Micro-grid power supply system and direct current networking energy management method

Abstract

The present application relates to a kind of micro-grid power supply system and direct current networking energy management method, belong to power supply technical field, the micro-grid power supply system includes: photovoltaic power supply unit, wind power supply unit, fuel cell power supply unit, fuel power supply unit and energy storage and energy management power supply unit;Photovoltaic power supply unit, wind power supply unit, fuel cell power supply unit, fuel power supply unit is respectively connected with energy storage and energy management power supply unit by the way of direct current networking;Photovoltaic power supply unit, wind power supply unit, fuel cell power supply unit, fuel power supply unit and energy storage and energy management power supply unit all include the following power supply mode: external AC power supply, external wireless power supply and external direct current networking power supply.The micro-grid power supply system provided by the present application can meet the demand of environmental change, improve the reliability and flexibility of power supply.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power supply, in particular to a micro-grid power supply system and a direct current networking energy management method. BACKGROUND

[0002] The micro-grid is a small-scale power generation and distribution system composed of distributed energy, energy conversion equipment, load, monitoring and protection equipment, etc., and can switch between grid-connected and island operation modes. It is an autonomous system capable of self-control and management, and the system capacity is generally several kilowatts to several megawatts.

[0003] However, the energy management strategy of the control system in the existing micro-grid power supply system only considers the simple energy distribution relationship, ignores the efficient use of renewable energy and the timely storage of renewable energy, and affects the economy and maximum efficiency of the micro-grid power supply system.

[0004] That is, the power supply mode of the existing multi-energy power supply system is single, and cannot meet the demand of environmental changes, and has poor flexibility. SUMMARY

[0005] Therefore, it is necessary to provide a micro-grid power supply system and a direct current networking energy management method to solve the problem of poor flexibility of the existing multi-energy power supply system.

[0006] In order to solve the above problems, the present application provides a micro-grid power supply system, comprising:

[0007] a photovoltaic power supply unit, a wind power supply unit, a fuel cell power supply unit, a fuel oil power supply unit and an energy storage and energy management power supply unit;

[0008] The photovoltaic power supply unit, the wind power supply unit, the fuel cell power supply unit, the fuel oil power supply unit and the energy storage and energy management power supply unit are connected through direct current networking.

[0009] The photovoltaic power supply unit, the wind power supply unit, the fuel cell power supply unit, the fuel oil power supply unit and the energy storage and energy management power supply unit all include the following power supply modes:

[0010] external AC power supply, external wireless power supply and external direct current networking power supply.

[0011] In one possible implementation, the photovoltaic power supply unit comprises a photovoltaic assembly, a photovoltaic inverter, a first energy storage battery pack, a first AC-DC converter and a first wireless energy transmission module.

[0012] The photovoltaic assembly, the first energy storage battery pack, the first AC-DC converter and the first wireless energy transmission module are connected with the photovoltaic inverter respectively.

[0013] In a possible implementation, the wind power supply unit comprises a wind wheel prime mover, a first generator, a second energy storage battery pack, an AC-DC-AC inverter, a second AC-DC converter and a second wireless energy transmission module.

[0014] The wind wheel prime mover is connected with the first generator.

[0015] The first generator, the second energy storage battery pack, the second wireless energy transmission module and the second AC-DC converter are connected with the AC-DC-AC inverter respectively.

[0016] In a possible implementation, the fuel cell power supply unit comprises a fuel cell module, a DC converter, a third energy storage battery pack, a DC-AC inverter, a third AC-DC converter and a third wireless energy transmission module.

[0017] The fuel cell module is connected with the DC converter.

[0018] The DC converter, the third energy storage battery pack, the third AC-DC converter and the third wireless energy transmission module are connected with the DC-AC inverter respectively.

[0019] In a possible implementation, the fuel oil power supply unit comprises a fuel oil prime mover, a second generator, an AC-AC converter, a fourth AC-DC converter and a fourth wireless energy transmission module.

[0020] The fuel oil prime mover is connected with the second generator.

[0021] The second generator, the fourth AC-DC converter and the fourth wireless energy transmission module are connected with the AC-AC converter respectively.

[0022] In a possible implementation, the energy storage and energy management power supply unit comprises a fourth energy storage battery pack, a bidirectional DC converter, a bidirectional energy storage inverter and a fifth wireless energy transmission module.

[0023] The fourth energy storage battery pack, the bidirectional DC converter, the bidirectional energy storage inverter and the fifth wireless energy transmission module are connected in sequence.

