WO2021012298A1 - 多端口能源路由器自-互-群多层次稳定辨识与回稳方法 - Google Patents

多端口能源路由器自-互-群多层次稳定辨识与回稳方法 Download PDF

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WO2021012298A1
WO2021012298A1 PCT/CN2019/098302 CN2019098302W WO2021012298A1 WO 2021012298 A1 WO2021012298 A1 WO 2021012298A1 CN 2019098302 W CN2019098302 W CN 2019098302W WO 2021012298 A1 WO2021012298 A1 WO 2021012298A1
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energy router
stability
energy
impedance
node
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PCT/CN2019/098302
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English (en)
French (fr)
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孙秋野
王睿
马大中
胡旌伟
孙振奥
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东北大学
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Priority to EP19915586.2A priority Critical patent/EP3817177B1/en
Publication of WO2021012298A1 publication Critical patent/WO2021012298A1/zh

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J1/00—Circuit arrangements for dc mains or dc distribution networks
    • H02J1/10—Parallel operation of dc sources
    • H02J1/106—Parallel operation of dc sources for load balancing, symmetrisation, or sharing
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F17/00—Digital computing or data processing equipment or methods, specially adapted for specific functions
    • G06F17/10—Complex mathematical operations
    • G06F17/11—Complex mathematical operations for solving equations, e.g. nonlinear equations, general mathematical optimization problems
    • G06F17/13—Differential equations
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
    • H02M1/007—Plural converter units in cascade
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
    • H02M1/008—Plural converter units for generating at two or more independent and non-parallel outputs, e.g. systems with plural point of load switching regulators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
    • H02M5/40—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc
    • H02M5/42—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters
    • H02M5/44—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac
    • H02M5/453—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M5/458—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M5/4585—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only having a rectifier with controlled elements
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • H02J2300/22—The renewable source being solar energy
    • H02J2300/24—The renewable source being solar energy of photovoltaic origin
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • H02J2300/28—The renewable source being wind energy
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/02—Circuit arrangements for ac mains or ac distribution networks using a single network for simultaneous distribution of power at different frequencies; using a single network for simultaneous distribution of ac power and of dc power
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381—Dispersed generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
    • H02M3/33573—Full-bridge at primary side of an isolation transformer
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/56—Power conversion systems, e.g. maximum power point trackers

Definitions

  • the present invention relates to the technical field of energy internet, in particular to a method for self-inter-group multi-level stability identification and stabilization of a multi-port energy router.
  • the energy router is a combination of power electronic technology and high-frequency transformer technology, and the method of combining power electronic converters and high-frequency isolation transformers makes the energy router have voltage sag compensation, power failure compensation, instantaneous voltage adjustment, and The advantages of fault isolation, reactive power compensation, harmonic isolation, new energy access, etc., and its small size and light weight are conducive to modular integration.
  • a single energy router includes a front-end DC converter, a two-way bridge converter, and a back-end AC/DC converter.
  • the instability phenomenon caused by the interaction of the three parts has attracted more and more attention.
  • the impedance stability analysis method is to divide the system into a stable power subsystem and a stable load subsystem, and to evaluate the stability of the entire system through the generalized Ness curve.
  • some researchers have put forward relevant discussions.
  • gain margin and phase angle margin criterion gain margin and phase angle margin criterion
  • Energy Source Analysis Consortium criterion Opposing The Argument criterion and the Three-Step Impedance criterion were successively proposed.
  • the inverse generalized Ness curve criterion In order to solve the shortcomings of the generalized Ness curve, the inverse generalized Ness curve criterion, Mikhailov criterion, etc. are proposed. In order to realize the stability analysis of the two-way flow system, the Sum Type criterion has been proposed. Other simplified stability criteria, such as G-norm stability criterion, singular value stability criterion, infinite-1 norm stability criterion and infinite norm stability criterion have been successively proposed. Therefore, the impedance-based stability analysis technology applied to the stability identification of energy routers has inherent advantages. M. Khazraei first proposed an energy router stability analysis method based on impedance stability analysis technology. However, the control strategy of the energy router sub-module is very special and difficult to implement in practical applications. Therefore, the stable identification of energy routers is still an open issue, and the multi-layer stabilization control of cluster energy router systems is also urgently needed.
  • the technical problem to be solved by the present invention is to address the above-mentioned shortcomings of the prior art, and provide a self-inter-group multi-level stability identification and stabilization method for a multi-port energy router to achieve stable identification and stabilization control of the energy router purpose.
  • the technical solution adopted by the present invention is: a multi-port energy router self-inter-group multi-level stability identification and stabilization method, including the following steps:
  • Step 1 Initialize the system parameters of the single dual energy flow multi-port energy router system to be tested; the system parameters include the front-end DC converter of the energy router system, the dual-active bridge bidirectional DC-DC converter, and the back-end AC/DC conversion The resistance value, inductance value, capacitance value, line impedance, switching frequency and multi-interface energy storage and photovoltaic equipment in the three subsystems of the generator;
  • Step 2 Construct the Eular-Lagrange mathematical model according to the topological structure of the front-end DC converter, and calculate its transfer function according to the mathematical model of the front-end DC converter, and then judge the stability of the DC front-end of the multi-port energy router system. If the judgment result is Instability, the multi-port energy router system is determined to be self-level instability, and step 7 is executed, otherwise, step 3 is executed;
  • Step 3 Construct its Eular-Lagrange mathematical model according to the topology of the dual active bridge bidirectional DC-DC converter, and calculate its transfer function according to the mathematical model of the dual active bridge bidirectional DC-DC converter, and then judge its stability ; If the judgment result is instability, the multi-port energy router system is judged to be self-level instability, go to step 7, otherwise go to step 4;
  • Step 4 Construct its Eular-Lagrange mathematical model according to the circuit topology of the back-end AC/DC converter, and calculate its transfer function according to the mathematical model of the back-end AC/DC converter, and determine it according to the Ness curve of the transfer function For the stability of the AC/DC converter at the end, if the judgment result is instability, the multi-port energy router system is judged to be self-level instability, and step 7 is executed, otherwise, step 5 is executed;
  • Step 5 After confirming that the basic three-level independent subsystem of the single dual energy flow multi-port energy router is stable through steps 2-4, connect multiple loads and photovoltaic, photovoltaic, and photovoltaic power to the front and rear bus bars of the dual active bridge bidirectional DC-DC converter.
  • the new energy equipment such as wind turbines further determines the stability of a single dual energy flow multi-port mutual coupling energy router;
  • Step 5.1 Connect n different devices in parallel at the front stage of the dual active bridge bidirectional DC-DC converter, including loads, energy storage, and other photovoltaic and wind turbine new energy equipment; at the same time, the independent stability of the load and photovoltaic installations is not considered; There are line impedances and the coupling effects of the input and output impedances of each device in parallel.
  • Each interface in the multi-port energy router system is regarded as a sub-module independently, and there are line impedances between every two interfaces, and the generalized bandwidth is used for small disturbance currents.
  • the injector equates the multi-interface circuit structure to the Thevenin circuit with mirror frequency coupling; the system stability is judged by constructing the overall system relationship function matrix extending from the interface to the surroundings and the closed-loop pole position of the system;
  • Step 5.1.1 Connect n devices in parallel at the bus bar of the front end of the DC converter, corresponding to n nodes, and set each node to have a power source and its own load and exist between the connecting lines of any two devices Line impedance, where the external output characteristics of the equipment are called the source equipment, and the external output characteristics are called the load equipment.
  • Step 5.1.2 Model the multi-port energy router multi-parallel system by using the matrix multi-point criterion (MFC) method;
  • Step 5.1.3 Use the method of matrix multi-point criterion to determine each node in K(s) Corresponding zeros and poles; express the relational function matrix as the "ratio" of two polynomial matrices, set N(s)D -1 (s) and A -1 (s)B(s) as the given relational functions respectively Any irreducible right MFC and left MFC of matrix K(s), where N(s) represents any irreducible right MFC molecular part of a given relation function matrix K(s), and D(s) represents a given relation Any irreducible right MFC denominator part of the function matrix K
  • V k Z loadk i loadk
  • V k -V j Z linckj i linckj
  • V j is the voltage at node j
  • the output current of the front-end DC circuit on node k is:
  • i ok Y eqk (G k V k -V k )
  • Z eqk is the line impedance between node k and node j
  • G k is the proportional coefficient
  • Is load admittance Z loadk is load impedance
  • G cli represents the current proportional coefficient
  • G clv represents the voltage proportional coefficient
  • K(s) It is the closed-loop relation function matrix K(s) of the energy router system.
