A power conversion circuit and power supply system

Abstract

The application provides a power conversion circuit and a power supply system, which are applied to the technical field of power electronics. The circuit comprises a first power conversion sub-circuit, a second power conversion sub-circuit and an energy storage capacitor. The circuit alternately operates in a first mode or a second mode according to a driving signal. In the first mode, the first power conversion sub-circuit charges the energy storage capacitor, and the second power conversion sub-circuit cooperates with a power supply module to supply power to a power consumption load. In the second mode, the energy storage capacitor cooperates with the power supply module through the second power conversion sub-circuit to supply power to the power consumption load. The circuit realizes power transmission between the power supply module and the power consumption load through the alternation of the first mode and the second mode, and realizes power exchange through the energy storage capacitor, thereby replacing an isolation transformer arranged in the prior art, so that the overall cost of the power conversion circuit is effectively reduced, and the difficulty of wide popularization and application is reduced.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, specifically to a power conversion circuit and power supply system. Background Technology

[0002] In recent years, partial power conversion technology has been widely used because it can effectively solve a series of problems faced by DC-DC converters, such as efficiency, power density, cost and heat dissipation. The core of partial power conversion technology is to allow only a small part of the total system power to flow through the power conversion circuit, while the remaining main power is transmitted directly between the power supply and the load through the feedforward path, thereby reducing the losses generated by the power conversion circuit during the power conversion process.

[0003] However, the inventors discovered that most of the power conversion circuits provided by existing technologies achieve energy exchange through isolation transformers, such as flyback transformers and dual active bridges. These power conversion circuits have high overall costs due to the need to set up isolation converters, making it difficult to promote and apply them on a large scale. Summary of the Invention

[0004] In view of this, this application aims to provide a power conversion circuit and power supply system to solve the problems of high overall cost and difficulty in promotion and application of some power conversion circuits in the prior art.

[0005] In a first aspect, this application provides a power conversion circuit, comprising: a first power conversion sub-circuit, a second power conversion sub-circuit, and an energy storage capacitor, wherein...

[0006] The input port of the first power conversion sub-circuit is connected in parallel with the power supply port of the power supply module, and the output port of the first power conversion sub-circuit is connected in parallel with the energy storage capacitor and the input port of the second power conversion sub-circuit, respectively.

[0007] The output port of the second power conversion sub-circuit is connected in series with the power supply port to form a load port, which is used to connect an electrical load.

[0008] The power conversion circuit responds to the drive signal and alternately operates in the first mode or the second mode;

[0009] In the first mode, the first power conversion sub-circuit charges the energy storage capacitor, and the second power conversion sub-circuit works with the power supply module to supply power to the electrical load.

[0010] In the second mode, the energy storage capacitor supplies power to the electrical load through the second power conversion sub-circuit and the power supply module.

[0011] In an alternative implementation, in the second mode, the energy storage capacitor is also used to charge the second power conversion sub-circuit.

[0012] In an alternative implementation, in the second mode, the first power conversion sub-circuit is also used to store electrical energy.

[0013] In one optional implementation, the first power conversion sub-circuit includes a boost circuit and a first switching circuit, wherein,

[0014] The input port of the boost circuit serves as the input port of the first power conversion sub-circuit.

[0015] The positive output terminal of the boost circuit is connected to one end of the energy storage capacitor, and the other end of the energy storage capacitor is connected to one end of the first switching circuit.

[0016] The other end of the first switching circuit is connected to the negative output terminal of the output port of the boost circuit;

[0017] The control terminal of the first switching circuit is used to receive the drive signal;

[0018] In the first mode, the first switching circuit is turned on, and the boost circuit charges the energy storage capacitor;

[0019] In the second mode, the first switching circuit is turned off, and the energy storage capacitor is discharged.

[0020] In one optional embodiment, the boost circuit includes a first inductor, a first unidirectional conduction circuit, and a second switching circuit, wherein,

[0021] One end of the first inductor serves as the positive input terminal of the input port of the boost circuit, and the other end of the first inductor is connected to one end of the first unidirectional conduction circuit and one end of the second switching circuit, respectively.

[0022] The other end of the first unidirectional conduction circuit serves as the positive output terminal of the output port of the boost circuit;

[0023] The other end of the second switching circuit serves as the negative output terminal of the output port and the negative input terminal of the input port of the boost circuit. The control terminal of the second switching circuit is used to receive the drive signal.

[0024] In the first mode, the second switching circuit is turned off;

[0025] In the second mode, the second switching circuit is turned on;

[0026] The conduction direction of the first unidirectional conduction circuit is the same as the charging direction of the energy storage capacitor.

