KR102196146B1 - A bidirectional resonant dc-dc converter - Google Patents

Abstract

The present invention relates to a bidirectional resonant DC-DC converter.
The present invention is a bidirectional resonance type DC-DC converter, comprising a primary switch module including a plurality of semiconductor switches, a primary winding of each of a plurality of transformers, a plurality of primary resonance reactance elements, and connected to a first voltage source A primary-side circuit portion that becomes; And a secondary-side switch module including a plurality of semiconductor switches, a plurality of secondary windings magnetically connected to the plurality of transformers, and a secondary-side circuit unit including a plurality of secondary-side resonance reactance elements, and connected to a second voltage source; And a control unit for controlling the primary switch module and the secondary switch module; wherein the control unit controls semiconductor switches of the primary switch module and the secondary switch module to control the first voltage source and the second voltage source. Electrical energy is transferred to each other in both directions, but by varying a switching frequency for at least one of the primary switch module and the secondary switch module, a voltage gain, which is a magnitude of an output voltage relative to an input voltage level, is controlled. It provides a bidirectional resonant DC-DC converter.
According to the present invention, a resonant capacitor is applied to the primary side and the secondary side, and both the forward and reverse operation can operate with the inherent gain characteristics of the LLC resonant converter, and the variable switching frequency control operation enables easy bidirectional power transfer. There is an effect of providing a possible bidirectional resonant DC-DC converter.

Description

Bidirectional resonant DC-DC converter {A BIDIRECTIONAL RESONANT DC-DC CONVERTER}

The present invention relates to a resonant DC-DC converter capable of transmitting power in both directions in two isolated power systems.

The content described in this section merely provides background information on the present embodiment and does not constitute the prior art.

Recently, a two-way DC-DC converter power conversion device is required for applications such as microgrids, energy storage systems (ESS), and electric vehicle charging/discharging systems.

DC/DC converters capable of receiving bidirectional power using an insulated high-frequency transformer have been developed as a method consisting of a voltage source converter and a DC/DC converter capable of receiving bidirectional power in which a voltage source converter and a current source converter are combined [1,2,3]. . However, basically, these power conversion devices have a disadvantage of having a large power conversion loss due to a switching loss due to hard switching. Recently, two-way DC-DC converters with zero voltage switching (ZVS) capable of reducing the size, switching loss and EMI (Electro-Magnetic Interference) have been applied and examined.

1 shows an embodiment of a conventional bidirectional resonant converter. Resonant capacitors (Cr1, Cr2 (or CB1)) are applied to the primary and secondary sides of a resonant converter capable of bidirectional power transfer as shown in Fig.1, depending on the values of the primary and secondary resonant capacitors applied during the forward and reverse power transfer operation. The LLC resonance characteristics as shown in FIG. 2A, the CLLC resonance gain characteristics in which the CCL operation characteristics and LLC resonance characteristics as shown in FIG. 2B are mixed, and the SRC (Series Resonant Converter) resonance gain characteristics as shown in FIG. 2C appear, so that the region and the middle part are lower than the resonance frequency. At this time, the gain slope is inclined to a slope with a value that is lower than the gain at the resonant frequency point and has a resonant gain characteristic different from that of the existing LLC resonant converter gain characteristic, which makes it difficult to transfer power in both directions.

In the case of forward power transfer, there are resonant capacitors on the primary and secondary sides of the resonant converter capable of receiving bidirectional power, and the secondary resonant capacitor is a larger value like the blocking capacitor (CB1) than the applied primary resonant capacitor (Cr1). If it has a capacitance of, since the voltage fluctuation of the secondary capacitor is not large, the voltage gain characteristic, which is the ratio of the input voltage to the output voltage, as in the conventional LLC resonant converter when viewed from the primary side, is characterized as shown in FIG. 2A. That is, if the switching frequency is higher than the resonant frequency, the voltage gain is reduced, and lower than the resonant frequency, the voltage gain is increased.

However, when the capacitance value of the secondary-side resonant capacitor is small, the voltage fluctuation of the secondary-side resonant capacitor (Cr2) increases, and since it is operated in conjunction with the primary-side resonant capacitor (Cr1), CCL resonance characteristics as shown in FIG. And LLC resonance characteristics are mixed with CLLC gain characteristics. Therefore, in the region lower than the normalized resonant frequency (F(1) = fs/fr = 1) and at heavy loads, the gain slope is inclined to a negative slope with a value less than the gain at the resonant frequency point. Unlike the resonant converter gain characteristic, it operates in the hard switching region. In order to have a positive gain slope characteristic so that the gain slope due to such load fluctuations has a greater value than the gain at the resonant frequency point, the magnetizing inductance (Lm) of the applied transformer is greatly reduced to reduce the gain characteristic slope under heavy load conditions. There is a need to improve. However, there is a problem in that a very large magnetizing current Im1 flows according to the very reduced magnetizing inductance Lm1, thereby increasing the conduction loss.

In the case of reverse power transfer, in a resonant converter capable of receiving power in both directions, if the secondary resonant capacitor has a larger capacitance like a blocking capacitor than the primary resonant capacitor, the gain characteristic at this time is as shown in Fig.2c. It has the gain characteristics of the existing SRC (Series Resonant Converter) resonant converter. The primary switching element is in a turn-off state, and power can be transferred to the primary by duty control at a constant switching frequency of the secondary switching element, but switching loss increases due to hard switching when switching by duty control. Has. If a small resonant capacitance (Cr2) value is applied to the secondary resonant capacitor instead of the blocking capacitor (CB1), the voltage fluctuation of the secondary resonant capacitor (Cr2) increases, and it is operated in conjunction with the primary resonant capacitor (Cr1). As shown in Fig. 2b, the CLLC resonance characteristics showing the CCL resonance characteristics and the LLC resonance characteristics appear, and in a region lower than the resonance frequency and under heavy load conditions, unlike the gain characteristics of the existing LLC resonant converter, it is mainly operated in the hard switching region. ·There is a problem that power control becomes difficult in the output voltage range.

The present invention is to solve the problems of the prior art, and provides a bidirectional resonant DC-DC converter capable of gain control by a variable switching frequency when operating a main circuit for forward and reverse power transmission. The main circuit is configured to have the polarity of the transformer applied to the primary and secondary resonant tanks of the bidirectional resonant converter of the present invention and a common connection line that can bypass the load resonant current through the resonant capacitor, and both forward and reverse power transfer operations An object of the present invention is to provide a DC-DC converter capable of receiving bidirectional power having high gain characteristics and high efficiency characteristics by having the inherent gain characteristics of the LLC resonant converter.

The present invention is a bidirectional resonance type DC-DC converter, comprising a primary switch module including a plurality of semiconductor switches, a primary winding of each of a plurality of transformers, a plurality of primary resonance reactance elements, and connected to a first voltage source A primary-side circuit portion that becomes; And a secondary-side switch module including a plurality of semiconductor switches, a plurality of secondary windings magnetically connected to the plurality of transformers, and a secondary-side circuit unit including a plurality of secondary-side resonance reactance elements, and connected to a second voltage source; And a control unit for controlling the primary switch module and the secondary switch module, wherein the control unit controls semiconductor switches of the primary switch module and the secondary switch module to control the first voltage source and the second switch module. Electrical energy is transferred between voltage sources in both directions, but by varying a switching frequency for at least one of the primary switch module and the secondary switch module, a voltage gain, which is a magnitude of an output voltage compared to an input voltage level, is controlled, and the The controller has a forward power transfer mode for transferring electric energy from the first voltage source to the second voltage source and a reverse power transfer mode for transferring electric energy from the second voltage source to the first voltage source, and the forward power transfer mode In the primary-side resonant reactance element, a current flows, and no current flows through the secondary-side resonant reactance element, and in the reverse power transfer mode, a current flows through the secondary-side resonant reactance element, and the primary-side resonant reactance element It provides a bidirectional resonant DC-DC converter characterized in that no current flows.
It is preferable that the control unit decreases the voltage gain by increasing the switching frequency and increases the voltage gain by decreasing the switching frequency, in the same manner in both the forward power transfer and the reverse power transfer mode.

