Multi-port energy router modeling analysis method

Abstract

The invention provides a modeling analysis method for a multi-port energy router, and the method comprises the following steps: S1, obtaining a topological structure of the multi-port energy router which comprises a photovoltaic port, an energy storage port, a DC load port and a power grid port, and all the ports are connected through a T-type three-level converter; s2, any phase is selected as a research object, and the switching state of each bridge arm of the T-type three-level converter under the phase is determined; s3, constructing a power flow analysis model of the energy router, solving the control current and the control voltage of each phase based on the power flow analysis model, and adjusting the duty ratio of the PWM control signal of the switch of the AC side bridge arm according to the solved control current and the solved control voltage; and S4, determining primary side voltage and secondary side voltage and current according to the active power balance equation of the energy storage port and the direct current load port, and determining duty ratios of PWM control signals of switches of bridge arms of the energy storage port and the direct current load port according to the current and the voltage.

Description

Technical Field

[0001] The invention relates to a power system analysis method, and in particular to a multi-port energy router modeling and analysis method. Background Art

[0002] Energy routers have both flexible energy flow control and rich information flow interaction functions, and have great development potential. Scientific power electronics technology can effectively improve the energy conversion capability of user energy routers and their ability to absorb distributed renewable energy. It is of great significance to use the controllability of power electronic converters and the real-time characteristics of information flow interaction functions to flexibly and reliably dispatch power flows between microgrid systems in real time.

[0003] In the prior art, the control of the energy router has low precision, so that each port cannot meet its power demand.

[0004] Therefore, in order to solve the above technical problems, it is urgent to propose a new technical means. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a multi-port energy router modeling and analysis method, which can accurately determine the duty cycle of the PWM control signal of the bridge arm switch corresponding to each port based on the topological structure of the multi-port energy router and the power relationship of the corresponding ports, thereby realizing accurate control of the energy router.

[0006] The present invention provides a multi-port energy router modeling and analysis method, comprising the following steps:

[0007] S1, a topological structure of a multi-port energy router, the energy router includes a photovoltaic port, an energy storage port, a DC load port and a grid port, and each port is connected through a T-type three-level converter;

[0008] S2, select any phase as the research object, and determine the switching state of each bridge arm of the T-type three-level converter under this phase;

[0009] S3. Construct a power flow analysis model of the energy router, solve the control current and control voltage of each phase based on the power flow analysis model, and adjust the duty cycle of the PWM control signal of the switch of the AC side bridge arm according to the obtained control current and control voltage;

[0010] S4. Determine the primary side voltage, secondary side voltage and current according to the active power balance equation of the energy storage port and the DC load port, and determine the duty cycle of the PWM control signal of the switch of the bridge arm of the energy storage port and the DC load port according to the current and voltage.

[0011] Furthermore, the power exchanged between port l and the AC grid can be expressed as At this time, the node power equation of the energy router port l is:

[0012]

[0013] in: For ER t The voltage value of the lth port connected to the external AC grid, For ER t The phase angle difference between the AC node voltage value inside the lth port of and For ER t The active power and reactive power deviation;

[0014] The power balance flow equation is:

[0015]

[0016]

[0017] Further, step S4 specifically includes:

[0018] U d,h =R h I d,h +nU dc,h ;

[0019]

[0020]

[0021]

[0022]

[0023] U d,h is the primary voltage of the energy storage port and the load port, U c,h is the secondary voltage of the energy storage port and the load port; P d,h and P con,h are the active powers on the primary and secondary sides respectively.

[0024] Beneficial effects of the present invention: Through the present invention, based on the topological structure of the multi-port energy router and the power relationship of the corresponding ports, the duty cycle of the PWM control signal of the bridge arm switch corresponding to each port can be accurately determined, thereby achieving accurate control of the energy router. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0026] Figure 1 It is a schematic diagram of the process of the present invention.

[0027] Figure 2 This is a topological diagram of the energy router of the present invention.

