Control method of dc / dc conversion circuit and related device

Abstract

The application discloses a control method and related device of a DC / DC conversion circuit, and relates to the technical field of power conversion. The DC / DC conversion circuit is characterized in that a corresponding voltage stabilizer is connected in series with a switch tube between positive and negative transmission branches in a first BOOST circuit. When the switch tube is turned on, the voltage across the inductor in the corresponding first BOOST circuit is the difference between the input voltage of the first BOOST circuit and the voltage of the voltage stabilizer, so that the inductance current change rate can be reduced, and the inductance current ripple rate is reduced, so that the inductor can select a device with a smaller inductance value. When the switch tube is turned off, the voltage across the switch tube is the difference between the output voltage of the DC / DC conversion circuit and the voltage of the voltage stabilizer, so that the voltage across the switch tube can be reduced.

Description

Technical Field

[0001] This application relates to the field of power conversion technology, and in particular to a control method and related apparatus for a DC / DC conversion circuit. Background Technology

[0002] In a two-stage inverter system, a DC / DC converter circuit is typically placed before the subsequent DC / AC converter circuit to control the voltage of the power supply connected to the DC side of the system. As the DC-side voltage level of the system continues to increase, the voltage withstand requirements for power switching devices such as IGBTs (Insulated Gate Bipolar Transistors) or MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) in the preceding DC / DC converter circuit are also becoming increasingly stringent. Simultaneously, the ripple rate of the inductor current in the preceding DC / DC converter circuit is usually also high, requiring the selection of inductors with larger inductance values ​​or higher switching frequencies, which is detrimental to the product design of the corresponding equipment. Summary of the Invention

[0003] In view of the above problems, this application provides a control method and related apparatus for a DC / DC converter circuit to reduce the voltage across the power switching devices and the ripple rate of the inductor current in the front-end DC / DC converter circuit. The specific solution is as follows:

[0004] This application provides a DC / DC converter circuit, comprising: at least one first BOOST circuit and at least one voltage regulator; wherein...

[0005] The input terminal of the first BOOST circuit is connected to the corresponding input interface of the DC / DC converter circuit;

[0006] The output of the first BOOST circuit is connected to the output of the DC / DC converter circuit;

[0007] In the first BOOST circuit, the switching transistor between the positive and negative transmission branches is connected in series with the corresponding voltage regulator.

[0008] In one possible implementation, the number of the first BOOST circuit and the voltage regulator is greater than 1, and the first BOOST circuit and the voltage regulator are connected in a one-to-one correspondence.

[0009] Alternatively, the number of voltage regulators is greater than 1, and at least one of the first BOOST circuits is connected to at least two voltage regulators;

[0010] Alternatively, the number of the first BOOST circuits is greater than 1, and there are at least two of the first BOOST circuits connected to the same voltage regulator;

[0011] Alternatively, the number of voltage regulators is 1, the number of first BOOST circuits is greater than 1, and each first BOOST circuit is connected in series with the voltage regulator.

[0012] In one possible implementation, the voltage regulator includes: a voltage regulator chip; the output terminal of the voltage regulator chip is connected in series with a switching transistor between the positive and negative transmission branches in the corresponding first BOOST circuit;

[0013] Alternatively, the voltage regulator includes: a voltage regulator load; the input terminal of the voltage regulator load is connected in series with the switching transistor between the positive and negative transmission branches in the corresponding first BOOST circuit;

[0014] Alternatively, the voltage regulator may include: a second BOOST circuit; the input terminal of the second BOOST circuit is connected in series with the switching transistors between the corresponding positive and negative transmission branches in the first BOOST circuit.

[0015] In one possible implementation, the output of the second BOOST circuit is connected to the output of the DC / DC converter circuit;

[0016] Alternatively, the output of the second BOOST circuit can be connected to a battery or load circuit.

[0017] In one possible implementation, the second BOOST circuit is a two-level BOOST topology or a three-level BOOST topology.

[0018] In one possible implementation, the first BOOST circuit is a two-level BOOST topology or a three-level BOOST topology.

[0019] In one possible implementation, the DC / DC converter circuit further includes: at least one unidirectional conducting device;

[0020] The unidirectional conducting device is connected in series with the switching transistor between the positive and negative transmission branches in the corresponding first BOOST circuit.

[0021] The conduction direction of the unidirectional conducting device is the direction of the current flowing when the connected switch is controlled to conduct.

[0022] In one possible implementation, the positive input terminal of the first BOOST circuit is connected to the positive input terminal of the corresponding input interface of the DC / DC converter circuit, the positive output terminal of the first BOOST circuit is connected to the positive output terminal of the DC / DC converter circuit, the negative input terminal and the negative output terminal of the first BOOST circuit are connected to the negative input terminal and the negative output terminal of the DC / DC converter circuit, and the corresponding voltage regulator is connected between the switching transistor and the negative transmission branch in the positive and negative transmission branches of the first BOOST circuit.

[0023] Alternatively, the negative input terminal of the first BOOST circuit is connected to the negative input terminal of the corresponding input interface of the DC / DC converter circuit, the negative output terminal of the first BOOST circuit is connected to the negative output terminal of the DC / DC converter circuit, the positive input terminal and the positive output terminal of the first BOOST circuit are connected to the positive input terminal and the positive output terminal of the corresponding input interface of the DC / DC converter circuit, and the corresponding voltage regulator is connected between the switching transistor and the positive transmission branch in the first BOOST circuit.

[0024] A second aspect of this application provides a control method for a DC / DC converter circuit, comprising:

[0025] With a preset voltage as the target, the voltage regulator connected in series with the switching transistor in the DC / DC conversion circuit and the positive and negative transmission branch in the first BOOST circuit is controlled to operate;

[0026] Control the operation of the first BOOST circuit.

[0027] In one possible implementation, the objective of controlling the operation of the first BOOST circuit is to make the first BOOST circuit operate at the maximum power point of the power supply to which it is connected.

[0028] In one possible implementation, controlling the operation of the first BOOST circuit includes:

[0029] If the input voltage of the first BOOST circuit is greater than the voltage of the voltage regulator connected to the first BOOST circuit, then the first BOOST circuit is controlled to adjust its own input voltage.

[0030] If at least two first BOOST circuits share the same voltage regulator and the input characteristics of each first BOOST circuit meet a preset consistency condition, or if the voltage of the voltage regulator connected to the first BOOST circuit is equal to the maximum power point voltage of the power supply connected to the first BOOST circuit, then the switching transistor between the positive and negative transmission branches in the first BOOST circuit is controlled to be constantly on.

[0031] In one possible implementation, controlling the first BOOST circuit to adjust its own input voltage includes:

[0032] Control the chopping action of the switching transistor between the positive and negative transmission branches in the first BOOST circuit.

[0033] In one possible implementation, the operation of a voltage regulator connected in series with the switching transistor in the DC / DC converter circuit and the positive and negative transmission branches in the first BOOST circuit is controlled with a preset voltage as the target, including:

[0034] Using the preset voltage as the voltage control target for the voltage regulator, the voltage regulator is controlled to operate so that it bears a preset portion of the input voltage of the first BOOST circuit to which it is connected.

