An energy router and control method based on multi-mode hierarchical management strategy

Abstract

The present invention provides an energy router and a control method based on a multi-mode hierarchical management strategy, and relates to the fields of energy routers, hierarchical control, and power sharing. First, in response to the multi-port requirements of wind energy, solar energy, energy storage, and utilization, the present invention proposes a nine-port energy router to improve the flexibility of renewable energy consumption and power supply. In addition, in order to reduce the volume of the energy router, a non-isolated AC / DC hybrid topology structure is constructed by embedding an integrated power electronic converter, thereby realizing the miniaturization of the energy router. In order to improve the utilization rate of renewable energy, it is proposed to perform distributed module control on the various components of the energy router to provide voltage and frequency support for the system and realize power sharing of distributed power sources. On this basis, a three-mode switch power exchange control is proposed to ensure global energy flow balance under complex conditions.

Description

Technical Field

[0001] The present invention relates to the fields of energy routers, hierarchical control and power sharing; in particular, to an energy router and a control method based on a multi-mode hierarchical management strategy. Background Art

[0002] In recent years, smart homes have been vigorously promoted for their safe, convenient, comfortable and environmentally friendly living concepts. With the development of the smart home trend and the improvement of home automation levels, the widespread use of appliances in smart homes has led to a sharp increase in residential energy consumption. According to statistics from the U.S. Energy Information Administration in 2020, the energy consumption of residential buildings has reached 22% of the total energy consumption, but the proportion of renewable energy in the total energy consumption of residential buildings is only 12%. With the rapid growth of the number of smart homes, it is difficult for fossil fuels to meet future energy needs.

[0003] In order to alleviate the above contradictions, many scholars have studied the home energy management of smart homes. Some scholars have considered the balance between energy saving and comfortable living experience and established a multi-objective hybrid nonlinear programming model for smart home energy saving. Some scholars have proposed a stochastic dynamic programming framework for optimal energy management of smart homes. Some scholars have developed a fuzzy-based heuristic optimization controller to reduce the power consumption of equipment. Some scholars have proposed an optimization scheme based on autonomous energy management to reduce peak load time. However, most of the existing research on smart home energy management focuses on optimization strategies rather than energy scheduling hardware devices. From the perspective of residential energy management, smart homes urgently need a hardware device called "energy router" to realize the distribution, storage, conversion and utilization of multiple energy sources.

[0004] The topology design of the energy router should be specifically designed in combination with the actual needs of smart homes. From the perspective of residential energy supply, the energy router realizes the integration of wind energy, solar energy and energy storage. By directly incorporating local renewable energy generation into the smart home energy network, the consumption of renewable energy can be improved. From the perspective of residential energy utilization, a variety of new appliances have emerged in smart homes, from small power sensors to high-voltage DC electric vehicle charging piles. In order to reduce the number of power adapters, multiple power converters can be configured in the energy router to enhance the flexibility of power supply. In view of the needs of the energy supply and utilization sides of smart homes, multi-port design is particularly important for the topology of energy routers. However, due to the multi-port design, the difficulty of voltage level conversion and electrical energy form is inevitably increased. The voltage conversion and energy conversion of traditional power supply systems rely on isolation transformers, and the existence of isolation transformers increases the volume of power supply equipment. Obviously, it is not conducive to smart homes with limited space. In view of the actual needs of wind energy, solar energy, storage and utilization in smart homes, the topology of energy routers should have the characteristics of multi-port and small volume.

[0005] In the case of variable load and intermittent renewable power sources, it is difficult for energy routers to achieve full autonomy without control strategies for energy fluctuations and power imbalance. To solve this problem, household appliances are scheduled according to different priorities, with demand response as the dominant factor. However, power scheduling based on appliances weakens the flexibility of use, making it difficult to achieve "plug and play" for residential users. Some scholars have studied some specific topologies. Storage in the DC network is regarded as a voltage source to adjust the bus voltage, and storage in the AC network is regarded as a current source to maintain the balance between supply and demand. However, when the storage device fails, this system is heavily dependent on energy storage and is prone to collapse. Therefore, a monitoring and management scheme is adopted, and the upper energy management system (EMS) issues power commands to the lower circuits through the communication network. By monitoring and managing the output power of distributed power sources, the system's dependence on energy storage is reduced. However, when the communication link fails, this control scheme will reduce the system redundancy. Therefore, in view of the shortcomings of the above methods, droop control can be used to adjust the voltage and frequency of the system. This control method is independent of the communication link and complex control algorithms, which facilitates the "plug and play" of loads and the expansion of distributed power sources. For a specific AC / DC hybrid microgrid, dual droop control achieves power sharing between the DC network and the AC network. Similarly, dual droop control can also be applied to the management of energy routers. But in fact, due to the fragile characteristics of the home power grid, when the load and power supply change, the energy router is more likely to have power imbalance, which will increase the complexity of system energy management. Adopting multi-mode management is a feasible strategy. Combined with the actual operation situation, the system controls the energy flow through multi-mode switching to achieve global power balance. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides an energy router and a control method based on a multi-mode hierarchical management strategy.

[0007] An energy router based on a multi-mode hierarchical management strategy comprises: a renewable energy input port, a load output interface, an energy storage bidirectional interface, a DC bus, an AC bus, a distributed power source DS bus, a two-stage interconnected converter IC1, and a two-stage interconnected converter IC2;

[0008] The renewable energy input port includes three parts: wind power input system, photovoltaic power input system, and DC distributed power supply;

[0009] The photovoltaic power generation input system is connected to the DC bus; the energy storage bidirectional interface is connected to the DC bus; the DC bus is connected to one end of the distributed power source DS bus through a two-stage interconnection converter IC2; the other end of the distributed power source DS bus is connected to one end of the AC bus through a two-stage interconnection converter IC1; the other end of the AC bus is connected to the wind power generation input system;

[0010] The wind power input system consists of a tower, a generator, a gear speed increaser, a pitch and yaw system, a blade, a coupling, an electronic control system, and a DC / AC converter a; one end of the tower is connected to one end of the generator; one end of the gear speed increaser is connected to the other end of the generator; the pitch and yaw system is connected to the blade as a control system for controlling the blade; one end of the blade is connected to the other end of the tower through a coupling; the other end of the blade is connected to one end of the DC / AC converter a; and the other end of the DC / AC converter a is connected to the AC bus;

[0011] The photovoltaic power generation input system consists of a photovoltaic module, a controller, an inverter, a battery, and a DC / DC converter a; one end of the photovoltaic module is connected to one end of the inverter, the other end of the inverter is connected to one end of the controller, the other end of the controller is connected to one end of the battery, the other end of the battery is connected to one end of the DC / DC converter a, and the other end of the DC / DC converter a is connected to the DC bus;

[0012] The DC distributed power source is composed of a dispatchable DC power source and a DC / DC converter c, wherein one end of the DC / DC converter c is connected to the dispatchable DC power source and the other end is connected to the DC bus;

