A dual buck-boost conversion device

Abstract

The application provides a double Buck-Boost conversion device, which comprises a circuit board and three-phase conversion units arranged on the circuit board, the direct current side of each phase conversion unit is connected with a direct current source, and the alternating current side of each phase conversion unit is connected with a three-phase alternating current source; the circuit board is divided into three types of regions according to dv / dt, and the signal lines of bus capacitors, switch units, alternating current inductors and filter capacitors and other devices are divided into dynamic signals and static signals according to the type of emitted signals, and then the signal lines are routed on the static region, the dynamic region and the dynamic-static combined region of the circuit board, so that the layout of the conversion circuit is optimized, the interlayer parasitic capacitance is reduced, and the electromagnetic radiation is optimized.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of circuit, in particular to a double Buck-Boost conversion device. BACKGROUND

[0002] The development of new power systems puts forward higher requirements for conversion circuits such as inverter circuits, rectifier circuits and auxiliary source circuits, but in the related technology, the electromagnetic environment of the conversion circuit is very complex, resulting in poor electromagnetic compatibility (EMC). SUMMARY

[0003] The double Buck-Boost conversion device provided by the embodiments of the present disclosure comprises a circuit board and three-phase conversion units arranged on the circuit board, the first DC side of each phase conversion unit is connected to a DC source, and the second DC side of each phase conversion unit is connected to a three-phase DC source; the conversion unit comprises a first DC branch, a switch bridge arm and a second DC branch; the first DC branch connected to the DC source is provided with a first filter capacitor, a second filter capacitor, a first DC inductor and a second DC inductor, wherein the first filter capacitor and the second filter capacitor are connected in series across the DC source, and the first DC inductor and the second DC inductor are connected across the DC source; the switch bridge arm comprises four first, second, third and fourth switch units connected in series; the second DC branch is provided with a first bus capacitor and a second bus capacitor connected in series, and the midpoints of the first bus capacitor and the second bus capacitor are connected to the midpoints of the second switch unit and the third switch unit, and the other ends of the first bus capacitor and the second bus capacitor are respectively connected to one end of the first switch unit and one end of the fourth switch unit; the midpoints of the first switch unit and the second switch unit are connected to the other end of the first DC inductor, and the midpoints of the third switch unit and the fourth switch unit are connected to the other end of the second DC inductor; the circuit board comprises a static area, a dynamic area and a dynamic-static combination area, and the circuit board comprises a plurality of layers of boards; the projection of the static area on the plurality of layers of boards in the circuit board along a first direction only comprises static signal lines for transmitting static signals; the projection of the dynamic area on the plurality of layers of boards in the circuit board along the first direction only comprises dynamic signal lines for transmitting dynamic signals; the dynamic-static combination area on the top layer of the circuit board is provided with the switch bridge arm, wherein the first to fourth switch units are dynamic-static signal combination devices and are arranged adjacent to the static area; wherein the static signal refers to a signal with a voltage change rate close to 0, the dynamic signal refers to a signal with a voltage change rate much greater than 0, and the first direction is perpendicular to the direction of the board surface of the circuit board.

[0004] 2. The conversion device according to claim 1, wherein the bus capacitor is a device for generating only static signals, and is arranged on the static area and adjacent to the first to fourth switch units.

[0005] In some embodiments, the dynamic-static combination area comprises a large sub-area and a small sub-area, the switch bridge arm is arranged on the large sub-area, the filter capacitor is a device for generating a static signal, the filter capacitors of the three-phase conversion units form a three-phase filter capacitor group and are arranged on the small sub-area, the small sub-area is adjacent to the dynamic area, and the large sub-area, the small sub-area and the dynamic area are arranged in the second direction, and the first direction and the second direction are perpendicular to each other.

[0006] In some embodiments, the first DC inductor and the second DC inductor are devices for generating dynamic-static signal combinations, the dynamic area has three sub-dynamic areas corresponding to the single-phase conversion units, the three sub-dynamic areas are arranged in the third direction of the circuit board, and the AC inductor of each single-phase conversion unit is arranged in the sub-dynamic area thereof, and the second direction and the third direction are perpendicular to each other.

