Communication control circuit and method for centralized distributed optical storage power generation system

Abstract

The invention belongs to the technical field of photovoltaic power generation, and particularly relates to a centralized distributed optical storage power generation system communication control circuit and method. The circuit comprises a photovoltaic module, an energy storage battery and a superior scheduling module, wherein the photovoltaic module is sequentially connected with a photovoltaic DC / DC and a photovoltaic inverter; the circuit further comprises a GOOSE network switch, and the GOOSE network switch is downwards connected with the energy storage battery, the photovoltaic DC / DC and the photovoltaic inverter. According to the invention, the coordination controller, the GOOSE network switch and the MMS network switch are added in the traditional centralized and distributed inverter AC coupling mode optical storage power generation system, a communication control system is reconstructed, the coordination controller directly controls the photovoltaic DC / DC, the photovoltaic inverter and the PCS, the response is fast, the precision is high, and the coordination controller can output power in real time according to the inversion module, so that the power generation efficiency is improved. And the output threshold of the optical storage system is flexibly adjusted.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic power generation, and in particular relates to a communication control circuit and method for a centralized and distributed photovoltaic power generation system. Background Art

[0002] At present, the control method of the photovoltaic power generation system configured with centralized and distributed inverter AC coupling mode is relatively simple, and the communication control is collected and controlled by the battery management system (Battery Management System, BMS), energy management system (Energy Management Unit, EMU), and data acquisition device (Energy Management System, EMS).

[0003] ① When transmitting upward: First, the BMS collects all battery information and transmits it to the EMU. The EMU collects BMS information, power conversion system (PCS) information, energy storage meter information and other information and uploads them to the EMS. The EMS collects EMU information, photovoltaic inverter information, box transformer low-voltage side information and other information for upward transmission;

[0004] ② When controlling downward: First, the dispatcher sends the information to the EMS. The EMS sends instructions to the EMU by comparing the power size. The EMU controls the charging and discharging of the energy storage battery. The EMS also controls the inverter module to control the photovoltaic output.

[0005] Long response time: When EMS directly collects information from each photovoltaic power generation unit in the site, the huge amount of data will place higher requirements on the EMS hardware performance and software control capabilities. Since a control system needs to control dozens or even hundreds of photovoltaic inverters and PCSs to run simultaneously, from data collection (including protocol conversion), logical judgment, command issuance to on-site response, the overall closed-loop operation time will be as long as tens of seconds, which cannot give full play to the advantages of rapid energy storage regulation.

[0006] Poor control accuracy: Since the information of photovoltaic and energy storage is collected separately, and then the inverter output and energy storage charging and discharging are controlled separately, the time for uploading and adjusting the response of the two parts of photovoltaic and energy storage is different. From the perspective of the overall output of the photovoltaic and energy storage power generation unit, the coordination consistency of photovoltaic power generation and energy storage charging and discharging is poor, resulting in large fluctuations in the output of the photovoltaic and energy storage power generation unit.

[0007] Single control mode: The existing AGC / AVC system at the station control layer can only use the rated capacity of the transformer of each photovoltaic power generation unit as the maximum control power of the power generation unit's grid connection point, and the output threshold remains unchanged. It is not possible to dynamically adjust the daily maximum output threshold of the grid connection point according to the actual weather, resulting in low energy storage utilization in cloudy weather and energy storage not working in rainy weather. At the same time, the output threshold issued by the existing AGC / AVC only considers photovoltaic output and does not consider the role of energy storage, making the utilization rate of energy storage lower in actual operation. Summary of the invention

[0008] In view of the above problems, the present invention provides a communication control circuit for a centralized and distributed photovoltaic storage power generation system, the circuit comprising a photovoltaic module, an energy storage battery and an upper-level scheduling module, the photovoltaic module being sequentially connected to a photovoltaic DC / DC and a photovoltaic inverter; the circuit further comprises:

[0009] A GOOSE network switch, wherein the GOOSE network switch is respectively connected to the energy storage battery, the photovoltaic DC / DC and the photovoltaic inverter;

[0010] A coordination controller, wherein the coordination controller is connected to the GOOSE network switch at the bottom, connected to the upper-level dispatching module via an optical fiber at the top, and connected to the low-voltage side circuit of the box-type transformer via a cable;

[0011] The MMS network switch is connected to the photovoltaic inverter, the photovoltaic DC / DC and the energy storage battery respectively at the bottom, and is connected to the upper-level scheduling module via optical fiber at the top.

