Flexible distribution transformer and installation equipment for AC / DC power distribution network

Abstract

The invention relates to the technical field of alternating-current and direct-current power distribution, in particular to a flexible power distribution transformer for an alternating-current and direct-current power distribution network and installation equipment, and discloses the flexible power distribution transformer for the alternating-current and direct-current power distribution network. And the high-voltage side coil, the alternating-current low-voltage side coil, the direct-current low-voltage side coil and the direct-current low-voltage side coil with adjustable turns are connected with a series power module for voltage compensation and a parallel power module for current compensation. The beneficial effects of the invention are that a principle of magnetic field coupling balance of multiple power supplies in a magnetic loop is adopted to achieve the purpose of energy flow and interaction control in different directions, and the flexible adjustment of voltage and current at the low-voltage end of the transformer and the convenient access and interaction of the direct-current power supply and the direct-current load are realized; and the requirements of power distribution network voltage bidirectional cross-border treatment, current-related electric energy quality treatment and convenient access and interaction of a direct-current power supply and a load in novel power system application are met.

Description

Technical Field

[0001] The present invention relates to the technical field of AC and DC power distribution, and in particular to a flexible distribution transformer and installation equipment for an AC and DC power distribution network. Background Art

[0002] With the construction of new power systems, a large number of new energy sources such as photovoltaics and wind power are connected to the power grid from the grid side or the load side of the distribution network. The distribution network has changed from the traditional simple load end to a coexistence of load and distributed energy. The distribution network has also changed from the traditional "passive" one-way radiation network to an "active" two-way interactive distribution network.

[0003] The traditional distribution network is a single-phase power flow from power generation - transmission - distribution, while the distribution network in the new power system is an active distribution network connected to various distributed energy sources, that is, there is a traditional power supply flow from the high-voltage side to the low-voltage side, and there is also a flow of reverse transmission to the high-voltage side after the low-voltage distributed energy is in excess.

[0004] In traditional distribution networks, power quality management is mostly about one problem corresponding to one power quality management device, such as voltage regulation device, reactive power compensation device, harmonic management device, three-phase current imbalance management device; while in new power systems, voltage over-limit problems, three-phase current imbalance problems, low power factor, high harmonic content and other problems often exist simultaneously. Summary of the invention

[0005] Some simplifications or omissions may be made in this section and the abstract and title of the present application to avoid obscuring the purpose of this section, the abstract and the title of the invention, and such simplifications or omissions shall not be used to limit the scope of the present invention.

[0006] In view of the above-mentioned prior art problems, the present invention is proposed.

[0007] The purpose of the present invention is to provide a flexible distribution transformer for AC and DC distribution networks, which aims to solve the obvious deficiencies of distribution equipment in traditional distribution networks in dealing with new energy access, complex power quality management, and power flow interaction.

[0008] To solve the above technical problems, the present invention provides the following technical solutions: a flexible distribution transformer for an AC / DC power distribution network, comprising a high-voltage side coil with adjustable turns, an AC low-voltage side coil, and a DC low-voltage side coil, wherein the DC low-voltage side coil is connected to a series power module for voltage compensation and a parallel power module for current compensation.

[0009] As a preferred solution of the flexible distribution transformer for AC / DC power distribution network of the present invention, wherein: the high-voltage side coil is connected to at least one switch, and each switch is connected in parallel.

[0010] As a preferred solution of the flexible distribution transformer for AC / DC power distribution network of the present invention, the switch, the series power module and the parallel power module are connected to the master control device.

[0011] As a preferred solution of the flexible distribution transformer for AC / DC power distribution network of the present invention, the master control device includes a transformer on-load voltage regulator controller, a voltage compensation power module controller, and a current compensation power module controller.

[0012] As a preferred solution of the flexible distribution transformer for AC / DC power distribution network of the present invention, the series power modules and the parallel power modules are directly interconnected back to back.

[0013] As a preferred solution of the flexible distribution transformer for AC / DC power distribution network of the present invention, wherein: the high-voltage side coil is externally connected to AC power.

[0014] As a preferred solution of the flexible distribution transformer for AC / DC power distribution network of the present invention, the parallel power module is externally connected to the DC side low-voltage distribution network.

[0015] As a preferred solution of the flexible distribution transformer for AC / DC power distribution network of the present invention, the AC low-voltage side coil is externally connected to a load.

