Converter and bidirectional DC / DC conversion circuit thereof

Abstract

The present invention provides a converter and a bidirectional DC / DC conversion circuit thereof, wherein the conversion circuit includes a transformer, a first bridge arm circuit, a second bridge arm circuit, a first resonant circuit, and a second resonant circuit. The first bridge arm circuit and the first resonant circuit are connected to form a first power circuit, and the second bridge arm circuit and the second resonant circuit are connected to form a second power circuit. The first power circuit and the second power circuit are respectively arranged on either side of the transformer. The first bridge arm circuit and the second bridge arm circuit are respectively provided with a blocking switch tube, and the blocking switch tube is disconnected when the current in the first power circuit or the second power circuit reaches a preset threshold. The present invention can effectively block the oscillation circuit, thereby ensuring the monotonicity of the circuit output voltage and switching frequency, and can ensure that the output voltage gain is not lost, thereby ensuring the performance of the converter.

Description

Technical Field

[0001] The present invention relates to the technical field of conversion circuits, and in particular to a bidirectional DC / DC conversion circuit and a converter. Background Art

[0002] With the development of converter technology, converters with V2G and V2L functions are becoming increasingly widely used. Currently, converters with V2G (vehicle-to-grid) and V2L (vehicle-to-load) functions generally use bidirectional power conversion circuits based on Si MOSFETs. However, this circuit has application limitations. When the circuit power is high, the Si MOSFET's inherent parasitic inductance will cause oscillation when the secondary current is zero. This results in a non-monotonic relationship between the converter's output voltage and switching frequency, and reduces the output voltage gain, ultimately affecting the converter's performance. Summary of the Invention

[0003] The present invention aims to at least partially address one of the technical problems in the above-mentioned technologies. To this end, one object of the present invention is to provide a bidirectional DC / DC converter circuit that effectively blocks the oscillation loop, thereby ensuring the monotonicity of the circuit's output voltage and switching frequency, and ensuring that the output voltage gain is not lost, thereby maintaining converter performance.

[0004] A second object of the present invention is to provide a converter.

[0005] To achieve the above-mentioned objectives, an embodiment of the first aspect of the present invention proposes a bidirectional DC / DC conversion circuit, including a transformer, a first bridge arm circuit, a second bridge arm circuit, a first resonant circuit and a second resonant circuit, wherein the first bridge arm circuit and the first resonant circuit are connected to form a first power circuit, and the second bridge arm circuit and the second resonant circuit are connected to form a second power circuit, the first power circuit and the second power circuit are respectively arranged on both sides of the transformer, and the first bridge arm circuit and the second bridge arm circuit are respectively provided with a blocking switch tube, and the blocking switch tube is disconnected when the current of the first power circuit or the second power circuit reaches a preset threshold.

[0006] According to the bidirectional DC / DC conversion circuit proposed in an embodiment of the present invention, a first power circuit is formed by connecting a first bridge arm circuit and a first resonant circuit, and a second power circuit is formed by connecting a second bridge arm circuit and a second resonant circuit. The first power circuit and the second power circuit are respectively arranged on both sides of the transformer, and blocking switch tubes are respectively provided in the first bridge arm circuit and the second bridge arm circuit, wherein the blocking switch tube is disconnected when the current in the first power circuit or the second power circuit reaches a preset threshold value. Thus, the oscillation circuit can be effectively blocked, thereby ensuring the monotonicity of the circuit output voltage and switching frequency, and ensuring that the output voltage gain is not lost, thereby ensuring the performance of the converter.

[0007] In addition, the bidirectional DC / DC converter circuit proposed in the above embodiment of the present invention may also have the following additional technical features:

[0008] According to one embodiment of the present invention, the first bridge arm circuit includes: a first switching tube, wherein the drain of the first switching tube is connected to the positive electrode of the first power supply; a second switching tube, wherein the drain of the second switching tube is connected to the positive electrode of the first power supply; a third switching tube, wherein the drain of the third switching tube is connected to the source of the first switching tube; a fourth switching tube, wherein the drain of the fourth switching tube is connected to the source of the second switching tube; a first blocking switching tube, wherein the source of the first blocking switching tube is connected to the negative electrode of the first power supply, and the drain of the first blocking switching tube is respectively connected to the source of the third switching tube and the source of the fourth switching tube, and the first blocking switching tube is disconnected when the current of the first power loop reaches a preset threshold.

[0009] According to an embodiment of the present invention, the first switch tube, the second switch tube, the third switch tube and the fourth switch tube are Si Mosfet switch tubes, and the first blocking switch tube is a SiC Mosfet switch tube.

