Alternating current microgrid based on alternating current power frequency power type node

Abstract

The invention discloses an alternating current microgrid based on alternating current power frequency power type nodes, and relates to the technical field of energy storage. Comprising a power supply side, a load side and a phase-shifting transformer; the power supply side is connected with the load side through the phase-shifting transformer; the energy management unit is respectively connected with the power supply side and the load side; the energy management unit is used for collecting power supply parameters of a power supply side and load parameters of a load side, and controlling electric quantity flowing directions and corresponding electric quantity values of all paths of power supplies according to the power supply parameters and the load parameters and a preset rule; the AC unit is connected with a load side; the alternating current unit is used for converting alternating current output by each load into direct current; the charging control unit is respectively connected with the alternating current unit and the terminal load unit; and the charging control unit is used for receiving demand information of each terminal load and providing corresponding direct current for each terminal load according to the demand information. The working efficiency of the wind and light storage charging station can be improved.

Description

Technical Field

[0001] The present invention relates to the field of energy storage technology, and in particular to an AC microgrid based on AC industrial frequency power type nodes. Background Art

[0002] The mainstream application scenario in charging stations is to reduce the voltage to 380V through the distribution transformer, and then output the DC source required by the battery through the 380V rectifier module. Multiple rectifier modules are connected in parallel to increase the output power. The number of parallel charging modules can be adjusted according to needs, which is the so-called dynamic allocation of charging power. For this mainstream solution, we need to pay attention to the following points:

[0003] In the above solution, the distribution transformer not only realizes the basic function of 10kV / 380V transformation, but also solves the safety problem of 10kV grid side to user side. The low-voltage 380V Y-type grounding system has contact safety hazards. The 380V rectifier module uses high-frequency transformer isolation to solve this safety hazard. Multiple insulation increases the complexity of the system and increases system losses.

[0004] In the application scenarios of wind, solar, and storage charging stations, some adopt solutions based on the DC bus of charging piles, such as the photovoltaic and storage charging station solution of China's Huawei. The solar energy and energy storage are superimposed on the DC bus of the charging pile. When storing energy, it is still necessary to build an AC path or use a bidirectional rectifier module, which will lead to reduced reliability and increased costs. This DC microgrid solution does not solve the problem of direct integration with the existing AC power grid. It needs to adopt multi-level AC / DC, DC / DC and DC / AV conversion and then connect to the power grid, resulting in a decrease in system efficiency. Summary of the invention

[0005] The purpose of the present invention is to provide an AC microgrid based on AC industrial frequency power type nodes, which can improve the working efficiency of wind, solar, storage and charging stations.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] An AC microgrid based on an AC power frequency power type node, the AC microgrid comprising an AC power frequency power type node unit, an AC unit, a charging control unit, an energy management unit and a terminal load unit; the terminal load unit comprises a multi-channel terminal load;

[0008] The AC power frequency power node unit includes a power supply side, a load side and a phase-shifting transformer; the power supply side is connected to the load side through the phase-shifting transformer; the power supply side includes multiple power supplies; the load side includes multiple loads;

[0009] The energy management unit is connected to the power supply side and the load side respectively; the energy management unit is used to collect power supply parameters of the power supply side and load parameters of the load side, and control the power flow direction and corresponding power value of each power supply according to the power supply parameters and the load parameters according to preset rules;

[0010] The AC unit is connected to the load side; the AC unit is used to convert the AC power output by each load into DC power;

[0011] The charging control unit is connected to the AC unit and the terminal load unit respectively; the charging control unit is used to receive demand information of each terminal load and provide corresponding DC power to each terminal load according to the demand information.

[0012] Optionally, the AC unit is a three-phase rectifier bridge.

[0013] Optionally, the charging control unit includes a plurality of charging modules; the charging modules are respectively connected to the AC unit and the terminal load unit.

[0014] Optionally, the charging module includes a DC system and a processor;

[0015] The DC system is connected to the AC unit and the terminal load unit respectively;

[0016] The processor is connected to the DC system and the terminal load unit respectively;

[0017] The processor is used to receive demand information of each terminal load, generate a control signal according to the demand information and a preset control rule, and send the control signal to the DC system;

[0018] The DC system is used to provide corresponding DC power to each of the terminal loads according to the control signal.

[0019] Optionally, the charging module is a K-phase staggered parallel BUCK topology structure, a K-phase synchronous BUCK topology structure, a bidirectional staggered parallel BOOST / BUCK topology structure, or an output isolated DC / DC topology structure.

[0020] Optionally, the phase-shifting transformer includes a power supply side winding and a load side winding; the power supply side winding is connected to the power supply side; the load side winding is connected to the load side; the power supply side winding includes multiple power supply windings; each of the power supply windings is connected to the power supply side; the load side winding includes multiple load windings; each of the load windings is connected to the load side.