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In the forward power transfer mode, current flows through the primary resonant reactance element, no current flows through the secondary resonant reactance element, and in the reverse power transfer mode, current flows through the secondary resonant reactance element, It is preferable that no current flows through the secondary resonance reactance element.

A primary winding Np1 of a first transformer, which is one of the plurality of transformers, and a secondary winding Ns1, of a first transformer are magnetically connected, and a primary winding of a second transformer, which is another one of the plurality of transformers ( Np2) and the secondary winding Ns2 of the second transformer are magnetically connected, but in the forward power transfer mode, the voltage of the secondary winding of the first transformer and the voltage of the secondary winding of the second transformer are added and applied to the second voltage source. In the reverse power transfer mode, it is preferable that the voltage of the primary winding of the first transformer and the voltage of the primary winding of the second transformer are added and applied to the first voltage source.

It is preferable that the first transformer primary winding and the first transformer secondary winding are wound in the same direction, and the second transformer primary winding and the second transformer secondary winding are wound in opposite directions.

The primary-side switch module includes semiconductor switches 1-1 to 1-4, wherein semiconductor switches 1-1 and 1-2 are connected in series, and semiconductor switches 1-3 and 1-4 are connected in series. It is connected to have a full bridge structure, the node to which the semiconductor switches 1-1 and 1-2 are connected is connected to one end of the primary winding of the first transformer, and the node to which the semiconductor switches 1-3 and 1-4 are connected is the first 2 is connected to one end of the primary winding of the transformer, and the secondary switch module includes semiconductor switches 2-1 to 2-4, wherein the semiconductor switches 2-1 and 2-2 are connected in series, and the second switch module is The semiconductor switches 3 and 2-4 are connected in series to have a full bridge structure, and the nodes to which the semiconductor switches 2-1 and 2-2 are connected are connected to one end of the secondary winding of the first transformer, and the 2-3 and 2 It is preferable that the node to which the -4 semiconductor switch is connected is connected to one end of the secondary winding of the second transformer.

One end of the primary-side resonant reactance element, which is one of the plurality of primary-side resonant reactance elements, and one end of the primary-side secondary resonant reactance element, which is another one of the plurality of primary-side resonant reactance elements, are at a predetermined primary-side center One end of a secondary-side first resonant reactance element that is electrically connected to a node and is one of the plurality of secondary-side resonant reactance elements and a secondary-side second resonant reactance element that is another one of the plurality of secondary-side resonant reactance elements. One end is electrically connected to a predetermined secondary-side central node, the other end of the primary-side first resonant reactance element and the other end of the primary-side second resonant reactance element are electrically connected through a common connection line, and the secondary-side first It is preferable that the other end of the resonant reactance element and the other end of the secondary second resonant reactance element are electrically connected through a common connection line.

The primary-side first resonant reactance element includes a primary-side first resonant capacitor (or may further include a primary-side first resonant inductor in series with the primary-side first resonant capacitor), and the primary-side second resonant reactance The device includes a primary-side second resonant capacitor (or may further include a primary-side second resonant inductor in series with the primary-side second resonant capacitor), and the secondary-side first resonant reactance element is a secondary-side first resonant It includes a capacitor (or may further include a secondary-side first resonant inductor in series with the secondary-side first resonant capacitor), and the secondary-side second resonant reactance element is a secondary-side second resonant capacitor (or secondary-side second resonant capacitor). It is preferable to include a secondary secondary resonant inductor in series with the resonant capacitor).

The other end of the primary-side first resonant reactance element and the other end of the primary-side second resonant reactance element are electrically connected to the other end of the primary winding of the first transformer and the other end of the primary winding of the second transformer, respectively. Do.

The primary-side circuit unit further includes a primary-side first divided capacitor and a primary-side second divided capacitor, and one end and the other end of the primary-side first divided capacitor are connected to the anode of the first voltage source and the primary-side central node, respectively, , It is preferable that one end and the other end of the primary-side second divided capacitor are connected to the primary-side central node and the cathode of the first voltage source, respectively.

The primary-side first resonant reactance element further includes a first notch filter connected in series with the primary-side first resonant capacitor, and the primary-side second resonant reactance element is a second resonant reactance element connected in series with the primary-side second resonant capacitor. It is preferable to further include a two notch filter.

It is preferable that the first notch filter and the second notch filter include an inductor and a capacitor connected in parallel.

The primary-side switch module further includes a 1-5th semiconductor switch connected to a positive electrode of the first voltage source and a primary-side central node, a negative electrode of the first voltage source, and a 1-6th semiconductor switch connected to the primary-side central node. It is preferable to include.

The primary circuit part is between the anode end of the first voltage source and the primary central node, the primary voltage divider capacitor connected in series, the primary secondary winding of the first transformer and the primary secondary secondary of the second transformer. Further comprising a winding, between the negative end of the first voltage source and the primary-side central node, a primary second voltage divider capacitor connected in series, a primary secondary secondary winding of the first transformer, and a primary secondary secondary of the second transformer It further includes 2 auxiliary windings, wherein the primary first auxiliary winding of the first transformer and the primary second auxiliary winding of the first transformer are magnetically connected to the primary winding of the first transformer, and of the second transformer. It is preferable that the primary first auxiliary winding and the primary second auxiliary winding of the second transformer are magnetically connected to the primary winding of the second transformer.

The other end of the primary winding of the first transformer and the other end of the primary winding of the second transformer are electrically connected, and the primary circuit unit further includes a primary first voltage divider capacitor and a primary second voltage divider capacitor, and the first voltage source The primary-side first divided capacitor and the primary-side first resonant reactance element are connected in series between the anode of and the primary-side central node, and between the cathode of the first voltage source and the primary-side central node, 1 It is preferable that the secondary-side second divided capacitor and the primary-side second resonant reactance element are connected in series.

The other end of the secondary-side first resonant reactance element and the other end of the secondary-side second resonant reactance element are electrically connected to the other end of the secondary winding of the first transformer and the other end of the secondary winding of the second transformer, respectively. .

The secondary circuit unit further includes a secondary-side first divided capacitor (C3) and a secondary-side second divided capacitor (C4), and one end and the other end of the secondary-side first divided capacitor are respectively an anode of the second voltage source and the second voltage. It is preferable that it is connected to the secondary center node, and one end and the other end of the secondary second divided capacitor are respectively connected to the secondary center node and the cathode of the second voltage source.

The secondary-side first resonant reactance element further includes a third notch filter connected in series with the secondary-side first resonant capacitor, and the secondary-side second resonant reactance element is a second resonant reactance element connected in series with the secondary-side second resonant capacitor. It is preferable to further include a 4 notch filter.

It is preferable that the third notch filter and the fourth notch filter include an inductor and a capacitor connected in parallel.

The secondary switch module further includes a 2-5 semiconductor switch connected to the anode of the second voltage source and the secondary center node, and a 2-6 semiconductor switch connected to the cathode of the second voltage source and the secondary center node. It is preferable to include.

The secondary circuit part is between the positive end of the second voltage source and the secondary center node, a secondary first voltage divider capacitor connected in series, a secondary first auxiliary winding of the first transformer, and a secondary first auxiliary of the second transformer Further comprising a winding, between the negative end of the second voltage source and the secondary-side central node, the secondary side second voltage divider capacitor connected in series, the secondary side of the second secondary winding (Ns21) of the first transformer, and the second transformer. It further comprises a secondary secondary secondary winding, the secondary secondary secondary winding of the first transformer and the secondary secondary secondary secondary winding Ns21 of the first transformer is magnetically connected to the secondary secondary winding of the first transformer , It is preferable that the second secondary winding of the second transformer and the secondary secondary winding of the second transformer are magnetically connected to the secondary winding of the second transformer.

