22. does not

In addition, here, the primary windings (NP1, NP2, NP11, NP21, NP12, NP22) of the transformers (T1, T2) of the first and second resonant circuits of the primary side have polarities facing each other (or opposite polarities). The polarity of one of the secondary windings NS1 and NS2 of the transformers T1 and T2 is different from the polarity of the primary winding transformer.

In other words, the first transformer primary side main winding NP1 and the primary side first auxiliary winding parts NP11 and NP21 are wound to have the same polarity, and the second transformer primary side main winding NP2 and the primary side secondary winding part are wound to have the same polarity. The parts NP12 and NP22 are wound to have the same polarity, and one of the first transformer secondary winding NS1 and the second transformer secondary winding NS2 is wound to have a different polarity.

Therefore, when operating in the forward power transfer mode and the reverse power transfer mode, it is operated with a unique bidirectional LLC resonance characteristic.

In addition, in the bidirectional resonant DC-DC converter having the third type main circuit according to FIG. 5A of the present invention, both the primary side switch modules Q1 to Q6 and the secondary side switch module when operating in the forward power transfer mode and the reverse power transfer mode Half-bridge operation and full-bridge operation are performed according to the switching operation pattern of (S1~S6), enabling bidirectional power transfer in a wider input/output voltage range.

Here, according to the user's selection when operating in the forward power transfer mode, the control unit controls the primary side switch modules Q1 to Q6 and the primary side circuit unit 1100 operates as a half-bridge forward half-bridge operation mode 1, It is possible to operate in one of the forward half-bridge operation mode 2 or the forward full-bridge operation mode in which the primary circuit unit 1100 operates as a full-bridge.

In addition, according to the user's selection when operating in the reverse power transfer mode, the control unit controls the secondary-side switch modules S1 to S6 to operate the secondary-side circuit unit 1200 as a half-bridge reverse half-bridge operation mode 1, The reverse half-bridge operation mode 2 or the secondary-side circuit unit 1200 may operate in one of the reverse full-bridge operation modes in which the full-bridge operates.

The selection of the operation mode in the forward and reverse power transfer modes may be selected by the user or the control unit may be selected according to the amount of heat generated by each of the switching elements of the primary side switch modules Q1 to Q6, the degree of stress, the lifespan, the switching operation history, and the like.

5c and 5d respectively show voltage and current waveforms in forward half-bridge operation mode 1 and forward full-bridge operation mode of the third type main circuit of the bidirectional resonant DC-DC converter according to an embodiment of the present invention; it will be shown

The detailed operation, voltage, and current waveforms in the third type main circuit are the same as in the second type main circuit, so only the voltage and current waveforms of the forward half-bridge operation mode 1 and the forward full-bridge operation mode are shown. .

As shown in Figs. 5c and 5d, the detailed operation in the forward power transfer mode of the third type main circuit of the present invention is similar to the forward operation mode of the second type main circuit. (Q1~Q6) Half-bridge operation according to the switching operation pattern (Q1 and Q3 are turned on, Q2 and Q4 are turned off continuously or Q1 and Q3 are turned off, Q2 and Q4 are turned on continuously In the ON state, Q5 and Q6 perform alternating switching operation at 50% duty, and the input voltage (VIN) and 0 voltage are alternately applied to each of the first and second resonance circuits on the primary side, so that the primary side resonance currents (IP1, IP2) ) flows, and the forward half-bridge operation mode 1 or Q5 that transmits power to the secondary circuit unit 1200 is turned off and Q6 is turned on while Q1/Q3 and Q2/Q4 are 50% duty to alternately switching operation, and the input voltage VIN and 0 voltage are alternately applied to each of the first and second resonant circuit units of the primary side, so that the primary resonant currents IP1 and IP2 flow, and power is supplied to the secondary side circuit unit 1200 You can select one of two forward half-bridge modes of operation to deliver In operation, the input voltage VIN is applied to each of the first and second resonant circuit units of the primary side, the resonance currents IP1 and IP2 flow through the primary side circuit unit 1100, and a high gain characteristic is provided to the secondary side circuit unit 1200. and forward full-bridge mode of operation to deliver power) is possible. At this time, the secondary side switch modules (S1 ~ S6) are turned off, so that the load resonance currents (IS1, IS2) are rectified through the antiparallel diodes (S1/S4, S2/S3).