  • Step 6 After determining the stability of the single dual energy flow multi-port energy router through step 5, determine the stability of the entire cluster energy router system;
  • Step 6.1 When the system is obtained by hybrid connection of m energy routers, use the generalized bandwidth small disturbance current injector to obtain the output impedance matrix of the cluster energy router system, and use the following formula to denoise the cluster energy router system to obtain the cluster energy router system
  • Step 6.2 According to the relevance of the admittance matrix and the stability characteristics of the system, when steps 1-5 determine that the self-level and mutual levels of the system are stable and the following formula does not have a right pole:
  • the cluster dual-energy flow multi-port energy router system is stable, otherwise, the cluster dual-energy flow multi-port energy router system is the energy router group level instability. Go to step 7 to reshape the three-layer impedance of the cluster energy router to make the system stable;
  • Step 7 If the cluster single-phase dual-energy flow multi-port energy router system has instability results through the above steps 2-6 identification, the self-adjusting parameter technology and passive coupling impedance are adopted for the different levels of instability links in steps 2-6 Remodeling technology and source-side cascaded impedance remodeling technology make the system stable;
  • Step 7.1 In view of the self-level instability of energy routers, according to the principle that the smaller the droop coefficient, the higher the system stability, the arctangent function is used to adjust the droop control coefficient in the back-end DC converter of a single energy router, as shown in the following formula Show, and re-execute step 1;
  • R represents the sag coefficient
  • R 0 represents the initial sag coefficient
  • k 1 and k 2 are the scale coefficients
  • ⁇ is the translation coefficient
  • Step 7.2 Aiming at the inter-level instability of energy routers, the power-side cascaded impedance control reduces the impedance of the power-side subsystem to meet the stability of the system;
  • the front-end DC converter or dual active bridge bidirectional DC-DC converter is equivalent It is a generalized rectifier, and its Eular-Largrange model is expressed as:
  • L n , R n , C d , Rd are the equivalent inductance and resistance of the front end of the generalized rectifier and the equivalent capacitance and resistance of the back end, respectively, and u dc , i d , and i q are the DC front-end voltage and dq axial current, u d , u q are the dq axial voltage on the output side of the rectifier respectively; S d and S q respectively represent the switching duty cycle in the dq coordinate system, and ⁇ represents the angular velocity of the multi-port energy router system;
  • the ideal state variable of the multi-port energy router system is expressed as:
  • u dc represents the DC side voltage of the multi-port energy router system
  • x ref is the ideal state variable
  • U m is the maximum output voltage of the generalized rectifier
  • R p represents the damping injection factor, which is a symmetric positive definite damping matrix, namely
  • r p1 -r p3 all represent virtual injection resistance
  • step 5 is executed again;
  • Step 7.3 In view of the instability phenomenon of the energy router group, the system is stabilized by increasing the output admittance matrix on the power supply side, that is, reducing the output impedance value in the Thevenin equivalent circuit.
  • the single energy router is stable, the cluster energy Since routers are coupled to each other, they will only induce low-frequency oscillation and synchronization instability, rather than instability in the entire frequency domain. Therefore, the designed virtual impedance is an impedance reshaping technology in a specific frequency domain.
  • the specific expression is shown in the following formula:
  • (f on -f lo , f on +f lo ) represents the instability frequency range
  • K represents the attenuation coefficient
  • Z vir represents the virtual impedance
  • f lo represents the lower frequency limit
  • f on represents the upper frequency limit
  • s represents the Laplace Multiplier
  • step 6 is performed again.
  • the self-inter-group multi-level stability identification and stabilization method of the multi-port energy router provided by the present invention fundamentally solves the problem of complex stability evaluation of the cluster energy router, and uses self
  • the hierarchical stability identification technology eliminates the assumptions of the stability of each sub-module of the traditional impedance technology, and then uses the mutual hierarchical stability identification technology to solve the coupling stability problem of the multi-level power conversion device, and finally uses the group-level stability identification technology to obtain a complex energy router network
  • the necessary and sufficient conditions for stability have effectively promoted the development of the Energy Internet.
  • FIG. 1 is a schematic structural diagram of a single dual energy flow multi-port energy router provided by an embodiment of the present invention
  • FIG. 2 is a flowchart of a self-inter-group multi-level stability identification and stabilization method for a multi-port energy router according to an embodiment of the present invention
  • FIG. 3 is a single dual energy flow multi-port energy router topology and control block diagram provided by an embodiment of the present invention
  • FIG. 5 is a schematic diagram of a multi-node energy router provided by an embodiment of the present invention.
  • Figure 6 is a multi-node equivalent circuit diagram of an energy router provided by an embodiment of the present invention.
  • FIG. 7 is an equivalent diagram of node k in an energy router provided by an embodiment of the present invention.
  • Figure 8 is a topology connection diagram of a cluster energy router provided by an embodiment of the present invention.
  • FIG. 9 is a block diagram of passive coupling impedance reshaping control provided by an embodiment of the present invention.
  • Fig. 10 is a block diagram of source-side cascaded impedance reshaping control provided by an embodiment of the present invention.
  • the multi-port energy router system shown in FIG. 1 adopts the multi-port energy router self-inter-group multi-level stability identification and stabilization method of the present invention to perform stability identification and stabilization;
  • the multi-port energy router The system includes voltage and current acquisition modules, impedance generation modules, communication modules, information processing modules, and three-layer impedance reshaping modules;
  • the three-layer impedance reshaping module adopts the three-layer impedance reshaping and stabilization control strategy of the present invention to ensure the overall stability of the system Sex.
  • the self-inter-group multi-level stability identification and stabilization method of a multi-port energy router includes the following steps:
  • Step 1 Initialize the system parameters of the single dual energy flow multi-port energy router system to be detected;
  • the system parameters include the front-end DC converter of the energy router system, and the dual active bridge bidirectional DC-DC converter (Dual Active Bridge, namely DAB) ), the resistance value, inductance value, capacitance value, line impedance, switching frequency and multi-interface energy storage and photovoltaic equipment in the three subsystems of the back-end AC/DC converter;
  • Step 2 Construct the Eular-Lagrange mathematical model according to the topological structure of the front-end DC converter, and calculate its transfer function according to the mathematical model of the front-end DC converter, and then judge the stability of the DC front-end of the multi-port energy router system. If the judgment result is Instability, the multi-port energy router system is determined to be self-level instability, and step 7 is executed, otherwise, step 3 is executed;
  • Step 2.1 Construct a mathematical model based on the front-end DC circuit in the single-phase dual-energy flow multi-port energy router topology and control block diagram shown in Figure 3, where C H is the DC side output capacitor, L r is the AC side input filter inductance, R r Is the equivalent resistance on the AC side, u g is the grid voltage, i g is the grid current, U H is the DC side voltage, D b is the droop coefficient, U n is the DC side rated voltage, C v is the introduced virtual capacitance, i REC Is the DC side current and i H the DC side output current, H is the current feedforward coefficient; the mathematical expression of the front-end DC circuit is as follows:
  • equation (1) can be expressed as follows:
  • Step 2.2 According to the front-end DC circuit control strategy in the single dual-energy flow multi-port energy router topology and control block diagram shown in Figure 3, the transfer function of the current inner loop can be expressed as follows:
  • equation (3) can be simplified as follows:
  • the small signal model is as follows:
  • G c (s) G i (s)/(G i (s)+(L r s+R r )+H),
  • G vir (s) -1/(D b +G v (s)U n s+H)
  • Step 2.3 According to the obtained front-end DC circuit transfer function, the data obtained after processing by DSP is passed to the upper computer through the SCI communication module, and then the number of right poles is judged by calculating the Ness curve. If the number is zero, the front-end If the DC circuit is stable, proceed to step 3. If the number is not zero, it is unstable, skip to step 7;
  • Step 3 Construct its Eular-Lagrange mathematical model according to the topology of the dual active bridge bidirectional DC-DC converter, and calculate its transfer function according to the mathematical model of the dual active bridge bidirectional DC-DC converter, and then judge its stability ; If the judgment result is instability, the multi-port energy router system is judged to be self-level instability, go to step 7, otherwise go to step 4;
  • Step 3.1 According to the power transmission control strategy of the dual active bridge bidirectional DC-DC converter, the DAB module and the power transmission control single-phase shift control strategy are obtained through Figure 3 to obtain the DAB structure power conversion; the dual active bridge converter is used as the energy source
  • the core module of voltage level conversion and electrical isolation in the router, the high-frequency transformer ratio is n:1
  • C H is the high-voltage side DC bus capacitor (this capacitor is the same capacitor as the front-end DC circuit-level DC bus capacitor)
  • C L is low voltage Side DC bus capacitor (this capacitor is the same capacitor as the back-end AC/DC circuit-level DC bus capacitor)
  • L T is the sum of the leakage inductance and auxiliary inductance of the high-frequency transformer
  • U H is the high-voltage side DC bus voltage
  • U L is the low-voltage
  • U 12 and U 34 are the high-frequency chopped voltage output by the H bridges on both sides of the DAB
  • i T is the primary side current of the high-frequency transformer
  • i L
  • Step 3.2 When the transformer ratio is about 1, the single-phase-shift control strategy has a smaller current stress than other phase-shift control strategies. At the same time, this control scheme is easier to implement.
  • Figure 4 shows the DAB in single-phase-shift control. Schematic diagram of the drive signal, voltage and current of the switch tube. By analyzing the transformer leakage current and the voltage across the transformer at each time, the DAB power transmission characteristics under single-phase-shift control can be obtained.
  • DAB high-voltage side power relationship is:
  • the load current changes, it will affect the DAB low-voltage side DC voltage regulation characteristics, in order to reduce or eliminate this effect, the load current is introduced into the feedforward control link in the controller.
  • the transfer function of the feedforward link can be written as follows:
  • F is the feedforward coefficient.
  • the data obtained after processing by DSP is passed to the host computer through the SCI communication module, and then the number of right poles is judged by calculating the Ness curve. If the number is zero, the DAB is stable, and then continue to execute Step 4. If the number is not zero, the judgment result is unstable and skip to step 7;
  • Step 4 Construct its Eular-Lagrange mathematical model according to the circuit topology of the back-end AC/DC converter, and calculate its transfer function according to the mathematical model of the back-end AC/DC converter, and determine it according to the Ness curve of the transfer function For the stability of the AC/DC converter at the end, if the judgment result is instability, the multi-port energy router system is judged to be self-level instability, and step 7 is executed, otherwise, step 5 is executed;
  • Step 4.1 Construct a mathematical model based on the actual back-end AC/DC circuit parameters.
  • the partial topological structure of the back-end AC circuit is shown in Figure 3.