[0035] In one possible implementation, for at least two of the first BOOST circuits sharing the same regulated voltage source, the preset voltage is:

[0036] The minimum input voltage of all the first BOOST circuits currently connected to the voltage regulator;

[0037] Alternatively, if the power supply connected to the first BOOST circuit includes a photovoltaic module, the preset value corresponding to the current illumination conditions.

[0038] A third aspect of this application provides a controller, comprising: a processor and a memory, wherein the memory is used to store programs, instructions or code, and the processor is used to execute the programs, instructions or code in the memory to perform a control method for a DC / DC converter circuit as described in the second aspect or any implementation thereof.

[0039] A fourth aspect of this application provides a power converter, comprising: a controller and a DC / DC conversion circuit as described in the first aspect or any implementation thereof; wherein...

[0040] The DC / DC conversion circuit is controlled by the controller;

[0041] The controller is used to execute the control method for the DC / DC conversion circuit as described in the second aspect or any implementation thereof.

[0042] In one possible implementation, the power converter further includes a DC / AC conversion circuit;

[0043] The DC side of the DC / AC conversion circuit is connected to the output terminal of the DC / DC conversion circuit;

[0044] The AC side of the DC / AC conversion circuit is used to connect to the power grid and / or the load;

[0045] The DC / AC conversion circuit is controlled by the controller.

[0046] Using the above technical solution, the DC / DC converter circuit provided in this application has its first BOOST circuit input terminal connected to the corresponding input interface of the DC / DC converter circuit, and its output terminal connected to the output terminal of the DC / DC converter circuit. Furthermore, a corresponding voltage regulator is connected in series between the switching transistors of the positive and negative transmission branches in the first BOOST circuit. When the switching transistor is turned on, the voltage across the inductor in the corresponding first BOOST circuit is the difference between the input voltage of the first BOOST circuit and the voltage of the voltage regulator, which can reduce the rate of change of the inductor current, thereby reducing the ripple rate of the inductor current and allowing the selection of a device with a smaller inductance value. When the switching transistor is turned off, the voltage across it is the difference between the output voltage of the DC / DC converter circuit and the voltage of the voltage regulator, thereby reducing the voltage across the switching transistor. Attached Figure Description

[0047] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and the originals and elements are not necessarily drawn to scale.

[0048] Figure 1 A schematic diagram of a DC / DC converter circuit provided in an embodiment of this application;

[0049] Figure 2 This is a schematic diagram of another structure of the DC / DC converter circuit provided in the embodiments of this application;

[0050] Figure 3 This is a schematic diagram of another structure of the DC / DC converter circuit provided in the embodiments of this application;

[0051] Figure 4 This is a schematic diagram of another structure of the DC / DC converter circuit provided in the embodiments of this application;

[0052] Figure 5 A circuit diagram of a DC / DC converter circuit provided in an embodiment of this application;

[0053] Figure 6 A schematic diagram of a current path for a DC / DC converter circuit provided in an embodiment of this application;

[0054] Figure 7 A schematic diagram of another current path for the DC / DC converter circuit provided in the embodiments of this application;

[0055] Figure 8 A schematic diagram of another current path for the DC / DC converter circuit provided in the embodiments of this application;

[0056] Figure 9 A schematic diagram of another current path for the DC / DC converter circuit provided in the embodiments of this application;

[0057] Figure 10 A schematic diagram of another current path for the DC / DC converter circuit provided in the embodiments of this application;

[0058] Figure 11 A schematic diagram of another current path for the DC / DC converter circuit provided in the embodiments of this application;

[0059] Figure 12 Another circuit diagram of the DC / DC converter circuit provided in the embodiments of this application;

[0060] Figure 13 This is a schematic diagram of another structure of the DC / DC converter circuit provided in the embodiments of this application;

[0061] Figure 14 A flowchart of a control method for a DC / DC converter circuit provided in an embodiment of this application;

[0062] Figure 15 A schematic diagram of the structure of a controller provided in an embodiment of this application;

[0063] Figure 16 This is a schematic diagram of a power converter provided in an embodiment of this application;

[0064] Figure 17 This is another schematic diagram of the power converter provided in the embodiments of this application;

[0065] Figure 18 This is another schematic diagram of the power converter provided in the embodiments of this application;

[0066] Figure 19 This is another schematic diagram of the power converter provided in the embodiments of this application. Detailed Implementation

[0067] The embodiments of this application are described below with reference to the accompanying drawings. The terminology used in the implementation section of this application is for explaining specific embodiments only and is not intended to limit the scope of this application.

[0068] The embodiments of this application are described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Those skilled in the art will understand that with the development of technology and the emergence of new scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.

[0069] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms are interchangeable where appropriate; this is merely a way of distinguishing objects with the same attributes in the embodiments of this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of elements is not necessarily limited to those elements, but may include other elements not explicitly listed or inherent to those processes, methods, products, or apparatuses.

[0070] Taking a two-stage inverter system in the photovoltaic field as an example, in current systems with voltage levels of 1500V or higher, a three-level BOOST topology is usually used as the front-end DC / DC conversion circuit to meet high voltage requirements. Essentially, this involves sharing the voltage between two identical power switching devices and reducing the withstand voltage of the power switching devices through an intermediate charging and discharging capacitor.

[0071] For example, in string inverters, the front-end DC / DC conversion circuit typically employs multiple three-level boost converter circuits to achieve MPPT (Maximum Power Point Tracking) for each photovoltaic string, thereby increasing the inverter's power generation. Taking a common 1500V system as an example, if the three-level boost converter circuit uses a three-level flying capacitor boost topology, each circuit requires at least two power switching devices with a withstand voltage greater than 750V to achieve the boost function, and also needs a charging / discharging capacitor. Its current ripple rate is half that of a three-level symmetrical boost topology. However, if the three-level boost converter circuit uses a three-level symmetrical topology, each circuit still requires at least two power switching devices with a withstand voltage greater than 750V to achieve the boost function. Although no charging / discharging capacitor is needed, the current ripple rate is twice that of a three-level flying capacitor boost topology. A higher ripple rate requires a larger inductance value or a higher switching frequency in the three-level boost converter circuit under the same conditions, making product design more challenging. Furthermore, DC / DC converter circuits that implement MPPT functionality for multiple photovoltaic strings typically require high-voltage power switching devices.