[0024] The application further provides a DC networking energy management method, comprising:

[0025] Based on the residual electric quantity of the energy storage and energy management power supply unit in the micro-grid power supply system, the charging current of the energy storage and energy management power supply unit is determined.

[0026] determine the charging and discharging power of the energy storage and energy management power supply unit based on the charging current and voltage of the energy storage and energy management power supply unit;

[0027] determine the DC networking power of the power supply unit in the micro-grid power supply system based on the charging and discharging power of the energy storage and energy management power supply unit and the output power of the micro-grid power supply system.

[0028] In a possible implementation, after determining the DC networking power of the power supply unit in the micro-grid power supply system, the method further includes:

[0029] determine the start-up number of the power supply unit in the micro-grid power supply system based on the DC networking power of the power supply unit;

[0030] determine the maximum output power of the micro-grid power supply system based on the start-up number of the power supply unit and the constraint condition.

[0031] In a possible implementation, the start-up number of the power supply unit satisfies the following condition:

[0032]

[0033] wherein, PDC represents the DC networking power of the power supply unit, Popt represents the optimal output power of the power supply unit, N represents the start-up number of the power supply unit, α represents the output power coefficient of the power supply unit.

[0034] In a possible implementation, the constraint condition has the following expression:

[0035]

[0036] wherein, PDC represents the DC networking power of the power supply unit, Pmax represents the maximum output DC power of the power supply unit, Pmin represents the minimum residual power, Prest represents the residual power of the power supply unit, Pmax represents the maximum residual power, PDC represents the DC networking power of the power supply unit, Pmax represents the maximum output power of the micro-grid power supply system.

[0037] ​​​​​The beneficial effects of the present application are: the micro-grid power supply system provided by the present application includes a photovoltaic power supply unit, a wind power supply unit, a fuel cell power supply unit, a fuel oil power supply unit and an energy storage and energy management power supply unit, the micro-grid power supply system includes various renewable energy sources, power supply can be obtained in various ways in the field, multiple power supply units are connected through a direct current networking mode, coordination and optimization between each power supply unit can be realized, effective management and control of the entire system can be realized, and each power supply unit includes multiple power supply modes: external alternating current power supply, external wireless power supply and external direct current networking power supply, which can meet the needs of environmental changes and improve the reliability and flexibility of power supply. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0039] Figure 1 An embodiment structure diagram of the micro-grid power supply system provided by the present application;

[0040] Figure 2 An embodiment structure diagram of the micro-grid power supply system provided by the present application;

[0041] Figure 3 An embodiment method flowchart of the direct current networking energy management method provided by the present application. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be described clearly and completely in the following description of the embodiments of the present application, with reference to the drawings. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0043] In the description of the embodiments of the present application, unless otherwise specified, the meaning of "multiple" is two or more. The association relationship of the associated objects is described as "and / or", which means that there can be three relationships, for example: A and / or B, which means that there are three cases: A exists alone, A and B exist together, and B exists alone.

[0044] The terms "first", "second", and the like in embodiments of the present application are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the technical features defined as "first" and "second" can be explicitly or implicitly included at least one of the features.

[0045] Figure 1 An embodiment of the micro-grid power supply system provided by the present application is shown in the structural schematic diagram. Figure 1 As shown in the figure, the micro-grid power supply system 100 includes:

[0046] A photovoltaic power supply unit 110, a wind power supply unit 120, a fuel cell power supply unit 130, a fuel oil power supply unit 140, and an energy storage and energy management power supply unit 150.

[0047] The photovoltaic power supply unit 110, the wind power supply unit 120, the fuel cell power supply unit 130, and the fuel oil power supply unit 140 are respectively connected to the energy storage and energy management power supply unit 150 through direct current networking.

[0048] The photovoltaic power supply unit 110, the wind power supply unit 120, the fuel cell power supply unit 130, the fuel oil power supply unit 140, and the energy storage and energy management power supply unit 150 all include the following power supply modes:

[0049] External alternating current power supply, external wireless power supply, and external direct current networking power supply.

[0050] Among them, the photovoltaic power supply unit can convert solar energy into electrical energy using solar photovoltaic panels.

[0051] The wind power supply unit can convert wind energy into electrical energy using a wind turbine.

[0052] The fuel cell power supply unit can convert chemical energy into electrical energy using a fuel cell, usually using hydrogen as fuel.

[0053] The fuel oil power supply unit can use fuel oil (such as diesel or gasoline) as energy to generate electricity.

[0054] The energy storage and energy management power supply unit can be used to store various energy (such as electrical energy, mechanical energy, etc.) and manage energy.

