A modular combined DC / DC circuit system

Abstract

The present application discloses a modular combined DC / DC circuit system, which is used to match a DAB circuit topology with high voltage on the high voltage side and high current on the low voltage side; it includes at least one module M, each module M includes a submodule M HV , energy storage circuit and submodule M LV ; Energy storage circuit quilt module M HV and submodule M LV Shared, multiple modules M corresponding to multiple sub-modules M HV Connected in series on the high-voltage side of the system for voltage division, multiple modules M corresponding to multiple sub-modules M LV Connect in parallel on the low-voltage side of the system for current shunting. Beneficial effects of this application: Compared with traditional methods, this application can effectively reduce device stress under high-voltage input, low-voltage, and high-current output, so it can be applied to scenarios with large input and output voltage differences to achieve wide voltage gain. The overall circuit topology control is simple, low-cost, and the modular design facilitates subsequent expansion.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a modular combined DC / DC circuit system. Background Art

[0002] In the renewable energy power generation system, in order to meet the requirements of wide voltage range, the existing technology mainly adopts a two-stage DC converter topology. The two-stage structure topology is composed of a constant gain resonant converter and a Buck / Boost converter in series. The resonant converter realizes electrical isolation, and the Buck / Boost converter realizes voltage regulation. Although this method can achieve smooth switching of power direction and wide voltage gain, the overall conversion efficiency is low and the requirements for device stress are high. Based on this, it is urgent to improve the existing converter topology. Utility Model Content

[0003] One of the objectives of the present application is to provide a modular combined DC / DC circuit system that can solve at least one of the defects in the above-mentioned background technology.

[0004] In order to achieve at least one of the above purposes, the technical solution adopted by the present application is: a modular combined DC / DC circuit system for matching a DAB circuit topology with high voltage on the high voltage side and high current on the low voltage side; comprising at least one module M, each of which comprises a submodule M HV , energy storage circuit and submodule M LV The energy storage circuit is the submodule M HV and the submodule M LV Shared, multiple sub-modules M corresponding to multiple modules M HV The high-voltage side of the system is connected in series for voltage division, and the multiple sub-modules M corresponding to the multiple modules M LV Connect in parallel on the low pressure side of the system for flow splitting.

[0005] Preferably, the module M also includes the submodule M HV and the submodule M LV The energy storage circuit uses an energy storage inductor and is connected in series to the submodule M HV and the submodule M LV The positive busbar between.

[0006] Preferably, the submodule M LV Comprising multiple subunits M LV_ ; A plurality of said subunits M LV_ Connect in parallel on the low voltage side and in series on the high voltage side.

[0007] Preferably, the number of the modules M and the submodules M LVThe subunit M comprises LV_ The number of is multiple.

[0008] Preferably, the submodule M HV and the subunit M LV_ Both use bidirectional conduction circuits to make the high-voltage side DC V HV and low voltage side DC V LV Energy can be transferred bidirectionally.

[0009] Preferably, the submodule M HV Using a bidirectional conduction circuit, the subunit M LV_ A unidirectional conduction circuit is used to allow energy to flow from the high-voltage side DC V HV DC to low voltage side V LV One-way transmission.

[0010] Preferably, the submodule M HV Using a unidirectional conduction circuit, the subunit M LV_ A bidirectional conduction circuit is used to allow energy to flow from the low-voltage DC side to the LV DC to high voltage side V HV One-way transmission.

[0011] Preferably, the submodule M HV and the subunit M LV_ All adopt full-bridge topology.

[0012] Preferably, the semiconductor device of the bidirectional conductive loop is a switch tube.

[0013] Preferably, the semiconductor device of the unidirectional conducting loop is a diode.

[0014] Compared with the prior art, the beneficial effects of this application are:

[0015] Compared with the traditional method, this application can effectively reduce the device stress under high voltage input, low voltage and high current output, so it can be applied to the scene with large input and output voltage difference to achieve wide voltage gain. The overall circuit topology control is simple, low cost, and the modular design facilitates subsequent expansion. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the overall circuit topology of this application.

[0017] Figure 2 This is a schematic diagram of the bidirectional topology based on the DAB converter of this application.

[0018] Figure 3 For this application, submodule M HV Schematic diagram of the topology using a bidirectional conduction loop.

[0019] Figure 4 For this application, submodule M LV Schematic diagram of the topology using a bidirectional conduction loop.

[0020] Figure 5 In this application Figure 2 Workflow diagram for the topology shown.

