Single-phase DC-AC converter circuit and energy storage converter equipment

Abstract

This application relates to a single-phase DC-AC converter circuit and an energy storage converter device. The AC side of the single-phase DC-AC converter circuit includes an AC side winding, a rectifier circuit, and a switching circuit. A first terminal of the rectifier circuit is connected to the AC side winding, and a second terminal of the rectifier circuit is connected to the first terminal of the switching circuit. The rectifier circuit is used to convert a first AC current into a target pulsating current. The second terminal of the switching circuit is connected to the power grid, and the switching circuit is used to switch the target pulsating current into a second AC current. The control logic of the above-described single-phase DC-AC converter circuit is relatively simple and easy to implement.

Description

Technical Field

[0001] This application relates to the field of new energy technology, and in particular to a single-phase DC-AC converter circuit and an energy storage converter device. Background Technology

[0002] In related technologies, the AC measurement circuit of a single-phase DC-AC converter uses a half-bridge circuit composed of bidirectional switching transistors to convert the high-frequency AC power output from the transformer into AC power suitable for input to the power grid. However, the control logic of the bidirectional switching transistors is relatively complex. Utility Model Content

[0003] Therefore, it is necessary to provide a single-phase DC-AC converter circuit and energy storage converter device that can reduce the complexity of control logic to address the above-mentioned technical problems.

[0004] In one aspect, a single-phase DC-AC converter circuit is provided. The AC side of the single-phase DC-AC converter circuit includes an AC side winding, a rectifier circuit, and a switching circuit;

[0005] The first end of the rectifier circuit is connected to the AC side winding, and the second end of the rectifier circuit is connected to the first end of the flip circuit. The rectifier circuit is used to convert the first AC current into the target pulsating current.

[0006] The second end of the flip circuit is used to connect to the power grid, and the flip circuit is used to flip the target pulsating current into a second alternating current.

[0007] In one embodiment, the rectifier circuit includes a bridge rectifier circuit and a filter capacitor, wherein,

[0008] The first terminal of the bridge rectifier circuit is connected to the AC side winding, and the second terminal of the bridge rectifier circuit is connected in parallel with the filter capacitor. The bridge rectifier circuit is used to convert the first AC current into an initial pulsating current, and the filter capacitor is used to filter the initial pulsating current to obtain the target pulsating current.

[0009] The first terminal of the flip circuit is connected in parallel with the filter capacitor.

[0010] In one embodiment, the capacitance value of the filter capacitor ranges from 1 microfarad to 10 microfarads.

[0011] In one embodiment, the filter capacitor is a thin-film capacitor.

[0012] In one embodiment, the bridge rectifier circuit includes: a half-bridge rectifier circuit, a first resonant capacitor, and a second resonant capacitor, wherein...

[0013] The first terminal of the half-bridge rectifier circuit is connected to the AC side winding, and the second terminal of the half-bridge rectifier circuit is connected in parallel with the filter capacitor. The half-bridge rectifier circuit includes a first switching transistor and a second switching transistor, and the first switching transistor and the second switching transistor have the same conduction direction.

[0014] The first resonant capacitor corresponds to the first switching transistor, and the second resonant capacitor corresponds to the second switching transistor.

[0015] In one embodiment, the bridge rectifier circuit includes: a third resonant capacitor and an H-bridge rectifier circuit;

[0016] The first terminal of the H-bridge rectifier circuit is connected to the AC side winding through the third resonant capacitor. The second terminal of the H-bridge rectifier circuit is connected in parallel with the filter capacitor. The H-bridge rectifier circuit includes a third, fourth, fifth, and sixth switch transistor, and the third, fourth, fifth, and sixth switch transistors have the same conduction direction.

[0017] In one embodiment, the switching circuit includes an H-bridge switching circuit, wherein,

[0018] The first arm of the H-bridge flip circuit includes the seventh and eighth switching transistors, and the second arm of the H-bridge flip circuit includes the ninth and tenth switching transistors.

[0019] In one embodiment, the AC side of the single-phase DC-AC converter circuit further includes a filter circuit;

[0020] The second terminal of the flip circuit is connected to the first terminal of the filter circuit.

[0021] The second end of the filter circuit is used to connect to the power grid.

[0022] In one embodiment, the DC side of the single-phase DC-AC converter circuit includes a DC side capacitor, multiple inverter H-bridge circuits, and multiple DC side windings, and the number of AC side windings is also multiple.