[0013] The load output interface includes three-phase AC output, household DC output, low-voltage single-phase AC output, low-voltage DC output, high-voltage DC output, DC / AC converter b, DC / DC converter b;

[0014] The three-phase AC output interface is directly derived from the AC bus as the power supply for high-power three-phase appliances; the household DC output interface is directly output from the DC bus, and the low-voltage single-phase AC interface is obtained from the DC bus through the DC / AC converter b, which meets the power supply requirements of DC appliances and AC appliances respectively; in order to reduce the number of power adapters for sensor equipment, a low-voltage DC interface is configured from the DC bus through the DC / DC converter b; in addition, considering the increasing use of electric vehicles, a high-voltage DC interface is derived from the distributed power supply DS bus to power the DC charging pile;

[0015] The energy storage bidirectional interface is composed of a battery energy storage unit, BESU, and a DC / DC converter c; one end of the battery energy storage unit is connected to one end of the DC / DC converter c, and the other end of the DC / DC converter c is connected to the DC bus;

[0016] Since the power generation of the photovoltaic power generation input system and the wind power generation input system varies greatly, the battery energy storage unit in the energy storage bidirectional interface has four energy sharing working modes, as shown below:

[0017] Working mode 1: Both photovoltaic power generation and wind power generation are oversaturated; the power flows from photovoltaic power generation to DC / DC converter a, flows to the household DC output interface, part of it flows to the load interface, and the other part flows to the high-voltage DC output interface through the two-stage interconnected converter IC2, flows to the DC / DC converter c, and flows to the battery energy storage unit for energy storage; the power flows from wind power generation to DC / AC converter a, flows to the low-voltage single-phase AC output interface, part of it flows to the load interface, and the other part flows to the high-voltage DC output interface through the two-stage interconnected converter IC1, flows to the DC / DC converter c, and flows to the battery energy storage unit;

[0018] Working mode 2: Photovoltaic power generation is oversaturated, and wind power generation cannot meet the power supply demand; power flows from photovoltaic power generation to DC / DC converter a, flows to the household DC output interface, part of it flows to the load interface, and the other part flows to the high-voltage DC output interface through the two-stage interconnected converter IC2, flows to the DC / DC converter c, and flows to the battery energy storage unit for energy storage; power flows from wind power generation to DC / AC converter a, flows to the low-voltage single-phase AC output interface, and all flows to the load interface; power flows from the battery energy storage unit to the low-voltage single-phase AC output interface through the DC / AC converter c, and flows to the load interface;

[0019] Working mode 3: Photovoltaic power generation does not meet the power supply requirements, and wind power generation is oversaturated; power flows from photovoltaic power generation to DC / DC converter a, flows to the household DC output interface, and all flows to the load interface; power flows from wind power generation to DC / AC converter a, flows to the low-voltage single-phase AC output interface, part of it flows to the load interface, and the other part flows to the high-voltage DC output interface through the two-stage interconnected converter IC1 and flows to the battery energy storage unit; power flows from the battery energy storage unit to the household DC output interface through the DC / DC converter c and flows to the load interface;

[0020] Working mode 4: Both photovoltaic power generation and wind power generation do not meet the power supply demand; power flows from photovoltaic power generation to DC / DC converter a, flows to the household DC output interface, and all flows to the load interface; power flows from wind power generation to DC / AC converter a, flows to the low-voltage single-phase AC output interface, and all flows to the load interface; power flows from the energy storage battery through the DC / AC converter c to the household AC bus and flows to the load interface; power flows from the battery energy storage unit through the DC / DC converter c to the household DC output interface and flows to the load interface;

[0021] On the other hand, the present invention also provides a control method of an energy router based on a multi-mode hierarchical management strategy;

[0022] In order to realize the energy router function, the distributed module local power sharing control method is as follows:

[0023] As a part of the energy router, the controller in the photovoltaic power input system includes a controller hierarchical management strategy to realize the autonomous operation of the energy router; the controller hierarchical management strategy includes the first layer of distributed module control and the second layer of power dispatch control;

[0024] Distributed module control, including local power sharing LPS of distributed power supply and load output interface, overall power sharing GPS of AC / DC two-stage interconnected converters IC1 and IC2, and energy storage power sharing SPS of battery energy storage unit; realize power sharing between distributed power supplies and provide voltage and frequency regulation;

[0025] Step 1: The distributed module controls the wind power input system;

[0026] The droop control is applied to the wind power input system to adjust the AC frequency and PF, QE droop characteristics; the specific formula is as follows:

[0027]

[0028]

[0029] Where f* refers to the reference frequency, E* refers to the reference voltage; P wind_x , Qwind_x Respectively refer to the active output and reactive output of the Xth wind turbine, m x Refers to the droop coefficient of Pf control, n x Refers to the droop coefficient of QE control; f min and f max They represent the maximum and minimum allowable frequencies of the AC bus, respectively. max and E min Respectively represent the maximum allowable voltage and minimum allowable voltage of the AC bus;

[0030] Through this droop control method, multiple wind turbines input system group shares the active power of the AC grid, that is, the proportion of their maximum power capacity to the total demand on the AC side, as shown in the following formula:

[0031]

[0032] in, Indicates the rated power output by the x-th wind turbine; the wind turbine is the wind power input system;

[0033] Step 2: Control of DC distributed power supply by distributed modules;

[0034] According to active power dispatch, DC distributed power sources can be divided into dispatchable DC distributed power sources and non-dispatched DC distributed power sources; dispatchable DC distributed power sources adjust the DC bus voltage, and photovoltaic power generation input belongs to non-dispatched DC distributed power sources and is regarded as a negative power load; in order to improve the utilization rate of solar energy, photovoltaic power generation input adopts maximum power point tracking control MPPT; the control of dispatchable DC distributed power sources adopts PV droop control; for the nth DC distributed power source, the PV droop control equation can be expressed as follows:

[0035]

[0036] Among them, V * dc Indicates the standard reference voltage, P dc_y is the active power output by the yth DC DG, d y is the negative droop coefficient of PV droop control, V max and V min Respectively represent the maximum allowable voltage and minimum allowable voltage of the DC bus;

[0037] Due to the trade-off between power sharing accuracy and voltage regulation, poor nonlinear load sharing performance, and sharing accuracy sensitivity to line impedance; Equation 4 is optimized as follows:

[0038]

[0039] Among them, Z dc_yand i dc_y are the cable impedance and output current respectively; through the droop control method, multiple DC distributed power sources share the active power of the DC network according to Formula 6, that is, the proportion of their maximum power capacity to the total demand on the DC side:

[0040]

[0041] Step 3: The distributed module controls the load output interface;

[0042] The household AC port, household DC port and high-voltage DC port are directly led out from the AC bus, DC bus and DS bus respectively; the standard dual-loop buck control method is adopted to stabilize the voltage of the low-voltage DC port; the dual-loop single-phase inverter control method based on the PR regulator is adopted to achieve the sinusoidal wave voltage output of the low-voltage AC port;