[0072] Therefore, this application provides a DC / DC converter circuit to reduce the voltage across the power switching devices and the ripple rate of the inductor current in the preceding DC / DC converter circuit. The specific solution is as follows:

[0073] like Figure 1 As shown, the DC / DC converter circuit 10 includes: at least one ( Figure 1 (Taking one as an example) First BOOST circuit 101 and at least one ( Figure 1 (Taking one as an example for demonstration) Voltage Regulator 102; where:

[0074] The input terminal of the first BOOST circuit 101 is connected to the corresponding input interface of the DC / DC converter circuit 10. Each input interface of the DC / DC converter circuit 10 is used to connect to a corresponding power supply (as shown in the figure, Input 20). A power supply 20 can be a photovoltaic string or at least two photovoltaic strings connected in parallel, or a battery cluster or at least two battery clusters connected in parallel. Furthermore, the configuration of each power supply 20 can be the same or different, depending on the specific application environment, and all are within the scope of protection of this application. In practical applications, the number of first BOOST circuits 101 can be greater than one. Figure 2The example shown uses N first BOOST circuits (BOOST#1, BOOST#2, ..., BOOST#N) 101 as an example; at this time, the input terminal of each first BOOST circuit 101 is connected to the corresponding power supply (Input#1, Input#2, ..., Input#N) 20 through the corresponding interface of the input terminal of the DC / DC converter circuit 10.

[0075] The output terminal of the first BOOST circuit 101 is connected to the output terminal of the DC / DC converter circuit 10 (whose voltage is...). Figure 1 (as shown in the image). Figure 2 As shown, when the number of the first BOOST circuits 101 is greater than 1, the output terminals of each first BOOST circuit 101 are connected in parallel to the output terminal of the DC / DC converter circuit 10. The output terminal of the DC / DC converter circuit 10 can be connected to the DC side of the subsequent DC / AC converter circuit in the photovoltaic inverter system. In practical applications, the output terminals of each first BOOST circuit 101 can be connected to the DC side of the DC / AC converter circuit through a DC bus.

[0076] Figure 1 and Figure 2 The first BOOST circuit 101 is used as an example to demonstrate the basic BOOST topology. Figure 1 and Figure 2 As shown, the first BOOST circuit 101 includes: an inductor (such as...) Figure 1 The L shown, or, as Figure 2 The L1, L2, ..., LN shown in the diagram), and the switching transistors (such as... Figure 1 The S shown, or, as in Figure 2 The S1, S2, ..., SN shown in the figure) and diodes (such as Figure 1 The D shown, or, as in Figure 2 D1, D2, ..., DN are shown in the figure; wherein, the switching transistor is a power switching device connected between the positive and negative transmission branches of the first BOOST circuit 101, the inductor is disposed between the input terminal of the first BOOST circuit 101 and the switching transistor, and the diode is disposed between the switching transistor and the output terminal of the first BOOST circuit 101.

[0077] The switching transistor can be a MOSFET or an IGBT, etc., and there is no limitation here. Its second terminal can specifically be... Figure 1 or Figure 2 The emitter shown is not limited to this; other implementations in related technologies are also within the scope of protection of this application.

[0078] Furthermore, the switching transistors between the positive and negative transmission branches in the first BOOST circuit 101 are connected in series with the corresponding voltage regulator 102. For example... Figure 1 As shown, the switching transistor S and the voltage regulator 102 are connected in series between the positive and negative transmission branches of the first BOOST circuit 101; in practical applications, the series connection order of the voltage regulator 102 and the switching transistor S is not limited; for example, the voltage regulator 102 can be connected between the second terminal of the switching transistor S and the negative transmission branch (e.g., Figure 1 or Figure 2 As shown in the figure, a voltage regulator 102 (not shown) can also be connected between the first end of the switch S and the positive transmission branch; this is not limited here, and can be determined according to the specific application environment, all of which are within the protection scope of this application.

[0079] by Figure 1 Taking the structure shown as an example, the input voltage of the first BOOST circuit 101 is Vin, and the output voltage is Vout. If there is no voltage regulator 102, then: when the switch S is turned on, the voltage across the inductor L is the input voltage Vin; when the switch S is turned off, the voltage across the switch S is the output voltage Vout. And for... Figure 1 The scenario shown illustrates a situation where a voltage regulator 102 is connected in series with a switching transistor S. Assuming the operating voltage of the voltage regulator 102 is V0, then: When the switching transistor S is on, the voltage across the inductor L is Vin - V0, which effectively reduces the voltage across the inductor L as the current increases. This reduces the rate of change of the inductor current, thereby reducing the ripple rate and allowing the selection of a device with a smaller inductance value. When the switching transistor S is off, the voltage across it is Vout - V0, which also reduces the voltage that the switching transistor S needs to withstand, allowing the selection of a power switching device with a lower voltage tolerance. For Figure 2 The principle of each of the first BOOST circuits 101 shown is the same, and will not be described again.

[0080] It can be seen that by controlling the voltage V0 of the voltage regulator 102, the inductor current ripple rate and the voltage amplitude that the power switching devices need to withstand can be controlled. This embodiment does not limit the voltage V0 of the voltage regulator 102; as long as V0 > 0, the inductor current ripple rate and the voltage amplitude that the power switching devices need to withstand can be reduced. When the voltage V0 of the voltage regulator 102 is large, not only can the inductor current ripple rate be significantly reduced, but the voltage that the switching transistor S needs to withstand during the turn-off period can even be much lower than half of the system voltage level, which is beneficial for device selection.

[0081] The DC / DC converter circuit provided in this embodiment, through the above-described principle, can reduce the ripple rate of the inductor current, allowing the selection of inductors with smaller inductance values; moreover, it can reduce the voltage across the switching transistor, allowing the selection of power switching devices with lower voltage withstand levels; furthermore, the DC / DC converter circuit can be flexibly selected according to cost requirements and application scenarios.

[0082] In addition, the inductance value of the inductor and the voltage rating of the switching transistor are both relatively small, resulting in a lower cost for the DC / DC converter circuit. The more parallel circuits of the first BOOST circuit 101 in the DC / DC converter circuit, the greater the cost advantage of the DC / DC converter circuit.

[0083] In practical applications, the first BOOST circuit 101 can adopt either a common negative terminal structure or a common positive terminal structure. Under the common negative terminal structure, such as... Figure 1 or Figure 2 As shown, the input and output terminals of the first BOOST circuit 101 share a common negative terminal (its potential is...). Figure 1 and Figure 2 The Vcom shown refers to the negative input terminal and the negative output terminal of the first BOOST circuit 101, which are connected to the negative input terminal and the negative output terminal of the corresponding input terminal of the DC / DC converter circuit 10. The positive input terminal of the first BOOST circuit 101 is connected to the positive input terminal of the corresponding input terminal of the DC / DC converter circuit 10, and can be connected to the positive terminal of the corresponding power supply 20. The positive output terminal of the first BOOST circuit 101 is connected to the positive output terminal of the DC / DC converter circuit 10. In addition, the corresponding voltage regulator 102 is connected between the switching transistor and the negative transmission branch in the first BOOST circuit 101. Figure 3 Taking the first BOOST circuit 101 with a quantity of N as an example, the common positive electrode structure is illustrated, such as... Figure 3 As shown, the input and output terminals of the first BOOST circuit 101 share a common positive terminal, meaning that the positive terminals of the input and output of the first BOOST circuit 101 are connected to the positive terminals of the corresponding input interfaces and outputs of the DC / DC converter circuit 10. The negative terminal of the input of the first BOOST circuit 101 is connected to the negative terminal of the corresponding input interface of the DC / DC converter circuit 10, and can be connected to the negative terminal of the corresponding power supply 20. The negative terminal of the output of the first BOOST circuit 101 is connected to the negative terminal of the output of the DC / DC converter circuit 10. In addition, the corresponding voltage regulator 102 is connected between the switching transistor and the positive transmission branch in the first BOOST circuit 101.