[0010] According to one embodiment of the present invention, the second bridge arm circuit includes: a fifth switch tube, the drain of the fifth switch tube is connected to the positive electrode of the second power supply; a sixth switch tube, the drain of the sixth switch tube is connected to the positive electrode of the second power supply; a seventh switch tube, the drain of the seventh switch tube is connected to the source of the fifth switch tube; an eighth switch tube, the drain of the eighth switch tube is connected to the source of the sixth switch tube; a second blocking switch tube, the source of the second blocking switch tube is connected to the negative electrode of the second power supply, the drain of the second blocking switch tube is respectively connected to the source of the seventh switch tube and the source of the eighth switch tube, and the second blocking switch tube is disconnected when the current of the second power loop reaches a preset threshold.

[0011] According to an embodiment of the present invention, the fifth switch tube, the sixth switch tube, the seventh switch tube and the eighth switch tube are all Si Mosfet switch tubes, and the second blocking switch tube is a SiC Mosfet switch tube.

[0012] According to one embodiment of the present invention, the first resonant circuit includes: a first resonant inductor, one end of the first resonant inductor is respectively connected to the source of the first switching tube and the drain of the third switching tube, and the other end of the first resonant inductor is connected to one end of the primary side of the transformer; a first resonant capacitor, one end of the first resonant capacitor is respectively connected to the source of the second switching tube and the drain of the fourth switching tube, and the other end of the first resonant capacitor is connected to the other end of the primary side of the transformer.

[0013] According to one embodiment of the present invention, the first resonant capacitor is a polarized capacitor, and the positive electrode of the first resonant capacitor is connected to the source of the second switching tube and the drain of the fourth switching tube respectively, and the negative electrode of the first resonant capacitor is connected to the other end of the primary side of the transformer.

[0014] According to one embodiment of the present invention, the second resonant circuit includes: a second resonant inductor, one end of the second resonant inductor is respectively connected to the source of the fifth switching tube and the drain of the seventh switching tube, and the other end of the second resonant inductor is connected to one end of the secondary side of the transformer; a second resonant capacitor, one end of the second resonant capacitor is respectively connected to the source of the sixth switching tube and the drain of the eighth switching tube, and the other end of the second resonant capacitor is connected to the other end of the secondary side of the transformer.

[0015] According to one embodiment of the present invention, the second resonant capacitor is a polarized capacitor, and the positive electrode of the second resonant capacitor is connected to the source of the sixth switching tube and the drain of the eighth switching tube respectively, and the negative electrode of the second resonant capacitor is connected to the other end of the secondary side of the transformer.

[0016] To achieve the above-mentioned object, a second embodiment of the present invention provides a converter, comprising the bidirectional DC / DC conversion circuit provided in the first embodiment.

[0017] The converter proposed according to an embodiment of the present invention, including the bidirectional DC / DC conversion circuit proposed in the above embodiment, can effectively block the oscillation loop, thereby ensuring the monotonicity of the circuit output voltage and switching frequency, and can ensure that the output voltage gain is not lost, thereby ensuring the performance of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 1 is a block diagram of a bidirectional DC / DC converter circuit according to an embodiment of the present invention;

[0019] Figure 2 A topological diagram of a bidirectional DC / DC converter circuit according to an embodiment of the present invention;

[0020] Figure 3 A schematic diagram of the working process of a bidirectional DC / DC converter circuit according to an embodiment of the present invention;

[0021] Figure 4 This is a control timing diagram of a bidirectional DC / DC converter circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] Figure 1 4 is a block diagram of a bidirectional DC / DC converter circuit according to an embodiment of the present invention.

[0024] like Figure 1 As shown, the bidirectional DC / DC conversion circuit of an embodiment of the present invention includes a transformer 10, a first bridge arm circuit 20, a second bridge arm circuit 30, a first resonant circuit 40 and a second resonant circuit 50, wherein the first bridge arm circuit 20 and the first resonant circuit 40 are connected to form a first power circuit, and the second bridge arm circuit 30 and the second resonant circuit 50 are connected to form a second power circuit. The first power circuit and the second power circuit are respectively arranged on both sides of the transformer 10, and the first bridge arm circuit 20 and the second bridge arm circuit 30 are respectively provided with a blocking switch tube, which is disconnected when the current in the first power circuit or the second power circuit reaches a preset threshold.