[0043] Step 4: The overall power sharing control method of the distributed module control energy router is as follows:

[0044] By properly adjusting the power flow of the two-stage interconnected converter, the overall power sharing of the two-stage interconnected converters IC1 and IC2 on the entire AC and DC side is achieved; since the active power attenuation of the AC side network and the DC side network has different scales, the active power attenuation expressions of the DC side and the AC side are normalized; the normalized definition is as follows:

[0045]

[0046]

[0047] Where, Nf is the normalized AC bus frequency, NV dc is the normalized DC bus frequency, Nf and NV dc The value range of is:

[0048] -1≤N f≤1; -1≤NV dc ≤1 (9)

[0049] When Nf and NV dc When N f and NV are equal, it means that the distributed power sources on the DC side and the AC side can share the total load; in order to force dc Equal, N f and NV dc As the input of the PI controller in the inverter, and P ref As the output of the PI controller to control the transmission power, then, P ref It can be obtained by formula 10, then i d_ref It can be obtained from Equation 11, and then the standard droop equation in Equation 12 is used to determine Q ref and iq_ref :

[0050] P ref =(k p +k i / s)(Nf-NV dc ) (10)

[0051] i d_ref =2P ref / (3E) (11)

[0052] Q ref =(EE max ) / n x ;i q_ref =-2Q ref / (3E) (12)

[0053] Among them, k p and k i is the PI controller gain, E is the voltage amplitude induced on the AC bus; P ref >0 means the DC bus supplies power to the AC bus, P ref <0 means the AC bus supplies power to the DC bus; i d_ref Indicates the rated active power current on the DC bus; Q ref represents the rated reactive power; s represents the parameter in Laplace transform;

[0054] If there is no power exchange from the battery energy storage unit, Equation 3 and Equation 6 can be expressed as:

[0055]

[0056] Among them, u refers to the total number of u wind power generation system inputs, and v refers to the total number of v dispatchable DC distributed power supply inputs;

[0057] IC2 is the energy transmission channel between the DC bus and the DS bus; IC2 uses dual-loop control to stabilize the voltage of the DS bus;

[0058] Step 5: The distributed module controls the battery energy storage unit as follows:

[0059] When the power supply system, i.e. the renewable energy input port, is severely overloaded / underloaded, the standard values ​​of the DC bus voltages Nvdc and Nf will decrease or increase, affecting the power supply quality of the energy router. The average load index σ is introduced to evaluate the system load, which is defined as:

[0060]

[0061] The local power sharing between the distributed power source and the load output port, i.e., the DC voltage and AC frequency in the distributed module second-layer control system working mode, is the same. It is inferred that the index σ in the renewable energy input port plays the same role in ensuring the SPS, i.e., the second-layer control system working mode, as in the following droop equation:

[0062]

[0063] Among them, P ds is the transmission power of the battery energy storage unit; P max dis is the maximum permissible transmission power of the battery energy storage unit; b z is the droop coefficient; when P ds >0, it means that the energy storage battery releases energy; when P ds When <0, it means that the energy storage battery absorbs energy;

[0064] Step 6: The second layer of power dispatching of controller hierarchical management strategy controls the energy router;

[0065] In any case, the operation state of all modules of the energy router is activated, which has the following two disadvantages:

[0066] A: The continuous energy transmission between the AC side, DC side and battery energy storage unit undoubtedly increases power transmission loss and reduces energy utilization;

[0067] B: Frequent charging and discharging will reduce the service life of the battery energy storage unit and increase management and maintenance costs;

[0068] In order to overcome the above shortcomings and limit the energy storage of unnecessary battery energy storage units, the power sharing second-layer control system working mode and the SPS second-layer control system working mode are operated; the range of thresholds θ1 and θ2 is given, and the normalized frequency N is introduced f and the normalized DC bus voltage N Vdc To evaluate the operating status of the energy router; by monitoring the changes in the DC bus voltage and AC bus frequency, trigger events can occur in the energy router system; according to the detected trigger events, the energy router is divided into three modes: Mode 1, Mode 2 and Mode 3; in the three modes, the operation of the energy router is as follows:

[0069] Mode 1: Local power sharing between distributed power sources and load output ports: The DC bus voltage and AC bus reference frequency are close to the corresponding reference values, indicating that the AC and DC side loads are operating close to ideal conditions. In order to avoid losses caused by AC and DC bus energy transmission, energy storage power sharing between SPS and battery energy storage units is prohibited.

[0070] Mode 2 local power sharing + global power sharing: the DC bus voltage and AC bus frequency have at least one large deviation from the reference value; in order to reduce the impact of power imbalance on system performance, it is necessary to activate energy transmission between the AC bus and the DC bus to achieve global power sharing of distributed generation; there are two specific situations: when the load on the AC side is lighter and the load on the DC side is heavier than the AC side, the AC side needs to transmit power to the DC side; when the load on the AC side is larger and the load on the DC side is lighter than the AC side, the DC side needs to transmit power to the AC side; so at this time, the energy storage power sharing of the battery energy storage unit needs to be started;

[0071] Mode 3: Local power sharing + overall power sharing + battery energy storage unit energy storage power sharing: When the DC bus voltage or AC bus frequency deviates greatly from the reference value, the energy router operates under severe light load or heavy load conditions; in order to prevent the system from collapsing, it is necessary to connect the power transmission between the AC bus and the DC bus to achieve power sharing, and it is also necessary to connect the battery energy storage unit to suppress further deterioration of the system; in severe light load conditions, the battery energy storage unit absorbs excess power; on the contrary, in severe heavy load conditions, the battery energy storage unit provides energy for the system; at this time, the battery energy storage unit energy storage power sharing and SPS are activated at the same time;

[0072] Through the above analysis of the controller hierarchical management strategy, the overall structure of the energy router hierarchical control is obtained; thereby realizing the control of an energy router based on a multi-mode hierarchical management strategy.

[0073] Beneficial technical effects of the present invention:

[0074] The energy router device for smart home proposed in the present invention can provide plug-and-play electric energy. The device realizes voltage conversion and energy transfer in the power system through power electronic conversion technology. It has the characteristics of high energy utilization, multi-port energy, small size, etc. It not only has the functions of converting voltage and transferring energy, but also has multiple functions such as improving power quality and providing standardized interfaces for various devices.

[0075] The present invention eliminates the power imbalance caused by source and load fluctuations and proposes a multi-mode switching hierarchical management control strategy. In the first layer system, a distributed module control is proposed to realize power sharing output and provide voltage and frequency regulation, and in the second layer system, a multi-mode switching power exchange control is proposed to realize the energy flow of the global energy balance control system.

