Cascaded energy storage power module and high-power cascaded energy storage device

Abstract

A cascaded energy storage power module and a high-power cascaded energy storage device, the cascaded energy storage power module comprising: an H-bridge converter having a positive output end and a negative output end, the H-bridge converter being used for converting an alternating current into a direct current and outputting the direct current through the positive output end and the negative output end; one end of the first capacitor is connected with the positive output end; the positive electrode of the battery pack is connected with the other end of the first capacitor, and the negative electrode is connected with the negative output end; the first inductor is connected with the first capacitor in parallel; the first capacitor and the first inductor form a parallel resonance circuit which is used for preventing the frequency doubling current from flowing to the battery pack; and the second capacitor is connected between the positive output end and the negative output end. According to the cascaded energy storage power module provided by the utility model, more reliable and low-cost doubled frequency filtering can be realized in the cascaded energy storage power module through the doubled frequency parallel resonance design, and the influence caused by doubled frequency components is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of new energy storage technology, and in particular to a cascade energy storage power module and a high-power cascade energy storage device. Background Art

[0002] At present, the proportion of renewable energy in power generation continues to increase, but renewable energy power generation has its own instability, so the energy storage converter (PCS) that can "shift peaks and fill valleys" has come into being. High-power cascade energy storage devices usually use chain multi-level commutation technology, including dozens or even hundreds of energy storage power modules. Due to the self-generated characteristics of the cascade energy storage module, there is a double frequency current, and the double frequency and high frequency components will greatly reduce the life of the energy storage battery and affect the charging and discharging of the energy storage battery. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model proposes a cascaded energy storage power module, which can realize more reliable and low-cost double frequency filtering inside through double frequency parallel resonance design to solve the impact of double frequency components.

[0004] The utility model also provides a high-power cascade energy storage device.

[0005] According to the first aspect of the present invention, the cascaded energy storage power module includes:

[0006] An H-bridge converter having a positive output terminal and a negative output terminal, wherein the H-bridge converter is used to convert alternating current into direct current and output the direct current through the positive output terminal and the negative output terminal;

[0007] A first capacitor, one end of which is connected to the positive output end;

[0008] a battery pack, a positive electrode of which is connected to the other end of the first capacitor, and a negative electrode of which is connected to the negative output end;

[0009] a first inductor connected in parallel with the first capacitor; the first capacitor and the first inductor form a parallel resonant circuit, and the parallel resonant circuit is used to prevent the double frequency current from flowing to the battery pack;

[0010] The second capacitor is connected between the positive output terminal and the negative output terminal.

[0011] The cascaded energy storage power module according to the embodiment of the utility model has at least the following gain effects:

[0012] In the embodiment of the utility model, the cascade energy storage power module is composed of an H-bridge converter, a battery pack, a first capacitor, a first inductor and a second capacitor, and the first capacitor, the first inductor and the second capacitor constitute a DC side filter circuit arranged between the H-bridge converter and the battery pack, wherein the first capacitor and the first inductor together constitute a parallel resonant circuit, which can suppress the double frequency current, and at the same time, the second capacitor and the parallel resonant circuit composed of the first capacitor and the first inductor together constitute a filter circuit, realizing double frequency filtering. Through the double frequency parallel resonance design, the first capacitor and the first inductor together constitute a parallel resonant circuit, wherein the parallel resonant inductance value is relatively small, and compared with the series resonant circuit, the equipment charge and discharge switching response speed is improved, and at the same time, the parallel resonant inductance precision requirement is reduced, the equipment cost is reduced, and the system reliability is improved. In addition, the DC side filter circuit composed of the first capacitor, the first inductor and the second capacitor in the above technical solution of the utility model has a simple and reliable structure, and can achieve an ideal double frequency filtering effect without adding an additional control circuit, and has a high practical value.

[0013] According to some embodiments of the present utility model, the cascade energy storage power module further includes a first filtering unit, and the first filtering unit is connected in series between the other end of the first capacitor and the positive electrode of the battery pack.

[0014] According to some embodiments of the present invention, the first filtering unit is a second inductor, and the second inductor is connected in series between the other end of the first capacitor and the positive electrode of the battery pack.

[0015] According to some embodiments of the present utility model, the cascade energy storage power module further includes a second filtering unit, and the second filtering unit is connected in parallel with the second capacitor.

[0016] According to some embodiments of the present invention, the second filtering unit includes:

[0017] A third capacitor, one end of which is connected to the positive output terminal;

[0018] The third inductor is connected between the other end of the third capacitor and the negative output end.