[0055] Each of the above power supply units includes multiple power supply modes: external alternating current power supply, external wireless power supply, and external direct current networking power supply.

[0056] External alternating current power supply, each power supply unit can independently output alternating current energy through an inverter or a converter, and the power supply capacity can be adjusted according to the load demand, meeting the requirements of different devices or scenes for power quality and demand.

[0057] Wireless power supply to the outside, wireless power supply to the outside through wireless transmission technology, the power supply capacity can be adjusted according to the load demand, increase the flexibility and convenience.

[0058] DC networking power supply to the outside, through the inverter to realize the DC networking power supply to the outside.

[0059] Multiple power supply units are connected through DC networking, that is, connected and communicated using DC power, which can realize the coordination and optimization between each power supply unit, so as to realize the effective management and control of the whole system. Thus, the micro-grid power supply system can fully utilize the advantages of different energy sources, improve the energy utilization efficiency, and also enhance the stability and reliability of the system.

[0060] Compared with the prior art, the micro-grid power supply system provided by the embodiment of the application includes a photovoltaic power supply unit, a wind power supply unit, a fuel cell power supply unit, a fuel oil power supply unit and an energy storage and energy management power supply unit. The micro-grid power supply system includes multiple renewable energy sources, which can obtain power in multiple ways in the field. Multiple power supply units are connected through DC networking, which can realize the coordination and optimization between each power supply unit, so as to realize the effective management and control of the whole system. In addition, each power supply unit includes multiple power supply modes: external AC power supply, external wireless power supply and external DC networking power supply, which can meet the demand of environmental change and improve the reliability and flexibility of power supply.

[0061] In some embodiments of the application, the photovoltaic power supply unit comprises:

[0062] A photovoltaic assembly, a photovoltaic inverter, a first energy storage battery pack, a first AC-DC converter and a first wireless energy transmission module.

[0063] The photovoltaic assembly, the first energy storage battery pack, the first AC-DC converter and the first wireless energy transmission module are connected with the photovoltaic inverter respectively.

[0064] Figure 2 As shown in FIG. 2, the photovoltaic power supply unit includes a photovoltaic assembly, a photovoltaic inverter, a first energy storage battery pack, a first AC-DC converter and a first wireless energy transmission module. Figure 2

[0065] The photovoltaic assembly can be composed of multiple solar panels, which is used to convert solar energy into DC power.

[0066] The photovoltaic inverter is used to convert the DC power generated by the photovoltaic assembly into AC power, so as to supply the household or industrial power system.

[0067] ​The first wireless energy transmission module is connected with the photovoltaic inverter, and can provide external equipment with electric energy in a wireless energy transmission power supply mode, so that remote power supply or wireless charging is realized.

[0068] The first energy storage battery pack is connected with the photovoltaic inverter, and is used for storing electric energy generated by the photovoltaic inverter, so as to be used when needed.

[0069] The first AC-DC converter is connected with the photovoltaic inverter, and is used for further converting AC electric energy converted by the photovoltaic inverter into DC electric energy, so as to be used for DC networking power supply with the energy storage and energy management unit or for specific DC equipment.

[0070] Through the above connection mode, a complete photovoltaic power generation system can be constructed, which has the functions of collecting solar energy, converting the solar energy into electric energy, storing the electric energy and remotely monitoring, has important significance in the field of renewable energy, and provides technical support for realizing clean energy utilization and intelligent energy management.

[0071] The micro-grid power supply system provided by the embodiment of the application has three external power supply modes, the first mode is to independently provide wireless energy transmission power supply, realized by a wireless energy transmission module, and the power supply capacity is adjustable according to the load demand; the second mode is to independently provide AC electric energy, realized by a photovoltaic inverter, and the power supply capacity is adjustable according to the load demand; and the third mode is to provide DC networking power supply, realized by an AC-DC converter, and the power supply capacity is adjusted by a networking energy management strategy of an energy storage and energy management power supply unit or a local three-stage charging strategy, namely, trickle charging (low-voltage pre-charging), constant current charging and constant voltage charging. The reliability and flexibility of power supply are further improved, and the demand of environmental change is met.

[0072] In some embodiments of the application, the wind power supply unit comprises:

[0073] a wind wheel prime mover, a first generator, a second energy storage battery pack, an AC-DC-AC converter, a second AC-DC converter and a second wireless energy transmission module;

[0074] The wind wheel prime mover is connected with the first generator.

[0075] The first generator, the second energy storage battery pack, the second wireless energy transmission module and the second AC-DC converter are connected with the AC-DC-AC converter respectively.