[0076] The multi-port energy router for smart home proposed in the present invention can fully meet the household electricity needs. In view of the multi-port and low-capacity requirements, a nine-port energy router is designed. Among them, the four ports of solar and wind energy storage are used to improve the consumption of renewable energy in smart homes, and five voltage-level output ports are configured to improve the flexibility of the power supply system. On this basis, a non-isolated AC / DC hybrid topology embedded power electronic converter is designed to realize the miniaturization and integration of energy routers in smart homes. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] Figure 1 It is the main circuit topology diagram of the present invention;

[0078] Figure 2 Schematic diagram of the hierarchical management strategy adopted by the present invention;

[0079] Figure 3 The power dispatching control (second level control) of the present invention;

[0080] Figure 4 The present invention provides a control method for wind turbines in the local power sharing (second-layer control system working mode) of distributed power sources and output ports;

[0081] Figure 5 The present invention provides a control method for photovoltaic power generation in local power sharing (second-layer control system working mode) of distributed power sources and output ports;

[0082] Figure 6 The present invention provides a method for controlling household AC output;

[0083] Figure 7 The present invention provides a method for controlling household DC output;

[0084] Figure 8 The present invention provides a control method for IC2 part in the energy storage power sharing (second-layer control system working mode) of the battery energy storage unit;

[0085] Fig. 9 The present invention provides a control method for the IC1 part in the energy storage power sharing (second-layer control system working mode) of the battery energy storage unit;

[0086] Fig.10 This is a schematic diagram of the second-layer working mode system of the energy router of the present invention;

[0087] Fig.11 The present invention provides a control method for a battery energy storage unit. DETAILED DESCRIPTION

[0088] The present invention will be further described below in conjunction with the accompanying drawings and embodiments;

[0089] The present invention provides an energy router and a control method based on a multi-mode hierarchical management strategy.

[0090] The core function of this device is to convert the electric energy of different voltage levels output by different distributed power sources into electric energy of voltage levels suitable for electrical appliances, and realize power sharing. As a compatible interface for different energy switches, one end of this device is connected to different energy subnets within the distributed power source, and the other end is connected to household appliances to provide them with plug-and-play electric energy. This device realizes voltage conversion and energy transfer in the power system through power electronic conversion technology. Compared with traditional transformers, it has the advantages of small size, high energy utilization rate, and small size. It not only has the function of converting voltage and transferring energy, but also can realize power sharing of distributed power sources. And because of the use of three-mode switch power exchange control, the global energy flow balance under complex conditions is guaranteed.

[0091] An energy router based on a multi-mode hierarchical management strategy comprises: a renewable energy input port, a load output interface, an energy storage bidirectional interface, a DC bus, an AC bus, a distributed power source DS bus, a two-stage interconnected converter IC1, and a two-stage interconnected converter IC2; as shown in the attached Figure 1 As shown;

[0092] The renewable energy input port includes three parts: wind power input system, photovoltaic power input system, and DC distributed power supply;

[0093] The photovoltaic power generation input system is connected to the DC bus; the energy storage bidirectional interface is connected to the DC bus; the DC bus is connected to one end of the DS bus through a two-stage interconnected converter IC2; the other end of the DS bus is connected to one end of the AC bus through a two-stage interconnected converter IC1; the other end of the AC bus is connected to the wind power generation input system;

[0094] The wind power input system consists of a tower, a generator, a gear speed increaser, a pitch and yaw system, a blade, a coupling, an electronic control system, and a DC / AC converter a; one end of the tower is connected to one end of the generator; one end of the gear speed increaser is connected to the other end of the generator; the pitch and yaw system is connected to the blade as a control system for controlling the blade; one end of the blade is connected to the other end of the tower through a coupling; the other end of the blade is connected to one end of the DC / AC converter a; and the other end of the DC / AC converter a is connected to the AC bus;

[0095] The photovoltaic power generation input system consists of a photovoltaic module, a controller, an inverter, a battery, and a DC / DC converter a; one end of the photovoltaic module is connected to one end of the inverter, the other end of the inverter is connected to one end of the controller, the other end of the controller is connected to one end of the battery, the other end of the battery is connected to one end of the DC / DC converter a, and the other end of the DC / DC converter a is connected to the DC bus;

[0096] The DC distributed power source is composed of a dispatchable DC power source and a DC / DC converter c, wherein one end of the DC / DC converter c is connected to the dispatchable DC power source and the other end is connected to the DC bus;

[0097] The energy router is configured with 5 output circuit interfaces in accordance with the voltage standard of ANSI c84-la-1980 and the actual power supply requirements of smart homes. The load output interfaces include three-phase AC output, household DC output, low-voltage single-phase AC output, low-voltage DC output, high-voltage DC output, DC / AC converter b, and DC / DC converter b;

[0098] The three-phase AC output interface is directly derived from the AC bus as the power supply for high-power three-phase appliances; the household DC output interface is directly output from the DC bus, and the low-voltage single-phase AC interface is obtained from the DC bus through the DC / AC converter b, which meets the power supply requirements of DC appliances and AC appliances respectively; in order to reduce the number of power adapters for sensor equipment, a low-voltage DC interface is configured from the DC bus through the DC / DC converter b; in addition, considering the increasing use of electric vehicles, a high-voltage DC interface is derived from the distributed power supply DS bus to power the DC charging pile;

[0099] The energy storage bidirectional interface is composed of a battery energy storage unit, BESU, and a DC / DC converter c. One end of the battery energy storage unit is connected to one end of the DC / DC converter c, and the other end of the DC / DC converter c is connected to the DC bus. As an indispensable part of the energy router system, the battery energy storage unit charging and discharging can smooth the system energy fluctuations caused by sudden changes in load and power supply. On the other hand, when renewable energy is insufficient, it supports the system voltage and frequency.

[0100] Based on the large variation in power generation between the photovoltaic power generation input system and the wind power generation input system, the battery energy storage unit in the energy storage bidirectional interface has four energy sharing working modes, as shown below:

[0101] Working mode 1: Both photovoltaic power generation and wind power generation are oversaturated; the power flows from photovoltaic power generation to DC / DC converter a, flows to the household DC output interface, part of it flows to the load interface, and the other part flows to the high-voltage DC output interface through the two-stage interconnected converter IC2, flows to the DC / DC converter c, and flows to the battery energy storage unit for energy storage; the power flows from wind power generation to DC / AC converter a, flows to the low-voltage single-phase AC output interface, part of it flows to the load interface, and the other part flows to the high-voltage DC output interface through the two-stage interconnected converter IC1, flows to the DC / DC converter c, and flows to the battery energy storage unit;

[0102] Working mode 2: Photovoltaic power generation is oversaturated, and wind power generation cannot meet the power supply demand; power flows from photovoltaic power generation to DC / DC converter a, flows to the household DC output interface, part of it flows to the load interface, and the other part flows to the high-voltage DC output interface through the two-stage interconnected converter IC2, flows to the DC / DC converter c, and flows to the battery energy storage unit for energy storage; power flows from wind power generation to DC / AC converter a, flows to the low-voltage single-phase AC output interface, and all flows to the load interface; power flows from the battery energy storage unit to the low-voltage single-phase AC output interface through the DC / AC converter c, and flows to the load interface;