[0021] Figure 6 This is a schematic diagram of a unidirectional topology from high voltage to low voltage based on a DAB converter in this application.

[0022] Figure 7 For this application, submodule M LV Schematic diagram of the topology using a unidirectional conduction loop.

[0023] Figure 8 This is a schematic diagram of a unidirectional topology from low voltage to high voltage based on a DAB converter in this application.

[0024] Fig. 9 For this application, submodule M HV Schematic diagram of the topology using a unidirectional conduction loop.

[0025] Fig.10 For this application Figure 6 Workflow diagram for the topology shown.

[0026] Fig.11 This is a schematic diagram of the bidirectional topology based on the LLC converter of this application.

[0027] Fig.12 This is a schematic diagram of a high-voltage to low-voltage unidirectional topology based on an LLC converter in this application.

[0028] Fig.13 This is a schematic diagram of a unidirectional topology from low voltage to high voltage based on an LLC converter in this application.

[0029] Fig.14 For this application Fig.12 Workflow diagram for the topology shown. DETAILED DESCRIPTION

[0030] Below, the present application is further described in conjunction with specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0031] In the description of the present application, it should be noted that directional words, such as the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions and positional relationships are based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of narrating the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and cannot be understood as limiting the specific scope of protection of the present application.

[0032] It should be noted that the terms "first", "second", etc. in the description and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0033] The terms "including" and "having" and any variations thereof in the specification and claims of this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0034] One of the preferred embodiments of the present application is as follows: Figure 1 As shown, a modular combined DC / DC circuit system can be applied to scenarios where the voltage difference between the two sides of the DC / DC is large, and mainly includes at least one module M; the structures of multiple modules M are exactly the same, and these modules M are connected in parallel on the low-voltage side of the system and in series on the high-voltage side, thereby forming a circuit topology with a wider voltage gain, thereby achieving large voltage difference matching between the high-voltage side and the low-voltage side of the system.

[0035] Specifically, module M includes submodules M HV and submodule M LV ; Multiple modules M corresponding to multiple sub-modules M HV Connect in series on the high-voltage side of the system, multiple modules M corresponding to multiple sub-modules M LV Connect in parallel on the low voltage side of the system. LV For low voltage side DC V LV and high frequency AC signal v ac The mutual transformation of submodule M HV For high frequency AC signal v ac and high voltage side DC V HV mutual transformation.

[0036] It should be known that the entire system is composed of multiple sub-modules M HVand multiple submodules M LV To disperse the device stress, it can effectively reduce the device stress under high voltage input, low voltage and high current output, so it can be applied to the scene with large input and output voltage difference to achieve wide voltage gain. And the overall circuit topology control of the system is simple and low cost; at the same time, the modular design of the system can facilitate subsequent expansion. That is, when the voltage gain of the system needs to be increased, only the corresponding number of modules M need to be added, otherwise the corresponding number of modules M need to be deleted.

[0037] For ease of understanding, multiple modules M can be marked as M1, M2, ..., M N , N ≥ 1; then any module M i The corresponding submodule is M HVi and submodule M LVi ; The value of i is {1, 2, ..., N}.

[0038] In this embodiment, Figure 1 As shown, submodule M LV Each includes at least one subunit M LV_ ; Multiple subunits M LV_ The submodule LV can be connected in parallel on the low voltage side and in series on the high voltage side. LV_ If the number of submodules is n, then any submodule M LVi The corresponding arbitrary subunit M LV_ Marked as M LVi_j , the value of j is {1, 2, ..., n}.

[0039] It can be understood that when the values ​​of N and n are both 1, the system only includes module M1, and module M1 only includes submodule M HV1 and subunit M LV1_1 ; then through subunit M LV1_1 Its own transformer topology can be applied to scenarios with large input and output voltage differences.

[0040] When the value of N is 1 and the value of n is greater than 1, the system only includes module M1, and module M1 includes submodules M HV1 , subunit M LV1_1 , subunit M LV1_2 , ..., subunit M LV1_n . Then through the submodule M LV1 The corresponding multiple subunits M LV1_j It can effectively reduce device stress under high voltage input, low voltage and high current output, thereby achieving a wide voltage gain in scenarios with a large input and output voltage difference.

[0041] When the value of N is greater than 1 and the value of n is 1, the system includes modules M1, M2, ..., MN ; Any module M i Include only submodule M HVi and subunit M LVi_1 . Then through multiple modules M corresponding to multiple sub-modules M HV and submodule M LV It can effectively reduce device stress under high voltage input, low voltage and high current output, thereby achieving a wide voltage gain in scenarios with a large input and output voltage difference.