[0084] For the common negative electrode structure, please refer to Figure 1 or Figure 2The negative transmission branch of the first BOOST circuit 101 contains only the corresponding wires, while the inductors and diodes inside the first BOOST circuit 101 are all located in the positive transmission branch; specifically, taking Figure 1 Taking the first BOOST circuit 101 as an example, one end of the inductor L serves as the positive input terminal of the first BOOST circuit 101, the other end of the inductor L is connected to the first terminal of the switch S and the anode of the diode D, the cathode of the diode D is connected to the positive output terminal of the first BOOST circuit 101, and the second terminal of the switch S is used to connect to the negative transmission branch of the first BOOST circuit 101. Figure 2 The internal component connections of each first BOOST circuit 101 are the same as those described above, and will not be repeated here.

[0085] For the common cathode structure, please refer to Figure 3 The positive transmission branch of the first BOOST circuit 101 contains only the corresponding wires, while the inductors and diodes inside the first BOOST circuit 101 are all located in the negative transmission branch; specifically, taking Figure 3 Taking the first BOOST circuit 101 at the bottom as an example, one end of its inductor L1 serves as the negative input terminal of the first BOOST circuit 101, and the other end of the inductor L1 is connected to the second terminal of the switch S1 and the cathode of the diode D1. The anode of the diode D1 is connected to the negative output terminal of the first BOOST circuit 101, and the first terminal of the switch S1 is used to connect to the positive transmission branch of the first BOOST circuit 101. Figure 3 The internal component connections of the other first BOOST circuits 101 are the same, and will not be described in detail here.

[0086] That is, this application does not limit the transmission branch in which the inductor and diode in the first BOOST circuit 101 are located; they can be in the positive transmission branch or in the negative transmission branch.

[0087] Furthermore, the series connection order of the voltage regulator 102 and the switching transistor in the first BOOST circuit 101 is not limited under either structure; for example, for any first BOOST circuit 101 in the common negative structure, a voltage regulator 102 can be connected between the second terminal of its switching transistor and the negative transmission branch (e.g. Figure 1 or Figure 2 As shown in the diagram, a voltage regulator 102 (not shown) can also be connected between the first terminal of its switching transistor and the positive transmission branch; for any first BOOST circuit 101 in a common positive structure, a voltage regulator 102 (not shown) can be connected between the second terminal of its switching transistor and the negative transmission branch, or a voltage regulator 102 (as shown in the diagram) can be connected between the first terminal of its switching transistor and the positive transmission branch. Figure 3(as shown in the image); no limitation is made here, depending on the specific application environment, and all are within the scope of protection of this application.

[0088] In one example, under a common negative electrode structure, such as Figure 1 or Figure 2 As shown, the voltage regulator 102 can be connected between the switching transistor and the negative transmission branch in the first BOOST circuit 101. Specifically, the positive terminal of the voltage regulator 102 is connected to the second terminal of the switching transistor, and the negative terminal of the voltage regulator 102 is connected to the negative transmission branch. In a common positive structure, as shown... Figure 3 As shown, the voltage regulator 102 can be connected between the switching transistor and the positive transmission branch in the first BOOST circuit 101. Specifically, the positive terminal of the voltage regulator 102 is connected to the positive transmission branch, and the negative terminal of the voltage regulator 102 is connected to the first terminal of the switching transistor. Furthermore, when the number of first BOOST circuits 101 is greater than one, the switching transistors between the positive and negative transmission branches in each first BOOST circuit 101 can share the same voltage regulator 102, that is, they are all connected in series with the voltage regulator 102. Figure 2 Taking the illustrated example, switch S1 is connected in series with the voltage regulator 102 between the positive and negative transmission branches of the lowest first BOOST circuit 101; switch S2 is connected in series with the voltage regulator 102 between the positive and negative transmission branches of the middle first BOOST circuit 101; and so on, with switch S1 and the voltage regulator 102 connected in series between the positive and negative transmission branches of the highest first BOOST circuit 101. In this configuration, the number of voltage regulators 102 can be reduced, lowering costs.

[0089] This embodiment does not limit the number of the first BOOST circuit 101 and the voltage regulator 102 in the DC / DC converter circuit 10. That is, the number of the first BOOST circuit 101 can be greater than 1, and the number of the voltage regulator 102 can also be greater than 1. Moreover, there is no mutual influence between the two numbers, which allows the DC / DC converter circuit 10 to have various structures, such as:

[0090] (1) The number of voltage regulators 102 is 1, the number of first BOOST circuits 101 is greater than 1, and each first BOOST circuit 101 is connected in series with the voltage regulator 102.

[0091] That is, such as Figure 2 or Figure 3 As shown in the figure, this method can save the number of voltage regulators 102 to the greatest extent and reduce costs.

[0092] (2) The number of first BOOST circuits 101 is greater than 1, and there are at least two first BOOST circuits 101 connected to the same voltage regulator 102.

[0093] In practical applications, if the number N of the first BOOST circuits 101 is large, the first BOOST circuits 101 can be grouped together to share the voltage regulator 102. That is, the switching transistors between the positive and negative transmission branches of each first BOOST circuit 101 in each group are connected in series with the same voltage regulator 102, and the number of first BOOST circuits 101 in each group is not limited. As long as there are at least two first BOOST circuits 101 in a group and they share the same voltage regulator 102, at least one voltage regulator 102 can be saved, thereby reducing costs.

[0094] (3) The number of voltage regulators 102 is greater than 1, and there is at least one first BOOST circuit 101 connected to at least two voltage regulators 102.

[0095] At this time, the number of first BOOST circuits 101 can be one or more. As long as the switching transistor between the positive and negative transmission branches in one first BOOST circuit 101 is connected in series with at least two voltage regulators 102, the voltage regulators 102 connected to the corresponding switching transistors can be connected in parallel or in series, and the order of series connection is not limited. As long as there are voltage regulators 102 connected in series between the switching transistors between the positive and negative transmission branches, the ripple rate of the inductor current in the corresponding first BOOST circuit 101 can be reduced, and the voltage borne by the switching transistor can be reduced. It depends on the specific application environment, and all of them are within the protection scope of this application.

[0096] (4) The number of the first BOOST circuit 101 and the voltage regulator 102 is greater than 1, and the first BOOST circuit 101 and the voltage regulator 102 are connected in a one-to-one correspondence.

