Power conversion circuit and power device

Abstract

The application relates to a power conversion circuit and a power device, the power conversion circuit comprising a bridge arm circuit, an inductor circuit connected with the bridge arm circuit, and a load port connected with the inductor circuit, the power conversion circuit further comprising a detection circuit and a control circuit, the inductor circuit having different connection states, and the equivalent inductance corresponding to different connection states being different; the detection circuit is used for detecting a load connection state of the load port; the control circuit is connected with the detection circuit and the inductor circuit, and is used for switching the connection state of the inductor circuit according to the load connection state. Through the above-mentioned circuit, the equivalent inductance of the inductor circuit can be automatically adjusted according to the load connection state, the current ripple and the magnetic flux change amplitude can be reduced when the load is light, the magnetic core loss and the switching loss of the bridge arm circuit can be significantly reduced, and the standby efficiency is improved; when the load is heavy, the inductor circuit can be switched to small inductance, the current rising rate is accelerated, the instantaneous heavy current load can be effectively coped with, and the system stability is improved.

Description

Technical Field

[0001] This application belongs to the field of power electronics technology, and in particular relates to a power conversion circuit and power equipment. Background Technology

[0002] With the increasing demand for portable energy, mobile energy storage power supplies are widely used in outdoor power consumption, emergency power supply, and home backup power. One of their core functions is to convert direct current (DC) to alternating current (AC) or direct current (DC) through power conversion circuits to drive various loads. In the inverter system of traditional mobile energy storage power supplies, inductor windings are typically used as filtering and energy storage components. However, conventional designs suffer from drawbacks such as high power consumption under light loads, poor impact load capacity, and difficulty in achieving optimal performance. Summary of the Invention

[0003] The purpose of this application is to provide a power conversion circuit and power equipment, which aims to solve the problems of high power consumption under light load and poor impact load capacity of power conversion circuits in related technologies.

[0004] In a first aspect, embodiments of this application provide a power conversion circuit, the power conversion circuit including a bridge arm circuit, an inductor circuit connected to the bridge arm circuit, and a load port connected to the inductor circuit, the power conversion circuit further including a detection circuit and a control circuit; The inductor circuit has different connection states, and the equivalent inductance corresponding to the different connection states is different. The detection circuit is used to detect the status of the load connected to the load port. The control circuit is connected to the detection circuit and the inductor circuit, and the control circuit is used to switch the connection state of the inductor circuit according to the load state.

[0005] In one embodiment, the load state includes a light load state and a heavy load state; the control circuit is configured to control the inductor circuit to be in a first connection state when the load state is a light load state; the control circuit is further configured to control the inductor circuit to be in a second connection state when the load state is a heavy load state; the equivalent inductance of the inductor circuit in the first connection state is greater than the equivalent inductance of the inductor circuit in the second connection state.

[0006] In one embodiment, the inductor circuit includes a switching component and at least two inductor windings, and the control circuit is used to control the state of the switching component to switch the series-parallel connection relationship between the inductor windings of the at least two inductor windings, thereby changing the connection state and equivalent inductance of the inductor circuit.

[0007] In one embodiment, the at least two inductor windings include a first inductor winding and a second inductor winding, and the switching assembly includes a first electronic switch, a second electronic switch and a third electronic switch; The first end of the first inductor winding constitutes the first end of the inductor circuit. The first end of the first inductor winding is also connected to the first end of the first electronic switch. The second end of the first electronic switch is connected to the first end of the second inductor winding and the first end of the second electronic switch. The second end of the first inductor winding is connected to the second end of the second electronic switch and the first end of the third electronic switch. The second end of the third electronic switch is connected to the second end of the second inductor winding and constitutes the second end of the inductor circuit.

[0008] In one embodiment, the first inductor winding and the second inductor winding are wound in parallel on the same magnetic core.

[0009] In one embodiment, the at least two inductor windings are wound on the same magnetic core; or, the at least two inductor windings are wound on different magnetic cores.

[0010] In one embodiment, the detection circuit is used to detect the output current or output power of the inductor circuit; the output current or the output power is used to characterize the load status parameters connected to the load port; The control circuit is also used to: confirm that the load state is a light load state when the load state parameter is less than the corresponding parameter threshold. If the load status parameter is greater than or equal to the parameter threshold, the load status is confirmed to be a heavy load status.

[0011] In one embodiment, the inductor circuit includes an inductor structure with dynamically adjustable inductance; the control circuit is used to change the connection state of the inductor circuit by adjusting the inductor structure.

[0012] In one embodiment, the bridge arm circuit is a half-bridge circuit or a full-bridge circuit.