[0025] Specifically, if Figure 2As shown, the first bridge arm circuit 20 may be provided with five switching transistors, and the five switching transistors may be connected in a full-bridge manner to form the first bridge arm circuit 20. The second bridge arm circuit 30 may also be provided with five switching transistors, and the five switching transistors may also be connected in a full-bridge manner to form the second bridge arm circuit 30. In addition, the first bridge arm circuit 20 and the first resonant circuit 40 may form a first power loop and be connected in series with the primary side of the transformer 10. The second bridge arm circuit 30 and the second resonant circuit 50 may form a second power loop and be connected in series with the secondary side of the transformer 10. When the current in the second power loop reaches a preset threshold, for example, 0.05V, and is about to reach zero, the blocking switch in the second bridge arm circuit 30 may be disconnected in advance, thereby effectively blocking the oscillation loop, ensuring the monotonicity of the circuit output voltage and switching frequency, and ensuring that the output voltage gain is not lost, thereby ensuring the performance of the converter. It should be noted that the first power loop and the second power loop may be symmetrically arranged on both sides of the transformer 10, that is, symmetrically arranged on the primary and secondary sides of the transformer 10.

[0026] In one embodiment of the present invention, Figure 2 As shown, the first bridge arm circuit 20 includes: a first switch tube Q1, wherein the drain of the first switch tube Q1 is connected to the positive electrode of the first power supply U1; a second switch tube Q2, wherein the drain of the second switch tube Q2 is connected to the positive electrode of the first power supply U1; a third switch tube Q3, wherein the drain of the third switch tube Q3 is connected to the source of the first switch tube Q1; a fourth switch tube Q4, wherein the drain of the fourth switch tube Q4 is connected to the source of the second switch tube Q2; a first blocking switch tube Q9, wherein the source of the first blocking switch tube Q9 is connected to the negative electrode of the first power supply U1, and the drain of the first blocking switch tube Q9 is respectively connected to the source of the third switch tube Q3 and the source of the fourth switch tube Q4. The first blocking switch tube Q9 is disconnected when the current in the first power loop reaches a preset threshold.

[0027] In one embodiment of the present invention, Figure 2 As shown, the second bridge arm circuit 30 includes: a fifth switch tube Q5, wherein the drain of the fifth switch tube Q5 is connected to the positive electrode of the second power supply U2; a sixth switch tube Q6, wherein the drain of the sixth switch tube Q6 is connected to the positive electrode of the second power supply U2; a seventh switch tube Q7, wherein the drain of the seventh switch tube Q7 is connected to the source of the fifth switch tube Q5; an eighth switch tube Q8, wherein the drain of the eighth switch tube Q8 is connected to the source of the sixth switch tube Q6; and a second blocking switch tube Q10, wherein the source of the second blocking switch tube Q10 is connected to the negative electrode of the second power supply U2, and the drain of the second blocking switch tube Q10 is respectively connected to the source of the seventh switch tube Q7 and the source of the eighth switch tube Q8. The second blocking switch tube Q10 is disconnected when the current in the second power loop reaches a preset threshold.

[0028] The first, second, third, and fourth switches Q1, Q2, Q3, and Q4 are Si MOSFETs, while the first blocking switch Q9 is a SiC MOSFET. The fifth, sixth, seventh, and eighth switches Q5, Q6, Q7, and Q8 are Si MOSFETs, while the second blocking switch Q10 is a SiC MOSFET. By using two SiC MOSFETs, the oscillation circuit can be effectively blocked, ensuring converter performance and reducing costs.

[0029] In one embodiment of the present invention, Figure 2 As shown, the first resonant circuit 40 includes: a first resonant inductor L1, one end of which is respectively connected to the source of the first switch tube Q1 and the drain of the third switch tube Q3, and the other end of the first resonant inductor L1 is connected to one end of the primary side of the transformer 10; a first resonant capacitor C1, one end of which is respectively connected to the source of the second switch tube Q2 and the drain of the fourth switch tube Q4, and the other end of the first resonant capacitor C1 is connected to the other end of the primary side of the transformer 10.

[0030] The first resonant capacitor C1 is a polarized capacitor, and the positive electrode of the first resonant capacitor C1 is connected to the source of the second switch tube Q2 and the drain of the fourth switch tube Q4 respectively, and the negative electrode of the first resonant capacitor C1 is connected to the other end of the primary side of the transformer 10.