[0027] In one optional embodiment, the first switching circuit includes a first switching transistor and a second unidirectional conduction circuit, wherein,

[0028] The first switching transistor and the second unidirectional conduction circuit are connected in series to form a series branch;

[0029] One end of the series branch is connected to the energy storage capacitor, and the other end of the series branch is connected to the negative output terminal of the output port of the boost circuit.

[0030] The control terminal of the first switching transistor is used to receive the drive signal;

[0031] The conduction direction of the second unidirectional conduction circuit is the same as the charging direction of the energy storage capacitor.

[0032] In one optional implementation, the second power conversion sub-circuit includes a buck circuit and a third switching circuit, wherein,

[0033] The output port of the step-down circuit serves as the output port of the second power conversion sub-circuit.

[0034] The positive input terminal of the input port of the step-down circuit is connected to one end of the energy storage capacitor, and the other end of the energy storage capacitor is connected to one end of the third switching circuit.

[0035] The other end of the third switching circuit is connected to the negative input terminal of the input port of the step-down circuit;

[0036] In the first mode, the third switching circuit is turned off and the buck circuit is discharged.

[0037] In the second mode, the third switching circuit is turned on, and the step-down circuit is charged.

[0038] In one optional embodiment, the step-down circuit includes a fourth switching circuit, a second inductor, a third unidirectional conduction circuit, and a filter capacitor, wherein,

[0039] One end of the fourth switching circuit serves as the positive input terminal of the step-down circuit, and the other end of the fourth switching circuit is connected to one end of the second inductor and one end of the third unidirectional conduction circuit, respectively.

[0040] The other end of the second inductor is connected to one end of the filter capacitor, and the other end of the filter capacitor is connected to the other end of the third unidirectional conduction circuit.

[0041] The connection point between the third unidirectional conduction circuit and the filter capacitor serves as the negative input terminal of the step-down circuit.

[0042] The two ends of the filter capacitor serve as the output ports of the step-down circuit.

[0043] The control terminal of the fourth switching circuit is used to receive the drive signal;

[0044] In the first mode, the fourth switching circuit is turned off;

[0045] In the second mode, the fourth switching circuit is turned on;

[0046] The conduction direction of the third unidirectional conduction circuit is opposite to the charging direction of the energy storage capacitor.

[0047] In one optional embodiment, the third switching circuit includes a fourth unidirectional conduction circuit, and the conduction direction of the fourth unidirectional conduction circuit is opposite to the charging direction of the energy storage capacitor.

[0048] In one optional embodiment, the power conversion circuit provided in the first aspect of this application further includes: a controller, wherein,

[0049] The controller is connected to the first power conversion sub-circuit and the second power conversion sub-circuit respectively;

[0050] The controller is used to output the drive signal.

[0051] Secondly, this application provides a power supply system, comprising: a power supply module and a power conversion circuit as described in any of the first aspects of this application, wherein,

[0052] The power supply module supplies power to the electrical load through the power conversion circuit.

[0053] In one alternative implementation, the power supply module includes a photovoltaic module or an energy storage battery.

[0054] Based on the above, the power conversion circuit provided in this application includes a first power conversion sub-circuit, a second power conversion sub-circuit, and an energy storage capacitor. The input port of the first power conversion sub-circuit is connected in parallel with the power supply port of the power supply module. The output port of the first power conversion sub-circuit is connected in parallel with both the energy storage capacitor and the input port of the second power conversion sub-circuit. The output port of the second power conversion sub-circuit is connected in series with the power supply port to form a load port, which is connected to the electrical load. The power conversion circuit provided in this application operates alternately in a first mode or a second mode according to a drive signal: In the first mode, the first power conversion sub-circuit charges the energy storage capacitor, and the second power conversion sub-circuit, together with the power supply module, supplies power to the electrical load; in the second mode, the energy storage capacitor, through the second power conversion sub-circuit, together with the power supply module, supplies power to the electrical load. Thus, the power conversion circuit provided in this application achieves power transmission between the power supply module and the electrical load through the alternating operation of the first and second modes, and realizes energy exchange through the energy storage capacitor, replacing the isolation transformer set in the prior art, thereby effectively reducing the overall cost of the power conversion circuit and reducing the difficulty of large-scale promotion and application. Attached Figure Description

[0055] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0056] Figure 1a This is a schematic diagram of the full-power transmission process in existing technology.

[0057] Figure 1b This is a schematic diagram of a portion of the power transfer process in existing technology.

[0058] Figure 2 This application provides a structural block diagram of a power conversion circuit.

[0059] Figure 3 This is a topology diagram of a power conversion circuit provided in this application.

[0060] Figure 4 This is a schematic diagram of the power flow direction of the power conversion circuit provided in this application operating in the first mode.

