CN108258676A - Complete controllable flexibly distribution system and method based on direct current multiport electric energy exchanger - Google Patents

Abstract

The invention relates to a fully controllable and flexible power distribution system and method based on a DC multi-port power exchanger. The system is composed of a plurality of power distribution node hierarchical networking models of different voltage levels connected to each other. The single power distribution node level The networking model includes DC multi-port power exchangers and their loads, and the loads include various power units and distributed power sources; at the same time, the number of AC-DC converters in the distribution network can be reduced by concentrating AC and DC ports to realize The purpose of seamless control of AC and DC in a power distribution port and the efficient integration and utilization of multiple energy sources. By concentrating the AC ports and DC ports of the corresponding voltage levels in the DC multi-port power exchanger, it realizes the connection between the medium, high and low voltage AC and DC distribution networks, the AC and DC distribution network and distributed power sources, energy storage devices and power consumption units Between, the two-way flow of energy and information data.

Description

Fully controllable flexible power distribution system and method based on DC multi-port power exchanger

technical field

The invention relates to a hierarchical network flexible power distribution system, in particular to a fully controllable flexible power distribution system and method based on a DC multi-port power exchanger.

Background technique

The access of a large number of distributed power sources, microgrids and flexible loads makes the traditional distribution network evolve into the coexistence of AC distribution network and DC microgrid. The AC distribution network still uses the structure and control characteristics of the traditional distribution network, which cannot meet the user's requirements for the power quality of the distribution network and the customized power consumption of various forms of electric energy; at the same time, the user is currently relying on the user to ensure the power quality and a large number of decentralized rectification devices. The method of DC load power supply not only increases the cost, is prone to power quality problems, but also seriously reduces energy efficiency. On the other hand, the energy efficiency and economy of the DC microgrid have been questioned, and in order to adapt to the massive access of distributed power sources and flexible loads, as shown in Figure 1, the AC-DC converters required to form the future DC distribution network The rapid increase in the number makes the system structure complex and the control difficulty increased.

In addition, the demand for power users to deeply participate in the operation and management of the distribution network is becoming stronger and stronger, and they are eager to change the current mode of centralized control and passive management, and establish a hierarchical and progressive combination of centralization and distribution from the structure of the distribution network itself Active control framework.

Contents of the invention

In order to solve the deficiencies in the above-mentioned prior art, the purpose of the present invention is to provide a fully controllable and flexible power distribution system and method based on DC multi-port power exchangers, the present invention is applicable to the multi-port The DC power exchanger and the AC-DC seamless fully controllable and flexible power distribution system centered on this kind of DC power exchanger can effectively solve the above problems.

The object of the present invention is to adopt following technical scheme to realize:

The present invention provides an AC-DC fully controllable flexible power distribution system based on a DC multi-port power exchanger. The improvement is that the power distribution system is composed of a plurality of single power distribution node hierarchical networking models connected to each other. The hierarchical networking model of a single power distribution node includes DC multi-port power exchangers of different voltage levels and their loads. The loads include various power units, distributed power sources, and energy storage. The port power exchangers are connected to each other;

By concentrating the AC ports and DC ports of the corresponding voltage levels in the DC multi-port power exchanger, it can realize the connection between medium, high and low voltage AC and DC distribution networks, between AC and DC distribution networks and distributed power sources, energy storage devices and power consumption units Between the two-way flow of energy and information data; at the same time, the centralized method of AC and DC ports reduces the number of AC-DC converters in the distribution network, and realizes the seamless control of AC and DC in a power distribution port.

Further, the DC multiport power exchangers of different voltage levels include high voltage DC multiport power exchangers and medium and low voltage DC multiport power exchangers;

The input side of the high-voltage direct current multi-port power exchanger is interconnected through a high-voltage direct current bus, thereby realizing a high-voltage direct current networking layer based on the power exchanger;

The output side of the high-voltage DC multi-port power exchanger is interconnected through the medium-voltage DC bus to form a medium-voltage DC networking layer based on the power exchanger;

The input side of the medium and low voltage DC multi-port power exchanger is interconnected through the medium and low voltage DC bus to realize the medium and low voltage DC networking layer based on the power exchanger;

Through the interconnection of the high voltage DC network layer, the medium and high voltage AC network layer and the medium and low voltage DC network layer, the AC and DC fully controllable and flexible power distribution system is formed based on the power distribution nodes of the DC multi-port power exchanger.

