DCDC circuit topological structure

Abstract

The invention belongs to the technical field of circuits, and discloses a DCDC circuit topological structure which comprises a port VBUS + and a port VBUS-, the port VBUS + is connected with one end of an inductor L1, the other end of the inductor L1 is connected with one end of a switching tube Q1 and one end of a capacitor C3, the other end of the capacitor C3 is connected with a first port in the front side of a transformer assembly, the port VBUS-is connected with one end of an inductor L2, and the other end of the inductor L2 is connected with a second port in the front side of the transformer assembly. The other end of the inductor L2 is connected with one end of a switching tube Q2 and one end of a capacitor C4, the other end of the switching tube Q2 is connected with the other end of the switching tube Q1 and a second port in the front side of the transformer assembly, the other end of the capacitor C4 is connected with a third port in the front side of the transformer assembly, and a first port in the rear side of the transformer assembly is connected with a port VBAT +. A second port on the rear side of the transformer assembly is connected with one end of a switch tube Q3, and the other end of the switch tube Q3 is connected with a port VBAT-. The invention has the beneficial effects of simple structure and low cost, and can meet the bidirectional working requirement of charging and discharging the battery.

Description

Technical Field

[0001] The present invention relates to the field of circuit technology, and in particular to a DCDC circuit topology structure. Background Art

[0002] In photovoltaic, energy storage and other applications, the charging and discharging of batteries are involved, which requires a bidirectional DCDC circuit topology. When there is external power, DCDC charges the battery in the forward direction; when there is no external power supply, the battery needs to discharge to the outside world through DCDC in the reverse direction. There are many bidirectional DCDC topologies, and the Buck / Boost+LLC topology is currently popular in the industry. Buck / Boost is responsible for voltage regulation, and LLC is responsible for isolation. The topology is stable and reliable, but the two-stage structure has many devices and the cost remains high. Especially in photovoltaic + inverter applications, the photovoltaic bus comes out with an 800V bus, and the subsequent inverter requires ±400V. For example Figure 1 The current common practice is to obtain ±400V by connecting capacitors in series, but when the load is unbalanced, additional circuits are required to balance the voltage of the series capacitors, which increases the cost and sacrifices efficiency. When there is battery charging, a charging circuit for the positive and negative busbars can be designed to achieve a certain balance, but when the battery is fully charged, the charging circuit will lose its balancing function.

[0003] Therefore, it is necessary to provide a DCDC circuit topology with simple structure and low cost, which can meet the bidirectional working requirements of charging and discharging the battery. Summary of the invention

[0004] The invention discloses a DCDC circuit topology structure, relates to the field of power electronics technology, can be widely used in energy storage and charging, and can effectively solve the technical problems involved in the background technology.

[0005] To achieve the above object, the technical solution of the present invention is:

[0006] A DCDC circuit topology structure includes a port VBUS+ and a port VBUS-, wherein the port VBUS+ is connected to one end of an inductor L1, the other end of the inductor L1 is connected to one end of a switch tube Q1 and one end of a capacitor C3, the other end of the capacitor C3 is connected to port one on the front side of a transformer assembly, the port VBUS- is connected to one end of an inductor L2, the other end of the inductor L2 is connected to one end of a switch tube Q2 and one end of a capacitor C4, the other end of the switch tube Q2 is connected to the other end of the switch tube Q1 and port two on the front side of the transformer assembly, the other end of the capacitor C4 is connected to port three on the front side of the transformer assembly, port one on the rear side of the transformer assembly is connected to port VBAT+, port two on the rear side of the transformer assembly is connected to one end of the switch tube Q3, and the other end of the switch tube Q3 is connected to port VBAT-.

[0007] As a preferred improvement of the present invention: the inductor L1 and the inductor L2 are two coils of common mode inductor.

[0008] As a preferred improvement of the present invention: the port VBUS+ is connected to one end of the capacitor C1, the other end of the capacitor C1 is connected to one end of the capacitor C2, the other end of the switch tube Q1 and the port GND, and the other end of the capacitor C2 is connected to the port VBUS-.

[0009] As a preferred improvement of the present invention: the types of the switch tube Q1 include but are not limited to MOS tubes, IGBTs, bipolar triodes, silicon carbide and gallium nitride; the types of the switch tube Q2 include but are not limited to MOS tubes, IGBTs, bipolar triodes, silicon carbide and gallium nitride; the types of the switch tube Q3 include but are not limited to MOS tubes, IGBTs, bipolar triodes, silicon carbide and gallium nitride.