[0103] Working mode 3: Photovoltaic power generation does not meet the power supply requirements, and wind power generation is oversaturated; power flows from photovoltaic power generation to DC / DC converter a, flows to the household DC output interface, and all flows to the load interface; power flows from wind power generation to DC / AC converter a, flows to the low-voltage single-phase AC output interface, part of it flows to the load interface, and the other part flows to the high-voltage DC output interface through the two-stage interconnected converter IC1 and flows to the battery energy storage unit; power flows from the battery energy storage unit to the household DC output interface through the DC / DC converter c and flows to the load interface;

[0104] Working mode 4: Both photovoltaic power generation and wind power generation do not meet the power supply demand; power flows from photovoltaic power generation to DC / DC converter a, flows to the household DC output interface, and all flows to the load interface; power flows from wind power generation to DC / AC converter a, flows to the low-voltage single-phase AC output interface, and all flows to the load interface; power flows from the energy storage battery through the DC / AC converter c to the household AC bus and flows to the load interface; power flows from the battery energy storage unit through the DC / DC converter c to the household DC output interface and flows to the load interface;

[0105] According to the configuration of the energy router, the main circuit design of the power topology is as follows: Figure 2 As shown. This power supply topology realizes the integration of wind energy, solar energy, energy storage and utilization, and improves the penetration rate of renewable energy. The isolation transformer is abandoned in the main power circuit, and the conversion of voltage level and electric energy form is realized through the power electronic converter. The integrated full-power electronic circuit helps to realize the modularization and miniaturization of the energy router.

[0106] On the other hand, the present invention also provides a control method for an energy router based on a multi-mode hierarchical management strategy; Figure 2 As shown;

[0107] In order to realize the energy router function, the distributed module local power sharing control method is as follows:

[0108] The controller in the photovoltaic power generation input system is a part of the energy router, which includes a controller hierarchical management strategy to realize the autonomous operation of the energy router; the controller hierarchical management strategy includes the first layer of distributed module control and the second layer of power dispatching control; the second layer of power dispatching control is as shown in the attached Figure 3 As shown;

[0109] Input Vdc and Vdc_ref as parameters into equation 8 to obtain N Vdc, and use a partial result of the result through a computer algorithm to obtain Switch1. abc f obtained through the phase-locked loop ac , θ, and E are substituted into the first layer of control to perform the next part of the calculation.

[0110] Distributed module control, including local power sharing of distributed power sources and load output interfaces, overall power sharing of two-stage AC / DC interconnected converters IC1 and IC2, and energy storage power sharing of battery energy storage units; realize power sharing between distributed power sources and provide voltage and frequency regulation;

[0111] Step 1: The distributed module controls the wind power input system;

[0112] The droop control is applied to the wind power input system to adjust the AC frequency and PF, QE droop characteristics; the specific formula is as follows:

[0113]

[0114]

[0115] Where f* refers to the reference frequency, E* refers to the reference voltage; P wind_x , Q wind_x Respectively refer to the active output and reactive output of the Xth wind turbine, m x Refers to the droop coefficient of Pf control, n x Refers to the droop coefficient of QE control; f min and f max They represent the maximum and minimum allowable frequencies of the AC bus, respectively. max and E min Respectively represent the maximum allowable voltage and minimum allowable voltage of the AC bus;

[0116] Through this droop control method, multiple wind turbines input system group shares the active power of the AC grid, that is, the proportion of their maximum power capacity to the total demand on the AC side, as shown in the following formula:

[0117]

[0118] in, Indicates the rated power output of the xth wind turbine; the wind turbine is the wind power input system; as shown in the attached Figure 4 As shown;

[0119] Vabc and iabc are input as parameters into the P&Q controller, where the results of Pf droop control and PE droop control are input into the three-dimensional vector space again, the result is subtracted from Vabc and input into the voltage controller as a parameter. The signal obtained by the voltage controller is subtracted from iI_abc, and the result is input into the current controller to obtain a PWM signal to control Gac1 and Gac6.

[0120] Step 2: Control of DC distributed power supply by distributed modules;

[0121] According to active power dispatch, DC distributed power sources can be divided into dispatchable DC distributed power sources and non-dispatched DC distributed power sources; dispatchable DC distributed power sources adjust the DC bus voltage, and photovoltaic power generation input belongs to non-dispatched DC distributed power sources and is regarded as a negative power load; in order to improve the utilization rate of solar energy, photovoltaic power generation input adopts maximum power point tracking control MPPT. The specific control method is as shown in the attached Figure 5 As shown;

[0122] VPV and iPV are input as parameters into the maximum power point tracking control, and the result is subtracted from iPVL and input into the current controller to obtain a PWM signal to control GPV.

[0123] The control of dispatchable DC distributed power sources adopts PV droop control; for the nth DC distributed power source, the PV droop control equation can be expressed as follows:

[0124]

[0125] Among them, V * dc Indicates the standard reference voltage, P dc_y is the active power output by the yth DC DG, d y is the negative droop coefficient of PV droop control, V max and V min Respectively represent the maximum allowable voltage and minimum allowable voltage of the DC bus;

[0126] Due to the trade-off between power sharing accuracy and voltage regulation, poor nonlinear load sharing performance, and sharing accuracy sensitivity to line impedance; Equation 4 is optimized as follows:

[0127]

[0128] Among them, Z dc_y and i dc_yare the cable impedance and output current respectively; through the droop control method, multiple DC distributed power sources share the active power of the DC network according to Formula 6, that is, the proportion of their maximum power capacity to the total demand on the DC side:

[0129]

[0130] Step 3: The distributed module controls the load output interface;

[0131] The household AC port, household DC port and high-voltage DC port are directly led out from the AC bus, DC bus and DS bus respectively; the standard dual-loop buck control method is adopted to stabilize the voltage of the low-voltage DC port; the dual-loop single-phase inverter control method based on the PR regulator is adopted to achieve the sinusoidal wave voltage output of the low-voltage AC port;

[0132] The control method of the household AC output of the present invention is as shown in the attached Figure 6 As shown;

[0133] Vifac is subtracted from Vifac_ref and input into the proportional resonant controller as a parameter. iifac is subtracted from the output of the proportional resonant controller and input into the current controller. The current controller result is used as a PWM signal to control Gifac1 and Gifac4.

[0134] The control method of the household DC output of the present invention is as shown in the attached Figure 7 As shown;

[0135] Subtract Vifdc from Vifdc_ref and input it as a parameter to the voltage controller, subtract iifdc from the voltage controller output result and input it to the current controller, and use the current controller result as a PWM signal to control Gifdc.