[0097] That is, the DC / DC converter circuit 10 may include at least two sets of... Figure 1 The structures shown in the figure include a first BOOST circuit 101 and a voltage regulator 102 in each group of structures; the output terminals of each first BOOST circuit 101 are connected in parallel; moreover, the series connection order between the voltage regulator 102 and the corresponding switching transistor in each group of structures is not limited, and the series connection order in different groups of structures can be the same or different, depending on the specific application environment, and all of them are within the protection scope of this application.

[0098] In addition, a corresponding capacitor (such as...) can be connected between the positive and negative terminals of the input of the first BOOST circuit 101. Figure 1 The Cin shown, or, as... Figure 2 or Figure 3The capacitors C1, C2, ..., CN shown in the diagram are used to filter and stabilize the input voltage of the first BOOST circuit 101. Additionally, the output of the DC / DC converter circuit 10 can also be connected to a corresponding capacitor (e.g., ...). Figures 1 to 3 The capacitor Cout shown in the figure is used to filter and stabilize the output voltage Vout of the first BOOST circuit 101. The capacitor Cout can belong to the DC / DC conversion circuit 10, or it can be connected between the positive and negative terminals of the DC bus. It can also be set in two different positions, depending on the specific application environment. All of these are within the protection scope of this application.

[0099] Due to the voltage division effect of the voltage regulator 102, the first BOOST circuit 101 connected to it only needs one power switching device, that is, the above-mentioned basic BOOST topology can be used; of course, the first BOOST circuit 101 can also use other two-level BOOST topologies or even three-level BOOST topologies, and can also choose inductors with smaller inductance values ​​and switching transistors with smaller withstand voltage, all of which are within the protection scope of this application. Figure 4 exist Figure 2 Based on this, the first BOOST circuit 101 using a three-level flying capacitor BOOST topology is used as an example for demonstration. This three-level flying capacitor BOOST topology includes: an inductor (such as...) Figure 4 The L1, L2, ..., LN shown in the diagram), and two switching transistors (such as... Figure 4 S1 and S1', S2 and S2', ..., SN and SN' shown) and two diodes (as shown) Figure 4 The diagram shows D1 and D1', D2 and D2', ..., DN and DN'. Two switching transistors are connected in series between the positive and negative transmission branches of the first BOOST circuit 101 as power switching devices. An inductor is placed between the input terminal of the first BOOST circuit 101 and the switching transistors. Two diodes are connected in series between the switching transistors and the output terminal of the first BOOST circuit 101. The transmission branches where the inductor and diodes are located are not limited.

[0100] This application does not limit the topology and structure of the first BOOST circuit 101, nor does it limit the quantitative correspondence between the first BOOST circuit 101 and the voltage regulator 102; these can be determined according to the specific application environment.

[0101] Based on the above embodiments, this embodiment provides a more detailed description of the DC / DC converter circuit 10. For example, its voltage regulator 102 can be implemented using any device capable of stably controlling the voltage at the corresponding location, i.e., there are multiple implementation forms, such as:

[0102] The voltage regulator 102 can be a voltage regulator chip; the output terminal of the voltage regulator chip is connected in series with the switching transistor between the positive and negative transmission branches in the corresponding first BOOST circuit 101; the output terminal of the voltage regulator chip includes positive and negative terminals, to... Figure 1 The structure shown is used as an example for explanation. The positive terminal of the output of the voltage regulator chip is connected to the second terminal of the switching transistor S, and the negative terminal of the output of the voltage regulator chip is connected to the negative transmission branch. Other structures and connection sequences will not be described in detail.

[0103] Alternatively, the voltage regulator 102 can also be a voltage-regulated load; the input terminal of the voltage-regulated load is connected in series with the switching transistor between the positive and negative transmission branches in the corresponding first BOOST circuit 101; the input terminal of the voltage-regulated load includes positive and negative terminals, so as to... Figure 1 The structure shown is used as an example for explanation. The positive input terminal of the voltage-regulated load is connected to the second terminal of the switching transistor S, and the negative input terminal of the voltage-regulated load is connected to the negative transmission branch. Other structures and connection sequences will not be described in detail.

[0104] Alternatively, the voltage regulator 102 may also include a second boost circuit, such as... Figure 5 The second BOOST circuit, shown as BOOST#0, has its input terminals (positive and negative) serving as the two ends of the voltage regulator 102, connected in series with the switching transistors in the positive and negative transmission branches of the first BOOST circuit 101. The output of the second BOOST circuit can be connected to the output of the DC / DC converter circuit 10 (e.g., ...). Figure 5 (as shown in the image).

[0105] in addition, Figure 5 The example shown uses the first BOOST circuit 101 with a two-level BOOST topology. In actual applications, the first BOOST circuit 101 can also use a three-level BOOST topology or other topologies, which will not be illustrated here.

[0106] In practical applications, this second BOOST circuit can be a two-level BOOST topology, such as the basic BOOST topology mentioned above. Figure 5 As shown, it specifically includes inductor L0, switching transistor S0, and diode D0. The connection relationships between the internal components are similar to those described above and will not be repeated here. Furthermore, this second BOOST circuit can also be a common negative terminal structure or a common positive terminal structure. Figure 5 The common negative terminal structure is used as an example for demonstration. Additionally, a corresponding capacitor C0 can also be placed between the positive and negative terminals of the input of this second BOOST circuit.

[0107] Figure 5 Taking the first BOOST circuit 101 as an example, which has two units and adopts a common negative terminal structure, its specific operating states include:

[0108] When the switching transistor S0 is turned on, it can form as follows: Figure 6 In the circuit indicated by the dashed arrow, inductor L0 is charged, and capacitor C0 in voltage regulator 102 is discharged.

[0109] When the switching transistor S0 is turned off, it can form as follows: Figure 7 In the circuit indicated by the dashed arrow, inductor L0 is discharging, and capacitor C0 in voltage regulator 102 is discharging.

[0110] When the switching transistor S1 is turned on, it can form as follows: Figure 8 The loop indicated by the dashed arrow shows the inductor L1 and the capacitor C0 in the voltage regulator 102 being charged.

[0111] When the switching transistor S1 is turned off, the following can be formed: Figure 9 The loop indicated by the dashed arrow shows inductor L1 discharging.

[0112] When the switching transistor S2 is turned on, it can form as follows: Figure 10 The loop indicated by the dashed arrow shows the inductor L2 and the capacitor C0 in the voltage regulator 102 being charged.

[0113] When switch S2 is turned off, it can form as follows Figure 11 The loop indicated by the dashed arrow shows inductor L2 discharging.

[0114] In practical photovoltaic inverter system applications, each power source 20 (e.g.) Figures 2 to 4 The Input#1, Input#2, ..., Input#N shown, or, Figure 5 When the input characteristics of Input#1 and Input#2 shown are not much different, a high-voltage, high-power regulated power supply 102 can be selected, so that each first BOOST circuit 101 can select devices with lower tolerance. The regulated power supply 102 can also be used to perform basic power control of MPPT, so that each first BOOST circuit 101 only needs to make a small adjustment to its input voltage to achieve MPPT for each power supply 20.