[0076] As shown in Figure 2 The wind power supply unit comprises a wind wheel prime mover, a first generator, a second energy storage battery pack, an AC-DC-AC converter, a second AC-DC converter and a second wireless energy transmission module.

[0077] The wind wheel prime mover can capture wind energy and convert it into mechanical energy.

[0078] The first generator converts the mechanical energy transmitted by the wind wheel prime mover into electrical energy and outputs alternating current.

[0079] The AC-DC-AC inverter can realize bidirectional conversion of electrical energy, converting alternating current into direct current (for energy storage or direct current load), or converting direct current into alternating current again (for connection to the power grid or alternating current load).

[0080] The second energy storage battery pack is connected with the AC-DC-AC inverter and can store the alternating current converted by the AC-DC-AC inverter for use when needed, such as when the wind is insufficient.

[0081] The second wireless energy transmission module is connected with the AC-DC-AC inverter and can provide power to external devices through wireless power supply, thereby realizing remote power supply or wireless charging.

[0082] The second AC-DC converter is connected with the AC-DC-AC inverter and can further convert the alternating current energy converted by the AC-DC-AC inverter into direct current energy for direct current networking power supply with the energy storage and energy management unit, or for use by specific direct current devices.

[0083] The above connection mode can construct a complete wind power generation system, including the functions of capturing wind energy, converting it into electrical energy, storing electrical energy, and remotely monitoring, which has important significance in the field of renewable energy and provides technical support for realizing clean energy utilization and intelligent energy management.

[0084] The micro-grid power supply system provided by the embodiment of the application has three external power supply modes, the first mode being independent external wireless energy transmission power supply realized by a wireless energy transmission module, the power supply amount being adjustable according to the load demand; the second mode being independent external alternating current power supply realized by an AC-DC-AC inverter, the power supply amount being adjustable according to the load demand; and the third mode being external direct current networking power supply realized by an AC-DC inverter, the power supply amount being adjusted by the networking energy management strategy of the energy storage and energy management power supply unit, or a local three-stage charging strategy, namely, trickle charging (low-voltage pre-charging), constant current charging, and constant voltage charging. The reliability and flexibility of power supply are further improved, and the demand for environmental changes is met.

[0085] In some embodiments of the application, the fuel cell power supply unit comprises:

[0086] The fuel cell module, the DC converter, the third energy storage battery pack, the DC-AC inverter, the third AC-DC converter, and the third wireless energy transmission module.

[0087] The fuel cell module is connected with the direct current converter;

[0088] The direct current converter, the third energy storage battery pack, the third alternating current-direct current converter and the third wireless energy transmission module are respectively connected with the direct current-alternating current inverter.

[0089] As shown in Figure 2 The fuel cell power supply unit includes a fuel cell module, a direct current converter, a third energy storage battery pack, a direct current-alternating current inverter, a third alternating current-direct current converter and a third wireless energy transmission module.

[0090] The fuel cell module can directly convert fuel (such as hydrogen) into electricity through chemical reaction.

[0091] The direct current converter can convert the direct current generated by the fuel cell module into stable direct current output.

[0092] The direct current-alternating current inverter can convert direct current into alternating current for use in household or industrial power supply systems.

[0093] The third energy storage battery pack is connected with the direct current-alternating current inverter and is used to store the electric energy generated by the direct current-alternating current inverter for use when needed.

[0094] The third wireless energy transmission module is connected with the direct current-alternating current inverter and can provide alternating current to external devices through wireless energy transmission, thereby realizing remote power supply or wireless charging.

[0095] The third alternating current-direct current converter is connected with the direct current-alternating current inverter and is used to further convert the alternating current generated by the direct current-alternating current inverter into direct current for direct current networking with the energy storage and energy management unit or for use in specific direct current devices.

[0096] The above connection mode enables the fuel cell power supply unit to efficiently manage and utilize the electric energy generated by the fuel cell and also supports wireless energy transmission technology, thereby providing a convenient power supply mode for external devices and having important significance in promoting the application of fuel cell technology and intelligent energy management.

[0097] The micro-grid power supply system provided by the embodiment of the present application has three external power supply modes for the fuel cell power supply unit, the first mode is to independently provide wireless energy transmission power supply, realized by a wireless energy transmission module, and the power supply capacity is adjustable according to the load demand; the second mode is to independently provide AC power, realized by a DC-AC inverter, and the power supply capacity is adjustable according to the load demand; and the third mode is to provide DC network power supply, realized by an AC-DC inverter, and the power supply capacity is adjusted by the network energy management strategy of the energy storage and energy management power supply unit, or a local three-stage charging strategy, namely, trickle charging (low-voltage pre-charging), constant current charging and constant voltage charging. The reliability and flexibility of power supply are further improved, and the demand for environmental changes is met.