[0042] When the values ​​of N and n are both greater than 1, the system includes modules M1, M2, ..., M N ; Any module M i Include submodule M HVi , subunit M LVi_1 , subunit M LVi_2 , ..., subunit M LVi_n . Then through each module M, the submodule M LV The corresponding multiple subunits M LVi_j It can further disperse the device stress under high voltage input, low voltage and high current output, so as to further improve the wide voltage gain in the scenario with large input and output voltage difference.

[0043] It should be known that the values ​​of N and n in this embodiment can be selected according to the actual needs of those skilled in the art. In order to ensure that the system can achieve a good wide voltage gain, the values ​​of N and n in this embodiment are preferably not all 1, that is, when N=1, n>1; when N is greater than 1, n can be 1 or greater than 1. In order to facilitate the description of the subsequent content, it is further preferred that the values ​​of N and n are both greater than 1 for illustration.

[0044] It should also be known that all submodules of this embodiment can realize bidirectional energy transfer, so that the entire system can realize high-voltage side DC V HV and low voltage side DC V LV Of course, all submodules in this embodiment can also realize unidirectional energy transfer, so that the entire system can realize high-voltage side DC V HV DC to low voltage side V LV One-way transfer of energy, or realization of low voltage side DC V LV DC to high voltage side V HV The energy is transferred in one direction. Moreover, this embodiment can be used as a basic architecture for obtaining a wider voltage gain in scenarios with large input and output voltage differences. For scenarios with specific requirements or detailed requirements, the architecture can be subdivided based on this embodiment. For ease of understanding, two specific embodiments will be described in detail below.

[0045] Embodiment 1:

[0046] For DAB (active bridge) converters, high voltage on the high voltage side and high current on the low voltage side. Figure 2 , Figure 6 and Figure 8 As shown, module M also includes quilt module M HV and submodule M LV A common energy storage circuit. Thus, the DAB converter performs series voltage division on the high voltage side and parallel current division on the low voltage side. The energy storage circuits corresponding to the N modules M are energy storage circuit #1, energy storage circuit #2, ..., energy storage circuit #N.

[0047] It should be known that there are many specific structures of energy storage circuits that can be applied to DAB converters. For ease of understanding, one commonly used structure will be used for description. Figure 2 , Figure 6 and Figure 8 As shown, the energy storage circuit uses an energy storage inductor, which is connected in series to the submodule M HV and submodule M LV Any module M i The corresponding energy storage inductor is marked as energy storage inductor L i .

[0048] Specifically, Figure 2 , Figure 6 and Figure 8 Submodule M HV1 、Submodule M HV2 , ..., submodule M HVN Connect in series on the high voltage side of the system. LV1 、Submodule M LV2 , ..., submodule M LVN Connect in parallel on the low voltage side of the system. HV1 and submodule M LV1 The positive busbar between them is connected in series with an energy storage inductor L1, and the submodule M HV2 and submodule M LV2 The positive busbar between the two is connected in series with an energy storage inductor L2, and so on. HVN and submodule M LVN The positive busbar between the N . Any submodule M LVi The corresponding subunit M LVi_1 , subunit M LVi_2 , ..., subunit M LVi_n The low-voltage side of the system is connected in parallel, and the high-voltage side of the system is connected in series. HV and subunit M LVi_jBoth can realize bidirectional energy transfer, so the whole system can realize high voltage side DC V HV and low voltage DC side V LV Two-way transmission.

[0049] It is understandable that during the operation of the DAB converter, there are scenarios where energy needs to be transferred bidirectionally or unidirectionally. For ease of understanding, different energy transfer scenarios will be described in detail below through specific examples.

[0050] Example 1: Figure 2 As shown, submodule M HV and subunit M LVi_j Both use bidirectional conduction circuits to make the high-voltage side DC V HV and low voltage side DC V LV Energy can be transferred bidirectionally.

[0051] It should be noted that in order to ensure that the submodule M HV and subunit M LVi_j Both can realize bidirectional energy transfer. The semiconductor device of the bidirectional conduction loop needs to have the function of bidirectional conduction. Common semiconductor devices with bidirectional conduction function are switch tubes and bidirectional thyristors, etc.; they can be selected according to the actual needs of technicians in this field. The specific structure and working principle of the switch tube and bidirectional thyristor are well known to technicians in this field, so they will not be elaborated in detail here; common switch tubes include power switch tubes, switch triodes, MOS tubes and IGBT tubes, etc. For the convenience of understanding, the subsequent content will take the switch tube as an example to illustrate the semiconductor device of the bidirectional conduction loop.