[0019] The high-power cascade energy storage device according to the second embodiment of the utility model includes the cascade energy storage power module as described in the first embodiment. The high-power cascade energy storage device in the utility model embodiment includes the cascade energy storage power module as described in the first embodiment, and thus has all the beneficial effects of the cascade energy storage power module as described in the first embodiment.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0022] Figure 1 This is a first circuit diagram of a cascaded energy storage power module according to an embodiment of the utility model;

[0023] Figure 2 This is a schematic diagram of a second circuit of a cascaded energy storage power module according to an embodiment of the utility model.

[0024] Reference numerals:

[0025] A first filtering unit 100 and a second filtering unit 200 . DETAILED DESCRIPTION

[0026] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0027] In the description of the present utility model, if there is a description of first, second, etc., it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0028] In the description of the present invention, it should be understood that the descriptions involving orientation, such as the orientation or positional relationship indicated as up, down, etc., are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0029] In the description of the present utility model, it should be noted that, unless otherwise clearly stated, terms such as limitation, setting, installation, connection, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present utility model based on the specific content of the technical solution.

[0030] The technical solution of the present utility model will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described below are only part of the embodiments of the present utility model, not all of the embodiments.

[0031] Refer to the following Figure 1 to Figure 2 The cascaded energy storage power module of the embodiment of the present application is described.

[0032] The cascade energy storage power module of the utility model is as follows: Figure 1 As shown, it includes an H-bridge converter, a first capacitor, a battery pack, a first inductor and a second capacitor;

[0033] An H-bridge converter has a positive output terminal and a negative output terminal, and the H-bridge converter is used to convert AC power into DC power and output it through the positive output terminal and the negative output terminal;

[0034] A first capacitor, one end of which is connected to the positive output terminal;

[0035] A battery pack, a positive electrode of which is connected to the other end of the first capacitor, and a negative electrode of which is connected to the negative output end;

[0036] A first inductor is connected in parallel with the first capacitor; the first capacitor and the first inductor form a parallel resonant circuit, and the parallel resonant circuit is used to prevent the double frequency current from flowing to the battery pack;

[0037] The second capacitor is connected between the positive output terminal and the negative output terminal.

[0038] The cascade energy storage power module is composed of an H-bridge converter, a battery pack, and a DC side filter circuit, wherein the DC side filter circuit is composed of a first capacitor, a first inductor, and a second capacitor, and the DC side filter circuit is arranged between the H-bridge converter and the battery pack as a filter device. The H-bridge converter is composed of switching devices, and the H-bridge converter has rectification and inversion functions. The AC side of the H-bridge converter is connected to the AC power grid, and the DC side is connected to the battery pack through the DC side filter circuit; the battery pack can realize the storage of electric energy.

[0039] The DC side filter circuit is composed of a first capacitor, a first inductor and a second capacitor, wherein the circuit composed of the first capacitor and the first inductor adopts a double frequency parallel resonance design. When there is a double frequency current flowing out of the H-bridge converter, the impedance of the parallel resonant circuit composed of the first capacitor and the first inductor will become very large, which will hinder the double frequency current from flowing to the battery pack; at the same time, the parallel resonant circuit composed of the first capacitor and the first inductor constitutes a filter circuit with the second capacitor, and the double frequency current blocked by the parallel resonant circuit composed of the first capacitor and the first inductor will flow into the second capacitor, reducing the double frequency current flowing into the battery pack, thereby realizing double frequency filtering.

[0040] The circuit composed of the first capacitor and the first inductor adopts a double-frequency parallel resonance design. Compared with the series resonance circuit, the parallel resonance inductance is relatively small, and the charging and discharging switching response speed of the equipment is improved. At the same time, the parallel resonance reduces the accuracy requirements of the inductor, which further reduces the equipment cost compared to the series resonance circuit, and at the same time improves the reliability of the system.

[0041] When in the energy storage state, electric energy flows from the AC power grid to the battery pack, and the H-bridge converter converts the AC power into DC power through rectification and stores it in the battery pack; when in the discharge state, electric energy flows from the battery pack to the AC power grid, and the H-bridge converter converts the DC power stored in the battery pack into AC power through inversion and outputs it to the AC power grid.