[0007] In some embodiments, the circuit board has a plurality of sub-static areas and a plurality of large sub-areas arranged in the third direction, the single-phase conversion unit has a positive bus capacitor group and a negative bus capacitor group, the positive bus capacitor group and the negative bus capacitor group are arranged in a sub-static area respectively, the switch bridge arm of the single-phase conversion unit is arranged in a large sub-area, the switch bridge arm is arranged between the positive bus capacitor group and the negative bus capacitor group, and the positive bus capacitor group and the negative bus capacitor group are dispersedly arranged.

[0008] In some embodiments, in the dynamic-static combination area, a plurality of layers in the circuit board are divided into a static layer, a dynamic layer and a shielding layer; a static signal line for transmitting the static signal is arranged in the static layer; a dynamic signal line for transmitting the dynamic signal is arranged in the dynamic layer; and the shielding layer is arranged between the static layer and the dynamic layer.

[0009] In some embodiments, the circuit board has a six-layer structure, and from bottom to top in the first direction, there are two static layers, one shielding layer and three dynamic layers.

[0010] In some embodiments, the two static layers are a BUS+ layer at the lower layer and a BUS- layer at the upper layer respectively, and the shielding layer is an internal signal N layer.

[0011] In some embodiments, the input signal lines of the first to fourth switch units are static signal lines, and the output signal lines thereof are dynamic signal lines, the static signal lines are connected with the bus capacitors of the static area through the static layer, and the dynamic signal lines are connected with the AC inductors through the dynamic layer.

[0012] From the above description of the present application and its preferred embodiments, it can be seen that, compared with the prior art, the technical scheme of the present application and its preferred embodiments have the following beneficial effects by adopting the following technical means:

[0013] In the technical solution one, the circuit board is divided into three types of regions according to dv / dt, and each device is distributed and arranged according to the type of the transmitted signal, so as to reduce the interlayer parasitic capacitance and optimize the electromagnetic compatibility.

[0014] In the technical solution two, the positive and negative bus capacitors are dispersedly placed to preferentially reduce the Loop3 loop and reduce the high-frequency current loop, so as to optimize the electromagnetic compatibility.

[0015] In the technical solution three, the three-phase filter capacitor module is arranged between the large partition and the dynamic region, so as to reduce the Loop2 loop and reduce the medium-frequency current loop, so as to optimize the electromagnetic compatibility. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A three-type current loop schematic diagram provided for the embodiment of the present disclosure;

[0017] Figure 2 A dynamic and static signal region division schematic diagram provided for the embodiment of the present disclosure;

[0018] Figure 3 A composition structure schematic diagram of a transformation circuit provided for the related art;

[0019] Figure 4 A Loop3 loop schematic diagram provided for the embodiment of the present disclosure;

[0020] Figure 5 A Loop2 loop schematic diagram provided for the embodiment of the present disclosure; DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present disclosure will be described clearly and completely in combination with the drawings in the embodiments of the present disclosure. It can be understood that the specific embodiments described herein are only used to explain the related application, and are not intended to limit the present disclosure. In addition, it should be noted that, for the purpose of description, only the parts related to the application are shown in the drawings.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. The terms used herein are only for the purpose of describing the embodiments of the present disclosure, and are not intended to limit the present disclosure.

[0023] In the following description, “some embodiments” are described, which describe a subset of all possible embodiments, but it can be understood that “some embodiments” can be the same subset or different subsets of all possible embodiments, and can be combined with each other without conflict.

[0024] It should be noted that the terms "first", "second", and "third" in the embodiments of the present disclosure are only to distinguish similar objects, and do not represent a specific order of the objects. Understandably, the "first", "second", and "third" can be interchanged in a specific order or sequence as allowed, so that the embodiments of the present disclosure described herein can be implemented in an order other than that illustrated or described herein.

[0025] In the inverter formed by the conversion circuit, the EMC needs to meet the industry-related FCC Class A standard. In the high power level, radiation is often a large number of test items. In the related art, EMC is often exceeded, and electromagnetic radiation can reach 70 decibels (dB).