[0136] Step 4: The overall power sharing control method of the distributed module control energy router is as follows:

[0137] By properly adjusting the power flow of the two-stage interconnected converter, the overall power sharing of the two-stage interconnected converters IC1 and IC2 on the entire AC and DC side is achieved; since the active power attenuation of the AC side network and the DC side network has different scales, the active power attenuation expressions of the DC side and the AC side are normalized; the normalized definition is as follows:

[0138]

[0139]

[0140] Where, Nf is the normalized AC bus frequency, NV dc is the normalized DC bus frequency, Nf and NVdc The value range of is:

[0141] -1≤N f≤1; -1≤NV dc ≤1 (9)

[0142] When Nf and NV dc When N f and NV are equal, it means that the distributed power sources on the DC side and the AC side can share the total load; in order to force dc Equal, N f and NV dc As the input of the PI controller in the inverter, and P ref As the output of the PI controller to control the transmission power, then, P ref It can be obtained by formula 10, then i d_ref It can be obtained from Equation 11, and then the standard droop equation in Equation 12 is used to determine Q ref and i q_ref :

[0143] P ref =(k p +k i / s)(Nf-NV dc ) (10)

[0144] i d_ref =2P ref / (3E) (11)

[0145] Q ref =(EE max ) / n x ;i q_ref =-2Q ref / (3E) (12)

[0146] Among them, k p and k i is the PI controller gain, E is the voltage amplitude induced on the AC bus; P ref >0 means the DC bus supplies power to the AC bus, P ref <0 means the AC bus supplies power to the DC bus; i d_ref Indicates the rated active power current on the DC bus; Q ref represents the rated reactive power; s represents the parameter in Laplace transform;

[0147] If there is no power exchange from the battery energy storage unit, Equation 3 and Equation 6 can be expressed as:

[0148]

[0149] Among them, u refers to the total number of u wind power generation system inputs, and v refers to the total number of v dispatchable DC distributed power supply inputs;

[0150] IC2 is the energy transmission channel between the DC bus and the DS bus. Its specific control algorithm is as shown in the attached Figure 8 Shown

[0151] The result of subtracting Vdc_ref from Vdc is input as a parameter into the voltage controller, and then the voltage comparator result is subtracted from iIC2 and the result is input into the current controller and used as a PWM signal to control GIC2_1 and GIC2_2.

[0152] IC2 uses dual-loop control to stabilize the voltage of the ds bus; its specific control algorithm is shown in the attached Fig. 9 As shown;

[0153] Input E and Emax into formula 2 to obtain iq_ref. If iq_ref is 0, switch Switch1 is closed. If iq_ref is not 0, switch Switch1 is opened. Input Nf and NVdc into the PI controller at the same time. Through formula 3, id_ref is obtained. If id_ref is 0, switch Switch1 is closed. If id_ref is not 0, switch Switch2 is opened. Subtract the signals obtained by the two current comparators from iIC1abc transformed into dq coordinates. The result is used as the current controller parameter to output PWM signal to control GIC_1 and GIC_6.

[0154] Step 5: The distributed module controls the battery energy storage unit as follows:

[0155] When the power supply system, i.e. the renewable energy input port, is severely overloaded / underloaded, the standard values ​​of the DC bus voltages Nvdc and Nf will decrease or increase, affecting the power supply quality of the energy router. The average load index σ is introduced to evaluate the system load, which is defined as:

[0156]

[0157] The local power sharing between the distributed power source and the load output port, i.e., the DC voltage and AC frequency in the distributed module second-layer control system working mode, is the same. It is inferred that the index σ in the renewable energy input port plays the same role in ensuring the SPS, i.e., the second-layer control system working mode, as in the following droop equation:

[0158]

[0159] Among them, P ds is the transmission power of the battery energy storage unit; P max dis is the maximum permissible transmission power of the battery energy storage unit; bz is the droop coefficient; when P ds >0, it means that the energy storage battery releases energy; when P ds When <0, it means that the energy storage battery absorbs energy;

[0160] Step 6: The second layer of power dispatching of controller hierarchical management strategy controls the energy router;

[0161] Due to the uncertainty of residential load and energy changes, the situations faced by energy routers in actual operation are relatively complex, such as: heavy load on the DC side and light load on the AC side; light load on the DC side and heavy load on the AC side; heavy load on both AC and DC sides; light load on both AC and DC sides; normal on both AC and DC sides; in any case, the operation status of all modules of the energy router is activated, which will have the following two disadvantages:

[0162] A: The continuous energy transmission between the AC side, DC side and battery energy storage unit undoubtedly increases power transmission loss and reduces energy utilization;

[0163] B: Frequent charging and discharging will reduce the service life of the battery energy storage unit and increase management and maintenance costs;

[0164] In order to overcome the above shortcomings and limit the energy storage of unnecessary battery energy storage units, the power sharing second-layer control system working mode and the SPS second-layer control system working mode are operated; the range of thresholds θ1 and θ2 is given, and the normalized frequency N is introduced f and the normalized DC bus voltage N Vdc To evaluate the operating status of the energy router; by monitoring the changes in the DC bus voltage and AC bus frequency, trigger events can occur in the energy router system;

[0165]

[0166] Specific details are as attached Fig.10 As shown;

[0167] Where Nf is the normalized frequency and N Vdc is the normalized voltage.

[0168] According to the detected trigger events, the energy router is divided into three modes: Mode 1, Mode 2 and Mode 3. In the three modes, the operation of the energy router is as follows:

[0169] Mode 1: Local power sharing between distributed power sources and load output ports: The DC bus voltage and AC bus reference frequency are close to the corresponding reference values, indicating that the AC and DC side loads are operating close to ideal conditions. In order to avoid losses caused by AC and DC bus energy transmission, energy storage power sharing between SPS and battery energy storage units is prohibited.

[0170] Mode 2 local power sharing + global power sharing: the DC bus voltage and AC bus frequency have at least one large deviation from the reference value; in order to reduce the impact of power imbalance on system performance, it is necessary to activate energy transmission between the AC bus and the DC bus to achieve global power sharing of distributed generation; there are two specific situations: when the load on the AC side is lighter and the load on the DC side is heavier than the AC side, the AC side needs to transmit power to the DC side; when the load on the AC side is larger and the load on the DC side is lighter than the AC side, the DC side needs to transmit power to the AC side; so at this time, the energy storage power sharing of the battery energy storage unit needs to be started;

[0171] Mode 3 local power sharing + overall power sharing + battery energy storage unit energy storage power sharing: When the DC bus voltage or AC bus frequency deviates greatly from the reference value, the energy router operates under severe light load or heavy load conditions; in order to prevent the system from collapsing, it is necessary to connect the power transmission between the AC bus and the DC bus to achieve power sharing, and it is also necessary to connect the battery energy storage unit to suppress further deterioration of the system; in severe light load conditions, the battery energy storage unit absorbs excess power; on the contrary, in severe heavy load conditions, the battery energy storage unit provides energy for the system; at this time, the battery energy storage unit energy storage power sharing and SPS are activated at the same time; the specific control method is as follows Fig.11 As shown;

[0172] Through the above analysis of the two-layer management strategy, the overall structure of the hierarchical control of the energy router can be obtained; and the control of an energy router based on a multi-mode hierarchical management strategy can be realized.