The other end of the secondary winding of the first transformer and the other end of the secondary winding of the second transformer are electrically connected, and the secondary circuit unit further includes a secondary first divided capacitor and a secondary second divided capacitor, and the second voltage source The secondary-side first divided capacitor and the secondary-side first resonant reactance element are connected in series between the anode of and the secondary-side center node, and between the cathode of the second voltage source and the secondary-side center node, 2 It is preferable that the secondary-side second divided capacitor and the secondary-side second resonant reactance element are connected in series.

Hereinafter, the present invention will be described in more detail through examples, but the description of these examples is for illustrative purposes only and the present invention is not limited by the description of these examples.

As described above, according to the present invention, a resonant capacitor is applied to the primary side and the secondary side, and in both forward and reverse operation, the LLC resonant converter can operate with inherent gain characteristics, and it is easy by the variable switching frequency control operation. There is an effect of providing a bidirectional resonant DC-DC converter capable of transferring power in both directions.

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 CLLC and SRC gain characteristics of a conventional bidirectional resonant DC-DC converter.
FIG. 3A shows an embodiment in which a first type of primary circuit portion and a first type of secondary circuit portion of the proposed bidirectional resonant DC-DC converter of the present invention are combined.
3B shows an equivalent circuit in the forward power transfer operation of the first type of the proposed bidirectional resonant DC-DC converter of the present invention.
3C shows voltage gain characteristics of the proposed bidirectional resonant DC-DC converter of the present invention in a forward power transfer operation of the first type.
3D shows an operation mode of a first type of forward power transmission of the proposed bidirectional resonant DC-DC converter of the present invention.
3E is a diagram showing voltage and current waveforms during a forward power transfer operation of the first type of the proposed bidirectional resonant DC-DC converter of the present invention.
FIG. 3F shows an equivalent circuit in the reverse power transfer operation of the first type of the proposed bidirectional resonant DC-DC converter of the present invention.
3G is a diagram illustrating a voltage gain characteristic of a first type of reverse power transfer operation of the proposed bidirectional resonant DC-DC converter of the present invention.
Figure 3h is a primary side resonance tank voltage (VPT1) / resonance current (IP1) and secondary side first transformer secondary winding voltage (VST1) / load resonance when gain control according to the variable switching frequency control during the forward power transfer operation of Figure 3a. It shows the current (Is) experimental operation waveform.
4A and 4B each show an embodiment of a second type of primary circuit portion and secondary circuit portion of the proposed bidirectional resonant DC-DC converter of the present invention.
4C shows gain characteristics during a forward power transfer operation in the bidirectional LLC resonant converter of FIGS. 4A and 4B.
4D shows a switching pattern, each sub-voltage, and current waveforms during a full-bridge (FB) operation during a forward power transfer operation in a bidirectional LLC resonant converter.
4E is a diagram showing a switching pattern, each sub-voltage, and current waveforms during a half-bridge (HB) operation during a forward power transfer operation in a bidirectional LLC resonant converter.
FIG. 4F shows gain characteristics during reverse power transfer operation in the bidirectional LLC resonant converter of FIGS. 4A/ 4B.
4G shows a switching pattern, each sub-voltage, and current waveforms during a full-bridge (FB) operation during a reverse power transfer operation in a bidirectional LLC resonant converter.
4H shows a switching pattern, each sub-voltage, and current waveforms during a half-bridge (HB) operation during a reverse power transfer operation in a bidirectional LLC resonant converter.
Figure 4i shows an embodiment of a half-bridge bidirectional LLC resonant converter.
Figure 4j shows another embodiment of the half-bridge bi-directional LLC resonant converter.
5A and 5B respectively show an embodiment of a third type of primary circuit portion and secondary circuit portion of the proposed bidirectional resonant DC-DC converter of the present invention.
6A, 6B, 6C, and 6D each show an embodiment of a fourth type of primary circuit part of the proposed bidirectional resonant DC-DC converter of the present invention; Embodiment of the secondary side circuit part; Forward voltage gain characteristics; And reverse voltage gain characteristics.
7A and 7B each shows an embodiment of a fifth type of primary circuit portion and secondary circuit portion of the proposed bidirectional resonant DC-DC converter of the present invention.

Objects, features and advantages of the present invention described above will become more apparent through the following embodiments in connection with the accompanying drawings. The following specific structure or functional descriptions are exemplified only for the purpose of describing embodiments according to the concept of the present invention, and embodiments according to the concept of the present invention may be implemented in various forms and described in the specification or application. It should not be construed as being limited to the examples. Since embodiments according to the concept of the present invention can be modified in various ways and have various forms, specific embodiments are illustrated in the drawings and will be 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 form of disclosure, it should be understood to include all changes, 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 terms are only for the purpose of distinguishing one component from other components, for example, without departing from the scope of rights according to the concept of the present invention, the first component can be named as the second component, and is similar. Thus, the second component may also be referred to as a first component. When a certain component is connected to or is referred to as being connected to another component, it should be understood that it is directly connected to or may be connected to the other component, but other components may exist in the middle. On the other hand, when a component is directly connected to another component or is referred to as being directly connected, it should be understood that there is no other component in the middle. Other expressions for explaining the relationship between the constituent elements, ie, between and immediately between or adjacent to and directly adjacent to, should be interpreted as well. Terms used in the present specification are used only to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present specification, terms such as include or have are intended to designate the existence of a set feature, number, step, action, component, part, or combination thereof, and one or more other features or numbers, steps, actions, It is to be understood that the possibility of the presence or addition of components, parts or combinations thereof is not preliminarily excluded. Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in this specification. Does not. Hereinafter, the present invention will be described in detail by describing a preferred embodiment of the present invention with reference to the accompanying drawings. The same reference numerals in each drawing indicate the same member.

FIG. 3A shows an embodiment in which a first type of primary circuit portion and a first type of secondary circuit portion of the proposed bidirectional resonant DC-DC converter of the present invention are combined.

The present invention is a bidirectional resonance type DC-DC converter, comprising a primary switch module including a plurality of semiconductor switches, a primary winding of each of a plurality of transformers, a plurality of primary resonance reactance elements, and a first voltage source (10 ) Connected to the primary side circuit unit 1100, and a secondary side switch module including a plurality of semiconductor switches, a plurality of secondary windings respectively magnetically connected to the plurality of transformers, and a plurality of secondary side resonance reactance elements, A secondary circuit part 1200 connected to the second voltage source 20, and a control unit for controlling the primary switch module and the secondary switch module, wherein the control unit includes the primary switch module and the secondary switch By controlling the semiconductor switches of the module, electric energy is transferred in both directions between the first voltage source 10 and the second voltage source 20, but the switching frequency of at least one of the primary switch module and the secondary switch module is adjusted. By varying, the voltage gain, which is the magnitude of the output voltage compared to the magnitude of the input voltage, can be controlled.

The control unit, in the same manner in a forward power transfer mode transferring electric energy from the first voltage source to the second voltage source and a reverse power transfer mode transferring electric energy from the second voltage source to the first voltage source, the switching frequency It may be characterized in that the voltage gain is decreased by increasing the and the voltage gain is increased by decreasing the switching frequency.

In the forward power transfer mode, current flows through the primary resonant reactance element, no current flows through the secondary resonant reactance element, and in the reverse power transfer mode, current flows through the secondary resonant reactance element, It may be characterized in that no current flows through the secondary resonance reactance element.