  • the mathematical model of the inductor current of the DC/AC conversion stage in the rotating coordinate system can be expressed as:
  • the decoupled DC/AC conversion stage current inner loop controller model can be expressed as:
  • the voltage loop decoupling control is further simplified as:
  • the small signal transfer function can be expressed as follows:
  • the transfer function of the voltage outer loop can be expressed as:
  • Step 4.2 According to the obtained back-end AC/DC circuit transfer function, the data obtained after processing by the main control unit is transmitted to the upper computer through the SCI communication module, and then the number of right poles is judged by calculating the Ness curve. If the number is 0, then the back-end AC/DC circuit is stable, then continue to step 5. If the number is not zero, the judgment result is unstable and skip to step 7;
  • Step 5 After confirming that the basic three-level independent subsystem of the single dual energy flow multi-port energy router is stable through steps 2-4, connect multiple loads and photovoltaic, photovoltaic, and photovoltaic power to the front and rear bus bars of the dual active bridge bidirectional DC-DC converter.
  • the new energy equipment such as wind turbines further determines the stability of the single-phase dual energy flow multi-port mutual coupling energy router; due to the symmetry of the front and rear stages of the dual active bridge bidirectional DC-DC converter converter, the following is only stable for the front stage Give a detailed explanation of sex;
  • Step 5.1 Connect n different devices in parallel at the front stage of the dual active bridge bidirectional DC-DC converter, including loads, energy storage, and other photovoltaic and wind turbine new energy equipment; at the same time, the independent stability of the load and photovoltaic installations is not considered; There are line impedances and the coupling effects of the input and output impedances of each device in parallel.
  • Each interface in the multi-port energy router system is regarded as a sub-module independently, and there are line impedances between every two interfaces, and the generalized bandwidth is used for small disturbance currents.
  • the injector equates the multi-interface circuit structure to the Thevenin circuit with mirror frequency coupling; the system stability is judged by constructing the overall system relationship function matrix extending from the interface to the surroundings and the closed-loop pole position of the system;
  • Step 5.1.1 Connect n devices in parallel at the bus bar of the front end of the DC converter, corresponding to n nodes, and set each node to have a power source and its own load and exist between the connecting lines of any two devices Line impedance, where the external output characteristics of the equipment are called the source equipment, and the external output characteristics are called the load equipment.
  • Figure 5 is a schematic diagram of the circuit structure of the m interface device as an example for simplified analysis.
  • Figure 6 is an interface structure diagram of the device k.
  • the node is set to have both power supply and its own load. Among them, the pure load considers the energy provided by the power supply to be zero, and the power supply system considers its load to be zero, so that it can comply with the switching of the source device and the load device at any time during the energy interaction process. There is a line impedance between the connecting lines of any two devices.
  • Step 5.1.2 For the overall stability analysis of a single dual energy flow multi-port energy router, due to external energy storage, new energy and other DC devices, its stability will change with the number of interfaces. Model the multi-port energy router multi-parallel system by using the matrix multi-point criterion (MFC) method;
  • MFC matrix multi-point criterion
  • Step 5.1.3 Use the method of matrix multi-point criterion to determine each node in K(s) Corresponding zeros and poles; express the relational function matrix as the "ratio" of two polynomial matrices, set N(s)D -1 (s) and A -1 (s)B(s) as the given relational functions respectively Any irreducible right MFC and left MFC of matrix K(s), where N(s) represents any irreducible right MFC molecular part of a given relation function matrix K(s), and D(s) represents a given relation Any irreducible right MFC denominator part of the function matrix K
  • V k Z loadk i loadk
  • V k -V j Z linckj i linckj
  • V j is the voltage at node j
  • the output current of the front-end DC circuit on node k is:
  • i ok Y eqk (G k V k -V k )
  • Z eqk is the line impedance between node k and node j
  • G k is the proportional coefficient
  • Is load admittance Z loadk is load impedance
  • G cli represents the current proportional coefficient
  • G clv represents the voltage proportional coefficient
  • K(s) It is the closed-loop relation function matrix K(s) of the energy router system.
  • Step 6 After determining that the single dual energy flow multi-port energy router is stable through step 5, judge the stability of the entire cluster energy router system;
  • Step 6.1 When the system is obtained by hybrid connection of m energy routers, use the generalized bandwidth small disturbance current injector to obtain the output impedance matrix of the cluster energy router system, and use the following formula to denoise the cluster energy router system to obtain the cluster energy router system
  • Step 6.2 According to the relevance of the admittance matrix and the stability characteristics of the system, when the steps 1-5 determine that the self-level and mutual levels of the system are stable and the following formula does not have a right pole:
  • the cluster dual-energy flow multi-port energy router system is stable, otherwise, the cluster dual-energy flow multi-port energy router system is the energy router group level instability. Go to step 7 to reshape the three-layer impedance of the cluster energy router to make the system stable;
  • Step 7 If the cluster single-phase dual-energy flow multi-port energy router system has instability results through the above steps 2-6 identification, the self-adjusting parameter technology and passive coupling impedance are adopted for the different levels of instability links in steps 2-6 Remodeling technology and source-side cascaded impedance remodeling technology make the system stable;
  • Step 7.1 In view of the self-level instability of energy routers, according to the principle that the smaller the droop coefficient, the higher the system stability, the arctangent function is used to adjust the droop control coefficient in the back-end DC converter of a single energy router, as shown in the following formula Show, and re-execute step 1;
  • R represents the sag coefficient
  • R 0 represents the initial sag coefficient
  • k 1 and k 2 are the proportional coefficients
  • ⁇ is the translation coefficient
  • the stability of the system can be improved by reducing the sag coefficient of the system sub-modules, but as the sag coefficient decreases , The dynamic performance of the system will be partially lost. Therefore, the present invention uses the characteristics of the arctangent function to slowly adjust the coefficients. After this self-adjusting parameter technology, the system jumps to step 1.
  • Step 7.2 Aiming at the inter-level instability of energy routers, the power-side cascaded impedance control reduces the impedance of the power-side subsystem to meet the stability of the system;
  • the front-end DC converter or dual active bridge bidirectional DC-DC converter is equivalent It is a generalized rectifier, and its Eular-Largrange model is expressed as:
  • L n , R n , C d , Rd are the equivalent inductance and resistance of the front end of the generalized rectifier and the equivalent capacitance and resistance of the back end respectively, and u dc , i d , and i q are the DC front-end voltage and dq axial current, u d , u q are the dq axial voltage on the output side of the rectifier respectively; S d and S q respectively represent the switching duty cycle in the dq coordinate system, and ⁇ represents the angular velocity of the multi-port energy router system;
  • the ideal state variable of the multi-port energy router system is expressed as:
  • u dc represents the DC side voltage of the multi-port energy router system
  • x ref is the ideal state variable
  • U m is the maximum output voltage of the generalized rectifier
  • R p represents the damping injection factor, which is a symmetric positive definite damping matrix, namely
  • r p1 -r p3 all represent virtual injection resistance
  • step 5 is performed again;
  • Step 7.3 In view of the instability phenomenon of the energy router group, the system is stabilized by increasing the output admittance matrix on the power supply side, that is, reducing the output impedance value in the Thevenin equivalent circuit.
  • the virtual impedance designed is an impedance reshaping technology in a specific frequency domain.
  • the specific expression is shown in the following formula: Topologically symmetrical structure, its interconnected output source modules can be compared to generalized inverters, so its control block diagram is shown in Figure 10.
  • (f on -f lo , f on +f lo ) represents the instability frequency range
  • K represents the attenuation coefficient
  • Z vir represents the virtual impedance
  • f lo represents the lower frequency limit
  • f on represents the upper frequency limit
  • s represents the Laplace Multiplier
  • step 6 is performed again.