[0031] In one embodiment of the present invention, Figure 2 As shown, the second resonant circuit 50 includes: a second resonant inductor L2, one end of which is respectively connected to the source of the fifth switch tube Q5 and the drain of the seventh switch tube Q7, and the other end of the second resonant inductor L2 is connected to one end of the secondary side of the transformer 10; a second resonant capacitor C2, one end of which is respectively connected to the source of the sixth switch tube Q6 and the drain of the eighth switch tube Q8, and the other end of the second resonant capacitor C2 is connected to the other end of the secondary side of the transformer 10.

[0032] The second resonant capacitor C2 is a polarized capacitor, and the positive electrode of the second resonant capacitor C2 is connected to the source of the sixth switch tube Q6 and the drain of the eighth switch tube Q8 respectively, and the negative electrode of the second resonant capacitor C2 is connected to the other end of the secondary side of the transformer 10.

[0033] Based on the above embodiments, a bidirectional DC / DC conversion circuit of the present invention can be constructed. Figure 3 and Figure 4 The control logic of the bidirectional DC / DC conversion circuit of the present invention is further explained.

[0034] like Figure 3 and Figure 4 As shown, when the bidirectional DC / DC converter circuit of the present invention works in the forward direction, that is, along Figure 3 When the arrow direction shown moves in the first power loop, the first blocking switch tube Q9 always remains closed, and the output current of the first power supply U1 is converted into positive and negative square waves through the first switch tube Q1 and the fourth switch tube Q4, and then can be converted to the secondary side of the transformer 10 through the first resonant circuit 40 and the transformer 10 to form a secondary current, and along Figure 3 The arrow shown in the figure moves in the second power loop. When the secondary current passes through the fifth switch tube Q5 and the eighth switch tube Q8, the second blocking switch tube Q10 can be turned on, thereby avoiding the secondary current from passing through the body diode of the second blocking switch tube Q10 and generating large conduction loss.

[0035] Furthermore, when the secondary current through the fifth switch Q5 and the eighth switch Q8 reaches a preset threshold, such as 0.05V, and is about to reach zero, the second blocking switch Q10 can be disconnected in advance, thereby preventing reverse discharge of the second power source U2 through the parasitic capacitance of the fifth switch Q5, the sixth switch Q6, the seventh switch Q7, and the eighth switch Q8. It should be noted that typical switching tubes have parasitic capacitance, and this parasitic capacitance can cause oscillation when the current through the switching tubes is zero, thereby reducing the gain of the circuit output voltage and degrading the performance of the converter. Therefore, the present invention effectively blocks the oscillation loop by providing the first blocking switch Q9 and the second blocking switch Q10, thereby ensuring the gain of the circuit output voltage and the performance of the converter. Among them, the first switching tube Q1 and the fourth switching tube Q4 can be alternately turned on with the second opening tube Q2 and the third opening tube Q3. The above embodiment describes the forward working process of the bidirectional DC / DC conversion circuit of the present invention. The reverse working process of the bidirectional DC / DC conversion circuit of the present invention is similar to the forward working process of the bidirectional DC / DC conversion circuit of the present invention, and will not be described here to avoid repetition.

[0036] According to the bidirectional DC / DC conversion circuit proposed in an embodiment of the present invention, a first power circuit is formed by connecting a first bridge arm circuit and a first resonant circuit, and a second power circuit is formed by connecting a second bridge arm circuit and a second resonant circuit. The first power circuit and the second power circuit are respectively arranged on both sides of the transformer, and blocking switch tubes are respectively provided in the first bridge arm circuit and the second bridge arm circuit, wherein the blocking switch tube is disconnected when the current in the first power circuit or the second power circuit reaches a preset threshold value. Thus, the oscillation circuit can be effectively blocked, thereby ensuring the monotonicity of the circuit output voltage and switching frequency, and ensuring that the output voltage gain is not lost, thereby ensuring the performance of the converter.

[0037] Corresponding to the bidirectional DC / DC conversion circuit proposed in the above embodiment, the present invention further proposes a converter.

[0038] The converter provided in the embodiment of the present invention includes the bidirectional DC / DC converter circuit provided in the above embodiment, and its specific implementation manner refers to the above embodiment.

[0039] The converter proposed according to an embodiment of the present invention, including the bidirectional DC / DC conversion circuit proposed in the above embodiment, can effectively block the oscillation loop, thereby ensuring the monotonicity of the circuit output voltage and switching frequency, and can ensure that the output voltage gain is not lost, thereby ensuring the performance of the product.

[0040] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. "Multiple" means two or more, unless otherwise specifically defined.