[0052] It can be understood that there are many specific structures of the bidirectional conductive loop capable of bidirectional energy transfer, such as half-bridge and full-bridge topologies; the bidirectional conductive loop in this example preferably adopts a full-bridge topology, and the specific circuit connection structure is well known to those skilled in the art. For ease of understanding, the following will be described with reference to any submodule M. HVi and subunit M LVi_j Take this as an example for a brief description.

[0053] Specifically, Figure 3 As shown, it is an arbitrary submodule M HVi The corresponding full-bridge topology bidirectional conduction loop includes the switch tube S MHi_1 , S MHi_2 , S MHi_3 and S MHi_4 . Switching tube S MHi_1 and S MHi_2 The first branch is formed in series, and the switch tube S MHi_3 and S MHi_4The first and second branches are connected in series to form a second branch, the first branch and the second branch are connected in parallel to the first busbar connected to the high voltage side, and the midpoint of the first branch and the second branch is used as the connection point of the second busbar connected to the energy storage circuit #i. The first busbar can be used as input or output; the corresponding second busbar can be used as output or input.

[0054] like Figure 4 As shown, for any subunit M LVi_j The corresponding full-bridge topology bidirectional conduction loop includes the switch tube S MLi_5 , S MLi_6 , S MLi_7 , S MLi_8 . Switching tube S MLi_5 and S MLi_6 The third branch is formed in series, and the switch tube S MLi_7 and S MLi_8 The third and fourth branches are connected in series to form a fourth branch, and the third and fourth branches are connected in parallel to the third busbar connected to the low-voltage side. The midpoint of the third and fourth branches is used as the connection point of the fourth busbar connected to the energy storage circuit #i. The third busbar can be used as input or output; the corresponding fourth busbar can be used as output or input. Since there is a voltage difference between the input and output of module M, a transformer needs to be set in module M; generally speaking, the transformer is set on the fourth busbar.

[0055] In this embodiment, for ease of understanding, the specific control process of Example 1 will be described in detail. Taking module M1 as an example, the switch tube S MH1_1 The driving signal D1 is used as the reference, and the switch tube S MH1_3 With switch tube S MH1_1 The phase shift angle is the phase shift angle D1*P in the front axle I , switch tube S ML1_1 With switch tube S MH1_1 The phase shift angle is the external phase shift angle D2*PI, and the switch tube S ML1_3 With switch tube S MH1_1 The phase shift angle is D3*PI in the rear axle. MH1_2 , S MH1_4 , S ML1_2 , S ML1_4 The conduction delay of the tubes in these four positions can be expressed by these three phase shift angles.

[0056] The specific control process is as follows: Figure 5 As shown, the control loop generates a modulation signal, and four modulation signals S1, S3, S5 and S7 are obtained through modulation. The modulation signals S2, S4, S6 and S8 are obtained by inverting and delaying the modulation signals S1, S3, S5 and S7. MH1_1 , SMH2_1 ,……,S MHN_1 , the modulation signal S2 corresponds to the switch tube S MH1_2 , S MH2_2 ,……,S MHN_2 , the modulation signal S3 corresponds to the switch tube S MH1_3 , S MH2_3 ,……,S MHN_3 , the modulation signal S4 corresponds to the switch tube S MH1_4 , S MH2_4 ,……,S MHN_4 , the modulation signal S5 corresponds to S ML1_1 , S ML2_1 ,……,S MLN_1 , the modulation signal S6 corresponds to the switch tube S ML1_2 , S ML2_2 ,……,S MLN_2 , the modulation signal S7 corresponds to the switch tube S ML1_3 , S ML2_3 ,……,S MLN_3 , the modulation signal S8 corresponds to the switch tube S ML1_4 , S ML2_4 ,…,S MLN_4 .

[0057] It should be noted that each module M1, M2, ..., M N The control is exactly the same, the module M on the high voltage side HV1 、M HV2 ……、M HVN The driving signals of the corresponding bidirectional conduction loops are the same, and the driving signals of the switches at the same position are consistent. This design makes the control of the entire circuit simple and the cost is the lowest. In order to prevent short circuits, the upper and lower switches of the same bridge arm, that is, the same branch, cannot be turned on at the same time, and the DAB driving signal uses a 50% duty cycle.