[0026] Referring to Figure 1 , a three-phase current circuit schematic diagram provided by an embodiment of the present disclosure is shown. In this embodiment, the direct current end of the double Buck-Boost circuit is directly connected to an external battery, and the alternating current end is connected to a load in grid-connected or off-grid mode. In addition, the double Buck-Boost circuit system is a N-free system, and in Figure 1 , two other phases during operation are omitted, as shown in Figure 1 , an embodiment of the present disclosure provides a three-phase conversion unit including a plurality of circuit boards and three-phase conversion units, the first direct current side of each phase conversion unit is connected to a direct current source, and the second direct current side is connected to a three-phase direct current source, respectively. The conversion unit includes a first direct current branch, a switch bridge arm, and a second direct current branch. The first direct current branch connected to the direct current source is provided with a first filter capacitor 141, a second filter capacitor 142, a first direct current inductor 131, and a second direct current inductor 132. The first filter capacitor 141 and the second filter capacitor 142 are connected in series across the direct current source, and the first direct current inductor 131 and the second direct current inductor 132 are connected across the direct current source. The switch bridge arm includes four first switch units 121, second switch units 122, third switch units 123, and fourth switch units 124 connected in series with each other. The second direct current branch is provided with a first bus capacitor 111 and a second bus capacitor 112 connected in series, and the midpoints of the two are connected to the midpoints of the second switch unit 122 and the third switch unit 123. The other ends of the first bus capacitor 111 and the second bus capacitor 112 are respectively connected to one end of the first switch unit 121 and the fourth switch unit 124. The midpoints of the first switch unit 121 and the second switch unit 122 are connected to the other end of the first direct current inductor 131, and the midpoints of the third switch unit 123 and the fourth switch unit 124 are connected to the other end of the second direct current inductor 132.

[0027] Wherein, each conversion unit forms a commutation current, a ripple current and a load current in the conversion process and forms three types of current loops, such as a commutation current loop, a load current loop and a ripple current loop. Specifically, in the discharge state, during the positive half cycle, the commutation current flows through the first switching unit 121, the second switching unit 122 and the first bus capacitor 111. The ripple current flows through a first path and a second path, the first path flows through the first switching unit 121, the second switching unit 122 and the first bus capacitor 111; the second path flows through the first bus capacitor 111, the first filter capacitor 141, the first DC inductor 131 and the first switching unit 121. The load current flows through the same path as the ripple current, so it is not described again.

[0028] In addition, the above embodiment only takes the current flow in the positive half cycle in the discharge state as an example, and those skilled in the art can uniquely and unambiguously derive the current flow direction in other conversion processes, such as the current flow direction in the negative half cycle in the discharge state and the current flow direction in the positive and negative half cycles in the charging state, in combination with the above disclosure. In order to save space, it is not described again.

[0029] In summary, in the entire conversion process of the conversion unit, each of the first bus capacitor 111, the second bus capacitor 112, the first switching unit 121, the second switching unit 122, the third switching unit 123 and the fourth switching unit 124 is adapted to pass through the commutation current. Each of the first bus capacitor 111, the second bus capacitor 112, the first switching unit 121, the second switching unit 122, the third switching unit 123 and the fourth switching unit 124, the first bus capacitor 141, the second bus capacitor 142, the first DC inductor 131 and the second DC inductor 132 is adapted to pass through the ripple current.

[0030] The inventors of the present patent have found through a large number of experiments that in the above three current loops:

[0031] The load current loop Loop1 is formed by the battery DC, the bus electrolytic capacitor fundamental component and the load current. The main wave component of the current is a sine wave with a frequency of 50 Hz and its multiple frequencies. There are also a small amount of ripple after power topology and parallel machine inductance LC filtering, and radiation signals received in the machine space. The signals are input and output signals, and the characteristic is that the loop is exposed outside the machine and can be directly monitored by the Line Impedance Stabilization Network (LISN) circuit. The leakage of the switching ripple has a greater impact on the conducted test, with a frequency of 16.2 kHz and its multiple frequencies, so the AC outlet needs to be differentially filtered. The emission signals and leakage ripple signals received in the space through the loop wiring are emitted outside the machine.