When operating in forward power transfer mode (forward half-bridge operation mode 1, forward half-bridge operation mode 2 and forward full-bridge operation mode), depending on the operation mode, transformer (T1, T2) primary side main winding (NP1, NP2) And depending on the polarity of the voltage applied to the auxiliary windings (NP11, NP12, NP21, NP22) and the voltages induced to the secondary side (NS1, NS2), the sum (VS1+VS2) of the secondary side transformer winding voltage is applied to the secondary side Instead of flowing through the first and second resonant capacitors CR1 and CR2, the load resonant currents IS1 and IS2 flow in the forward direction through the second common connection line and the antiparallel diode of the switching elements S1/S4, S2/S3. When operating in power transfer mode, the LLC resonant converter can operate with a unique gain characteristic operation. It is possible to adjust the gain according to the turn-defense of the player.

5E is a diagram illustrating a voltage gain characteristic in a reverse power transfer mode of a third type main circuit of a bidirectional resonant DC-DC converter according to an embodiment of the present invention, and FIGS. 5F and 5G are respectively an example of the present invention Voltage and current waveforms in the reverse half-bridge operation mode 1 and the reverse full-bridge operation mode of the third type main circuit of the bidirectional resonant DC-DC converter according to the embodiment are shown.

As shown in FIGS. 5f and 5g, the primary side switch modules Q1 to Q6 are turned off, so the anti-parallel diode operates like a rectifier circuit, and according to the switching operation pattern of the secondary side switch modules S1 to S6, half- In the bridge operation (S1 and S3 are turned off, S2 and S4 are continuously turned on, S5 and S6 are alternately switched at 50% duty, and the output voltage ( Vo) and 0 voltage are alternately applied, secondary side resonance currents (IS1, IS2) flow, and operation mode 1 or S5 that transmits power to the primary side circuit unit 1100 is turned off, and S6 is turned on continuously. In this state, S1/S3 and S2/S4 perform alternating switching operation at 50% duty, and output voltage (Vo) and 0 voltage are alternately applied to each of the first and second resonant circuit units on the secondary side, so that the secondary resonant current (IS1, IS2) flows and one of operation mode 2 in which power is delivered to the primary circuit unit 1100 can be selected) and full-bridge operation (S1/S6/S3 and S2/S5/S4 are simultaneously turned at 50% duty) -On/turn-off alternating switching operation is performed and the output voltage VO is applied to the first and second resonant circuits on the secondary side, so that the resonant currents on the secondary side (IS1, IS2) flow, and a high gain for the primary circuit unit 1100 characteristics and power transfer), so it can operate in a wider input/output voltage control range.

Here, the secondary-side first resonant circuit unit includes a secondary-side first resonant reactance element 1211 , a secondary-side winding NS1 of the first transformer T1, and a second transformer secondary-side first transformer leakage inductance, and the secondary-side second The second resonance circuit unit includes a secondary-side second resonance reactance element 1212 , a secondary-side winding NS2 of the second transformer T2 and a secondary-side secondary transformer leakage inductance.

According to the switching pattern of the secondary side switch modules (S1~S6), the voltage polarity of the primary side transformer windings (NP1, NP2) is changed by the applied secondary side transformer windings (NS1, NS2) voltage during half-bridge and full-bridge operation The sum voltage (N'Vo=VP1+VP2, N'=NP1/NS1=NP2/NS2) is applied, and the auxiliary windings (VNP11+VNP21, VNS12 +VNP22) the sum of the voltages is 0, so the primary side first and second resonant capacitors (Cr1, Cr2), the primary side first auxiliary winding units (NP11, NP21) and the primary side second auxiliary winding units (NP12, NP22) are connected to each other. The current does not flow through it, but flows in a detour through the first common connection line and is rectified to the input terminal through the anti-parallel diode of the primary side switching elements (Q1/Q4, Q2/Q3) to transmit power in the reverse direction. At this time, the auxiliary windings (NPl1/NPl2, NSl1/NSl2) are applied to the transformers (T1, T2) of the first and second resonance circuits of the primary side. By lowering the input terminal voltage of the primary circuit unit 1100 as much as the turn-defense (NP1/NS1, NP2/NS2) of the transformer, power can be transmitted, so that the gain can be adjusted.