[0058] Example 2: Figure 6 As shown, submodule M HV Using a two-way conduction circuit, subunit M LVi_j A unidirectional conduction circuit is used to allow energy to flow from the high-voltage side DC V HV DC to low voltage side V LV One-way transmission.

[0059] It should be noted that the subunit M LVi_j The energy is transferred in one direction through the unidirectional conduction loop. HV Energy is transferred bidirectionally through a bidirectional conduction loop; thus, through the submodule M HV and subunit M LVi_j The energy is realized by the high voltage side DC V HV DC to low voltage side VLV One-way transmission is performed. Of course, submodule M HV It is also possible to use the subunit M L Vi_j The unidirectional conducting circuit uses a unidirectional circuit with the same conducting direction to realize the unidirectional transfer of energy.

[0060] In order to ensure that the subunit M LVi_j To achieve one-way energy transfer, it is necessary to ensure that the subunit M LVi_j It can be stably cut off in the non-conduction direction. Common semiconductor devices with unidirectional conduction function include diodes and unidirectional thyristors, etc.; the specific selection is made according to the actual needs of technicians in this field. The specific structure and working principle of diodes and unidirectional thyristors are well known to technicians in this field, so they will not be elaborated in detail here. In order to facilitate the description of subsequent content, the semiconductor device of the unidirectional conduction circuit will be explained by taking diodes as an example.

[0061] It is understandable that the submodule M HV The specific structure of the bidirectional conductive loop used can refer to the above-mentioned example 1. LVi_j There are many specific structures of the unidirectional conduction loop, such as half-bridge and full-bridge topology structures. The unidirectional conduction loop in this example preferably adopts a full-bridge topology structure. The specific circuit connection structure is well known to those skilled in the art. For ease of understanding, the following will be described with an arbitrary subunit M. LVi_j Take this as an example for a brief description.

[0062] Specifically, Figure 7 As shown, for any subunit M LVi_j The corresponding full-bridge topology unidirectional conduction loop includes a diode D MLi_5 , D MLi_6 , D MLi_7 , D MLi_8 . Diode D MLi_5 and D MLi_6 The diode D MLi_7 and D MLi_8 The third and fourth branches are connected in series to form a fourth branch, the third and fourth branches are connected in parallel to the third busbar connected to the low voltage side, and the midpoint of the third and fourth branches is used as the connection point of the fourth busbar connected to the energy storage circuit #i. The third busbar can be used as input or output; the corresponding fourth busbar can be used as output or input.

[0063] Example 3: Figure 8 As shown, submodule M HV Using a unidirectional conduction circuit, subunit M LVi_j A bidirectional conduction circuit is used to allow energy to flow from the low voltage side DC V LV DC to high voltage side VHV One-way transmission.

[0064] It should be noted that the submodule M HV Through the unidirectional conduction loop, the energy is transferred in one direction. LVi_j Energy is transferred bidirectionally through a bidirectional conduction loop; thus, through the submodule M HV and subunit M LVi_j The energy is realized by the low voltage side DC V LV DC to high voltage side V HV One-way transmission is carried out. Of course, subunit M LVi_j It can also be used with submodule M HV The unidirectional conducting circuit uses a unidirectional circuit with the same conducting direction to realize the unidirectional transfer of energy.

[0065] In order to ensure that the submodule M HV To achieve one-way energy transfer, it is necessary to ensure that the submodule M HV It can be stably cut off in the non-conduction direction. Common semiconductor devices with unidirectional conduction function include diodes and unidirectional thyristors, etc.; the specific selection is made according to the actual needs of technicians in this field. The specific structure and working principle of diodes and unidirectional thyristors are well known to technicians in this field, so they will not be elaborated in detail here. In order to facilitate the description of subsequent content, the semiconductor device of the unidirectional conduction circuit will be explained by taking diodes as an example.

[0066] It is understandable that the subunit M LVi_j The specific structure of the bidirectional conductive loop used can refer to the above-mentioned example 1. Submodule M HV There are many specific structures of the unidirectional conduction loop, such as half-bridge and full-bridge topology structures; the unidirectional conduction loop in this example preferably adopts a full-bridge topology structure. The specific circuit connection structure is well known to those skilled in the art. For ease of understanding, the following will be described with an arbitrary submodule M HVi Take this as an example for a brief description.