[0016] The beneficial effects of the flexible distribution transformer for AC and DC distribution networks of the present invention are as follows: the present invention adopts the principle of magnetic field coupling balance of multiple power sources in a magnetic circuit to achieve the purpose of energy flow and interactive control in different directions, realizes flexible regulation of voltage and current at the low-voltage end of the transformer, and convenient access and interaction between the DC power supply and the DC load, and meets the needs of bidirectional voltage cross-border management of distribution network, management of current-related power quality, and convenient access and interaction between the DC power supply and the load in new power system applications.

[0017] Another object of the present invention is to provide a componentized intelligent control terminal that supports orderly electricity use, which aims to solve the problem of equipment installation.

[0018] In order to solve the above technical problems, the present invention also provides the following technical solutions: a componentized intelligent control terminal that supports orderly electricity consumption.

[0019] As a preferred solution of the flexible distribution transformer for AC / DC power distribution network of the present invention, wherein: the installation equipment is provided with corresponding installation brackets according to the requirements of the flexible distribution transformer for AC / DC power distribution network.

[0020] The flexible distribution transformer for AC and DC power distribution networks of the present invention has the beneficial effect of providing installation equipment for the flexible distribution transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0022] Figure 1 The schematic diagram of the flexible distribution transformer for AC and DC distribution network in the present invention.

[0023] Figure 2 This is a typical working scenario in which the 10kV port in the present invention supplies power to the low-voltage side, the total current of the low-voltage AC side port flows to the load side, and the total current of the low-voltage DC side port flows to the load side.

[0024] Figure 3 This is a typical working scenario in which the 10kV port in the present invention supplies power to the low-voltage side, the total current of the low-voltage AC side port flows to the load side, and the total current of the low-voltage DC side port flows to the power supply side.

[0025] Figure 4 This is a typical working scenario in which the 10kV port in the present invention supplies power to the low-voltage side, the total current of the low-voltage AC side port flows to the power supply side, and the total current of the low-voltage DC side port flows to the load side.

[0026] Figure 5 This is a typical working scenario in which the low-voltage AC side port in the present invention supplies power to 10kV, the total current of the low-voltage AC side port flows to the power supply side, and the total current of the low-voltage DC side port flows to the load side.

[0027] Figure 6 This is a typical working scenario in which the low-voltage AC side port and the low-voltage DC side port in the present invention simultaneously supply power to 10kV, the total current of the low-voltage AC side port flows to the power supply side, and the total current of the low-voltage DC side port flows to the power supply side.

[0028] Figure 7 This is a typical working scenario in which the low-voltage DC side port in the present invention supplies power to 10kV, the total current of the low-voltage AC side port flows to the load side, and the total current of the low-voltage DC side port flows to the power supply side.

[0029] Figure 8 This is an appearance diagram of the installation equipment in the present invention. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0031] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0032] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments.

[0033] Example 1

[0034] Reference Figure 1 , which is the first embodiment of the present invention, provides a flexible distribution transformer for an AC / DC distribution network.

[0035] like Figure 1 As shown, the flexible distribution transformer in the present invention includes a winding structure with a common iron core including a high-voltage side coil 101, a switch, an AC low-voltage side coil 102, and a DC low-voltage side coil 103, wherein the number of turns of the high-voltage side winding coil composed of the high-voltage side coil 101 and the switch can be changed by controlling the tap switches K1 to K5, taking a 5-speed tap switch as an example, and then the magnetic flux in the iron core of the high-voltage side coil 101 is changed by changing the number of coil turns.

[0036] When the high-voltage coil, usually the primary coil of the transformer, is connected to a sinusoidal AC voltage, this voltage will generate a changing magnetic flux in the iron core of the transformer. This changing magnetic flux is due to the characteristics of AC, that is, the current and voltage change periodically over time. The iron core is usually made of magnetic materials, such as silicon steel sheets, which can effectively guide the magnetic flux and reduce magnetic resistance, thereby improving the efficiency of the magnetic field.

[0037] In a three-winding transformer, all three coils are wound on the same core. This design allows each coil to sense the same flux changes because the core is shared. This configuration allows the transformer to step the voltage up or down as needed.

[0038] When the magnetic flux changes in the core, it induces an AC voltage in each coil. The magnitude of the induced voltage depends on the number of turns in the coil. According to Faraday's law of electromagnetic induction, the voltage induced in the coil is proportional to its number of turns and the rate of change of the magnetic flux. Therefore, if the high-voltage side coil has more turns, the induced voltage will be higher, and vice versa. This is why transformers can be used to change voltage levels.