One of the plurality of transformers, the primary winding Np1 of the first transformer T1 and the secondary winding Ns1 of the first transformer T1 are magnetically connected, and another one of the plurality of transformers The primary winding Np2 of the second transformer and the secondary winding Ns2 of the second transformer are magnetically connected. In the forward power transfer mode, the voltage of the secondary winding Ns1 of the first transformer and the 2 The voltage of the secondary winding Ns2 of the transformer is added and applied to the second voltage source 20, and in the reverse power transfer mode, the voltage of the primary winding Np1 of the first transformer and the primary winding of the second transformer ( A voltage of Np1) may be added and applied to the first voltage source 10.

The first transformer primary winding Np1 and the first transformer secondary winding Ns1 are wound in the same direction, and the second transformer primary winding Np2 and the second transformer secondary winding Ns2 ) May be characterized in that the windings are wound in opposite directions.

The primary-side switch module includes semiconductor switches 1-1 to 1-4 (Q1 to Q4), wherein the semiconductor switches 1-1 and 1-2 are connected in series, and the 1- 3 and 1-4 semiconductor switches Q3 and Q4 are connected in series to have a full bridge structure, and the nodes 1-1 and 1-2 semiconductor switches are connected to one end of the primary winding Np1 of the first transformer A node connected to the semiconductor switches 1-3 and 1-4 is connected to one end of the primary winding Np2 of the second transformer, and the secondary switch module includes the semiconductor switches 2-1 to 2-4 (S1 to S4), but the 2-1 and 2-2 semiconductor switches (S1, S2) are connected in series, and the 2-3 and 2-4 semiconductor switches (S3, S4) are connected in series. The node has a full bridge structure, and the nodes 2-1 and 2-2 semiconductor switches are connected to one end of the secondary winding Ns1 of the first transformer, and the nodes 2-3 and 2-4 semiconductor switches are connected to each other. The second transformer may be connected to one end of the secondary winding Ns2.

One end of the primary-side first resonant reactance element 1111, which is one of the plurality of primary-side resonant reactance elements, and one end of the primary-side second resonant reactance element 1112, which is another one of the plurality of primary-side resonant reactance elements One end of the secondary-side first resonant reactance element 1211 which is electrically connected to the predetermined primary-side central node and is any one of the plurality of secondary-side resonant reactance elements, and another one of the plurality of secondary-side resonant reactance elements One end of the secondary-side second resonant reactance element 1212 is electrically connected to a predetermined secondary-side central node, the other end of the primary-side first resonant reactance element 1111 and the primary-side second resonant reactance element 1112 The other end of) is electrically connected through a common connection line, and the other end of the secondary-side first resonant reactance element 1211 and the other end of the secondary-side second resonant reactance element 1212 are electrically connected through a common connection line. You can do it.

In more detail, as shown in FIG. 3A, two switching elements (primary side: Q1-Q2, Q3-Q4, secondary side: S1-S2, S3-S4) are provided on each of the input stage primary side and the output stage secondary side. A bridge circuit connected in series and two capacitors (primary side: C1-C2, secondary side: C3-C4) are connected in series, and a bridge circuit (primary side: Q1-Q2, Q3-Q4, secondary side: S1-S2) , S3-S4) and series connection capacitors (primary side: C1-C2, secondary side: C3-C4) are connected in parallel, and each bridge switching device (primary side: Q1-Q2, Q3-Q4, secondary side : A resonant capacitor (primary side: Cr1/Cr2, secondary side) between the source and drain of S1-S2, S3-S4) and the serial connection capacitor (primary side: C1-C2, secondary side: C3-C4) center terminal : CR1/CR2) and a resonant tank composed of a transformer (T1, T2, transformer leakage inductance (LlP1, LlP2, LlS1, LlS2) instead of a separate resonant inductor can be applied) are connected respectively, and the resonant capacitor of each resonant tank (Primary side: Cr1/Cr2, secondary side: CR1/CR2) is connected between the center terminals of a series-connected voltage divider capacitor (primary side: C1-C2, secondary side: C3-C4), and each resonance capacitor (primary side: Cr1 /Cr2, secondary side: The other end of CR1/CR2) is connected with a common tied line. And the primary side transformer (T1, T2) windings (NP1, NP2) of the resonance tank look at each other and have polarity, and the secondary side main circuit is symmetrical with the primary side main circuit composition based on the output stage, but one transformer of the secondary side tank The polarity of is connected with a polarity different from that of the primary transformer winding.

As described above, in the case of a conventional bidirectional CLLC resonant converter, since the primary and secondary resonant capacitors are coupled, it is difficult to control gain in a frequency region lower than the resonant frequency, which implies limitations in the control operation of the variable switching frequency. On the other hand, in the present invention, even if the resonant capacitor is applied to the primary and secondary sides, it can operate with the inherent gain characteristics of the LLC resonant converter during forward and reverse operation, enabling easy bi-directional power transfer by the variable switching frequency control operation. It works.

FIG. 3B shows an equivalent circuit during a first type of forward power transfer operation, and FIG. 3C shows a voltage gain characteristic during a forward power transfer operation. In the forward power transfer operation, the primary side main circuit operation operates alternately with switching elements Q1 and Q2, Q3 and Q4 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 (primary voltage source) is applied to each resonance tank, the resonance voltage is applied to the primary windings (NP1, NP2) of the transformers (T1, T2), and the resonance currents (IP1, IP2) flow. At this time, the secondary main circuit switching elements (S1, S2, S3, S4) are turned off, so they are rectified only through the reverse-parallel diode of the switching element. In addition, the voltage polarity of the applied secondary transformer windings (NS1, NS2) is connected in series, so that the sum voltage (VS1+VS2) is applied, and the secondary side resonant capacitors (CR1, CR2) are bypassed and flowed through a common connection line. It is rectified to the output stage through the reverse-parallel diode of the secondary-side switching device to deliver forward power. Therefore, in the forward power transfer operation, the primary resonant capacitors (Cr1, Cr2) and the secondary resonant capacitors (CR1, CR2) operate without being coupled to each other, and the primary resonant tank circuit is connected in parallel, but due to the voltage polarity of the transformer. Since the secondary winding is operated in series connection, if the gain characteristic is calculated using the superposition principle based on the equivalent circuit shown in FIG. 3B, it has a gain characteristic unique to the LLC resonant converter, and the gain can be controlled through the variable switching frequency control.

3D and 3E respectively show the operation mode and voltage and current waveforms of the proposed bidirectional resonant DC-DC converter of the present invention during forward power transmission of the first type. The detailed operation of forward power transfer of the first type of LLC resonant converter capable of receiving and receiving bidirectional power will be described by dividing into six sections as shown in FIGS. 3D and 3E.

(1) t0-t1 section

During this period, the primary switching devices Q1 and Q3 are turned on under the ZVS (Zero Voltage Switching) condition, and 1/2 of the input voltage (Vin) is applied to each resonance tank circuit on the primary side. The resonance voltage is applied to the primary windings (NP1, NP2) of the transformer in the resonance tank, and the resonance currents (IP1, IP2) branch and flow in parallel, and the load resonance currents (IS1, IS2) are transferred to the secondary side. At this time, the total voltage (VS1+VS2) is applied to the load terminal by the voltage polarity of the secondary windings (NS1, NS2) of the transformer (T1, T2), so that the load resonance current (IS=IS1=IS2) becomes the secondary resonance capacitor (CR1, NS2). Rather than CR2), it continues to flow through the bypassing common connection line.

.

(2) t1-t2 section

At t1, the primary juice switching elements Q1 and Q3 are turned on continuously and operate in a frequency range lower than the resonant frequency.Therefore, the resonant current ends and only the magnetizing currents (ImP1, ImP2) flow, so the load resonant current (IS1) on the secondary side is =IS2=0) does not flow and the voltage of the secondary capacitor (C3+C4) is only discharged through the load.