[0098] In some embodiments of the present application, the fuel power supply unit comprises:

[0099] a fuel prime mover, a second generator, an AC-AC converter, a fourth AC-DC converter and a fourth wireless energy transmission module;

[0100] The fuel prime mover is connected with the second generator;

[0101] The second generator, the fourth AC-DC converter and the fourth wireless energy transmission module are respectively connected with the AC-AC converter.

[0102] As shown in Figure 2 The fuel power supply unit comprises a fuel prime mover, a second generator, an AC-AC converter, a fourth AC-DC converter and a fourth wireless energy transmission module.

[0103] The fuel prime mover uses fuel (such as diesel or gasoline) as energy and generates mechanical energy through the working principle of an internal combustion engine.

[0104] The second generator is driven by the fuel prime mover and is used to convert the mechanical energy generated by the fuel prime mover into electrical energy.

[0105] The AC-AC converter is used to convert the AC power generated by the second generator into AC power of a specific frequency or voltage, and the voltage, frequency and waveform parameters can be adjusted.

[0106] The fourth wireless energy transmission module is connected with the AC-AC converter, and the electrical energy generated by the AC-AC converter is transmitted to external equipment through wireless transmission, so as to realize remote power supply or wireless charging.

[0107] The fourth AC-DC converter is connected with the AC-AC converter, and can further convert the AC electrical energy converted by the AC-AC converter into DC electrical energy, so as to provide DC network power supply with the energy storage and energy management unit, or to be used by specific DC equipment.

[0108] The fuel power supply unit can convert the power energy generated by the fuel prime mover into electric energy efficiently through the above connection mode, and realize power supply to external equipment through the inverter and the wireless energy transmission module.

[0109] The fuel power supply unit has three power supply modes, the first mode is to independently provide wireless energy transmission power supply, realized by the wireless energy transmission module, and the power supply capacity is adjustable according to the load demand; the second mode is to independently provide AC power, realized by the AC-AC converter, and the power supply capacity is adjustable according to the load demand; the third mode is to provide DC network power supply, realized by the AC-DC inverter, and the power supply capacity is adjusted by the network energy management strategy of the energy storage and energy management power supply unit or the local three-stage charging strategy, namely trickle charging (low-voltage pre-charging), constant current charging and constant voltage charging. The reliability and flexibility of power supply are further improved, and the demand of environmental change is met.

[0110] In some embodiments of the present application, the energy storage and energy management power supply unit comprises:

[0111] a fourth energy storage battery pack, a bidirectional DC converter, a bidirectional energy storage inverter and a fifth wireless energy transmission module;

[0112] The fourth energy storage battery pack, the bidirectional DC converter, the bidirectional energy storage inverter and the fifth wireless energy transmission module are connected in sequence.

[0113] As shown in Figure 2 The energy storage and energy management unit comprises a fourth energy storage battery pack, a bidirectional DC converter, a bidirectional energy storage inverter and a fifth wireless energy transmission module.

[0114] The fourth energy storage battery pack is connected through the DC network mode and the first AC-DC converter, the second AC-DC converter, the third AC-DC converter and the fourth AC-DC converter, and can store the DC electric energy provided by each power supply unit.

[0115] The bidirectional DC converter and the fourth energy storage battery pack are connected, and can realize bidirectional conversion of electric energy in the DC circuit, and can convert electric energy from a DC source (such as a battery) into DC of another voltage, or operate in reverse.

[0116] The bidirectional energy storage inverter and the bidirectional DC converter are connected, and the bidirectional energy storage inverter can realize an inverter for bidirectional conversion of electric energy in an AC circuit, and can convert DC into AC (for connection to an AC load or power grid), and can also convert AC into DC (for charging a battery or supplying a DC load).

[0117] The fifth wireless energy transmission module and the bidirectional energy storage inverter are connected, and can provide power to external equipment in a wireless energy transmission power supply mode, so as to realize remote power supply or wireless charging.

[0118] Through the above connection mode, the electric energy can be effectively managed and utilized, and the energy flow and energy storage function in the system are supported.

