A dual buck-boost conversion device

Abstract

This invention provides a dual BuckBoost converter, comprising several circuit boards and a three-phase converter unit. Each converter unit has its DC side connected to a DC source and its AC side connected to a three-phase AC source. By configuring the components of the first bus capacitor, second bus capacitor, first switching unit, second switching unit, third switching unit, and fourth switching unit—which carry the commutation current—on the same first circuit board throughout the entire conversion process, and by rationally partitioning the board, the mid- and high-frequency current loops are confined to a small area within the power amplifier board. Furthermore, the mid- and high-frequency current loops are shielded on the board using PCB stack-up, and dynamic and static signals are partitioned on the board. Thus, by optimizing the layout of the converter circuit, electromagnetic radiation is optimized.

Description

Technical Field

[0001] This disclosure relates to the field of circuit technology, and more particularly to a dual BuckBoost converter. Background Technology

[0002] The development of new power systems has placed higher demands on conversion circuits such as inverter circuits, rectifier circuits, and auxiliary power supply circuits. However, in related technologies, the electromagnetic environment of conversion circuits is very complex, resulting in poor electromagnetic compatibility (EMC). Summary of the Invention

[0003] This disclosure provides a dual BuckBoost converter, including several circuit boards and a three-phase conversion unit. Each conversion unit has a first DC side connected to a DC source and a second DC side connected to the three-phase DC source. Each conversion unit includes a first DC branch, a switch bridge arm, and a second DC branch. The first DC branch, connected to the DC source, includes a first filter capacitor, a second filter capacitor, a first DC inductor, and a second DC inductor. The first and second filter capacitors are connected in series across the DC source, and the first and second DC inductors are connected to the two ends of the DC source. The switch bridge arm includes four interconnected first switch units, second switch units, third switch units, and fourth switch units. The second DC branch includes a first bus capacitor and a... The second bus capacitor and the midpoint of the first bus capacitor and the second bus capacitor are connected to the midpoint 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 the fourth switch unit; the midpoint of the first switch unit and the second switch unit is connected to the other end of the first DC inductor, and the midpoint of the third switch unit and the fourth switch unit is connected to the other end of the second DC inductor; wherein, each of the conversion units generates commutation current, ripple current and load current during the conversion process; during the entire conversion process of the conversion unit, each of the first bus capacitor, the second bus capacitor, the first switch unit, the second switch unit, the third switch unit and the fourth switch unit is adapted to carry the commutation current, and each device adapted to carry the commutation current is configured to be located on the same first circuit board.

[0004] In some embodiments, each of the first filter capacitor, second filter capacitor, first DC inductor, second DC inductor, first switch unit, second switch unit, third switch unit, fourth switch unit, first bus capacitor, second bus capacitor, first DC inductor and second DC inductor is adapted to carry the ripple current, and each device adapted to carry the ripple current is configured to be located on the same first circuit board.

[0005] In some embodiments, each of the first filter capacitor, second filter capacitor, first DC inductor, second DC inductor, first switch unit, second switch unit, third switch unit, fourth switch unit, first bus capacitor, second bus capacitor, first DC inductor, and second DC inductor is adapted to carry the ripple current, wherein the first filter capacitor, second filter capacitor, first DC inductor, and second DC inductor are configured to be located on the same second circuit board.

[0006] In some embodiments, the second circuit board further includes a current sampling element, and the first filter capacitor, the second filter capacitor, and the current sampling element are distributed sequentially on the same second circuit board.

[0007] In some embodiments, the area through which the commutation current flows is defined as a first shielding area, and a first shielding layer is provided on the circuit board of the first shielding area; the area through which the ripple current flows is defined as a second shielding area, and a second shielding layer is provided on the circuit board of the second shielding area.

[0008] In some embodiments, the first shielding layer and the second shielding layer are copper-clad layers, and the copper-clad thickness of the first shielding layer is greater than that of the second shielding layer; a third shielding layer is provided in the overlapping area of ​​the first shielding region and the second shielding region, the third shielding layer is a copper-clad layer, and the copper-clad thickness of the third shielding layer is greater than that of the first shielding layer and the second shielding layer.