[0021] Optionally, the energy management unit includes an EMS energy management system and a sensor; the sensor is connected to the EMS energy management system; the sensor is arranged in the AC power frequency power type node unit; the sensor is used to collect power parameters of the power supply side and load parameters of the load side, and send the power parameters of the power supply side and the load parameters of the load side to the EMS energy management system;

[0022] The EMS energy management system is used to control the power flow direction and corresponding power value of each power source according to the power source parameters and the load parameters according to preset rules.

[0023] Optionally, the sensor includes a power supply side sensor and a load side sensor;

[0024] The power supply side sensor is respectively connected to the power supply side and the power supply side winding; the load side sensor is respectively connected to the load side and the load side winding.

[0025] Optionally, the load side winding is a multi-split phase-shifting winding.

[0026] Optionally, the load side winding is a Y phase-shift winding. According to the specific embodiment provided by the present invention, the present invention discloses the following technical effects:

[0027] The present invention proposes to form an AC microgrid system by a power frequency power type node, an energy management system and related units, which is always connected to the power grid; adjust the parameters of the controlled power source and the controlled load to achieve efficient utilization of the source grid load storage on the AC power frequency power type node, and conveniently realize the energy routing, mutual borrowing and coordinated power generation to the power grid of the AC microgrid of the AC power frequency power type node. Based on the AC microgrid of the power frequency power type node and the topological structure of the photovoltaic storage and charging scenario, the peak efficiency of its products is increased to 97%, the cost is reduced by 20%, and the energy consumption is reduced by 10%. The industrialization will have certain economic and social value. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 It is a photovoltaic storage and charging topology structure based on AC power frequency power node AC microgrid;

[0030] Figure 2 It is a schematic diagram of the power topology structure of a three-phase staggered parallel synchronous BUCK charging module;

[0031] Figure 3 It is a schematic diagram of the power topology structure of the three-phase staggered parallel BUCK charging module;

[0032] Figure 4 Schematic diagram of the power topology of the bidirectional interleaved parallel BOOST / BUCK charging module. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] The purpose of the present invention is to provide an AC microgrid based on AC industrial frequency power type nodes, which can improve the working efficiency of wind, solar, storage and charging stations.

[0035] The present invention proposes a microgrid system based on industrial frequency power nodes, which integrates multiple power sources such as wind, solar, energy storage and grid power at the power supply end for load consumption. Through the EMS energy management system, the aggregation, distribution, consumption and transmission of multiple electric energies and loads of the source, grid and load storage on the industrial frequency power node are realized; since the industrial frequency power node is always connected to the power grid, the microgrids of industrial frequency power nodes distributed in various places are formed into microgrid groups through the power grid, and energy aggregation, routing, mutual borrowing and coordinated power generation to the power grid can be realized in a single microgrid or group.

[0036] The industrial frequency power node proposed in the present invention satisfies the following conditions in the specific industrial frequency power node of photovoltaic storage and charging: grid access (V×I) + energy storage (V×I) + photovoltaic (V×I) = vehicle charging (V×I).

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] Example 1

[0039] like Figure 1 As shown, in this embodiment, an AC microgrid based on an AC industrial frequency power type node includes an AC industrial frequency power type node unit, an AC unit, a charging control unit, an energy management unit and a terminal load unit; the terminal load unit includes multiple terminal loads.

[0040] The AC industrial frequency power type node unit includes a power supply side, a load side and a phase-shifting transformer; the power supply side is connected to the load side through the phase-shifting transformer; the power supply side includes multiple power supplies; and the load side includes multiple loads.

[0041] The energy management unit is connected to the power supply side and the load side respectively; the energy management unit is used to collect power supply parameters of the power supply side and load parameters of the load side, and control the power flow direction and corresponding power value of each power supply according to preset rules based on the power supply parameters and the load parameters.

[0042] The AC unit is connected to the load side; the AC unit is used to convert the AC power output by each load into DC power.

[0043] Specifically, the AC unit is a three-phase rectifier bridge.

[0044] The charging control unit is connected to the AC unit and the terminal load unit respectively; the charging control unit is used to receive demand information of each terminal load and provide corresponding DC power to each terminal load according to the demand information.