(3) t2-t3 section

When the switching elements of Q1 and Q3 are turned off at the time t2, the parasitic capacitance (Cp) of Q1 and Q3 is charged during the dead time by the transformer magnetizing current (ImP1, ImP2) and charged to the input voltage (Vin), The voltage of the parasitic capacitance (Cp) of Q2 and Q4 starts discharging and discharges to 0 voltage, and then turns on at the point where the current flows through the antiparallel diodes of Q2 and Q4, the zero voltage switching is operated and this mode ends. At this time, the voltage polarity applied to the primary side transformers (T1, T2) is changed during the dead time, so the voltage polarity of the secondary side windings (NS1, NS2) of the transformer is also changed, so that the load resonance current (IS1=IS2) becomes the secondary resonance capacitor (CR1, T2). It starts to flow through the common connection line that bypasses CR2), and the sum voltage (VS1+VS2) of the secondary winding of the transformer is applied to the output load.

(4) t3-t4 section

In the t3-t4 section, at the time t3, the primary juice switching elements Q2 and Q4 are turned on at zero voltage, and 1/2 of the input voltage Vin is applied to each resonant tank, and the resonant current in parallel to each resonant tank. A (IP1, IP2) flows, and at this time, the voltage by the turn-ratio of the transformer and the gain of the resonance circuit is applied, and the secondary rectifier is the sum voltage (VS1+VS2) according to the voltage polarity of the windings of each transformer (T1, T2). As this output load is applied, the load resonance current (IS=IS1=IS2) starts to flow continuously through the common connection line that bypasses the secondary resonance capacitors (CR1, CR2).

(5) t4-t5. t5-t6 section

Since the remaining sections (t4-t5 and t5-t6) operate repeatedly with the previous half-cycle, the description of the operation will be omitted.

FIG. 3F is an equivalent circuit in the reverse power transfer operation of the first type of the proposed bidirectional resonant DC-DC converter of the present invention, and FIG. 3G shows the voltage gain characteristics during the reverse power transfer operation of the first type.

In reverse power transfer operation, the primary main circuit switching elements (Q1, Q2, Q3, Q4) are turned off, rectified through the reverse parallel diode of the primary main circuit switching element, and the secondary switching elements S1 and S2 , S3 and S4 have a duty of 50% and alternately switch operation, and S1 and S3, S2 and S4 simultaneously turn-on and turn-off operation, and output terminal voltage (secondary voltage source) to the secondary resonance tank /2 is applied, resonance currents (IS1, IS2) branch and flow in parallel to each resonance tank, and a resonance voltage is applied to the secondary terminals of the transformers (T1, T2). At this time, the voltage polarity of the primary transformer windings (NP1, NP2) is changed according to the voltage polarity of the applied secondary transformer windings (NS1, NS2), and the total voltage (VP1 + VP2) is applied by connecting in series, and each primary resonant capacitor ( Rather than Cr1, Cr2), the load resonance current (IP1=IP2) flows bypassing through the common connection line, rectifying it to the input terminal through the reverse-parallel diode of the primary switching element and transferring power in the reverse direction.

Therefore, even during the reverse power transfer operation as in the forward power transfer operation, the secondary resonant capacitors (CR1, CR2) and the primary resonant capacitors (Cr1, Cr2) operate without being coupled to each other, and the secondary resonant tank circuit operates in parallel. However, since the primary winding is connected in series due to the voltage polarity of the transformer, the gain characteristic is obtained using the equivalent circuit of Fig. 3f. As shown in Fig. 3G, the LLC resonant converter has the inherent gain characteristic even during the reverse power transfer operation. Gain control can be performed through variable switching frequency control.

In order to check the operating characteristics through the experimental example during the forward power transfer operation of FIG. 3A, the output voltage control range from the first voltage source 10 voltage 750Vdc condition to the second voltage source 20 is 300Vdc/2.5KW, 350Vdc/ Fig. 3h shows an operation experiment waveform in which gain is controlled through variable control of switching frequency up to 2.5kW and 430Vdc/2.5kW.

In Fig. 3a, it can be seen that even if the resonant capacitors on the primary side (Cr1, Cr2) and the resonant capacitors (CR1, CR2) are applied to the secondary side, they are not mutually coupled and operate with the LLC resonance gain characteristics as suggested in the present invention. have.

Since the operation mode, voltage, current flow chart, and operation characteristics of the reverse power transfer mode are symmetrically the same as the operation of the forward power transfer mode, a description is omitted.

4 to 7 show the 2nd to 5th types of primary and secondary circuits. Although FIG. 3A shows only an embodiment consisting of a first type primary-side circuit part and a first type secondary-side circuit part, the present invention relates to any one of the first to fifth types of primary circuit parts and the first to fifth types of 2 All embodiments in which any one of the secondary circuit units is combined are included. That is, as another embodiment, a first type of primary circuit unit and a second type of secondary circuit unit may be combined.

The primary-side first resonant reactance element 1111 includes a primary-side first resonant capacitor Cr1, and the primary-side second resonant reactance element 1112 includes a primary-side second resonant capacitor Cr2, The secondary-side first resonant reactance element 1211 includes a secondary-side first resonant capacitor CR1, and the secondary-side second resonant reactance element 1212 includes a secondary-side second resonant capacitor CR2. It can be characterized.

The other end of the primary-side first resonant reactance element 1111 and the other end of the primary-side second resonant reactance element 1112 are the other end of the primary winding Np1 of the first transformer and the primary winding of the second transformer. It can be characterized by being electrically connected to the other end of (Np2).

The primary-side circuit unit 1100 further includes a primary-side first divided capacitor C1 and a primary-side second divided capacitor C2, and one end and the other end of the primary-side first divided capacitor C1 are each of the first It is connected to the anode of the voltage source 10 and the primary central node, and one end and the other end of the primary second divided capacitor C2 are respectively connected to the primary central node and the cathode of the first voltage source 10. It can be characterized.

6, the primary-side first resonant reactance element 1111 further includes a first notch filter connected in series with the primary-side first resonant capacitor Cr1, and the primary-side second resonant reactance The element 1112 may further include a second notch filter connected in series with the primary second resonant capacitor Cr2.

The first notch filter and the second notch filter may include an inductor and a capacitor connected in parallel.

6C and 6D each show a forward voltage gain characteristic and a reverse voltage gain characteristic of a fourth type of the proposed bidirectional resonant DC-DC converter of the present invention. Due to this characteristic, the gain characteristic can be lowered in the control range above the resonant frequency, so that a wide gain control range can be secured in a narrower frequency control range.

The primary-side switch module may include a positive electrode of the first voltage source 10 and a 1-5 semiconductor switch Q5 connected to the primary-side central node, a negative electrode of the first voltage source 10 and the primary-side central node. It may be characterized in that it further comprises a connected 1-6th semiconductor switch (Q6).

Due to this feature, as shown in Figs. 4A and 4B, a three-bridge circuit and a three-bridge circuit composed of six switching elements (primary side: Q1 to Q6, secondary side: S1 to S6) respectively on the primary and secondary sides are connected in common. The resonant capacitor is incorporated to have the effect of bidirectional power transfer operation in a wider input/output voltage control range.