[0009] In some embodiments, the first circuit board includes a static area, a dynamic area, and a dynamic-static combination area, and the first circuit board includes a multilayer board;

[0010] The projection of the static zone onto the multilayer board in the first circuit board along a third direction includes only the static signal; the projection of the dynamic zone onto the multilayer board in the first circuit board along a third direction includes only the dynamic signal; the projection of the combined static and dynamic zone onto the multilayer board in the first circuit board along a third direction includes both the static signal and the dynamic signal.

[0011] Wherein, the static signal refers to a signal with a voltage change rate close to 0, and the dynamic signal refers to a signal with a voltage change rate much greater than 0; the third direction is the direction perpendicular to the surface of the first circuit board.

[0012] In some embodiments, in the static-dynamic junction area, the multilayer board in the first circuit board is divided into a static layer, a dynamic layer, and a shielding layer; signal lines for transmitting the static signal are arranged in the static layer; and signal lines for transmitting the dynamic signal are arranged in the dynamic layer; and the shielding layer is arranged between the static layer and the dynamic layer.

[0013] As can be seen from the above description of the present invention and its preferred embodiments, compared with the prior art, the technical solution of the present invention and its preferred embodiments have the following beneficial effects due to the adoption of the following technical means:

[0014] In technical solution one, considering the large amount of signal transmission and propagation paths in the ripple current loop Loop2 and the tube commutation current loop Loop3, the area of ​​the medium and high frequency current loops is reduced by integrating the devices passing through the ripple current and commutation current on the same first circuit board, thereby reducing electromagnetic interference and optimizing electromagnetic compatibility.

[0015] In technical solution two, by setting up a shielding layer, the area inside the high-frequency ring that cannot be optimized is shielded by using copper as a shielding layer. Since copper is a low conductivity material, it will generate eddy currents in the high-frequency magnetic field and thus generate a reverse magnetic field, which will cancel out part of the high-frequency magnetic field, thereby further optimizing electromagnetic compatibility.

[0016] In technical solution three, the first circuit board is divided into three types of areas based on dv / dt, and the signal lines of the devices are distributed and arranged according to the type of transmitted signal, thereby reducing the formation of interlayer parasitic capacitance and optimizing electromagnetic compatibility. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of three types of current loops provided in an embodiment of the present disclosure;

[0018] Figure 2 A schematic diagram of the composition structure of a conversion circuit provided for related technologies;

[0019] Figure 3 A schematic diagram of the composition structure of a conversion circuit provided in an embodiment of this disclosure;

[0020] Figure 4 A schematic diagram of the composition structure of a shielding region provided in an embodiment of this disclosure. Figure 1 ;

[0021] Figure 5 A schematic diagram of the composition structure of a shielding region provided in an embodiment of this disclosure. Figure 2 ;

[0022] Figure 6 This is a schematic diagram of dynamic and static signal segmentation provided in an embodiment of the present disclosure; Detailed Implementation

[0023] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for explaining the relevant applications and are not intended to limit the scope of this disclosure. Furthermore, it should be noted that, for ease of description, only the parts relevant to the relevant applications are shown in the accompanying drawings.

[0024] 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 this disclosure belongs. The terminology used herein is for the purpose of describing embodiments of this disclosure only and is not intended to be limiting of this disclosure.

[0025] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0026] It should be noted that the terms "first, second, third" used in the embodiments of this disclosure are merely to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first, second, third" can be interchanged in a specific order or sequence where permitted, so that the embodiments of this disclosure described herein can be implemented in an order other than that illustrated or described herein.

[0027] In inverters formed by conversion circuits, EMC must comply with the relevant FCC Class A standards. In high-power applications, radiation is often a major test item that exceeds the limits. In related technologies, EMC exceedances are frequent, with electromagnetic radiation reaching 70 dB.