[0010] As a preferred improvement of the present invention: the types of the switch tube Q1 and the switch tube Q2 include but are not limited to MOS tubes, IGBTs, bipolar triodes, silicon carbide and gallium nitride, and the switch tube Q3 is a diode, or the switch tube Q1 and the switch tube Q2 are diodes, and the types of the switch tube Q3 include but are not limited to MOS tubes, IGBTs, bipolar triodes, silicon carbide and gallium nitride.

[0011] As a preferred improvement of the present invention: the port VBAT+ is connected to one end of the capacitor C5, and the other end of the capacitor C5 is connected to the port VBAT- and the port AGND.

[0012] As a preferred improvement of the present invention: the transformer assembly includes a plurality of transformers.

[0013] As a preferred improvement of the present invention: the transformer assembly includes a transformer T1, the other end of the capacitor C3 is connected to pin 1 of the transformer T1, pin 2 of the transformer T1 is connected to pin 3 of the transformer T1 and the other end of the switch tube Q1, pin 4 of the transformer T1 is connected to the other end of the capacitor C4, pin 5 of the transformer T1 is connected to one end of the switch tube Q3, pin 6 of the transformer T1 is connected to port VBAT+, pin 1 and pin 2 of the transformer T1 share a coil, pin 3 and pin 4 of the transformer T1 share a coil, and pin 5 and pin 6 of the transformer T1 share a coil.

[0014] As a preferred improvement of the present invention: the other end of the capacitor C3 is connected to one end of the inductor L3, the other end of the inductor L3 is connected to one end of the inductor L4 and port 2 on the front side of the transformer assembly, and the other end of the inductor L4 is connected to the other end of the capacitor C4.

[0015] As a preferred improvement of the present invention: the switch tube Q1, the switch tube Q2 and the switch tube Q3 are all MOS tubes, the drain of the switch tube Q1 is connected to the other end of the inductor L1, the source of the switch tube Q1 is connected to the drain of the switch tube Q2, the source of the switch tube Q2 is connected to the other end of the inductor L2, the drain of the switch tube Q3 is connected to port 2 on the rear side of the transformer assembly, and the source of the switch tube Q3 is connected to the port VBAT-.

[0016] The beneficial effects of the present invention are as follows:

[0017] A new bidirectional DCDC topology is proposed, which has a simple structure and low cost. It can meet the bidirectional working requirements of charging and discharging the battery, and can automatically balance the bus voltage regardless of whether the battery is charging or not, eliminating the need for an additional balancing circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0019] Figure 1 For the existing circuit structure;

[0020] Figure 2 A schematic diagram of a DCDC circuit topology structure of the present invention;

[0021] Figure 3 The multi-transformer of the present invention is shown in FIG. Figure 1 ;

[0022] Figure 4 The multi-transformer of the present invention is shown in FIG. Figure 2 ;

[0023] Figure 5 The multi-transformer of the present invention is shown in FIG. Figure 3 ;

[0024] Figure 6 This is a schematic diagram of the one-way conversion of the present invention. Figure 1 ;

[0025] Figure 7 This is a schematic diagram of the one-way conversion of the present invention. Figure 2 ;

[0026] Figure 8 The structure of the inductor and transformer of the present invention is shown in FIG. Figure 1 ;

[0027] Fig. 9 The structure of the inductor and transformer of the present invention is shown in FIG. Figure 2 . DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention will be described clearly and completely below in combination with the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0029] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0030] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0031] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0033] See also Figure 2As shown, the present invention provides a DCDC circuit topology structure, including a port VBUS+ and a port VBUS-, an input bus, a photovoltaic interface, etc., the port VBUS+ is connected to one end of the inductor L1 (common mode inductor pin 1), the other end of the inductor L1 (common mode inductor pin 2) is connected to one end of the switch tube Q1 and one end of the capacitor C3, the other end of the capacitor C3 is connected to the port 1 on the front side of the transformer component (pin 1 of the transformer T1), the port VBUS- is connected to one end of the inductor L2 (common mode inductor pin 3), the other end of the inductor L2 ... The inductive pin 4) connects one end of the switch tube Q2 and one end of the capacitor C4, the other end of the switch tube Q2 connects the other end of the switch tube Q1 and the port 2 on the front side of the transformer assembly (pin 2 of the transformer T1), the other end of the capacitor C4 connects the port 3 on the front side of the transformer assembly (pin 4 of the transformer T1), the port 1 on the rear side of the transformer assembly (pin 6 of the transformer T1) connects the port VBAT+, the port 2 on the rear side of the transformer assembly (pin 5 of the transformer T1) connects one end of the switch tube Q3, and the other end of the switch tube Q3 connects the port VBAT-. The port VBUS+ connects one end of the capacitor C1, the other end of the capacitor C1 connects one end of the capacitor C2, the other end of the switch tube Q1 and the port GND, and the other end of the capacitor C2 connects the port VBUS-. The port VBAT+ connects one end of the capacitor C5, the other end of the capacitor C5 connects the port VBAT- and the port AGND, and the port GND and the port AGND can be connected to the same ground or to different ground ports. The transformer assembly includes a transformer T1, the other end of the capacitor C3 is connected to pin 1 of the transformer T1, pin 2 of the transformer T1 is connected to pin 3 of the transformer T1 and the other end of the switch tube Q1, pin 4 of the transformer T1 is connected to the other end of the capacitor C4, pin 5 of the transformer T1 is connected to one end of the switch tube Q3, pin 6 of the transformer T1 is connected to port VBAT+, pin 1 and pin 2 of the transformer T1 share a coil, pin 3 and pin 4 of the transformer T1 share a coil, and pin 5 and pin 6 of the transformer T1 share a coil. The switch tube Q1, the switch tube Q2 and the switch tube Q3 are all MOS tubes, the drain of the switch tube Q1 is connected to the other end of the inductor L1, the source of the switch tube Q1 is connected to the drain of the switch tube Q2, the source of the switch tube Q2 is connected to the other end of the inductor L2, the drain of the switch tube Q3 is connected to port 2 on the rear side of the transformer component (pin 2 of the transformer T1), and the source of the switch tube Q3 is connected to the port VBAT-.