[0023] Multiple inverter H-bridge circuits are connected in parallel across the DC-side capacitor;

[0024] Multiple inverter H-bridge circuits are connected one-to-one with multiple DC-side windings;

[0025] Multiple AC side windings are connected in series to form a rectifier circuit.

[0026] Secondly, this application provides an energy storage converter device, including the single-phase DC-AC converter circuit provided in the first aspect.

[0027] The single-phase DC-AC converter circuit and energy storage converter device provided in the above embodiments include an AC-side winding, a rectifier circuit, and a switching circuit on the AC side of the single-phase DC-AC converter circuit. The first end of the rectifier circuit is connected to the AC-side winding, and the second end of the rectifier circuit is connected to the first end of the switching circuit. The rectifier circuit is used to convert a first AC current into a target pulsating current. The second end of the switching circuit is connected to the power grid, and the switching circuit is used to switch the target pulsating current into a second AC current. In this way, the above-mentioned single-phase DC-AC converter circuit avoids the problem in related technologies where a half-bridge circuit composed of bidirectional switching transistors is used to directly convert the high-frequency AC output from the AC-side winding into a sinusoidal AC current, resulting in complex AC-side control logic. Using the above-mentioned single-phase DC-AC converter circuit, the first AC current output from the AC-side winding is first converted into a target pulsating current by the rectifier circuit, and then the target pulsating current is switched into a second AC current consistent with the AC waveform of the power grid by the switching circuit. The switching transistors included in the rectifier circuit can be switching transistors with the same conduction direction. Therefore, the control logic of the single-phase DC-AC converter circuit provided in this application is relatively simple and easy to implement. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a block diagram of a single-phase DC-AC converter circuit in one embodiment;

[0030] Figure 2 The waveform of the target pulsating current in one embodiment is shown.

[0031] Figure 3 The waveform of the target pulsating current is shown in another embodiment;

[0032] Figure 4 This is a block diagram of a single-phase DC-AC converter circuit in another embodiment;

[0033] Figure 5 This is a schematic diagram of the circuit topology of a single-phase DC-AC converter circuit in one embodiment;

[0034] Figure 6 This is a schematic diagram of the circuit topology of a single-phase DC-AC converter circuit in another embodiment.

[0035] Figure label:

[0036] 100. AC side winding; 200. Rectifier circuit; 210. Bridge rectifier circuit; 300. Flip circuit; 400. DC side winding; 500. Inverter H-bridge circuit; 600. Filter circuit. Detailed Implementation

[0037] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0039] It is understood that the terms "first," "second," etc., used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0040] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0041] It is understood that the term "based on" as used in this application is used to describe one or more factors that influence the determination, but does not exclude other factors that may influence the determination. For example, the phrase "determine A based on B" means that the determination of A can be based entirely or at least partially on factor B. That is, B is a factor that influences the determination of A, but does not exclude the fact that the determination of A is also based on C.

[0042] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0043] In one exemplary embodiment, please refer to Figure 1 The AC side of the provided single-phase DC-AC converter circuit includes an AC side winding 100, a rectifier circuit 200, and a switching circuit 300.

[0044] The first end of the rectifier circuit 200 is connected to the AC side winding 100, and the second end of the rectifier circuit 200 is connected to the first end of the flip circuit 300. The rectifier circuit 200 is used to convert the first AC current into the target pulsating current.

[0045] The first AC current is a high-frequency AC pulse current output by the AC side winding 100. The frequency of the target pulsating current is twice the power grid frequency. The amplitude of the target pulsating current is determined based on the amplitude of the power grid AC current. The waveform of the target pulsating current is as follows: Figure 2 or Figure 3 The waveform of the steamed bun shown is shown.

[0046] In this embodiment, the rectifier circuit 200 converts the first AC current into a pulsating current with constant polarity. Therefore, the switching transistors included in the rectifier circuit 200 can be switching transistors with the same conduction direction. Under some special operating conditions (such as wave blocking), the current on the inductor can be discharged to the AC bus instead of being loaded onto the two ends of the switching transistor. There is no need to perform special control for special operating conditions, which makes the control logic of the rectifier circuit 200 simple.

[0047] For example, if the power grid frequency is 50Hz or 60Hz, the corresponding target pulsating current power is 100Hz or 120Hz.