[0119] The micro-grid power supply system provided by the embodiment of the application has three external power supply modes, the first mode is to independently provide wireless energy transmission power supply, realized by a wireless energy transmission module, and the power supply capacity is adjustable according to the load demand; the second mode is to independently provide alternating current power, realized by a bidirectional energy storage inverter alternating current load port, and the power supply capacity is adjustable according to the load demand; the third mode is to provide alternating current network power supply, realized by a bidirectional energy storage inverter and an external power grid alternating current network port. The system has a direct current network input mode, the direct current input directly charges the energy storage battery pack, and the input capacity is adjusted by a network energy management strategy of the energy storage and energy management power supply unit, or a local three-stage charging strategy of each power supply unit, namely, trickle charging (low-voltage pre-charging), constant current charging and constant voltage charging.

[0120] Figure 3 An embodiment of the direct current network energy management method provided by the application is shown in a method flowchart as shown in Figure 3 The direct current network energy management method comprises the following steps.

[0121] S301, determining the charging current of the energy storage and energy management power supply unit based on the residual capacity of the energy storage and energy management power supply unit in the micro-grid power supply system;

[0122] S302, determining the charge-discharge power of the energy storage and energy management power supply unit based on the charging current and voltage of the energy storage and energy management power supply unit;

[0123] S303, determining the direct current network power of the power supply unit in the micro-grid power supply system based on the charge-discharge power of the energy storage and energy management power supply unit and the output power of the micro-grid power supply system.

[0124] It should be noted that each power supply unit in the micro-grid power supply system has an internal direct current network function, which can be used to supply power to the energy storage and energy management power supply unit.

[0125] The direct current networking energy management method provided by the embodiment of the present application can ensure that the energy storage and energy management power unit can be charged to the required level by determining the required charging current according to the residual power of the energy storage and energy management power unit in the micro-grid power supply system, and determining the charging and discharging power according to the charging current and voltage, the charging and discharging power can reflect the current energy flow, including the charging and discharging process, so as to determine the direct current networking power of the power unit in the micro-grid power supply system according to the charging and discharging power and the output power of the micro-grid power supply system, the direct current networking power is the direct current power provided by all power units to support the operation and power supply demand of the entire micro-grid. The energy distribution and utilization in the micro-grid power supply system are effectively managed by monitoring the state and energy flow of the energy storage and energy management power unit, and the stable operation and optimal performance of the system are ensured.

[0126] Optionally, when the energy storage and energy management unit has no load output, the direct current networking input electric energy mainly meets the input charging electric energy of the energy storage battery pack. When the energy storage and energy management unit has load output, if the direct current networking input electric energy is greater than the load electric energy, the direct current networking simultaneously supplies power to the external load and charges the energy storage battery pack; if the direct current networking input electric energy is less than the load electric energy, the direct current networking input electric energy and the energy storage battery pack simultaneously supply power to the external load.

[0127] Since the light energy and the wind energy are real-time renewable energy, the electric energy of the photovoltaic power unit and the wind power unit can be preferentially utilized, then the electric energy of the fuel cell power unit and the electric energy of the fuel oil power unit, and finally the electric energy of the energy storage and energy management power unit.

[0128] Exemplarily, the residual power, the output direct current power, the optimal output direct current power and the maximum output direct current power corresponding to each power unit are respectively represented as follows:

[0129] The residual power of the energy storage battery pack of the photovoltaic power unit , the output direct current power of the photovoltaic power unit , the optimal output direct current power and the maximum output direct current power ;

[0130] The residual power of the energy storage battery pack of the wind power unit , the output direct current power of the photovoltaic power unit , the optimal output direct current power and the maximum output direct current power ;

[0131] The residual power of the energy storage battery pack of the fuel cell power unit , the output direct current power of the fuel cell power unit , the optimal output direct current power and the maximum output direct current power ;

[0132] Residual oil amount of fuel power supply unit , fuel power supply unit output direct current power , optimal output direct current power , maximum output direct current power ;

[0133] Residual energy amount of energy storage and energy management power supply unit's energy storage battery pack , energy storage and energy management power supply unit output alternating current power , optimal output alternating current power , and maximum output alternating current power ;

[0134] Direct current networking output power of micro-grid power supply system, i.e. system load power , maximum power of each power supply unit in direct current networking , charging power of energy storage and energy management power supply unit's energy storage battery pack , power of each unit in direct current networking when running with load .

[0135] Since photovoltaic power supply unit, wind power supply unit, fuel cell power supply unit, and energy storage and energy management power supply unit all have energy storage battery packs, the output power is limited by the residual energy amount of the energy storage battery pack, when the residual energy amount is less than , the output of electric energy to the outside is stopped; when the residual energy amount is greater than , the charging of the battery pack is stopped; similarly, the residual oil amount of the fuel power supply unit is , when the residual oil amount is less than , the output of electric energy to the outside is stopped.