[0012] Preferably, the circuit further comprises an energy storage converter, wherein the energy storage converter is connected to the energy storage battery at the bottom and connected to the GOOSE network switch at the top.

[0013] Preferably, the circuit further comprises an energy management system, wherein the energy management system is connected to the photovoltaic DC / DC at the bottom and to the MMS network switch at the top.

[0014] Preferably, the circuit further comprises an energy storage watt-hour meter and a transformer signal non-electric quantity measurement module, and the energy storage watt-hour meter and the transformer signal non-electric quantity measurement module are connected to the energy management system.

[0015] Preferably, the energy storage watt-hour meter includes a DC energy storage watt-hour meter and an AC energy storage watt-hour meter.

[0016] The present invention also proposes a communication control method for a centralized and distributed photovoltaic power generation system, the control method comprising:

[0017] The GOOSE network switch stores the data of energy storage batteries, photovoltaic DC / DC and photovoltaic inverters into the GOOSE network;

[0018] The MMS network switch obtains the data of energy storage batteries and photovoltaic DC / DC, and uploads the data to the upper-level dispatch module;

[0019] The coordination controller obtains the required data from the GOOSE network, collects the current of the low-voltage side circuit of the box-type transformer, and uploads it to the upper-level dispatching module.

[0020] Preferably, the GOOSE network switch stores the data of the energy storage battery in the GOOSE network, including:

[0021] The energy storage battery data is uploaded to the energy storage converter;

[0022] The GOOSE network switch stores the data of the energy storage battery in the energy storage inverter into the GOOSE network.

[0023] Preferably, the MMS network switch acquires photovoltaic DC / DC data, including:

[0024] The data of the photovoltaic DC / DC is uploaded to the energy management system;

[0025] The MMS network switch obtains photovoltaic DC / DC data from the energy management system.

[0026] Preferably, the method further comprises:

[0027] The MMS network switch obtains data from the energy storage watt-hour meter and the transformer signal non-electricity measurement module through the energy management system, and uploads the data to the upper-level scheduling module.

[0028] Preferably, the energy storage watt-hour meter includes a DC energy storage watt-hour meter and an AC energy storage watt-hour meter.

[0029] The present invention has the following beneficial effects:

[0030] The present invention adds a coordination controller, a GOOSE network switch and an MMS network switch to the photovoltaic storage power generation system in the traditional centralized and distributed inverter AC coupling mode, and rebuilds the communication control system. The coordination controller directly controls the photovoltaic DC / DC, photovoltaic inverter, and PCS, with fast response and high precision. In addition, the coordination controller can flexibly adjust the output threshold of the photovoltaic storage system according to the real-time output of the inverter module.

[0031] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by implementing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are 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.

[0033] Figure 1 A primary diagram of a photovoltaic power generation system configured in a centralized or distributed inverter AC coupling mode in an embodiment of the present invention is shown;

[0034] Figure 2 A communication block diagram of a photovoltaic power generation system configured in a centralized or distributed inverter AC coupling mode in an embodiment of the present invention is shown;

[0035] Figure 3 A control diagram of a photovoltaic power generation system configured in a centralized or distributed inverter AC coupling mode in an embodiment of the present invention is shown;

[0036] Figure 4 A schematic diagram of a coordination controller module in an embodiment of the present invention is shown;

[0037] Figure 5 A diagram showing a communication control method for a centralized and distributed photovoltaic power generation system in an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0038] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as being limited to the examples set forth herein; on the contrary, these embodiments are provided so that the present disclosure will be more comprehensive and complete, and the concepts of the example embodiments are fully conveyed to those skilled in the art. The described features, structures, or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced while omitting one or more of the specific details, or other methods, components, devices, steps, etc. may be adopted. In other cases, known technical solutions are not shown or described in detail to avoid obscuring various aspects of the present disclosure.

[0039] In addition, the accompanying drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or implemented in one or more hardware units or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0040] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the steps. For example, some steps may be decomposed, while some steps may be combined or partially combined, so the actual execution order may change according to the actual situation.