[0048] The second terminal of the switching circuit 300 is connected to the power grid to switch the target current into a second AC current. The frequency of the second AC current is equal to the power grid frequency, and the amplitude of the second AC current is determined based on the amplitude of the power grid AC current.

[0049] In this embodiment, the switching circuit 300 converts the target pulsating current of the steamed bun waveform into a sinusoidal form of the grid current. The switching frequency of the switching transistor in the switching circuit 300 is twice the power frequency, reducing the switching losses of the switching circuit 300. Therefore, the switching circuit 300 can use a low-frequency switching transistor, reducing hardware costs. For example, the switching frequency of the switching transistor in the switching circuit 300 is 100Hz or 120Hz.

[0050] The single-phase DC-AC converter circuit provided in the above embodiment avoids the problem in related technologies where a half-bridge circuit composed of bidirectional switching transistors is used to directly convert the high-frequency AC output from the AC side winding into a sinusoidal AC current, resulting in complex AC side control logic. The single-phase DC-AC converter circuit provided in this embodiment first converts the first AC current output from the AC side winding 100 into a target pulsating current through the rectifier circuit 200, and then flips the target pulsating current into a second AC current consistent with the AC waveform of the power grid through the flip circuit 300. The switching transistors included in the rectifier circuit 200 can be switching transistors with the same conduction direction. Therefore, the control logic of the single-phase DC-AC converter circuit in this embodiment is relatively simple and easy to implement.

[0051] In the accompanying drawings of the embodiments of this application, DC represents the DC power supply and AC represents the power grid.

[0052] Please refer to Figure 1 The DC side of the single-phase DC-AC converter circuit provided in this embodiment includes a DC side winding 400, an inverter H-bridge circuit 500, and a DC side capacitor C1. The DC side capacitor C1 is connected to the DC bus. The first end of the inverter H-bridge circuit 500 is connected in parallel with the DC side capacitor C1, and the second end of the inverter H-bridge circuit 500 is connected to the DC side winding 400. The DC side winding 400 and the AC side winding 100 are the two ends of the transformer, respectively.

[0053] The inverter H-bridge circuit 500 is used to convert the DC power output from the DC power supply into high-frequency AC power, which is then transmitted to the AC side winding 100 through the DC side winding 400.

[0054] In an exemplary embodiment, the rectifier circuit 200 includes a bridge rectifier circuit 210 and a filter capacitor C2. The first terminal of the bridge rectifier circuit 210 is connected to the AC side winding 100, and the second terminal of the bridge rectifier circuit 210 is connected in parallel with the filter capacitor C2. The bridge rectifier circuit 210 is used to convert the first AC current into an initial pulsating current, and the filter capacitor C2 is used to filter the initial pulsating current to obtain the target pulsating current. The first terminal of the flip circuit 300 is connected in parallel with the filter capacitor C2.

[0055] Among them, the filter capacitor C2 filters out the high-frequency ripples in the initial pulsating current and outputs the target pulsating current with a smooth waveform.

[0056] In this embodiment, the filter capacitor C2 only needs to filter out the high-frequency ripples in the initial pulsating current, and does not need to filter the initial pulsating current into a DC form with a constant amplitude. Therefore, the filter capacitor C2 can be a capacitor with a small capacitance value.

[0057] In one possible implementation, the capacitance value of the filter capacitor C2 ranges from 1uF (microfarads) to 10uF.

[0058] For example, the specific capacitance value of the filter capacitor C2 can be determined based on the operating power of the single-phase DC-AC converter circuit and the switching frequency of the bridge rectifier circuit. For example, the switching frequency of the bridge rectifier circuit ranges from 80kHz to 200kHz.

[0059] In one possible implementation, the filter capacitor C2 is a film capacitor. A film capacitor is a capacitor made with a plastic film (such as polyester or polypropylene) as the dielectric and metallized or foil electrodes, and has the characteristics of high reliability and low loss. In the single-phase DC-AC converter circuit provided in this embodiment, the filter capacitor C2 is implemented using a film capacitor, which reduces the hardware cost of the filter capacitor C2 and improves circuit reliability and product life.