Further, the voltage level of the high-voltage DC bus in the high-voltage DC networking layer is 90kV-180kV, the voltage level of the high-voltage DC bus in the medium-high-voltage AC networking layer is 1.5kV-90kV, and the medium-low voltage DC networking layer The voltage level of the medium and low voltage DC bus on the first floor is 5V~1.5kV.

Further, the DC multi-port power exchangers of different voltage levels include an electrical information layer and an electrical physical layer connected to each other; the electrical information layer includes a monitoring module, an intelligent control module, a communication module and an information processing module; the electrical The physical layer includes a power electronic solid-state module and a power interface module; the intelligent control module is connected to the power electronic solid-state module.

Further, the power electronic solid-state module includes a solid-state module controller, a power electronic switch tube, a protection and drive module, and a sensing module connected in sequence; the power interface module includes a high-voltage AC interface, a high-voltage DC interface, and a power frequency AC interface. and medium voltage DC interface;

The DC multi-port power exchangers of different voltage levels realize the communication and information plug-and-play of the power exchangers in the AC and DC power distribution area and between different levels through the conversion of the communication protocol and the power interface module, forming a physical information model .

Further, the output-side port types of the DC multi-port power exchangers of different voltage levels include: AC-DC ports and DC ports; the AC-DC ports include sub-interfaces with different voltage levels and different functions; In the way of DC multi-port power exchangers of different voltage levels, the seamless connection of AC and DC lines in the distribution network is realized;

Among the AC and DC ports, the voltage level of the high-voltage AC interface is 120kV-500kV; the voltage level of the medium-voltage AC interface is 2kV-120kV; the voltage level of the low-voltage AC interface is below 400V.

The interfaces with different functions include load interfaces, energy storage interfaces, distributed generation grid connection interfaces, charging pile interfaces and power supply interfaces.

Further, the AC/DC or DC/AC converter in the power electronic solid-state module topology selects one of the multilevel topology structures according to the voltage level, and the number of modules in the multilevel topology structure depends on the DC voltage or the AC voltage Level, multi-level topology includes single-arm topology of diode clamping (NPC), H-bridge cascaded topology and modular multi-level MMC topology. The number of levels of the multi-level structure adopted is determined according to the voltage level in the application ;

The single-arm topology of the diode-embedded NPC is actually selected according to the power level of the NPC single-arm or three-phase three-arm topology, and the corresponding intermediate high-frequency isolation transformer adopts a single-phase or three-phase structure; the H-bridge stage The H-bridge in the multi-level topology and modular multilevel MMC topology adopts single-phase or three-phase topology according to the power level, and the transformer adopts corresponding changes.

The present invention also provides a power distribution method for an AC and DC fully controllable flexible power distribution system, the improvement of which is that the method includes:

Step 1: Determine the hierarchical networking model of a single distribution node in the fully controllable flexible distribution system;

Step 2: Combine multiple fully controllable flexible power distribution systems with a single power distribution node hierarchical networking model to form an AC and DC fully controllable flexible power distribution system.

Further, said step 1 includes:

Connect DC multi-port power exchangers of different voltage levels to each other to form a single node hierarchical networking model;

The DC multiport power exchangers of different voltage levels include high voltage DC multiport power exchangers and medium and low voltage DC multiport power exchangers;

The input side of the high-voltage direct current multi-port power exchanger is interconnected through a high-voltage direct current bus, thereby realizing a high-voltage direct current networking layer based on the power exchanger;

The output side of the high-voltage DC multi-port power exchanger is interconnected through the medium-high voltage AC busbar, forming a medium-high voltage AC networking layer based on the power exchanger;

The input side of the medium and low voltage DC multi-port power exchanger is interconnected through the medium and low voltage DC bus to realize the medium and low voltage DC networking layer based on the power exchanger;

Through the interconnection of the high voltage DC network layer, the medium and high voltage AC network layer and the medium and low voltage DC network layer, the AC and DC fully controllable and flexible power distribution system based on the DC multi-port power exchanger is formed.

Further, in the step 2, a plurality of single-node hierarchical networking models are connected to each other to form an AC-DC fully controllable flexible power distribution system, by concentrating the AC ports and DC ports of different voltage levels on the DC multi-port DC power exchanger The way of the load side of the medium and high voltage DC distribution network is realized to supply power to the AC and DC loads, and the energy of the medium and high voltage DC distribution network and the distributed power supply and the energy storage device can flow bidirectionally; at the same time, the centralized method of the AC and DC ports reduces the power distribution The number of AC-DC converters in the network can be adjusted to realize seamless control of AC-DC in one power distribution port.