6A is a circuit diagram illustrating a 4-1 type main circuit of a bidirectional resonant DC-DC converter according to an embodiment of the present invention, and FIG. 6B is a circuit diagram illustrating a 4-2 type main circuit.

In the main circuits of the 4-1 type and the 4-2 type, the positions of the first and second resonant reactance elements 1211 and 1212 on the secondary side in the main circuits proposed for the first type and the second type are divided into the secondary side voltage dividing capacitors. The basic operating characteristics and bidirectional LLC resonance gain characteristics are the same, except that they are operated by being connected to the parts C3 and C4.

That is, the 4-1 type main circuit is the same as that of the first type main circuit except that one end of the secondary-side first resonant reactance 1211 and one end of the secondary-side second resonant reactance 1212 are the secondary-side central node. (node 'Y') and connected, and the other end is connected to the secondary-side first voltage-dividing capacitor C3 and the secondary-side second voltage-dividing capacitor C4, respectively.

In addition, the 4-2 type main circuit is the same as the second type main circuit except that one end of the secondary-side first resonance reactance 1211 and one end of the secondary-side second resonance reactance 1212 are the secondary-side central node (node 'Y') and connected, and the other end is connected to the secondary-side first voltage-dividing capacitor C3 and the secondary-side second voltage-dividing capacitor C4, respectively.

Since the 4-1 type main circuit operates the same as the first type main circuit and the 4-2 type main circuit operates the same as the second type main circuit, a detailed description thereof will be omitted.

In addition to this, it goes without saying that various bidirectional resonant DC-DC converters can be derived based on the present invention. For example, as shown in FIG. 6C , a switching element may be applied instead of the secondary side voltage divider capacitors C3 and C4 in the 4-2 type main circuit.

7 is a circuit diagram illustrating a fifth type main circuit of a bidirectional resonant DC-DC converter according to an embodiment of the present invention.

The fifth type main circuit of the bidirectional resonant DC-DC converter of the present invention has a (forward or reverse) half-bridge operation mode in the main circuit of the three-bridge configuration of the second type, the third type and the 4-2 type. Switching element (primary side: Q1, Q3, or 2) which is turned on among left and right bridge-arms (primary side: Q1-Q2, Q3-Q4, secondary side: S1-S2, S3-S4) when operating as 1 Instead of the secondary side: S1, S3), a diode (primary side: DQ1, DQ3, or secondary side: DS1, DS3) as shown in FIG. 7 can be used instead.

Alternatively, a diode (primary side: DQ2, DQ4, or secondary side: DS2, DS4) can be used instead of the turned-on switching element (primary side: Q2, Q4, or secondary side: S2, S4) . (not shown)

8 is a table showing main ratings, specifications, and transformer parameters applied in an experiment on the gain characteristics of the bidirectional resonant DC-DC converter of the present invention.

In the present invention, a main circuit having the inherent gain characteristics of an LLC resonant converter during bidirectional operation is proposed, and the output voltage range (Vo: 270Vdc~430Vdc) during bidirectional power transfer operation through variable switching frequency control by receiving an input voltage (Vin) of 750Vdc. The experiment was implemented for

As a representative, it was verified whether wide input/output voltage control is possible by step-up and step-down based on the resonance frequency (fr) through the experimental results on the gain characteristics of the bidirectional resonant DC-DC converter based on the first type main circuit.

Based on the gain characteristics of the first type main circuit of FIGS. 3C and 3H, the switching operation at the resonant frequency fr and the operating characteristics at the switching operation frequency fs1 lower than the resonant frequency fr, than the resonant frequency fr Based on the experiment on the operation characteristics at high switching frequency (fs2), it was shown whether the proposed bidirectional resonant DC-DC converter operates with the unique gain characteristics of LLC.