[0061] Figure 5 This is a schematic diagram of the power flow direction of the power conversion circuit provided in this application operating in the second mode.

[0062] Figure 6 This is a structural block diagram of a power supply system provided in this application. Detailed Implementation

[0063] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. 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.

[0064] In recent years, DC-DC conversion technology has developed rapidly. On the one hand, DC distribution networks have been built one after another. Compared with traditional AC distribution networks, DC distribution networks have advantages such as large power supply capacity, high operating efficiency, high reliability, and strong ability to accommodate distributed power sources, and have broad development prospects. On the other hand, the number of DC ports for photovoltaic power generation, battery energy storage, and new energy vehicles has surged, which greatly benefits the development of the DC converter industry.

[0065] Figure 1a This example demonstrates the power processing of full-power transmission in DC-DC conversion technology. Here, Pin refers to the total input power of the full-power conversion circuit, while Pout refers to the total output power of the full-power conversion circuit. During the power transmission process, power loss Ploss will inevitably occur due to the impedance of the components in the full-power conversion circuit itself.

[0066] Correspondingly, Figure 1b The diagram illustrates the power processing steps of partial power transfer. Its core principle is to ensure that only a small portion of the total system power flows through the power conversion circuit, while the remaining main power is transferred directly between the power source and the load via a feedforward path. This ensures that most of the power reaches its destination with virtually no loss. It's understandable that because only a small portion of the power needs to be transferred through the power conversion circuit, compared to… Figure 1a The full-power transmission scheme shown can significantly reduce the loss Ploss caused by the internal components of the power conversion circuit, thereby improving the energy utilization efficiency of the entire system and effectively solving a series of problems and challenges faced by the full-power transmission scheme, such as efficiency, power density, cost, and heat dissipation.

[0067] However, the inventors discovered that most of the power conversion circuits provided by existing technologies achieve energy exchange through isolation transformers, such as flyback transformers and dual active bridges. These power conversion circuits have high overall costs due to the need to set up isolation converters, making it difficult to promote and apply them on a large scale.

[0068] To address the aforementioned issues, this application provides a power conversion circuit that alternates between a first mode and a second mode: In the first mode, a first power conversion sub-circuit charges an energy storage capacitor, while a second power conversion sub-circuit, in conjunction with a power supply module, supplies power to the electrical load; in the second mode, the energy storage capacitor, through the second power conversion sub-circuit and the power supply module, supplies power to the electrical load. By alternating between the first and second modes, power is transferred between the power supply module and the electrical load, and energy exchange is achieved through the energy storage capacitor, replacing the isolation transformer used in existing technologies. This effectively reduces the overall cost of the power conversion circuit and lowers the difficulty of widespread application.

[0069] See Figure 2 The power conversion circuit provided in this application includes: a first power conversion sub-circuit 10, a second power conversion sub-circuit 20, and an energy storage capacitor C1.

[0070] Combination Figure 2 As shown, the input port of the first power conversion sub-circuit 10 is connected in parallel with the power supply port of the power supply module P0. The output port of the first power conversion sub-circuit 10 is connected in parallel with the energy storage capacitor C1 and the input port of the second power conversion sub-circuit 20, respectively. That is, the output terminal of the first power conversion sub-circuit 10 is connected to the input port of the second power conversion sub-circuit 20, and the energy storage capacitor C1 is connected between the two connection points of the first power conversion sub-circuit 10 and the second power conversion sub-circuit 20.

[0071] The output port of the second power conversion sub-circuit 20 is connected in series with the power supply port of the power supply module P0, combined with Figure 2 As shown, the power supply port of the power supply module P0 includes two power supply terminals. Correspondingly, the output port of the second power conversion sub-circuit 20 also includes two output terminals. Based on this, one power supply terminal of the power supply port of the power supply module P0 serves as the first load terminal out1, and the other power supply terminal is connected to one output terminal of the second power conversion sub-circuit 20. The other output terminal of the second power conversion sub-circuit 20 serves as the second load terminal out2. The first load terminal out1 and the second load terminal out2 together constitute the load port, and the electrical load Rs is connected between the first load terminal out1 and the second load terminal out2.

[0072] It should be noted that in practical applications, the power supply module P0 can be of various types. For example, it can be an energy storage battery, a photovoltaic power generation module, or other power supply modules that can provide DC power and need to perform power conversion with the electrical load. These will not be detailed here.