[0039] The magnetomotive force induced by the magnetic flux Φ flowing through the three windings is:

[0040]

[0041] Among them, e1, e2, and e3 are the potentials at both ends of the high-voltage side coil 101 and the switch closing point, the potentials at both ends of the AC low-voltage side coil 102, and the potentials at both ends of the DC low-voltage side coil 103 respectively; as shown in Figure X, U S It is an external voltage. When the voltage on the secondary side of the three-winding transformer needs to be adjusted, the number of turns of the high-voltage coil 101 can be adjusted to change the change in the e1 magnetic flux, thereby adjusting the other two voltages.

[0042] The advantage of this design is that by separating the DC and AC inputs, the mutual impact can be reduced, thus achieving energy flow and interactive control between the DC and AC sides.

[0043] Example 2

[0044] Reference Figures 1 to 7 , which is the second embodiment of the present invention.

[0045] Through the series power module 104 and the parallel power module 105 directly interconnected back to back, the power devices can change the voltage and current at both ends of the DC low-voltage side coil 103 and thus change the magnetic flux in the iron core; under the control of the master control device 106, the above two types of iron core magnetic fluxes are controlled and the voltage on the AC side of the switch and the high-voltage side coil 101 can meet the needs of the use scenario.

[0046] The voltage and current at both ends of the DC low-voltage side coil 103 can be adjusted by directly interconnecting the series power module 104 and the parallel power module 105 back to back. These power modules usually include multiple power electronic devices, such as IGBT insulated gate bipolar transistors or MOSFET metal oxide semiconductor field effect transistors, which are prior arts and will not be described in detail; they can be switched on and off quickly to change the direction and magnitude of the current passing through the coil.

[0047] The function of the series power module 104 is to add an additional voltage source on the DC side. By adjusting the polarity and size of the voltage source, the total voltage at both ends of the coil can be changed. The parallel power module 105 changes the current at both ends of the coil by increasing or decreasing the number of parallel branches. Both methods can change the magnetic flux in the core because the magnetic flux is proportional to the voltage and current at both ends of the coil.

[0048] Under the control of the master control device 106, the system can accurately control the working state of the series and parallel power modules, thereby accurately controlling the magnetic flux in the core. This control is usually achieved through complex control algorithms that can respond to external instructions or internal feedback signals to ensure that the system operates according to predetermined performance parameters.

[0049] Finally, by adjusting the magnetic flux in the core, the voltage and current of the motor or other load connected to the AC side of the high-voltage side coil 101 can be controlled. In this way, the system can accurately adjust its output according to the needs of the actual application, such as starting, accelerating, decelerating or stopping the motor, to meet different working conditions.

[0050] This highly flexible control method enables the power system to adapt to changing load demands, improve energy efficiency, reduce energy waste, and ensure stable operation of the system. In addition, by precisely controlling the magnetic flux, it can also reduce the electromagnetic interference of the motor, extend the service life of the equipment, and improve the reliability of the entire system.

[0051] Specifically, when the transformer secondary voltage needs to be adjusted, the main magnetic flux can be controlled by adjusting the third winding current.

[0052] N1I1+N2I2+N3I3=0

[0053] Due to the change of N3I3, in order to maintain the balance of magnetomotive force, the magnetomotive force generated by the current and / or number of turns of other windings including the main winding must also change accordingly, so the main magnetic flux will change.

[0054]

[0055]

[0056] Therefore, without changing other conditions, the terminal voltages of the other two windings can be changed by adjusting the current it in the figure.

[0057] Furthermore, the present invention realizes the regulation of the AC side voltage of the switch and the high-voltage side coil 101 through the high-voltage side coil 101, the AC low-voltage side coil 102, and the DC low-voltage side coil 103, and can also realize the compensation and control of current-related interference in the switch loop through the parallel end of the parallel power module 105, such as capacitive / inductive reactive power compensation, control of harmonic current, and control of phase current imbalance;

[0058] Furthermore, the DC power supply and the DC load can be conveniently connected through the DC side low-voltage distribution network between the series power module 104 and the parallel power module 105 to control the power flow.

[0059] Specifically: Use PV Indicates the power generated by the AC side distributed power supply, P L Indicates the AC side load, P ess Indicates the DC side power supply, P dkl Indicates the DC side load.

[0060] On the one hand, when the distributed generation generates power P V >P L , P ess <P dkl , the power module 104 can be connected in series to allow the power on the high-voltage side tap switch to flow to the load on the low-voltage distribution network side of the DC side.