[0013] Secondly, embodiments of this application also provide a power device, including the power conversion circuit described above.

[0014] The beneficial effects of this application embodiment compared with related technologies are as follows: The power conversion circuit provided in this application embodiment includes a bridge arm circuit, an inductor circuit connected to the bridge arm circuit, and a load port connected to the inductor circuit. The power conversion circuit also includes a detection circuit and a control circuit. The inductor circuit has different connection states, and the equivalent inductance corresponding to different connection states is different. The detection circuit is used to detect the load port connection state. The control circuit is connected to the detection circuit and the inductor circuit, and the control circuit is used to switch the connection state of the inductor circuit according to the load state. Through the above circuit, the equivalent inductance of the inductor circuit can be automatically adjusted according to the load state. Under light load, the current ripple and magnetic flux change amplitude are reduced, the core loss and the switching loss of the bridge arm circuit are significantly reduced, and the standby efficiency is improved. Under heavy load, the equivalent inductance of the inductor circuit can be reduced, the current rise rate is accelerated, the instantaneous large current load is effectively handled, and the system stability is improved. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the power conversion circuit provided in one embodiment of this application.

[0016] Figure 2 This is a schematic diagram of the power conversion circuit provided in one embodiment of this application.

[0017] Figure 3 This is a schematic diagram of the power conversion circuit provided in one embodiment of this application.

[0018] Figure 4 This is a circuit diagram of a power conversion circuit provided in one embodiment of this application.

[0019] Figure 5 This is a circuit diagram of a power conversion circuit provided in one embodiment of this application.

[0020] Figure 6 This is a circuit diagram of a power conversion circuit provided in one embodiment of this application. Detailed Implementation

[0021] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0022] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0023] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0025] In power conversion circuits of related technologies, inductors with fixed inductance are typically used as filtering or energy storage components. However, this design has the following problems: First, high power consumption under light load. Under light load or no-load conditions, although fixing a large inductor can reduce current ripple, it will result in a smaller change in the magnetic flux density of the core and low inductor utilization. At the same time, the high-frequency switching transistor continues to work, and the switching loss accounts for a large proportion, resulting in low overall efficiency.

[0026] Secondly, it has poor ability to cope with instantaneous load surges. When connected to loads with large starting currents, such as motors and compressors, the system needs to provide a large current instantaneously. If the inductance is too large, it will limit the rate of current rise, causing the output voltage to drop, or even triggering overcurrent protection, affecting system reliability.

[0027] Third, there are trade-offs in inductor design. In order to balance efficiency under light load and dynamic response under heavy load, traditional designs often make trade-offs in the selection of inductance, which cannot achieve optimal performance.

[0028] In addition, although there are attempts to optimize efficiency through adjustable inductors or digital control in related technologies, they mostly rely on complex magnetic core structures or additional active devices, which are costly and bulky, making them difficult to apply to compact mobile energy storage devices.

[0029] Therefore, there is an urgent need for an adaptive control scheme for inductance that is simple in structure, flexible in control, efficient and reliable, in order to optimize the efficiency and dynamic performance of power conversion circuits under different load conditions.

[0030] Specifically, please refer to Figure 1This application provides an embodiment of a power conversion circuit 100 that can be applied to power equipment. The power conversion circuit 100 includes a bridge arm circuit 110, an inductor circuit 120 connected to the bridge arm circuit 110, and a load port Vout connected to the inductor circuit 120. The power equipment can be, for example, an inverter, an energy storage device, a photovoltaic inverter system, or other power supply equipment.

[0031] The power conversion circuit 100 also includes a detection circuit 130 and a control circuit 140. The inductor circuit 120 has different connection states, and the equivalent inductance corresponding to each connection state is different. The detection circuit 130 is used to detect the load state of the load connected to the load port Vout. The control circuit 140 is connected to the detection circuit 130 and the inductor circuit 120, and the control circuit 140 is used to switch the connection state of the inductor circuit 120 according to the load state.

[0032] In the technical solution of this application embodiment, the equivalent inductance of the inductor circuit 120 can be automatically adjusted according to the load state. Under light load, it reduces current ripple and magnetic flux variation amplitude, significantly reducing core loss and switching loss of bridge arm circuit 110, and improving standby efficiency. Under heavy load, it can reduce the equivalent inductance of inductor circuit 120, that is, switch inductor circuit 120 to a small inductance, accelerate the current rise rate, effectively cope with instantaneous large current load, and improve system stability.