[0042] In the embodiment of the utility model, the cascade energy storage power module is composed of an H-bridge converter, a battery pack, a first capacitor, a first inductor and a second capacitor, and the first capacitor, the first inductor and the second capacitor constitute a DC side filter circuit arranged between the H-bridge converter and the battery pack, wherein the first capacitor and the first inductor together constitute a parallel resonant circuit, which can suppress the double frequency current, and at the same time, the second capacitor and the parallel resonant circuit composed of the first capacitor and the first inductor together constitute a filter circuit, realizing double frequency filtering. Through the double frequency parallel resonance design, the first capacitor and the first inductor together constitute a parallel resonant circuit, wherein the parallel resonant inductance value is relatively small, and compared with the series resonant circuit, the equipment charge and discharge switching response speed is improved, and at the same time, the parallel resonant inductance precision requirement is reduced, the equipment cost is reduced, and the system reliability is improved. In addition, the DC side filter circuit composed of the first capacitor, the first inductor and the second capacitor in the above technical solution of the utility model has a simple and reliable structure, and can achieve an ideal double frequency filtering effect without adding an additional control circuit, and has a high practical value.

[0043] In some embodiments, in actual use, appropriate values ​​of the first inductor, the first capacitor, and the second capacitor can be selected according to the switching frequency and high-order harmonic content of the H-bridge converter and combined with the device parameters of the equipment itself to better filter out the second-frequency harmonics in the current.

[0044] In some embodiments, Figure 2 As shown, the cascade energy storage power module further includes a first filter unit 100, and the first filter unit 100 is connected in series between the other end of the first capacitor and the positive electrode of the battery pack.

[0045] In some embodiments, Figure 2 As shown, the first filtering unit 100 is a second inductor, and the second inductor is connected in series between the other end of the first capacitor and the positive electrode of the battery pack. The second inductor can form a filtering circuit with the second capacitor.

[0046] In some embodiments, Figure 2 As shown, the cascade energy storage power module further includes a second filtering unit 200, and the second filtering unit 200 is connected in parallel with the second capacitor.

[0047] In some embodiments, Figure 2 As shown, the second filtering unit 200 includes a third capacitor and a third inductor;

[0048] A third capacitor, one end of which is connected to the positive output terminal;

[0049] The third inductor is connected between the other end of the third capacitor and the negative output end.

[0050] In the second filtering unit 200, the third capacitor and the third inductor are connected in series to form a series resonant circuit, and the resonant frequency of the series resonant circuit is twice the frequency of the AC power grid.

[0051] The embodiment of the utility model also proposes a high-power cascade energy storage device, which includes the cascade energy storage power module as described in the above embodiment. The high-power cascade energy storage device in the embodiment of the utility model includes the cascade energy storage power module as described in the above embodiment, and thus has all the beneficial effects of the cascade energy storage power module as described in the embodiment of the first aspect.

[0052] The high-power cascade energy storage device adopts multiple cascade energy storage power modules in the embodiments of the utility model, which can achieve more reliable and low-cost double frequency filtering inside the high-power cascade energy storage device and solve the impact of the double frequency component.

[0053] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0054] Although the embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, the present invention is not limited to the above embodiments. Those skilled in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and purpose of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A cascade energy storage power module, characterized in that: include: An H-bridge converter having a positive output terminal and a negative output terminal, wherein the H-bridge converter is used to convert alternating current into direct current and output the direct current through the positive output terminal and the negative output terminal; A first capacitor, one end of which is connected to the positive output end; a battery pack, a positive electrode of which is connected to the other end of the first capacitor, and a negative electrode of which is connected to the negative output end; a first inductor connected in parallel with the first capacitor; the first capacitor and the first inductor form a parallel resonant circuit, and the parallel resonant circuit is used to prevent the double frequency current from flowing to the battery pack; The second capacitor is connected between the positive output terminal and the negative output terminal.

2. The cascade energy storage power module according to claim 1, characterized in that: The cascade energy storage power module further includes a first filtering unit, which is connected in series between the other end of the first capacitor and the positive electrode of the battery pack.

3. The cascade energy storage power module according to claim 2, characterized in that: The first filtering unit is a second inductor, and the second inductor is connected in series between the other end of the first capacitor and the positive electrode of the battery pack.

4. The cascade energy storage power module according to claim 1, characterized in that: The cascade energy storage power module also includes a second filtering unit, and the second filtering unit is connected in parallel with the second capacitor.

5. The cascade energy storage power module according to claim 4, characterized in that: The second filtering unit comprises: A third capacitor, one end of which is connected to the positive output terminal; The third inductor is connected between the other end of the third capacitor and the negative output end.

6. A high-power cascade energy storage device, characterized in that: It comprises a plurality of cascaded energy storage power modules as described in any one of claims 1 to 5.

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