Abstract

本发明提供一种多端口能源路由器自-互-群多层次稳定辨识与回稳方法，涉及能源互联网技术领域。该方法基于阻抗判据的双能流多端口能源路由器稳定辨识方法和阻抗重塑回稳控制策略，首先辨识能源路由器中前端DC变换器、双有源桥双向DC-DC变换器、后端AC/DC变换器三个子系统的各自稳定性；其次利用MFC分式判据得到单项双能流多端口互耦合能源路由器单体稳定性，进而利用阻抗流图得到集群能源路由器的稳定性，最后针对以上出现的三种失稳现象，提出三层阻抗重塑回稳控制策略，分别采用自调节参数技术、无源耦合阻抗重塑技术和源侧级联阻抗重塑技术使系统稳定。该方法确保能源互联网系统整体的稳定性并实现系统的可扩展性、即插即用性和安全稳定运行性。

Description

多端口能源路由器自-互-群多层次稳定辨识与回稳方法 技术领域
本发明涉及能源互联网技术领域，尤其涉及一种多端口能源路由器自-互-群多层次稳定辨识与回稳方法。
背景技术
自二十一世纪以来，随着经济社会和电力电子变换技术的快速发展，在能源互联网中一种新型的未来可再生能源传输和管理系统(FREEDM)被人们所提出，与此同时，由于牵引变压器的体积庞大而笨重，一种新型的能源路由器成为了FREEDM的关键部件。能源路由器是融合电力电子技术和高频变压器技术，应用电力电子变换器与高频隔离变压器结合的方法，使得能源路由器相对于传统变压器来说，具有电压跌落补偿、断电补偿、瞬时电压调整、故障隔离、无功功率补偿、谐波隔离、新能源接入等优点，且其体积小、重量轻，利于模块化集成。在未来的可再生能源传输和管理系统中，能源路由器由于其功能的多样性、丰富性将会占有重要的应用地位。单台能源路由器包含前端DC变换器、双向桥式变换器和后端AC/DC变换器，由于三部分相互影响而产生的失稳现象已经越来越受到人们的重视。
现今，基于阻抗的稳定性辨识方法已经有许多种，主要分为模型阻抗稳定辨识和测量阻抗稳定辨识两大类。阻抗稳定性分析方法是通过将这个系统分为稳定的电源子系统和稳定的负载子系统，并通过广义奈斯曲线来评估整个系统的稳定性。目前为提高阻抗稳定性分析方法的性能，一些学者已经提出了相关的论述，为了降低Middlebrook判据的人造保守性问题，增益裕量和相角裕量判据、Energy Source Analysis Consortium判据、Opposing Argument判据和Three-Step Impedance判据被相继提出。为解决广义奈斯曲线的缺点，逆广义奈斯曲线判据、Mikhailov判据等被提出。为实现双向流动系统稳定性分析，Sum Type判据已经被提出。另外一些简化的稳定性判据，如G-范数稳定性判据、奇异值稳定性判据、无穷-1范数稳定性判据和无穷范数稳定性判据被相继提出。因此，基于阻抗的稳定性分析技术应用于能源路由器稳定辨识具备先天的优势。M.Khazraei首次提出了基于阻抗稳定性分析技术的能源路由器稳定性分析方法，然而，能源路由器子模块的控制策略是十分特殊的，在实际应用中难以实现。因此，能源路由器的稳定辨识仍然是一个开放性的问题，并且集群的能源路由器系统多层回稳控制也亟待提出。
发明内容
本发明要解决的技术问题是针对上述现有技术的不足，提供一种多端口能源路由器自-互-群多层次稳定辨识与回稳方法，以达到对能源路由器进行稳定辨识和回稳控制的目的。
为解决上述技术问题，本发明所采取的技术方案是：多端口能源路由器自-互-群多层次稳定辨识与回稳方法，包括以下步骤：
步骤1：对待检测的单项双能流多端口能源路由器系统进行系统参数初始化；所述系统参数包括能源路由器系统前端DC变换器、双有源桥双向DC-DC变换器、后端AC/DC变换器这三个子系统中的电阻值、电感值、电容值、线路阻抗、开关频率及多接口处储能、光伏设备；
步骤2：根据前端DC变换器的拓扑结构构建其Eular-Lagrange数学模型，并根据前端DC变换器的数学模型计算其传递函数，进而判断多端口能源路由器系统直流前端的稳定性，若判别结果为失稳，则判定多端口能源路由器系统为自层级失稳，并执行步骤7，否则执行步骤3；
步骤3：根据双有源桥双向DC-DC变换器的拓扑结构构建其Eular-Lagrange数学模型，并根据双有源桥双向DC-DC变换器的数学模型计算其传递函数，进而判断其稳定性；若判别结果为失稳，则判定多端口能源路由器系统为自层级失稳，执行步骤7，否则执行步骤4；
步骤4：根据后端AC/DC变换器的电路拓扑结构构建其Eular-Lagrange数学模型，并根据后端AC/DC变换器的数学模型计算其传递函数，根据其传递函数的奈斯曲线判定后端AC/DC变换器的稳定性，若判别结果为失稳，则判定多端口能源路由器系统为自层级失稳，并执行步骤7，否则执行步骤5；
步骤5：通过步骤2-4在确定单项双能流多端口能源路由器的基本三级独立子系统稳定后，在双有源桥双向DC-DC变换器前后级母线处接入多负载及光伏、风机这些新能源设备，进一步确定单项双能流多端口互耦合能源路由器的单体稳定性；
步骤5.1：在双有源桥双向DC-DC变换器前级处并联n台不同设备，包括负载、储能以及其他光伏、风机新能源设备；同时不考虑负载及光伏装置的独立稳定性；由于存在线路阻抗以及各个装置并联后其输入输出阻抗相互耦合影响，把多端口能源路由器系统中的每一个接口独立看作一个子模块，每两个接口间均存在线路阻抗，利用广义带宽小扰动电流注入器将多接口电路结构等效为镜像频率耦合的戴维南电路；通过构建从接口处向四周延伸的系统整体关系函数矩阵及系统的闭环极点位置进行系统稳定性的判断；
步骤5.1.1：在DC变换器前端的母线处并联n台设备，对应着n个节点，把每个节点设定为均存在电源以及其自身负载并且在任意两个设备的连接线间都存在线路阻抗，其中，设备的输出外特性表现为向外输出能量的称为源设备，输出外特性表现为消耗能量的称为载设备；
步骤5.1.2：采用矩阵多分判据(MFC)方法对多端口能源路由器多并联系统进行建模；
首先建立整个多端口能源路由器系统的关系函数矩阵，进而求得系统的闭环极点位置即可判断系统稳定性；针对由n个设备组成多端口能源路由器系统，建立n*n个关系函数组成的关系函数矩阵K(s)，矩阵中第a行b列元素为a和b两个设备间构建的关系函数；步骤5.1.3：采用矩阵多分判据的方法，判定K(s)中每个节点对应的零、极点；将关系函数矩阵表示成两个多项式矩阵之“比”，设定N(s)D -1(s)和A -1(s)B(s)分别为给定关系函数矩阵K(s)的任意不可简约的右MFC和左MFC，其中，N(s)表示给定关系函数矩阵K(s)的任意不可简约的右MFC分子部分，D(s)表示给定关系函数矩阵K(s)的任意不可简约的右MFC分母部分；A(s)表示给定关系函数矩阵K(s)的任意不可简约的右MFC分母部分，B(s)表示给定关系函数矩阵K(s)的任意不可简约的右MFC分子部分；
则K(s)的零极点表示为：K(s)的极点为det D(s)＝0的根或者det A(s)＝0的根；K(s)的零点为使N(s)或B(s)降秩的s值；
步骤5.1.3：对任意节点k的设备进行分析，k＝1，…，n，V k为节点k电压，i ok为前端直流电路输出电流，i linckj为节点k与节点j之间电流，j＝1，…，n且j≠n，Z loadk为本地负载阻抗，i loadk为本地负载电流，Z linekj为节点k与节点j之间线路阻抗；
则节点k的本地负载电压及电流描述方程为：
V k＝Z loadki loadk
节点k和节点j之间电压电流描述方程为：
V k-V j＝Z linckji linckj
其中，V j为节点j处的电压；
节点k上前端直流电路输出电流为：
i ok＝Y eqk(G kV k-V k)
其中，
Figure PCTCN2019098302-appb-000001
为节点k与节点j之间线路导纳，Z eqk为节点k与节点j之间线路阻抗，G k为比例系数；
节点k本地负载的电流表达式为：
i loadk＝Y loadkV k
其中，
Figure PCTCN2019098302-appb-000002
为负载导纳，Z loadk为负载阻抗；
节点k流入节点j的电流表达式为：
i linekj＝Y linekj(V k-V j)
其中，
Figure PCTCN2019098302-appb-000003
为节点k与节点j之间线路导纳；
由基尔霍夫定律，节点k流入电流等于流出电流，则
Figure PCTCN2019098302-appb-000004
联立上述公式，得到节点k处的等效阻抗，如下公式所示：
Figure PCTCN2019098302-appb-000005
其中，
Figure PCTCN2019098302-appb-000006
将关系函数矩阵K(s)的极点扩展至整个能源路由器及其外接设备系统进行分析，把所有节点处基尔霍夫公式结合组成矩阵形式：
Figure PCTCN2019098302-appb-000007
Figure PCTCN2019098302-appb-000008
联立上述两式并化简：
Figure PCTCN2019098302-appb-000009
其中，
Figure PCTCN2019098302-appb-000010
G cli表示电流比例系数，G clv表示电压比例系数；
矩阵
Figure PCTCN2019098302-appb-000011
为能源路由器系统的闭环关系函数矩阵K(s)，通过判定K(s)的稳定性即系统的稳定性，进而将K(s)转化为矩阵相乘的形式：
Figure PCTCN2019098302-appb-000012
即
Figure PCTCN2019098302-appb-000013
B(s)＝Y M1-Y M2；
步骤5.2：由秩判据的方法对关系矩阵K(s)进行互质的验证；由于
Figure PCTCN2019098302-appb-000014
和B(s)＝Y M1-Y M2均为n阶方阵，A(s)为非奇异矩阵，其行列式为关于s的多项式，且rank[A(s)B(s)]＝n，即满足不可简约的左MFC条件，故通过求解
Figure PCTCN2019098302-appb-000015
的根得到系统的闭环极点；观察闭环极点位于右平面个数，当极点个数为零，则系统稳定，若极点个数不为零，则系统无法稳定；同时根据对极点为零处进行的分析，判断不稳定设备位置，若判别结果为失稳，则判定多端口能源路由器系统为互层级失稳，并执行步骤7，反之则执行步骤6；