[0032] Loop2, the current main wave component is a triangular wave, flowing through the inductance and the grid side filter capacitor; the signal is the largest power in the machine, the frequency is 16.2 kHz and its multiple frequency. In addition, as shown in Figure 1 Loop2.

[0033] Loop3, the current main wave component is a sharp impulse waveform, mainly through the vertical pipe and the horizontal pipe to open and off, the frequency is 1-10 MHz and its multiple frequency, depending on the opening and off speed of the tube; the signal is characterized by the highest frequency, and the frequency content is very rich.

[0034] Considering Figure 1 Loop1, the signal emission and propagation path of Loop2 and Loop3 are more. Therefore, the embodiment adopts the technical means of reducing the loop to improve electromagnetic compatibility, and the specific means is that each of the conversion units forms a commutation current, a ripple current and a load current in the conversion process; in the entire conversion process of the conversion unit, the first bus capacitor 111, the second bus capacitor 112, the first switch unit 121, the second switch unit 122, the third switch unit 123 and the fourth switch unit 124 are adapted to pass through the commutation current. Each device adapted to pass through the commutation current is configured on the same first circuit board. It should be noted that in the embodiment, each device passing through the ripple current and the commutation current is integrated on the same first circuit board, but actually the double Buck-Boost conversion device is not composed of only one circuit board. Such a setting is mainly considering that the main influencing factor of the high-frequency current loop is the current change rate (di / dt), the higher the current change rate, the higher the frequency, and the easier the emission, therefore, by reducing the area of the high-frequency current loop, the electromagnetic wave emitted to the outside can be reduced, thereby reducing the electromagnetic interference and optimizing the electromagnetic compatibility.

[0035] In addition, the first bus capacitor 111, the second bus capacitor 112, the first switch unit 121, the second switch unit 122, the third switch unit 123, and the fourth switch unit 124, the first bus capacitor 141, the second bus capacitor 142, the first direct-current inductor 131, and the second direct-current inductor 132 are adapted to pass the ripple current, and in the case that the first circuit board has sufficient area, the ripple current AC inductor and filter capacitor can also be arranged on the first circuit board, so that the area of the medium-frequency and high-frequency current loop is reduced, and the electromagnetic compatibility is improved. In the case that the first circuit board has insufficient area, the first bus capacitor 141, the second bus capacitor 142, the first direct-current inductor 131, and the second direct-current inductor 132 that are irrelevant to the high-frequency current loop are arranged on the same second circuit board through repeated verification, so that the area of the high-frequency current loop is controlled to the maximum extent, the area of the medium-frequency loop is taken into account, and the layout space and cost are fully considered, the electromagnetic interference is also reduced, and good electromagnetic compatibility is achieved.

[0036] Referring to Figure 2 It shows a dynamic and static signal region diagram provided by an embodiment of the present disclosure. As shown in Figure 2 The first circuit board includes a static region 31, a dynamic region 32, and a dynamic and static combination region 33, and the first circuit board includes a multi-layer board Figure 2 Only the labels 31, 32, and 33 are marked, and the remaining static region, dynamic region, and dynamic and static combination region are not marked, for example, the PCB includes a 6-layer board, and the static region is projected on the 6 layers of the PCB without other signals; the solid line box region is the static region 31, and the static signal can include BUS+ and BUS- signals, which are directly connected to the battery outside the machine; the dashed line box is the dynamic region 32, and the dynamic signal can include INVA, INVB, and INVC signals before the inverter inductor; the dotted line box is the dynamic and static combination region 33, i.e., a region in which the dynamic and static signals cannot be separated, and the signals in the dynamic and static combination region are mainly various signals connected to the switch unit.

[0037] In some embodiments, in the dynamic and static combination region 33, the multi-layer board in the first circuit board includes a static layer, a dynamic layer, and a shielding layer; the static layer includes a static signal line for transmitting a static signal, the dynamic layer includes a dynamic signal line for transmitting a dynamic signal; and the shielding layer is distributed between the static layer and the dynamic layer.