[0060] In one exemplary embodiment, based on Figure 4 The embodiment shown provides a single-phase DC-AC converter circuit; please refer to... Figure 5 The bridge rectifier circuit 210 includes a half-bridge rectifier circuit, a first resonant capacitor C3, and a second resonant capacitor C4. Please refer to [reference needed]. Figure 5 The first terminal of the half-bridge rectifier circuit is connected to the AC side winding 100, and the second terminal of the half-bridge rectifier circuit is connected in parallel with the filter capacitor C2. The half-bridge rectifier circuit includes a first switching transistor T. Z1 Second switch T Z2 The first switching transistor T Z1 Second switch T Z2 The conduction directions are the same; the first resonant capacitor C3 and the first switching transistor T Z1 Correspondingly, the second resonant capacitor C4 and the second switch T Z2 correspond.

[0061] Among them, the first switching transistor T Z1 The source of the transistor is connected to the first end of the AC side winding 100, and the first switching transistor T... Z1 The drain of the second resonant capacitor C4 is connected to the first terminal of the first resonant capacitor C3, and the second terminal of the first resonant capacitor C3 is connected to the second terminal of the AC side winding 100. The first terminal of the second resonant capacitor C4 is connected to the second terminal of the AC side winding 100, and the second terminal of the second resonant capacitor C4 is connected to the second switching transistor T. Z2 The source connection, the second switch T Z2 The drain of the first transistor is connected to the first end of the AC side winding 100; the first switching transistor T Z1 The gate and the second switch T Z2 The gates of each are connected to a switch drive circuit (not shown in the figure). The half-bridge rectifier circuit is used to convert the first AC current output from the AC side winding 100 into an initial pulsating current.

[0062] It should be noted that, Figure 5In the single-phase DC-AC converter circuit example shown, the DC side includes multiple inverter H-bridge circuits 500 and multiple DC side windings 400. Correspondingly, there are multiple AC side windings 100. In this example, for the rectifier circuit, the first and second ends of the AC side windings 100 are the first and second ends of the AC side windings 100 connected in series as the whole AC side winding.

[0063] The first resonant capacitor C3 and the leakage inductance of the AC side winding 100 form a resonant cavity, which is used to power the first switching transistor T. Z1 To provide resonant current for soft-switching control, the second resonant capacitor C4 and the leakage inductance of the AC side winding 100 form another resonant cavity, which is used to supply the second switching transistor T. Z2 Soft-switching control provides resonant current to reduce switching losses in the half-bridge rectifier circuit.

[0064] In one possible implementation, the first resonant capacitor C3 and the second resonant capacitor C4 can be implemented using multiple capacitors with small capacitance values ​​connected in parallel. For example, the first resonant capacitor C3 comprises eight 22nF ceramic capacitors connected in parallel; the second resonant capacitor C4 comprises eight 22nF ceramic capacitors connected in parallel. In this implementation, using multiple capacitors with small capacitance values ​​in parallel reduces the equivalent series resistance and inductance, improves high-frequency characteristics, suppresses high-frequency noise, and allows for the distributed arrangement of multiple small capacitors during circuit layout, avoiding localized overheating.

[0065] In one possible implementation of this embodiment, the bridge rectifier circuit includes a resonant inductor, which, together with the leakage inductance of the AC side winding 100, the first resonant capacitor C3, and the second resonant capacitor C4, forms the resonant cavity in the bridge rectifier circuit.

[0066] In one exemplary embodiment, based on Figure 4 The embodiment shown provides a single-phase DC-AC converter circuit, see [link to example]. Figure 6 The bridge rectifier circuit includes a third resonant capacitor C5 and an H-bridge rectifier circuit. The first terminal of the H-bridge rectifier circuit is connected to the AC winding via the third resonant capacitor C5, and the second terminal of the H-bridge rectifier circuit is connected in parallel with the filter capacitor C2. Please refer to [reference needed]. Figure 6 The H-bridge rectifier circuit includes a third switching transistor T. Z3 Fourth switch T Z4 Fifth switch transistor T Z5 and the sixth switch T Z6 Third switch T Z3 Fourth switch T Z4 Fifth switch transistor T Z5 and the sixth switch T Z6The conduction directions are the same. The H-bridge rectifier circuit is used to convert the first AC current into an initial pulsating current.