[0041] The terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example.

[0042] In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or sub-modules is not necessarily limited to those steps or sub-modules explicitly listed, but may include other steps or sub-modules not explicitly listed or inherent to these processes, methods, products, or apparatuses.

[0043] The present invention adds a coordination controller, a GOOSE network switch and an MMS network switch to the photovoltaic storage power generation system in the traditional centralized and distributed inverter AC coupling mode, and rebuilds the communication control system. The coordination controller directly controls the photovoltaic DC / DC, photovoltaic inverter, and PCS, with fast response and high precision. In addition, the coordination controller can flexibly adjust the output threshold of the photovoltaic storage system according to the real-time output of the inverter module.

[0044] like Figure 1 As shown, the present invention includes an AC-coupled photovoltaic storage system of PCS, in which both the photovoltaic and energy storage systems are connected to the AC bus on the low-voltage side of the box-type transformer. After receiving instructions from the coordination controller, the photovoltaic inverter controls the output of the photovoltaic system, and after receiving instructions from the coordination controller, the PCS controls the charging and discharging of the energy storage system.

[0045] like Figure 2As shown, the present invention proposes a communication control circuit for a centralized and distributed photovoltaic storage power generation system, the circuit comprising a photovoltaic module, an energy storage battery and an upper-level scheduling module, the photovoltaic module is sequentially connected to a photovoltaic DC / DC and a photovoltaic inverter; the circuit also includes:

[0046] A GOOSE network switch, wherein the GOOSE network switch is respectively connected to the energy storage battery, the photovoltaic DC / DC and the photovoltaic inverter;

[0047] A coordination controller, wherein the coordination controller is connected to the GOOSE network switch at the bottom, connected to the upper-level dispatching module via an optical fiber at the top, and connected to the low-voltage side circuit of the box-type transformer via a cable;

[0048] The MMS network switch is connected to the photovoltaic inverter, the photovoltaic DC / DC and the energy storage battery respectively at the bottom, and is connected to the upper-level scheduling module via optical fiber at the top.

[0049] The circuit also includes an energy storage converter, which is connected to an energy storage battery at the bottom and to a GOOSE network switch at the top.

[0050] The circuit also includes an energy management system, which is connected to the photovoltaic DC / DC at the bottom and to the MMS network switch at the top.

[0051] The circuit also includes an energy storage watt-hour meter and a transformer signal non-electrical quantity measurement module, and the energy storage watt-hour meter and the transformer signal non-electrical quantity measurement module are connected to the energy management system; the energy storage watt-hour meter includes a DC energy storage watt-hour meter and an AC energy storage watt-hour meter.

[0052] Specifically, in Figure 2 In the GOOSE network, the GOOSE network switch is connected to the PCS, PV DC / DC, and PV inverter (inverter module DC / AC) through the network port (RJ45) downward, and the protocol is IEC 61850-GOOSE; it is connected to the coordination controller through the network port upward, and the protocol is IEC 61850-GOOSE.

[0053] The MMS network switch is connected to the photovoltaic inverter (inverter module DC / AC), BMS, and EMU through the network port (RJ45) downward, and the protocol is IEC61850-MMS; it is connected to the fiber optic terminal box through the optical port upward, and the protocol is IEC61850-MMS.

[0054] The energy management system (EMU) is connected to the photovoltaic DC / DC, energy storage meter, transformer signal non-electric measurement module, etc. through the RS485 serial port downward; and is connected to the MMS network through the network port upward.

[0055] The coordination controller is connected to the GOOSE network and the current information on the low-voltage side of the box-type transformer downward, and is connected to the optical fiber distribution frame through the optical port upward. The protocol is IEC 61850.

[0056] BMS monitors the energy storage battery information and uploads it to PCS and MMS network through the network port.

[0057] The GOOSE network collects information from PCS, PV DC / DC, and PV inverters and uploads it to the coordination controller;

[0058] The MMS network collects BMS information and EMU information and uploads it to the upper scheduling layer;

[0059] The coordinated controller uses one cable to directly collect the current information on the low-voltage side of the box-type transformer from the transformer;

[0060] BMS collects battery information, and EMU collects information such as electricity meters.