[0067] Specifically, Fig. 9 As shown, it is an arbitrary submodule M HVi The corresponding full-bridge topology unidirectional conduction loop includes a diode D MHi_1 , D MHi_2 , D MHi_3 and D MHi_4 . Diode D MHi_1 and D MHi_2 The diodes D MHi_3 and D MHi_4The first and second branches are connected in series to form a second branch, the first branch and the second branch are connected in parallel to the first busbar connected to the high voltage side, and the midpoint of the first branch and the second branch is used as the connection point of the second busbar connected to the energy storage circuit #i. The first busbar can be used as input or output; the corresponding second busbar can be used as output or input.

[0068] In this embodiment, the control process of Example 2 is similar to that of Example 3. For ease of understanding, Example 2 will be used as an example for detailed description. Figure 3 , Figure 6 , Figure 7 and Fig.10 As shown, taking module M1 as an example, in submodule M HV1 In the bidirectional conduction circuit, the switch tube S MH1_1 The drain and switch S MH1_3 The drain of the switch tube S is connected to the positive electrode of the high voltage side of the system; MH 1_2 The source and switch tube S MH1_4 The source of the switch tube S is connected to the negative electrode of the high voltage side of the system; MH1_1 The source and switch tube S MH1_2 The drain of the switch tube S is connected to form the first switch bridge arm, that is, the first branch; MH1_3 The source and switch tube S MH1_4 The drain of the switch tube S is connected to form a second switch bridge arm, that is, a second branch; MH1_1 The source or switch S MH1_2 The drain of is connected to the positive electrode of the energy storage inductor L1, S MH1_3 The source or switch S MH1_4 The drain and submodule M LV1 The corresponding primary negative pole of the nth transformer is connected.

[0069] In any subunit M LV1_j In the unidirectional conduction circuit, the diode D ML1_5 The positive electrode of the diode D ML1_6 The cathode of diode D is connected to form the third switch bridge arm, i.e. the third branch; ML1_7 The positive electrode of the diode D ML1_8 The cathode of diode D is connected to form the fourth switch bridge arm, i.e. the fourth branch; ML1_5 The positive electrode of the jth transformer is connected to the positive electrode of the secondary side, and the diode D ML1_7 The negative electrode of the diode D is connected to the negative electrode of the secondary side of the jth transformer. ML1_5 and diode D ML1_7 The positive pole of the diode D is connected to the positive pole of the low voltage side of the system; ML1_6 and diode D ML1_8 The negative pole is connected to the negative pole on the low voltage side of the system.

[0070] It should be noted that each module M1, M2, ..., M N The structure and control are exactly the same, the submodule M on the high-voltage side HV1 Bidirectional conduction circuit, submodule M HV2 The bidirectional conducting circuit, ..., submodule M HVN The driving signals of the bidirectional conduction circuits are the same, and the driving signals of the switch tubes in the same position are consistent. This design will make the control of the entire circuit simple and the cost lowest.

[0071] The specific control process is as follows: the phase shift angle of the modulation signal generated by the control loop If the drive signal S1 is used as a reference, the phase shift angle between the drive signal S3 and the drive signal S1 can be used as the phase shift angle within the front axle. Based on the phase shift angle After modulation, the modulation signals S1, S2, S3 and S4 corresponding to the four switching tubes can be obtained respectively. In the current unidirectional architecture based on the DAB converter energy from high voltage to low voltage, the four modulation signals S1, S2, S3 and S4 correspond to the control of the switching tubes at four positions in each bidirectional conduction loop. That is, the modulation signal S1 corresponds to the switching tube S MH1_1 , S MH2_1 ,……,S MHN_1 , the modulation signal S2 corresponds to the switch tube S MH1_2 , S MH2_2 ,……,S MHN_2 , the modulation signal S3 corresponds to the switch tube S MH1_3 , S MH2_3 ,……,S MHN_3 , the modulation signal S4 corresponds to the switch tube S MH1_4 , S MH2_4 ,……,S MHN_4 .

[0072] Embodiment 2:

[0073] Compared with the first embodiment, the difference of this embodiment is that: Figures 11 to 13 As shown, the energy storage circuit in the embodiment is replaced by a resonant cavity. Thus, the LLC converter performs series voltage division on the high voltage side and parallel current division on the low voltage side. The resonant cavities corresponding to the N modules M are resonant cavity #1, resonant cavity #2, ..., resonant cavity #N.