In order to provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is presented below. This summary is not an overview, nor is it intended to identify key/critical elements or delineate the scope of these embodiments. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.

Compared with the closest prior art, the excellent effect that the technical solution provided by the present invention has is:

The present invention proposes a multi-port DC power exchanger suitable for medium and high voltage DC distribution networks in the future, and an AC-DC seamless fully controllable and flexible power distribution system centered on this type of DC power exchanger. The system will accept Large-scale distributed power supply, energy storage, flexible load and other plug-and-play access and unified coordinated management to achieve multi-directional flow of energy, effectively improve energy utilization, save distributed access and future distribution network transformation costs. At the same time, the system can realize regional distribution autonomy, flexible power transformation, grid-like full peer-to-peer AC and DC seamless hybrid power distribution network, has self-healing, network reconstruction and immunity capabilities, and has extremely high power supply reliability , basically rule out the risk of large-scale power outages. The system will highly integrate the physical system of the power grid and the communication information system of the power grid, and will realize a comprehensive service system of energy, power and information covering urban and rural areas.

To the above and related ends, one or more embodiments comprise the features hereinafter specified and particularly pointed out in the claims. The following description and drawings detail certain exemplary aspects and are indicative of but a few of the various ways in which the principles of various embodiments may be employed. Other benefits and novel features will become apparent upon consideration of the following detailed description in conjunction with the accompanying drawings, and the disclosed embodiments are intended to include all such aspects and their equivalents.

Description of drawings

Figure 1 is a structural diagram of a distributed AC-DC hybrid power distribution system;

Fig. 2 is a single node model diagram of the AC-DC fully controllable flexible power distribution system based on the DC multi-port power exchanger provided by the present invention;

Fig. 3 is a hierarchical networking framework diagram of the AC-DC fully controllable flexible power distribution system based on the DC multi-port power exchanger provided by the present invention;

Fig. 4 is a structural diagram of a DC multi-port power exchanger provided by the present invention;

Fig. 5 is the topological structure diagram of the power electronics solid-state module of the DC multi-port power exchanger provided by the present invention, (a) is the structural block diagram of the power electronics solid-state module of the DC multi-port power exchanger; (b) the diode embedding of the DC/AC converter (NPC) single-arm topology; (c) is the DC/AC converter H-bridge cascaded (H-bridge cascaded) topology; (d) is the DC/AC converter modular multi-level ( MMC) topology map.

Detailed ways

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings.

The following description and drawings illustrate specific embodiments of the invention sufficiently to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. The examples merely represent possible variations. Individual components and functions are optional unless explicitly required, and the order of operations may vary. Portions and features of some embodiments may be included in or substituted for those of other embodiments. The scope of embodiments of the present invention includes the full scope of the claims, and all available equivalents of the claims. These embodiments of the present invention may be referred to herein, individually or collectively, by the term "invention", which is for convenience only and is not intended to automatically limit the application if in fact more than one invention is disclosed The scope is any individual invention or inventive concept.

Example 1

The present invention aims at problems such as the high penetration rate access of the current distribution network, customized electricity demand, too many AC/DC converters, and users participating in the operation and management of the distribution network, and innovates the structure mode and structure of the distribution network. Control mode, a multi-port DC power exchanger suitable for the future medium and high voltage DC power distribution network, and an AC-DC seamless fully controllable flexible power distribution system with this type of DC power converter as the core are proposed.

The power distribution system is composed of multiple single power distribution node hierarchical networking models connected to each other. The single power distribution node hierarchical networking model includes DC multi-port power exchangers of different voltage levels and their loads. The loads include various similar power consumption units, distributed power sources, and energy storage, etc., and the DC multi-port power exchangers of different voltage levels are connected to each other;

By concentrating the AC ports and DC ports of the corresponding voltage levels in the DC multi-port power exchanger, it can realize the connection between medium, high and low voltage AC and DC distribution networks, between AC and DC distribution networks and distributed power sources, energy storage devices and power consumption units Two-way flow of energy and information data (as shown in Figure 2); at the same time, the centralized method of AC and DC ports reduces the number of AC and DC converters in the distribution network, and realizes seamless control of AC and DC in a power distribution port.