[0045] In practical applications, the AC microgrid based on the AC power frequency power type node consists of the AC power frequency power type node unit 1, the power conversion unit 2, the charging control unit 3, the EMS energy management system unit 4 and the terminal load unit 5; the power supply side of the AC power frequency power type node unit 1 is provided with multiple energy channels, and the input power supply on the power supply side is a bidirectional reversible or irreversible power supply, which is a controlled power supply or an uncontrolled power supply; the load side is provided with multiple load channels, and the terminal load RX corresponding to each load channel is a bidirectional reversible or irreversible load, which is a controlled load or an uncontrolled load; the multiple energy channels on the power supply side are respectively provided with sensors AQ, and the multiple load channels on the load side are respectively provided with sensors Sensor NQ; the signals of sensors AQ and NQ are respectively sent to the industrial computer MCP of the 4th unit of the EMS energy management system. According to the signals of sensors AQ and NQ and the management principles of the EMS energy management system software, the relevant control signals AT of the industrial computer MCP are used to control the flow direction and amount of the controlled power supply, and realize the aggregation, distribution, absorption and transmission of multiple electric energies in the AC power frequency power type node; the second converter unit receives the three-phase AC power sent from the load side of the first unit of the AC power frequency power type node, and outputs multiple independent DC power supplies D1...DN through the three-phase rectifier bridge; the DC power output of the second converter unit is output to the terminal load unit 5 through the charging control unit 3.

[0046] Specifically, the charging control unit includes a plurality of charging modules; the charging modules are respectively connected to the AC unit and the terminal load unit.

[0047] Furthermore, the charging module includes a DC system and a processor. The DC system is connected to the AC unit and the terminal load unit respectively. The processor is connected to the DC system and the terminal load unit respectively. The processor is used to receive demand information of each terminal load, generate a control signal according to the demand information and a preset control rule, and send the control signal to the DC system. The DC system is used to provide corresponding DC power to each terminal load according to the control signal.

[0048] Preferably, if Figure 2 , Figure 3 and Figure 4 As shown, the charging module is a K-phase staggered parallel BUCK topology, a K-phase synchronous BUCK topology, a bidirectional staggered parallel BOOST / BUCK topology, or an output isolated DC / DC topology. K phase is an integer of 2, 3...12.

[0049] As a specific implementation, the phase-shifting transformer includes a power supply side winding and a load side winding; the power supply side winding is connected to the power supply side; the load side winding is connected to the load side; the power supply side winding includes multiple power supply windings; each of the power supply windings is connected to the power supply side; the load side winding includes multiple load windings; each of the load windings is connected to the load side.

[0050] In practical applications, in this implementation scheme, the input end of the charging control unit 3 is connected to the DC output of the conversion unit 2, and the output end is connected to the terminal load unit 5; the charging control unit 3 has N charging modules TN, and the charging module TN is composed of a DC / DCN system and an embedded processor MCU system. The demand information of the terminal load unit 5 is sent to the embedded processor MCU of the charging module TN via CAN, and the process of the DC / DCN system is controlled by the embedded processor MCU.

[0051] Specifically, the load side winding is a multi-split phase-shift winding.

[0052] The energy management unit includes an EMS energy management system and a sensor; the sensor is connected to the EMS energy management system; the sensor is arranged in the AC industrial frequency power type node unit; the sensor is used to collect the power supply parameters of the power supply side and the load parameters of the load side, and send the power supply parameters of the power supply side and the load parameters of the load side to the EMS energy management system.

[0053] The EMS energy management system is used to control the power flow direction and corresponding power value of each power source according to the power source parameters and the load parameters according to preset rules.

[0054] Furthermore, the load side winding is a Y-phase shift winding.

[0055] In practical applications, the first unit of the industrial frequency power type node is a special phase-shifting transformer, which has multiple power supply terminals on the power supply side and multiple split sub-phase-shifting windings on the load side. Sensors are respectively provided on the power supply channel on the power supply side and the load channel on the load side; the power supply side includes X power supply windings, X is an integer less than or equal to 20, and the power supply windings are respectively connected to external power supplies; the phase-shifting winding is a Y phase-shifting winding, Y is an integer less than or equal to 16, and the phase-shifting winding is further split into N identical sub-phase windings, N is an integer less than or equal to 18, and each sub-phase winding is respectively connected to a corresponding, independent rectifier circuit, and the N sub-phase windings respectively form N independent DC power supplies, and the electrical circuits of the sub-phase windings are independent and electrically insulated from each other.

[0056] The first unit of the AC power frequency power type node in the implementation scheme is an AC power frequency power type node phase-shifting transformer, which has three power supply terminals on the power supply side and six sub-phase-shifting windings on the load side. Sensors are respectively provided for the power supply channel on the power supply side and the load channel on the load side; the power supply side includes three power supply windings, which are respectively connected to external power supplies. Winding AC1 is connected to the power grid, and the power grid power is a bidirectional uncontrollable power supply; winding AC2 is connected to the output of the photovoltaic inverter, and the photovoltaic power is a unidirectional controllable power supply; winding AC3 is connected to the output of the energy storage PCS, and the power output of the energy storage PCS is a bidirectional controllable power supply; the load side is 3 phase-shifting windings, and the phase-shifting winding is further split into 6 sub-phase windings, each sub-phase winding is respectively connected to a three-phase rectifier bridge to form an independent 30-pulse rectifier circuit, and the 6 sub-phase windings respectively form 6 independent DC power supplies, and the electrical circuits of the sub-phase windings are independent of each other and electrically insulated.