[0136] The energy management strategy aims to make the energy storage battery pack of the energy storage and energy management power supply unit as full as possible at any time. Due to the characteristics of the energy storage battery pack, the charging power is related to the voltage and the charging current, and the charging current is related to the state of charge of the energy storage battery pack at the time, specific formulas are as follows:

[0137] (1)

[0138] wherein, represents the charging and discharging power of the energy storage battery pack of the energy storage and energy management power supply unit, represents the current voltage of the energy storage battery pack of the energy storage and energy management power supply unit, represents the charging current of the energy storage battery pack of the energy storage and energy management power supply unit.

[0139] Charging current of energy storage and energy management power supply unit​ The expression is as follows by determining the residual power of the energy storage and energy management power unit:

[0140] (2)

[0141] wherein, represents the rated charging current of the energy storage battery pack in the energy storage and energy management power unit, , , is the charging rate of the energy storage battery pack and is a positive number, , , represents a range value, .

[0142] When the micro-grid power supply system is powered by a direct current network, the power balance should follow the following relationship

[0143] (3)

[0144] wherein, is the output power of the micro-grid power supply system network, that is, the system load power; is the centralized direct current network power of each power unit; is the charging and discharging power of the energy storage battery pack of the energy storage and energy management power unit, is the efficiency of the bidirectional direct current converter and the bidirectional energy storage inverter in the energy storage and energy management power unit, is the charging and discharging direction of the energy storage battery pack in the energy storage and energy management power unit, when , when , .

[0145] The expression of the centralized direct current network power of each power unit can be obtained from formula (1) to formula (3) as follows:

[0146] (4)

[0147] The energy management strategy includes considering the state of each power unit, the power constraint, the maximum power output of each power unit in the direct current network, and the corresponding relationship between the direct current network power demand and the number of power unit starts.

[0148] In some embodiments of the present application, after determining the direct current network power of the power unit in the micro-grid power supply system, the method further comprises:

[0149] determining the number of power unit starts in the micro-grid power supply system based on the direct current network power of the power unit;

[0150] Based on the number of power supply units that are started and the constraints, the maximum output power of the microgrid power supply system is determined.

[0151] When a microgrid power supply system is connected to the grid, the maximum output power of the DC grid should follow the following relationship:

[0152] (5)

[0153] in, This indicates the maximum output power of the microgrid power supply system. Indicates power supply unit Maximum output power , It is an integer. Indicates power supply unit The output power coefficient when the remaining capacity of the energy storage battery pack is... hour ,when hour .

[0154] according to Determine the number of startup power supply units:

[0155] (6)

[0156] in, Indicates power supply unit The optimal output power, The number of power supply units that can be started, ranging from 1 to 4. Indicates power supply unit The output power coefficient when the remaining capacity of the energy storage battery pack is... hour ,when hour .

[0157] The expression for the constraint is as follows:

[0158] (7)

[0159] in, Indicates power supply unit 'output DC power' Indicates power supply unit Maximum output DC power This represents the minimum remaining battery power. Indicates power supply unit The remaining battery power, This indicates the maximum remaining battery capacity. This indicates the output power of the microgrid power supply system. representing the maximum output power of the micro-grid power supply system.

[0160] The DC networking energy management method provided by the embodiment of the present application considers the state of each power unit, the power constraint, the corresponding relationship between the DC networking power demand and the number of started power units, and calculates the output power of each power unit to ensure the reliable and safe operation of the micro-grid power supply system.

[0161] Compared with the prior art, the present application has the following advantages:

[0162] (1) The micro-grid power supply system includes various renewable energy sources, and power can be obtained in various ways in the field, and there are distributed independent power supply and networking centralized high-power supply.

[0163] (2) The internal networking mode of the micro-grid power supply system adopts a DC networking scheme, and the DC networking is simpler, safer and more reliable.

[0164] (3) The DC networking energy management strategy includes a total control management strategy and a local three-stage charging strategy. The total control management strategy considers the state of each power unit, the power constraint, the corresponding relationship between the DC networking power demand and the number of started power units, and calculates the output power of each power unit to ensure the reliable and safe operation of the micro-grid power supply system.

[0165] Correspondingly, the present application also provides a computer readable storage medium for storing computer readable programs or instructions, which can realize the steps or functions of the DC networking energy management method provided by the above method embodiments when the programs or instructions are executed by a processor.

[0166] Those skilled in the art can understand that all or part of the processes of the above-mentioned embodiments can be completed by a computer program to instruct related hardware (such as a processor, a controller, etc.) to complete, and the computer program can be stored in a computer readable storage medium. The computer readable storage medium is a disk, an optical disk, a read-only memory or a random access memory, etc.