[0033] In some embodiments, the load state includes a light load state and a heavy load state. A light load state is, for example, when the load current is less than a first percentage of the rated current output by the power conversion circuit 100, or when the load power is less than a second percentage of the rated power output by the power conversion circuit 100. A heavy load state is, for example, when the load current is greater than a first percentage of the rated current, or when the load power is greater than a second percentage of the rated power. The first and second percentages can be set according to the application scenario, for example, they can be set to 5%, 10%, 15%, 20%, etc. Additionally, a sudden large current surge with a current change rate (di / dt) greater than a preset change rate can also be considered a heavy load state.

[0034] In this embodiment, the inductor circuit 120 includes two connection states. The equivalent inductance of the inductor circuit 120 in the first connection state is greater than that in the second connection state. The control circuit 140 is used to control the inductor circuit 120 to be in the first connection state when the load state is light. Using a large inductance in the first connection state reduces current ripple and flux variation, significantly reducing core loss and switching losses of the switching transistor, thus improving standby efficiency. The control circuit 140 is also used to control the inductor circuit 120 to be in the second connection state when the load state is heavy. Using a small inductance in the second connection state accelerates the current rise rate and effectively handles the instantaneous high current demands of motor starting and compressor operation, improving system stability. Thus, high efficiency and strong dynamic response are balanced, heat loss is reduced, energy consumption is lowered, and equipment lifespan is extended.

[0035] In some embodiments, the inductor circuit 120 includes an inductor structure with dynamically adjustable inductance. The control circuit 140 is used to change the connection state of the inductor circuit 120 by adjusting the inductor structure.

[0036] Please see Figure 2 For example, the inductor circuit 120 includes an inductor coil 121. In addition to a start terminal A1 and a stop terminal An, the inductor coil 121 also has multiple intermediate terminals A2, A3, etc. Figure 2 (Taking two intermediate terminals as an example). The equivalent inductance between each intermediate terminal A2, A3, and the tail terminal An and the head terminal A1 is different. By connecting the head terminal A1 to the bridge arm circuit 110, the different intermediate terminals A2, A3, and the tail terminal An are connected to the load port Vout through different switches S2, S3, and Sn. The control circuit 140 controls the different switches S2, S3, and Sn to turn on, changing the connection state of the inductor circuit 120, thereby realizing the dynamic adjustment of the inductance of the power conversion circuit 100.

[0037] Please see Figure 3 For example, the inductor coil includes multiple inductors 122, 123 (with or without the same inductance). Figure 3 (Taking two inductors as an example). Multiple inductors are connected in series, parallel, or in parallel via multiple electronic switches K1, K2, and K3, and then connected to the bridge arm circuit 110 and the load port Vout. The control circuit 140 controls the different electronic switches to turn on, changing the connection state of the inductor circuit 120, thereby realizing the dynamic adjustment of the inductance of the power conversion circuit 100.

[0038] In some embodiments, the inductor circuit 120 includes a switching assembly and at least two inductor windings. The control circuit 140 controls the state of the switching assembly to switch the series-parallel connection relationship between the inductor windings of the at least two inductor windings, thereby changing the connection state and equivalent inductance of the inductor circuit 120.

[0039] Please see Figure 3 For example, at least two inductor windings include a first inductor winding 122 and a second inductor winding 123, and the switching assembly includes a first electronic switch K1, a second electronic switch K2 and a third electronic switch K3.

[0040] The first end of the first inductor winding 122 forms the first end of the inductor circuit 120, and the first end of the first inductor winding 122 is also connected to the first end of the first electronic switch K1. The second end of the first electronic switch K1 is connected to the first end of the second inductor winding 123 and the first end of the second electronic switch K2. The second end of the first inductor winding 122 is connected to the second end of the second electronic switch K2 and the first end of the third electronic switch K3. The second end of the third electronic switch K3 is connected to the second end of the second inductor winding 123, and forms the second end of the inductor circuit 120.

[0041] In this embodiment, the inductance of the first inductor winding 122 and the second inductor winding 123 may be the same or different. The first inductor winding 122 and the second inductor winding 123 have a defined coupling relationship or can be used independently.

[0042] When the first electronic switch K1 and the third electronic switch K3 are open, and the second electronic switch K2 is closed, the first inductor winding 122 and the second inductor winding 123 are in series. When the first electronic switch K1 and the third electronic switch K3 are closed, and the second electronic switch K2 is open, the first inductor winding 122 and the second inductor winding 123 are in parallel. When the first electronic switch K1 and the second electronic switch K2 are open, and the third electronic switch K3 is closed, the first inductor winding 122 is connected to the circuit, and the second inductor winding 123 is in an open-circuit state.