[0067] For example, please refer to Figure 6 The first arm of the H-bridge rectifier circuit includes the third switching transistor T. Z3 and the fourth switch T Z4 The midpoint of the first arm of the H-bridge rectifier circuit is connected to the first end of the AC side winding 100. The second arm of the H-bridge rectifier circuit includes the fifth switching transistor T. Z5 and the sixth switch T Z6 The midpoint of the second bridge arm of the H-bridge rectifier circuit is connected to the second end of the third resonant capacitor C5, and the first end of the third resonant capacitor C5 is connected to the second end of the AC side winding 100.

[0068] It should be noted that, Figure 6 In the single-phase DC-AC converter circuit example shown, the DC side includes multiple inverter H-bridge circuits 500 and multiple DC side windings 400. Correspondingly, there are multiple AC side windings 100. In this example, for the rectifier circuit, the first and second ends of the AC side windings 100 are the first and second ends of the AC side windings 100 connected in series as the whole AC side winding.

[0069] In other examples of this embodiment, the third resonant capacitor C5 can be located between the midpoint of the first arm of the H-bridge rectifier circuit and the first end of the AC winding.

[0070] The third resonant capacitor C5 and the leakage inductance of the AC side winding 100 form a resonant cavity. The switching transistors in the H-bridge rectifier circuit achieve soft switching control to provide resonant current and reduce the switching losses of the H-bridge rectifier circuit.

[0071] In this embodiment, the rectifier circuit 200 is implemented based on the H-bridge rectifier circuit, and a resonant cavity is set to provide the resonant current required for soft switching. A resonant capacitor with a small capacitance value can be used.

[0072] In one possible implementation, the third resonant capacitor C5 can be implemented using multiple capacitors with small capacitance values ​​connected in parallel. For example, the third resonant capacitor C5 comprises seven 22nF ceramic capacitors connected in parallel.

[0073] In one possible implementation of this embodiment, the bridge rectifier circuit includes a resonant inductor, which, together with the leakage inductance of the AC side winding 100 and the third resonant capacitor C5, forms the resonant cavity in the bridge rectifier circuit.

[0074] In one exemplary embodiment, please refer to Figure 5 and Figure 6The switching circuit 300 includes an H-bridge switching circuit. The first arm of the H-bridge switching circuit includes a seventh switching transistor T. U1 and the eighth switch T U2 The second arm of the H-bridge flip circuit includes the ninth switch transistor T. U3 and the tenth switch T U4 The H-bridge flip-flop circuit is used to flip a target pulsating current in the form of a wavy wave into a second AC current in the form of a sine wave.

[0075] Please refer to Figure 6 The seventh switch transistor T U1 The source, the ninth switch T U3 The source, the eighth switch T U2 The drain and the tenth switch T U4 The drain of the bridge is used as the first terminal of the H-bridge switching circuit, and the midpoint of the two bridge arms is used as the second terminal of the H-bridge switching circuit.

[0076] In one exemplary embodiment, please continue to refer to Figure 5 and Figure 6 The AC side of the single-phase DC-AC converter circuit also includes a filter circuit 600. The second terminal of the switching circuit 300 is connected to the first terminal of the filter circuit 600, and the second terminal of the filter circuit 600 is used to connect to the power grid. The filter circuit 600 is used to reduce high-frequency common-mode interference between the single-phase DC-AC converter circuit and the power grid.

[0077] In one possible implementation, the filter circuit 600 includes a common-mode inductor.

[0078] In an exemplary embodiment, the DC side of the provided single-phase DC-AC converter circuit includes a DC-side capacitor C1, multiple inverter H-bridge circuits 500, and multiple DC-side windings 400, and the AC-side windings 100 are multiple in number; wherein, the multiple inverter H-bridge circuits 500 are connected in parallel to the two ends of the DC-side capacitor C1; the multiple inverter H-bridge circuits 500 are connected one-to-one with the multiple DC-side windings 400, and the multiple AC-side windings 100 are connected in series to the rectifier circuit.