[0167] The micro-grid power supply system and the DC networking energy management method provided by the present application are described in detail above, and specific examples are applied to explain the principles and implementation modes of the present application. The above embodiment is only used to help understand the method and its core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed, and the above description should not be understood as a limitation of the present application.

Claims

1. A direct current networked energy management method, characterized by, The method comprises the following steps: determining the charging current of the energy storage and energy management power supply unit based on the remaining power of the energy storage and energy management power supply unit in the micro-grid power supply system; determining the charging and discharging power of the energy storage and energy management power supply unit based on the charging current and voltage of the energy storage and energy management power supply unit; determining the DC networking power of the power supply unit in the micro-grid power supply system based on the charging and discharging power of the energy storage and energy management power supply unit and the output power of the micro-grid power supply system; after determining the DC networking power of the power supply unit in the micro-grid power supply system, the method further comprises the following steps: determining the start-up number of the power supply unit in the micro-grid power supply system based on the DC networking power of the power supply unit; determining the maximum output power of the micro-grid power supply system based on the start-up number of the power supply unit and the constraint condition; the start-up number of the power supply unit satisfies the following condition: wherein, represents a direct network power of the power supply unit, represents an optimal output power of the power supply unit , represents a start-up number of the power supply unit, represents an output power coefficient of the power supply unit . the micro-grid power supply system comprises a photovoltaic power supply unit, a wind power supply unit, a fuel cell power supply unit, a fuel oil power supply unit and an energy storage and energy management power supply unit; the photovoltaic power supply unit, the wind power supply unit and the fuel oil power supply unit each comprise an energy storage battery pack.

2. The DC networking energy management method according to claim 1, wherein the photovoltaic power supply unit, the wind power supply unit, the fuel cell power supply unit, the fuel oil power supply unit and the energy storage and energy management power supply unit are connected through DC networking; the photovoltaic power supply unit, the wind power supply unit, the fuel cell power supply unit, the fuel oil power supply unit and the energy storage and energy management power supply unit each comprise the following power supply modes: external AC power supply, external wireless power supply and external DC networking power supply.

3. The DC grid energy management method according to claim 1, characterized in that, The photovoltaic power supply unit comprises: a photovoltaic assembly, a photovoltaic inverter, a first energy storage battery pack, a first AC-DC converter and a first wireless energy transmission module; the photovoltaic assembly, the first energy storage battery pack, the first AC-DC converter and the first wireless energy transmission module are connected to the photovoltaic inverter.

4. The DC grid energy management method according to claim 1, characterized in that, The wind power supply unit comprises: a wind turbine prime mover, a first generator, a second energy storage battery pack, an AC-DC-AC inverter, a second AC-DC converter and a second wireless energy transmission module; the wind turbine prime mover is connected to the first generator; the first generator, the second energy storage battery pack, the second wireless energy transmission module and the second AC-DC converter are connected to the AC-DC-AC inverter.

5. The DC grid energy management method according to claim 1, characterized in that, The fuel cell power supply unit comprises: a fuel cell module, a DC converter, a third energy storage battery pack, a DC-AC inverter, a third AC-DC converter and a third wireless energy transmission module; the fuel cell module is connected to the DC converter; the DC converter, the third energy storage battery pack, the third AC-DC converter and the third wireless energy transmission module are connected to the DC-AC inverter.

6. The DC grid energy management method according to claim 1, characterized in that, The fuel oil power supply unit comprises: a fuel oil prime mover, a second generator, an AC-AC converter, a fourth AC-DC converter and a fourth wireless energy transmission module; The fuel prime mover is connected with the second generator; The second generator, the fourth AC-DC converter and the fourth wireless energy transmission module are connected with the AC-AC converter.

7. The DC grid energy management method according to claim 1, characterized in that, The energy storage and energy management power supply unit comprises: A fourth energy storage battery pack, a bidirectional DC converter, a bidirectional energy storage inverter and a fifth wireless energy transmission module; The fourth energy storage battery pack, the bidirectional DC converter, the bidirectional energy storage inverter and the fifth wireless energy transmission module are connected in sequence.

8. The DC grid energy management method according to claim 1, characterized by, The expression of the constraint condition is as follows: wherein, represents the output DC power of the power supply unit , represents the maximum output DC power of the power supply unit , represents the minimum value of the remaining power, represents the remaining power of the power supply unit , represents the maximum value of the remaining power, represents the DC networking power of the power supply unit, represents the maximum output power of the micro-grid power supply system.

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