4C illustrates voltage gain characteristics during the forward power transfer operation of FIGS. 4A/ 4B. As shown in Fig. 4d, in the forward power transfer operation, the primary main circuit operation operates alternately with switching elements Q1 and Q2, Q3 and Q4, and Q5 and Q6 with a duty of 50%, and Q1/Q3 and Q6, Q2/ Q4 and Q5 simultaneously turn-on and turn-off, and the input voltage (primary voltage source) is applied to each resonance tank like a full-bridge, and the resonance voltage is applied to the primary windings (NP1, NP2) of the transformers (T1, T2). Is applied and resonance currents (IP1, IP2) flow. At this time, the secondary main circuit switching elements (S1, S2, S3, S4, S5, S6) are turned off and are rectified only through the reverse-parallel diode of the switching element. In addition, the voltage polarity of the applied secondary transformer windings (NS1, NS2) is connected in series, so that the sum voltage (VS1+VS2) is applied, does not flow through the secondary resonant capacitors (CR1, CR2), and connects a common tied connection line. As it bypasses and flows through, it is rectified to the output stage through the reverse-parallel diode of the secondary switching device to deliver forward power. Therefore, in the forward power transfer operation, the primary resonant capacitors (Cr1, Cr2) and the secondary resonant capacitors (CR1, CR2) operate without being coupled to each other, and the primary resonant tank circuit is connected in parallel, but due to the voltage polarity of the transformer. Since the secondary winding is operated in series, it has FB Gain Characteristics inherent to the full-bridge LLC resonant converter shown in Fig. 4c, so that gain can be controlled through variable switching frequency control. .

FIG. 4D is a diagram showing the operating voltage and current waveforms of the second type of full-bridge (FB) bidirectional resonant converter of the proposed bidirectional resonant DC-DC converter of the present invention when forward power is transmitted.

In addition, according to the switching pattern shown in Fig. 4e, it was shown that a half-bridge (HB) bidirectional LLC resonant converter can perform forward power transfer operation. At this time, in the forward power transfer operation, the primary side main circuit operation is in a state in which switching devices Q1 and Q3 are turned off, and Q2 and Q4 are turned on (or switching devices Q1 and Q3 are turned on, and Q2 and Q4). Can be operated even when turned off), Q5 and Q6 operate alternately with a duty of 50%, and 1/2 of the input voltage (primary voltage source) is applied to each resonance tank like a half-bridge Then, the resonance voltage is applied to the primary windings (NP1, NP2) of the transformers (T1, T2) and the resonance currents (IP1, IP2) flow. At this time, the secondary main circuit switching elements (S1, S2, S3, S4, S5, S6) are turned off and are rectified only through the reverse-parallel diode of the switching element. At this time, the voltage polarity of the applied secondary transformer windings (NS1, NS2) is connected in series, so that the sum voltage (VS1 + VS2) is applied, does not flow through the secondary resonant capacitors (CR1, CR2), and connects a common connection line. As it bypasses and flows through, it is rectified to the output stage through the reverse-parallel diode of the secondary switching device to deliver forward power. Therefore, since the half-bridge (HB) LLC resonant converter shown in FIG. 4C has HB Gain Charcteristics, it is possible to control gain through variable switching frequency control.

4F shows the voltage gain characteristics of the proposed bidirectional resonant DC-DC converter of the present invention during a reverse power transfer operation of the second type.

As shown in Fig. 4g, during the reverse power transfer operation, the primary main circuit switching elements (Q1, Q2, Q3, Q4, Q5, Q6) are turned off, and through the reverse-parallel diode of the primary main circuit switching element. Rectified operation is performed, and the secondary switching elements S1 and S2, S3 and S4, S5 and S6 are alternately switched with a duty of 50%, and S1/S3 and S6, S2/S4 and S5 are simultaneously turned on and turned. -Off operation, the output terminal voltage (secondary voltage source) is applied to the secondary resonance tank, the resonance currents (IS1, IS2) branch and flow in parallel to each resonance tank, and the resonance voltage at the secondary terminals of the transformers (T1, T2) Is applied. At this time, the voltage polarity of the primary transformer windings (NP1, NP2) is changed according to the voltage polarity of the applied secondary transformer windings (NS1, NS2), and the total voltage (VP1 + VP2) is applied by connecting in series, and each primary resonant capacitor ( The load resonance current (IP1=IP2) does not flow through Cr1, Cr2), and flows bypassing through the common connection line, rectifying it to the input terminal through the reverse-parallel diode of the primary-side switching element and transmitting reverse power.

Therefore, even during the reverse power transfer operation of FIG. 4F, since the full-bridge (FB) LLC resonant converter has FB Gain Characteristics, the gain can be controlled through the variable switching frequency control.

Figure 4h shows the half-bridge reverse power transfer operation voltage and current waveform of the second type of the proposed bidirectional resonant DC-DC converter of the present invention, according to the switching operation pattern, the half-bridge (HB) bidirectional resonant converter Indicated that it can operate as. In the reverse power transfer operation at this time, the secondary side main circuit operation is in a state in which the switching elements S1 and S3 are turned off, and S2 and S4 are turned on (or the switching elements S1 and S3 are turned on, and S2 and S4). Can be operated even when turned off), S5 and S6 operate alternately with a duty of 50%, and half of the output voltage (secondary voltage source) to each secondary resonance tank like a half-bridge Is applied, a resonance voltage is applied to the secondary windings (NS1, NS2) of the transformers (T1, T2), and the resonance currents (IS1, IS2) flow. At this time, the primary main circuit switching elements (Q1, Q2, Q3, Q4, Q5, Q6) are turned off, so they are rectified only through the reverse-parallel diode of the switching element. In addition, the voltage polarity of each applied primary transformer winding (NP1, NP2) is connected in series, so that the sum voltage (VP1 + VP2) is applied, does not flow through the primary resonant capacitors (Cr1, Cr2), and connects a common connection line. As it bypasses and flows through, it is rectified to the input terminal through the reverse-parallel diode of the primary-side switching device to deliver reverse power. Therefore, the secondary resonance tank circuit operates in parallel, but the primary winding is connected in series due to the voltage polarity of the transformer, so it has the HB Gain Characteristics inherent to the half-bridge (HB) LLC resonant converter shown in Fig. 4f. So, gain control can be performed through variable switching frequency control.

4I and 4J show that in the full-bridge bidirectional resonant converter of FIGS. 4A/4B, the primary switching elements Q1/Q3 (or Q2/Q4) and the secondary switching elements S1/S3 (or S2/S4) are replaced with diodes. Except for the loss, the half-bridge (HB) bidirectional power transfer switching operation pattern and operation waveform are the same. Detailed description is omitted.

As shown in FIG. 7, the primary circuit unit 1100 includes a primary first voltage divider capacitor C1 connected in series between the positive end of the first voltage source 10 and the primary central node, and a first transformer. The primary side of the first auxiliary winding (Np11) and the primary side of the second transformer further comprises a first auxiliary winding (Np21), between the negative end of the first voltage source 10 and the primary central node, in series Further comprising a connected primary second voltage divider capacitor C2, a primary secondary secondary winding Np11 of the primary transformer, and a primary secondary secondary secondary winding Np21 of the secondary transformer, and the primary secondary winding of the primary transformer The first auxiliary winding Np11 and the primary secondary secondary winding Np12 of the first transformer are magnetically connected to the primary secondary winding Np1 of the first transformer, and the primary secondary secondary winding Np1 of the second transformer The winding Np21 and the primary secondary secondary winding Np21 of the second transformer may be magnetically connected to the primary secondary winding Np2 of the second transformer.

Due to this characteristic, it is possible to operate the secondary side output voltage in a low control range by the turn-number ratio (NS1/(NP1+NP11), NS2/(NP2+NP21)) of the transformer during forward operation, and reverse power In the case of transmission operation, the turn-to-number ratio (NP1/NS1, NP2/NS2) of the transformer can be transmitted to a low opposite, so that gain control can be designed easily during forward and reverse power transmission control.

As shown in FIG. 5, the other end of the primary winding Np1 of the first transformer and the other end of the primary winding Np2 of the second transformer are electrically connected, and the primary circuit unit 1100 has a primary first divided voltage. Further comprising a capacitor (C1) and a second voltage divider capacitor (C2) on the primary side, the first voltage divider capacitor (C1) and the 1 between the anode of the first voltage source 10 and the center node of the first primary side A primary-side first resonant reactance element (1111) is connected in series, and between the cathode of the first voltage source (10) and the primary-side central node, the primary-side second divided capacitor (C2) and the primary-side second resonance It may be characterized in that the reactance element 1112 is connected in series.