[0079] Please refer to Figure 5 and Figure 6 For ease of demonstration, this embodiment uses a single-phase DC-AC converter circuit with two inverter H-bridge circuits 500 and two DC-side windings 400 on the DC side, and two AC-side windings 100 on the AC side as an example to illustrate the circuit structure of the single-phase DC-AC converter circuit provided. In this example, the DC-side capacitor is capacitor C1; the first arm of the first inverter H-bridge circuit 500 includes a switching transistor T. 11 and switching transistor T 12 The second arm of the first inverter H-bridge circuit 500 includes the switching transistor T. 13and switching transistor T 14 Switch T 11 and switching transistor T 12 The midpoint and the switching transistor T 13 and switching transistor T 14 The midpoint serves as the interface of the first inverter H-bridge circuit 500, connecting to the DC-side winding 400 in transformer TS1; the first arm of the second inverter H-bridge circuit 500 includes the switching transistor T. 21 and switching transistor T 22 The second bridge arm of the second inverter H-bridge circuit 500 includes the switching transistor T. 23 and switching transistor T 24 Switch T 21 and switching transistor T 22 The midpoint and the switching transistor T 23 and switching transistor T 24 The midpoint serves as the interface for the second inverter H-bridge circuit 500, connecting to the DC side winding 400 in transformer TS2; the two AC side windings 100 are connected in series to the first end of rectifier circuit 200.

[0080] In this embodiment, the DC side of the single-phase DC-AC converter circuit includes multiple parallel inverter H-bridge circuits 500. Thus, when the current value corresponding to the DC side of the single-phase DC-AC converter circuit is large, the current is distributed by multiple inverter H-bridge circuits 500, so that each inverter H-bridge circuit 500 can carry a smaller current. This reduces the complexity of loss control and thermal design of the switching transistors in the inverter H-bridge circuit 500, and is suitable for various power conversion scenarios, including low-voltage and high-current DC sides.

[0081] In one exemplary embodiment, please refer to Figure 5 and Figure 6 The provided single-phase DC-AC converter circuit includes a DC-side capacitor C1, multiple inverter H-bridge circuits 500, and multiple DC-side windings 400 on the DC side, and multiple AC-side windings 100, a rectifier circuit 200, an H-bridge switching circuit, and a filter circuit 600 on the AC side. Multiple inverter H-bridge circuits 500 are connected in parallel across the DC-side capacitor C1. Each inverter H-bridge circuit 500 is connected to a corresponding DC-side winding 400. Multiple AC-side windings 100 are connected in series to the first terminal of the rectifier circuit 200. The second terminal of the rectifier circuit 200 is connected to the first terminal of the switching circuit 300, and the second terminal of the switching circuit 300 is connected to the first terminal of the filter circuit 600. The second terminal of the filter circuit 600 is connected to the power grid.

[0082] The rectifier circuit 200 includes a bridge rectifier circuit and a filter capacitor C2. The second terminal of the bridge rectifier circuit is connected in parallel with the filter capacitor C2, and the first terminal of the H-bridge switching circuit is connected in parallel with the filter capacitor C2. The bridge rectifier circuit is used to convert the first AC circuit into an initial pulsating current, the filter capacitor C2 is used to filter the initial pulsating current to obtain the target pulsating current, and the H-bridge switching circuit is used to switch the target pulsating current into a second AC current.

[0083] Among them, the capacitance of the filter capacitor C2 is less than or equal to 10nF, and the filter capacitor C2 is a film capacitor.

[0084] Optionally, the bridge rectifier circuit includes a half-bridge rectifier circuit, a first resonant capacitor C3, and a second resonant capacitor C4. The first terminal of the half-bridge rectifier circuit is connected to the AC side winding 100, and the second terminal of the half-bridge rectifier circuit is connected in parallel with the filter capacitor C2. The half-bridge rectifier circuit includes a first switch and a second switch, and the first switch and the second switch have the same conduction direction. The first resonant capacitor C3 corresponds to the first switch, and the second resonant capacitor C4 corresponds to the second switch.

[0085] Optionally, the bridge rectifier circuit includes: a third resonant capacitor C5 and an H-bridge rectifier circuit; the first terminal of the H-bridge rectifier circuit is connected to the AC side winding through the third resonant capacitor C5, the second terminal of the H-bridge rectifier circuit is connected in parallel with the filter capacitor C2, and the H-bridge rectifier circuit includes a third switch, a fourth switch, a fifth switch, and a sixth switch, all of which have the same conduction direction.

[0086] The first arm of the H-bridge flip circuit includes the seventh and eighth switching transistors, and the second arm of the H-bridge flip circuit includes the ninth and tenth switching transistors.