[0057] The sensor includes a power supply side sensor and a load side sensor; the power supply side sensor is respectively connected to the power supply side and the power supply side winding; the load side sensor is respectively connected to the load side and the load side winding.

[0058] The software control strategy of the EMS energy management system unit 4 in this implementation scheme is:

[0059] Step 1: Determine the status and electrical parameters, working status and overall operation status of the grid power supply, photovoltaic power supply, energy storage power supply and load respectively.

[0060] Step 2: Based on the price of grid connection and local consumption of photovoltaic power, the price of grid connection and local consumption of energy storage and the current price of grid electricity, under the economic operation mode, select the terminal load consumption, energy storage charging or grid connection of grid electricity, photovoltaic power and energy storage power.

[0061] Step three, through the control and adjustment of the first unit of the AC industrial frequency power type node, according to steps one and two, select one or more electric energies to provide the terminal load unit 5 with the terminal load consumption electric energy, so that the provided electric energy is adapted to the electric energy required by the terminal load.

[0062] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0063] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. An AC microgrid based on AC power frequency power type nodes, characterized in that: The AC microgrid includes an AC power frequency power node unit, an AC unit, a charging control unit, an energy management unit and a terminal load unit; the terminal load unit includes multiple terminal loads; The AC power frequency power node unit includes a power supply side, a load side and a phase-shifting transformer; the power supply side is connected to the load side through the phase-shifting transformer; the power supply side includes multiple power supplies; the load side includes multiple loads; The energy management unit is connected to the power supply side and the load side respectively; The energy management unit is used to collect power parameters of the power supply side and load parameters of the load side, and control the power flow direction and corresponding power value of each power supply according to the power parameters and the load parameters according to preset rules; The AC unit is connected to the load side; the AC unit is used to convert the AC power output by each load into DC power; The charging control unit is connected to the AC unit and the terminal load unit respectively; the charging control unit is used to receive demand information of each terminal load and provide corresponding DC power to each terminal load according to the demand information.

2. The AC microgrid based on AC industrial frequency power type node according to claim 1 is characterized in that: The AC unit is a three-phase rectifier bridge.

3. The AC microgrid based on AC industrial frequency power type node according to claim 1 is characterized in that: The charging control unit includes a plurality of charging modules; the charging modules are respectively connected to the AC unit and the terminal load unit.

4. The AC microgrid based on AC industrial frequency power type node according to claim 3 is characterized in that: The charging module includes a DC system and a processor; The DC system is connected to the AC unit and the terminal load unit respectively; The processor is connected to the DC system and the terminal load unit respectively; The processor is used to receive demand information of each terminal load, generate a control signal according to the demand information and a preset control rule, and send the control signal to the DC system; The DC system is used to provide corresponding DC power to each of the terminal loads according to the control signal.

5. The AC microgrid based on AC industrial frequency power type node according to claim 3 is characterized in that: The charging module is a K-phase staggered parallel BUCK topology structure, a K-phase synchronous BUCK topology structure, a bidirectional staggered parallel BOOST / BUCK topology structure or an output isolated DC / DC topology structure.

6. The AC microgrid based on AC industrial frequency power type node according to claim 1 is characterized in that: The phase-shifting transformer includes a power supply side winding and a load side winding; the power supply side winding is connected to the power supply side; the load side winding is connected to the load side; the power supply side winding includes multiple power supply windings; each of the power supply windings is connected to the power supply side; the load side winding includes multiple load windings; each of the load windings is connected to the load side.

7. The AC microgrid based on AC industrial frequency power type node according to claim 6 is characterized in that: The energy management unit includes an EMS energy management system and a sensor; the sensor is connected to the EMS energy management system; the sensor is arranged in the AC power frequency power type node unit; the sensor is used to collect the power supply parameters of the power supply side and the load parameters of the load side, and send the power supply parameters of the power supply side and the load parameters of the load side to the EMS energy management system; The EMS energy management system is used to control the power flow direction and corresponding power value of each power source according to the power source parameters and the load parameters according to preset rules.

8. The AC microgrid based on AC industrial frequency power type node according to claim 7 is characterized in that: The sensors include power supply side sensors and load side sensors; The power supply side sensor is respectively connected to the power supply side and the power supply side winding; the load side sensor is respectively connected to the load side and the load side winding.

9. The AC microgrid based on AC industrial frequency power type node according to claim 6 is characterized in that: The load side winding is a multi-split phase-shift winding.

10. The AC microgrid based on AC industrial frequency power type node according to claim 6, characterized in that: The load side winding is a Y phase-shift winding.

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