[0073] Based on the above connection relationship, the power conversion circuit provided in this application includes two operating modes, namely a first mode and a second mode. The power conversion circuit responds to a drive signal and alternately operates in either the first mode or the second mode. In one optional embodiment, the aforementioned drive signal is provided by a host computer, which is connected to the control terminals of both the first power conversion sub-circuit 10 and the second power conversion sub-circuit 20. The host computer controls the power conversion circuit to alternately operate in either the first mode or the second mode. In another optional embodiment, the power conversion circuit provided in this application further includes a controller, which is connected to the control terminals of both the first power conversion sub-circuit 10 and the second power conversion sub-circuit 20. The controller provides the aforementioned drive signal and controls the power conversion circuit to alternately operate in either the first mode or the second mode. The specific form of the drive signal will be discussed in detail in subsequent embodiments and will not be elaborated here.

[0074] In the first mode, the power supply module P0 charges the energy storage capacitor C1 through the first power conversion sub-circuit 10 so that the energy storage capacitor C1 stores electrical energy. At the same time, the second power conversion sub-circuit 20 works with the power supply module P0 to supply power to the electrical load Rs.

[0075] In the second mode, the energy storage capacitor C1, together with the power supply module P0, supplies power to the electrical load Rs through the second power conversion sub-circuit 20.

[0076] Combining the above content and Figure 2 As shown in the connection relationship, the power supply module P0 is directly connected to the electrical load Rs. When the power conversion circuit provided in this embodiment is used for power conversion and transmission, the main power is directly output from the power supply module P0 to the electrical load Rs. This part of the power can reach the electrical load Rs with almost no loss. The other part of the power that needs to be converted is transmitted by the power conversion circuit provided in this application. The power exchange is mainly completed by the energy storage capacitor, eliminating the isolation transformer in the prior art. Furthermore, since the power transmitted through the power conversion circuit is relatively small, the loss generated by the power conversion circuit itself is very small.

[0077] Furthermore, in the second mode, while the energy storage capacitor C1 supplies power to the electrical load Rs through the second power conversion sub-circuit 20, it can also charge the second power conversion sub-circuit 20, enabling it to supply power to the electrical load Rs in the first mode in conjunction with the power supply module P0. Based on this, it can be understood that for the second power conversion sub-circuit 20, during any complete power-on cycle, when it first enters the first mode, since it has not yet undergone the second mode charging process by the energy storage capacitor C1, it cannot supply power to the electrical load Rs. Instead, it serves as a power transmission path, working with the power supply module P0 and the electrical load Rs to form a complete power transmission path. Correspondingly, when not entering the first mode for the first time, having already undergone the charging and energy storage process of the second mode, the second power conversion sub-circuit 20 can simultaneously transmit power to the electrical load Rs while acting as a power transmission path, thus cooperating with the power supply module P0 to supply power to the electrical load Rs.

[0078] In summary, the power conversion circuit provided in this application, while taking into account the technical advantage of low loss, achieves power transmission between the power supply module and the electrical load through the alternating operation of the first and second modes, and realizes energy exchange through energy storage capacitors, replacing the isolation transformer set in the prior art, thereby effectively reducing the overall cost of the power conversion circuit and reducing the difficulty of large-scale promotion and application.

[0079] The following section describes the implementation and operation of the power conversion circuit provided in this application, using a specific circuit topology as an example.

[0080] See Figure 3 As an optional implementation, in the power conversion circuit provided in this embodiment, the first power conversion sub-circuit 10 includes a boost circuit 110 and a first switching circuit 120, and the second power conversion sub-circuit 20 includes a buck circuit 210 and a third switching circuit 220.

[0081] Combination Figure 3 As shown, the boost circuit 110 includes a first inductor L1, a first unidirectional conduction circuit, and a second switching circuit. The conduction direction of the first unidirectional conduction circuit is the same as the charging direction of the energy storage capacitor C1. In this embodiment, the first unidirectional conduction circuit is implemented using a first diode D1. In another optional embodiment, the first unidirectional conduction circuit can also be implemented using a controllable switch. The unidirectional conduction function is achieved by controlling the conduction state of the controllable switch. Of course, other circuits that can meet the unidirectional conduction requirements can also be selected, which will not be listed here. As long as they do not exceed the core concept of this application, they also fall within the scope of protection of this application. Furthermore, the second switching circuit is implemented using a second switch Q2.