[0061] like Figure 3 As shown, the control system controls:

[0062] (1) The coordination controller is connected to the station control layer A, B, and C systems respectively, accepts control instructions from each system, and realizes steady-state (AGC / AVC control) and transient (primary frequency modulation control) operation. The communication interfaces are independent of each other and support IEC 61850. It directly collects information from the photovoltaic DC / DC, energy storage converter (PCS), and photovoltaic inverter inside the photovoltaic power generation unit and supports IEC 61850.

[0063] (2) The coordinated controller directly collects the analog values ​​of voltage and current on the low-voltage side of the boost transformer.

[0064] (3) The coordination controller is connected to the action signal (dry contact) of the step-up transformer measurement and control device (including protection function).

[0065] (4) The coordinated controller output controls the photovoltaic inverter, energy storage converter (PCS), photovoltaic DC / DC, and can also control the opening and closing of the boost transformer low voltage side circuit breaker and the energy storage device circuit breaker.

[0066] (5) The coordination controller collects the internal information of the photovoltaic and energy storage power generation units in real time. It can accept various system control instructions from the station control layer, coordinate photovoltaic power generation and energy storage charging and discharging according to the remote control instructions, and realize photovoltaic and energy storage combined power generation (steady-state operation), peak load regulation (steady-state operation), primary frequency regulation (transient operation) and other functions; it can also automatically and dynamically set the output control power threshold for the day on-site based on the collected photovoltaic output value and compare it with the rated capacity of the step-up transformer, and use this threshold as an instruction to realize photovoltaic and energy storage combined power generation (steady-state operation).

[0067] like Figure 4As shown in the figure, the coordination controller is a controller that includes an operation module, a control module, an input module, and an output module.

[0068] Operation logic:

[0069] ① The coordination controller receives the scheduling instruction P1, compares P1 with 1.1 times the rated power of the transformer substation, calculates the minimum value of the two as Pmax (here to ensure that Pmax does not exceed 1.1 times the rated power of the transformer substation), then collects the power P of the photovoltaic inverter. Then, the coordination controller compares P with Pmax. When P = Pmax, the energy storage system neither charges nor discharges. When P > Pmax, the coordination controller controls the PCS to start charging. When P < Pmax, the coordination controller controls the PCS to start discharging. After the energy storage system operates, the coordination controller collects the power P of the low-voltage side of the transformer substation as the feedback value, compares P with Pmax, and then uses the coordination controller for correction again to make P = Pmax.

[0070] Or ② The coordination controller does not accept the scheduling instruction, compares the collected power P at the photovoltaic inverter with 1.1 times the rated power of the transformer substation, takes the smaller value as Pmax, and the rest of the calculation logic remains unchanged.

[0071] The control module requires that the coordination controller can directly control the photovoltaic inverter or its data collector, photovoltaic DC / DC, PCS, etc., can control multiple PCSs to operate in parallel, perform power balancing distribution of multiple PCSs according to the SOC values of each battery pack, and balance the SOC values of each battery pack. The upper communication interfaces are independent and can accept and quickly execute various superior schedules. It can automatically set dynamic output control thresholds for the photovoltaic energy storage power generation unit locally according to the real-time collected photovoltaic output and different weather conditions to avoid the problems of low energy storage utilization rate in cloudy weather and inability to put the energy storage into operation in overcast weather.

[0072] The input and output module is required to have various interface types such as multiple network ports, optical ports, serial ports, etc., and the protocol supports unified specifications such as IEC 61850, IEC604, and Modbus.

[0073] As Figure 5 shown, the present invention also proposes a control method for the communication control circuit of the centralized and decentralized photovoltaic energy storage power generation system, and the control method includes the following steps:

[0074] S1 The GOOSE network switch stores the data of the energy storage battery, photovoltaic DC / DC, and photovoltaic inverter into the GOOSE network;

[0075] S2 The MMS network switch obtains the data of the energy storage battery and photovoltaic DC / DC, and uploads the data to the superior scheduling module;

[0076] The S3 coordination controller obtains the required data from the GOOSE network, collects the current of the low-voltage side circuit of the box-type transformer, and uploads it to the upper-level dispatching module.