[0087] In this embodiment, the switching transistor on the DC side of the single-phase DC-AC converter circuit can be a switching transistor with a withstand voltage of 40V, 80V, or 100V, such as Si MOS (Silicon Metal-Oxide-Semiconductor), GaN (Gallium Nitride), or SiCMOS (Silicon Carbide Metal-Oxide-Semiconductor). The switching transistor on the AC side of the single-phase DC-AC converter circuit can be a switching transistor with a withstand voltage of 600V or 650V, such as Si MOS, GaN, SiCMOS, or IGBT (Insulated Gate Bipolar Transistor).

[0088] In one exemplary embodiment, an energy storage converter is provided, including the single-phase DC-AC converter circuit provided in the above embodiment.

[0089] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0090] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A single phase DC-AC conversion circuit, characterized by, The AC side of the single-phase DC-AC converter circuit includes an AC side winding, a rectifier circuit, and a switching circuit. The first end of the rectifier circuit is connected to the AC side winding, and the second end of the rectifier circuit is connected to the first end of the flip circuit. The rectifier circuit is used to convert the first AC current into the target pulsating current. The second end of the flip circuit is used to connect to the power grid, and the flip circuit is used to flip the target pulsating current into a second alternating current.

2. The single-phase DC-AC conversion circuit according to claim 1, characterized in that, The rectifier circuit includes a bridge rectifier circuit and a filter capacitor, wherein... The first terminal of the bridge rectifier circuit is connected to the AC side winding, and the second terminal of the bridge rectifier circuit is connected in parallel with the filter capacitor. The bridge rectifier circuit is used to convert the first AC current into an initial pulsating current, and the filter capacitor is used to filter the initial pulsating current to obtain the target pulsating current. The first terminal of the flip circuit is connected in parallel with the filter capacitor.

3. The single-phase DC-AC converter circuit according to claim 2, characterized in that, The capacitance value of the filter capacitor ranges from 1 microfarad to 10 microfarads.

4. The single-phase DC-AC converter circuit according to claim 2, characterized in that, The filter capacitor is a thin-film capacitor.

5. The single-phase DC-AC converter circuit according to claim 2, characterized in that, The bridge rectifier circuit includes: a half-bridge rectifier circuit, a first resonant capacitor, and a second resonant capacitor, wherein... The first end of the half-bridge rectifier circuit is connected to the AC side winding, and the second end of the half-bridge rectifier circuit is connected in parallel with the filter capacitor. The half-bridge rectifier circuit includes a first switch and a second switch, and the first switch and the second switch have the same conduction direction. The first resonant capacitor corresponds to the first switching transistor, and the second resonant capacitor corresponds to the second switching transistor.

6. The single-phase DC-AC converter circuit according to claim 2, characterized in that, The bridge rectifier circuit includes: a third resonant capacitor and an H-bridge rectifier circuit; The first terminal of the H-bridge rectifier circuit is connected to the AC side winding through the third resonant capacitor. The second terminal of the H-bridge rectifier circuit is connected in parallel with the filter capacitor. The H-bridge rectifier circuit includes a third switch, a fourth switch, a fifth switch, and a sixth switch. The third switch, the fourth switch, the fifth switch, and the sixth switch have the same conduction direction.

7. The single-phase DC-AC converter circuit according to claim 1, characterized in that, The flip circuit includes: an H-bridge flip circuit, wherein... The first arm of the H-bridge flip circuit includes a seventh switch and an eighth switch, and the second arm of the H-bridge flip circuit includes a ninth switch and a tenth switch.

8. The single-phase DC-AC converter circuit according to claim 1, characterized in that, The AC side of the single-phase DC-AC converter circuit also includes a filter circuit; The second terminal of the flip circuit is connected to the first terminal of the filter circuit; The second end of the filter circuit is used to connect to the power grid.

9. The single-phase DC-AC converter circuit according to claim 1, characterized in that, The DC side of the single-phase DC-AC converter circuit includes a DC side capacitor, multiple inverter H-bridge circuits, and multiple DC side windings, and the number of AC side windings is also multiple. The plurality of inverter H-bridge circuits are connected in parallel to the two ends of the DC-side capacitor; The plurality of inverter H-bridge circuits are connected one-to-one with the plurality of DC-side windings; Multiple AC-side windings are connected in series to the rectifier circuit.

10. An energy storage converter, characterized in that, The energy storage converter includes a single-phase DC-AC converter circuit as described in any one of claims 1-9.

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