[0115] In particular, when the input characteristics of each power supply 20 are basically the same, the switching transistors between the positive and negative transmission branches in each first BOOST circuit 101 can be fully turned on, so that the DC / DC converter circuit 10 can achieve MPPT for all power supplies 20 through the voltage regulator 102 alone.

[0116] Therefore, the DC / DC converter circuit 10 provided in this embodiment has significant advantages in hardware selection and software control in application scenarios where the configuration differences of each power supply 20 are small.

[0117] In practical applications, the output of the second BOOST circuit can also be connected to a battery or load circuit (not shown in the figure), which is not limited here. This can be used to regulate the voltage of the battery or load circuit or to provide a suitable power supply voltage to the load circuit.

[0118] Alternatively, the second BOOST circuit can also be a three-level BOOST topology. Figure 12 In Figure 5 (Based on this, the second BOOST circuit is replaced with a three-level flying capacitor BOOST topology as an example for demonstration). In practical applications, the first BOOST circuit 101 and the second BOOST circuit can both adopt a three-level BOOST topology, which will not be illustrated here. The specific implementation of the first BOOST circuit 101 and the second BOOST circuit is not limited in this application. It depends on the specific application environment. As long as the ripple rate of the inductor current and the voltage borne by the switching transistor can be reduced, they are all within the protection scope of this application.

[0119] Based on the above embodiments, the DC / DC converter circuit 10 may further include: at least one unidirectional conducting device, such as... Figure 13 (in order to be in) Figure 2 (Based on the example shown) The diodes D11, D12, ..., D1N shown are connected in series with the switching transistors in the corresponding positive and negative transmission branches of the first BOOST circuit 101, as follows: Figure 13 As shown, diode D11 is connected in series with switch S1, diode D12 is connected in series with switch S2, ..., diode D1N is connected in series with switch SN; and the conduction direction of this unidirectional conducting device is the direction of the current flowing when the switch in the first BOOST circuit 101 it is connected to is controlled to conduct.

[0120] To prevent a short circuit or reverse connection fault at the input of one or more first BOOST circuits 101, which could lead to a short circuit in the voltage regulator 102 and further affect the safety of other first BOOST circuits 101, a corresponding unidirectional conducting device can be connected in series between the switching transistor and the voltage regulator 102 in each first BOOST circuit 101, such as... Figure 13 As shown, this is to prevent the voltage regulator 102 from short-circuiting due to the above-mentioned short-circuit or reverse connection fault, which could lead to even worse consequences.

[0121] Another embodiment of this application provides a control method for a DC / DC converter circuit, which includes at least one first BOOST circuit and at least one voltage regulator; the switching transistor between the positive and negative transmission branches in the first BOOST circuit is connected in series with the corresponding voltage regulator; the structure and principle of the DC / DC converter circuit can be found in the above embodiments, and will not be repeated here.

[0122] like Figure 14 As shown, the control method for this DC / DC converter circuit includes:

[0123] S101. Control the operation of the voltage regulator with the preset voltage as the target.

[0124] Specifically, S101 may include: a voltage control target with a preset voltage as the voltage regulator source, controlling the operation of the voltage regulator source so that it undertakes the preset portion of the input voltage of the first BOOST circuit to which it is connected.

[0125] Taking the application scenario of a photovoltaic inverter system as an example, the voltage regulator can be controlled to bear a preset part of the input voltage of the first BOOST circuit it is connected to, such as a larger part of the corresponding input voltage, so that the voltage regulator operates at the preset voltage or a certain range near it, thereby making the photovoltaic string connected to the first BOOST circuit move closer to its maximum power point.

[0126] Furthermore, when executing S101, for cases where at least two first BOOST circuits share the same voltage regulator, the voltage regulator is controlled to bear a preset portion of the input voltage of the first BOOST circuit it is connected to. Specifically, this process may include controlling the voltage of the voltage regulator to be the minimum input voltage of all the first BOOST circuits currently connected to it. That is, the preset voltage may refer to the minimum input voltage of each corresponding first BOOST circuit.

[0127] Alternatively, in photovoltaic inverter system applications, the MPP (Maximum Power Point) voltage of each photovoltaic string can be determined under different lighting conditions through prior experiments or real-time monitoring, based on the configuration of each string. For each lighting condition, a suitable voltage value, such as the minimum value, is selected from the MPP voltages of strings sharing the same voltage regulator and used as the preset value for that regulator under the corresponding lighting conditions, thus handling a larger portion of the MPP voltage. In other words, this preset voltage can also be the preset value corresponding to the current lighting conditions.

[0128] In practical applications, other methods can also be used to control the operation of the voltage regulator. These are just some optional examples and are not limited to these.

[0129] S101 enables the first BOOST circuit connected to the voltage regulator to achieve MPPT with lower power. This is applicable when the switching transistors between the positive and negative transmission branches of at least two first BOOST circuits are connected in series with the same voltage regulator, for example... Figure 2 , Figure 3 or Figure 4 As shown, the power corresponding to the above operation of the voltage regulator is also the sum of most of the power when each of the first BOOST circuits implements MPPT; thus, each of the first BOOST circuits can achieve MPPT with less power by sharing the same voltage regulator.

[0130] S102, Control the operation of the first BOOST circuit.

[0131] When the power supply connected to the input terminal of the first BOOST circuit includes one photovoltaic string or at least two photovoltaic strings connected in parallel, the specific objective of step S102 is to enable the first BOOST circuit to operate at the MPP of its connected power supply. In practical applications, the power supply connected to the input terminal of the first BOOST circuit may also include one battery cluster or at least two battery clusters connected in parallel; this is not limited here and depends on the specific application environment.

[0132] In practical applications, S102 can specifically include the following two cases:

[0133] (1) If the input voltage of the first BOOST circuit is greater than the voltage of the voltage regulator connected to the first BOOST circuit, then control the corresponding first BOOST circuit to adjust its own input voltage.

[0134] Taking an example where the power supply connected to the input terminal of the first BOOST circuit includes one photovoltaic string or at least two photovoltaic strings connected in parallel, under normal operating conditions, the first BOOST circuit is in MPPT mode, and its input voltage is the MPP voltage of the corresponding photovoltaic string connected to it. With the voltage regulator connected to the first BOOST circuit bearing most of its input voltage, by controlling the operation of the first BOOST circuit, the voltage after the series connection of its inductor and switching transistor can be changed, thereby fine-tuning the input voltage of the first BOOST circuit so that its input voltage equals the corresponding MPP voltage, thus enabling the first BOOST circuit to achieve MPPT.

[0135] In practical applications, controlling the first BOOST circuit to adjust its input voltage can employ various methods such as the perturbation and observation method, the incremental conductance method, and the constant voltage method. This embodiment does not limit the specific method by which the first BOOST circuit adjusts its input voltage; it can be determined according to the specific application environment, and all are within the scope of protection of this application. Moreover, the specific methods of the perturbation and observation method, the incremental conductance method, and the constant voltage method can be found in related technologies, and will not be elaborated here.