9 is an experimental waveform during the forward power transfer mode operation for the first type main circuit, and FIG. 10 is a diagram showing the efficiency characteristics at this time.

At this time, when operating in forward power transfer mode, gain control is possible through variable switching frequency control (fs: 250kHz ~ 550kHz), and maximum efficiency under the experimental conditions of input voltage (750VDC), output voltage (350VDC), and output capacity (2kW) This was measured to be 98.81%.

11 is an experimental waveform during the reverse power transfer mode operation for the first type main circuit, and FIG. 12 is a view showing the efficiency characteristics at this time.

When operating in reverse power transfer mode, gain control is possible through variable switching frequency control (fs: 220kHz ~ 550kHz), and maximum efficiency is achieved under the experimental conditions of input voltage (750VDC), output voltage (400VDC), and output capacity (2.5kW). It was measured to be 97.75%.

10: first voltage source
20: second voltage source
1100: primary side circuit part
1200: secondary circuit part
1111: primary side first resonant reactance element
1112: primary side second resonant reactance element
1211: secondary-side first resonant reactance element
1212: secondary-side second resonant reactance element
C1: primary side first voltage dividing capacitor
C2: primary side second voltage divider capacitor
C3: Secondary-side first voltage dividing capacitor
C4: Secondary voltage dividing capacitor
Q1 ~ Q6 : Primary side switch module
S1 ~ S6 : Secondary side switch module
Cr1: primary side first resonant capacitor
Cr2: primary side second resonant capacitor
CR1: Secondary-side first resonant capacitor
CR2: Secondary Resonant Capacitor
T1: first transformer
T2: second transformer
NP1: 1st transformer primary side main winding
NP2: 2nd transformer primary side main winding
NP11: first auxiliary winding on the primary side of the first transformer
NP21: 2nd transformer primary side 1st auxiliary winding
NP12: Second auxiliary winding on the primary side of the first transformer
NP22: Second auxiliary winding on the primary side of the second transformer
NS1: Secondary winding of the first transformer
NS2: secondary winding of the second transformer

Claims (26)

