Active control light storage power generation unit coordination controller

Abstract

The invention relates to an active control optical storage power generation unit coordination controller, which comprises a control management module used for collecting and uploading information of internal equipment of an optical storage power generation unit in real time, coordinating photovoltaic power generation and energy storage charging and discharging according to various received remote control instructions of a station control layer, and realizing optical storage combined power generation, peak regulation and primary frequency modulation; the step-up transformer is used for collecting low-voltage side current and voltage of the step-up transformer in real time; and the photovoltaic power generation unit is used for automatically setting a dynamic output control threshold value of the photovoltaic power generation unit in situ according to different weather conditions according to a photovoltaic output value acquired in real time, and realizing photovoltaic power generation by taking the threshold value as an instruction. According to the invention, the problems of large calculation amount, high configuration requirement, communication channel blockage, long response time, poor control precision and the like of the optical storage cooperative control system configured in the photovoltaic power station for acquiring and controlling the inverter and the energy storage equipment in each optical storage power generation unit are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic storage equipment, and in particular relates to an actively controlled photovoltaic storage power generation unit coordination controller. Background Art

[0002] The photovoltaic power generation unit is a basic power generation unit that installs energy storage equipment (including converters, batteries, battery BMS, auxiliary equipment, etc.) in a photovoltaic array (including photovoltaic modules, inverters, brackets, etc.) and uses photovoltaic AC coupling boosting or photovoltaic DC coupling inverter boosting. To achieve photovoltaic and energy storage combined operation, the current control method is as follows:

[0003] (1) A photovoltaic storage cooperative control system (or device) is configured at the station control layer of the photovoltaic power station to collect information about the inverter and energy storage equipment inside each photovoltaic storage power generation unit, and control the inverter power generation and energy storage charging and discharging of each unit according to instructions from the monitoring system (including the AGC / AVC system) and the primary frequency modulation system, so that the overall output of the power generation unit is controlled within the rated capacity of its step-up transformer;

[0004] (2) Configure an on-site communication control device in the photovoltaic power generation unit, and configure an energy storage MEU device (i.e., an energy storage system energy management device with protocol conversion and control functions) in the energy storage equipment. The communication control device uniformly collects and uploads information from each device in the photovoltaic power generation unit, receives instructions from each control system at the station control layer, and can also set control strategies locally. According to remote control instructions or local instructions, the inverter power generation and energy storage charging and discharging are coordinated and controlled. The overall output of the photovoltaic power generation unit is controlled within the rated capacity of its step-up transformer.

[0005] The above photovoltaic energy storage cooperative control system (or device) adopts remote control command mode to directly collect and separately control the inverter and energy storage converter inside each photovoltaic energy storage power generation unit. However, it is limited by the hardware configuration of the cooperative control system (or device), the huge amount of data collection and calculation, and inconsistent communication protocols. The actual operation effect is not good, the calculation amount is large, the communication is jammed, and the control response is delayed.

[0006] Disadvantages of existing technology

[0007] (1) The station control layer directly collects and controls the inverter and energy storage converter of each photovoltaic power generation unit.

[0008] Long response time: When the station control layer directly collects information from each photovoltaic power generation unit in the station, the huge amount of data will place higher requirements on the hardware performance and software control capabilities of the station control layer equipment. Since a control system (or device) needs to control the inverters and energy storage converters of dozens or even hundreds of photovoltaic power generation units to run simultaneously, the overall closed-loop operation time from data collection (including protocol conversion), logical judgment, command issuance to on-site response and execution will be as long as tens of seconds, which may cause energy storage counter-regulation and fail to bring into play the advantage of rapid energy storage regulation.

[0009] Poor control accuracy: Since the information of the inverter and energy storage is collected separately, and the inverter output and energy storage charging and discharging are controlled independently, the time for uploading and adjusting the response of the two parts of the 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.

[0010] Single control mode: The existing AGC / AVC system at the station control layer can only use the rated capacity of the step-up 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. Because the daily maximum output threshold of the grid connection point cannot be dynamically adjusted according to the actual weather, the energy storage utilization rate is low in cloudy weather and the energy storage does not work in rainy weather. At the same time, the output threshold issued by the existing AGC / AVC only considers the photovoltaic output and does not consider the role of energy storage, which makes the utilization rate of energy storage lower in actual operation.

[0011] (2) Configure the ground communication control device for the photovoltaic power generation unit to uniformly collect and upload the inverter and energy storage information, and coordinate the control of the inverter output and the charging and discharging of the energy storage converter according to the instructions issued by the station control layer.

[0012] The communication control device has poor control performance: the current communication control device is upgraded by adding control functions to the original inverter data acquisition device. When the hardware remains unchanged, the addition of control functions reveals that its computing power, control algorithm, data transmission and other performance cannot meet the safe and stable operation requirements of the photovoltaic storage power generation unit. First, the photovoltaic storage coordinated control capability is poor. When the light changes drastically, the total output control is unstable, and when the capacity of the step-up transformer is exceeded, the transformer overcurrent or overload protection is activated; second, the photovoltaic storage output control threshold is single, and the local control strategy cannot dynamically adjust the output control threshold according to different weather conditions, resulting in the energy storage not working or working less on cloudy or overcast days, and the effect of smoothing fluctuations and shaving peaks and filling valleys cannot be achieved, resulting in low energy storage utilization rate.

[0013] Energy storage EMU device affects control response and execution: Usually, the inverter and energy storage equipment are provided by two manufacturers. The communication control device is basically provided by the inverter manufacturer together. It uses the same internal Modbus protocol. The communication control device can directly collect information from each inverter. The data transmission speed is fast and can basically guarantee a closed loop within 60ms. However, the communication control device is limited by its communication protocol conversion function and cannot directly collect information from the energy storage converter and battery BMS. Therefore, it is necessary to configure a separate energy storage EMU device in the energy storage device, which uniformly collects energy storage equipment information (including energy storage converter, battery BMS, meter, environmental control, fire protection, etc.) and converts it into protocol information that the communication control device can receive, and at the same time receives the power command issued by the communication control device after protocol conversion. Due to the influence of protocol conversion delay, the command issued by the communication control device to the energy storage converter via the energy storage EMU device has a delay of about 6 to 8 seconds from issuance and receipt to completion of execution. The delay of the energy storage PCS after execution and feedback to the communication control device is also about 6 to 8 seconds. The above time delays cause problems such as slow energy storage response and poor control accuracy of combined photovoltaic and energy storage output.

[0014] The communication control device cannot directly collect the current and voltage signals on the low-voltage side of the step-up transformer: The communication control device supporting the inverter uses communication to collect the information of the inverter and control the overall inverter output, and there is no interface for directly collecting electrical signals. In order to ensure the stable operation of the photovoltaic power generation unit, the communication control device needs to collect the current and voltage signals on the low-voltage side of the step-up transformer of the photovoltaic power generation unit in real time as the electrical criterion for the photovoltaic and storage joint operation control strategy. However, due to the functional limitations of the data acquisition device, the upgraded communication control device cannot directly collect electrical signals. At present, the step-up transformer measurement and control device is collected through communication to obtain the electrical information on the low-voltage side of the step-up transformer. This method has the problem of slow data transmission, which is also a reason for the slow overall response and poor controllability of the photovoltaic power generation unit. In addition, when the step-up transformer measurement and control device fails or shuts down, and the judgment criteria of the photovoltaic operation control strategy disappear when the communication fails, it will also cause uncontrolled tripping.

[0015] The communication control device cannot independently control each energy storage inverter, and the energy storage EMU device cannot upload the SOC value of each energy storage battery BMS: For energy storage equipment equipped with multiple sets of energy storage inverters, the communication control device can only manage the energy storage charging and discharging as a whole through the energy storage EMU device, but cannot finely manage each energy storage inverter and its connected energy storage battery. For multiple inverters running in parallel, the deviation between the SOC values ​​of the corresponding batteries will gradually increase. At the same time, when any energy storage inverter exits operation, the SOC value reported by the energy storage EMU device is still sent according to the average SOC value of multiple BMSs, instead of sending the SOC value of the normally operating inverter, causing the photovoltaic storage control strategy to be affected by the SOC measurement value during execution, and deviations or errors in the energy storage charging and discharging control.

[0016] The communication control device cannot realize the local primary frequency and voltage regulation functions: due to reasons such as the device's software and hardware functions, communication protocol conversion, and control response delays, the photovoltaic power generation unit cannot realize the local primary frequency and voltage regulation functions. Summary of the invention

[0017] The purpose of the present invention is to provide an actively controlled photovoltaic power generation unit coordination controller in order to solve the above-mentioned problems.