[0136] Controlling the first BOOST circuit to adjust its input voltage can specifically include controlling the chopping action of the switching transistors between the positive and negative transmission branches in the first BOOST circuit. For detailed control procedures, please refer to relevant technical documents; they will not be elaborated upon here.

[0137] (2) If there are at least two first BOOST circuits sharing the same voltage regulator and the input characteristics of each first BOOST circuit meet the preset consistency condition, or if the voltage of the voltage regulator connected to the first BOOST circuit is equal to the MPP voltage of the power supply connected to the first BOOST circuit, then the switching transistor between the positive and negative transmission branches in the corresponding first BOOST circuit is kept on.

[0138] In cases where the switching transistors between the positive and negative transmission branches in at least two first BOOST circuits are connected in series with the same voltage regulator, if the input characteristics of each photovoltaic string are basically the same, that is, if the preset consistency condition is met, then the switching transistors between the positive and negative transmission branches in each first BOOST circuit can be fully turned on, that is, each switching transistor can be controlled to be constantly turned on, thereby achieving MPPT for each photovoltaic string connected to it with the same voltage regulator, further reducing the control complexity of the software.

[0139] When the switching transistors between the positive and negative transmission branches in at least two first BOOST circuits are connected in series with the same voltage regulator, and if the input characteristics of the corresponding photovoltaic strings differ, the input voltage of the first BOOST circuit connected to the photovoltaic string with the worst input characteristics will be the lowest. The switching transistors between the positive and negative transmission branches in this first BOOST circuit can also be continuously turned on, as long as the voltage of the voltage regulator connected to this first BOOST circuit is set to the input voltage of this first BOOST circuit. This control method can also be used when a voltage regulator is connected to only one first BOOST circuit.

[0140] Even if the power source is not a photovoltaic string, the presence of this voltage regulator can still bear a portion of the input voltage of the first BOOST circuit it is connected to. Its control principle is similar and will not be described in detail here.

[0141] The control method for the DC / DC converter circuit provided in this embodiment allows the first BOOST circuit to have most of its power and input voltage handled by its connected voltage regulator, thereby reducing the ripple rate of the inductor current and the voltage across the switching transistor, allowing for the selection of lower-specification components for the inductor and switching transistor. When multiple first BOOST circuits share the same voltage regulator, this significantly reduces hardware costs while also lowering software control complexity.

[0142] Another embodiment of this application also provides a controller, such as Figure 15 As shown, the controller may include a memory 301 and a processor 302. The processor 302 may be connected to the DC / DC converter circuit 10 provided in the above embodiment and may drive the switching transistors in the DC / DC converter circuit 10.

[0143] The memory 301 can specifically be RAM (random access memory), flash memory, ROM (read only memory), EPROM (Electronic Programmable ROM, a type of non-volatile read-only memory), registers, hard disks, removable disks, etc.

[0144] The memory 301 is used to store computer instructions. When the computer instructions stored in the memory 301 are executed by the processor 302, the processor 302 can be used to execute the control method of the DC / DC conversion circuit described in any of the above embodiments. The memory 301 can also store data, such as preset voltage and other information involved in the above embodiments.

[0145] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, DSL (digital subscriber line)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available media can be magnetic media, such as floppy disks, hard disks, and magnetic tapes; or, the available media can be semiconductor media, such as SSDs (solid state disks); the available media can also be other media, without limitation.

[0146] Another embodiment of this application also provides a power converter, such as Figure 16 As shown, it includes: a controller 01 and a DC / DC converter circuit 10; wherein:

[0147] The input terminal of the DC / DC converter circuit 10 is used to connect at least one power supply. Figure 13 (Taking multiple power supply Input#1 to Input#N as an example for demonstration) 20, the input terminal of the DC / DC conversion circuit 10 can be provided with multiple interfaces, each interface is connected to one power supply 20. One power supply 20 may include one photovoltaic string or at least two photovoltaic strings connected in parallel, or one power supply 20 may also include one battery cluster or at least two battery clusters connected in parallel. There is no limitation here, it depends on the specific application environment.

[0148] The output of the DC / DC converter circuit 10 can be connected to the DC bus of the inverter system.

[0149] The specific structure and working principle of the DC / DC converter circuit 10 can be found in the above embodiments, and will not be repeated here.

[0150] In addition, the DC / DC converter circuit 10 is controlled by the controller 01; the controller 01 is used to execute the control method of the DC / DC converter circuit as described in any of the above embodiments; the specific process and principle of the control method of the DC / DC converter circuit can be found in the above embodiments, and will not be repeated here.

[0151] In practical applications, this power converter may also include Figure 17 The diagram shows a DC / AC converter circuit 30. The DC side of this DC / AC converter circuit 30 is connected to the output terminal of the DC / DC converter circuit 10. When multiple first BOOST circuits exist in the DC / DC converter circuit 10, the output terminals of each first BOOST circuit can be connected in parallel to the DC side of the DC / AC converter circuit 30 via a DC bus. The AC side of the DC / AC converter circuit 30 is used to connect to the power grid and / or load. The AC side of the DC / AC converter circuit 30 can be used to output three-phase AC power (as shown in the diagram) or single-phase AC power (not shown), both of which are within the scope of protection of this application. The DC / AC converter circuit 30 is controlled by a controller 01 to realize the inverter function of the electrical energy output by the DC / DC converter circuit 10.

[0152] Figure 16 The power converter shown in the diagram can be used as an intelligent combiner box in a photovoltaic inverter system, or as an energy storage DC / DC converter connected to the DC bus of the photovoltaic inverter in a photovoltaic-storage system. Figure 17 The power converter shown in the diagram can be used as a string inverter in a photovoltaic inverter system, or as an energy storage converter in an energy storage system or a photovoltaic-energy storage system; however, it is not limited to these and can be used depending on the specific application environment.

[0153] In practical applications, the controller 01 can be a single unit or it can include multiple communication-connected modules (such as...). Figure 18 or Figure 19 The control module 02 shown is as follows; Figure 18 or Figure 19 As shown, when the controller 01 includes multiple control modules 02, the voltage regulator 102 and the first BOOST circuit 101 in the DC / DC converter circuit 10 are respectively integrated with their respective control modules 02 in their respective device housings and are controlled by their respective control modules 02. For example, the first BOOST circuit 101 can be integrated with the corresponding control module 02 in one DC / DC converter, and when the voltage regulator 102 uses a second BOOST circuit, it can also be integrated with the corresponding control module 02 in another DC / DC converter. Figure 18 exist Figure 16 Based on this, the connection relationship of the first BOOST circuit 101 with a common negative structure is used as an example to illustrate the actual application, which is not limited to this.

[0154] In this case, Figure 17 The DC / AC conversion circuit 30 shown will also be integrated with the corresponding control module in the corresponding device housing, such as Figure 19 The DC / AC converter 31 shown is described; the control module inside the DC / AC converter 31 can communicate with each control module 02.

[0155] The power converter provided in this embodiment can reduce hardware costs by using the DC / DC conversion circuit 10 described in the above embodiment; and can reduce software control complexity by using the control method of the DC / DC conversion circuit described in the above embodiment.