[0043] In some embodiments, the switches S1~Sn and electronic switches K1, K2, K3 may be relays or semiconductor transistors, etc.

[0044] In some embodiments, at least two inductor windings are wound on the same magnetic core, for example, the first inductor winding 122 and the second inductor winding 123 in the above example are wound in parallel on the same magnetic core.

[0045] For example, assuming that the first inductor winding 122 and the second inductor winding 123 have the same length, wire width, and other parameters, the magnetic circuit can be made consistent, and the coupling coefficient k≈1. Let the inductance values ​​of a single turn winding be respectively... The first inductor winding 122 has The first inductor winding 122 has turns, Turns. Therefore, the inductance of the first inductor winding 122 is: The inductance of the second inductor winding 123 is: .

[0046] In series mode, the inductance of inductor circuit 120 is: .

[0047] In parallel mode, the inductance of inductor circuit 120 is: .

[0048] Under light load conditions, inductor circuit 120 operates in series, and the reduction in current ripple is: .

[0049] in, D This refers to the duty cycle. The operating frequency of the power switching circuit. This is the input voltage of the power switching circuit. This is the output voltage of the power switching circuit. It can be seen that as the amplitude of the magnetic flux change decreases, the core loss (including hysteresis loss) increases. and eddy current loss Significant decrease: .

[0050] in, The maximum magnetic flux density; This is the hysteresis loss coefficient. This is the Steinmetz coefficient. This is the eddy current loss coefficient. The magnetization frequency, i.e. .

[0051] Under heavy load conditions, the inductor circuit 120 switches to parallel mode to reduce the inductance.

[0052] The rate of change of current (di / dt) is improved to meet the requirements of transient high current: , where V is the voltage of inductor circuit 120.

[0053] At the same time, if the inductor current drops to half, the copper loss will be: It has decreased to one-quarter of its original value.

[0054] Where R is the impedance of inductor circuit 120.

[0055] In some embodiments, at least two inductor windings are wound on different magnetic cores. For example, in the example above, the first inductor winding 122 and the second inductor winding 123 are wound on different magnetic cores. The difference between this and winding the first inductor winding 122 and the second inductor winding 123 in parallel on the same magnetic core is that: In series mode, the inductance of inductor circuit 120 is: .

[0056] In parallel mode, the inductance of inductor circuit 120 is: .

[0057] Wherein, L1 is the inductance of the first inductor winding 122, and L2 is the inductance of the second inductor winding 123. The changes in different parameters under light load and heavy load conditions can be calculated with reference to the above embodiments, and will not be repeated here.

[0058] In some embodiments, the detection circuit 130 is used to detect the output current or output power of the inductor circuit 120; the output current or output power is used to characterize the load state parameters connected to the load port Vout. The control circuit 140 is also used to: If the load status parameter is less than the corresponding parameter threshold, the load status is confirmed as light load.

[0059] If the load status parameter is greater than or equal to the parameter threshold, the load status is confirmed as overloaded.

[0060] In some embodiments, the control circuit 140 includes a PWM signal generation unit 141 and a driving unit 142.

[0061] The PWM signal generation unit 141 is connected to the detection circuit 130 and is used to generate a corresponding PWM signal according to the load state parameters. The drive unit 142 is connected to the PWM signal generation unit 141 and the inductor circuit 120 and is used to switch the connection state of the inductor circuit 120 according to the PWM signal.

[0062] If the electronic switch in inductor circuit 120 is a relay, then drive unit 142 is a relay drive circuit or chip. If the electronic switch in inductor circuit 120 is a semiconductor transistor, then drive unit 142 is a transistor drive circuit or chip. PWM signal generation unit 141 is, for example, a microprocessor.

[0063] In some embodiments, the detection circuit 130 includes a current detection circuit for detecting the load current. In some embodiments, the detection circuit 130 includes a current detection circuit and a voltage detection circuit for detecting the load current and load voltage, respectively, thereby obtaining the load power.

[0064] Please see Figures 4 to 6In some embodiments, the bridge arm circuit 110 can be a half-bridge circuit or a full-bridge circuit, such as a single-phase half-bridge circuit, a single-phase full-bridge circuit, or a three-phase full-bridge circuit.

[0065] Please see Figure 4 and Figure 5 In some embodiments, the bridge arm circuit 110 is a single-phase half-bridge circuit or a single-phase full-bridge circuit with two bridge arm midpoints. The first end of the inductor circuit 120 is connected to one of the bridge arm midpoints, and the second end of the inductor circuit 120 serves as the output terminal.