步骤6：通过步骤5在确定单项双能流多端口能源路由器单体稳定后，判断集群能源路由器整个系统的稳定性；
步骤6.1：当系统由m台能源路由器混连得到，利用广义带宽小扰动电流注入器得到集群能源路由器系统的输出阻抗矩阵，并利用下式对集群能源路由器系统进行去噪处理得到集群能源路由器系统的导纳矩阵流图；
Figure PCTCN2019098302-appb-000016
其中，TR i′j′和TG i′j′分别为两台能源路由器间的互阻和互导，i′＝1，…，m，j′＝1，…，m，i′≠j′，由于两台能源路由器从不同的角度分析，将会得到G i′j′和G j′i′为两台能源路由器从不同的角度分析得到的两组戴维南等效输出导纳矩阵，Z i′j′为第i台能源路由器向第j台能源路由器等效输出阻抗矩阵，
Figure PCTCN2019098302-appb-000017
为Z i′j′的转置矩阵；
步骤6.2：根据导纳矩阵关联性和系统稳定特性条件，当步骤1-5确定系统自层级和互层 级稳定并且下式不存在右极点：
Figure PCTCN2019098302-appb-000018
则集群双能流多端口能源路由器系统稳定，反之则集群双能流多端口能源路由器系统为能源路由器群层级失稳，执行步骤7，进行集群能源路由器三层阻抗重塑，使得系统达到稳定；
步骤7：如果通过上述步骤2-6辨识得到集群单项双能流多端口能源路由器系统存在失稳结果，则针对步骤2-6不同层次的失稳环节分别采用自调节参数技术、无源耦合阻抗重塑技术和源侧级联阻抗重塑技术使系统稳定；
步骤7.1：针对能源路由器自层级失稳现象，根据下垂系数越小系统稳定性越高的原则，分别利用反正切函数调节单台能源路由器的后端DC变换器中的下垂控制系数，如下式所示，并重新执行步骤1；
Figure PCTCN2019098302-appb-000019
其中，R表示下垂系数，R 0表示初始下垂系数，k 1和k 2是比例系数，Γ是平移系数；
步骤7.2：针对能源路由器互层级失稳现象，电源侧级联阻抗控制降低电源侧子系统的阻抗来满足系统的稳定性；将前端DC变换器或双有源桥双向DC-DC变换器等效为广义整流器，其Eular-Largrange模型表示为：
Figure PCTCN2019098302-appb-000020
其中，L n，R n，C d，R d分别为广义整流器的前端的等效电感、电阻和后端的等效电容、电阻，u dc，i d，i q分别为广义整流器直流前端电压和dq轴向电流，u d，u q分别为整流器输出侧的dq轴向电压；S d和S q分别表示d-q坐标系下的开关占空比，ω表示多端口能源路由器系统的角速度；
将上式简写为：
Figure PCTCN2019098302-appb-000021
其中，
Figure PCTCN2019098302-appb-000022
分别表示多端口能源路由器系统状态变量和终端控制；
多端口能源路由器系统理想的状态变量表示为：
Figure PCTCN2019098302-appb-000023
其中，u dc表示多端口能源路由器系统直流侧电压，x ref为理想状态变量，U m为广义整流器的最大输出电压；
构建状态变量误差x e＝x ref-x的能量函数为：
Figure PCTCN2019098302-appb-000024
因此，将广义整流器器的Eular-Largrange模型改写为：
Figure PCTCN2019098302-appb-000025
为了保证多端口能源路由器系统的误差最后一致收敛到0，引入阻尼注入因子，如下公式所示：
R dx e＝(R+R p)x e
其中，R p表示阻尼注入因子，其为对称正定阻尼矩阵，即
Figure PCTCN2019098302-appb-000026
其中，r p1-r p3均表示虚拟注入电阻；
通过调节R p保证李雅普诺夫直接稳定判据，得到能源路由器互层级回稳控制策略；经过此无源耦合阻抗重塑技术后，重新执行步骤5；
步骤7.3：针对能源路由器群层级失稳现象，通过增大电源侧输出导纳矩阵来实现系统的稳定，即降低戴维南等效电路中的输出阻抗值，单体能源路由器稳定的情况下，集群能源路由器由于相互耦合仅会诱发低频振荡和同步失稳，而非全频域失稳，因此设计的虚拟阻抗是特定频域内的阻抗重塑技术，其具体表达式如下公式所示：
Figure PCTCN2019098302-appb-000027
其中，(f on-f lo，f on+f lo)表示失稳频率区间，K表示衰减系数，Z vir表示虚拟阻抗，f lo表示频率下限，f on表示频率上限，s表示拉普拉斯乘子；
经过此源侧级联阻抗重塑技术后，重新执行步骤6。
采用上述技术方案所产生的有益效果在于：本发明提供的多端口能源路由器自-互-群多层次稳定辨识与回稳方法，从根本上解决了集群能源路由器的复杂稳定性评估问题，利用自层级稳定辨识技术消弭了传统阻抗技术的各个子模块稳定的假设条件，进而利用互层级稳定辨识技术解决了多级电力变换器件的耦合稳定性问题，最后利用群层级稳定辨识技术得到复杂能源路由器网络稳定的充要条件，有效地促进了能源互联网的发展。针对上述各个层级的稳定性问题，提出三层阻抗重塑回稳控制策略以确保能源互联网系统整体的稳定性并实现系统的可扩展性、即插即用性和安全稳定运行性。
附图说明
图1为本发明实施例提供的单项双能流多端口能源路由器结构示意图；
图2为本发明实施例提供的多端口能源路由器自-互-群多层次稳定辨识与回稳方法的流程图；
图3为本发明实施例提供的单项双能流多端口能源路由器拓扑及控制框图；
图4为本发明实施例提供的能源路由器中双向桥式电路移相控制效果图；
图5为本发明实施例提供的能源路由器多节点示意图；
图6为本发明实施例提供的能源路由器多节点等效电路图；
图7为本发明实施例提供的能源路由器中节点k处等效图；
图8为本发明实施例提供的集群能源路由器拓扑连接图；
图9为本发明实施例提供的无源耦合阻抗重塑控制框图；
图10为本发明实施例提供的源侧级联阻抗重塑控制框图。
具体实施方式
下面结合附图和实施例，对本发明的具体实施方式作进一步详细描述。以下实施例用于说明本发明，但不用来限制本发明的范围。
本实施例中，对如图1所示多端口能源路由器系统采用本发明的多端口能源路由器自-互-群多层次稳定辨识与回稳方法进行稳定性辨识和回稳；该多端口能源路由器系统包括电压电流采集模块，阻抗生成模块，通信模块，信息处理模块以及三层阻抗重塑模块等；三层阻抗重塑模块采用本发明的三层阻抗重塑回稳控制策略确保系统的整体稳定性。
多端口能源路由器自-互-群多层次稳定辨识与回稳方法，如图2所示，包括以下步骤：
步骤1：对待检测的单项双能流多端口能源路由器系统进行系统参数初始化；所述系统参数包括能源路由器系统前端DC变换器、双有源桥双向DC-DC变换器(Dual Active Bridge，即DAB)、后端AC/DC变换器这三个子系统中的电阻值、电感值、电容值、线路阻抗、开关频率及多接口处储能、光伏设备；
步骤2：根据前端DC变换器的拓扑结构构建其Eular-Lagrange数学模型，并根据前端DC变换器的数学模型计算其传递函数，进而判断多端口能源路由器系统直流前端的稳定性，若判别结果为失稳，则判定多端口能源路由器系统为自层级失稳，并执行步骤7，否则执行步骤3；
步骤2.1：根据如图3所示的单项双能流多端口能源路由器拓扑及控制框图中前端直流电路构建数学模型，其中C H是直流侧输出电容，L r是交流侧输入滤波电感，R r是交流侧等效电阻，u g是电网电压，i g是电网电流，U H是直流侧电压，D b是下垂系数，U n是直流侧额定电压，C v是引入的虚拟电容，i REC是直流侧电流和i H直流侧输出电流，H是电流前馈系数；则前端直流电路的数学表达是如下所示：
Figure PCTCN2019098302-appb-000028
PI控制器被使用作为电流控制内环，其可以表示为G i(s)＝k recpi+k recii/s。
因此，等式(1)可以被表示为如下：
Figure PCTCN2019098302-appb-000029
步骤2.2：根据图3所示的单项双能流多端口能源路由器拓扑及控制框图中的前端直流电 路控制策略，电流内环的传递函数可以被表示如下：
Figure PCTCN2019098302-appb-000030
忽略能量的损耗，根据前端直流电路两侧的功率相同，等式(3)可以被简化为如下所示：
Figure PCTCN2019098302-appb-000031
更进一步，等式(4)的传递函数如下所示：
Figure PCTCN2019098302-appb-000032
根据叠加原理，u H(s)和i gd(s)，u H(s)和i H(s)的关系分别如下所示：
Figure PCTCN2019098302-appb-000033
忽略电网电压的影响，将虚拟惯量控制器，直流输出电流反馈控制器和电压环PI控制器应用于能源路由器其小信号模型如下所示：
Figure PCTCN2019098302-appb-000034
其中，G v(s)＝k recpu+k reciu/s，
G c(s)＝G i(s)/(G i(s)+(L rs+R r)+H)，
G vir(s)＝-1/(D b+G v(s)U ns+H)
步骤2.3：根据得到的前端直流电路传递函数，通过DSP进行处理后得到数据通过SCI通信模块传递给上位机，进而通过计算其奈斯曲线，判断右极点个数，若数目为零，则此前端直流电路稳定，则继续执行步骤3。若个数不为零，则不稳定，跳转至步骤7；
步骤3：根据双有源桥双向DC-DC变换器的拓扑结构构建其Eular-Lagrange数学模型，并根据双有源桥双向DC-DC变换器的数学模型计算其传递函数，进而判断其稳定性；若判别结果为失稳，则判定多端口能源路由器系统为自层级失稳，执行步骤7，否则执行步骤4；
步骤3.1：根据双有源桥双向DC-DC变换器的功率传输控制策略，DAB模块和功率传输控制单移相控制策略通过图3，得到DAB结构功率变换；双有源桥式变换器作为能源路由器中电压等级变换与电气隔离的核心模块，高频变压器变比为n∶1，C H为高压侧直流母线电容 (该电容与前端直流电路级直流母线电容为同一电容)，C L为低压侧直流母线电容(该电容与后端交/直流电路级直流母线电容为同一电容)，L T为高频变压器漏感与辅助电感之和，U H为高压侧直流母线电压，U L为低压侧直流母线电压，U 12和U 34为DAB两侧H桥输出高频斩波电压，i T为高频变压器原侧电流，i L为DAB低压直流侧电流；