[0156] Similar or identical parts between the various embodiments in this specification can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the description of the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment solution according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0157] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0158] The features described above regarding the disclosed embodiments can be substituted for or combined with each other to enable those skilled in the art to implement or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A DC / DC converter circuit, characterized in that, include: At least one first BOOST circuit and at least one voltage regulator; wherein, The input terminal of the first BOOST circuit is connected to the corresponding input interface of the DC / DC converter circuit; The output of the first BOOST circuit is connected to the output of the DC / DC converter circuit; In the first BOOST circuit, the switching transistor between the positive and negative transmission branches is connected in series with the corresponding voltage regulator.

2. The DC / DC converter circuit according to claim 1, characterized in that, The number of the first BOOST circuit and the voltage regulator is greater than 1, and the first BOOST circuit and the voltage regulator are connected in a one-to-one correspondence. Alternatively, the number of voltage regulators is greater than 1, and at least one of the first BOOST circuits is connected to at least two voltage regulators; Alternatively, the number of the first BOOST circuits is greater than 1, and there are at least two of the first BOOST circuits connected to the same voltage regulator; Alternatively, the number of voltage regulators is 1, the number of first BOOST circuits is greater than 1, and each first BOOST circuit is connected in series with the voltage regulator.

3. The DC / DC converter circuit according to claim 1, characterized in that, The voltage regulator includes: a voltage regulator chip; the output terminal of the voltage regulator chip is connected in series with the switching transistor between the positive and negative transmission branches in the corresponding first BOOST circuit; Alternatively, the voltage regulator includes: a voltage regulator load; the input terminal of the voltage regulator load is connected in series with the switching transistor between the positive and negative transmission branches in the corresponding first BOOST circuit; Alternatively, the voltage regulator may include: a second BOOST circuit; the input terminal of the second BOOST circuit is connected in series with the switching transistors between the corresponding positive and negative transmission branches in the first BOOST circuit.

4. The DC / DC converter circuit according to claim 3, characterized in that, The output terminal of the second BOOST circuit is connected to the output terminal of the DC / DC converter circuit; Alternatively, the output of the second BOOST circuit can be connected to a battery or load circuit.

5. The DC / DC converter circuit according to claim 3, characterized in that, The second BOOST circuit is either a two-level BOOST topology or a three-level BOOST topology.

6. The DC / DC converter circuit according to any one of claims 1 to 5, characterized in that, The first BOOST circuit is either a two-level BOOST topology or a three-level BOOST topology.

7. The DC / DC converter circuit according to any one of claims 1 to 5, characterized in that, Also includes: At least one unidirectional conducting device; The unidirectional conducting device is connected in series with the switching transistor between the positive and negative transmission branches in the corresponding first BOOST circuit. The conduction direction of the unidirectional conducting device is the direction of the current flowing when the connected switch is controlled to conduct.

8. The DC / DC converter circuit according to any one of claims 1 to 5, characterized in that, The positive input terminal of the first BOOST circuit is connected to the positive input terminal of the corresponding interface of the DC / DC converter circuit. The positive output terminal of the first BOOST circuit is connected to the positive output terminal of the DC / DC converter circuit. The negative input terminal and negative output terminal of the first BOOST circuit are connected to the negative input terminal and negative output terminal of the corresponding interface of the DC / DC converter circuit. The voltage regulator is connected between the switching transistor and the negative transmission branch in the positive and negative transmission branches of the first BOOST circuit. Alternatively, the negative input terminal of the first BOOST circuit is connected to the negative input terminal of the corresponding input interface of the DC / DC converter circuit, the negative output terminal of the first BOOST circuit is connected to the negative output terminal of the DC / DC converter circuit, the positive input terminal and the positive output terminal of the first BOOST circuit are connected to the positive input terminal and the positive output terminal of the corresponding input interface of the DC / DC converter circuit, and the corresponding voltage regulator is connected between the switching transistor and the positive transmission branch in the first BOOST circuit.

9. A control method for a DC / DC converter circuit, characterized in that, include: With a preset voltage as the target, the voltage regulator connected in series with the switching transistor in the DC / DC conversion circuit and the positive and negative transmission branch in the first BOOST circuit is controlled to operate; Control the operation of the first BOOST circuit.

10. The control method for the DC / DC converter circuit according to claim 9, characterized in that, The objective of controlling the operation of the first BOOST circuit is to make the first BOOST circuit operate at the maximum power point of the power supply it is connected to.

11. The control method for the DC / DC converter circuit according to claim 9, characterized in that, Controlling the operation of the first BOOST circuit includes: If the input voltage of the first BOOST circuit is greater than the voltage of the voltage regulator connected to the first BOOST circuit, then the first BOOST circuit is controlled to adjust its own input voltage. If at least two first BOOST circuits share the same voltage regulator and the input characteristics of each first BOOST circuit meet a preset consistency condition, or if the voltage of the voltage regulator connected to the first BOOST circuit is equal to the maximum power point voltage of the power supply connected to the first BOOST circuit, then the switching transistor between the positive and negative transmission branches in the first BOOST circuit is controlled to be constantly on.

12. The control method for the DC / DC converter circuit according to claim 11, characterized in that, Controlling the first BOOST circuit to adjust its own input voltage includes: Control the chopping action of the switching transistor between the positive and negative transmission branches in the first BOOST circuit.

13. The control method for the DC / DC converter circuit according to any one of claims 9 to 12, characterized in that, The operation of a voltage regulator connected in series with the switching transistor in the DC / DC converter circuit and the positive and negative transmission branches in the first BOOST circuit, with a preset voltage as the target, includes: Using the preset voltage as the voltage control target for the voltage regulator, the voltage regulator is controlled to operate so that it bears a preset portion of the input voltage of the first BOOST circuit to which it is connected.

14. The control method for the DC / DC converter circuit according to claim 13, characterized in that, When at least two of the first BOOST circuits share the same voltage regulator, the preset voltage is: The minimum input voltage of all the first BOOST circuits currently connected to the voltage regulator; Alternatively, if the power supply connected to the first BOOST circuit includes a photovoltaic module, the preset value corresponding to the current illumination conditions.

15. A controller, characterized in that, include: A processor and a memory, the memory being used to store programs, instructions, or code, and the processor being used to execute the programs, instructions, or code in the memory to perform the control method for the DC / DC conversion circuit as described in any one of claims 9 to 14.

16. A power converter, characterized in that, include: The controller and the DC / DC conversion circuit as described in any one of claims 1 to 8; wherein, The DC / DC conversion circuit is controlled by the controller; The controller is used to execute the control method for the DC / DC conversion circuit as described in any one of claims 9 to 14.

17. The power converter according to claim 16, characterized in that, Also includes: DC / AC conversion circuit; The DC side of the DC / AC conversion circuit is connected to the output terminal of the DC / DC conversion circuit; The AC side of the DC / AC conversion circuit is used to connect to the power grid and / or the load; The DC / AC conversion circuit is controlled by the controller.

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