[0038] Exemplarily, the first circuit board includes a 6-layer board, and in the dynamic-static combination area, the 6-layer board is divided into a top 3-layer and a bottom 2-layer. Among them, the top 3-layer is a dynamic layer for transmitting dynamic signals, and the bottom 2-layer is a static layer for transmitting static signals such as BUS+ and BUS-. The middle layer is a shielding layer, which is separated by an internal signal N layer. Specifically, the 1st layer (Top layer) can be a dynamic layer and a driving layer such as INVA, INVB, INVC, the 2nd layer (Midlayer1) can be a dynamic layer such as INVA, INVB, INVC, the 3rd layer (Midlayer2) can be a dynamic layer such as INVA, INVB, INVC, the 4th layer (Midlayer3) can be an internal virtual N layer, the 5th layer (Midlayer4) can be a main BUS- layer, and the 6th layer (Bottom layer) can be a main BUS+ layer.

[0039] Referring again to Figure 2 On the first circuit board, four sub-static areas are arranged along the third direction, which are respectively a first sub-static area 311, a second sub-static area 312, a third sub-static area 313, and a fourth sub-static area 314; three large areas are arranged along the third direction on the first circuit board, which are respectively a first large area 331, a second large area 332, and a third large area 333; three sub-dynamic areas are arranged along the third direction on the first circuit board, which are respectively a first sub-dynamic area 321, a second sub-dynamic area 322, and a third sub-dynamic area 323. The large areas and the sub-dynamic areas are arranged along the second direction on the first circuit board, and the second direction is perpendicular to the third direction.

[0040] The switch bridge arms of the three-phase conversion unit are respectively an A-phase switch bridge arm 2111, a B-phase switch bridge arm 2112, and a C-phase switch bridge arm 2113, wherein the A-phase switch bridge arm 2111 is arranged in the first large area 331, the B-phase switch bridge arm 2112 is arranged in the second large area 332, and the C-phase switch bridge arm 2113 is arranged in the third large area 333.

[0041] The bus capacitor is a device that only generates static signals, and the bus capacitor of the three-phase conversion unit is divided into a positive bus capacitor group 2121, a positive bus capacitor group 2123, a negative bus capacitor group 2122, and a negative bus capacitor group 2124. The positive bus capacitor group 2121 is arranged in the first sub-static area 311, the negative bus capacitor group 2122 is arranged in the second sub-static area 312, the positive bus capacitor group 2123 is arranged in the third sub-static area 313, and the negative bus capacitor group 2124 is arranged in the fourth sub-static area 314.

[0042] The first direct-current inductor and the second direct-current inductor are dynamic-static signal combination devices, the dynamic region has three sub-dynamic regions corresponding to the three single-phase conversion units, the three sub-dynamic regions are arranged at intervals in the third direction of the first circuit board, the A-phase alternating-current inductors are respectively arranged on the periphery of the first sub-dynamic region 321, the B-phase alternating-current inductors are respectively arranged on the periphery of the second sub-dynamic region 322, and the C-phase alternating-current inductors are respectively arranged on the periphery of the third sub-dynamic region 323. Corresponding to each sub-dynamic region is a dynamic signal line connected with the alternating-current inductor.

[0043] The filter capacitor is a device for generating a static signal, and the dynamic-static combination region further has a small sub-region 334. The filter capacitors of the three-phase conversion units form a three-phase filter capacitor module and are arranged on the small sub-region 334. The small sub-region 334 is adjacent to the dynamic region, and the large sub-region and the small sub-region are arranged at intervals in the second direction. In this embodiment, the three-phase filter capacitor module is arranged between the large sub-region and the dynamic region, thereby reducing the Loop2 loop and the intermediate frequency current loop, and thus optimizing electromagnetic compatibility.