[0074] Specifically, there are many specific structures of the resonant cavity that can be applied to the LLC converter. For ease of understanding, one commonly used structure will be used for description. Figures 11 to 13 As shown, the resonant cavity adopts LLC circuit topology, including inductor L m 、Inductance L r and capacitor Cr ; Inductance L r and capacitor C r Installed in series on submodule M HV and submodule M LV The positive busbar between m Connected in parallel to submodule M LV The corresponding subunit M LVi_j on the high-voltage side so that the inductor L m 、Inductance L r and capacitor C r Connect in series.

[0075] It should be known that each resonant cavity includes an inductor L m The number of each submodule M LV The corresponding subunit M LVi_j The number of is equal. Then the inductance L included in any resonant cavity #i m Can be marked as L mi_1 , L mi_2 ,……,L mi_n ; In any resonant cavity #i, the inductance L r and capacitor C r And the inductor L mi_1 , L mi_2 ,……,L mi_n Connected in series.

[0076] It should also be known that during the operation of the LLC converter, there are also scenarios where energy needs to be transferred bidirectionally or unidirectionally. Fig.11 As shown, submodule M HV and subunit M LVi_j Bidirectional conduction circuits can be used. For scenarios where one-way energy transfer is required, such as Fig.12 As shown, submodule M HV Using a two-way conduction circuit, subunit M LVi_j A unidirectional conduction circuit is used to allow energy to flow from the high-voltage side DC V HV DC to low voltage side V LV One-way transmission; or Fig.13 As shown, submodule M HV Using a unidirectional conduction circuit, subunit M LVi_j A bidirectional conduction circuit is used to allow energy to flow from the low voltage side DC V LV DC to high voltage side V HV One-way transmission is performed. For submodule M HV and subunit M LVi_j The specific circuit structure is the same as that of the above-mentioned embodiment 1, and reference may be made to the above-mentioned embodiment 1, so it will not be elaborated in detail here.

[0077] In this embodiment, the specific control process for the LLC converter application scenario will be based on the submodule M HV Using a unidirectional conduction circuit, subunit M LVi_j A bidirectional conductive circuit is used as an example for detailed description.

[0078] like Figure 3 , Figure 7 , Fig.12 and Fig.14 As shown, taking module M1 as an example, in submodule M HV1 In the bidirectional conduction circuit, the switch tube S MH1_1 The drain and switch S MH1_3 The drain of the switch tube S is connected to the positive electrode of the high voltage side of the system; MH1_2 The source and switch tube S MH1_4 The source of the switch tube S is connected to the negative electrode of the high voltage side of the system; MH1_1 The source and switch tube S MH1_2 The drain of the switch tube S is connected to form the first switch bridge arm, that is, the first branch; MH1_3 The source and switch tube S MH1_4 The drain of the switch tube S is connected to form a second switch bridge arm, that is, a second branch; MH1_1 The source or switch S MH1_2 The drain and capacitor C r1 The positive connection, S MH1_3 The source or switch S MH1_4 The drain and submodule M LV1 The corresponding primary negative pole of the nth transformer is connected. m1_1 , L m1_2 ,……,L m1_n are connected to the subunit M LV1_1 、M LV1_2 ,……,M LV1_n Between the positive and negative poles of the corresponding primary side of the transformer.

[0079] In any subunit M LV1_j In the unidirectional conduction circuit, the diode D ML1_5 The positive electrode of the diode D ML1_6 The cathode of diode D is connected to form the third switch bridge arm, i.e. the third branch; ML1_7 The positive electrode of the diode D ML1_8 The cathode of diode D is connected to form the fourth switch bridge arm, i.e. the fourth branch; ML1_5 The positive electrode of the jth transformer is connected to the positive electrode of the secondary side, and the diode D ML1_7 The negative electrode of the diode D is connected to the negative electrode of the secondary side of the jth transformer. ML1_5 and diode D ML1_7The positive pole of the diode D is connected to the positive pole of the low voltage side of the system; ML1_6 and diode D ML1_8 The negative pole is connected to the negative pole on the low voltage side of the system.

[0080] It should be noted that each module M1, M2, ..., M N The structure and control are exactly the same, the submodule M on the high-voltage side HV1 Bidirectional conduction circuit, submodule M HV2 The bidirectional conducting circuit, ..., submodule M HVN The driving signals of the bidirectional conduction circuits are the same, and the driving signals of the switch tubes in the same position are consistent. This design will make the control of the entire circuit simple and the cost lowest.