[0028] See Figure 1 This illustration shows a schematic diagram of three types of current loops provided in an embodiment of this disclosure. In this embodiment, the DC terminal of the dual BuckBoost circuit is directly connected to the external battery, and the AC terminal is connected to the load either in parallel with or off-grid. Furthermore, this dual BuckBoost circuit system is an N-less system. Figure 1 The other two phases are omitted during operation, such as Figure 1As shown, this embodiment of the disclosure provides a series of circuit boards and a three-phase conversion unit. Each conversion unit has a first DC side connected to a DC source and a second DC side connected to a three-phase DC source. The conversion unit includes a first DC branch, a switch bridge arm, and a second DC branch. The first DC branch, connected to the DC source, includes a first filter capacitor 141, a second filter capacitor 142, a first DC inductor 131, and a second DC inductor 132. The first filter capacitor 141 and the second filter capacitor 142 are connected in series across the DC source, and the first DC inductor 131 and the second DC inductor 132 are respectively connected across the two ends of the DC source. The switch bridge arm includes four first switch bridge arms connected in series. The circuit includes a first switch unit 121, a second switch unit 122, a third switch unit 123, and a fourth switch unit 124. The second DC branch is provided with a first bus capacitor 111 and a second bus capacitor 112 connected in series, and the midpoint of the two is connected to the midpoint 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 midpoint of the first switch unit 121 and the second switch unit 122 is connected to the other end of the first DC inductor 131, and the midpoint of the third switch unit 123 and the fourth switch unit 124 is connected to the other end of the second DC inductor 132.

[0029] Each conversion unit generates commutation current, ripple current, and load current during the conversion process, forming three types of current loops: commutation current loop, load current loop, and ripple current loop. Specifically, during the positive half-cycle of the conversion device in the discharge state: 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 two paths: 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 will not be described further.

[0030] Furthermore, the above embodiments only take the current flow of the positive half-axis in the discharge state as an example. Those skilled in the art, in conjunction with the above disclosure, can uniquely and unambiguously deduce the direction of current flow in the negative half-cycle in other transformation processes, such as in the discharge state and in the charging state, the direction of current flow in the positive and negative half-cycles. To save space, these will not be elaborated further.

[0031] In summary, throughout the entire conversion process of the conversion unit, each of the first bus capacitor 111, second bus capacitor 112, first switching unit 121, second switching unit 122, third switching unit 123, and fourth switching unit 124 is adapted to carry the commutation current. Each of the first bus capacitor 111, second bus capacitor 112, first switching unit 121, second switching unit 122, third switching unit 123, and fourth switching unit 124, first bus capacitor 141, second bus capacitor 142, first DC inductor 131, and second DC inductor 132 is adapted to carry the ripple current.

[0032] Through extensive experimentation, the inventors of this patent discovered that in the above three current circuits:

[0033] The load current loop, Loop 1, is formed by the battery DC current, the fundamental component of the bus electrolytic capacitor, and the load current. The main waveform of this current is a sine wave with a frequency of 50 Hz and its harmonics. It also includes minor ripple from the power topology and LC filtering by the parallel inductor, as well as radiated signals received by the traces within the machine. These signals are both input and output signals. A key feature is that the loop is exposed externally and can be directly monitored by the Line Impedance Stabilization Network (LISN) circuit. The leakage of the switching ripple has a significant impact on conducted tests, with a frequency of 16.2 kHz and its harmonics; therefore, differential-mode filtering is required at the AC output. The transmitted signals and leakage ripple signals received by this loop in the machine will be transmitted externally through the loop traces.

[0034] The ripple current loop (Loop 2) has a predominantly triangular waveform, flowing through an inductor and a grid-side filter capacitor. This signal is the highest power mid-to-high frequency signal within the machine, with a frequency of 16.2kHz and its harmonics. Additionally, as... Figure 1 As shown, the INVA signal is the signal itself in the Loop2 loop.

[0035] The commutation current loop Loop3 has a current waveform mainly composed of spike impulse waveforms, which are formed by the switching on and off of the vertical and horizontal tubes, with frequencies ranging from 1 to 10 MHz and their harmonics, depending on the switching on and off speeds of the tubes. This signal is characterized by its high frequency and rich frequency content.