Claims

1. An energy router based on a multi-mode hierarchical management strategy, characterized in that: Specifically include: Renewable energy input port, load output interface, energy storage bidirectional interface, DC bus, AC bus, distributed power supply DS bus, two-stage interconnection converter IC1, two-stage interconnection converter IC2; The renewable energy input port includes three parts: wind power input system, photovoltaic power input system, and DC distributed power supply; The photovoltaic power generation input system is connected to the DC bus; the energy storage bidirectional interface is connected to the DC bus; the DC bus is connected to one end of the distributed power source DS bus through a two-stage interconnection converter IC2; the other end of the distributed power source DS bus is connected to one end of the AC bus through a two-stage interconnection converter IC1; the other end of the AC bus is connected to the wind power generation input system; The load output interface includes three-phase AC output, household DC output, low-voltage single-phase AC output, low-voltage DC output, high-voltage DC output, DC / AC converter b, DC / DC converter b; The three-phase AC output interface is directly derived from the AC bus as the power supply for high-power three-phase appliances; the household DC output interface is directly output from the DC bus, and the low-voltage single-phase AC interface is obtained from the DC bus through the DC / AC converter b, which meets the power supply requirements of DC appliances and AC appliances respectively; in order to reduce the number of power adapters for sensor equipment, a low-voltage DC interface is configured from the DC bus through the DC / DC converter b; a high-voltage DC interface is derived from the distributed power supply DS bus to power the DC charging pile; The energy storage bidirectional interface is composed of a battery energy storage unit and a DC / DC converter c; one end of the battery energy storage unit is connected to one end of the DC / DC converter c, and the other end of the DC / DC converter c is connected to the DC bus; As a part of the energy router, the controller in the photovoltaic power input system includes a controller hierarchical management strategy to realize the autonomous operation of the energy router; the controller hierarchical management strategy includes the first layer of distributed module control and the second layer of power dispatch control; Distributed module control, including local power sharing LPS of distributed power supply and load output interface, overall power sharing GPS of AC / DC two-stage interconnected converters IC1 and IC2, and energy storage power sharing SPS of battery energy storage unit; realize power sharing between distributed power supplies and provide voltage and frequency regulation; By analyzing the hierarchical management strategy of the controller, the overall structure of the hierarchical control of the energy router is obtained; the control of an energy router based on a multi-mode hierarchical management strategy is realized.

2. The energy router based on multi-mode hierarchical management strategy according to claim 1, characterized in that: The wind power input system is composed of a tower, a generator, a gear speed increaser, a pitch and yaw system, a blade, a coupling, an electronic control system, and a DC / AC converter a; wherein one end of the tower is connected to one end of the generator; one end of the gear speed increaser is connected to the other end of the generator; the pitch and yaw system is connected to the blade as a control system for controlling the blade; one end of the blade is connected to the other end of the tower through a coupling; the other end of the blade is connected to one end of the DC / AC converter a; and the other end of the DC / AC converter a is connected to the AC bus; The photovoltaic power generation input system consists of a photovoltaic module, a controller, an inverter, a battery, and a DC / DC converter a; one end of the photovoltaic module is connected to one end of the inverter, the other end of the inverter is connected to one end of the controller, the other end of the controller is connected to one end of the battery, the other end of the battery is connected to one end of the DC / DC converter a, and the other end of the DC / DC converter a is connected to the DC bus; The DC distributed power supply consists of a dispatchable DC power supply and a DC / DC converter c, wherein one end of the DC / DC converter c is connected to the dispatchable DC power supply and the other end is connected to the DC bus.

3. The energy router based on multi-mode hierarchical management strategy according to claim 1, characterized in that: The battery energy storage unit in the energy storage bidirectional interface has four energy sharing working modes, as shown below: Working mode 1: Both photovoltaic power generation and wind power generation are oversaturated; the power flows from photovoltaic power generation to DC / DC converter a, flows to the household DC output interface, part of it flows to the load interface, and the other part flows to the high-voltage DC output interface through the two-stage interconnected converter IC2, flows to the DC / DC converter c, and flows to the battery energy storage unit for energy storage; the power flows from wind power generation to DC / AC converter a, flows to the low-voltage single-phase AC output interface, part of it flows to the load interface, and the other part flows to the high-voltage DC output interface through the two-stage interconnected converter IC1, flows to the DC / DC converter c, and flows to the battery energy storage unit; Working mode 2: Photovoltaic power generation is oversaturated, and wind power generation cannot meet the power supply demand; power flows from photovoltaic power generation to DC / DC converter a, flows to the household DC output interface, part of it flows to the load interface, and the other part flows to the high-voltage DC output interface through the two-stage interconnected converter IC2, flows to the DC / DC converter c, and flows to the battery energy storage unit for energy storage; power flows from wind power generation to DC / AC converter a, flows to the low-voltage single-phase AC output interface, and all flows to the load interface; power flows from the battery energy storage unit to the low-voltage single-phase AC output interface through the DC / AC converter c, and flows to the load interface; Working mode 3: Photovoltaic power generation does not meet the power supply requirements, and wind power generation is oversaturated; power flows from photovoltaic power generation to DC / DC converter a, flows to the household DC output interface, and all flows to the load interface; power flows from wind power generation to DC / AC converter a, flows to the low-voltage single-phase AC output interface, part of it flows to the load interface, and the other part flows to the high-voltage DC output interface through the two-stage interconnected converter IC1 and flows to the battery energy storage unit; power flows from the battery energy storage unit to the household DC output interface through the DC / DC converter c and flows to the load interface; Working mode 4: Both photovoltaic power generation and wind power generation do not meet the power supply demand; power flows from photovoltaic power generation to DC / DC converter a, flows to the household DC output interface, and all flows to the load interface; power flows from wind power generation to DC / AC converter a, flows to the low-voltage single-phase AC output interface, and all flows to the load interface; power flows from the energy storage battery through the DC / AC converter c to the household AC bus and flows to the load interface; power flows from the battery energy storage unit through the DC / DC converter c to the household DC output interface and flows to the load interface.

4. The control method of an energy router based on a multi-mode hierarchical management strategy according to claim 1 is characterized in that: The distributed module controls the wind power input system as follows: The droop control is applied to the wind power input system to adjust the AC frequency and PF, QE droop characteristics; the specific formula is as follows: f=f * +m x P wind_x , E=E * +n x Q wind_x , Where f* refers to the reference frequency, E* refers to the reference voltage; P wind_x , Q wind_x Respectively refer to the active output and reactive output of the Xth wind turbine, m x Refers to the droop coefficient of Pf control, n x Refers to the droop coefficient of QE control; f min and f max They represent the maximum and minimum allowable frequencies of the AC bus, respectively. max and E min Respectively represent the maximum allowable voltage and minimum allowable voltage of the AC bus; Through this droop control method, multiple wind turbines input system group shares the active power of the AC grid, that is, the proportion of their maximum power capacity to the total demand on the AC side, as shown in the following formula: in, It indicates the rated power output by the x-th wind turbine; the wind turbine is the wind power input system.