[0082] The input port of the boost circuit 110 serves as the input port of the first power conversion sub-circuit 10, specifically including a positive input terminal and a negative input terminal. The output port of the boost circuit 110 includes a positive output terminal and a negative output terminal. Further, based on the specific configuration of the boost circuit 110 described above, one end of the first inductor L1 serves as the positive input terminal of the boost circuit 110, connected to the positive power supply terminal in the power supply port of the power supply module 10. The other end of the first inductor L1 is connected to one end of the first unidirectional conduction circuit (i.e., the anode of the first diode D1) and one end of the second switching circuit (i.e., one end of the second switching transistor Q2). The other end of the first unidirectional conduction circuit (i.e., the cathode of the first diode D1) serves as the positive output terminal of the boost circuit 110, connected to one end of the energy storage capacitor C1. The other end of the second switching circuit (i.e., the other end of the second switching transistor Q2) serves as the negative output terminal of the boost circuit 110 and is connected to the first switching circuit 120. Simultaneously, it also serves as the negative input terminal of the boost circuit 110 and is connected to the negative power supply terminal of the power supply module P0. The control terminal of the second switching circuit receives the aforementioned drive signal and turns on or off in response to the received drive signal.

[0083] The first switching circuit 120 includes a first switching transistor Q1 and a second unidirectional conduction circuit, wherein the conduction direction of the second unidirectional conduction circuit is the same as the charging direction of the energy storage capacitor C1. Figure 3 In the illustrated embodiment, the second unidirectional conduction circuit is implemented using the second diode D2. In another optional embodiment, the second unidirectional conduction circuit can also be implemented using a controllable switch. The unidirectional conduction function is achieved by controlling the conduction state of the controllable switch. Of course, other circuits that can meet the unidirectional conduction requirements can also be selected, which will not be listed here. As long as they do not exceed the core idea of ​​this application, they also fall within the scope of protection of this application.

[0084] Specifically, the first switch Q1 and the second diode D2 are connected in series to form a series branch. One end of the resulting series branch serves as one end of the first switch circuit 120 and is connected to the energy storage capacitor C1. The other end of the series branch serves as the other end of the first switch circuit 120 and is connected to the negative output terminal of the boost circuit 110. The control terminal of the first switch Q1 serves as the control terminal of the first switch circuit 120 and receives the drive signal. The first switch circuit 120 is turned on or off in response to the received drive signal.

[0085] Furthermore, the step-down circuit 210 includes a fourth switching circuit, a second inductor L2, a third unidirectional conduction circuit, and a filter capacitor C2. The fourth switching circuit is implemented using a third switching transistor Q3. The conduction direction of the third unidirectional conduction circuit is opposite to the charging direction of the energy storage capacitor C1. In this embodiment, the third unidirectional conduction circuit is implemented using a third diode D3. In another optional embodiment, the first unidirectional conduction circuit can also be implemented using a controllable switching transistor. The unidirectional conduction function is achieved by controlling the conduction state of the controllable switching transistor. Of course, other circuits that can meet the unidirectional conduction requirements can also be selected, which will not be listed here. As long as they do not exceed the core idea of ​​this application, they also fall within the scope of protection of this application.

[0086] Referring to the foregoing, the input ports of the second power conversion sub-circuit 20 include a positive input terminal and a negative input terminal, and correspondingly, the output ports include a positive output terminal and a negative output terminal. Based on this, one end of the fourth switching circuit (i.e., one end of the third switching transistor Q3) serves as the positive input terminal of the buck circuit 210, which is also the positive input terminal of the second power conversion sub-circuit 20, and is connected to the energy storage capacitor C1 and the positive output terminal of the first power conversion sub-circuit 10. The other end of the fourth switching circuit (i.e., the other end of the third switching transistor Q3) is connected to one end of the second inductor L2 and the cathode of the third diode D3, respectively. The fourth switching circuit is turned on or off in response to the aforementioned drive signal. The other end of the second inductor L2 is connected to one end of the filter capacitor C2, and the other end of the filter capacitor C2 is connected to the anode of the third diode D3. The two ends of the filter capacitor C1 serve as the output ports of the buck circuit 210, which is also the output ports of the second power conversion sub-circuit 20. The connection point between the third unidirectional conduction circuit (i.e., the third diode D3) and the filter capacitor C2 serves as the negative input terminal of the step-down circuit 210 (which can also be regarded as the negative output terminal of the step-down circuit 210), and is connected to one end of the third switching circuit 220. The other end of the third switching circuit 220 serves as the negative input terminal of the second power conversion sub-circuit 20 and is connected to the energy storage capacitor C1.

[0087] As an optional implementation, the third switching circuit 220 includes a fourth unidirectional conduction circuit, the conduction direction of which is opposite to the charging direction of the energy storage capacitor. Figure 3In the illustrated embodiment, the fourth unidirectional conduction circuit is implemented using a fourth diode D4. The anode of the fourth diode D4 serves as one end of the fourth unidirectional conduction circuit, i.e., one end of the third switching circuit 220, and is connected to the negative input terminal of the step-down circuit 210. The cathode of the fourth diode D4 serves as the other end of the fourth unidirectional conduction circuit, i.e., the other end of the third switching circuit 220, and is connected to the energy storage capacitor C1. In another optional embodiment, the fourth unidirectional conduction circuit can also be implemented using a controllable switch transistor. The unidirectional conduction function is achieved by controlling the conduction state of the controllable switch transistor. Of course, other circuits that can meet the unidirectional conduction requirements can also be selected, which will not be listed here. As long as they do not exceed the core concept of this application, they also fall within the scope of protection of this application.