[0036] Considering Figure 1The load current loop Loop 1 shown has more interference, while the ripple current loops Loop 2 and Loop 3 have more signal transmission and propagation paths. Therefore, this embodiment uses loop reduction techniques to improve electromagnetic compatibility. Specifically, each of the conversion units generates commutation current, ripple current, and load current during the conversion process. Throughout the conversion process of the conversion unit, each of the first bus capacitor 111, second bus capacitor 112, first switching unit 121, second switching unit 122, third switching unit 123, and fourth switching unit 124 is adapted to carry the commutation current. The devices adapted to carry the commutation current are configured to be located on the same first circuit board. It should be noted that in this embodiment, the devices carrying the ripple current and commutation current are integrated on the same first circuit board, but in reality, the dual BuckBoost converter is not composed of only one circuit board. This configuration is mainly based on the fact that the main influencing factor of the high-frequency current loop is the rate of change of current (di / dt). The higher the rate of change of current, the higher the frequency, and the easier it is to transmit. Therefore, by reducing the area of ​​the high-frequency current loop, the electromagnetic waves transmitted to the outside can be reduced, thereby reducing electromagnetic interference and optimizing electromagnetic compatibility.

[0037] Furthermore, each of the first bus capacitor 111, second bus capacitor 112, first switch unit 121, second switch unit 122, third switch unit 123, and fourth switch unit 124, first bus capacitor 141, second bus capacitor 142, first DC inductor 131, and second DC inductor 132 is adapted to carry the ripple current. If the area of ​​the first circuit board is sufficient, the AC inductor and filter capacitor adapted to carry the ripple current can also be placed together on the first circuit board, thereby reducing the area of ​​the intermediate frequency and high frequency current loops and improving electromagnetic compatibility. Considering the insufficient area of ​​the first circuit board, through repeated verification, the first bus capacitor 141, second bus capacitor 142, first DC inductor 131, and second DC inductor 132, which are not related to the high frequency current loop, are arranged on the same second circuit board. This maximizes the control of the area of ​​the high frequency current loop, takes into account the area of ​​the intermediate frequency loop, fully considers layout space and cost, reduces electromagnetic interference, and has good electromagnetic compatibility.

[0038] See Figure 2 It shows a schematic diagram of the composition structure of a conversion circuit provided by related technology, specifically the layout of the switching unit a1, bus capacitor a2, filter capacitor a3, and current sampling element a4 in the related technology. Figure 2As shown, 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. In other words, the switching unit, the bus capacitor, the filter capacitor, and the current sampling element are distributed on three circuit boards, which is quite a large span.

[0039] See Figure 3 This figure illustrates a method of arranging the three-phase conversion unit on a first circuit board according to an embodiment of this disclosure: the switching arms of the three-phase conversion unit are A-phase switching arm 2111, B-phase switching arm 2112, and C-phase switching arm 2113, and the three-phase switching arms are distributed in a first direction. The bus capacitors of the three-phase conversion unit are divided into A-phase bus capacitor group 2121, B-phase bus capacitor group 2122, and C-phase bus capacitor group 2123, and the three bus capacitor groups are arranged in a first direction. The filter capacitors of the three-phase conversion unit constitute a three-phase filter capacitor module 213, which is disposed on one side of the switching arm and arranged adjacent to the switching arm in a second direction; the AC inductors 214 of the three-phase conversion unit are spaced apart on one side of the three-phase filter capacitor module 213 in the first direction of the first circuit board and arranged adjacent to the three-phase filter capacitor module 213 in the second direction, with the first direction and the second direction being perpendicular to each other.

[0040] Experiments have shown that, in related technologies, the loop area of ​​the ripple current loop Loop2 (i.e., the medium-to-high frequency current loop) is approximately 180,741 square millimeters (mm²). 2 In this disclosure, by arranging multiple target devices on the same first circuit board, the loop area of ​​the mid-to-high frequency current loop is reduced to approximately 26796 mm². 2 In other words, different board partitioning strategies can lead to significant differences in the loop area of ​​mid-to-high frequency current loops, thereby optimizing electromagnetic compatibility.