5. The control method of an energy router based on a multi-mode hierarchical management strategy according to claim 1 is characterized in that: The distributed module controls the DC distributed power supply as follows: According to active power dispatch, DC distributed power sources can be divided into dispatchable DC distributed power sources and non-dispatched DC distributed power sources; dispatchable DC distributed power sources adjust the DC bus voltage, and photovoltaic power generation input belongs to non-dispatched DC distributed power sources and is regarded as a negative power load; in order to improve the utilization rate of solar energy, photovoltaic power generation input adopts maximum power point tracking control MPPT; the control of dispatchable DC distributed power sources adopts PV droop control; for the nth DC distributed power source, the PV droop control equation can be expressed as follows: Among them, V * dc Indicates the standard reference voltage, P dc_y is the active power output by the yth DC DG, d y is the negative droop coefficient of PV droop control, V max and V min Respectively represent the maximum allowable voltage and minimum allowable voltage of the DC bus; Due to the trade-off between power sharing accuracy and voltage regulation, poor nonlinear load sharing performance, and sharing accuracy sensitivity to line impedance; Equation 4 is optimized as follows: Among them, Z dc_y and i dc_y are the cable impedance and output current respectively; through the droop control method, multiple DC distributed power sources share the active power of the DC network according to Formula 6, that is, the proportion of their maximum power capacity to the total demand on the DC side:

6. The control method of an energy router based on a multi-mode hierarchical management strategy according to claim 1 is characterized in that: The distributed module controls the load output interface as follows: The household AC port, household DC port and high-voltage DC port are directly led out from the AC bus, DC bus and DS bus respectively; the standard dual-loop step-down control method is adopted to stabilize the low-voltage DC port voltage; the dual-loop single-phase inverter control method based on the PR regulator is adopted to achieve the sinusoidal wave voltage output of the low-voltage AC port.

7. The control method of an energy router based on a multi-mode hierarchical management strategy according to claim 1 is characterized in that: The overall power sharing control method of the distributed module controlled energy router is as follows: By properly adjusting the power flow of the two-stage interconnected converter, the overall power sharing of the two-stage interconnected converters IC1 and IC2 on the entire AC and DC side is achieved; since the active power attenuation of the AC side network and the DC side network has different scales, the active power attenuation expressions of the DC side and the AC side are normalized; the normalized definition is as follows: Where Nf is the normalized AC bus frequency, NV dc is the normalized DC bus frequency, Nf and NV dc The value range of is: -1≤N f≤1;-1≤NV dc ≤1 (9) When Nf and NV dc When Nf and NV are equal, it means that the distributed power sources on the DC side and the AC side can share the total load; in order to force dc Equal, Nf and NV dc As the input of the PI controller in the inverter, and P ref As the output of the PI controller to control the transmission power, then, P ref It can be obtained by formula 10, then i d_ref It can be obtained from Equation 11, and then the standard droop equation in Equation 12 is used to determine Q ref and i q_ref : P ref =(k p +k i / s)(Nf-NV dc ) (10) and d_ref =2P ref / (3E) (11) Q ref =(EE max ) / n x ;i q_ref =-2Q ref / (3E) (12) Among them, k p and k i is the PI controller gain, E is the voltage amplitude induced on the AC bus; P ref >0 means the DC bus supplies power to the AC bus, P ref <0 means the AC bus supplies power to the DC bus; i d_ref Indicates the rated active power current on the DC bus; Q ref represents the rated reactive power; s represents the parameter in Laplace transform; If there is no power exchange from the battery energy storage unit, Equation 3 and Equation 6 can be expressed as: Among them, u refers to the total number of u wind power generation system inputs, and v refers to the total number of v dispatchable DC distributed power supply inputs; IC2 is the energy transmission channel between the DC bus and the DS bus; IC2 uses dual-loop control to stabilize the voltage of the DS bus.

8. The control method of an energy router based on a multi-mode hierarchical management strategy according to claim 1 is characterized in that: The distributed module controls the battery energy storage unit as follows: When the power supply system, i.e. the renewable energy input port, is severely overloaded / underloaded, the standard values ​​of the DC bus voltages Nvdc and Nf will decrease or increase, affecting the power supply quality of the energy router. The average load index σ is introduced to evaluate the system load, which is defined as: The local power sharing between the distributed power source and the load output port, i.e., the DC voltage and AC frequency in the distributed module second-layer control system working mode, is the same. It is inferred that the index σ in the renewable energy input port plays the same role in ensuring the SPS, i.e., the second-layer control system working mode, as in the following droop equation: Among them, P ds is the transmission power of the battery energy storage unit; Pmax dis is the maximum permissible transmission power of the battery energy storage unit; b z is the droop coefficient; when P ds >0, it means that the energy storage battery releases energy; when P ds When <0, it means that the energy storage battery absorbs energy.

9. The control method of an energy router based on a multi-mode hierarchical management strategy according to claim 1 is characterized in that: The second-level power dispatching of the controller hierarchical management strategy controls the energy router as follows: Power sharing second-layer control system working mode and SPS second-layer control system working mode operation; give the range of thresholds θ1 and θ2, and introduce the normalized frequency N f and the normalized DC bus voltage N Vdc To evaluate the operating status of the energy router; by monitoring the changes in the DC bus voltage and AC bus frequency, trigger events can occur in the energy router system; according to the detected trigger events, the energy router is divided into three modes: Mode 1, Mode 2 and Mode 3; in the three modes, the operation of the energy router is as follows: Mode 1: Local power sharing between distributed power sources and load output ports: The DC bus voltage and AC bus reference frequency are close to the corresponding reference values, indicating that the AC and DC side loads are operating close to ideal conditions. In order to avoid losses caused by AC and DC bus energy transmission, energy storage power sharing between SPS and battery energy storage units is prohibited. Mode 2 local power sharing + global power sharing: the DC bus voltage and AC bus frequency have at least one large deviation from the reference value; in order to reduce the impact of power imbalance on system performance, it is necessary to activate energy transmission between the AC bus and the DC bus to achieve global power sharing of distributed generation; there are two specific situations: when the load on the AC side is lighter and the load on the DC side is heavier than the AC side, the AC side needs to transmit power to the DC side; when the load on the AC side is larger and the load on the DC side is lighter than the AC side, the DC side needs to transmit power to the AC side; so at this time, the energy storage power sharing of the battery energy storage unit needs to be started; Mode 3: local power sharing + overall power sharing + energy storage power sharing of battery energy storage unit: when the DC bus voltage or AC bus frequency deviates greatly from the reference value, the energy router operates under severe light load or heavy load conditions; in order to prevent the system from collapsing, it is necessary to connect the power transmission between the AC bus and the DC bus to achieve power sharing, and it is also necessary to connect the battery energy storage unit to suppress further deterioration of the system; in severe light load conditions, the battery energy storage unit absorbs excess power; on the contrary, in severe heavy load conditions, the battery energy storage unit provides energy for the system; at this time, the energy storage power sharing of the battery energy storage unit and the SPS are activated at the same time.

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