[0044] Taking the A-phase switch bridge arm as an example, the first switch unit 121 to the fourth switch unit 124 are dynamic-static signal combination devices. The first switch unit 121 and the second switch unit 122 are arranged close to the first sub-static region 311, and the third switch unit 123 and the fourth switch unit 124 are arranged close to the second sub-static region 312. For specific signal line arrangement, the first switch unit 121 is taken as an example. The static signal line of the first switch unit 121 is connected with the positive bus capacitor group 2121 through the static layer of the first large sub-region 331 where the first switch unit 121 is located. The dynamic signal line of the first switch unit 121 is connected with the second switch unit 122 through the dynamic layer of the first large sub-region 331 where the first switch unit 121 is located. The dynamic signal line of the first switch unit 121 is further connected with the first direct-current inductor and the second direct-current inductor of the A-phase through the dynamic layer of the first large sub-region 331 where the first switch unit 121 is located and the dynamic layer of the small sub-region 334.

[0045] It should be noted that the static signal refers to a signal with constant or almost constant voltage, and the dynamic signal refers to a signal with large voltage change. The specific numerical value of the voltage change rate of the static signal and the dynamic signal is not specifically limited, but the voltage change rate of the dynamic signal is greater than that of the static signal.

[0046] It should be noted that the specific number of the multiple layers included in the first circuit board, and the specific number of the static layers and the dynamic layers are not specifically limited, but the multiple static layers are arranged adjacent to each other, and the multiple dynamic layers are arranged adjacent to each other.

[0047] It should be further noted that the dynamic layer, the shielding layer and the static layer can be arranged on the first circuit board from top to bottom along the third direction, or can be arranged on the first circuit board from bottom to top along the third direction, which can be selected according to actual conditions.

[0048] Further, in some embodiments, when the projection of the signal line transmitting the static signal along the third direction of the multi-layer board in the first circuit board does not overlap with the projection of the signal line transmitting the dynamic signal along the third direction of the multi-layer board in the first circuit board, the multi-layer board in the first circuit board comprises a static layer and a dynamic layer;

[0049] When the projection of the signal line transmitting the static signal along the third direction of the multi-layer board in the first circuit board overlaps with the projection of the signal line transmitting the dynamic signal along the third direction of the multi-layer board in the first circuit board, the multi-layer board in the first circuit board comprises a static layer, a dynamic layer and a shielding layer, and the shielding layer is distributed between the static layer and the dynamic layer.

[0050] That is, in the pure static area and the pure dynamic area, the first circuit board is also a multi-layer board, but because the same kind of signal is transmitted respectively, no shielding layer is needed in the middle; and in the dynamic-static combination area, because the static signal and the dynamic signal need to be transmitted, a shielding layer needs to be added in the middle to shield, so as to realize the separation of the dynamic signal and the static signal.

[0051] In summary, the embodiments of the present disclosure provide a double Buck-Boost conversion device, which divides the first circuit board into three types of areas according to dv / dt, and divides the signal lines of each device into dynamic signal and static signal areas (i.e., static area, dynamic area and dynamic-static combination area) and layers (i.e., static layer, dynamic layer and shielding layer) according to the type of transmitted signal; thereby optimizing the layout of the conversion circuit to optimize electromagnetic radiation.

[0052] In a preferred embodiment, as shown in Figure 2 , the positive bus capacitor and the negative bus capacitor are dispersedly placed, and this arrangement is mainly considered for:

[0053] Referring to Figure 3 , a composition structure schematic diagram of a conversion circuit provided by the related art is shown, which is specifically the layout of a switching unit a1, a bus capacitor a2, a filter capacitor a3 and a current sampling element a4 in the related art. As shown in Figure 3 , the switching unit a1 and the bus capacitor a2 are located on one circuit board, the filter capacitor a3 is located on another circuit board, and the current sampling element a4 is located on another circuit board, that is, the switching unit and the bus capacitor, the filter capacitor and the current sampling element are respectively distributed on three circuit boards, and the span is large. In addition, the bus capacitor a2 is centrally placed.