步骤3.2：单移相控制策略对于变压器变比约为1时，相对于其他移相控制策略具有更小的电流应力，同时这种控制方案更易于实现，图4为单移相控制中DAB各个开关管的驱动信号以及电压电流示意图。通过对于各段时刻变压器漏感电流及其两端电压分析，可以得出单移相控制下DAB功率传输特性。
对于DAB级功率传输特性的推导，得出DAB高压侧功率关系为：
Figure PCTCN2019098302-appb-000035
步骤3.3：根据上述所得到DAB功率传递关系，计算电压和电流传递函数，并判断其稳定性，即令上式中D s＝d(1-d)，则可以推导出DAB低压侧直流环节输出电流为：
Figure PCTCN2019098302-appb-000036
令
Figure PCTCN2019098302-appb-000037
则上述公式又可以表示成：
I L＝k DABD s      (10)
在DAB级低压侧直流环节，可以写出电容电流方程：
Figure PCTCN2019098302-appb-000038
根据上述对于DAB的模型方程推导，为了更好地贴合实际，在控制中考虑到一个延时环节G d(s)＝1/T ss+1，PI环节为G dabpi(s)＝k dabp+k dabi/s。
由于当负载电流变化时会影响到DAB级低压侧直流电压的调节特性，为了减小或者消除这种影响，在控制器中将负载电流引入前馈控制环节。
前馈环节的传递函数可以写成如下形式：
Figure PCTCN2019098302-appb-000039
其中，F为前馈系数。
为消除负载电流影响，有：
Figure PCTCN2019098302-appb-000040
因此负载电流前馈环节的传递函数F则为：
Figure PCTCN2019098302-appb-000041
将前馈系数取为F＝1/k DAB，由此推导出，引入前馈之前和引入前馈之后的直流母线电压U L和扰动量负载电流i Lo的传递函数，分别为：
Figure PCTCN2019098302-appb-000042
根据所得到DAB传递函数，通过DSP进行处理后得到数据通过SCI通信模块传递给上位机，进而通过计算其奈斯曲线，判断右极点个数，若数目为零，则此DAB稳定，则继续执行步骤4。若个数不为零，判断结果为不稳定，跳转至步骤7；
步骤4：根据后端AC/DC变换器的电路拓扑结构构建其Eular-Lagrange数学模型，并根据后端AC/DC变换器的数学模型计算其传递函数，根据其传递函数的奈斯曲线判定后端AC/DC变换器的稳定性，若判别结果为失稳，则判定多端口能源路由器系统为自层级失稳，并执行步骤7，否则执行步骤5；
步骤4.1：根据实际后端交/直流电路参数构建数学模型。后端交流电路部分拓扑结构如图3，在旋转坐标系下的DC/AC变换级的电感电流数学模型可以表示为：
Figure PCTCN2019098302-appb-000043
根据数学模型可以看出，dq轴的电气量存在耦合关系，为了消除在控制上的相互影响，确保dq轴进行独立控制，需要在控制器中引入耦合量反馈值，从而消除二者之间的耦合关系。对于电流内环的调节器采用PI控制，确保对DC/AC变换级电流的有效跟踪。如图3所示控制框图，上述方程式可以改写成：
Figure PCTCN2019098302-appb-000044
在dq坐标系下，系统拓扑层存在着电感电流的耦合关系，因此将耦合量引入到控制层，实现耦合变量的消除。解耦后的DC/AC变换级电流内环控制器模型可以表示为：
Figure PCTCN2019098302-appb-000045
考虑到采样环节以及驱动环节对控制器的延时影响，同时电压环解耦控制进一步简化为：
Figure PCTCN2019098302-appb-000046
dq轴电流内环的开环传递函数为：
Figure PCTCN2019098302-appb-000047
同时，小信号转换函数可以表述如下：
Figure PCTCN2019098302-appb-000048
对于电压外环，如图3所示，根据相似的分析可知，DC/AC变换器电容电压的数学模型可以表示为：
Figure PCTCN2019098302-appb-000049
PI控制同样应用于电流控制，公式如下：
Figure PCTCN2019098302-appb-000050
考虑到外部控制器采样延时以及对称性，电压外环的传递函数可以表示为：
Figure PCTCN2019098302-appb-000051
步骤4.2：根据所得到后端交/直流电路传递函数，通过主控单元进行处理后得到数据通过SCI通信模块传递给上位机，进而通过计算其奈斯曲线，判断右极点个数，若数目为零，则此后端交/直流电路稳定，则继续执行步骤5。若个数不为零，判断结果为不稳定，跳转至步骤7；
步骤5：通过步骤2-4在确定单项双能流多端口能源路由器的基本三级独立子系统稳定后，在双有源桥双向DC-DC变换器前后级母线处接入多负载及光伏、风机这些新能源设备，进一步确定单项双能流多端口互耦合能源路由器的单体稳定性；由于双有源桥双向DC-DC变换器变换器前后两级具有对称性，下面仅仅对前级稳定性进行详细的讲解；
步骤5.1：在双有源桥双向DC-DC变换器前级处并联n台不同设备，包括负载、储能以及其他光伏、风机新能源设备；同时不考虑负载及光伏装置的独立稳定性；由于存在线路阻抗以及各个装置并联后其输入输出阻抗相互耦合影响，把多端口能源路由器系统中的每一个接口独立看作一个子模块，每两个接口间均存在线路阻抗，利用广义带宽小扰动电流注入器将多接口电路结构等效为镜像频率耦合的戴维南电路；通过构建从接口处向四周延伸的系统整体关系函数矩阵及系统的闭环极点位置进行系统稳定性的判断；
步骤5.1.1：在DC变换器前端的母线处并联n台设备，对应着n个节点，把每个节点设定为均存在电源以及其自身负载并且在任意两个设备的连接线间都存在线路阻抗，其中，设备的输出外特性表现为向外输出能量的称为源设备，输出外特性表现为消耗能量的称为载设备；
本实施例以如图5为m接口设备电路结构示意图为例进行简化分析，图6为设备k的接口结构图，这样的拓扑结构可以推广到如图7所示的n设备中，把每个节点设定为同时存在电源及其自身负载。其中纯负载认为电源提供能量为零，供电系统认为其负载为零，这样可以符合在能量交互过程中源设备和载设备的随时切换。在任意两个设备的连接线间都存在线路阻抗。
步骤5.1.2：针对于单项双能流多端口能源路由器整体稳定性分析，由于外接储能、新能 源等直流装置，其稳定性随着接口数目的变化也会随之改变。采用矩阵多分判据(MFC)方法对多端口能源路由器多并联系统进行建模；
首先建立整个多端口能源路由器系统的关系函数矩阵，进而求得系统的闭环极点位置即可判断系统稳定性；针对由n个设备组成多端口能源路由器系统，建立n*n个关系函数组成的关系函数矩阵K(s)，矩阵中第a行b列元素为a和b两个设备间构建的关系函数；步骤5.1.3：采用矩阵多分判据的方法，判定K(s)中每个节点对应的零、极点；将关系函数矩阵表示成两个多项式矩阵之“比”，设定N(s)D -1(s)和A -1(s)B(s)分别为给定关系函数矩阵K(s)的任意不可简约的右MFC和左MFC，其中，N(s)表示给定关系函数矩阵K(s)的任意不可简约的右MFC分子部分，D(s)表示给定关系函数矩阵K(s)的任意不可简约的右MFC分母部分；A(s)表示给定关系函数矩阵K(s)的任意不可简约的右MFC分母部分，B(s)表示给定关系函数矩阵K(s)的任意不可简约的右MFC分子部分；
则K(s)的零极点表示为：K(s)的极点为det D(s)＝0的根或者det A(s)＝0的根；K(s)的零点为使N(s)或B(s)降秩的s值；
步骤5.1.3：对任意节点k的设备进行分析，k＝1，…，n，V k为节点k电压，i ok为前端直流电路输出电流，i linckj为节点k与节点j之间电流，j＝1，…，n且j≠n，Z loadk为本地负载阻抗，i loadk为本地负载电流，Z linekj为节点k与节点j之间线路阻抗；如果两个节点间相隔较近，阻抗可忽略，则阻抗为零，导纳为无穷大；
则节点k的本地负载电压及电流描述方程为：
V k＝Z loadki loadk
节点k和节点j之间电压电流描述方程为：
V k-V j＝Z linckji linckj
其中，V j为节点j处的电压；
节点k上前端直流电路输出电流为：
i ok＝Y eqk(G kV k-V k)
其中，
Figure PCTCN2019098302-appb-000052
为节点k与节点j之间线路导纳，Z eqk为节点k与节点j之间线路阻抗，G k为比例系数；
节点k本地负载的电流表达式为：
i loadk＝Y loadkV k
其中，
Figure PCTCN2019098302-appb-000053
为负载导纳，Z loadk为负载阻抗；
节点k流入节点j的电流表达式为：
i linekj＝Y linekj(V k-V j)
其中，
Figure PCTCN2019098302-appb-000054
为节点k与节点j之间线路导纳；
由基尔霍夫定律，节点k流入电流等于流出电流，则
Figure PCTCN2019098302-appb-000055
联立上述公式，得到节点k处的等效阻抗，如下公式所示：
Figure PCTCN2019098302-appb-000056
其中，
Figure PCTCN2019098302-appb-000057
将关系函数矩阵K(s)的极点扩展至整个能源路由器及其外接设备系统进行分析，把所有节点处基尔霍夫公式结合组成矩阵形式：
Figure PCTCN2019098302-appb-000058
Figure PCTCN2019098302-appb-000059
联立上述两式并化简：
Figure PCTCN2019098302-appb-000060
其中，
Figure PCTCN2019098302-appb-000061
G cli表示电流比例系数，G clv表示电压比例系数；
矩阵
Figure PCTCN2019098302-appb-000062