[0061] P V -P L >P dkl

[0062] The DC power supply is turned on by the master control device 106 to store energy.

[0063] P V -P L -P dkl >P ess

[0064] The remaining electric energy flows to the grid. The device can minimize the electric energy sent back to the grid, thus ensuring the quality of electric energy.

[0065] On the other hand, when the distributed generation generates power P V <P L , P ess >P dkl , the DC power supply is turned on by the master control device 106 for discharge, and the power module 104 is connected in series to allow the power on the DC low-voltage distribution network side to flow to the switch side load.

[0066] P ess -P dcL <P v -P L P ess -P dkl <P V -P L

[0067] Then obtain electricity from the grid if:

[0068] P ess -P dcL ≥P v -P L P ess -P dkl ≥P V -P L

[0069] There is no need to obtain electricity from the power grid. The equipment can reasonably utilize electricity to the greatest extent and improve economic benefits.

[0070] Example 3

[0071] Reference Figure 8 , which is the third embodiment of the present invention, and this embodiment further provides an installation device. The series power module 104, the parallel power module 105, the master control device 106 and the low-voltage components in the whole device are installed in a box. Of course, considering the design and use scenarios of the product, the series power module 104, the parallel power module 105, the master control device 106 can also be designed and installed in an integrated manner with other components.

[0072] Importantly, it should be noted that the construction and arrangement of the present application shown in a plurality of different exemplary embodiments are only exemplary. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible (e.g., the size, scale, structure, shape and proportion of various elements, as well as parameter values ​​(e.g., temperature, pressure, etc.), mounting arrangements, use of materials, color, directional changes, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in the application. For example, the element shown as integrally formed can be composed of multiple parts or elements, the position of the element can be inverted or otherwise changed, and the nature or number or position of the discrete element can be changed or changed. Therefore, all such modifications are intended to be included in the scope of the present invention. The order or sequence of any process or method steps can be changed or reordered according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure described herein that performs the function, and is not only structurally equivalent but also equivalent structure. Without departing from the scope of the present invention, other replacements, modifications, changes and omissions can be made in the design, operating conditions and arrangement of the exemplary embodiments. Therefore, the invention is not limited to a specific embodiment, but extends to several modifications still falling within the scope of the appended claims.

[0073] Additionally, in order to provide a concise description of exemplary embodiments, all features of an actual embodiment (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention) may not be described.

[0074] It will be appreciated that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but will be a routine task of design, fabrication, and production for those of ordinary skill having the benefit of this disclosure without undue experimentation.

[0075] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A flexible distribution transformer for an AC / DC distribution network, characterized in that: The invention comprises a high-voltage side coil (101) with an adjustable number of turns, an AC low-voltage side coil (102), and a DC low-voltage side coil (103); the DC low-voltage side coil (103) is connected to a series power module (104) for voltage compensation and a parallel power module (105) for current compensation.

2. The flexible distribution transformer for AC / DC power distribution network according to claim 1, characterized in that: The high-voltage side coil (101) is connected to at least one switch, and each switch is connected in parallel.

3. The flexible distribution transformer for AC / DC power distribution network according to claim 2, characterized in that: The switch, the series power module (104) and the parallel power module (105) are connected to a master control device (106).

4. The flexible distribution transformer for AC / DC power distribution network according to claim 3, characterized in that: The master control device (106) comprises a transformer on-load voltage regulation controller, a voltage compensation power module controller, and a current compensation power module controller.

5. The flexible distribution transformer for AC / DC power distribution network according to claim 4, characterized in that: The series power modules (104) and the parallel power modules (105) are directly interconnected back to back.

6. The flexible distribution transformer for AC / DC power distribution network according to claim 5, characterized in that: The high-voltage side coil (101) is externally connected to alternating current.

7. The flexible distribution transformer for AC / DC power distribution network according to claim 6, characterized in that: The parallel power module (105) is externally connected to a DC-side low-voltage distribution network.

8. The flexible distribution transformer for AC / DC power distribution network according to claim 7, characterized in that: The AC low-voltage side coil (102) is externally connected to a load.

9. A mounting device, characterized in that: include: A flexible distribution transformer for an AC / DC distribution network as claimed in any one of claims 1 to 8.

10. The mounting device according to claim 9, characterized in that: The installation equipment is provided with corresponding installation brackets according to the requirements of the flexible distribution transformer used in the AC and DC power distribution network.

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