[0088] The connection relationships between the first power conversion sub-circuit 10 and the second power conversion sub-circuit 20, the power supply module P0, and the electrical load Rs, etc., can be referred to the above content and will not be repeated here.

[0089] It should be noted that the switching transistors mentioned above can be selected in various ways in practical applications. For example, IGBT (Insulated-Gate Bipolar Transistor) or MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) can be selected. Of course, other types of controllable switching transistors can also be selected, which will not be listed here.

[0090] The following is combined with Figure 4 as well as Figure 5 The diagram illustrates the operation of the power conversion circuit provided in this embodiment in both the first and second modes. It should be noted that, for ease of demonstrating the power transmission direction, [the diagram is missing from the original text]. Figure 4 as well as Figure 5 In the example shown, components in the off state are represented in gray, and components in the on or running state are represented in black.

[0091] See Figure 4When the power conversion circuit is in the first mode in response to the drive signal, the first switch Q1 in the first power conversion sub-circuit 10 is turned on, a positive voltage is applied across the second diode D2, the first switch circuit 120 is turned on, the second switch Q2 in the boost circuit 110 is turned off, and further, the third switch Q3 in the buck circuit 210 in the second power conversion sub-circuit 20 is turned off, the third diode D3 in the buck circuit 210 is turned on, and the third switch circuit 220 (i.e., the fourth diode D4) is turned off. Based on the foregoing, the first inductor L1, the first diode D1, the energy storage capacitor C1, the first switch Q1, the second diode D2, and the power supply module P0 form a closed loop to charge the energy storage capacitor C1. At the same time, the power supply module P0, the electrical load Rs, the third diode D3, the filter capacitor C2, and the second inductor L2 form a closed loop. When the first inductor L1 and the second inductor L2 have stored electrical energy, they will also discharge to the outside. The electrical energy provided by the second inductor L2, together with the power supply module P0, supplies power to the electrical load Rs. In this process, the filter capacitor C2 can also filter out the AC component in the second inductor L2, thereby providing high-quality DC power to the electrical load Rs.

[0092] When the power conversion circuit is in the second mode in response to the drive signal, the first switching circuit 120 in the first power conversion sub-circuit 10 is in the off state, that is, both the first switch Q1 and the second diode D2 are in the off state. The second switching circuit (i.e., the second switch Q2) in the boost circuit 110 is turned on in response to the drive signal. The fourth switching circuit (i.e., the third switch Q3) in the boost circuit 210 of the second power conversion sub-circuit 20 is turned off in response to the drive signal, the third diode D3 is turned off, and the fourth diode D4 is turned on. For the first diode D1 in the boost circuit 110, in this case, its anode voltage is the voltage of the filter capacitor C2, and the cathode voltage is the sum of the voltage of the filter capacitor C2 and the voltage of the power supply module P0, that is, the anode voltage is less than the cathode voltage, so the first diode D1 is in the off state. Figure 5 As shown, the power supply module P0, the first inductor L1, and the second switch Q2 form a closed loop. The power supply module P0 charges the first inductor L1, which in turn charges the step-down circuit 210. Furthermore, the power supply module P0, the electrical load Rs, the filter capacitor C2, the fourth diode D4, the energy storage capacitor C1, the third switch Q3, and the second inductor L2 form a closed loop. The energy storage capacitor C1 discharges, charging the second inductor L2 while simultaneously working with the power supply module P0 to supply power to the electrical load Rs. Referring to the aforementioned description, the AC component of the current flowing through the second inductor L2 is filtered out by the filter capacitor C2.

[0093] Assume the voltage of power supply module P0 is V. bat V bat The voltage across the first inductor L1 is v.L1 v L1 The current in the first inductor L1 is i L1 i L1 The voltage v of the second inductor L2 L2 v L2 The current in the second inductor L2 is i L2 i L2 The voltage across the energy storage capacitor C1 is v. C1 v C1 The current in the energy storage capacitor C1 is i C1 i C1 The voltage across the filter capacitor C2 is v. C2 v C2 The current in the filter capacitor C2 is i C2 i C2 The period of the drive signal is T s T s The corresponding duty cycle is D, and D ′ =1―DD ′ =1―D.