A bidirectional resonant DC-DC converter comprising a primary circuit part connected to a first voltage source and a secondary circuit part connected to a second voltage source,
The primary side circuit unit,
A primary-side switch module including a plurality of switching elements, a primary-side voltage dividing capacitor unit, a primary-side first resonant circuit unit, and a primary-side second resonant circuit unit,
The secondary side circuit unit,
A secondary-side switch module including a plurality of switching elements, a secondary-side voltage dividing capacitor unit, a secondary winding of each of a first transformer and a second transformer, a secondary-side first resonant reactance element and a secondary-side second resonant reactance element,
The primary side first resonant circuit unit includes a first transformer primary side main winding, a primary side first auxiliary winding unit and a primary side first resonant reactance element connected in series, and the primary side second resonant circuit unit is a second transformer primary side The main winding, the secondary secondary winding part on the primary side and the second resonance reactance element on the primary side are connected in series,
The primary-side first resonant reactance element, the primary-side second resonant reactance element, the secondary-side first resonant reactance element, and the secondary-side second resonant reactance element include a resonant capacitor and a resonant inductor,
A node connected to the first transformer primary main winding of the primary side first resonant circuit unit and the primary side first auxiliary winding unit, the second transformer primary main winding and the primary secondary secondary winding of the primary side second resonant circuit unit A bidirectional resonant DC-DC converter, characterized in that the additionally connected nodes are connected through a first common connection line.
According to claim 1,
The primary-side first auxiliary winding portion includes a first auxiliary winding on the primary side of a first transformer and a first auxiliary winding on the primary side of a second transformer, and the second auxiliary winding on the primary side includes a second auxiliary winding and a second auxiliary winding on the primary side of the first transformer. 2 Including a second auxiliary winding on the primary side of the transformer,
The first transformer primary side main winding and the primary side first auxiliary winding unit are wound to have the same polarity, and the second transformer primary side main winding unit and the primary side second auxiliary winding unit are wound to have the same polarity, and the first A bidirectional resonant DC-DC converter, characterized in that the secondary winding of the transformer and one of the secondary winding of the second transformer are wound to have different polarities.
3. The method of claim 2,
In the forward power transfer mode, current flows through the primary-side first resonant reactance element and the primary-side second resonant reactance element, and no current flows through the secondary-side first resonant reactance element and the secondary-side second resonant reactance element. ,
In the reverse power transfer mode, a current flows through the secondary-side first resonant reactance element and the secondary-side second resonant reactance element, and the primary-side first resonant reactance element, the primary-side first auxiliary winding unit, and the primary-side second resonant reactance element 2 A bidirectional resonant DC-DC converter, characterized in that no current flows between the second resonant reactance element and the primary-side second auxiliary winding portion.
4. The method of claim 3,
The primary-side switch module includes a first bridge-arm to which 1-1 and 1-2 switching elements are connected in series and a second bridge-arm to which 1-3 and 1-4 switching elements are connected in series. including,
The primary-side voltage-dividing capacitor unit includes a primary-side first voltage-dividing capacitor and a primary-side second voltage-dividing capacitor connected in series, and is connected in parallel with the first voltage source, the first bridge-arm, and the second bridge-arm;
One end of the primary-side first resonance circuit unit is connected to a node to which the 1-1 and 1-2 switching elements are connected, and the other end is connected to the primary-side first voltage-dividing capacitor and the primary-side second voltage-dividing capacitor. It is connected to the primary side central node,
One end of the primary-side second resonance circuit unit is connected to a node to which the 1-3 and 1-4 switching elements are connected, and the other end is connected to the primary-side central node. .
5. The method of claim 4,
The secondary-side switch module includes a third bridge-arm to which 2-1 and 2-2 switching elements are connected in series, and a fourth bridge-arm to which second-3 and 2-4 switching elements are connected in series. including,
The secondary-side voltage dividing capacitor unit includes a secondary-side first voltage-dividing capacitor and a secondary-side second voltage-dividing capacitor connected in series, and is connected in parallel with the second voltage source, the third bridge-arm, and the fourth bridge-arm;
One end of the secondary winding of the first transformer is connected to a node to which the 2-1 and 2-2 switching elements are connected, and the second to a node to which the 2-3 and 2-4 switching elements are connected. One end of the secondary winding of the transformer is connected,
One end of the secondary-side first resonant reactance element and one end of the secondary-side second resonant reactance element are connected to a secondary-side central node to which the secondary-side first voltage dividing capacitor and the secondary-side second voltage dividing capacitor are connected, and the second A bidirectional resonant DC-DC converter, characterized in that the other end of the secondary-side first resonant reactance element and the other end of the secondary-side second resonant reactance element are connected through a second common connection line.