[0018] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0019] An actively controlled photovoltaic power generation unit coordination controller, comprising:

[0020] Internal communication module, used for the information of internal equipment of direct solar storage power generation unit;

[0021] Analog input module, used to directly sample the voltage and current on the low-voltage side of the step-up transformer, divided into two inputs: protection and measurement;

[0022] The switch input module is used to access the protection action signal of the step-up transformer measurement and control device, and is used as an instantaneous lockout of the photovoltaic storage unit output when the transformer protection is actuated;

[0023] The switch output module is used to output multiple outputs, control the emergency power reduction of the equipment inside the photovoltaic power generation unit, and control the opening and closing of the circuit breaker on the low-voltage side of the step-up transformer and the circuit breaker of the energy storage equipment;

[0024] An upward communication module is used to respectively access the monitoring system and the primary frequency modulation system;

[0025] Human-machine interface module, including display screen interface, button interface, signal light interface and internal test communication interface;

[0026] The control management module is used to collect and upload information about the internal equipment of the photovoltaic and energy storage power generation unit in real time, coordinate photovoltaic power generation and energy storage charging and discharging according to various remote control instructions received from the station control layer, and realize photovoltaic and energy storage combined power generation, peak regulation, and primary frequency regulation; it is used to control the energy storage charging and discharging according to the current and voltage on the low-voltage side of the step-up transformer collected in real time, and realize primary frequency and voltage regulation if the current frequency and voltage exceed the dead zone set value; it is used to automatically set the dynamic photovoltaic and energy storage power generation unit output control threshold on-site according to different weather conditions based on the photovoltaic output value collected in real time, and use this threshold as an instruction to realize photovoltaic and energy storage combined power generation.

[0027] As a further optimization scheme of the present invention, the internal equipment of the light-storage power generation unit includes a photovoltaic inverter, a photovoltaic DC / DC, an energy storage converter, an energy storage DC / DC, a step-up transformer measurement and control device, an energy storage battery BMS, a meter, an energy storage environmental control and fire-fighting equipment.

[0028] As a further optimization solution of the present invention, the control strategy of photovoltaic and energy storage combined power generation when the station control layer issues control instructions includes:

[0029] The coordination controller receives the AGC power command of the station control layer, and adjusts the inverter and energy storage converter in real time according to the active power value Pagc issued by the AGC system, the maximum active power Pmax of the grid-connected point on the boost-to-low-voltage side, the real-time active power Ppcc of the grid-connected point on the boost-to-low-voltage side, the real-time active power Ppv of photovoltaic power, the active power Pcharge of energy storage, the active power Pdischarge of energy storage, and the energy storage SOC value:

[0030] When Ppcc>Pagc, and the energy storage meets the charging conditions, that is, SOC<upper limit value, the energy storage is controlled to charge. When the battery is charged to the upper limit of SOC setting, the energy storage is on standby. If the Pagc value does not change, the inverter is controlled to limit power generation so that Ppv'=Ppcc'=Pagc, where Ppv' represents the real-time active power of the photovoltaic power after real-time adjustment, and Ppcc' represents the real-time active power of the grid-connected point on the low-voltage side of the boost converter after real-time adjustment;

[0031] When Ppcc<Pagc, and the energy storage has the conditions for discharge, that is, SOC>lower limit value, the energy storage is controlled to discharge; when the battery is discharged to the lower limit of SOC setting, the energy storage is on standby, and if the Pagc value does not change, the inverter is controlled to generate electricity at the current maximum power Ppvmax=Ppccmax;

[0032] When Pagc>Pmax, Pmax is used as the maximum power command limit to adjust the inverter and energy storage in real time.

[0033] As a further optimization solution of the present invention, the peak load control strategy when the station control layer issues control instructions includes:

[0034] The coordination controller receives the peak-shaving power instruction from the station control layer, and adjusts the inverter and energy storage in real time according to the active power value Ptf issued by the peak-shaving, the maximum active power Pmax of the grid-connected point on the boost-to-low-voltage side, the real-time active power Ppcc of the grid-connected point on the boost-to-low-voltage side, the real-time active power Ppv of the photovoltaic power generation, the active power Pcharge of the energy storage, the active power Pdischarge of the energy storage, and the energy storage SOC value:

[0035] When Ppcc>Ptf, and the energy storage meets the charging conditions, that is, SOC<upper limit value, the energy storage is controlled to charge. When the battery is charged to the upper limit of SOC setting, the energy storage is on standby. If the Ptf value does not change, the inverter is controlled to limit power generation so that Ppv'=Ppcc'=Ptf, where Ppv' represents the real-time active power of the photovoltaic power after real-time adjustment, and Ppcc' represents the real-time active power of the grid-connected point on the low-voltage side of the boost converter after real-time adjustment;

[0036] When Ppcc<Ptf, and the energy storage meets the discharge conditions, that is, SOC>lower limit value, the energy storage is controlled to discharge. When the battery is discharged to the lower limit of SOC setting, the energy storage is on standby. If the Ptf value does not change, the inverter is controlled to generate electricity at the current maximum power Ppvmax=Ppccmax;

[0037] When Ptf>Pmax, Pmax is used as the maximum power command limit to adjust the inverter and energy storage in real time.

[0038] As a further optimization scheme of the present invention, the voltage regulation control strategy when the station control layer issues a control instruction includes:

[0039] The coordination controller receives the AVC power command from the station control layer, and adjusts the photovoltaic storage AC / DC, photovoltaic DC / DC and energy storage in real time according to the reactive power value Qavc, the maximum reactive power Qmax of the grid-connected point on the boost-to-low-voltage side, the real-time reactive power Qpcc of the grid-connected point on the boost-to-low-voltage side, the real-time reactive power Qpv of photovoltaic, the reactive power Qcharge of energy storage, the reactive power Qdischarge of energy storage, and the energy storage SOC value issued by the AVC system:

[0040] When Qpcc>Qavc, and the energy storage meets the charging conditions, that is, SOC<upper limit value, the energy storage charging is controlled. When the battery is charged to the upper limit of SOC setting, the energy storage is on standby. If the Qagc value does not change, the solar storage AC / DC and photovoltaic DC / DC are controlled to limit generation, so that Qpv′=Qpcc′=Qavc, where Qpv′ represents the real-time photovoltaic reactive power after real-time adjustment, and Qpcc′ represents the real-time reactive power of the boost-to-low-voltage side grid-connected point after real-time adjustment;

[0041] When Qpcc<Qagc, and the energy storage has the conditions for discharge, that is, SOC>lower limit value, the energy storage is controlled to discharge. When the battery is discharged to the lower limit of SOC setting, the energy storage is on standby. If the Qagc value does not change, the solar storage AC / DC and photovoltaic DC / DC are controlled to generate electricity at the current maximum power Qpvmax=Qpccmax;

[0042] When Qagc>Qmax, Qmax is used as the maximum power command limit to adjust the inverter and energy storage in real time.

[0043] As a further optimization scheme of the present invention, the primary frequency modulation control strategy when the station control layer issues a control instruction includes:

[0044] The coordination controller receives the power command of the primary frequency regulation control system at the station control layer, and adjusts the inverter and energy storage in real time according to the active power value Ptp issued by the primary frequency regulation, the maximum active power Pmax of the grid-connected point on the boost-to-low-voltage side, the real-time active power Ppcc of the grid-connected point on the boost-to-low-voltage side, the real-time active power Ppv of photovoltaic power, the active power Pcharge of energy storage, the active power Pdischarge of energy storage, and the energy storage SOC value:

[0045] When Ppcc>Ptp, and the energy storage meets the charging conditions, that is, SOC<upper limit value, the energy storage charging is controlled. When the battery is charged to the upper limit of SOC setting, the energy storage is on standby. If the Ptf value does not change, the photovoltaic storage AC / DC and photovoltaic DC / DC are controlled to limit generation, so that Ppv′=Ppcc′=Ptf, where Ppv' represents the real-time active power of photovoltaic after real-time adjustment, and Ppcc' represents the real-time active power of the boost-to-low-voltage side grid-connected point after real-time adjustment;

[0046] When Ppcc<Ptp, and the energy storage meets the discharge conditions, that is, SOC>lower limit value, the energy storage is controlled to discharge. When the battery is discharged to the lower limit of SOC setting, the energy storage is on standby. If the Ptf value does not change, the solar storage AC / DC and photovoltaic DC / DC are controlled to generate electricity at the current maximum power Ppvmax=Ppccmax;

[0047] When Ptp>Pmax, Pmax is used as the maximum power command limit to adjust the solar storage AC / DC, photovoltaic DC / DC and energy storage in real time.