[0054] After the high-frequency current loop is formed by the arrangement of the devices, it is necessary to control Figure 1The Loop2 loop and the Loop3 loop shown are minimum, but the size of the Loop2 loop and the Loop3 loop is contradictory. If the bus capacitor is placed dispersedly, the Loop3 loop of each phase is relatively small, and the Loop2 loop is relatively large. If the bus capacitor is placed concentratedly, the Loop3 loop of each phase is relatively large, and the Loop2 loop is relatively small.

[0055] Specifically, the frequency of the signal in the Loop2 loop is 16.2 kHz and its multiple frequencies, at which the inductive reactance of the wiring in the circuit board is small. The frequency of the signal in the Loop3 loop is about 5 MHz, which is larger than 16.2 kHz, so the inductive reactance of the wiring in the circuit board is large. Therefore, for the Loop2 loop, the position of the bus capacitor has little effect. Regardless of where the bus capacitor is placed, the current will flow to the capacitor. For the Loop3 loop, the current will flow to the nearest capacitor first. If the positive bus capacitor and the negative bus capacitor are placed concentratedly, the Loop2 loop is small, but the Loop3 loop is large, so as shown in FIG. 4, the positive bus capacitor and the negative bus capacitor are placed dispersedly. Figure 2

[0056] The size of the Loop2 loop and the Loop3 loop needs to be traded off. Because the present disclosure has a high requirement on the stress of the switching unit and the capacitor is not easy to be concentrated due to the space limitation, the Loop3 loop is preferentially reduced. As shown in FIG. 5, the Loop3 loop is greatly affected by the impedance (position) on the board, and the capacitance value is required to be low, so the shunt on the board is relatively weak, and the loop is more concentrated. As shown in FIG. 6, the Loop2 loop is less affected by the impedance (position) on the board, and is more affected by the capacitance value, so the loop is inevitably more dispersed. In addition, Figure 4 Figure 5 Figure 4 and Figure 5 are abstracted schematic diagrams for illustrating the relative size of the Loop2 loop and the Loop3 loop, and some devices are omitted. In summary, in the embodiment, the positive bus capacitor and the negative bus capacitor are placed dispersedly, so that the Loop3 loop is preferentially reduced, the high-frequency current loop is further reduced, and the electromagnetic compatibility is optimized.

[0057] Those skilled in the art can understand that, in other embodiments, the bus capacitors of the three-phase conversion unit can be six groups (that is, there is no multiplexing of the positive bus capacitor and the negative bus capacitor for each phase), and the corresponding static separation zones are six. In addition, in the arrangement relationship between the switching bridge arms and the corresponding positive bus capacitor and negative bus capacitor groups, in addition to the above-mentioned linear arrangement, the switching bridge arms can also be linearly arranged, the positive bus capacitor group and the negative bus capacitor group are linearly arranged above the switching bridge arms in the second direction, and the switching bridge arms are arranged between the positive bus capacitor group and the negative bus capacitor group. The positive bus capacitor group and the negative bus capacitor group are dispersedly placed, that is, the three are in a triangular arrangement.

[0058] ​​​The above merely describes preferred embodiments of the present disclosure, but is not intended to limit the protection scope of the present disclosure.

[0059] It should be noted that in the present disclosure, the terms "comprising", "including", or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or apparatus including a series of elements includes not only those elements, but also other elements not explicitly listed, or further includes elements inherent in such a process, method, article, or apparatus. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article, or apparatus including the element.

[0060] The above-mentioned sequence numbers of the embodiments of the present disclosure are only for description, and do not represent the advantages or disadvantages of the embodiments.

[0061] The methods disclosed in the several method embodiments provided by the present disclosure can be combined arbitrarily without conflict to obtain new method embodiments.

[0062] The features disclosed in the several product embodiments provided by the present disclosure can be combined arbitrarily without conflict to obtain new product embodiments.

[0063] The features disclosed in the several method or device embodiments provided by the present disclosure can be combined arbitrarily without conflict to obtain new method or device embodiments.