The other end of the primary-side first resonant reactance element 1111 and the other end of the primary-side second resonant reactance element 1112 are the other end of the primary winding Np1 of the first transformer and the primary winding of the second transformer ( It can be characterized by being electrically connected to the other end of Np2).

The other end of the secondary-side first resonant reactance element 1211 and the other end of the secondary-side second resonant reactance element 1212 are the other end of the secondary winding Ns1 of the first transformer and the secondary winding of the second transformer ( It can be characterized by being electrically connected to the other end of Ns2).

The secondary circuit part 1200 further includes a secondary first divided capacitor C3 and a secondary second divided capacitor C4 and C4, and one end and the other end of the secondary first divided capacitor C3 are respectively It is connected to the anode of the second voltage source 20 and the secondary center node, and one end and the other end of the secondary second voltage divider capacitor C4 are respectively connected to the secondary center node and the cathode of the second voltage source 20. It may be characterized by being connected.

The secondary-side first resonant reactance element 1211 further includes a third notch filter connected in series with the secondary-side first resonant capacitor CR1, and the secondary-side second resonant reactance element 1212 is the secondary side It may be characterized in that it further comprises a fourth notch filter connected in series with the second resonant capacitor (CR2).

The third notch filter and the fourth notch filter may include an inductor and a capacitor connected in parallel.

As shown in FIG. 4B, the secondary-side switch module includes a positive electrode of the second voltage source 20 and a 2-5th semiconductor switch S5 connected to the secondary-side central node, and a negative electrode of the second voltage source 20. And a 2-6th semiconductor switch S6 connected to the secondary-side central node.

As shown in FIG. 7B, the secondary circuit part 1200 includes a secondary first voltage divider capacitor C3 connected in series between the anode end of the second voltage source 20 and the secondary center node, and a first transformer. A secondary side first auxiliary winding (Ns11) and a secondary side first auxiliary winding (Ns21) of the second transformer, further comprising, between the negative end of the second voltage source 20 and the secondary center node, connected in series A secondary secondary voltage divider capacitor C4, a secondary secondary secondary winding Ns12 of the first transformer, and a secondary secondary secondary secondary winding Ns22 of the second transformer, and the secondary secondary secondary winding of the first transformer The first auxiliary winding Ns11 and the second auxiliary winding Ns12 on the secondary side of the first transformer are magnetically connected to the secondary winding Ns1 of the first transformer, and the secondary first auxiliary winding of the second transformer (Ns12) and the secondary secondary winding Ns22 of the second transformer may be magnetically connected to the secondary secondary winding Ns2 of the second transformer.

As shown in FIG. 5, the other end of the first transformer secondary winding Ns1 and the other end of the second transformer secondary winding Ns2 are electrically connected, and the secondary circuit part 1200 has a secondary first divided voltage. Further comprising a capacitor (C3) and a secondary-side second voltage divider capacitor (C4), the secondary-side first divided capacitor (C3) and the second between the anode of the second voltage source (20) and the second central node A secondary-side first resonant reactance element (1211) is connected in series, and between the cathode of the second voltage source and the secondary-side central node, a secondary-side second divided capacitor (C4) and the secondary-side second resonant reactance element ( 1212) may be connected in series.

10: first voltage source
20: second voltage source
1100: primary circuit part
1200: secondary circuit part
1110: primary resonant reactance element
1111: primary-side first resonant reactance element
1112: primary second resonant reactance element
1210: secondary side resonant reactance element
1211: secondary side first resonant reactance element
1212: secondary second resonant reactance element
C1: Primary first voltage divider capacitor
C2: primary second voltage divider capacitor
C3: Secondary first voltage divider capacitor
C4: Secondary voltage divider capacitor
Q1 to Q6: Primary switch module
S1 ~ S6: secondary switch module
Cr1: Primary first resonant capacitor
Cr2: primary secondary resonant capacitor
CR1: Secondary first resonant capacitor
CR2: Secondary resonant capacitor
T1: first transformer
T2: 2nd transformer
Np1: Primary winding of the first transformer
Np2: Primary winding of the second transformer
Np11: Primary auxiliary winding of the first transformer
Np21: Primary auxiliary winding of the second transformer
Ns1: Primary transformer secondary winding
Ns2: secondary winding of the second transformer
Ns11: Secondary auxiliary winding of the first transformer
Ns21: Secondary auxiliary winding of the second transformer

Claims (22)

As a bidirectional resonant DC-DC converter,
A primary-side switch module including a plurality of semiconductor switches, a primary winding of each of a plurality of transformers, a primary-side circuit unit including a plurality of primary-side resonance reactance elements, and connected to a first voltage source; And
A secondary-side switch module including a plurality of semiconductor switches, a plurality of secondary windings each magnetically connected to the plurality of transformers, a secondary-side circuit unit including a plurality of secondary-side resonance reactance elements, and connected to a second voltage source; And
A control unit for controlling the primary switch module and the secondary switch module; and
The control unit controls the semiconductor switches of the primary switch module and the secondary switch module to transfer electrical energy in both directions between the first voltage source and the second voltage source, among the primary switch module and the secondary switch module. By varying the switching frequency for at least one, the voltage gain, which is the magnitude of the output voltage relative to the magnitude of the input voltage, is controlled, and
The controller has a forward power transfer mode for transferring electric energy from the first voltage source to the second voltage source and a reverse power transfer mode for transferring electric energy from the second voltage source to the first voltage source,
In the forward power transfer mode, current flows through the primary resonant reactance element, no current flows through the secondary resonant reactance element, and in the reverse power transfer mode, current flows through the secondary resonant reactance element, No current flows through the secondary resonance reactance element
A bidirectional resonant DC-DC converter, characterized in that.

The method of claim 1,
The control unit,
The same in both the forward power transfer and the reverse power transfer mode, reducing the voltage gain by increasing the switching frequency and increasing the voltage gain by decreasing the switching frequency.
A bidirectional resonant DC-DC converter, characterized in that.

delete The method of claim 1,
The primary winding Np1 of the first transformer, which is one of the plurality of transformers, and the secondary winding Ns1 of the first transformer are magnetically connected,
The primary winding Np2 of the second transformer, which is another one of the plurality of transformers, and the secondary winding Ns2 of the second transformer are magnetically connected,
In the forward power transfer mode, the voltage of the first transformer secondary winding and the voltage of the second transformer secondary winding are added to be applied to a second voltage source, and in the reverse power transfer mode, the voltage of the first transformer primary winding and the second 2 The voltage of the primary winding of the transformer is added and applied to the first voltage source
A bidirectional resonant DC-DC converter, characterized in that.

The method of claim 4,
The first transformer primary winding and the first transformer secondary winding are wound in the same direction as each other,
The second transformer primary winding and the second transformer secondary winding are wound in opposite directions to each other
A bidirectional resonant DC-DC converter, characterized in that.

The method of claim 5,
The primary switch module,
Including 1-1 to 1-4 semiconductor switches,
The 1-1 and 1-2 semiconductor switches are connected in series,
Lessons 1-3 and 1-4 semiconductor switches are connected in series to have a full bridge structure,
Nodes to which the 1-1 and 1-2 semiconductor switches are connected are connected to one end of the primary winding of the first transformer,
The node to which the 1-3 and 1-4 semiconductor switches are connected is connected to one end of the primary winding of the second transformer,
The secondary side switch module,
Including the 2-1 to 2-4 semiconductor switch,
The 2-1 and 2-2 semiconductor switches are connected in series,
Lesson 2-3 2-4 Semiconductor switches are connected in series to have a full bridge structure,
Nodes to which the 2-1 and 2-2 semiconductor switches are connected are connected to one end of the secondary winding of the first transformer,
Lesson 2-3 The node to which the semiconductor switch is connected is connected to one end of the secondary winding of the second transformer.
A bidirectional resonant DC-DC converter, characterized in that.