[0048] As a further optimization scheme of the present invention, the control strategy of photovoltaic and energy storage combined power generation under the condition of issuing control instructions locally includes:

[0049] The coordination controller automatically and dynamically sets the power control threshold of the photovoltaic power generation unit grid connection point according to the collected photovoltaic output in three preset time periods every day;

[0050] The coordination controller dynamically sets the maximum output control threshold value Pdtagc of the photovoltaic power generation unit in each period of the day according to the maximum active power Pmax of the grid-connected point on the boost-to-low-voltage side, the real-time active power Ppcc of the grid-connected point on the boost-to-low-voltage side, the real-time active power Ppv of the photovoltaic power generation unit, the active power Pcharge of the energy storage unit, the active power Pdischarge of the energy storage unit, and the energy storage SOC value, and adjusts the inverter and energy storage unit in real time:

[0051] The first period: in the morning period, determine whether the photovoltaic power Ppv is greater than the preset percentage of Pmax. If so, use the preset percentage of Pmax as the output threshold Pdtagc for this period. Otherwise, use the preset percentage of Ppv for this period as the threshold Pdtagc for this period:

[0052] When Ppcc>Pdtagc, and the energy storage meets the charging conditions, that is, SOC<upper limit value, the energy storage is controlled to charge. When the battery is charged to the upper limit of SOC setting, the energy storage is on standby. If the Pdtagc value does not change, the inverter is controlled to limit power generation so that Ppv'=Ppcc′=Pdtagc, where Ppv' represents the real-time active power of the photovoltaic power after real-time adjustment, and Ppcc' represents the real-time active power of the grid-connected point on the low-voltage side of the boost converter after real-time adjustment;

[0053] When Ppcc<Pdtagc, and the energy storage has the conditions for discharge, that is, SOC>lower limit value, the energy storage is controlled to discharge; when the battery is discharged to the lower limit of SOC setting, the energy storage is on standby. If the Pdtagc value does not change, the inverter is controlled to generate electricity at the current maximum power Ppvmax=Ppccmax;

[0054] Second period: During the noon period, determine whether the photovoltaic power Ppv is greater than the preset percentage of Pmax. If so, use the preset percentage of Pma as the threshold value Pdtggc for this period. Otherwise, use the preset percentage of Ppv at that moment as the threshold value Pdtagc for this period.

[0055] The control strategy is the same as in the first period;

[0056] The third period: in the afternoon, determine whether the photovoltaic power Ppv is greater than the preset percentage of Pmax. If so, use the preset percentage of Pmax as the threshold value Pdtggc of this period. Otherwise, use the preset percentage of Ppv at this moment as the threshold value Pdtagc of this period.

[0057] The control strategy is the same as in the first period.

[0058] As a further optimization scheme of the present invention, the primary frequency modulation control strategy when the control instruction is issued locally includes:

[0059] The coordination controller calculates the grid connection point frequency by collecting the current and voltage on the boost-to-low voltage side, and calculates the active power deviation command Ptp according to the current frequency exceeding the set reference frequency dead zone range. At the same time, according to the maximum active power Pmax of the boost-to-low voltage side grid connection point, the real-time active power Ppcc of the boost-to-low voltage side grid connection point, the real-time active power Ppv of the photovoltaic power generation, the active power Pcharge of the energy storage that can be charged, the active power Pdischarge of the energy storage that can be discharged, and the energy storage SOC value, the inverter and energy storage are adjusted in real time:

[0060] When the frequency of the grid connection point is lower than the reference frequency and the frequency deviation exceeds the dead zone, the local frequency regulation command is to increase;

[0061] If Pdischarge>Ptp, the energy storage is controlled to discharge at the difference between the two values, so that Pdischarge'=Ptp, where Pdischarge' represents the active power that can be discharged by the energy storage after adjustment;

[0062] If Pdischarge<Ptp, control the inverter and energy storage to discharge at the current maximum power Pdischargemax+Ppvmax=Ppccmax;

[0063] When the grid connection point frequency is higher than the reference frequency and the frequency deviation exceeds the dead zone, the local frequency regulation command is to adjust downward:

[0064] If Pcharge>Ptp, the energy storage is controlled to be charged with the difference between the two, so that Pcharge'=Ptp, where Pcharge' represents the adjusted active power of the energy storage;

[0065] If Pcharge<Ptp, the energy storage is controlled to charge at the current maximum power Pchargemax, and the inverter is controlled to limit power generation so that Pchargemax+Ppv'=Ptp.

[0066] As a further optimization scheme of the present invention, the voltage regulation control strategy when the control instruction is issued locally includes:

[0067] The coordinated controller collects the voltage on the boost-to-low voltage side, calculates the reactive power deviation command Qty according to the current voltage exceeding the set reference voltage dead zone range, and adjusts the inverter and energy storage in real time according to the maximum reactive power Qmax of the boost-to-low voltage side grid-connected point, the real-time reactive power Qpcc of the boost-to-low voltage side grid-connected point, the real-time reactive power Qpv of the photovoltaic power generation, the reactive power Qcharge of the energy storage that can be charged, the reactive power Qdischarge of the energy storage that can be discharged, and the energy storage SOC value:

[0068] When the grid-connected point voltage is lower than the reference voltage and the voltage deviation exceeds the dead zone, the local voltage regulation command is to increase:

[0069] If Qdischarge>Qty, control the energy storage to discharge at the difference between the two, so that Qdischarge′=Qty; if Qdischarge<Qty, control the inverter and energy storage to discharge at the current maximum power Qdischargemax+Qpvmax=Qpccmax;

[0070] When the grid-connected point voltage is higher than the reference voltage and the voltage deviation exceeds the dead zone, the local voltage regulation command is to adjust downward:

[0071] If Qcharge>Qty, the energy storage is controlled to be charged with the difference between the two, so that Qcharge′=Qty, where Qcharge′ represents the adjusted chargeable reactive power of the energy storage; if Qcharge<Qty, the energy storage is controlled to be charged with the current maximum power Qchargemax, and the inverter is controlled to limit power generation, so that Qchargemax+Qpv′=Qty, where Qpv′ represents the adjusted real-time reactive power of the photovoltaic power plant.

[0072] The beneficial effects of the present invention are:

[0073] The present invention solves the problems of configuring a photovoltaic storage cooperative control system (or device) in a photovoltaic power station to collect and control the inverter and energy storage equipment inside each photovoltaic storage power generation unit, such as large calculation amount, high configuration requirements, communication channel jams, long response time, poor control accuracy, etc.

[0074] 2. The coordination controller configured on-site in the photovoltaic and storage power generation unit (a communication control device upgraded from the inverter data acquisition device by adding control functions, without direct acquisition and direct control functions) has been solved. In the photovoltaic and storage joint operation after receiving station control layer instructions or local control instructions, the problems of long adjustment response time, poor control accuracy, single control mode, and poor operation stability have been solved. At the same time, the problem of lack of local active primary frequency and voltage regulation functions caused by the above problems has been solved;

[0075] 3. It solves the problem that when the control layer of the photovoltaic power station cannot set the output control threshold of the combined operation of light and storage (photovoltaic storage AGC), the light and storage output control threshold remains unchanged, the local control strategy cannot dynamically adjust the control threshold according to different weather conditions, and in cloudy or rainy weather, the energy storage utilization rate is low and the light output fluctuates greatly. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] Figure 1 It is the overall structural diagram of the present invention;

[0077] Figure 2 It is a communication control schematic diagram of a photovoltaic power generation unit in an AC coupling mode suitable for configuring a centralized or distributed inverter in an embodiment of the present invention;

[0078] Figure 3 It is a communication control schematic diagram of a photovoltaic power generation system in an AC coupling mode suitable for configuring a string inverter in an embodiment of the present invention; Figure 4 It is a communication control schematic diagram of a photovoltaic storage power generation system in a DC coupling mode suitable for configuring a photovoltaic storage integrated machine in an embodiment of the present invention. DETAILED DESCRIPTION

[0079] The present application is further described in detail below in conjunction with the accompanying drawings. It is necessary to point out here that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technical personnel in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0080] Photovoltaic storage power generation unit: used as the basic power generation unit of photovoltaic power stations. In the photovoltaic array, the energy storage device is connected in parallel with the photovoltaic power generation system (including AC coupling and DC coupling), and the voltage is boosted by the transformer to a power supply that meets the frequency and voltage requirements of the power grid.