5. The method of claim 4,
The secondary side switch module includes a third bridge-arm to which 2-1 and 2-2 switching elements are connected in series, and a fourth bridge-arm to which 2-3rd and 2-4th switching elements are connected in series. including,
The secondary-side voltage-dividing capacitor unit includes a secondary-side first voltage-dividing capacitor and a secondary-side second voltage-dividing capacitor,
One end of the secondary-side first resonant reactance and one end of the secondary-side second resonant reactance meet at a secondary-side central node and are connected, and the other end is connected to the secondary-side first voltage divider capacitor and the secondary-side second voltage divider capacitor, respectively, , the other end of the secondary-side first resonant reactance element and the other end of the secondary-side second resonant reactance element are connected through a second common connection line,
One end of the secondary winding of the first transformer is connected to a node to which the 2-1 and 2-2 switching elements are connected, and the second to a node to which the 2-3 and 2-4 switching elements are connected. One end of the secondary winding of the transformer is connected,
The other end of the secondary winding of the first transformer and the other end of the secondary winding of the second transformer meet at the secondary central node and are connected to each other.
A bidirectional resonant DC-DC converter comprising a primary circuit part connected to a first voltage source and a secondary circuit part connected to a second voltage source,
The primary side circuit unit,
A primary-side switch module including a plurality of switching elements, a primary-side first resonant circuit unit and a primary-side second resonant circuit unit,
The secondary side circuit unit,
A secondary-side switch module including a plurality of switching elements, a secondary-side voltage dividing capacitor unit, a secondary winding of each of a first transformer and a second transformer, a secondary-side first resonant reactance element and a secondary-side second resonant reactance element,
The primary side first resonant circuit unit includes a first transformer primary side main winding, a primary side first auxiliary winding unit and a primary side first resonant reactance element connected in series, and the primary side second resonant circuit unit is a second transformer primary side The main winding, the secondary secondary winding part on the primary side and the second resonance reactance element on the primary side are connected in series,
The primary-side first resonant reactance element, the primary-side second resonant reactance element, the secondary-side first resonant reactance element, and the secondary-side second resonant reactance element include a resonant capacitor and a resonant inductor,
A node connected to the first transformer primary main winding of the primary side first resonant circuit unit and the primary side first auxiliary winding unit, the second transformer primary main winding and the primary secondary secondary winding of the primary side second resonant circuit unit A bidirectional resonant DC-DC converter, characterized in that the additionally connected nodes are connected through a first common connection line.
8. The method of claim 7,
The primary-side first auxiliary winding portion includes a first auxiliary winding on the primary side of a first transformer and a first auxiliary winding on the primary side of a second transformer, and the second auxiliary winding on the primary side includes a second auxiliary winding and a second auxiliary winding on the primary side of the first transformer. 2 Including a second auxiliary winding on the primary side of the transformer,
The first transformer primary side main winding and the primary side first auxiliary winding unit are wound to have the same polarity, and the second transformer primary side main winding unit and the primary side second auxiliary winding unit are wound to have the same polarity, and the first A bidirectional resonant DC-DC converter, characterized in that the secondary winding of the transformer and one of the secondary winding of the second transformer are wound to have different polarities.
9. The method of claim 8,
In the forward power transfer mode, current flows through the primary-side first resonant reactance element and the primary-side second resonant reactance element, and no current flows through the secondary-side first resonant reactance element and the secondary-side second resonant reactance element. ,
In the reverse power transfer mode, a current flows through the secondary-side first resonant reactance element and the secondary-side second resonant reactance element, and the primary-side first resonant reactance element, the primary-side first auxiliary winding unit, and the primary-side second resonant reactance element 2 A bidirectional resonant DC-DC converter, characterized in that no current flows between the second resonant reactance element and the primary-side second auxiliary winding portion.
10. The method of claim 9,
The primary side switch module includes a first bridge-arm in which 1-1 and 1-2 switching elements are connected in series, and a second bridge-arm in which 1-3 and 1-4 switching elements are connected in series. and a third bridge-arm to which the 1-5 and 1-6 switching elements are connected in series,
The first to third bridge-arms are all connected in parallel,
One end of the primary-side first resonance circuit unit is connected to a node to which the 1-1 and 1-2 switching elements are connected, and the other end of the first resonant circuit unit is a primary-side center to which the 1-5 and 1-6 switching elements are connected. connected to the node,