Connect DC multi-port power exchangers of different voltage levels to form a hierarchical network flexible power distribution system (as shown in Figure 3), and realize hierarchical networking, seamless mixing, flexible controllability, intelligent management and distribution of AC and DC power It can effectively reduce the complexity of the active distribution network system, reduce the types and quantities of scattered equipment, improve the controllability and maintainability of operation, and significantly improve the future DC distribution network's impact on distributed power sources, microgrids and flexible loads. The ability to accept new elements.

The invention proposes a multi-port DC power exchanger suitable for future medium and high voltage DC power distribution networks, and an AC-DC seamless fully controllable and flexible power distribution system centered on the DC power exchanger. The input end of the DC multi-port power exchanger of the integrated electrical cyber-physical system is a medium-voltage DC input, and the output end is a medium-low voltage AC-DC centralized output port. The input side of the high-voltage DC multi-port power exchanger is interconnected through the high-voltage DC bus, thereby realizing the high-voltage DC networking layer (1.5kV~65kV) based on the power exchanger; the output side of the high-voltage DC multi-port power exchanger is connected through the medium-high voltage AC bus Realize interconnection and form a medium and high voltage AC networking layer (1kV~35kV) based on power exchangers; the input side of medium and low voltage DC multi-port power exchangers is interconnected through medium and low voltage DC buses to realize medium and low voltage DC groups based on power exchangers Network layer (5V ~ 800V). The AC and DC output interfaces of power exchangers of different voltage levels are connected to the lower-level power exchangers with corresponding voltage level input interfaces and the access of distributed power supplies, energy storage, flexible loads, etc. of corresponding voltage levels through bus bars; The voltage busbars in the layer are interconnected to form an AC-DC seamless and flexible power distribution system based on DC multi-port power exchangers. Relying on the power exchanger to realize the organic integration of power demand side management, distributed power supply, flexible load and distribution network, as well as plug-and-play between power supply and users and multi-quality power customization services for users. The voltage level of the high-voltage DC busbar in the high-voltage DC networking layer is 90kV～180kV, the voltage level of the high-voltage AC busbar in the medium-high voltage AC networking layer is 1.5kV～90kV, and the voltage level of the medium-low voltage DC busbar in the medium-low voltage DC networking layer 5V ~ 1.5kV.

Example 2

The invention proposes a multi-port DC power exchanger suitable for future medium and high voltage DC power distribution networks, and an AC-DC seamless fully controllable and flexible power distribution system centered on the DC power exchanger. Under the framework of the flexible power distribution system, the system management is unified by the flexible power distribution series equipment for grid-connected control, energy management, and coordinated operation.

(1) Single node hierarchical networking model of fully controllable flexible power distribution system

As shown in Figure 2, it is a fully controllable flexible power distribution system single-node hierarchical networking model with DC multi-port power exchangers as the core power distribution equipment. The port types of DC power exchangers include: DC-AC-DC, DC-DC . The AC and DC interfaces at the output end include sub-interfaces of different voltage levels (AC110V~35kV, DC5V~65kV) and different functions (load interface, energy storage interface, distributed generation grid connection interface, charging pile interface, power supply interface). By concentrating the AC and DC ports on the DC multi-port power exchanger, the seamless connection of the AC and DC lines in the distribution network is realized, and the number of AC and DC converters is effectively reduced.

The AC interface can realize industrial frequency AC power consumption, AC distributed power supply and load access; on the one hand, the DC interface can complete the access of distributed energy storage system, electric vehicle grid connection, distributed wind power generation and DC load, and on the other hand It can realize the access of the lower layer power exchanger. The power exchanger realizes charging and discharging, power generation, and load management through its own intelligent control, and realizes the access of low-voltage distributed power supply, energy storage, electric vehicles, and loads through power conversion. Through the combination of different types of AC and DC interfaces, a flexible power distribution core equipment with mixed AC and DC is formed, and a flexible power distribution system is constructed as a system node.