[0081] Coordination controller: Each photovoltaic power generation unit is equipped with one on-site, which is used as the on-site control and communication equipment of the photovoltaic power generation unit to collect, process and upload information from inverters, energy storage equipment (including converters, energy storage battery BMS, environmental control system, fire protection system, etc.), step-up transformers (equipped with transformer measurement and control devices), meters (electricity meters) and other systems (such as tracking bracket systems, online test systems, etc.), and send station control layer or local control instructions to coordinate and control the joint operation of inverters and energy storage converters. Functions include:

[0082] (1) The coordination controller receives remote control commands from various control systems at the station control layer of the photovoltaic power station, and coordinates and controls the inverter output of the photovoltaic power generation unit and the charging and discharging of the energy storage equipment according to the control commands;

[0083] (2) The coordination controller automatically controls the inverter output of the photovoltaic power generation unit and the charging and discharging of the energy storage device based on the current and voltage collected on the low-voltage side of the step-up transformer, and actively realizes primary frequency and voltage regulation;

[0084] (3) When the station control layer does not have the combined output control threshold of light generation and energy storage (solar-storage AGC) according to different weather conditions, the coordinated controller dynamically sets the output control threshold of the photovoltaic-storage power generation unit on-site according to the photovoltaic output collected in real time, and coordinates the control of the inverter output and the charging and discharging of the energy storage equipment according to the control threshold.

[0085] like Figure 1 As shown, an actively controlled photovoltaic storage power generation unit coordination controller is suitable for photovoltaic storage AC coupling and photovoltaic storage DC coupling. It can accept remote control instructions from the station control layer to realize photovoltaic storage combined power generation, and can also dynamically control photovoltaic storage combined power generation locally according to different weather conditions, and realize primary frequency regulation and voltage regulation at the same time. While ensuring the safe, stable, efficient and reliable operation of the photovoltaic storage power generation unit, it can give full play to the regulating role of energy storage in photovoltaic power generation, including:

[0086] The coordination controller is equipped with an internal communication module, which can directly acquire multiple photovoltaic inverters (data acquisition devices when string inverters are configured), multiple photovoltaic DC / DCs, multiple energy storage converters, multiple energy storage DC / DCs, multiple energy storage battery BMSs, booster transformer measurement and control devices, multiple electric energy meters, energy storage fire protection systems, energy storage environmental control systems, tracking bracket control systems, etc. It supports communication protocols such as IEC104 and ModBus, and supports IEC 61850 standards.

[0087] The coordination controller is equipped with an analog input module, which directly samples the low-voltage side voltage (taken from the voltage transformer, the secondary side voltage is 100V) and current (taken from the current transformer, the secondary side current is 5A) of the step-up transformer, which is divided into two inputs: protection and measurement.

[0088] The coordination controller is equipped with a switch input module, which is connected to the protection action signal of the step-up transformer measurement and control device (in the form of dry contacts) and used as an instantaneous lockout of the photovoltaic storage unit output when the transformer protection is actuated;

[0089] The coordination controller is equipped with a switch output module, which outputs multiple outputs (in the form of dry contacts) to control the photovoltaic inverter (or data acquisition device), photovoltaic DC / DC, energy storage converter, and energy storage DC / DC emergency power reduction. It can also control the low-voltage side circuit breaker of the boost transformer and the opening and closing of the circuit breaker of the energy storage equipment.

[0090] The coordination controller is equipped with an upward communication module, which is connected to the monitoring system (including AGC / AVC system), primary frequency modulation system, etc. Various communication interfaces are independent of each other, supporting communication protocols such as IEC103 and IEC104, and supporting IEC 61850 standards;

[0091] The coordination controller is configured with a human-machine interface module, which includes a display screen, buttons, signal lights, internal test communication interface, etc.

[0092] The coordination controller configures the control management module, and its functions are as follows:

[0093] (1) Collect and upload the internal information of the photovoltaic and energy storage power generation units in real time, coordinate photovoltaic power generation and energy storage charging and discharging according to various remote control instructions received from the station control layer, and realize photovoltaic and energy storage combined power generation (AGC / AVC), peak load regulation, primary frequency regulation and other functions;

[0094] (2) Based on the current and voltage on the low-voltage side of the step-up transformer collected in real time, if the current frequency and voltage exceed the dead zone set value, the energy storage charging and discharging is controlled to achieve the primary frequency and voltage regulation function;

[0095] (3) Based on the real-time collected photovoltaic output value, the dynamic photovoltaic storage power generation unit output control threshold is automatically set on-site according to different weather conditions, and this threshold is used as an instruction to realize photovoltaic storage combined power generation.

[0096] The coordination controller is an embedded device with the function of recording waveforms in the event of an accident. The working power supply voltage is AC220V.

[0097] Communication control description of photovoltaic power generation unit

[0098] 1. Configure the photovoltaic storage AC coupling solution of centralized (or distributed) inverters, such as Figure 2 As shown,

[0099] (1) Station control layer control system configuration description:

[0100] 1) Monitoring system (including AGC / AVC system), such as system A in the figure;

[0101] 2) Primary frequency modulation system, such as system B in the figure;

[0102] 3) Other control systems, such as system C in the figure.

[0103] (2) Configuration description of photovoltaic power generation unit equipment:

[0104] 1) The centralized (or distributed) inverter, energy storage converter, and energy storage battery are centrally arranged, and the inverter and energy storage converter are connected in parallel to the boost-to-low voltage side in AC coupling mode;

[0105] 2) The step-up transformer is equipped with a box transformer measurement and control device, each battery system is equipped with a BMS, and the photovoltaic storage power generation unit is equipped with a coordination controller;

[0106] 3) Meters (electricity meters) are configured on the AC side of the inverter and energy storage converter, as well as on the step-up to low voltage side;

[0107] 4) Other systems: such as tracking support system, online testing system, etc.

[0108] (3) Control flow description:

[0109] 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 IEC103, IEC104, and IEC61850, as shown by the light green line in the figure above;

[0110] 2) The coordination controller directly collects data from the photovoltaic inverter, energy storage converter, battery BMS, boost transformer measurement and control device, energy meter, energy storage fire protection system, energy storage environmental control system, tracking bracket control system, etc. inside the photovoltaic power generation unit, and supports IEC104, ModBus, and IEC 61850, as shown by the green line in the figure above;

[0111] 3) The coordination controller directly collects the voltage and current analog quantities on the boost-to-low voltage side, as shown by the yellow line in the figure above;

[0112] 4) The coordination controller is connected to the action signal (dry contact) of the boost transformer measurement and control device (including protection function), as shown by the blue line in the figure above;

[0113] 5) The coordinated controller outputs multiple outputs (dry contacts) to control the inverter and energy storage converter to reduce power urgently in case of transformer failure. It can also control the opening and closing of the circuit breaker on the low voltage side of the boost transformer and the circuit breaker of the energy storage device, as shown by the red line in the figure above;

[0114] 6) 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 remote control instructions, and realize photovoltaic and energy storage combined power generation, peak regulation, primary frequency regulation and other functions; it can also control the energy storage charging and discharging to realize the primary frequency and voltage regulation functions based on the real-time collected current and voltage on the low-voltage side of the step-up transformer if the current frequency and voltage exceed the dead zone set value; 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 use this threshold as an instruction to realize photovoltaic and energy storage combined power generation.

[0115] 2. Configure the photovoltaic storage AC coupling solution of the string inverter, such as Figure 3 As shown:

[0116] (1) Station control layer control system configuration description: Figure 2 Consistent.

[0117] (2) Configuration description of photovoltaic power generation unit equipment:

[0118] 1) The string inverter, energy storage converter, energy storage battery, etc. are centrally arranged (the string inverter is manufactured in an integrated manner and can also be arranged in a decentralized manner). The inverter and energy storage converter are connected in parallel to the boost-to-low voltage side in AC coupling mode;

[0119] 2) The step-up transformer is equipped with a box transformer measurement and control device, the string inverter is equipped with a data acquisition device, each battery system is equipped with a BMS, and the photovoltaic storage power generation unit is equipped with a coordination controller;

[0120] 3) Meters (electricity meters) are configured on the AC side of the inverter and energy storage converter, as well as on the step-up to low voltage side;

[0121] 4) Other systems: such as tracking support system, online testing system, etc.

[0122] (3) Control flow description:

[0123] 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 IEC103, IEC104, and IEC61850, as shown by the light green line in the figure above;

[0124] 2) The coordination controller directly collects data from the inverter data acquisition device, energy storage converter, battery BMS, boost transformer measurement and control device, energy meter, energy storage fire protection system, energy storage environmental control system, tracking bracket control system, etc. inside the photovoltaic power generation unit, and supports IEC104, ModBus, and IEC 61850, as shown by the green line in the figure above;

[0125] 3) The coordination controller directly collects the voltage and current analog quantities on the boost-to-low voltage side, as shown by the yellow line in the figure above;

[0126] 4) The coordination controller is connected to the action signal (dry contact) of the boost transformer measurement and control device (including protection function), as shown by the blue line in the figure;

[0127] 5) Coordinate the controller to output multiple outputs (dry contacts), control the inverter (realized through the data acquisition device), and the energy storage converter to reduce power urgently in the event of a transformer failure. It can also control the opening and closing of the circuit breaker on the low-voltage side of the boost transformer and the circuit breaker of the energy storage device, as shown by the red line in the figure above;

[0128] 6) 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 remote control instructions, and realize photovoltaic and energy storage combined power generation, peak regulation, primary frequency regulation and other functions; it can also control the energy storage charging and discharging to realize the primary frequency and voltage regulation functions based on the real-time collected current and voltage on the low-voltage side of the step-up transformer if the current frequency and voltage exceed the dead zone set value; 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 use this threshold as an instruction to realize photovoltaic and energy storage combined power generation.