[0041] In a preferred embodiment, a shielding layer can also be used to address the unoptimizable mid- and high-frequency loop area. Copper plating can be used as a shielding layer because copper is a low-conductivity material; it generates eddy currents in high-frequency magnetic fields, which in turn generate a reverse magnetic field, offsetting part of the high-frequency magnetic field and further optimizing electromagnetic compatibility. Specifically, the area through which the commutation current flows is defined as the first shielding area, and a first shielding layer is provided on the first circuit board within the first shielding area. The area through which the ripple current flows is defined as the second shielding area, and a second shielding layer is provided on the first circuit board within the second shielding area. A third shielding layer is provided in the overlapping area of ​​the first and second shielding areas. The first, second, and third shielding layers are copper plating layers.

[0042] See details. Figure 4 This illustrates a schematic diagram of the composition structure of a shielding region provided in an embodiment of this disclosure. For example... Figure 4 As shown, the shielding area is specifically region 221 enclosed by the high-frequency signal loop, within which the high-frequency signal itself is shielded. Additionally, Figure 4 This is an abstract schematic diagram used to illustrate the location of the shielding area; some components are omitted. In some embodiments, the thickness of the copper plating on the first circuit board varies depending on the shielding area.

[0043] Specifically, the copper thickness of the first shielding layer is greater than that of the second shielding layer, and the copper thickness of the third shielding layer is greater than that of the first and second shielding layers.

[0044] It should also be noted that the layout layer used for shielding has certain requirements; generally, it uses signals that are not directly exposed to the outside world, and / or signals within high-frequency loops themselves. See [link / reference] Figure 5 It illustrates a schematic diagram of the composition structure of a shielding region provided in an embodiment of this disclosure. Figure 1 .like Figure 5 As shown, the shielding area is specifically the non-current-carrying N-line area, that is, the area 222 enclosed by the internal signal loop. The internal signals are shielded in this area. For example, the conversion circuit system of this disclosure is a battery-free neutral point and mains power-free N system. In this case, N is a completely internal machine signal and has a large number of capacitors to filter the external signal BUS+ / -, which can be used for shielding.

[0045] In summary, the shielding layer is placed in the corresponding shielding area. The size and shape of the shielding layer can be greater than, equal to or smaller than the size or shape of the shielding area, or it can be a part of the shielding area. In this way, by using copper as a shielding layer, since copper is a low conductivity material, it will generate eddy currents for high-frequency magnetic fields, thereby generating a reverse magnetic field, which will cancel out part of the high-frequency magnetic field, thus further optimizing electromagnetic compatibility.

[0046] In a preferred embodiment, the first circuit board can be further divided into three regions based on dv / dt, and the devices can be distributed and arranged according to the type of transmitted signal, thereby reducing the formation of interlayer parasitic capacitance and optimizing electromagnetic compatibility. Specifically:

[0047] See Figure 6 It illustrates a schematic diagram of dynamic and static signal segmentation provided in an embodiment of this disclosure. For example... Figure 6 As shown, the first circuit board includes a static area 31, a dynamic area 32, and a dynamic-static combination area 33, and the first circuit board includes a multilayer board ( Figure 6Only labels 31, 32, and 33 are shown; the remaining static, dynamic, and combined static / dynamic zones are not labeled. For example, the PCB includes a 6-layer board. The static zone, projected onto the 6th layer of the PCB, has no other signals. The solid-lined area is the static zone 31, where static signals may include BUS+ and BUS- signals, which are directly connected to the external battery. The dashed-lined area is the dynamic zone 32, where dynamic signals may include INVA, INVB, and INVC signals before the inverter inductor. The dotted-dash lined area is the combined static / dynamic zone 33, which is the area where static and dynamic signals cannot be separated. The signals in the combined static / dynamic zone are mainly various signals connected to the switching unit.

[0048] The static zone 31, projected onto the multilayer board in the first circuit board along a third direction, includes static signal lines that generate static signals; the dynamic zone 32, projected onto the multilayer board in the first circuit board along a third direction, includes dynamic signal lines that generate dynamic signals; the dynamic-static combination zone 33, projected onto the multilayer board in the first circuit board along a third direction, includes dynamic signal lines that generate dynamic signals and static signal lines that generate static signals; in this embodiment, the third direction is perpendicular to the aforementioned first and second directions, that is, the third direction is perpendicular to the board surface direction of the first circuit board.