[0066] Please see Figure 6 In some embodiments, the bridge arm circuit 110 is a three-phase full-bridge circuit with three bridge arm midpoints. There are three inductor circuits 120. The first end of the three inductor circuits 120 is connected to one bridge arm midpoint in a one-to-one correspondence. The second end of the three inductor circuits 120 is respectively connected to the three-phase terminals A, B, and C of the output port Vout.

[0067] Please see Figure 4 and Figure 5 In some embodiments, the power conversion circuit 100 is a single-phase half-bridge circuit or a single-phase full-bridge circuit, and also includes an output capacitor C1, which is connected between the positive and negative terminals of the output terminal.

[0068] The power conversion circuit 100 is a three-phase circuit and also includes three output capacitors C. 11 C 12 C 13 Three output capacitors C 11 C 12 C 13 Connect the three-phase terminals A, B, C and N of the output port Vout respectively.

[0069] In other embodiments, the power conversion circuit may also be a buck circuit including a half-bridge circuit, a boost circuit including a half-bridge circuit, or a buck-boost circuit including a full-bridge circuit.

[0070] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0071] Those skilled in the art will 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, or a combination of computer software and electronic hardware. 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.

[0072] In the embodiments provided in this application, it should be understood that the disclosed devices / electronic devices and methods can be implemented in other ways. For example, the device / electronic device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0073] 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 units can be selected to achieve the purpose of this embodiment according to actual needs.

[0074] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A power conversion circuit, characterized in that, The power conversion circuit includes a bridge arm circuit, an inductor circuit connected to the bridge arm circuit, and a load port connected to the inductor circuit. The power conversion circuit also includes a detection circuit and a control circuit. The inductor circuit has different connection states, and the equivalent inductance corresponding to the different connection states is different. The detection circuit is used to detect the status of the load connected to the load port. The control circuit is connected to the detection circuit and the inductor circuit, and the control circuit is used to switch the connection state of the inductor circuit according to the load state.

2. The power conversion circuit as described in claim 1, characterized in that, The load states include a light load state and a heavy load state; the control circuit is used to control the inductor circuit to be in a first connection state when the load state is a light load state; the control circuit is also used to control the inductor circuit to be in a second connection state when the load state is a heavy load state; the equivalent inductance of the inductor circuit in the first connection state is greater than the equivalent inductance of the inductor circuit in the second connection state.

3. The power conversion circuit as described in claim 1 or 2, characterized in that, The inductor circuit includes a switching assembly and at least two inductor windings. The control circuit is used to control the state of the switching assembly to switch the series-parallel connection relationship between the inductor windings of the at least two inductor windings, thereby changing the connection state and equivalent inductance of the inductor circuit.

4. The power conversion circuit as described in claim 3, characterized in that, The at least two inductor windings include a first inductor winding and a second inductor winding, and the switching assembly includes a first electronic switch, a second electronic switch and a third electronic switch; The first end of the first inductor winding constitutes the first end of the inductor circuit. The first end of the first inductor winding is also connected to the first end of the first electronic switch. The second end of the first electronic switch is connected to the first end of the second inductor winding and the first end of the second electronic switch. The second end of the first inductor winding is connected to the second end of the second electronic switch and the first end of the third electronic switch. The second end of the third electronic switch is connected to the second end of the second inductor winding and constitutes the second end of the inductor circuit.

5. The power conversion circuit as described in claim 4, characterized in that, The first inductor winding and the second inductor winding are wound in parallel on the same magnetic core.

6. The power conversion circuit as described in claim 3, characterized in that, The at least two inductor windings are wound on the same magnetic core; or, the at least two inductor windings are wound on different magnetic cores.

7. The power conversion circuit according to any one of claims 2 to 6, characterized in that, The detection circuit is used to detect the output current or output power of the inductor circuit; the output current or the output power is used to characterize the load status parameters connected to the load port. The control circuit is also used to: confirm that the load state is a light load state when the load state parameter is less than the corresponding parameter threshold. If the load status parameter is greater than or equal to the parameter threshold, the load status is confirmed to be a heavy load status.

8. The power conversion circuit as described in claim 1, characterized in that, The inductor circuit includes an inductor structure with dynamically adjustable inductance; the control circuit is used to change the connection state of the inductor circuit by adjusting the inductor structure.

9. The power conversion circuit according to any one of claims 1 to 8, characterized in that, The bridge arm circuit is a half-bridge circuit or a full-bridge circuit.

10. An electrical device, characterized in that, Includes the power conversion circuit as described in any one of claims 1 to 9.

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