[0129] 3. Configure the photovoltaic storage DC coupling solution of the photovoltaic storage integrated machine, such as Figure 4 As shown:

[0130] (1) Station control layer control system configuration description: Figure 2 Consistent.

[0131] (2) Configuration description of photovoltaic power generation unit equipment:

[0132] 1) The photovoltaic storage converter, photovoltaic DC / DC, energy storage DC / DC, and energy storage battery are centrally arranged. The photovoltaic DC / DC and energy storage DC / DC are connected in parallel to the DC side of the photovoltaic storage converter in DC coupling mode, and the AC side of the photovoltaic storage converter is connected to the boost-to-low voltage side;

[0133] 2) The step-up transformer is equipped with a box transformer measurement and control device, and the photovoltaic power generation unit is equipped with a coordination controller;

[0134] 3) Meters (electricity meters) are configured on the DC bus side of the photovoltaic DC / DC and energy storage DC / DC, as well as on the step-up and low-voltage side;

[0135] 4) Other systems: such as tracking support system, online testing system, etc.

[0136] (3) Control flow description:

[0137] 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 IEC103, IEC104, and IEC61850, as shown by the light green line in the figure above;

[0138] 2) The coordination controller directly collects data from the photovoltaic storage converter, photovoltaic DC / DC, energy storage DC / DC, battery BMS, boost transformer measurement and control device, energy meter, energy storage fire protection system, energy storage environmental control system, tracking bracket control system, etc. inside the photovoltaic storage power generation unit, and supports IEC104, ModBus, and IEC 61850, as shown by the green line in the figure above;

[0139] 3) The coordination controller directly collects the voltage and current analog quantities on the boost-to-low voltage side, as shown by the yellow line in the figure above;

[0140] 4) The coordination controller is connected to the action signal (dry contact) of the boost transformer measurement and control device (including protection function), as shown by the blue line in the figure above;

[0141] 5) The coordinated controller outputs multiple outputs (dry contacts) to control the photovoltaic storage converter and energy storage DC / DC to reduce power urgently in the event of a transformer failure. It can also control the opening and closing of the circuit breaker on the low-voltage side of the boost transformer and the circuit breaker of the energy storage device, as shown by the red line in the figure above;

[0142] 6) 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 remote control instructions, and realize photovoltaic and energy storage combined power generation, peak regulation, primary frequency regulation and other functions; it can also control the energy storage charging and discharging to realize the primary frequency and voltage regulation functions based on the real-time collected current and voltage on the low-voltage side of the step-up transformer if the current frequency and voltage exceed the dead zone set value; 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 use this threshold as an instruction to realize photovoltaic and energy storage combined power generation.

[0143] 3. Control strategy description

[0144] The above three photovoltaic storage coupling modes are basically the same in terms of control principles. The following takes the photovoltaic storage power generation unit in AC coupling mode as an example to explain its operation control strategy.

[0145] The coordination controller can automatically execute the corresponding control strategy according to different operating conditions. The coordination controller can choose remote mode or local mode.

[0146] 1. The station control layer issues control instructions

[0147] (1) Solar-storage combined power generation

[0148] The coordination controller receives the AGC power command of the station control layer through the monitoring communication interface, and adjusts the inverter and energy storage converter in real time according to the active power value Pagc issued by the AGC system, the maximum active power Pmax of the grid-connected point on the low-voltage side of the boost transformer (1.1 times the rated capacity of the boost transformer), the real-time active power Ppcc of the grid-connected point on the low-voltage side of the boost transformer, the real-time active power Ppv of photovoltaic power, the chargeable active power Pcharge of energy storage, the dischargeable active power Pdischarge of energy storage, and the energy storage SOC value.

[0149] 1) When Ppcc>Pagc, and the energy storage has the charging conditions (SOC<upper limit value), control the energy storage charging (absorb active power), and when the battery is charged to the upper limit of SOC setting, the energy storage is on standby. If the Pagc value does not change, control the inverter to limit power generation (limit active power generation) so that Ppv'=Ppcc′=Pagc; Ppv' represents the real-time active power of photovoltaic power after real-time adjustment, and Ppcc' represents the real-time active power of the grid-connected point on the low-voltage side of the boost converter after real-time adjustment;

[0150] 2) When Ppcc<Pagc, and the energy storage meets the discharge conditions (SOC>lower limit value), control the energy storage to discharge (release active power). When the battery is discharged to the lower limit of SOC setting, the energy storage is on standby. If the Pagc value does not change, control the inverter to generate electricity (release active power) at the current maximum power Ppvmax=Ppccmax;

[0151] 3) When Pagc>Pmax, Pmax is used as the maximum power command limit to adjust the inverter and energy storage in real time.

[0152] (2) Peak Load Shaving

[0153] The coordination controller receives the peak-shaving power instruction from the station control layer through the monitoring communication interface, and adjusts the inverter and energy storage in real time according to the active power value Ptf issued by the peak-shaving, the maximum active power Pmax of the grid-connected point on the low-voltage side of the boost transformer (1.1 times the rated capacity of the boost transformer), the real-time active power Ppcc of the grid-connected point on the low-voltage side of the boost transformer, the real-time active power Ppv of the photovoltaic power generation, the chargeable active power Pcharge of the energy storage, the dischargeable active power Pdischarge of the energy storage, and the energy storage SOC value.

[0154] 1) When Ppcc>Ptf, and the energy storage has the charging conditions (SOC<upper limit value), control the energy storage to charge (absorb active power), and when the battery is charged to the SOC set upper limit, the energy storage is on standby. If the Ptf value does not change, control the inverter to limit power generation (limit active power generation) so that Ppv'=Ppcc'=Ptf;

[0155] 2) When Ppcc<Ptf, and the energy storage meets the discharge conditions (SOC>lower limit value), the energy storage is controlled to discharge (release active power). When the battery is discharged to the lower limit of SOC setting, the energy storage is on standby. If the Ptf value does not change, the inverter is controlled to generate electricity (release active power) at the current maximum power Ppvmax=Ppccmax;

[0156] 3) When Ptf>Pmax, Pmax is used as the maximum power command limit to adjust the inverter and energy storage in real time.

[0157] (3) Voltage regulation

[0158] The coordination controller receives the AVC power command of the station control layer through the monitoring communication interface, and adjusts the photovoltaic storage AC / DC, photovoltaic DC / DC and energy storage in real time according to the reactive power value Qavc issued by the AVC system, the maximum reactive power Qmax of the grid-connected point on the low-voltage side of the boost transformer (1.1 times the rated capacity of the boost transformer), the real-time reactive power Qpcc of the grid-connected point on the low-voltage side of the boost transformer, the real-time reactive power Qpv of the photovoltaic power generation, the chargeable reactive power Qcharge of the energy storage, the dischargeable reactive power Qdischarge of the energy storage and the energy storage SOC value.

[0159] 1) When Qpcc>Qavc, and the energy storage meets the charging conditions (SOC<upper limit), control the energy storage charging (absorb reactive power), and when the battery is charged to the upper limit of the SOC setting, the energy storage is on standby. If the Qagc value does not change, control the photovoltaic storage AC / DC and photovoltaic DC / DC to limit generation (limit reactive power generation) so that Qpv′=Qpcc′=Qavc; Qpv′ represents the real-time photovoltaic reactive power after real-time adjustment, and Qpcc′ represents the real-time reactive power of the boost-to-low-voltage side grid-connected point after real-time adjustment;

[0160] 2) When Qpcc<Qagc, and the energy storage meets the discharge conditions (SOC>lower limit value), control the energy storage to discharge (release reactive power), and when the battery is discharged to the lower limit of SOC setting, the energy storage is on standby. If the Qagc value does not change, control the solar storage AC / DC and photovoltaic DC / DC to generate electricity (release reactive power) at the current maximum power Qpvmax=Qpccmax;

[0161] 3) When Qagc>Qmax, Qmax is used as the maximum power command limit to adjust the inverter and energy storage in real time.