[0041] In the present invention, unless otherwise expressly specified or limited, terms such as "connected" and "connection" should be understood in a broad sense. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0042] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0043] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

Claims

1. A bidirectional DC / DC conversion circuit, characterized in that: The invention comprises a transformer, a first bridge arm circuit, a second bridge arm circuit, a first resonant circuit, and a second resonant circuit, wherein the first bridge arm circuit and the first resonant circuit are connected to form a first power circuit, and the second bridge arm circuit and the second resonant circuit are connected to form a second power circuit. The first power circuit and the second power circuit are respectively arranged on both sides of the transformer. The first bridge arm circuit and the second bridge arm circuit are respectively provided with a blocking switch tube. The blocking switch tube is disconnected when the current of the first power circuit or the second power circuit reaches a preset threshold to prevent reverse discharge of the parasitic capacitance of the switch tube in the first bridge arm circuit or the second bridge arm circuit. The first bridge arm circuit includes: a first switch tube, wherein the drain of the first switch tube is connected to the positive electrode of the first power supply; a second switch tube, wherein the drain of the second switch tube is connected to the positive electrode of the first power supply; a third switch tube, wherein the drain of the third switch tube is connected to the source of the first switch tube; a fourth switch tube, wherein the drain of the fourth switch tube is connected to the source of the second switch tube; a first blocking switch tube, wherein the source of the first blocking switch tube is connected to the negative electrode of the first power supply, and the drain of the first blocking switch tube is respectively connected to the source of the third switch tube and the source of the fourth switch tube, and the first blocking switch tube is disconnected when the current of the first power loop reaches a preset threshold. The second bridge arm circuit includes: a fifth switch tube, the drain of the fifth switch tube is connected to the positive electrode of the second power supply; a sixth switch tube, the drain of the sixth switch tube is connected to the positive electrode of the second power supply; a seventh switch tube, the drain of the seventh switch tube is connected to the source of the fifth switch tube; an eighth switch tube, the drain of the eighth switch tube is connected to the source of the sixth switch tube; a second blocking switch tube, the source of the second blocking switch tube is connected to the negative electrode of the second power supply, the drain of the second blocking switch tube is respectively connected to the source of the seventh switch tube and the source of the eighth switch tube, and the second blocking switch tube is disconnected when the current of the second power loop reaches a preset threshold.

2. The bidirectional DC / DC converter circuit according to claim 1, characterized in that: in, The first switch tube, the second switch tube, the third switch tube and the fourth switch tube are Si Mosfet switch tubes, and the first blocking switch tube is a SiC Mosfet switch tube.

3. The bidirectional DC / DC converter circuit according to claim 2, characterized in that: in, The fifth switch tube, the sixth switch tube, the seventh switch tube and the eighth switch tube are all Si Mosfet switch tubes, and the second blocking switch tube is a SiC Mosfet switch tube.

4. The bidirectional DC / DC converter circuit according to claim 3, characterized in that: The first resonant circuit comprises: a first resonant inductor, one end of which is connected to the source of the first switching transistor and the drain of the third switching transistor, respectively, and the other end of which is connected to one end of the primary side of the transformer; A first resonant capacitor, one end of the first resonant capacitor is connected to the source of the second switching tube and the drain of the fourth switching tube respectively, and the other end of the first resonant capacitor is connected to the other end of the primary side of the transformer.

5. The bidirectional DC / DC converter circuit according to claim 4, characterized in that: in, The first resonant capacitor is a polarized capacitor, and the positive electrode of the first resonant capacitor is connected to the source of the second switching tube and the drain of the fourth switching tube respectively, and the negative electrode of the first resonant capacitor is connected to the other end of the primary side of the transformer.

6. The bidirectional DC / DC converter circuit according to claim 5, characterized in that: The second resonant circuit comprises: a second resonant inductor, one end of the second resonant inductor being connected to the source of the fifth switching transistor and the drain of the seventh switching transistor, respectively, and the other end of the second resonant inductor being connected to one end of the secondary side of the transformer; A second resonant capacitor, one end of the second resonant capacitor is connected to the source of the sixth switching tube and the drain of the eighth switching tube respectively, and the other end of the second resonant capacitor is connected to the other end of the secondary side of the transformer.

7. The bidirectional DC / DC converter circuit according to claim 6, characterized in that: in, The second resonant capacitor is a polarized capacitor, and the positive electrode of the second resonant capacitor is connected to the source of the sixth switching tube and the drain of the eighth switching tube respectively, and the negative electrode of the second resonant capacitor is connected to the other end of the secondary side of the transformer.

8. A converter, characterized in that: The invention comprises a bidirectional DC / DC conversion circuit according to any one of claims 1 to 7.

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