[0094] Based on the above, the duration of the power conversion circuit in the first mode is D. ′ T s D ′ T s Correspondingly, the duration in the second mode is DT. s DT s By approximating the inductor current and capacitor voltage with small ripple and applying volt-second balance and ampere-second balance, the following relationship can be obtained:

[0095] For v L1 Existence: V bat D+(V bat ―V C1 )D ′ =0

[0096] For v L2 ≥Existence: (V) C1 ―V C2 )D+(―V C2 )D ′ =0

[0097] For i C1 ≥Existence:―I L2 D+I L1 D ′ =0

[0098] For i C2 exist: For i C2 exist:

[0099] Solving the above formula, we can obtain... V C1 =V bat +V C2 V C1 =V bat

[0100] +V C2 ,

[0101] Therefore, V can be changed by altering the duty cycle of the drive signal. C2 With V bat The size relationship between them, V C2 It can be greater than V bat It can also be less than V. bat Therefore, the power conversion circuit provided in this application can achieve both voltage boost and voltage buck. Furthermore, V C1 =V bat +V C2 V C1 =V bat +V C2 Because of V bat +V C2 V bat +V C2 The voltage supplied to the electrical load Rs is the same as the voltage of the energy storage capacitor C1. Therefore, it can be concluded that the voltage of the energy storage capacitor C1 is the same as the voltage of the electrical load Rs.

[0102] This application also provides a power supply system, including a power supply module and the power conversion circuit provided in any of the foregoing embodiments, combined with... Figure 6 As shown, the power supply module P0 is connected to the power conversion circuit and the load Rs provided in this application. The power supply module P0 can supply power to the electrical load Rs through the power conversion circuit. The specific power transmission process can be found in the aforementioned embodiments and will not be repeated here. As mentioned earlier, in practical applications, the power supply module can be a photovoltaic module or an energy storage battery. Of course, other power supply modules that can provide DC power and need to perform power conversion with the electrical load can also be used, which will not be described in detail here.

[0103] Those skilled in the art will understand that the contents disclosed herein can be varied and modified in many ways. For example, the various devices or components described above can be implemented in hardware, or in software, firmware, or a combination of some or all of the three.

[0104] Furthermore, while this disclosure makes various references to certain elements of systems according to embodiments of this disclosure, any number of different elements may be used and operated on clients and / or servers. Elements are merely illustrative, and different aspects of the system and method may use different elements.

[0105] This disclosure uses flowcharts to illustrate the steps of a method according to embodiments of this disclosure. It should be understood that the preceding or following steps are not necessarily performed in exact order. Instead, the steps can be processed in reverse order or simultaneously. Furthermore, other operations can be added to these processes.

[0106] Those skilled in the art will understand that all or part of the steps in the above methods can be implemented by a computer program instructing related hardware, and the program can be stored in a computer-readable storage medium, such as a read-only memory. Optionally, all or part of the steps in the above embodiments can also be implemented using one or more integrated circuits. Accordingly, each module / unit in the above embodiments can be implemented in hardware or as a software functional module. This disclosure is not limited to any particular combination of hardware and software.

[0107] Unless otherwise defined, all terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It should also be understood that terms such as those defined in a common dictionary should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and not as having an idealized or highly formalized meaning, unless expressly defined herein.

[0108] The foregoing description is intended to illustrate the present disclosure and should not be construed as limiting it. While several exemplary embodiments of the present disclosure have been described, those skilled in the art will readily understand that many modifications may be made to the exemplary embodiments without departing from the novel teachings and advantages of the present disclosure. Therefore, all such modifications are intended to be included within the scope of the present disclosure as defined by the claims. It should be understood that the foregoing description is intended to illustrate the present disclosure and should not be construed as limiting it to the specific embodiments disclosed, and modifications to the disclosed embodiments and other embodiments are intended to be included within the scope of the appended claims. The present disclosure is defined by the claims and their equivalents.

Claims

1. A power conversion circuit, characterized in that, include: The circuit consists of a first power conversion sub-circuit, a second power conversion sub-circuit, and an energy storage capacitor. The input port of the first power conversion sub-circuit is connected in parallel with the power supply port of the power supply module, and the output port of the first power conversion sub-circuit is connected in parallel with the energy storage capacitor and the input port of the second power conversion sub-circuit, respectively. The output port of the second power conversion sub-circuit is connected in series with the power supply port to form a load port, which is used to connect an electrical load. The power conversion circuit responds to the drive signal and alternately operates in the first mode or the second mode; In the first mode, the first power conversion sub-circuit charges the energy storage capacitor, and the second power conversion sub-circuit works with the power supply module to supply power to the electrical load. In the second mode, the energy storage capacitor supplies power to the electrical load through the second power conversion sub-circuit and the power supply module.