[0162] (4) Primary frequency modulation

[0163] The coordination controller receives power instructions from the primary frequency regulation control system of the station control layer through the fast control communication interface (the primary frequency regulation control system collects the current and voltage of the grid connection point in real time to calculate the frequency, and issues frequency regulation instructions when it exceeds the frequency regulation dead zone), and adjusts the inverter and energy storage in real time according to the active power value Ptp issued by the primary frequency regulation, the maximum active power Pmax of the grid connection point on the low-voltage side of the boost transformer (1.1 times the rated capacity of the boost transformer), the real-time active power Ppcc of the grid connection point on the low-voltage side of the boost transformer, the real-time active power Ppv of photovoltaic power generation, the chargeable active power Pcharge of energy storage, the dischargeable active power Pdischarge of energy storage, and the energy storage SOC value.

[0164] 1) When Ppcc>Ptp, and the energy storage meets the charging conditions (SOC<upper limit value), control the energy storage charging (absorb active power), and when the battery is charged to the upper limit of SOC setting, the energy storage is on standby. If the Ptf value does not change, control the solar storage AC / DC and photovoltaic DC / DC to limit generation (limit active power generation) so that Ppv′=Ppcc′=Ptf;

[0165] 2) When Ppcc<Ptp, and the energy storage meets the discharge conditions (SOC>lower limit value), control the energy storage to discharge (release active power), and when the battery is discharged to the lower limit of SOC setting, the energy storage is on standby. If the Ptf value does not change, control the solar storage AC / DC and photovoltaic DC / DC to generate electricity (release active power) at the current maximum power Ppvmax=Ppccmax;

[0166] 3) When Ptp>Pmax, Pmax is used as the maximum power command limit to adjust the solar storage AC / DC, photovoltaic DC / DC and energy storage in real time.

[0167] 2. Locally send control instructions

[0168] (1) Solar-storage combined power generation

[0169] When issuing output instructions for the luminous and energy-storage power generation units under the station control layer AGC system, if weather factors are not taken into account and the energy storage configuration in the photovoltaic array is not considered, the local luminous and energy-storage combined power generation mode is preferentially adopted.

[0170] The coordination controller automatically and dynamically sets (the setting method is adjustable) the power control threshold of the photovoltaic power generation unit grid connection point according to the collected photovoltaic output (determined by weather and irradiation) in three time periods every day (the number of time periods and the start and end time of each time period can be set). The local mode can be put into operation and withdrawn. When the station control layer realizes the dynamic threshold adjustment function in the later stage, this mode will be turned off and the photovoltaic power generation will be executed according to the remote control command power instead.

[0171] The coordination controller dynamically sets the maximum output control threshold value Pdtagc (Pdtagc≤Pmax) of the photovoltaic power generation unit in each period of the day according to the maximum active power Pmax of the grid-connected point on the low-voltage side of the boost transformer (1.1 times the rated capacity of the boost transformer), the real-time active power Ppcc of the grid-connected point on the low-voltage side of the boost transformer, the real-time active power of photovoltaic power generation Ppv, the chargeable active power Pcharge of the energy storage, the dischargeable active power Pdischarge of the energy storage, and the energy storage SOC value, and makes real-time adjustments to the inverter and energy storage.

[0172] The first period: the morning period 6:00-8:59 (the period can be set), at 6:00 (can be set), determine whether the photovoltaic power Ppv is greater than 10% Pmax (can be set), if so, use 80% Pmax (can be set) as the output threshold Pdtagc of this period, otherwise, use 40% of Ppv at that moment (can be set) as the threshold Pdtagc of this period.

[0173] 1) When Ppcc>Pdtagc, and the energy storage has the charging conditions (SOC<upper limit value), control the energy storage to charge (absorb active power), and when the battery is charged to the SOC set upper limit, the energy storage is on standby. If the Pdtagc value does not change, control the inverter to limit power generation (limit active power generation), so that Ppv'=Ppcc'=Pdtagc;

[0174] 2) When Ppcc<Pdtagc, and the energy storage meets the discharge conditions (SOC>lower limit value), control the energy storage to discharge (release active power). When the battery is discharged to the lower limit of SOC setting, the energy storage is on standby. If the Pdtagc value does not change, control the inverter to generate electricity (release active power) at the current maximum power Ppvmax=Ppccmax.

[0175] The second period: noon period 9:00-14:59 (time period can be set), at 9:00 (can be set), determine whether the photovoltaic power Ppv is greater than 100% Pmax (can be set), if so, use 100% Pma (can be set) as the threshold value Pdtggc of this period, otherwise, 80% of Ppv at that moment (can be set) is used as the threshold value Pdtagc of this period.

[0176] The control strategy is the same as that of the first period.

[0177] The third period: afternoon period 15:00-19:00 (time period can be set), at 15:00 (can be set), determine whether the photovoltaic power Ppv is greater than 80% Pmax (can be set), if so, use 60% Pmax (can be set) as the threshold value Pdtggc of this period, otherwise, use 60% of Ppv at that moment (can be set) as the threshold value Pdtagc of this period.

[0178] The control strategy is the same as the first period.

[0179] (2) Primary frequency modulation

[0180] The coordination controller calculates the grid connection point frequency by collecting the current and voltage on the low-voltage side of the boost transformer, and calculates the active power deviation command Ptp based on the current frequency exceeding the set reference frequency dead zone range (±0.05Hz, parameter can be set). At the same time, according to the maximum active power Pmax of the grid connection point on the low-voltage side of the boost transformer (1.1 times the rated capacity of the boost transformer), the real-time active power Ppcc of the grid connection point on the low-voltage side of the boost transformer, the real-time active power Ppv of the photovoltaic power generation, the chargeable active power Pcharge of the energy storage, the dischargeable active power Pdischarge of the energy storage, and the energy storage SOC value, the inverter and energy storage are adjusted in real time.

[0181] 1) When the grid connection point frequency is lower than the reference frequency and the frequency deviation exceeds the dead zone, the local frequency regulation instruction is to increase.

[0182] If Pdischarge>Ptp, the energy storage is controlled to discharge (release active power) at the difference between the two, so that Pdischarge'=Ptp;

[0183] If Pdischarge<Ptp, control the inverter and energy storage to discharge (release active power) at the current maximum power Pdischargemax+Ppvmax=Ppccmax;

[0184] 2) When the frequency of the grid connection point is higher than the reference frequency and the frequency deviation exceeds the dead zone, the local frequency regulation command is to adjust downward.

[0185] If Pcharge>Ptp, the energy storage is controlled to charge with the difference between the two (absorbing active power) so that Pcharge'=Ptp;

[0186] If Pcharge<Ptp, the energy storage is controlled to charge at the current maximum power Pchargemax (absorbing active power), and the inverter is controlled to limit power generation (limit active power generation) so that Pchargemax+Ppv'=Ptp.

[0187] (3) Voltage regulation

[0188] The coordinated controller collects the voltage on the low-voltage side of the boost transformer, and calculates the reactive power deviation command Qty based on the current voltage exceeding the set reference voltage dead zone range (parameters can be set). At the same time, the inverter and energy storage are adjusted in real time based on the maximum reactive power Qmax of the grid-connected point on the low-voltage side of the boost transformer (1.1 times the rated capacity of the boost transformer), the real-time reactive power Qpcc of the grid-connected point on the low-voltage side of the boost transformer, the real-time reactive power Qpv of the photovoltaic power generation, the chargeable reactive power Qcharge of the energy storage, the dischargeable reactive power Qdischarge of the energy storage, and the energy storage SOC value.

[0189] 1) When the grid connection point voltage is lower than the reference voltage and the voltage deviation exceeds the dead zone, the local voltage regulation command is to increase.

[0190] If Qdischarge>Qty, the energy storage is controlled to discharge (release reactive power) at the difference between the two, so that Qdischarge′=Qty; if Qdischarge<Qty, the inverter and energy storage are controlled to discharge (release reactive power) at the current maximum power Qdischargemax+Qpvmax=Qpccmax.

[0191] 2) When the grid connection point voltage is higher than the reference voltage and the voltage deviation exceeds the dead zone, the local voltage regulation command is to adjust downward.

[0192] If Qcharge>Qty, the energy storage is controlled to charge with the difference between the two (absorbing reactive power) so that Qcharge′=Qty; if Qcharge<Qty, the energy storage is controlled to charge with the current maximum power Qchargemax (absorbing reactive power), and at the same time the inverter is controlled to limit power generation (limit reactive power generation) so that Qchargemax+Qpv′=Qty.