[0064] The above merely describes specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present disclosure, which should be covered within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. A dual Buck-Boost conversion device, characterized by The circuit board and three-phase conversion units arranged on the circuit board, the first DC side of each phase conversion unit is connected to a DC source, and the second DC side is connected to a three-phase DC source respectively; The conversion unit comprises a first DC branch, a switch bridge arm and a second DC branch; The first DC branch connected to the DC source is provided with a first filter capacitor, a second filter capacitor, a first DC inductor and a second DC inductor, wherein the first filter capacitor and the second filter capacitor are connected in series across the DC source, and the first DC inductor and the second DC inductor are connected across the DC source respectively; the switch bridge arm comprises four first, second, third and fourth switch units connected in series; the second DC branch is provided with a first bus capacitor and a second bus capacitor connected in series, and the midpoint of the two is connected to the midpoint of the second and third switch units, and the other end of the first and second bus capacitors is connected to one end of the first and fourth switch units respectively; the midpoint of the first and second switch units is connected to the other end of the first DC inductor, and the midpoint of the third and fourth switch units is connected to the other end of the second DC inductor; The circuit board comprises a static area, a dynamic area and a dynamic-static combination area, and the circuit board comprises a plurality of layers; The projection of the static area on the plurality of layers in the circuit board along a first direction only comprises static signal lines for transmitting static signals; the projection of the dynamic area on the plurality of layers in the circuit board along the first direction only comprises dynamic signal lines for transmitting dynamic signals; the dynamic-static combination area on the top layer of the circuit board is provided with a switch bridge arm, wherein the first to fourth switch units are dynamic-static signal combination devices and are arranged adjacent to the static area. The static signal refers to a signal with a voltage change rate close to 0, the dynamic signal refers to a signal with a voltage change rate much greater than 0, and the first direction is perpendicular to the direction of the circuit board surface.

2. The conversion device of claim 1, wherein: The bus capacitor is a device that only generates static signals, and is arranged on the static area and adjacent to the first to fourth switch units.

3. The conversion device of claim 2, wherein: The dynamic-static combination area comprises a large partition and a small partition, the switch bridge arm is arranged on the large partition, the filter capacitor is a device that generates static signals, the filter capacitors of the three-phase conversion units form a three-phase filter capacitor group and are arranged on the small partition, the small partition is adjacent to the dynamic area, and the large partition, the small partition and the dynamic area are arranged in a second direction, and the first direction and the second direction are perpendicular to each other.

4. The conversion device of claim 3, wherein: The first DC inductor and the second DC inductor are dynamic-static signal combination devices, and the dynamic area has three sub-dynamic areas corresponding to the single-phase conversion units, the three sub-dynamic areas are arranged in a third direction of the circuit board, and the AC inductor of each phase conversion unit is arranged in the sub-dynamic area, and the second direction and the third direction are perpendicular to each other.

5. The conversion device of claim 4, wherein: The circuit board has a plurality of sub-static areas arranged in the third direction, a plurality of large partitions, the single-phase conversion unit has positive and negative bus capacitor groups, the positive and negative bus capacitor groups are arranged in a sub-static area, the switch bridge arm of the single-phase conversion unit is arranged in a large partition, and the switch bridge arm is arranged between the positive and negative bus capacitor groups, and the positive and negative bus capacitor groups are dispersed.

6. The conversion device of claim 4, wherein: in the dynamic-static combination area, the multi-layer board in the circuit board is divided into static layers, dynamic layers and a shielding layer; static signal lines transmitting the static signals are arranged in the static layers; and, dynamic signal lines transmitting the dynamic signals are arranged in the dynamic layers; and the shielding layer is arranged between the static layers and the dynamic layers. the circuit board is a six-layer board structure, in a first direction, from bottom to top, two static layers, one shielding layer and three dynamic layers.

7. The conversion device of claim 6, wherein the two static layers are a BUS+ layer at the bottom and a BUS- layer at the top, respectively, and the shielding layer is an internal signal N layer.

8. The conversion device of claim 7, wherein input signal lines of the first to fourth switch units are static signal lines, and output signal lines thereof are dynamic signal lines, the static signal lines are connected with bus capacitors in the static area through the static layers, and the dynamic signal lines are connected with alternating current inductors through the dynamic layers.

9. The conversion device of claim 6, wherein ​

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