为能源路由器系统的闭环关系函数矩阵K(s)，通过判定K(s)的稳定性即系统的稳定性，进而将K(s)转化为矩阵相乘的形式：
Figure PCTCN2019098302-appb-000063
即
Figure PCTCN2019098302-appb-000064
B(s)＝Y M1-Y M2；
步骤5.2：由秩判据的方法对关系矩阵K(s)进行互质的验证；给定p*p和p*q的多项式矩阵A(s)和B(s)，A(s)为非奇异即满秩矩阵，若rank[A(s)B(s)]＝p，则A(s)和B(s)为左互质。由于
Figure PCTCN2019098302-appb-000065
和B(s)＝Y M1-Y M2均为n阶方阵，A(s)为非奇异矩阵，其行列式为关于s的多项式，且rank[A(s)B(s)]＝n，即满足不可简约的左MFC条件，故通过求解
Figure PCTCN2019098302-appb-000066
的根得到系统的闭环极点；观察闭环极点位于右平面个数，当极点个数为零，则系统稳定，若极点个数不为零，则系统无法稳定；同时根据对极点为零处进行的分析，判断不稳定设备位置，若判别结果为失稳，则判定多端口能源路由器系统为互层级失稳，并执行步骤7，反之则执行步骤6；
步骤6：通过步骤5在确定单项双能流多端口能源路由器单体稳定后，判断集群能源路由器整个系统的稳定性；
步骤6.1：当系统由m台能源路由器混连得到，利用广义带宽小扰动电流注入器得到集群能源路由器系统的输出阻抗矩阵，并利用下式对集群能源路由器系统进行去噪处理得到集群能源路由器系统的导纳矩阵流图；
Figure PCTCN2019098302-appb-000067
其中，TR i′j′和TG i′j′分别为两台能源路由器间的互阻和互导，i′＝1，…，m，j′＝1，…，m，i′≠j′，G i′j′和G j′i′为两台能源路由器从不同的角度分析得到的两组戴维南等效输出导纳矩阵，Z i′j′为 第i台能源路由器向第j台能源路由器等效输出阻抗矩阵，
Figure PCTCN2019098302-appb-000068
为Z i′j′的转置矩阵；本实施例中，通过两组戴维南等效输出导纳矩阵能够得到如图8所示的导纳矩阵流图。
步骤6.2：根据导纳矩阵关联性和系统稳定特性条件，当步骤1-5确定系统自层级和互层级稳定并且下式不存在右极点：
Figure PCTCN2019098302-appb-000069
则集群双能流多端口能源路由器系统稳定，反之则集群双能流多端口能源路由器系统为能源路由器群层级失稳，执行步骤7，进行集群能源路由器三层阻抗重塑，使得系统达到稳定；
步骤7：如果通过上述步骤2-6辨识得到集群单项双能流多端口能源路由器系统存在失稳结果，则针对步骤2-6不同层次的失稳环节分别采用自调节参数技术、无源耦合阻抗重塑技术和源侧级联阻抗重塑技术使系统稳定；
步骤7.1：针对能源路由器自层级失稳现象，根据下垂系数越小系统稳定性越高的原则，分别利用反正切函数调节单台能源路由器的后端DC变换器中的下垂控制系数，如下式所示，并重新执行步骤1；
Figure PCTCN2019098302-appb-000070
其中，R表示下垂系数，R 0表示初始下垂系数，k 1和k 2是比例系数，Γ是平移系数；通过降低系统子模块的下垂系数可以提高系统的稳定性，但是随着下垂系数的降低，系统的动态性能将会部分丧失，因此本发明利用反正切函数的特性来缓慢调节系数，经过此自调节参数技术后，系统跳转至步骤1。
步骤7.2：针对能源路由器互层级失稳现象，电源侧级联阻抗控制降低电源侧子系统的阻抗来满足系统的稳定性；将前端DC变换器或双有源桥双向DC-DC变换器等效为广义整流器，其Eular-Largrange模型表示为：
Figure PCTCN2019098302-appb-000071
其中，L n，R n，C d，R d分别为广义整流器的前端的等效电感、电阻和后端的等效电容、电阻， u dc，i d，i q分别为广义整流器直流前端电压和dq轴向电流，u d，u q分别为整流器输出侧的dq轴向电压；S d和S q分别表示d-q坐标系下的开关占空比，ω表示多端口能源路由器系统的角速度；
将上式简写为：
Figure PCTCN2019098302-appb-000072
其中，
Figure PCTCN2019098302-appb-000073
分别表示多端口能源路由器系统状态变量和终端控制；
多端口能源路由器系统理想的状态变量表示为：
Figure PCTCN2019098302-appb-000074
其中，u dc表示多端口能源路由器系统直流侧电压，x ref为理想状态变量，U m为广义整流器的最大输出电压；
构建状态变量误差x e＝x ref-x的能量函数为：
Figure PCTCN2019098302-appb-000075
因此，将广义整流器器的Eular-Largrange模型改写为：
Figure PCTCN2019098302-appb-000076
为了保证多端口能源路由器系统的误差最后一致收敛到0，引入阻尼注入因子，如下公式所示：
R dx e＝(R+R p)x e
其中，R p表示阻尼注入因子，其为对称正定阻尼矩阵，即
Figure PCTCN2019098302-appb-000077
其中，r p1-r p3均表示虚拟注入电阻；
通过调节R p保证李雅普诺夫直接稳定判据，得到如图9所示的能源路由器互层级回稳控制策略；经过此无源耦合阻抗重塑技术后，重新执行步骤5；
步骤7.3：针对能源路由器群层级失稳现象，通过增大电源侧输出导纳矩阵来实现系统的稳定，即降低戴维南等效电路中的输出阻抗值，单体能源路由器稳定的情况下，集群能源路由器由于相互耦合仅会诱发低频振荡和同步失稳，而非全频域失稳，因此设计的虚拟阻抗是特定频域内的阻抗重塑技术，其具体表达式如下公式所示：由于能源路由器具有拓扑对称结构，其互联输出源模块都可以比拟广义逆变器，因此其控制框图如图10所示。
Figure PCTCN2019098302-appb-000078
其中，(f on-f lo，f on+f lo)表示失稳频率区间，K表示衰减系数，Z vir表示虚拟阻抗，f lo表示频率下限，f on表示频率上限，s表示拉普拉斯乘子；
经过此源侧级联阻抗重塑技术后，重新执行步骤6。
最后应说明的是：以上实施例仅用以说明本发明的技术方案，而非对其限制；尽管参照前述实施例对本发明进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述实施例所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本发明权利要求所限定的范围。

Claims (6)

  1. 根据权利要求1所述的一种多端口能源路由器自-互-群多层次稳定辨识与回稳方法，其特征在于：包括以下步骤：
    步骤1：对待检测的单项双能流多端口能源路由器系统进行系统参数初始化；所述系统参数包括能源路由器系统前端DC变换器、双有源桥双向DC-DC变换器、后端AC/DC变换器这三个子系统中的电阻值、电感值、电容值、线路阻抗、开关频率及多接口处储能、光伏设备；
    步骤2：根据前端DC变换器的拓扑结构构建其Eular-Lagrange数学模型，并根据前端DC变换器的数学模型计算其传递函数，进而判断多端口能源路由器系统直流前端的稳定性，若判别结果为失稳，则判定多端口能源路由器系统为自层级失稳，并执行步骤7，否则执行步骤3；
    步骤3：根据双有源桥双向DC-DC变换器的拓扑结构构建其Eular-Lagrange数学模型，并根据双有源桥双向DC-DC变换器的数学模型计算其传递函数，进而判断其稳定性；若判别结果为失稳，则判定多端口能源路由器系统为自层级失稳，执行步骤7，否则执行步骤4；
    步骤4：根据后端AC/DC变换器的电路拓扑结构构建其Eular-Lagrange数学模型，并根据后端AC/DC变换器的数学模型计算其传递函数，根据其传递函数的奈斯曲线判定后端AC/DC变换器的稳定性，若判别结果为失稳，则判定多端口能源路由器系统为自层级失稳，并执行步骤7，否则执行步骤5；
    步骤5：通过步骤2-4在确定单项双能流多端口能源路由器的基本三级独立子系统稳定后，在双有源桥双向DC-DC变换器前后级母线处接入多负载及光伏、风机这些新能源设备，进一步确定单项双能流多端口互耦合能源路由器的单体稳定性；若判别结果为失稳，则判定多端口能源路由器系统为互层级失稳，并执行步骤7，反之则执行步骤6；
    步骤6：通过步骤5在确定单项双能流多端口能源路由器单体稳定后，判断集群能源路由器整个系统的稳定性；若判断结果为失稳，则集群双能流多端口能源路由器系统为能源路由器群层级失稳，执行步骤7，进行集群能源路由器三层阻抗重塑，使得系统达到稳定；
    步骤7：如果通过上述步骤2-6辨识得到集群单项双能流多端口能源路由器系统存在失稳结果，则针对步骤2-6不同层次的失稳环节分别采用自调节参数技术、无源耦合阻抗重塑技术和源侧级联阻抗重塑技术使系统稳定；
    步骤7.1：针对能源路由器自层级失稳现象，根据下垂系数越小系统稳定性越高的原则，分别利用反正切函数调节单台能源路由器的后端DC变换器中的下垂控制系数，并重新执行步骤1；
    步骤7.2：针对能源路由器互层级失稳现象，电源侧级联阻抗控制降低电源侧子系统的阻 抗来满足系统的稳定性；经过此无源耦合阻抗重塑技术后，重新执行步骤5；
    步骤7.3：针对能源路由器群层级失稳现象，通过增大电源侧输出导纳矩阵来实现系统的稳定，即降低戴维南等效电路中的输出阻抗值，单体能源路由器稳定的情况下，集群能源路由器由于相互耦合仅会诱发低频振荡和同步失稳，而非全频域失稳，因此设计的虚拟阻抗是特定频域内的阻抗重塑技术；经过此源侧级联阻抗重塑技术后，重新执行步骤6。
  2. 根据权利要求1所述的多端口能源路由器自-互-群多层次稳定辨识与回稳方法，其特征在于：所述步骤5.1的具体方法为：
    步骤5.1：在双有源桥双向DC-DC变换器前级处并联n台不同设备，包括负载、储能以及其他光伏、风机新能源设备；同时不考虑负载及光伏装置的独立稳定性；由于存在线路阻抗以及各个装置并联后其输入输出阻抗相互耦合影响，把多端口能源路由器系统中的每一个接口独立看作一个子模块，每两个接口间均存在线路阻抗，利用广义带宽小扰动电流注入器将多接口电路结构等效为镜像频率耦合的戴维南电路；通过构建从接口处向四周延伸的系统整体关系函数矩阵及系统的闭环极点位置进行系统稳定性的判断；