[0081] The specific control process is as follows: the phase shift angle of the modulation signal generated by the control loop If the drive signal S1 is used as a reference, the phase shift angle between the drive signal S3 and the drive signal S1 can be used as the phase shift angle within the front axle. Based on the phase shift angle After modulation, the modulation signals S1, S2, S3 and S4 corresponding to the four switching tubes can be obtained respectively. In the current unidirectional architecture based on the DAB converter energy from high voltage to low voltage, the four modulation signals S1, S2, S3 and S4 correspond to the control of the switching tubes at four positions in each bidirectional conduction loop. That is, the modulation signal S1 corresponds to the switching tube S MH1_1 , S MH2_1 ,……,S MHN_1 , the modulation signal S2 corresponds to the switch tube S MH1_2 , S MH2_2 ,……,S MHN_2 , the modulation signal S3 corresponds to the switch tube S MH1_3 , S MH2_3 ,……,S MHN_3 , the modulation signal S4 corresponds to the switch tube S MH1_4 , S MH2_4 ,……,S MHN_4 .

[0082] The control loop generates the modulation signal frequency f, and then a 50% duty cycle modulation signal is obtained based on the frequency f. After modulation, two modulation signals S and S are obtained. * In the current unidirectional architecture based on the LLC converter energy from high voltage to low voltage, the switch tubes at the four positions in each bidirectional conduction loop are S1, S2, S3 and S4 respectively; the modulation signal S controls the switch tubes S1 and S4, and the modulation signal S * Control switch tubes S2 and S3. Switch tube S1 corresponds to switch tube S MH1_1 , S MH2_1 ,……,S MHN_1, switch tube S2 corresponds to switch tube S MH1_2 , S MH2_2 ,……,S MHN_2 , switch tube S3 corresponds to switch tube S MH1_3 , S MH2_3 ,……,S MHN_3 , switch tube S4 corresponds to switch tube S MH1_4 , S MH2_4 ,……,S MHN_4 .

[0083] The above describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments, and the above embodiments and the specification only describe the principles of the present application. The present application may have various changes and improvements without departing from the spirit and scope of the present application, and these changes and improvements fall within the scope of the present application for which protection is sought. The scope of protection claimed by the present application is defined by the attached claims and their equivalents.

Claims

1. A modular combined DC / DC circuit system for matching a DAB circuit topology with high voltage on the high voltage side and high current on the low voltage side; characterized in that: It includes at least one module M, each of which includes a submodule M HV , energy storage circuit and submodule M LV The energy storage circuit is the submodule M HV and the submodule M LV Shared, multiple sub-modules M corresponding to multiple modules M HV The high-voltage side of the system is connected in series for voltage division, and the multiple sub-modules M corresponding to the multiple modules M LV Connect in parallel on the low pressure side of the system for flow splitting.

2. The modular combined DC / DC circuit system according to claim 1, characterized in that: The energy storage circuit uses an energy storage inductor; the energy storage inductor is connected in series to the submodule M HV and the submodule M LV The positive busbar between.

3. The modular combined DC / DC circuit system according to claim 1, characterized in that: The submodule M LV Comprising at least one subunit M LV_ ; A plurality of said subunits M LV_ Connect in parallel on the low voltage side and in series on the high voltage side.

4. The modular combined DC / DC circuit system according to claim 3, characterized in that: The number of modules M and the number of submodules M LV The subunit M comprises LV_ The number of is multiple.

5. The modular combined DC / DC circuit system according to claim 3, characterized in that: The submodule M HV and the subunit M LV_ Both use bidirectional conduction circuits.

6. The modular combined DC / DC circuit system according to claim 3, characterized in that: The submodule M HV Using a bidirectional conduction circuit, the subunit M LV_ A unidirectional conduction circuit is used.

7. The modular combined DC / DC circuit system according to claim 3, characterized in that: The submodule M HV Using a unidirectional conduction circuit, the subunit M LV_ A two-way conductive circuit is used.

8. The modular combined DC / DC circuit system according to any one of claims 5 to 7, characterized in that: The submodule M HV and the subunit M LV_ All adopt full-bridge topology.

9. The modular combined DC / DC circuit system according to any one of claims 5 to 7, characterized in that: The semiconductor device used in the bidirectional conductive loop is a switch tube.

10. The modular combined DC / DC circuit system according to claim 6 or 7, characterized in that: The semiconductor device used in the unidirectional conduction loop is a diode.

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