[0193] The functions of the coordination controller provided by the present invention include:

[0194] 1. Directly collect current and voltage signals on the low-voltage side of the step-up transformer, and directly collect the equipment inside the photovoltaic power generation unit (including photovoltaic inverters or their data acquisition devices, photovoltaic DC / DC, energy storage converters, energy storage DC / DC, as well as step-up transformer measurement and control devices, energy storage battery BMS, meters, energy storage environmental control and fire-fighting equipment, other intelligent systems, etc.);

[0195] 2. The monitoring communication interface and the fast control communication interface are independent of each other, and receive control instructions from the photovoltaic power station station control layer monitoring system (including AGC / AVC system) and the primary frequency modulation system respectively;

[0196] 3. Based on the collected current and voltage signals on the low-voltage side of the step-up transformer, local automatic primary frequency and voltage regulation control is implemented;

[0197] 4. According to the real-time collected photovoltaic output, the output control threshold of the photovoltaic power generation unit is dynamically set on site;

[0198] 5. According to remote control commands and local commands, directly control the output of photovoltaic inverter (or photovoltaic DC / DC) and the charging and discharging of energy storage converter (or energy storage DC / DC).

[0199] The present invention configures a dedicated coordination controller for the photovoltaic power generation unit, and the coordination controller has an on-site active control function: considering that the inverter data collector has limited functions, it is no longer upgraded to be used as a communication control device, and it is still dedicated to inverter data collection and power generation control.

[0200] This invention is a photovoltaic power generation unit coordination controller, which can meet the safe, stable, efficient and reliable operation requirements of photovoltaic power generation units. The device has the following characteristics:

[0201] Supports AC coupling or DC coupling mode for photovoltaic storage;

[0202] Direct-source inverters or their data collectors, photovoltaic DC / DC, energy storage converters, energy storage DC / DC, battery BMS, meters, energy storage environmental control and fire protection systems, etc.;

[0203] Directly collect current and voltage signals from the low-voltage side of the step-up transformer;

[0204] Direct-controlled inverter or its data collector, photovoltaic DC / DC, energy storage converter, energy storage DC / DC; can control multiple energy storage converters to run in parallel, distribute the power of multiple converters evenly according to the SOC value of each battery pack, and balance the SOC value of each battery pack;

[0205] The upper monitoring communication interface and the fast control communication interface are independent, and can receive and quickly execute remote control commands of various control systems at the station control layer of the photovoltaic power station (including AGC / AVC commands and primary frequency modulation commands);

[0206] It has the function of local active primary frequency and voltage regulation. After exceeding the frequency and voltage regulation dead zone set value, it automatically controls the charging and discharging of energy storage to achieve rapid response of active frequency and voltage reactive power.

[0207] Based on the real-time collection of photovoltaic output, the dynamic output control threshold is automatically set on-site according to different weather conditions (using the output corresponding to irradiation) to avoid low energy storage utilization in cloudy weather and the inability to put the energy storage into operation in overcast weather, that is, in non-sunny weather, the utilization rate of energy storage is low and the energy storage is not effective in smoothing the volatility of photovoltaic output.

[0208] After the photovoltaic power generation unit is equipped with a dedicated coordination controller, it can safely, stably and efficiently realize functions such as joint power generation, peak load regulation, primary frequency regulation and voltage regulation.

[0209] The above embodiments only express several implementation methods of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention,

[0210] Several variations and improvements are made, all of which fall within the scope of protection of the present invention.

Claims

1. An actively controlled photovoltaic power generation unit coordination controller, characterized in that: include: Internal communication module, used for the information of internal equipment of direct solar storage power generation unit; Analog input module, used to directly sample the voltage and current on the low-voltage side of the step-up transformer, divided into two inputs: protection and measurement; The switch input module is used to access the protection action signal of the step-up transformer measurement and control device, and is used to instantly lock the output of the photovoltaic storage unit when the transformer protection is actuated; The switch output module is used to output multiple outputs, control the emergency power reduction of the equipment inside the photovoltaic power generation unit, and control the opening and closing of the circuit breaker on the low-voltage side of the step-up transformer and the circuit breaker of the energy storage equipment; An upward communication module is used to respectively access the monitoring system and the primary frequency modulation system; Human-machine interface module, including display screen interface, button interface, signal light interface and internal test communication interface; The control management module is used to collect and upload information about the internal equipment of the photovoltaic and energy storage power generation unit in real time, coordinate photovoltaic power generation and energy storage charging and discharging according to various remote control instructions received from the station control layer, and realize photovoltaic and energy storage combined power generation, peak regulation, and primary frequency regulation; it is used to control the energy storage charging and discharging according to the current and voltage on the low-voltage side of the step-up transformer collected in real time, and realize primary frequency and voltage regulation if the current frequency and voltage exceed the dead zone set value; it is used to automatically set the dynamic photovoltaic and energy storage power generation unit output control threshold on-site according to different weather conditions based on the photovoltaic output value collected in real time, and use this threshold as an instruction to realize photovoltaic and energy storage combined power generation.

2. The active control photovoltaic power generation unit coordination controller according to claim 1, characterized in that: The internal equipment of the light-storage power generation unit includes a photovoltaic inverter, a photovoltaic DC / DC, an energy storage converter, an energy storage DC / DC, a step-up transformer measurement and control device, an energy storage battery BMS, a meter, an energy storage environmental control and fire-fighting equipment.

3. The active control photovoltaic power generation unit coordination controller according to claim 1, characterized in that: The control strategies for photovoltaic and energy storage combined power generation when the station control layer issues control instructions include: The coordination controller receives the AGC power command of the station control layer, and adjusts the inverter and energy storage converter in real time according to the active power value Pagc issued by the AGC system, the maximum active power Pmax of the grid-connected point on the boost-to-low-voltage side, the real-time active power Ppcc of the grid-connected point on the boost-to-low-voltage side, the real-time active power Ppv of photovoltaic power, the active power Pcharge of energy storage, the active power Pdischarge of energy storage, and the energy storage SOC value: When Ppcc>Pagc, and the energy storage meets the charging conditions, that is, SOC<upper limit value, the energy storage is controlled to charge. When the battery is charged to the upper limit of SOC setting, the energy storage is on standby. If the Pagc value does not change, the inverter is controlled to limit power generation so that Ppv'=Ppcc'=Pagc, where Ppv' represents the real-time active power of the photovoltaic power after real-time adjustment, and Ppcc' represents the real-time active power of the grid-connected point on the low-voltage side of the boost converter after real-time adjustment; When Ppcc<Pagc, and the energy storage has the conditions for discharge, that is, SOC>lower limit value, the energy storage is controlled to discharge; when the battery is discharged to the lower limit of SOC setting, the energy storage is on standby, and if the Pagc value does not change, the inverter is controlled to generate electricity at the current maximum power Ppvmax=Ppccmax; When Pagc>Pmax, Pmax is used as the maximum power command limit to adjust the inverter and energy storage in real time.

4. The active control photovoltaic power generation unit coordination controller according to claim 1, characterized in that: The peak load control strategies when the station control layer issues control instructions include: The coordination controller receives the peak-shaving power instruction from the station control layer, and adjusts the inverter and energy storage in real time according to the active power value Ptf issued by the peak-shaving, the maximum active power Pmax of the grid-connected point on the boost-to-low-voltage side, the real-time active power Ppcc of the grid-connected point on the boost-to-low-voltage side, the real-time active power Ppv of the photovoltaic power generation, the active power Pcharge of the energy storage, the active power Pdischarge of the energy storage, and the energy storage SOC value: When Ppcc>Ptf, and the energy storage meets the charging conditions, that is, SOC<upper limit value, the energy storage is controlled to charge. When the battery is charged to the upper limit of SOC setting, the energy storage is on standby. If the Ptf value does not change, the inverter is controlled to limit power generation so that Ppv'=Ppcc'=Ptf, where Ppv' represents the real-time active power of the photovoltaic power after real-time adjustment, and Ppcc' represents the real-time active power of the grid-connected point on the low-voltage side of the boost converter after real-time adjustment; When Ppcc<Ptf, and the energy storage meets the discharge conditions, that is, SOC>lower limit value, the energy storage is controlled to discharge. When the battery is discharged to the lower limit of SOC setting, the energy storage is on standby. If the Ptf value does not change, the inverter is controlled to generate electricity at the current maximum power Ppvmax=Ppccmax; When Ptf>Pmax, Pmax is used as the maximum power command limit to adjust the inverter and energy storage in real time.