    步骤5.1.1：在DC变换器前端的母线处并联n台设备，对应着n个节点，，把每个节点设定为均存在电源以及其自身负载并且在任意两个设备的连接线间都存在线路阻抗，其中，设备的输出外特性表现为向外输出能量的称为源设备，输出外特性表现为消耗能量的称为载设备；
    步骤5.1.2：采用矩阵多分判据(MFC)方法对多端口能源路由器多并联系统进行建模；
    首先建立整个多端口能源路由器系统的关系函数矩阵，进而求得系统的闭环极点位置即可判断系统稳定性；针对由n个设备组成多端口能源路由器系统，建立n*n个关系函数组成的关系函数矩阵K(s)，矩阵中第a行b列元素为a和b两个设备间构建的关系函数；步骤5.1.3：采用矩阵多分判据的方法，判定K(s)中每个节点对应的零、极点；将关系函数矩阵表示成两个多项式矩阵之“比”，设定N(s)D -1(s)和A -1(s)B(s)分别为给定关系函数矩阵K(s)的任意不可简约的右MFC和左MFC，其中，N(s)表示给定关系函数矩阵K(s)的任意不可简约的右MFC分子部分，D(s)表示给定关系函数矩阵K(s)的任意不可简约的右MFC分母部分；A(s)表示给定关系函数矩阵K(s)的任意不可简约的右MFC分母部分，B(s)表示给定关系函数矩阵K(s)的任意不可简约的右MFC分子部分；
    则K(s)的零极点表示为：K(s)的极点为det D(s)＝0的根或者det A(s)＝0的根；K(s)的零点为使N(s)或B(s)降秩的s值；
    步骤5.1.3：对任意节点k的设备进行分析，k＝1，…，n，V k为节点k电压，i ok为前端直 流电路输出电流，i linckj为节点k与节点j之间电流，j＝1，…，n且j≠n，Z loadk为本地负载阻抗，i loadk为本地负载电流，Z linekj为节点k与节点j之间线路阻抗；
    则节点k的本地负载电压及电流描述方程为：
    V k＝Z loadki loadk
    节点k和节点j之间电压电流描述方程为：
    V k-V j＝Z linckji linckj
    其中，V j为节点j处的电压；
    节点k上前端直流电路输出电流为：
    i ok＝Y eqk(G kV k-V k)
    其中，
    Figure PCTCN2019098302-appb-100001
    为节点k与节点j之间线路导纳，Z eqk为节点k与节点j之间线路阻抗，G k为比例系数；
    节点k本地负载的电流表达式为：
    i loadk＝Y loadkV k
    其中，
    Figure PCTCN2019098302-appb-100002
    为负载导纳，Z loadk为负载阻抗；
    节点k流入节点j的电流表达式为：
    i linekj＝Y linekj(V k-V j)
    其中，
    Figure PCTCN2019098302-appb-100003
    为节点k与节点j之间线路导纳；
    由基尔霍夫定律，节点k流入电流等于流出电流，则
    Figure PCTCN2019098302-appb-100004
    联立上述公式，得到节点k处的等效阻抗，如下公式所示：
    Figure PCTCN2019098302-appb-100005
    其中，
    Figure PCTCN2019098302-appb-100006
    将关系函数矩阵K(s)的极点扩展至整个能源路由器及其外接设备系统进行分析，把所有节点处基尔霍夫公式结合组成矩阵形式：
    Figure PCTCN2019098302-appb-100007
    Figure PCTCN2019098302-appb-100008
    联立上述两式并化简：
    Figure PCTCN2019098302-appb-100009
    其中，
    Figure PCTCN2019098302-appb-100010
    G cli表示电流比例系数，G clv表示电压比例系数；
    矩阵
    Figure PCTCN2019098302-appb-100011
    为能源路由器系统的闭环关系函数矩阵K(s)，通过判定K(s)的稳定性即系统的稳定性，进而将K(s)转化为矩阵相乘的形式：
    Figure PCTCN2019098302-appb-100012
    即
    Figure PCTCN2019098302-appb-100013
    B(s)＝Y M1-Y M2；
    步骤5.2：由秩判据的方法对关系矩阵K(s)进行互质的验证；由于
    Figure PCTCN2019098302-appb-100014
    和B(s)＝Y M1-Y M2均为n阶方阵，A(s)为非奇异矩阵，其行列式为关于s的多项式，且rank[A(s)B(s)]＝n，即满足不可简约的左MFC条件，故通过求解
    Figure PCTCN2019098302-appb-100015
    的根得到系统的闭环极点；观察闭环极点位于右平面个数，当极点个数为零，则系统稳定，若极点个数不为零，则系统无法稳定；同时根据对极点为零处进行的分析，判断不稳定设备位置，若判别结果为失稳，则判定多端口能源路由器系统为互层级失稳，并执行步骤7，反之则执行步骤6。
  3. 根据权利要求2所述的多端口能源路由器自-互-群多层次稳定辨识与回稳方法，其特 征在于：所述步骤6的具体方法为：
    步骤6.1：当系统由m台能源路由器混连得到，利用广义带宽小扰动电流注入器得到集群能源路由器系统的输出阻抗矩阵，并利用下式对集群能源路由器系统进行去噪处理得到集群能源路由器系统的导纳矩阵流图；
    Figure PCTCN2019098302-appb-100016
    其中，TR i′j′和TG i′j′分别为两台能源路由器间的互阻和互导，i′＝1，…，m，j′＝1，…，m，i′≠j′，由于两台能源路由器从不同的角度分析，将会得到G i′j′和G j′i′为两台能源路由器从不同的角度分析得到的两组戴维南等效输出导纳矩阵，Z i′j′为第i台能源路由器向第j台能源路由器等效输出阻抗矩阵，
    Figure PCTCN2019098302-appb-100017
    为Z i′j′的转置矩阵；
    步骤6.2：根据导纳矩阵关联性和系统稳定特性条件，当步骤1-5确定系统自层级和互层级稳定并且下式不存在右极点：
    Figure PCTCN2019098302-appb-100018
    则集群双能流多端口能源路由器系统稳定，反之则集群双能流多端口能源路由器系统为能源路由器群层级失稳，执行步骤7，进行集群能源路由器三层阻抗重塑，使得系统达到稳定。
  4. 根据权利要求3所述的多端口能源路由器自-互-群多层次稳定辨识与回稳方法，其特征在于：步骤7.1所述利用反正切函数调节单台能源路由器的后端DC变换器中的下垂控制系数，如下式所示：
    Figure PCTCN2019098302-appb-100019
    其中，R表示下垂系数，R 0表示初始下垂系数，k 1和k 2是比例系数，Γ是平移系数。
  5. 根据权利要求4所述的多端口能源路由器自-互-群多层次稳定辨识与回稳方法，其特征在于：步骤7.2所述电源侧级联阻抗控制降低电源侧子系统的阻抗来满足系统的稳定性的具体方法为：
    将前端DC变换器或双有源桥双向DC-DC变换器等效为广义整流器，其Eular-Largrange模型表示为：
    Figure PCTCN2019098302-appb-100020
    其中，L n，R n，C d，R d分别为广义整流器的前端的等效电感、电阻和后端的等效电容、电阻，u dc，i d，i q分别为广义整流器直流前端电压和dq轴向电流，u d，u q分别为整流器输出侧的dq轴向电压；S d和S q分别表示d-q坐标系下的开关占空比，ω表示多端口能源路由器系统的角速度；
    将上式简写为：
    Figure PCTCN2019098302-appb-100021
    其中，
    Figure PCTCN2019098302-appb-100022
    分别表示多端口能源路由器系统状态变量和终端控制；
    多端口能源路由器系统理想的状态变量表示为：
    Figure PCTCN2019098302-appb-100023
    其中，u dc表示多端口能源路由器系统直流侧电压，x ref为理想状态变量，U m为广义整流器的最大输出电压；
    构建状态变量误差x e＝x ref-x的能量函数为：
    Figure PCTCN2019098302-appb-100024
    因此，将广义整流器器的Eular-Largrange模型改写为：
    Figure PCTCN2019098302-appb-100025
    为了保证多端口能源路由器系统的误差最后一致收敛到0，引入阻尼注入因子，如下公式所示：
    R dx e＝(R+R P)x e
    其中，R p表示阻尼注入因子，其为对称正定阻尼矩阵，即
    Figure PCTCN2019098302-appb-100026
    其中，r p1-r p3均表示虚拟注入电阻；
    通过调节R p保证李雅普诺夫直接稳定判据，得到能源路由器互层级回稳控制策略。
  6. 根据权利要求5所述的多端口能源路由器自-互-群多层次稳定辨识与回稳方法，其特征在于：步骤7.3所述特定频域内的阻抗重塑技术的具体表达式如下公式所示：
    Figure PCTCN2019098302-appb-100027
    其中，(f on-f lo，f on+f lo)表示失稳频率区间，K表示衰减系数，Z vir表示虚拟阻抗，f lo表示频率下限，f on表示频率上限，s表示拉普拉斯乘子。
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