(2) Hierarchical networking framework of fully controllable and flexible power distribution system

As shown in Figure 3, it is a fully controllable and flexible power distribution system constructed with DC multi-port power exchangers as the core power distribution equipment. The DC multi-port power exchanger is divided into two types: high-voltage and medium-low voltage (for the convenience of introducing the DC multi-port power exchanger, Figure 3 shows a system composed of 4 power The unit network can be a single machine or multiple machines, and the lines can also be equipped or combined according to the actual situation). Among them, the DC high-voltage input range of the high-voltage DC multi-port power exchanger is 1.5kV ~ 65kV; multiple high-voltage DC multi-port power exchangers (shown as 1# and 2# in the figure) in the high-voltage DC distribution line are interconnected to form a high-voltage DC group Network layer (1.5kV ~ 65kV). The voltage range of the output AC port of the HVDC multi-port power exchanger is 1kV～35kV, and the voltage range of the output medium voltage DC port is 400V～1.5kV; among them, the medium voltage DC ports are interconnected to form a medium voltage DC network layer (400V～1.5kV) . In addition to connecting distributed power generation, energy storage and loads in the medium-voltage networking layer, it is also used as the input of medium-low voltage DC multi-port power exchangers (as shown in the figure, low-voltage DC multi-port power exchangers 1# and 2# pass 400V~1.5kV MVDC networking layer interconnection). The voltage range of the output AC port of the medium and low voltage DC multi-port power exchanger is 110V-380V, and the voltage range of the output low-voltage DC port is 5V-400V; among them, the low-voltage DC ports are interconnected to form a low-voltage DC networking layer (5V-400V).

In terms of spatial scope, the high-voltage power exchanger controls the flexible supply of high-voltage AC and DC power in a wide area, and at the same time realizes high-voltage and large-capacity distributed power supply and high-voltage load consumption; while the medium and low-voltage power exchanger is based on its voltage level and capacity. The scope of jurisdiction decreases in turn; the power exchangers of the same voltage level form the corresponding level, and the level is realized under such a flexible power distribution system architecture. Figure 3 is a network diagram of two high-voltage and two medium-low voltage DC multi-port power exchangers as nodes. In the future power distribution system, a parallel peer-to-peer network of multiple node systems will be extended infinitely, so as to build a huge fully scalable control flexible power distribution system.

The internal power of the system is flexibly converted between AC and DC through the power electronics core module of the power exchanger, and the AC and DC power distribution of different voltage levels are "seamlessly" mixed and operated in a closed loop, which is different from the two independent power distribution of AC and DC in the past. Compared with the system, it has many advantages such as control, coordination, energy efficiency and economy. This kind of fully controllable and flexible distribution network with AC and DC seamless hybrid of hierarchical networking is a distribution pattern of hierarchy, full peering, strong connection, AC and DC seamless hybrid, regional autonomy and hierarchical coordination. The architecture combining distribution and centralization is more conducive to hierarchical control. It covers the collection of micro and small energy sources, the consumption of energy storage and loads, the interconnection of power distribution nodes, and the seamless mixing of wide-area AC and DC formed by networking. The flexible distribution network meets the needs of the development of the next generation distribution network.

(3) DC multi-port power exchanger structure

The DC multi-port power exchanger mainly includes: power electronic solid-state module, power interface module, monitoring module and energy storage module (optional), intelligent control module, communication module and information processing module (as shown in Figure 4). The core module is a power electronic solid-state module, which mainly includes: a power electronic solid-state module including a solid-state module controller, a power electronic switch tube, a protection and drive module, and a sensing module connected in sequence; the power interface module includes a high-voltage AC interface, a high-voltage DC interface, power frequency AC interface and medium voltage DC interface;

The DC multi-port power exchangers of different voltage levels realize the communication and information plug-and-play of the power exchangers in the AC and DC power distribution area and between different levels through the conversion of the communication protocol and the power interface module, forming a physical information model . . Through the conversion of various communication protocols and various information access interfaces, the power exchanger realizes the communication and information plug-and-play of power exchangers in the region and between different levels, and constitutes a physical information model to achieve centralized control and distributed control. combined.

In the power electronic solid-state module topology, the AC/DC or DC/AC converter selects one of the multi-level topology structures according to the voltage level, and the number of modules in the multi-level topology structure depends on the DC voltage or AC voltage level. The level topology includes single-arm topology of diode clamping (NPC), H-bridge cascade topology and modular multi-level MMC topology. The number of levels of the multi-level structure adopted is determined according to the voltage level in the application;

The single-arm topology of the diode-embedded NPC is actually selected according to the power level of the NPC single-arm or three-phase three-arm topology, and the corresponding intermediate high-frequency isolation transformer adopts a single-phase or three-phase structure; the H-bridge stage The H-bridge in the multi-level topology and modular multilevel MMC topology adopts single-phase or three-phase topology according to the power level, and the transformer adopts corresponding changes. specific:

The topology of the power electronic solid-state module of the DC multi-port power exchanger is shown in Figure 5, where (a) is the structural block diagram of the power electronic solid-state module of the DC multi-port power exchanger. The DC/AC converter can choose one of the multi-level topologies shown in Figure 5(b) according to the voltage level, and the number of modules in the multi-level structure depends on the DC voltage level. Among them, Figure 5(b) shows the single-leg topology of diode clamping (NPC). In actual situations, NPC single-leg or three-phase three-leg topology can be selected according to the power level, and the corresponding mid-high frequency isolation transformer adopts Single-phase or three-phase construction. In the same way, in the H-bridge cascaded (H-bridge cascaded) and modular multi-level (MMC) topologies shown in Figure 5(b), the H-bridge can also adopt single-phase or three-phase topologies according to the power level, and the transformer can also be Make changes accordingly.

The present invention provides a multi-port DC power exchanger suitable for future medium and high voltage DC power distribution networks, and an AC-DC seamless fully controllable and flexible power distribution system centered on the DC power exchanger. The DC power exchanger has a variety of topology variants to meet the requirements of the power consumption terminal for AC and DC voltage levels; through the organic combination of centralized control and distributed control, energy storage devices, distributed power sources, and customized users in the power distribution system can be realized. The flexible control of the electric energy between the AC and DC achieves the purpose of seamless mixing of AC and DC and efficient integration and utilization of various energy sources.

The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art can still modify or equivalently replace the specific embodiments of the present invention. , any modifications or equivalent replacements that do not deviate from the spirit and scope of the present invention are within the protection scope of the claims of the present invention pending application.

Claims (10)

1. the complete controllable flexible distribution system of a kind of alternating current-direct current based on direct current multiport electric energy exchanger, which is characterized in that described Distribution system is made of multiple single distribution node level network model interconnections, the single distribution node level networking mould Type includes direct current multiport electric energy exchanger and its load of different voltages grade, and the load includes all kinds of power units, divides Cloth power supply and energy storage etc., the direct current multiport electric energy exchanger of the different voltages grade are connected with each other；

It is real in a manner that the DC port of AC port and corresponding voltage grade is concentrated on direct current multiport electric energy exchanger In existing between high-low pressure alternating current-direct current power distribution network, between alternating current-direct current power distribution network and distributed generation resource, energy storage device and power unit, The two-way flow of energy and information data；AC/DC convertor in power distribution network is reduced by way of alternating current-direct current port simultaneously Quantity, realize a distribution port in alternating current-direct current seamless control.

2. the complete controllable flexible distribution system of alternating current-direct current as described in claim 1, which is characterized in that the different voltages grade Direct current multiport electric energy exchanger includes high voltage direct current multiport electric energy exchanger in, the exchange of low-voltage direct multiport electric energy Device；

The input side of the high voltage direct current multiport electric energy exchanger is realized by high voltage dc bus and interconnected, and then realizes electric energy High voltage direct current networking layer on the basis of exchanger；

High voltage direct current multiport electric energy exchanger outlet side realizes interconnection by middle pressure dc bus, is formed based on electric energy exchanger Middle straightening stream networking layer；

In, low-voltage direct multiport electric energy exchanger input side pass through mesolow dc bus realize interconnection, realize electric energy exchange Mesolow direct current networking layer on the basis of device；

Voltage bus in networking layer and mesolow direct current networking layer is exchanged by high voltage direct current networking layer, mesohigh to interconnect, and is formed The complete controllable flexible distribution system of the alternating current-direct current formed with electrical nodes based on direct current multiport electric energy exchanger.

3. the complete controllable flexible distribution system of alternating current-direct current as claimed in claim 2, which is characterized in that the high voltage direct current networking layer High voltage dc bus voltage class for 90kV~180kV, the voltage of the middle pressure dc bus of medium pressure direct current networking layer Grade is 1.5kV~90kV, and the voltage class of the low-voltage direct busbar of the low-voltage direct networking layer is 5V~1.5kV.

4. the complete controllable flexible distribution system of alternating current-direct current as claimed in claim 3, which is characterized in that the different voltages grade Direct current multiport electric energy exchanger includes the electric information layer being connected with each other and electrical physical layer；The electric information layer includes prison Survey module, intelligent control module, communication module and message processing module and management control system；The electrical physical layer packet Include power electronics solid state module and electric energy interface module；The intelligent control module is connect with the power electronics solid state module.