[0034] For the convenience of description, it is agreed that the circuit works forward when charging the battery and works reversely when discharging the battery. The high-voltage bus side is the primary side, and the battery side is the secondary side. The circuit structure is shown in the figure, which consists of a coupled inductor, an isolation capacitor, a transformer, and a power switch tube.

[0035] When working in the forward direction (battery charging):

[0036] Q1 / Q2 are synchronous switches, and Q3 is a complementary switch to Q1 / Q2.

[0037] When Q1 / Q2 is turned on, Q3 is turned off, inductor L1 stores energy through Q1 / Q2, and transformer T1 and capacitor C2 / C4 are reset.

[0038] When Q1 / Q2 is turned off, Q3 is turned on, and the energy of inductor L1 is transferred to the battery side through capacitor C3 / C4 and the transformer.

[0039] When working in reverse (battery discharge):

[0040] When Q3 is turned on, Q1 / Q2 is turned off, and the battery energy is transferred to the bus side through C3 / C4 and L1, and L1 stores energy.

[0041] When Q3 is turned off, Q1 / Q2 is turned on, inductor L1 continues to flow, energy is released to the bus side, and C3 / C4 and T1 are reset.

[0042] When neither charging nor discharging:

[0043] The working mode is similar to the previous one, Q1 / Q2 and Q3 are still working. When the voltages on C1 / C2 are equal, the circuit is equivalent to working at no-load output. When the voltages on C1 / C2 are unequal, the higher side will release energy, and the energy will flow from the higher side through the capacitor and transformer to the lower side, thus completing the automatic voltage balance on C1 and C2.

[0044] The topology is simple, the number of components is small, and the cost is low. The bidirectional DCDC conversion of battery charging and discharging can be completed. In the positive and negative power supply of capacitors in series, the capacitor voltage can be automatically balanced without the need for additional circuits. The inductor L1 and the inductor L2 are two coils of a common mode inductor, or they can be two independent inductors, that is, the inductor L1 and the inductor L2 are not coupled.

[0045] When the circuit works bidirectionally, the types of the switch tube Q1 include but are not limited to MOS tube, IGBT, bipolar triode, silicon carbide and gallium nitride, the types of the switch tube Q2 include but are not limited to MOS tube, IGBT, bipolar triode, silicon carbide and gallium nitride, and the types of the switch tube Q3 include but are not limited to MOS tube, IGBT, bipolar triode, silicon carbide and gallium nitride.

[0046] See also Figure 6-Figure 7As shown, when the circuit works unidirectionally, the types of the switch tube Q1 and the switch tube Q2 include but are not limited to MOS tubes, IGBTs, bipolar triodes, silicon carbide and gallium nitride, and the switch tube Q3 is a diode, or the switch tube Q1 and the switch tube Q2 are diodes, and the types of the switch tube Q3 include but are not limited to MOS tubes, IGBTs, bipolar triodes, silicon carbide and gallium nitride.

[0047] See also Figure 3-Figure 5 As shown, the transformer assembly includes multiple transformers, two of which are shown in the figure, and three different series-parallel connection methods are adopted. Of course, more transformers can also be used. It needs to be further explained that the use of other components to achieve the above-mentioned effects should all fall within the inventive concept of the present invention and should fall within the protection scope of the present invention.