The method of claim 5,
One end of the primary-side resonant reactance element, which is one of the plurality of primary-side resonant reactance elements, and one end of the primary-side secondary resonant reactance element, which is another one of the plurality of primary-side resonant reactance elements, are at a predetermined primary-side center Electrically connected to the node,
One end of the secondary-side first resonant reactance element, which is one of the plurality of secondary-side resonant reactance elements, and one end of the secondary-side secondary resonant reactance element, which is another one of the plurality of secondary-side resonant reactance elements, are centered on a predetermined secondary side. Electrically connected to the node,
The other end of the primary-side first resonant reactance element and the other end of the primary-side second resonant reactance element are electrically connected through a common connection line,
The other end of the secondary-side first resonant reactance element and the other end of the secondary-side second resonant reactance element are electrically connected through a common connection line.
A bidirectional resonant DC-DC converter, characterized in that.

The method of claim 7,
The primary-side first resonant reactance element includes a primary-side first resonant capacitor or a primary-side first resonant capacitor, and a primary-side first resonant inductor connected in series with the primary-side first resonant capacitor,
The primary-side second resonant reactance element includes a primary-side second resonant capacitor or a primary-side second resonant capacitor, and a primary-side second resonant inductor connected in series with the primary-side second resonant capacitor,
The secondary-side first resonant reactance element includes a secondary-side first resonant capacitor or a secondary-side first resonant capacitor, and a secondary-side first resonant inductor connected in series with the secondary-side first resonant capacitor,
The secondary-side second resonant reactance element includes a secondary-side second resonant capacitor or a secondary-side second resonant capacitor, and a secondary-side second resonant inductor connected in series with the secondary-side second resonant capacitor.
A bidirectional resonant DC-DC converter, characterized in that.

The method of claim 8,
The other end of the primary-side first resonant reactance element and the other end of the primary-side second resonant reactance element are electrically connected to the other end of the primary winding of the first transformer and the other end of the primary winding of the second transformer, respectively,
A bidirectional resonant DC-DC converter, characterized in that.

The method of claim 9,
The primary circuit part
Further comprising a primary-side first divided capacitor and a primary-side second divided capacitor,
One end and the other end of the primary-side first divided capacitor are respectively connected to the anode of the first voltage source and the primary-side central node,
One end and the other end of the primary second divided capacitor are connected to the primary central node and the cathode of the first voltage source, respectively
A bidirectional resonant DC-DC converter, characterized in that.

The method of claim 10,
The primary-side first resonant reactance element further includes a first notch filter connected in series with the primary-side first resonant capacitor,
The primary second resonant reactance element further comprises a second notch filter connected in series with the primary second resonant capacitor
A bidirectional resonant DC-DC converter, characterized in that.

The method of claim 11,
The first notch filter and the second notch filter include an inductor and a capacitor connected in parallel
A bidirectional resonant DC-DC converter, characterized in that.

The method of claim 9,
The primary switch module,
A 1-5th semiconductor switch connected to the anode of the first voltage source and the primary central node,
Further comprising a 1-6th semiconductor switch connected to the cathode of the first voltage source and the primary central node
A bidirectional resonant DC-DC converter, characterized in that.

The method of claim 9,
The primary circuit part
Between the positive end of the first voltage source and the primary-side central node, a primary-side first voltage divider capacitor connected in series, a primary primary secondary winding of the first transformer, and a primary secondary secondary winding of the second transformer, ,
Between the negative end of the first voltage source and the primary-side central node, further comprising a primary second voltage divider capacitor connected in series, a primary secondary secondary winding of the first transformer, and a primary secondary secondary secondary winding of the second transformer And
The primary first auxiliary winding of the first transformer and the primary second auxiliary winding of the first transformer are magnetically connected to the primary winding of the first transformer,
The primary first auxiliary winding of the second transformer and the primary second auxiliary winding of the second transformer are magnetically connected to the primary winding of the second transformer
A bidirectional resonant DC-DC converter, characterized in that.

The method of claim 8,
The other end of the primary winding of the first transformer and the other end of the primary winding of the second transformer are electrically connected,
The primary circuit part
Further comprising a primary-side first divided capacitor and a primary-side second divided capacitor,
The primary-side first voltage divider capacitor and the primary-side first resonant reactance element are connected in series between the anode of the first voltage source and the primary-side central node,
Between the cathode of the first voltage source and the center node on the primary side, a second voltage divider capacitor on a primary side and a second resonance reactance element on the primary side are connected in series
A bidirectional resonant DC-DC converter, characterized in that.

The method according to any one of claims 8 to 15,
The other end of the secondary-side first resonant reactance element and the other end of the secondary-side second resonant reactance element are electrically connected to the other end of the secondary winding of the first transformer and the other end of the secondary winding of the second transformer, respectively,
A bidirectional resonant DC-DC converter, characterized in that.

The method of claim 16,
The secondary circuit part
Further comprising a secondary-side first divided capacitor (C3) and a secondary-side second divided capacitor (C4),
One end and the other end of the secondary-side first divided capacitor are connected to the anode of the second voltage source and the secondary-side central node, respectively,
One end and the other end of the secondary second voltage divider capacitor are connected to the secondary center node and the cathode of the second voltage source, respectively
A bidirectional resonant DC-DC converter, characterized in that.

The method of claim 17,
The secondary-side first resonant reactance element further includes a third notch filter connected in series with the secondary-side first resonant capacitor,
The secondary-side second resonant reactance element further comprises a fourth notch filter connected in series with the secondary-side second resonant capacitor
A bidirectional resonant DC-DC converter, characterized in that.

The method of claim 18,
The third notch filter and the fourth notch filter include an inductor and a capacitor connected in parallel
A bidirectional resonant DC-DC converter, characterized in that.

The method of claim 16,
The secondary side switch module,
A 2-5th semiconductor switch connected to the anode of the second voltage source and the secondary center node,
Further comprising a 2-6th semiconductor switch connected to the cathode of the second voltage source and the secondary center node
A bidirectional resonant DC-DC converter, characterized in that.

The method of claim 16,
The secondary circuit part
Between the positive end of the second voltage source and the secondary center node, the secondary side first voltage divider capacitor connected in series, the secondary side first auxiliary winding of the first transformer, and the secondary side first auxiliary winding of the second transformer, ,
Between the negative end of the second voltage source and the secondary center node, a secondary secondary voltage divider capacitor connected in series, a secondary secondary secondary winding of the first transformer, and a secondary secondary secondary secondary winding of the second transformer And
The secondary secondary winding of the first transformer and the secondary secondary secondary winding of the first transformer are magnetically connected to the secondary winding of the first transformer,
The second secondary winding of the second transformer and the secondary secondary winding of the second transformer are magnetically connected to the secondary winding of the second transformer.
A bidirectional resonant DC-DC converter, characterized in that.

The method according to any one of claims 8 to 15,
The other end of the secondary winding of the first transformer and the other end of the secondary winding of the second transformer are electrically connected,
The secondary circuit part
Further comprising a secondary-side first divided capacitor and a secondary-side second divided capacitor,
The secondary-side first divided capacitor and the secondary-side first resonant reactance element are connected in series between the anode of the second voltage source and the secondary center node,
Between the cathode of the second voltage source and the center node on the secondary side, a secondary second voltage divider capacitor and the secondary second resonant reactance element are connected in series
A bidirectional resonant DC-DC converter, characterized in that.

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