[0049] Among them, static signal refers to a signal whose voltage change rate is close to 0, and dynamic signal refers to a signal whose voltage change rate is much greater than 0.

[0050] It should be noted that a static signal refers to a signal with a constant or nearly constant voltage, while a dynamic signal refers to a signal with a large voltage change. There is no specific limit to the exact value of the voltage change rate for static and dynamic signals, but the voltage change rate of a dynamic signal is greater than that of a static signal.

[0051] In some embodiments, in the static-dynamic bonding area 33, the multilayer board in the first circuit board includes a static layer, a dynamic layer and a shielding layer.

[0052] The static layer includes signal lines that transmit static signals, and the dynamic layer includes signal lines that transmit dynamic signals.

[0053] The shielding layer is located between the static layer and the dynamic layer.

[0054] For example, the first circuit board includes a 6-layer board, which is divided into a top 3-layer board and a bottom 2-layer board in the dynamic-static junction area. The top 3 layers are dynamic layers that transmit dynamic signals; the bottom 2 layers are static layers that transmit static signals such as BUS+ and BUS-; the middle layer is a shielding layer, separated by an internal signal N-layer. Specifically, the first layer (Toplayer) can be a dynamic layer and a driver layer such as INVA, INVB, and INVC; the second layer (Midlayer1) can be a dynamic layer such as INVA, INVB, and INVC; the third layer (Midlayer2) can be a dynamic layer such as INVA, INVB, and INVC; the fourth layer (Midlayer3) can be an internal virtual N-layer; the fifth layer (Midlayer4) can be the main BUS- layer; and the sixth layer (Bottom layer) can be the main BUS+ layer.

[0055] It should be noted that there is no specific limit to the number of multilayer boards included in the first circuit board, or the specific number of static layers and dynamic layers therein, but multiple static layers and multiple dynamic layers are arranged adjacent to each other.

[0056] It should also be noted that the dynamic layer, shielding layer, and static layer can be arranged on the first circuit board from top to bottom along a third direction, or from bottom to top along a third direction. The specific choice can be made according to the actual situation.

[0057] Furthermore, in some embodiments, when the projection of the signal line transmitting a static signal onto the multilayer board in the first circuit board along a third direction does not overlap with the projection of the signal line transmitting a dynamic signal onto the multilayer board in the first circuit board along a third direction, the multilayer board in the first circuit board includes a static layer and a dynamic layer.

[0058] When the projection of the signal line transmitting static signals onto the multilayer board in the first circuit board along a third direction overlaps with the projection of the signal line transmitting dynamic signals onto the multilayer board in the first circuit board along a third direction, the multilayer board in the first circuit board includes a static layer, a dynamic layer, and a shielding layer, and the shielding layer is distributed between the static layer and the dynamic layer.

[0059] In other words, in the quiet zone and the dynamic zone, the first circuit board is also a multi-layer board, but since they transmit the same signal respectively, no shielding layer is needed in the middle; while in the dynamic-static combined zone, since both static and dynamic signals need to be transmitted, a shielding layer is needed in the middle to achieve separation of static and dynamic signals.

[0060] This disclosure provides a dual BuckBoost converter, which, through reasonable board layout, limits the mid- and high-frequency current loops to a small area within the power amplifier board; and utilizes PCB stack-up to shield the mid- and high-frequency current loops on the board; and performs dynamic and static signal partitioning (i.e., static zone, dynamic zone, and dynamic-static combination zone) and layering (i.e., static layer, dynamic layer, and shielding layer) on the board; thereby optimizing the layout of the conversion circuit and thus optimizing electromagnetic radiation.

[0061] The above description is merely a preferred embodiment of this disclosure and is not intended to limit the scope of protection of this disclosure.

[0062] It should be noted that, in this disclosure, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0063] The sequence numbers of the embodiments disclosed above are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0064] The methods disclosed in the several method embodiments provided in this disclosure can be arbitrarily combined without conflict to obtain new method embodiments.

[0065] The features disclosed in the several product embodiments provided in this disclosure can be combined arbitrarily without conflict to obtain new product embodiments.