2. The power conversion circuit according to claim 1, characterized in that, In the second mode, the energy storage capacitor is also used to charge the second power conversion sub-circuit.

3. The power conversion circuit according to claim 1, characterized in that, In the second mode, the first power conversion sub-circuit is also used to store electrical energy.

4. The power conversion circuit according to claim 1, characterized in that, The first power conversion sub-circuit includes a boost circuit and a first switching circuit, wherein, The input port of the boost circuit serves as the input port of the first power conversion sub-circuit. The positive output terminal of the boost circuit is connected to one end of the energy storage capacitor, and the other end of the energy storage capacitor is connected to one end of the first switching circuit. The other end of the first switching circuit is connected to the negative output terminal of the output port of the boost circuit; The control terminal of the first switching circuit is used to receive the drive signal; In the first mode, the first switching circuit is turned on, and the boost circuit charges the energy storage capacitor; In the second mode, the first switching circuit is turned off, and the energy storage capacitor is discharged.

5. The power conversion circuit according to claim 4, characterized in that, The boost circuit includes a first inductor, a first unidirectional conduction circuit, and a second switching circuit, wherein... One end of the first inductor serves as the positive input terminal of the input port of the boost circuit, and the other end of the first inductor is connected to one end of the first unidirectional conduction circuit and one end of the second switching circuit, respectively. The other end of the first unidirectional conduction circuit serves as the positive output terminal of the output port of the boost circuit; The other end of the second switching circuit serves as the negative output terminal of the output port and the negative input terminal of the input port of the boost circuit. The control terminal of the second switching circuit is used to receive the drive signal. In the first mode, the second switching circuit is turned off; In the second mode, the second switching circuit is turned on; The conduction direction of the first unidirectional conduction circuit is the same as the charging direction of the energy storage capacitor.

6. The power conversion circuit according to claim 4, characterized in that, The first switching circuit includes a first switching transistor and a second unidirectional conduction circuit, wherein, The first switching transistor and the second unidirectional conduction circuit are connected in series to form a series branch; One end of the series branch is connected to the energy storage capacitor, and the other end of the series branch is connected to the negative output terminal of the output port of the boost circuit. The control terminal of the first switching transistor is used to receive the drive signal; The conduction direction of the second unidirectional conduction circuit is the same as the charging direction of the energy storage capacitor.

7. The power conversion circuit according to claim 1, characterized in that, The second power conversion sub-circuit includes a buck circuit and a third switching circuit, wherein, The output port of the step-down circuit serves as the output port of the second power conversion sub-circuit. The positive input terminal of the input port of the step-down circuit is connected to one end of the energy storage capacitor, and the other end of the energy storage capacitor is connected to one end of the third switching circuit. The other end of the third switching circuit is connected to the negative input terminal of the input port of the step-down circuit; In the first mode, the third switching circuit is turned off and the buck circuit is discharged. In the second mode, the third switching circuit is turned on, and the step-down circuit is charged.

8. The power conversion circuit according to claim 7, characterized in that, The step-down circuit includes a fourth switching circuit, a second inductor, a third unidirectional conduction circuit, and a filter capacitor, wherein... One end of the fourth switching circuit serves as the positive input terminal of the step-down circuit, and the other end of the fourth switching circuit is connected to one end of the second inductor and one end of the third unidirectional conduction circuit, respectively. The other end of the second inductor is connected to one end of the filter capacitor, and the other end of the filter capacitor is connected to the other end of the third unidirectional conduction circuit. The connection point between the third unidirectional conduction circuit and the filter capacitor serves as the negative input terminal of the step-down circuit. The two ends of the filter capacitor serve as the output ports of the step-down circuit. The control terminal of the fourth switching circuit is used to receive the drive signal; In the first mode, the fourth switching circuit is turned off; In the second mode, the fourth switching circuit is turned on; The conduction direction of the third unidirectional conduction circuit is opposite to the charging direction of the energy storage capacitor.

9. The power conversion circuit according to claim 7, characterized in that, The third switching circuit includes a fourth unidirectional conduction circuit, and the conduction direction of the fourth unidirectional conduction circuit is opposite to the charging direction of the energy storage capacitor.

10. The power conversion circuit according to any one of claims 1 to 9, characterized in that, Also includes: Controller, where The controller is connected to the first power conversion sub-circuit and the second power conversion sub-circuit respectively; The controller is used to output the drive signal.

11. A power supply system, characterized in that, include: The power supply module and the power conversion circuit according to any one of claims 1 to 10, wherein, The power supply module supplies power to the electrical load through the power conversion circuit.

12. The power supply system according to claim 11, characterized in that, The power supply module includes photovoltaic modules or energy storage batteries.

Images