[0048] See also Figure 8-Figure 9 As shown, different from Figure 1 The transformer in the middle is used as a transformer, and the primary excitation inductor is used as a common inductor to reset the intermediate capacitor. In this embodiment, the transformer is split into an inductor and used as a transformer. The other end of the capacitor C3 is connected to one end of the inductor L3, and the other end of the inductor L3 is connected to one end of the inductor L4 and the port 2 on the front side of the transformer assembly, and the other end of the inductor L4 is connected to the other end of the capacitor C4. Alternatively, the other end of the capacitor C3 is connected to one end of the inductor L3, and the other end of the inductor L3 is connected to the other end of the capacitor C4.

[0049] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the embodiments. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A DCDC circuit topology structure, characterized in that: It includes a port VBUS+ and a port VBUS-, wherein the port VBUS+ is connected to one end of the inductor L1, the other end of the inductor L1 is connected to one end of the switch tube Q1 and one end of the capacitor C3, the other end of the capacitor C3 is connected to port one on the front side of the transformer assembly, the port VBUS- is connected to one end of the inductor L2, the other end of the inductor L2 is connected to one end of the switch tube Q2 and one end of the capacitor C4, the other end of the switch tube Q2 is connected to the other end of the switch tube Q1 and port two on the front side of the transformer assembly, the other end of the capacitor C4 is connected to port three on the front side of the transformer assembly, port one on the rear side of the transformer assembly is connected to port VBAT+, port two on the rear side of the transformer assembly is connected to one end of the switch tube Q3, and the other end of the switch tube Q3 is connected to port VBAT-.

2. A DCDC circuit topology structure according to claim 1, characterized in that: The inductor L1 and the inductor L2 are two coils of a common mode inductor.

3. A DCDC circuit topology structure according to claim 1, characterized in that: The port VBUS+ is connected to one end of the capacitor C1, the other end of the capacitor C1 is connected to one end of the capacitor C2, the other end of the switch tube Q1 and the port GND, and the other end of the capacitor C2 is connected to the port VBUS-.

4. A DCDC circuit topology structure according to claim 1, characterized in that: The types of the switch tube Q1 include but are not limited to MOS tube, IGBT, bipolar triode, silicon carbide and gallium nitride, the types of the switch tube Q2 include but are not limited to MOS tube, IGBT, bipolar triode, silicon carbide and gallium nitride, and the types of the switch tube Q3 include but are not limited to MOS tube, IGBT, bipolar triode, silicon carbide and gallium nitride.

5. A DCDC circuit topology structure according to claim 1, characterized in that: The types of the switch tube Q1 and the switch tube Q2 include but are not limited to MOS tubes, IGBTs, bipolar transistors, silicon carbide and gallium nitride, and the switch tube Q3 is a diode, or the switch tube Q1 and the switch tube Q2 are diodes, and the types of the switch tube Q3 include but are not limited to MOS tubes, IGBTs, bipolar transistors, silicon carbide and gallium nitride.

6. A DCDC circuit topology structure according to claim 1, characterized in that: The port VBAT+ is connected to one end of the capacitor C5, and the other end of the capacitor C5 is connected to the port VBAT- and the port AGND.

7. A DCDC circuit topology structure according to claim 1, characterized in that: The transformer assembly includes a plurality of transformers.

8. A DCDC circuit topology structure according to claim 1, characterized in that: The transformer assembly includes a transformer T1, the other end of the capacitor C3 is connected to pin 1 of the transformer T1, pin 2 of the transformer T1 is connected to pin 3 of the transformer T1 and the other end of the switch tube Q1, pin 4 of the transformer T1 is connected to the other end of the capacitor C4, pin 5 of the transformer T1 is connected to one end of the switch tube Q3, pin 6 of the transformer T1 is connected to port VBAT+, pin 1 and pin 2 of the transformer T1 share a coil, pin 3 and pin 4 of the transformer T1 share a coil, and pin 5 and pin 6 of the transformer T1 share a coil.

9. A DCDC circuit topology structure according to claim 1, characterized in that: The other end of the capacitor C3 is connected to one end of the inductor L3, the other end of the inductor L3 is connected to one end of the inductor L4 and port 2 on the front side of the transformer assembly, and the other end of the inductor L4 is connected to the other end of the capacitor C4.

10. A DCDC circuit topology structure according to claim 1, characterized in that: The switch tube Q1, the switch tube Q2 and the switch tube Q3 are all MOS tubes, the drain of the switch tube Q1 is connected to the other end of the inductor L1, the source of the switch tube Q1 is connected to the drain of the switch tube Q2, the source of the switch tube Q2 is connected to the other end of the inductor L2, the drain of the switch tube Q3 is connected to port 2 on the rear side of the transformer component, and the source of the switch tube Q3 is connected to the port VBAT-.

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