One end of the primary-side second resonance circuit unit is connected to a node to which the 1-3 and 1-4 switching elements are connected, and the other end is connected to the primary-side central node. .
11. The method of claim 10,
The secondary side switch module includes a fourth bridge-arm to which 2-1 and 2-2 switching elements are connected in series, and a fifth bridge-arm to which 2-3 and 2-4 switching elements are connected in series. including,
The secondary-side voltage-dividing capacitor unit includes a secondary-side first voltage-dividing capacitor and a secondary-side second voltage-dividing capacitor connected in series, and is connected in parallel with the second voltage source, the fourth bridge-arm, and the fifth bridge-arm;
One end of the secondary winding of the first transformer is connected to a node to which the 2-1 and 2-2 switching elements are connected, and the second to a node to which the 2-3 and 2-4 switching elements are connected. One end of the secondary winding of the transformer is connected,
One end of the secondary-side first resonant reactance element and one end of the secondary-side second resonant reactance element are connected to a secondary-side central node to which the secondary-side first voltage dividing capacitor and the secondary-side second voltage dividing capacitor are connected, and the second A bidirectional resonant DC-DC converter, characterized in that the other end of the secondary-side first resonant reactance element and the other end of the secondary-side second resonant reactance element are connected through a second common connection line.
12. The method of claim 11,
In the forward power transfer mode,
The control unit according to the user's selection,
In one of the operating modes of forward half-bridge operation mode 1, in which the primary side circuitry operates as a half-bridge, forward half-bridge operation mode 2 or forward full-bridge operation mode in which the primary side circuitry operates as a full-bridge. Bidirectional resonant DC-DC converter, characterized in that for controlling the primary side switch module to operate.
13. The method of claim 12,
The bidirectional resonant DC-DC converter, characterized in that the 1-1 switching element and the 1-3 switching element are diodes.
11. The method of claim 10,
The secondary-side switch module includes a fourth bridge-arm to which 2-1 and 2-2 switching elements are connected in series, and a fifth bridge-arm to which 2-3rd and 2-4th switching elements are connected in series. including,
The secondary-side voltage-dividing capacitor unit includes a secondary-side first voltage-dividing capacitor and a secondary-side second voltage-dividing capacitor,
One end of the secondary-side first resonant reactance element and one end of the secondary-side second resonant reactance element meet at a secondary-side central node and are connected, and the other end is connected to the secondary-side first voltage dividing capacitor and the secondary-side second voltage dividing capacitor, respectively. connected, and the other end of the secondary-side first resonant reactance element and the other end of the secondary-side second resonant reactance element are connected through a second common connection line,
One end of the secondary winding of the first transformer is connected to a node to which the 2-1 and 2-2 switching elements are connected, and the second to a node to which the 2-3 and 2-4 switching elements are connected. One end of the secondary winding of the transformer is connected,
The other end of the secondary winding of the first transformer and the other end of the secondary winding of the second transformer meet at the secondary central node and are connected to each other.
15. The method of claim 14,
In the forward power transfer mode,
The control unit according to the user's selection,
In one of the operating modes of forward half-bridge operation mode 1, in which the primary side circuitry operates as a half-bridge, forward half-bridge operation mode 2 or forward full-bridge operation mode in which the primary side circuitry operates as a full-bridge. Bidirectional resonant DC-DC converter, characterized in that for controlling the primary side switch module to operate.
16. The method of claim 15,
The bidirectional resonant DC-DC converter, characterized in that the 1-1 switching element and the 1-3 switching element are diodes.
A bidirectional resonant DC-DC converter comprising a primary circuit part connected to a first voltage source and a secondary circuit part connected to a second voltage source,
The primary side circuit unit,
A primary-side switch module including a plurality of switching elements, a primary-side first resonant circuit unit and a primary-side second resonant circuit unit,
The secondary side circuit unit,
A secondary-side switch module including a plurality of switching elements, a secondary-side winding of each of a first transformer and a second transformer, and a secondary-side first resonant reactance element and a secondary-side second resonant reactance element,
The primary side first resonant circuit unit includes a first transformer primary side main winding, a primary side first auxiliary winding unit and a primary side first resonant reactance element connected in series, and the primary side second resonant circuit unit is a second transformer primary side The main winding, the secondary secondary winding part on the primary side and the second resonance reactance element on the primary side are connected in series,
The primary-side first resonant reactance element, the primary-side second resonant reactance element, the secondary-side first resonant reactance element, and the secondary-side second resonant reactance element include a resonant capacitor and a resonant inductor,