[0028] Figure 3 It is an equivalent diagram of the DC-DC conversion circuit of the energy routing energy storage port and the DC load port of the present invention. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below:

[0030] The present invention provides a multi-port energy router modeling and analysis method, comprising the following steps:

[0031] S1. The topological structure of a multi-port energy router, which includes a photovoltaic port, an energy storage port, a DC load port ( Figure 2 In the example, the electric vehicle is used as a DC load) and the grid port, each port is connected through a T-type three-level converter;

[0032] S2, select any phase as the research object, and determine the switching state of each bridge arm of the T-type three-level converter under this phase;

[0033] S3. Construct a power flow analysis model of the energy router, solve the control current and control voltage of each phase based on the power flow analysis model, and adjust the duty cycle of the PWM control signal of the switch of the AC side bridge arm according to the obtained control current and control voltage;

[0034] S4. Determine the primary side voltage, secondary side voltage and current according to the active power balance equation of the energy storage port and the DC load port, and determine the duty cycle of the PWM control signal of the switch of the bridge arm of the energy storage port and the DC load port according to the current and voltage. Through the above method, based on the topological structure of the multi-port energy router and the power relationship of the corresponding ports, the duty cycle of the PWM control signal of the bridge arm switch corresponding to each port can be accurately determined, thereby realizing accurate control of the energy router.

[0035] In this embodiment, the power exchanged between port 1 and the AC power grid can be expressed as At this time, the node power equation of the energy router port l is:

[0036]

[0037] in: For ER t The voltage value of the lth port connected to the external AC grid, For ER tThe phase angle difference between the AC node voltage value inside the lth port of and For ER t The active power and reactive power deviation;

[0038] The power balance flow equation is:

[0039]

[0040]

[0042] In this embodiment, step S4 specifically includes:

[0043] U d,h =R h I d,h +nU dc,h ;

[0044]

[0045]

[0046]

[0047]

[0048] U d,h is the primary voltage of the energy storage port and the load port, U c,h is the secondary voltage of the energy storage port and the load port; P d,h and P con,h They are the active power of the primary side and the secondary side respectively. For the energy storage port, the current direction determines the primary side and the secondary side. When charging, the DC bus is the primary side, and when discharging, the DC bus is the secondary side.

[0049] The above-mentioned determination of the duty cycle by current and voltage is implemented by an existing algorithm, which will not be elaborated here.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A multi-port energy router modeling and analysis method, characterized by: The following steps are involved: S1, a topological structure of a multi-port energy router, the energy router includes a photovoltaic port, an energy storage port, a DC load port and a grid port, and each port is connected through a T-type three-level converter; S2, select any phase as the research object, and determine the switching state of each bridge arm of the T-type three-level converter under this phase; S3. Construct a power flow analysis model of the energy router, solve the control current and control voltage of each phase based on the power flow analysis model, and adjust the duty cycle of the PWM control signal of the switch of the AC side bridge arm according to the obtained control current and control voltage; S4. Determine the primary side voltage, secondary side voltage and current according to the active power balance equation of the energy storage port and the DC load port, and determine the duty cycle of the PWM control signal of the switch of the bridge arm of the energy storage port and the DC load port according to the current and voltage.

2. The multi-port energy router modeling and analysis method according to claim 1 is characterized by: The power exchanged between port l and the AC grid can be expressed as At this time, the node power equation of the energy router port l is: in: For ER t The voltage value of the lth port connected to the external AC grid, For ER t The phase angle difference between the AC node voltage value inside the lth port of and For ER t The active power and reactive power deviation; The power balance flow equation is:

3. The multi-port energy router modeling and analysis method according to claim 1 is characterized by: Step S4 specifically includes: U d,h =R h I d,h +nU dc,h ; U d,h is the primary voltage of the energy storage port and the load port, U c,h is the secondary voltage of the energy storage port and the load port; P d,h and P con,h are the active powers on the primary and secondary sides respectively.

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