5. The active control photovoltaic power generation unit coordination controller according to claim 1, characterized in that: The voltage regulation control strategies when the station control layer issues control instructions include: The coordination controller receives the AVC power command from the station control layer, and adjusts the photovoltaic storage AC / DC, photovoltaic DC / DC and energy storage in real time according to the reactive power value Qavc, the maximum reactive power Qmax of the grid-connected point on the boost-to-low-voltage side, the real-time reactive power Qpcc of the grid-connected point on the boost-to-low-voltage side, the real-time reactive power Qpv of photovoltaic, the reactive power Qcharge of energy storage, the reactive power Qdischarge of energy storage, and the energy storage SOC value issued by the AVC system: When Qpcc>Qavc, and the energy storage meets the charging conditions, that is, SOC<upper limit value, the energy storage charging is controlled. When the battery is charged to the upper limit of SOC setting, the energy storage is on standby. If the Qagc value does not change, the solar storage AC / DC and photovoltaic DC / DC are controlled to limit generation, so that Qpv′=Qpcc′=Qavc, where Qpv′ represents the real-time photovoltaic reactive power after real-time adjustment, and Qpcc′ represents the real-time reactive power of the boost-to-low-voltage side grid-connected point after real-time adjustment; When Qpcc<Qagc, and the energy storage has the conditions for discharge, that is, SOC>lower limit value, the energy storage is controlled to discharge. When the battery is discharged to the lower limit of SOC setting, the energy storage is on standby. If the Qagc value does not change, the solar storage AC / DC and photovoltaic DC / DC are controlled to generate electricity at the current maximum power Qpvmax=Qpccmax; When Qagc>Qmax, Qmax is used as the maximum power command limit to adjust the inverter and energy storage in real time.

6. The active control photovoltaic power generation unit coordination controller according to claim 1, characterized in that: The primary frequency modulation control strategy when the station control layer issues control instructions includes: The coordination controller receives the power command of the primary frequency regulation control system at the station control layer, and adjusts the inverter and energy storage in real time according to the active power value Ptp issued by the primary frequency regulation, the maximum active power Pmax of the grid-connected point on the boost-to-low-voltage side, the real-time active power Ppcc of the grid-connected point on the boost-to-low-voltage side, the real-time active power Ppv of photovoltaic power, the active power Pcharge of energy storage, the active power Pdischarge of energy storage, and the energy storage SOC value: When Ppcc>Ptp, and the energy storage meets the charging conditions, that is, SOC<upper limit value, the energy storage charging is controlled. When the battery is charged to the upper limit of SOC setting, the energy storage is on standby. If the Ptf value does not change, the photovoltaic storage AC / DC and photovoltaic DC / DC are controlled to limit generation, so that Ppv′=Ppcc′=Ptf, where Ppv' represents the real-time active power of photovoltaic after real-time adjustment, and Ppcc' represents the real-time active power of the boost-to-low-voltage side grid-connected point after real-time adjustment; When Ppcc<Ptp, and the energy storage meets the discharge conditions, that is, SOC>lower limit value, the energy storage is controlled to discharge. When the battery is discharged to the lower limit of SOC setting, the energy storage is on standby. If the Ptf value does not change, the solar storage AC / DC and photovoltaic DC / DC are controlled to generate electricity at the current maximum power Ppvmax=Ppccmax; When Ptp>Pmax, Pmax is used as the maximum power command limit to adjust the solar storage AC / DC, photovoltaic DC / DC and energy storage in real time.

7. The active control photovoltaic power generation unit coordination controller according to claim 1, characterized in that: The control strategies for photovoltaic and energy storage combined power generation when control instructions are issued locally include: The coordination controller automatically and dynamically sets the power control threshold of the photovoltaic power generation unit grid connection point according to the collected photovoltaic output in three preset time periods every day; The coordination controller dynamically sets the maximum output control threshold value Pdtagc of the photovoltaic power generation unit in each period of the day according to the maximum active power Pmax of the grid-connected point on the boost-to-low-voltage side, the real-time active power Ppcc of the grid-connected point on the boost-to-low-voltage side, the real-time active power Ppv of the photovoltaic power generation unit, the active power Pcharge of the energy storage unit, the active power Pdischarge of the energy storage unit, and the energy storage SOC value, and adjusts the inverter and energy storage unit in real time: The first period: in the morning period, determine whether the photovoltaic power Ppv is greater than the preset percentage of Pmax. If so, use the preset percentage of Pmax as the output threshold Pdtagc for this period. Otherwise, use the preset percentage of Ppv for this period as the threshold Pdtagc for this period: When Ppcc>Pdtagc, and the energy storage meets the charging conditions, that is, SOC<upper limit value, the energy storage is controlled to charge. When the battery is charged to the upper limit of SOC setting, the energy storage is on standby. If the Pdtagc value does not change, the inverter is controlled to limit power generation so that Ppv'=Ppcc′=Pdtagc, where Ppv' represents the real-time active power of the photovoltaic power after real-time adjustment, and Ppcc' represents the real-time active power of the grid-connected point on the low-voltage side of the boost converter after real-time adjustment; When Ppcc<Pdtagc, and the energy storage has the conditions for discharge, that is, SOC>lower limit value, the energy storage is controlled to discharge; when the battery is discharged to the lower limit of SOC setting, the energy storage is on standby. If the Pdtagc value does not change, the inverter is controlled to generate electricity at the current maximum power Ppvmax=Ppccmax; Second period: During the noon period, determine whether the photovoltaic power Ppv is greater than the preset percentage of Pmax. If so, use the preset percentage of Pma as the threshold value Pdtggc for this period. Otherwise, use the preset percentage of Ppv at that moment as the threshold value Pdtagc for this period. The control strategy is the same as in the first period; The third period: in the afternoon, determine whether the photovoltaic power Ppv is greater than the preset percentage of Pmax. If so, use the preset percentage of Pmax as the threshold value Pdtggc of this period. Otherwise, use the preset percentage of Ppv at this moment as the threshold value Pdtagc of this period. The control strategy is the same as in the first period.

8. The active control photovoltaic power generation unit coordination controller according to claim 1, characterized in that: The primary frequency regulation control strategy when the control command is issued locally includes: The coordination controller calculates the grid connection point frequency by collecting the current and voltage on the boost-to-low voltage side, and calculates the active power deviation command Ptp according to the current frequency exceeding the set reference frequency dead zone range. At the same time, according to the maximum active power Pmax of the boost-to-low voltage side grid connection point, the real-time active power Ppcc of the boost-to-low voltage side grid connection point, the real-time active power Ppv of the photovoltaic power generation, the active power Pcharge of the energy storage that can be charged, the active power Pdischarge of the energy storage that can be discharged, and the energy storage SOC value, the inverter and energy storage are adjusted in real time: When the frequency of the grid connection point is lower than the reference frequency and the frequency deviation exceeds the dead zone, the local frequency regulation command is to increase; If Pdischarge>Ptp, the energy storage is controlled to discharge at the difference between the two values, so that Pdischarge'=Ptp, where Pdischarge' represents the active power that can be discharged by the energy storage after adjustment; If Pdischarge<Ptp, control the inverter and energy storage to discharge at the current maximum power Pdischargemax+Ppvmax=Ppccmax; When the grid connection point frequency is higher than the reference frequency and the frequency deviation exceeds the dead zone, the local frequency regulation command is to adjust downward: If Pcharge>Ptp, the energy storage is controlled to be charged with the difference between the two, so that Pcharge'=Ptp, where Pcharge' represents the adjusted active power of the energy storage; If Pcharge<Ptp, the energy storage is controlled to charge at the current maximum power Pchargemax, and the inverter is controlled to limit power generation so that Pchargemax+Ppv'=Ptp.

9. The active control photovoltaic power generation unit coordination controller according to claim 1, characterized in that: The voltage regulation control strategies when the control instructions are issued locally include: The coordinated controller collects the voltage on the boost-to-low voltage side, calculates the reactive power deviation command Qty according to the current voltage exceeding the set reference voltage dead zone range, and adjusts the inverter and energy storage in real time according to the maximum reactive power Qmax of the boost-to-low voltage side grid-connected point, the real-time reactive power Qpcc of the boost-to-low voltage side grid-connected point, the real-time reactive power Qpv of the photovoltaic power generation, the reactive power Qcharge of the energy storage that can be charged, the reactive power Qdischarge of the energy storage that can be discharged, and the energy storage SOC value: When the grid-connected point voltage is lower than the reference voltage and the voltage deviation exceeds the dead zone, the local voltage regulation command is to increase: If Qdischarge>Qty, control the energy storage to discharge at the difference between the two, so that Qdischarge′=Qty; if Qdischarge<Qty, control the inverter and energy storage to discharge at the current maximum power Qdischargemax+Qpvmax=Qpccmax; When the grid-connected point voltage is higher than the reference voltage and the voltage deviation exceeds the dead zone, the local voltage regulation command is to adjust downward: If Qcharge>Qty, the energy storage is controlled to be charged with the difference between the two, so that Qcharge′=Qty, where Qcharge′ represents the adjusted chargeable reactive power of the energy storage; if Qcharge<Qty, the energy storage is controlled to be charged with the current maximum power Qchargemax, and the inverter is controlled to limit power generation, so that Qchargemax+Qpv′=Qty, where Qpv′ represents the adjusted real-time reactive power of the photovoltaic power plant.

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