A node connected to the first transformer primary main winding of the primary side first resonant circuit unit and the primary side first auxiliary winding unit, the second transformer primary main winding and the primary secondary secondary winding of the primary side second resonant circuit unit A bidirectional resonant DC-DC converter, characterized in that the additionally connected nodes are connected through a first common connection line.
18. The method of claim 17,
The primary-side first auxiliary winding portion includes a first auxiliary winding on the primary side of a first transformer and a first auxiliary winding on the primary side of a second transformer, and the second auxiliary winding on the primary side includes a second auxiliary winding and a second auxiliary winding on the primary side of the first transformer. 2 Including a second auxiliary winding on the primary side of the transformer,
The first transformer primary side main winding and the primary side first auxiliary winding unit are wound to have the same polarity, and the second transformer primary side main winding unit and the primary side second auxiliary winding unit are wound to have the same polarity, and the first A bidirectional resonant DC-DC converter, characterized in that the secondary winding of the transformer and one of the secondary winding of the second transformer are wound to have different polarities.
19. The method of claim 18,
In the forward power transfer mode, current flows through the primary-side first resonant reactance element and the primary-side second resonant reactance element, and no current flows through the secondary-side first resonant reactance element and the secondary-side second resonant reactance element. ,
In the reverse power transfer mode, a current flows through the secondary-side first resonant reactance element and the secondary-side second resonant reactance element, and the primary-side first resonant reactance element, the primary-side first auxiliary winding unit, and the primary-side second resonant reactance element 2 A bidirectional resonant DC-DC converter, characterized in that no current flows between the second resonant reactance element and the primary-side second auxiliary winding portion.
20. The method of claim 19,
The primary side switch module includes a first bridge-arm in which 1-1 and 1-2 switching elements are connected in series, and a second bridge-arm in which 1-3 and 1-4 switching elements are connected in series. and a third bridge-arm to which the 1-5 and 1-6 switching elements are connected in series,
The first to third bridge-arms are all connected in parallel,
One end of the primary-side first resonance circuit unit is connected to a node to which the 1-1 and 1-2 switching elements are connected, and the other end is a primary-side central node to which the 1-5 and 1-6 switching elements are connected. is connected to
One end of the primary-side second resonance circuit unit is connected to a node to which the 1-3 and 1-4 switching elements are connected, and the other end is connected to the primary-side central node. .
21. The method of claim 20,
The secondary-side switch module includes a fourth bridge-arm to which 2-1 and 2-2 switching elements are connected in series, and a fifth bridge-arm to which second-3 and 2-4 switching elements are connected in series. and a sixth bridge-arm to which the 2-5 and 2-6 switching elements are connected in series,
The fourth to sixth bridge-arms are all connected in parallel,
One end of the secondary winding of the first transformer is connected to a node to which the 2-1 and 2-2 switching elements are connected, and the second to a node to which the 2-3 and 2-4 switching elements are connected. One end of the secondary winding of the transformer is connected,
One end of the secondary-side first resonant reactance element and one end of the secondary-side second resonant reactance element are connected to the secondary-side central node to which the 2-5 and 2-6 switching elements are connected, and The other end and the other end of the second resonant reactance element are connected through a second common connection line.
22. The method of claim 21,
In the forward power transfer mode,
The control unit according to the user's selection,
In one of the operating modes of forward half-bridge operation mode 1, in which the primary side circuitry operates as a half-bridge, forward half-bridge operation mode 2 or forward full-bridge operation mode in which the primary side circuitry operates as a full-bridge. Bidirectional resonant DC-DC converter, characterized in that for controlling the primary side switch module to operate.
23. The method of claim 22,
In the reverse power transfer mode,
The control unit according to the user's selection,
In one of the operation mode of reverse half-bridge operation mode 1, in which the secondary side circuitry operates as a half-bridge, reverse half-bridge operation mode 2 or the reverse full-bridge operation mode in which the secondary side circuitry operates as a full-bridge. Bidirectional resonant DC-DC converter, characterized in that for controlling the secondary side switch module to operate.
24. The method of claim 23,
The bidirectional resonant DC-DC converter, characterized in that the 1-1 switching element, the 1-3 switching element, the 2-1 switching element, and the 2-3rd switching element are diodes.
18. The method of any one of claims 1, 7 and 17, wherein
Bidirectional DC-DC converter, characterized in that the first transformer primary side main winding and the second transformer primary side main winding include leakage inductance.
26. The method of claim 25,
The bidirectional DC-DC converter, characterized in that the first transformer primary-side main winding and the second transformer primary-side main winding include a resonance inductor instead of the leakage inductance.

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