[0066] The features disclosed in the several method or device embodiments provided in this disclosure can be arbitrarily combined without conflict to obtain new method or device embodiments.

[0067] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A dual BuckBoost converter, characterized in that... It includes several circuit boards and a three-phase conversion unit. The first DC side of each phase conversion unit is connected to a DC source, and its second DC side is connected to a three-phase DC source respectively. The conversion unit includes a first DC branch, a switch bridge arm, and a second DC branch; The first DC branch connected to the DC source includes a first filter capacitor, a second filter capacitor, a first DC inductor, and a second DC inductor. The first and second filter capacitors are connected in series across the two ends of the DC source, and the first and second DC inductors are respectively connected across the two ends of the DC source. The switch bridge arm includes four interconnected first switch units, second switch units, third switch units, and fourth switch units. The second DC branch includes a first bus capacitor and a second bus capacitor connected in series, with their midpoint connected to the midpoint of the second and third switch units. The other ends of the first and second bus capacitors are respectively connected to one end of the first and fourth switch units. 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. Each of the aforementioned conversion units generates commutation current, ripple current, and load current during the conversion process. Throughout the entire conversion process of the conversion unit, each of the first bus capacitor, second bus capacitor, first switch unit, second switch unit, third switch unit, and fourth switch unit is adapted to carry the commutation current, and each device adapted to carry the commutation current is configured to be located on the same first circuit board.

2. The conversion device according to claim 1, characterized in that: Each of the first filter capacitor, second filter capacitor, first DC inductor, second DC inductor, first switch unit, second switch unit, third switch unit, fourth switch unit, first bus capacitor, second bus capacitor, first DC inductor, and second DC inductor is adapted to carry the ripple current, and each device adapted to carry the ripple current is configured to be located on the same first circuit board.

3. The conversion device according to claim 1, characterized in that: Each of the first filter capacitor, second filter capacitor, first DC inductor, second DC inductor, first switch unit, second switch unit, third switch unit, fourth switch unit, first bus capacitor, second bus capacitor, first DC inductor, and second DC inductor is adapted to carry the ripple current, wherein the first filter capacitor, second filter capacitor, first DC inductor, and second DC inductor are configured to be located on the same second circuit board.

4. The conversion device according to claim 3, characterized in that... The second circuit board also includes a current sampling element, and the first filter capacitor, the second filter capacitor and the current sampling element are distributed sequentially on the same second circuit board.

5. The conversion device according to claim 2, characterized in that: The area through which the commutation current flows is defined as the first shielding area, and a first shielding layer is provided on the circuit board of the first shielding area; the area through which the ripple current flows is defined as the second shielding area, and a second shielding layer is provided on the circuit board of the second shielding area.

6. The conversion device according to claim 5, characterized in that: The first shielding layer and the second shielding layer are copper-clad layers, and the copper-clad thickness of the first shielding layer is greater than that of the second shielding layer; a third shielding layer is provided in the overlapping area of ​​the first shielding area and the second shielding area, the third shielding layer is a copper-clad layer, and the copper-clad thickness of the third shielding layer is greater than that of the first shielding layer and the second shielding layer.

7. The conversion device according to claim 2, characterized in that... The first circuit board includes a static area, a dynamic area, and a dynamic-static combination area, and the first circuit board includes a multilayer board; The projection of the static zone onto the multilayer board in the first circuit board along a third direction includes only static signals; the projection of the dynamic zone onto the multilayer board in the first circuit board along the third direction includes only dynamic signals; the projection of the combined static and dynamic zone onto the multilayer board in the first circuit board along a third direction includes both static and dynamic signals. Wherein, the static signal refers to a signal with a voltage change rate close to 0, and the dynamic signal refers to a signal with a voltage change rate much greater than 0; the third direction is the direction perpendicular to the surface of the first circuit board.

8. The conversion device according to claim 7, characterized in that: In the dynamic-static combination area, the multilayer board in the first circuit board is divided into a static layer, a dynamic layer and a shielding layer; The signal lines that transmit the static signals are arranged in the static layer; as well as, The signal lines that transmit the dynamic signals are arranged in the dynamic layer; as well as, The shielding layer is arranged between the static layer and the dynamic layer.

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