5. the complete controllable flexible distribution system of alternating current-direct current as claimed in claim 4, which is characterized in that the power electronics solid-state mould Block includes sequentially connected solid state module controller, electronic power switch pipe, protection and drive module and surveys sense module；The electricity Energy interface module includes high-voltage alternating interface, high voltage direct current interface, industrial frequency AC interface and middle straightening stream interface；

The direct current multiport electric energy exchanger of the different voltages grade is real by the conversion of communications protocol and electric energy interface module Show in alternating current-direct current distribution region, the plug and play of the communication of electric energy exchanger and information between different levels, form physical message mould Type.

6. the complete controllable flexible distribution system of alternating current-direct current as claimed in claim 5, which is characterized in that the different voltages grade The outlet side port type of direct current multiport electric energy exchanger includes：Alternating current-direct current port and DC port；The alternating current-direct current port Tap mouth including different voltages grade and different function；By alternating current-direct current port in the direct current multiterminal of different voltages grade The mode of mouth electric energy exchanger, realizes the seamless connection of ac and dc circuit in power distribution network；

High-voltage alternating interface voltage grade in the alternating current-direct current port is 120kV~500kV；Voltage of middle pressure exchange interface etc. Grade is 2kV~120kV；The voltage class of low-voltage alternating-current interface is below 400V.

The interface of the different function includes loading interfaces, energy storage interface, distributed power generation and network interface, charging pile interface and electricity Source interface.

7. the complete controllable flexible distribution system of alternating current-direct current as claimed in claim 5, which is characterized in that the power electronics solid-state mould AC/DC or DC/AC converters select one kind in more level topological structures, more level topology knots according to voltage class in block topology The quantity of module depends on DC voltage or alternating voltage grade in structure, and more level topological structures include diode clamping Single bridge arm topological, H bridges cascaded topology and modular multilevel topology；

The mono- bridge arms of NPC or three bridge arm of three-phase are selected according to power grade under single bridge arm topological actual conditions of the diode clamping Topology, corresponding intermediate medium-high frequency isolating transformer use single-phase or three-phase structure；How electric the H bridges cascaded topology and modularization be H bridges in flat MMC topologys are topological using single-phase or three-phase according to power grade, and transformer takes corresponding change.

8. a kind of distribution method using the complete controllable flexibly distribution system of the alternating current-direct current described in any one of claim 1-7, It is characterized in that, the method includes：

Step 1：Determine the complete controllable flexibly single distribution node level network model of distribution system；

Step 2：By the complete controllable spirit of multiple complete controllable single distribution node level network model composition alternating current-direct currents of flexibly distribution system Distribution system living.

9. distribution method as claimed in claim 8, which is characterized in that the step 1 includes：

The direct current multiport electric energy exchanger of different voltages grade is connected with each other composition individual node level network model；

It is low in that the direct current multiport electric energy exchanger of the different voltages grade includes high voltage direct current multiport electric energy exchanger Straightening stream multiport electric energy exchanger；

The input side of the high voltage direct current multiport electric energy exchanger is realized by high voltage dc bus and interconnected, and then realizes electric energy High voltage direct current networking layer on the basis of exchanger；

High voltage direct current multiport electric energy exchanger outlet side is realized by mesohigh dc bus and interconnected, and is formed and is exchanged based on electric energy The middle straightening stream networking layer of device；

Mesolow direct current multiport electric energy exchanger input side is realized by mesolow dc bus and interconnected, and realizes electric energy exchanger On the basis of low-voltage direct networking layer；

High voltage direct current networking layer, middle straightening stream networking layer and low-voltage direct networking layer are mutual by direct current multiport electric energy exchanger Connection forms the complete controllable flexible distribution system of the alternating current-direct current based on direct current multiport electric energy exchanger.

10. distribution method as claimed in claim 8, which is characterized in that in the step 2, by multiple single distribution node layers Secondary network model is connected with each other the complete controllable flexible distribution system of composition alternating current-direct current, by the way that AC port and different voltages grade is straight Flow port concentrates on the mode of the load-side of direct current multiport direct current energy exchanger, realize mesohigh DC distribution net be depressured to Alternating current-direct current load supplying, mesohigh DC distribution net and distributed generation resource, the energy in bidirectional flow of energy storage device；Alternating current-direct current simultaneously The mode of port reduces the quantity of AC/DC convertor in power distribution network, realizes the seamless control of alternating current-direct current in a distribution port System.