[0077] Specifically, the S1 GOOSE network switch stores the energy storage battery data in the GOOSE network, including:

[0078] The energy storage battery data is uploaded to the energy storage converter;

[0079] The GOOSE network switch stores the data of the energy storage battery in the energy storage inverter into the GOOSE network.

[0080] Specifically, the S2 MMS network switch obtains the data of the photovoltaic DC / DC, including:

[0081] The data of the photovoltaic DC / DC is uploaded to the energy management system;

[0082] The MMS network switch obtains photovoltaic DC / DC data from the energy management system.

[0083] The method further comprises:

[0084] S4 The MMS network switch obtains data from the energy storage watt-hour meter and the transformer signal non-electricity measurement module through the energy management system, and uploads it to the upper-level scheduling module.

[0085] Those skilled in the art should understand that although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible to modify the technical solutions described in the aforementioned embodiments, or to make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A communication control circuit for a centralized and distributed photovoltaic power generation system. It is characterized in that The circuit includes a photovoltaic module, an energy storage battery and an upper-level scheduling module, wherein the photovoltaic module is sequentially connected to a photovoltaic DC / DC and a photovoltaic inverter; the circuit also includes: A GOOSE network switch, wherein the GOOSE network switch is respectively connected to the energy storage battery, the photovoltaic DC / DC and the photovoltaic inverter; A coordination controller, wherein the coordination controller is connected to the GOOSE network switch at the bottom, connected to the upper-level dispatching module via an optical fiber at the top, and connected to the low-voltage side circuit of the box-type transformer via a cable; The MMS network switch is connected to the photovoltaic inverter, the photovoltaic DC / DC and the energy storage battery respectively at the bottom, and is connected to the upper-level scheduling module via optical fiber at the top.

2. According to the communication control circuit of the centralized and distributed photovoltaic power generation system of claim 1, It is characterized in that The circuit also includes an energy storage converter, which is connected to an energy storage battery at the bottom and to a GOOSE network switch at the top.

3. According to the communication control circuit of the centralized and distributed photovoltaic power generation system of claim 1, It is characterized in that The circuit also includes an energy management system, which is connected to the photovoltaic DC / DC at the bottom and to the MMS network switch at the top.

4. The communication control circuit of the centralized and distributed photovoltaic power generation system according to claim 3, It is characterized in that The circuit also includes an energy storage watt-hour meter and a transformer signal non-electric quantity measurement module, and the energy storage watt-hour meter and the transformer signal non-electric quantity measurement module are connected to the energy management system.

5. According to claim 4, the communication control circuit of the centralized and distributed photovoltaic power generation system, It is characterized in that The energy storage watt-hour meter includes a DC energy storage watt-hour meter and an AC energy storage watt-hour meter.

6. A control method for a communication control circuit of a centralized and distributed photovoltaic power generation system according to any one of claims 1 to 5, It is characterized in that The control method comprises: The GOOSE network switch stores the data of energy storage batteries, photovoltaic DC / DC and photovoltaic inverters into the GOOSE network; The MMS network switch obtains the data of energy storage batteries and photovoltaic DC / DC, and uploads the data to the upper-level dispatch module; The coordination controller obtains the required data from the GOOSE network, collects the current of the low-voltage side circuit of the box-type transformer, and uploads it to the upper-level dispatching module.

7. The control method according to claim 6, It is characterized in that The GOOSE network switch stores the data of the energy storage battery in the GOOSE network, including: The energy storage battery data is uploaded to the energy storage converter; The GOOSE network switch stores the data of the energy storage battery in the energy storage inverter into the GOOSE network.

8. The control method according to claim 6, It is characterized in that The MMS network switch obtains photovoltaic DC / DC data, including: The data of the photovoltaic DC / DC is uploaded to the energy management system; The MMS network switch obtains photovoltaic DC / DC data from the energy management system.

9. The control method according to claim 6, It is characterized in that The method further comprises: The MMS network switch obtains data from the energy storage watt-hour meter and the transformer signal non-electricity measurement module through the energy management system, and uploads the data to the upper-level scheduling module.

10. The control method according to claim 6, It is characterized in that The energy storage watt-hour meter includes a DC energy storage watt-hour meter and an AC energy storage watt-hour meter.

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